//! Certificate creation wizard and renewal form.
use serde_json::{json, Value};
use sycamore::prelude::*;
use wasm_bindgen_futures::spawn_local;

use crate::api;
use crate::components::extension_form::{
    build_extra_extensions, extension_fields, load_extra_extensions, ExtensionSignals,
};
use crate::components::nav::{app_nav, whoami};
use crate::components::ui::{page_header, toast_error};
use crate::model::{CertificateDetail, CertificateSummary, KeySummary, Me, TemplateSummary};

const DEFAULT_EXPLICIT_DN: [&str; 7] = ["C", "ST", "L", "O", "OU", "CN", "emailAddress"];

#[derive(Clone, Copy)]
struct CertFormSignals {
    explicit_dn: Signal<Vec<String>>,
    subject_extra: Signal<String>,
    cn: Signal<String>,
    country: Signal<String>,
    state: Signal<String>,
    locality: Signal<String>,
    organization: Signal<String>,
    org_unit: Signal<String>,
    email: Signal<String>,
    ca_mode: Signal<String>,
    path_length: Signal<String>,
    bc_critical: Signal<bool>,
    ku_digital: Signal<bool>,
    ku_encipher: Signal<bool>,
    ku_key_agreement: Signal<bool>,
    ku_cert_sign: Signal<bool>,
    ku_crl_sign: Signal<bool>,
    ku_critical: Signal<bool>,
    eku_server: Signal<bool>,
    eku_client: Signal<bool>,
    eku_code: Signal<bool>,
    eku_email: Signal<bool>,
    eku_time: Signal<bool>,
    eku_ocsp: Signal<bool>,
    eku_critical: Signal<bool>,
    san_text: Signal<String>,
    ski: Signal<bool>,
    aki: Signal<bool>,
    ocsp_staple: Signal<bool>,
    ext: ExtensionSignals,
    validity_mode: Signal<String>,
    validity_amount: Signal<String>,
    validity_unit: Signal<String>,
    midnight: Signal<bool>,
    not_before_text: Signal<String>,
    not_after_text: Signal<String>,
    no_expiration: Signal<bool>,
}

pub fn CertificateNewPage(vault_id: String, from_cert: Option<String>) -> View {
    let id: &'static str = Box::leak(vault_id.clone().into_boxed_str());
    let me = create_signal(None::<Me>);
    let keys = create_signal(Vec::<KeySummary>::new());
    let signers = create_signal(Vec::<CertificateSummary>::new());
    let templates = create_signal(Vec::<TemplateSummary>::new());
    let error = create_signal(None::<String>);
    let saving = create_signal(false);

    let request_id = query_param("request").unwrap_or_default();
    let request_mode = !request_id.is_empty();
    let request_id_for_load = request_id.clone();

    let name = create_signal(String::new());
    let comment = create_signal(String::new());
    let signer_id = create_signal("self".to_string());
    let key_id = create_signal(String::new());
    let new_key = create_signal(false);
    let key_type = create_signal("rsa".to_string());
    let key_size = create_signal("2048".to_string());
    let template_id = create_signal(String::new());
    let template_apply_mode = create_signal("all".to_string());
    let ca_default_template = create_signal(None::<String>);
    let ca_default_name = create_signal(String::new());
    let signature_hash = create_signal("sha256".to_string());

    let cn = create_signal(String::new());
    let country = create_signal(String::new());
    let state = create_signal(String::new());
    let locality = create_signal(String::new());
    let organization = create_signal(String::new());
    let org_unit = create_signal(String::new());
    let email = create_signal(String::new());

    let ca_mode = create_signal("end".to_string());
    let path_length = create_signal(String::new());
    let bc_critical = create_signal(true);
    let ku_digital = create_signal(true);
    let ku_encipher = create_signal(false);
    let ku_key_agreement = create_signal(false);
    let ku_cert_sign = create_signal(false);
    let ku_crl_sign = create_signal(false);
    let ku_critical = create_signal(true);
    let eku_server = create_signal(false);
    let eku_client = create_signal(false);
    let eku_code = create_signal(false);
    let eku_email = create_signal(false);
    let eku_time = create_signal(false);
    let eku_ocsp = create_signal(false);
    let eku_critical = create_signal(false);
    let san_text = create_signal(String::new());
    let ski = create_signal(true);
    let aki = create_signal(true);
    let ocsp_staple = create_signal(false);
    let crl_urls = create_signal(String::new());
    let aia_ocsp = create_signal(String::new());
    let aia_ca_issuers = create_signal(String::new());
    let nc_permitted = create_signal(String::new());
    let nc_excluded = create_signal(String::new());
    let policy_oids = create_signal(String::new());
    let policy_cps = create_signal(String::new());
    let policy_require = create_signal(String::new());
    let policy_inhibit = create_signal(String::new());
    let inhibit_any = create_signal(String::new());
    let advanced_json = create_signal(String::new());
    let ext = ExtensionSignals {
        crl_urls,
        aia_ocsp,
        aia_ca_issuers,
        nc_permitted,
        nc_excluded,
        policy_oids,
        policy_cps,
        policy_require,
        policy_inhibit,
        inhibit_any,
        advanced_json,
    };

