//! Live game page: table view over the websocket.
use std::cell::Cell;
use std::rc::Rc;

use sycamore::prelude::*;

use crate::components::card::{card_back, card_img};
use crate::components::summary::{hand_summary_modal, summary_rows};
use crate::components::toast::toast;
use crate::model::{card_label, GameView, MoveView, PlayerView, Scores, ServerMessage};
use crate::ws::{self, GameSocket};

fn send_play(socket: Signal<Option<GameSocket>>, card: String, capture: Option<Vec<String>>) {
    if let Some(s) = socket.get_clone() {
        s.play(&card, capture);
    }
}

/// Panel for one player seat (name, team, hidden card count, stats).
fn seat_panel(game: GameView, seat: usize, position: &'static str) -> View {
    let Some(player) = game.players.iter().find(|p| p.seat == seat).cloned() else {
        return view! {};
    };
    let active = game.phase == "playing" && game.turn == seat;
    let cls = format!(
        "seat seat-{position}{}",
        if active { " active" } else { "" }
    );
    let name = player.name.clone();
    let team = player.team.clone();
    let captured = player.captured_count;
    let scope = player.scope;
    let backs = (0..player.cards_left)
        .map(|_| card_back("mini"))
        .collect::<Vec<_>>();
    view! {
        div(class=cls) {
            div(class="seat-name") {
                (name)
                span(class="team-badge") { "Team " (team) }
            }
            div(class="seat-cards") { (backs) }
            div(class="seat-stats") {
                (captured) " captured · " (scope) " scope"
            }
        }
    }
}

/// The last-move announcement strip.
fn move_banner(mv: MoveView) -> View {
    let name = mv.name.clone();
    let action = if mv.captured.is_empty() {
        "played"
    } else {
        "capturing"
    };
    let played = card_img(mv.card.clone(), "move-card");
    let captured = mv
        .captured
        .iter()
        .map(|c| card_img(c.clone(), "move-card"))
        .collect::<Vec<_>>();
    let scopa = mv.scopa.then(|| view! { span(class="scopa-badge") { "Scopa!" } });
    view! {
        div(class="move-banner") {
            strong { (name) }
            span { " " (action) " " }
            (played)
            (captured)
            (scopa)
        }
    }
}

/// Signals shared by the websocket connection and its reconnect attempts.
#[derive(Clone, Copy)]
struct ConnCtx {
    socket: Signal<Option<GameSocket>>,
    game: Signal<Option<GameView>>,
    over: Signal<Option<(Scores, Option<String>)>>,
    error: Signal<Option<String>>,
    closed: Signal<bool>,
    /// Reconnect attempts exhausted; only a manual retry resumes.
    gave_up: Signal<bool>,
    /// The server closed the connection deliberately (auth or game gone);
    /// retrying is pointless.
    fatal: Signal<bool>,
    attempts: Signal<u32>,
    capture_choice: Signal<Option<(String, Vec<Vec<String>>)>>,
    selected: Signal<Option<String>>,
}

/// Reconnect attempts: 1s, 2s, 4s, … capped at 30s, at most this many.
const MAX_RECONNECT_ATTEMPTS: u32 = 10;

fn backoff_ms(attempt: u32) -> u32 {
    (1000u32 << attempt.min(5)).min(30_000)
}

/// Connect the game websocket, wiring state updates and reconnects.
///
/// The server pushes a full state snapshot on connect, so a reconnect is
/// also a resync: no client-side state merging is needed.
fn start_connect(id: Rc<String>, ctx: ConnCtx, alive: Rc<Cell<bool>>) {
    let on_message = {
        let alive = alive.clone();
        move |msg: ServerMessage| {
            if !alive.get() {
                // The page is unmounted; its signals are disposed.
                return;
            }
            match msg {
                ServerMessage::State { game: g } => {
                    ctx.capture_choice.set(None);
                    ctx.selected.set(None);
                    // A received state proves the (re)connection works.
                    ctx.attempts.set(0);
                    ctx.gave_up.set(false);
                    ctx.closed.set(false);
                    ctx.game.set(Some(g));
                }
                ServerMessage::GameOver { scores, winner } => {
                    ctx.over.set(Some((scores, winner)))
                }
                ServerMessage::Error { message, .. } => ctx.error.set(Some(message)),
            }
        }
    };
    let on_close = {
        let id = id.clone();
        let alive = alive.clone();
        move |code: Option<u16>| {
            if !alive.get() {
                return;
            }
            ctx.closed.set(true);
            match code {
                Some(4401) => {
                    ctx.fatal.set(true);
                    ctx.error
                        .set(Some("Session expired — please log in again.".to_string()));
                }
                Some(4403) | Some(4404) => {
                    ctx.fatal.set(true);
                    ctx.error
                        .set(Some("This game is no longer available.".to_string()));
                }
                _ => schedule_retry(id.clone(), ctx, alive.clone()),
            }
        }
    };
    match ws::connect(&id, on_message, on_close) {
        Some(s) => ctx.socket.set(Some(s)),
        // WebSocket::open failed synchronously: treat as a transient loss.
        None if alive.get() => {
            ctx.closed.set(true);
            schedule_retry(id, ctx, alive);
        }
        None => {}
    }
}

/// Retry `start_connect` with exponential backoff, unless we gave up.
fn schedule_retry(id: Rc<String>, ctx: ConnCtx, alive: Rc<Cell<bool>>) {
    let attempt = ctx.attempts.get();
    if attempt >= MAX_RECONNECT_ATTEMPTS {
        ctx.gave_up.set(true);
        return;
    }
    ctx.attempts.set(attempt + 1);
    gloo_timers::callback::Timeout::new(backoff_ms(attempt), move || {
        if alive.get() {
            start_connect(id, ctx, alive);
        }
    })
    .forget();
}

/// Slim banner shown over the table while the socket is down.
fn conn_banner(
    closed: bool,
    gave_up: bool,
    fatal: bool,
    has_game: bool,
    reconnect: Rc<dyn Fn()>,
) -> View {
    if !closed || !has_game {
        return view! {};
    }
    if fatal {
        view! {
            div(class="conn-banner") {
                "Connection closed by the server. "
                a(href="/") { "Back to lobby" }
            }
        }
    } else if gave_up {
        view! {
            div(class="conn-banner") {
                "Connection lost."
                button(class="button", on:click=move |_| reconnect()) { "Retry now" }
                a(href="/") { "Back to lobby" }
            }
        }
    } else {
        view! {
            div(class="conn-banner") { "Connection lost — reconnecting…" }
        }
    }
}

#[component(inline_props)]
pub fn GamePage(id: String) -> View {
    let game = create_signal(Option::<GameView>::None);
    let error = create_signal(Option::<String>::None);
    let capture_choice = create_signal(Option::<(String, Vec<Vec<String>>)>::None);
    let selected = create_signal(Option::<String>::None);
    let over = create_signal(Option::<(Scores, Option<String>)>::None);
    let closed = create_signal(false);
    let gave_up = create_signal(false);
    let fatal = create_signal(false);
    let attempts = create_signal(0u32);
    let socket = create_signal(Option::<GameSocket>::None);
    // Ticking clock driving the hand-end countdown display.
    let now = create_signal(js_sys::