    let preview_text = create_signal(String::new());
    let validity_mode = create_signal("duration".to_string());
    let validity_amount = create_signal("365".to_string());
    let validity_unit = create_signal("days".to_string());
    let midnight = create_signal(false);
    let not_before_text = create_signal(String::new());
    let not_after_text = create_signal(String::new());
    let no_expiration = create_signal(false);
    let explicit_dn = create_signal(
        DEFAULT_EXPLICIT_DN
            .iter()
            .map(|v| v.to_string())
            .collect::<Vec<_>>(),
    );
    let subject_extra = create_signal(String::new());
    let form = CertFormSignals {
        explicit_dn,
        subject_extra,
        cn,
        country,
        state,
        locality,
        organization,
        org_unit,
        email,
        ca_mode,
        path_length,
        bc_critical,
        ku_digital,
        ku_encipher,
        ku_key_agreement,
        ku_cert_sign,
        ku_crl_sign,
        ku_critical,
        eku_server,
        eku_client,
        eku_code,
        eku_email,
        eku_time,
        eku_ocsp,
        eku_critical,
        san_text,
        ski,
        aki,
        ocsp_staple,
        ext,
        validity_mode,
        validity_amount,
        validity_unit,
        midnight,
        not_before_text,
        not_after_text,
        no_expiration,
    };

    spawn_local(async move {
        if let Ok(user) = api::me().await {
            if me.is_alive() {
                me.set(Some(user));
            }
        }
        if let Ok(page) = api::keys(&id).await {
            keys.set(page.results);
        }
        if let Ok(page) = api::certificates(&id).await {
            signers.set(
                page.results
                    .into_iter()
                    .filter(|cert| cert.is_ca && cert.has_private_key)
                    .collect(),
            );
        }
        if let Ok(page) = api::templates(&id).await {
            templates.set(page.results);
        }
        if let Ok(value) = api::vault_settings(&id).await {
            if let Some(settings) = value.get("settings") {
                if let Some(hash) = settings.get("default_hash").and_then(|v| v.as_str()) {
                    signature_hash.set(hash.to_string());
                }
                if let Some(key) = settings.get("default_key") {
                    if let Some(kind) = key.get("type").and_then(|v| v.as_str()) {
                        key_type.set(kind.to_string());
                    }
                    if let Some(size) = key.get("size").and_then(|v| v.as_i64()) {
                        key_size.set(size.to_string());
                    }
                }
                if let Some(items) = settings.get("explicit_dn").and_then(|v| v.as_array()) {
                    let names = items
                        .iter()
                        .filter_map(|v| v.as_str())
                        .map(|v| v.to_string())
                        .collect::<Vec<_>>();
                    if !names.is_empty() {
                        explicit_dn.set(names);
                    }
                }
                if let Some(validity) = settings.get("default_validity") {
                    if let Some(amount) = validity.get("amount").and_then(|v| v.as_i64()) {
                        validity_amount.set(amount.to_string());
                    }
                    if let Some(unit) = validity.get("unit").and_then(|v| v.as_str()) {
                        validity_unit.set(unit.to_string());
                    }
                }
            }
        }
        if !request_mode {
            if let Some(cert_id) = from_cert.clone() {
                if let Ok(value) = api::certificate(&id, &cert_id).await {
                    name.set(format!("{} copy", value.summary.name));
                    comment.set(value.summary.comment.clone());
                    if let Some(key) = value.summary.key_id.clone() {
                        key_id.set(key);
                    }
                    if let Some(issuer) = value.summary.issuer_id.clone() {
                        if issuer != value.summary.id {
                            signer_id.set(issuer);
                        }
                    }
                    if let Some(spec) = value
                        .cert_spec
                        .get("signature_hash")
                        .and_then(|v| v.as_str())
                    {
                        signature_hash.set(spec.to_string());
                    }
                    let subject_json =
                        serde_json::to_value(&value.subject_entries).unwrap_or(json!([]));
                    apply_subject_json(&form, &subject_json);
                    apply_extension_spec(&form, &value.extension_spec);
                    no_expiration.set(value.summary.no_expiration);
                }
            }
        }
        if request_mode {
            if let Ok(value) = api::request(&id, &request_id_for_load).await {
                name.set(format!("{} certificate", value.summary.name));
                let subject_json =
                    serde_json::to_value(&value.subject_entries).unwrap_or(json!([]));
                apply_subject_json(&form, &subject_json);
            }
        }
    });

    let apply_template_id = move |template: String, mode: String| {
        if template.is_empty() {
            return;
        }
        let target = match build_target(&form) {
            Ok(target) => target,
            Err(message) => {
                error.set(Some(message));
                return;
            }
        };
        let payload = json!({
            "target": target,
            "apply_subject": mode == "all" || mode == "subject",
            "apply_extensions": mode == "all" || mode == "extensions",
        });
        spawn_local(async move {
            match api::apply_template(&id, &template, &payload).await {
                Ok(merged) => {
                    if mode == "all" || mode == "subject" {
                        let subject = merged.get("subject").cloned().unwrap_or_else(|| json!([]));
                        apply_subject_json(&form, &subject);
                    }
                    if mode == "all" || mode == "extensions" {
                        let extensions = merged
                            .get("extensions")
                            .cloned()
                            .unwrap_or_else(|| json!({}));
                        apply_extension_spec(&form, &extensions);
                        if let Some(validity) = merged.get("validity") {
                            apply_validity_json(&form, validity);
                        }
                    }
                }
                Err(message) if message == api::LOGIN_REQUIRED => {}
                Err(message) => error.set(Some(message)),
            }
        });
    };
    let apply_template = move |_| {
        apply_template_id(template_id.get_clone(), template_apply_mode.get_clone());
    };
    let apply_ca_default = move |_: web_sys::MouseEvent| {
        if let Some(template) = ca_default_template.get_clone() {
            template_id.set(template.clone());
            template_apply_mode.set("all".to_string());
            apply_template_id(template, "all".to_string());
        }
    };

    create_effect(move || {
        let signer = signer_id.get_clone();
        if signer == "self" {
            ca_default_template.set(None);
            ca_default_name.set(String::new());
            return;
        }
        spawn_local(async move {
            if let Ok(value) = api::ca_info(&id, &signer).await {
                let template = value
                    .get("default_template")
                    .and_then(|v| v.as_str())
                    .map(|v| v.to_string());
                let label = match template.as_deref() {
                    Some("builtin:ca") => "CA".to_string(),
                    Some("builtin:tls-server") => "TLS server".to_string(),
                    Some("builtin:tls-client") => "TLS client".to_string(),
                    Some(other) => match api::template(&id, other).await {
                        Ok(template) => template.name,
                        Err(_) => other.to_string(),
                    },
                    None => String::new(),
                };
                ca_default_template.set(template);
                ca_default_name.set(label);
            }
        });
    });

    let submit = {
        let id = id.clone();
        let request_id = request_id.clone();
        move |_| {
            let cert_name = name.get_clone();
            if cert_name.trim().is_empty() {
                error.set(Some("certificate name is required".to_string()));
                return;
            }
            let subject = match build_subject(&form) {
                Ok(subject) => subject,
                Err(message) => {
                    error.set(Some(message));
                    return;
                }
            };
            if subject.is_empty() {
                error.set(Some("the subject must not be empty".to_string()));
                return;
            }
            let extensions = match build_extensions(&form) {
                Ok(extensions) => extensions,
                Err(message) => {
                    error.set(Some(message));
                    return;
                }
            };
            let signer = signer_id.get_clone();
            let mut payload = json!({
                "name": cert_name,
                "comment": comment.get_clone(),
                "subject": subject,
                "extensions": extensions,
                "signature_hash": signature_hash.get_clone(),
                "signer_id": if signer == "self" { serde_json::Value::Null } else { json!(signer) },
                "validity": validity_value(&form),
            });
            if validity_mode.get_clone() == "absolute" && !no_expiration.get() {
                payload["not_before"] = json!(not_before_text.get_clone());
                payload["not_after"] = json!(not_after_text.get_clone());
            }
            if !request_id.is_empty() {
                payload["request_id"] = json!(request_id);
                payload["modify_subject"] = json!(true);
                payload["copy_request_extensions"] = json!(false);
            } else if new_key.get() {
                payload["new_key"] = json!({
                    "key_type": key_type.get_clone(),
                    "size": key_size.get_clone().parse::<i64>().unwrap_or(2048),
                    "name": format!("{} key", name.get_clone()),
                });
            } else if !key_id.get_clone().is_empty() {
                payload["key_id"] = json!(key_id.get_clone());
            } else {
                error.set(Some("select a key or generate a new one".to_string()));
                return;
            }
            saving.set(true);
            let id = id.clone();
            spawn_local(async move {
                match api::create_certificate(&id, &payload).await {
                    Ok(cert) => {
                        saving.set(false);
                        sycamore_router::navigate(&format!(
                            "/vaults/{}/certificates/{}",
                            id, cert.summary.id
                        ));
                        return;
                    }
                    Err(message) if message == api::LOGIN_REQUIRED => {}
                    Err(message) => error.set(Some(message)),
                }
                if saving.is_alive() {
                    saving.set(false);
                }
            });
        }
    };

    let validate = {
        let id = id.clone();
        move |_| {
            let subject = match build_subject(&form) {
                Ok(subject) => subject,
                Err(message) => {
                    error.set(Some(message));
                    return;
                }
            };
            let extensions = match build_extensions(&form) {
                Ok(extensions) => extensions,
                Err(message) => {
                    error.set(Some(message));
                    return;
                }
            };
            let signer = signer_id.get_clone();
            let payload = json!({
                "name": if name.get_clone().is_empty() { "preview".to_string() } else { name.get_clone() },
                "subject": subject,
                "extensions": extensions,
                "signature_hash": signature_hash.get_clone(),
                "signer_id": if signer == "self" { serde_json::Value::Null } else { json!(signer) },
                "validity": validity_value(&form),
            });
            let mut payload = payload;
            if validity_mode.get_clone() == "absolute" && !no_expiration.get() {
                payload["not_before"] = json!(not_before_text.get_clone());
                payload["not_after"] = json!(not_after_text.get_clone());
            }
            let id = id.clone();
            spawn_local(async move {
                match api::preview_certificate(&id, &payload).await {
                    Ok(value) => {
                        let mut text = String::new();
                        if let Some(rows) = value.get("extensions").and_then(|v| v.as_array()) {
                            for row in rows {
                                let name = row.get("name").and_then(|v| v.as_str()).unwrap_or("");
                                let value = row.get("value").and_then(|v| v.as_str()).unwrap_or("");
                                text.push_str(&format!("{name}: {value}\n"));
                            }
                        }
                        preview_text.set(text);
                    }
                    Err(message) if message == api::LOGIN_REQUIRED => {}
                    Err(message) => error.set(Some(message)),
                }
            });
        }
    };

    let signer_options = move || {
        signers
            .get_clone()
            .into_iter()
            .map(|cert| {
                view! {
                    option(value=cert.id.clone()) { (cert.name.clone()) }
                }
            })
            .collect::<Vec<View>>()
    };
    let key_options = move || {
        keys.get_clone()
            .into_iter()
            .filter(|key| key.has_private)
            .map(|key| {
                view! {
                    option(value=key.id.clone()) { (key.name.clone()) }
                }
            })
            .collect::<Vec<View>>()
    };
    let template_options = move || {
        templates.get_clone().into_iter().map(|template| view! {
            option(value=template.id.clone()) { (if template.builtin { format!("[built-in] {}", template.name) } else { template.name.clone() }) }
        }).collect::<Vec<View>>()
    };

    let nav = move || match me.get_clone() {
        Some(user) => whoami(&user),
        None => view! {},
    };

    view! {
        (app_nav("/", Some(id), nav))
        main(class="container page-shell py-4") {
            (toast_error(error))
            (page_header(
                if request_mode { "Sign certificate request" } else { "New certificate" },
                "Certificates can be self-signed or issued by a CA with a private key in this vault.",
                view! { a(class="btn btn-outline-light", href=format!("/vaults/{id}/certificates")) { "Cancel" } },
            ))
            (if request_mode {
                view! { div(class="alert alert-info") { "The subject and public key come from the selected request; the fields below override the subject." } }
            } else {
                view! {}
            })
            (if let Some(default) = ca_default_template.get_clone() {
                if default != template_id.get_clone() {
                    view! {
                        div(class="alert alert-info d-flex align-items-center justify-content-between") {
                            span() { (format!("CA default template: {}", ca_default_name.get_clone())) }
                            button(class="btn btn-sm btn-outline-light", on:click=apply_ca_default) { "Apply CA default" }
                        }
                    }
                } else {
                    view! {}
                }
            } else {
                view! {}
            })
            div(class="card") {
                div(class="card-body") {
                    div(class="form-section") {
                        div(class="form-section-title") { "Source" }
                        div(class="row g-3") {
                            div(class="col-md-6") {
                                label(class="form-label") { "Issuer" }
                                select(class="form-select", bind:value=signer_id) {
                                    option(value="self") { "Self-signed" }
                                    (signer_options())
                                }
                            }
                            div(class="col-md-6") {
                                label(class="form-label") { "Signature hash" }
                                select(class="form-select", bind:value=signature_hash) {
                                    option(value="sha256") { "SHA-256" }
                                    option(value="sha384") { "SHA-384" }
                                    option(value="sha512") { "SHA-512" }
                                    option(value="sha1") { "SHA-1" }
                                }
                            }
                            div(class="col-md-6") {
                                label(class="form-label") { "Template" }
                                div(class="input-group") {
                                    select(class="form-select", bind:value=template_id) {
                                        option(value="") { "— no template —" }
                                        (template_options())
                                    }
                                    select(class="form-select", style="max-width: 11rem", bind:value=template_apply_mode) {
                                        option(value="all") { "Apply all" }
                                        option(value="subject") { "Subject only" }
                                        option(value="extensions") { "Extensions + validity" }
                                    }
                                    button(class="btn btn-outline-light", on:click=apply_template) { "Apply" }
                                }
                            }
                            div(class="col-md-6") {
                                label(class="form-label") { "Internal name" }
                                input(class="form-control", bind:value=name)
                            }
                            div(class="col-12") {
                                label(class="form-label") { "Comment" }
                                textarea(class="form-control", rows="2", bind:value=comment) {}
                            }
                        }
                    }
                    div(class="form-section") {
                        div(class="form-section-title") { "Subject" }
                        div(class="row g-3") {
                            (subject_fields(&form))
                            div(class="col-12") {
                                label(class="form-label") { "Additional subject attributes (JSON)" }
                                textarea(class="form-control mono", rows="2",
                                         placeholder=r#"[{"name":"serialNumber","value":"1234"}]"#,
                                         bind:value=subject_extra) {}
                                div(class="form-text") {
                                    "Used for attributes not shown above; the order above follows the vault's explicit DN setting."
                                }
                            }
                        }
                    }
                    (if request_mode {
                        view! {}
                    } else {
                        view! {
                            div(class="form-section") {
                                div(class="form-section-title") { "Private key" }
                                div(class="form-check mb-2") {
                                    input(class="form-check-input", r#type="checkbox", id="new-key", bind:checked=new_key)
                                    label(class="form-check-label", r#for="new-key") { "Generate a new key" }
                                }
                                (if new_key.get() {
                                    view! {
                                        div(class="row g-3") {
                                            div(class="col-md-4") {
                                                label(class="form-label") { "Key type" }
                                                select(class="form-select", bind:value=key_type) {
                                                    option(value="rsa") { "RSA" }
                                                    option(value="ec") { "EC" }
                                                    option(value="ed25519") { "ED25519" }
                                                }
                                            }
                                            div(class="col-md-4") {
                                                label(class="form-label") { "Key size" }
                                                input(class="form-control", bind:value=key_size)
                                            }
                                        }
                                    }
                                } else {
                                    view! {
                                        label(class="form-label") { "Existing key" }
                                        select(class="form-select", bind:value=key_id) {
                                            option(value="") { "— select a key —" }
                                            (key_options())
                                        }
                                    }
                                })
                            }
                        }
                    })
                    div(class="form-section") {
                        div(class="form-section-title") { "Extensions" }
                        div(class="row g-3" ) {
                            div(class="col-md-4") {
                                label(class="form-label") { "Basic constraints" }
                                select(class="form-select", bind:value=ca_mode) {
                                    option(value="end") { "End entity (CA:FALSE)" }
                                    option(value="ca") { "Certification authority (CA:TRUE)" }
                                    option(value="none") { "Not defined" }
                                }
                            }
                            div(class="col-md-3") {
                                label(class="form-label") { "Path length" }
                                input(class="form-control", placeholder="unlimited", bind:value=path_length)
                            }
                            div(class="col-md-3 d-flex align-items-end") {
                                div(class="form-check") {
                                    input(class="form-check-input", r#type="checkbox", bind:checked=bc_critical)
                                    label(class="form-check-label") { "Critical" }
                                }
                            }
                            div(class="col-md-2 d-flex align-items-end") {
                                div(class="form-check") {
                                    input(class="form-check-input", r#type="checkbox", bind:checked=ski)
                                    label(class="form-check-label") { "SKI" }
                                }
                            }
                        }
                        div(class="row g-3 mt-1") {
                            div(class="col-md-6") {
                                div(class="form-section-title") { "Key usage" }
                                (check("Digital signature", ku_digital))
                                (check("Key encipherment", ku_encipher))
                                (check("Key agreement", ku_key_agreement))
                                (check("Certificate sign", ku_cert_sign))
                                (check("CRL sign", ku_crl_sign))
                                (check("Critical", ku_critical))
                            }
                            div(class="col-md-6") {
                                div(class="form-section-title") { "Extended key usage" }
                                (check("TLS server", eku_server))
                                (check("TLS client", eku_client))
                                (check("Code signing", eku_code))
                                (check("E-mail protection", eku_email))
                                (check("Time stamping", eku_time))
                                (check("OCSP signing", eku_ocsp))
                                (check("Critical", eku_critical))
                            }
                            div(class="col-md-6") {
                                div(class="form-section-title") { "Subject alternative names" }
                                input(class="form-control", placeholder="DNS:example.com, IP:192.0.2.1", bind:value=san_text)
                            }
                            div(class="col-md-6") {
                                div(class="form-section-title") { "Key identifier / OCSP" }
                                (check("Authority key identifier", aki))
                                (check("OCSP stapling", ocsp_staple))
                            }
                        }
                    }
                    (extension_fields(&ext))
                    div(class="form-section") {
                        div(class="form-section-title") { "Validity" }
                        div(class="row g-3") {
                            div(class="col-md-3") {
                                label(class="form-label") { "Mode" }
                                select(class="form-select", bind:value=validity_mode) {
                                    option(value="duration") { "Duration" }
                                    option(value="absolute") { "Absolute dates" }
                                }
                            }
                            (if validity_mode.get_clone() == "duration" {
                                view! {
                                    div(class="col-md-3") {
                                        label(class="form-label") { "Duration" }
                                        input(class="form-control", disabled=no_expiration.get(), bind:value=validity_amount)
                                    }
                                    div(class="col-md-3") {
                                        label(class="form-label") { "Unit" }
                                        select(class="form-select", disabled=no_expiration.get(), bind:value=validity_unit) {
                                            option(value="days") { "Days" }
                                            option(value="months") { "Months" }
                                            option(value="years") { "Years" }
                                        }
                                    }
                                    div(class="col-md-3 d-flex align-items-end") {
                                        div(class="form-check") {
                                            input(class="form-check-input", r#type="checkbox", disabled=no_expiration.get(), bind:checked=midnight)
                                            label(class="form-check-label") { "Round to midnight" }
                                        }
                                    }
                                }
                            } else {
                                view! {
                                    div(class="col-md-4") {
                                        label(class="form-label") { "Not before" }
                                        input(class="form-control", r#type="datetime-local", disabled=no_expiration.get(), bind:value=not_before_text)
                                    }
                                    div(class="col-md-4") {
                                        label(class="form-label") { "Not after" }
                                        input(class="form-control", r#type="datetime-local", disabled=no_expiration.get(), bind:value=not_after_text)
                                    }
                                }
                            })
                            div(class="col-md-3 d-flex align-items-end") {
                                div(class="form-check") {
                                    input(class="form-check-input", r#type="checkbox", bind:checked=no_expiration)
                                    label(class="form-check-label") { "No well-defined expiration" }
                                }
                            }
                        }
                    }
                    (if preview_text.get_clone().is_empty() {
                        view! {}
                    } else {
                        view! {
                            div(class="card mb-3") {
                                div(class="card-header") { "Extension preview" }
                                div(class="card-body") { pre(class="pem mb-0") { (preview_text.get_clone()) } }
                            }
                        }
                    })
                    button(class="btn btn-outline-light btn-lg me-2", on:click=validate) { "Validate extensions" }
                    button(class="btn btn-primary btn-lg", disabled=saving.get(), on:click=submit) {
                        (if saving.get() { "Issuing…" } else if request_mode { "Issue certificate" } else { "Create certificate" })
                    }
                }
            }
        }
    }
}

pub fn CertificateRenewPage(vault_id: String, cert_id: String) -> View {
    let id: &'static str = Box::leak(vault_id.clone().into_boxed_str());
    let cert_id_value: &'static str = Box::leak(cert_id.clone().into_boxed_str());
    let me = create_signal(None::<Me>);
    let cert = create_signal(None::<CertificateDetail>);
    let error = create_signal(None::<String>);
    let loading = create_signal(true);
    let saving = create_signal(false);
    let name = create_signal(String::new());
    let amount = create_signal("365".to_string());
    let unit = create_signal("days".to_string());
    let keep_serial = create_signal(false);
    let revoke_old = create_signal(false);
    let replace_old = create_signal(false);

    spawn_local(async move {
        match api::me().await {
            Ok(user) => {
                me.set(Some(user));
                match api::certificate(&id, &cert_id_value).await {
                    Ok(value) => {
                        name.set(value.summary.name.clone());
                        cert.set(Some(value));
                    }
                    Err(message) => error.set(Some(message)),
                }
            }
            Err(message) if message == api::LOGIN_REQUIRED => {}
            Err(message) => error.set(Some(message)),
        }
        loading.set(false);
    });

    let submit = {
        let id = id.clone();
        let cert_id_value = cert_id_value.clone();
        move |_| {
            let id = id.clone();
            let cert_id_value = cert_id_value.clone();
            let payload = json!({
                "name": name.get_clone(),
                "validity": {"amount": amount.get_clone().parse::<i64>().unwrap_or(365), "unit": unit.get_clone()},
                "keep_serial": keep_serial.get(),
                "revoke_old": revoke_old.get(),
                "replace_old": replace_old.get(),
            });
            saving.set(true);
            spawn_local(async move {
                match api::renew_certificate(&id, &cert_id_value, &payload).await {
                    Ok(value) => {
                        saving.set(false);
                        sycamore_router::navigate(&format!(
                            "/vaults/{}/certificates/{}",
                            id, value.summary.id
                        ));
                        return;
                    }
                    Err(message) if message == api::LOGIN_REQUIRED => {}
                    Err(message) => error.set(Some(message)),
                }
                if saving.is_alive() {
                    saving.set(false);
                }
            });
        }
    };

    let content = move || {
        if loading.get() {
            return crate::components::ui::spinner();
        }
        let Some(value) = cert.get_clone() else {
            return crate::components::ui::empty_state("Certificate not found.");
        };
        view! {
            (page_header("Renew certificate", &format!("Issued by {}", value.issuer_name), view! {
                a(class="btn btn-outline-light", href=format!("/vaults/{id}/certificates/{cert_id_value}")) { "Cancel" }
            }))
            div(class="card") {
                div(class="card-body") {
                    div(class="row g-3") {
                        div(class="col-md-8") {
                            label(class="form-label") { "New internal name" }
                            input(class="form-control", bind:value=name)
                        }
                        div(class="col-md-2") {
                            label(class="form-label") { "Duration" }
                            input(class="form-control", bind:value=amount)
                        }
                        div(class="col-md-2") {
                            label(class="form-label") { "Unit" }
                            select(class="form-select", bind:value=unit) {
                                option(value="days") { "Days" }
                                option(value="months") { "Months" }
                                option(value="years") { "Years" }
                            }
                        }
                    }
                    div(class="form-check mt-3") {
                        input(class="form-check-input", r#type="checkbox", id="keep-serial", bind:checked=keep_serial)
                        label(class="form-check-label", r#for="keep-serial") { "Keep serial number" }
                    }
                    div(class="form-check") {
                        input(class="form-check-input", r#type="checkbox", id="revoke-old", bind:checked=revoke_old)
                        label(class="form-check-label", r#for="revoke-old") { "Revoke old certificate" }
                    }
                    div(class="form-check mb-3") {
                        input(class="form-check-input", r#type="checkbox", id="replace-old", bind:checked=replace_old)
                        label(class="form-check-label", r#for="replace-old") { "Replace old certificate" }
                    }
                    button(class="btn btn-primary", disabled=saving.get(), on:click=submit) {
                        (if saving.get() { "Renewing…" } else { "Renew certificate" })
                    }
                }
            }
        }
    };

    let nav = move || match me.get_clone() {
        Some(user) => whoami(&user),
        None => view! {},
    };

    view! {
        (app_nav("/", Some(id), nav))
        main(class="container page-shell py-4") {
            (toast_error(error))
            (content)
        }
    }
}

fn subject_label(name: &str) -> Option<&'static str> {
    match name {
        "CN" => Some("Common name (CN)"),
        "O" => Some("Organization (O)"),
        "OU" => Some("Organizational unit (OU)"),
        "C" => Some("Country (C)"),
        "ST" => Some("State / province (ST)"),
        "L" => Some("Locality (L)"),
        "emailAddress" => Some("E-mail address"),
        _ => None,
    }
}

fn subject_signal(name: &str, form: &CertFormSignals) -> Option<Signal<String>> {
    match name {
        "CN" => Some(form.cn),
        "O" => Some(form.organization),
        "OU" => Some(form.org_unit),
        "C" => Some(form.country),
        "ST" => Some(form.state),
        "L" => Some(form.locality),
        "emailAddress" => Some(form.email),
        _ => None,
    }
}

fn subject_field(name: &str, form: &CertFormSignals) -> Option<View> {
    let label = subject_label(name)?;
    let value = subject_signal(name, form)?;
    Some(view! {
        div(class="col-md-6") {
            label(class="form-label") { (label) }
            input(class="form-control", bind:value=value)
        }
    })
}

fn subject_fields(form: &CertFormSignals) -> Vec<View> {
    let mut names = form.explicit_dn.get_clone();
    if names.is_empty() {
        names = DEFAULT_EXPLICIT_DN.iter().map(|v| v.to_string()).collect();
    }
    names
        .iter()
        .filter_map(|name| subject_field(name, form))
        .collect()
}

fn apply_subject_json(form: &CertFormSignals, subject: &Value) {
    for signal in [
        form.cn,
        form.organization,
        form.org_unit,
        form.country,
        form.state,
        form.locality,
        form.email,
    ] {
        signal.set(String::new());
    }
    let entries = subject.as_array().cloned().unwrap_or_default();
    let mut extras = Vec::new();
    for entry in entries {
        let name = entry.get("name").and_then(|v| v.as_str()).unwrap_or("");
        let value = entry.get("value").and_then(|v| v.as_str()).unwrap_or("");
        if name.is_empty() || value.is_empty() {
            continue;
        }
        match subject_signal(name, form) {
            Some(signal) if signal.get_clone().is_empty() => signal.set(value.to_string()),
            _ => extras.push(entry),
        }
    }
    if extras.is_empty() {
        form.subject_extra.set(String::new());
    } else {
        form.subject_extra
            .set(serde_json::to_string_pretty(&Value::Array(extras)).unwrap_or_default());
    }
}

fn extra_subject_entries(form: &CertFormSignals) -> Result<Vec<Value>, String> {
    let text = form.subject_extra.get_clone();
    if text.trim().is_empty() {
        return Ok(Vec::new());
    }
    let value: Value = serde_json::from_str(&text)
        .map_err(|_| "additional subject attributes must be valid JSON".to_string())?;
    let entries = value
        .as_array()
        .ok_or_else(|| "additional subject attributes must be a JSON array".to_string())?;
    let mut result = Vec::new();
    for entry in entries {
        let name = entry
            .get("name")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .trim();
        let value = entry
            .get("value")
            .and_then(|v| v.as_str())
            .unwrap_or("")
            .trim();
        if name.is_empty() {
            return Err("each additional subject attribute needs a name".to_string());
        }
        if value.is_empty() {
            continue;
        }
        result.push(json!({"name": name, "value": value}));
    }
    Ok(result)
}

fn build_subject(form: &CertFormSignals) -> Result<Vec<Value>, String> {
    let extras = extra_subject_entries(form)?;
    let mut used = vec![false; extras.len()];
    let mut result = Vec::new();
    let mut names = form.explicit_dn.get_clone();
    if names.is_empty() {
        names = DEFAULT_EXPLICIT_DN.iter().map(|v| v.to_string()).collect();
    }
    for name in names {
        if let Some(signal) = subject_signal(&name, form) {
            let value = signal.get_clone();
            if !value.trim().is_empty() {
                result.push(json!({"name": name, "value": value.trim()}));
            }
            continue;
        }
        for (index, entry) in extras.iter().enumerate() {
            if used[index] {
                continue;
            }
            if entry.get("name").and_then(|v| v.as_str()) == Some(name.as_str()) {
                used[index] = true;
                result.push(entry.clone());
                break;
            }
        }
    }
    for (index, entry) in extras.into_iter().enumerate() {
        if !used[index] {
            result.push(entry);
        }
    }
    Ok(result)
}

fn build_extensions(form: &CertFormSignals) -> Result<Value, String> {
    let mut extensions = json!({});
    let mode = form.ca_mode.get_clone();
    if mode == "ca" {
        extensions["basic_constraints"] = json!({
            "critical": form.bc_critical.get(),
            "ca": true,
            "path_length": form.path_length.get_clone().parse::<i64>().ok(),
        });
    } else if mode == "end" {
        extensions["basic_constraints"] =
            json!({"critical": form.bc_critical.get(), "ca": false, "path_length": null});
    }
    let usages = [
        (form.ku_digital.get(), "digital_signature"),
        (form.ku_encipher.get(), "key_encipherment"),
        (form.ku_key_agreement.get(), "key_agreement"),
        (form.ku_cert_sign.get(), "key_cert_sign"),
        (form.ku_crl_sign.get(), "crl_sign"),
    ]
    .iter()
    .filter(|(checked, _)| *checked)
    .map(|(_, name)| json!(name))
    .collect::<Vec<_>>();
    extensions["key_usage"] = json!({"critical": form.ku_critical.get(), "usages": usages});
    let eku = [
        (form.eku_server.get(), "serverAuth"),
        (form.eku_client.get(), "clientAuth"),
        (form.eku_code.get(), "codeSigning"),
        (form.eku_email.get(), "emailProtection"),
        (form.eku_time.get(), "timeStamping"),
        (form.eku_ocsp.get(), "OCSPSigning"),
    ]
    .iter()
    .filter(|(checked, _)| *checked)
    .map(|(_, name)| json!(name))
    .collect::<Vec<_>>();
    extensions["extended_key_usage"] = json!({"critical": form.eku_critical.get(), "usages": eku});
    let san = parse_san(&form.san_text.get_clone());
    if !san.is_empty() {
        extensions["subject_alt_name"] = json!({"critical": false, "entries": san});
    }
    if form.ski.get() {
        extensions["subject_key_identifier"] = json!({"critical": false});
    }
    if form.aki.get() {
        extensions["authority_key_identifier"] = json!({"critical": false});
    }
    if form.ocsp_staple.get() {
        extensions["tls_feature"] = json!({"critical": false, "features": ["status_request"]});
    }
    let extra = build_extra_extensions(&form.ext)?;
    if let Some(object) = extra.as_object() {
        for (key, value) in object {
            extensions[key] = value.clone();
        }
    }
    Ok(extensions)
}

fn validity_value(form: &CertFormSignals) -> Value {
    if form.no_expiration.get() {
        json!({"no_expiration": true})
    } else if form.validity_mode.get_clone() == "absolute" {
        json!({})
    } else {
        json!({
            "amount": form.validity_amount.get_clone().parse::<i64>().unwrap_or(365),
            "unit": form.validity_unit.get_clone(),
            "midnight": form.midnight.get(),
        })
    }
}

fn build_target(form: &CertFormSignals) -> Result<Value, String> {
    let subject = build_subject(form)?;
    let mut target = json!({
        "subject": subject,
        "extensions": build_extensions(form)?,
        "validity": validity_value(form),
    });
    if form.validity_mode.get_clone() == "absolute" && !form.no_expiration.get() {
        target["not_before"] = json!(form.not_before_text.get_clone());
        target["not_after"] = json!(form.not_after_text.get_clone());
    }
    Ok(target)
}

fn apply_validity_json(form: &CertFormSignals, value: &Value) {
    if value.is_null() {
        return;
    }
    let amount = value.get("amount").and_then(|v| v.as_i64());
    let unit = value.get("unit").and_then(|v| v.as_str());
    let midnight = value.get("midnight").and_then(|v| v.as_bool());
    let no_expiration = value
        .get("no_expiration")
        .and_then(|v| v.as_bool())
        .unwrap_or(false);
    if let Some(amount) = amount {
        form.validity_amount.set(amount.to_string());
    }
    if let Some(unit) = unit {
        form.validity_unit.set(unit.to_string());
    }
    if let Some(midnight) = midnight {
        form.midnight.set(midnight);
    }
    form.no_expiration.set(no_expiration);
    if !no_expiration {
        form.validity_mode.set("duration".to_string());
    }
}

fn apply_extension_spec(form: &CertFormSignals, spec: &Value) {
    load_extra_extensions(&form.ext, spec);
    if let Some(bc) = spec.get("basic_constraints") {
        if bc.get("ca").and_then(|v| v.as_bool()).unwrap_or(false) {
            form.ca_mode.set("ca".to_string());
            form.path_length.set(
                bc.get("path_length")
                    .and_then(|v| v.as_i64())
                    .map(|v| v.to_string())
                    .unwrap_or_default(),
            );
        } else if bc.get("ca").is_some() {
            form.ca_mode.set("end".to_string());
            form.path_length.set(String::new());
        }
        form.bc_critical
            .set(bc.get("critical").and_then(|v| v.as_bool()).unwrap_or(true));
    } else {
        form.ca_mode.set("none".to_string());
    }
    if let Some(ku) = spec.get("key_usage") {
        let usages = string_array(ku.get("usages"));
        form.ku_digital
            .set(usages.iter().any(|s| s == "digital_signature"));
        form.ku_encipher
            .set(usages.iter().any(|s| s == "key_encipherment"));
        form.ku_key_agreement
            .set(usages.iter().any(|s| s == "key_agreement"));
        form.ku_cert_sign
            .set(usages.iter().any(|s| s == "key_cert_sign"));
        form.ku_crl_sign.set(usages.iter().any(|s| s == "crl_sign"));
        form.ku_critical
            .set(ku.get("critical").and_then(|v| v.as_bool()).unwrap_or(true));
    }
    if let Some(eku) = spec.get("extended_key_usage") {
        let usages = string_array(eku.get("usages"));
        form.eku_server
            .set(usages.iter().any(|s| s == "serverAuth"));
        form.eku_client
            .set(usages.iter().any(|s| s == "clientAuth"));
        form.eku_code.set(usages.iter().any(|s| s == "codeSigning"));
        form.eku_email
            .set(usages.iter().any(|s| s == "emailProtection"));
        form.eku_time
            .set(usages.iter().any(|s| s == "timeStamping"));
        form.eku_ocsp.set(usages.iter().any(|s| s == "OCSPSigning"));
        form.eku_critical.set(
            eku.get("critical")
                .and_then(|v| v.as_bool())
                .unwrap_or(false),
        );
    }
    if let Some(san) = spec.get("subject_alt_name") {
        let entries = san
            .get("entries")
            .and_then(|v| v.as_array())
            .cloned()
            .unwrap_or_default();
        let text = entries
            .iter()
            .filter_map(|entry| {
                let kind = entry.get("type").and_then(|v| v.as_str()).unwrap_or("dns");
                let value = entry.get("value").and_then(|v| v.as_str()).unwrap_or("");
                if value.is_empty() {
                    None
                } else {
                    Some(format!("{}:{}", kind.to_uppercase(), value))
                }
            })
            .collect::<Vec<_>>()
            .join(", ");
        form.san_text.set(text);
    } else {
        form.san_text.set(String::new());
    }
    form.ski.set(spec.get("subject_key_identifier").is_some());
    form.aki.set(spec.get("authority_key_identifier").is_some());
    let features = spec
        .get("tls_feature")
        .and_then(|v| v.get("features"))
        .and_then(|v| v.as_array())
        .cloned()
        .unwrap_or_default();
    form.ocsp_staple.set(
        features
            .iter()
            .any(|v| v.as_str() == Some("status_request")),
    );
}

fn check(label: &'static str, value: Signal<bool>) -> View {
    view! {
        div(class="form-check") {
            input(class="form-check-input", r#type="checkbox", bind:checked=value)
            label(class="form-check-label") { (label) }
        }
    }
}

fn parse_san(text: &str) -> Vec<serde_json::Value> {
    text.split(',')
        .map(|chunk| chunk.trim())
        .filter(|chunk| !chunk.is_empty())
        .map(|chunk| {
            if let Some((prefix, value)) = chunk.split_once(':') {
                let kind = match prefix.trim().to_lowercase().as_str() {
                    "ip" => "ip",
                    "uri" => "uri",
                    "email" => "email",
                    "rid" => "rid",
                    "dns" => "dns",
                    _ => "dns",
                };
                json!({"type": kind, "value": value.trim()})
            } else {
                json!({"type": "dns", "value": chunk})
            }
        })
        .collect()
}

fn string_array(value: Option<&serde_json::Value>) -> Vec<String> {
    value
        .and_then(|v| v.as_array())
        .map(|items| {
            items
                .iter()
                .filter_map(|v| v.as_str().map(|s| s.to_string()))
                .collect()
        })
        .unwrap_or_default()
}

fn query_param(name: &str) -> Option<String> {
    let search = web_sys::window()?.location().search().ok()?;
    let search = search.trim_start_matches('?');
    for pair in search.split('&') {
        let (key, value) = pair.split_once('=').unwrap_or((pair, ""));
        if key == name {
            return Some(value.to_string());
        }
    }
    None
}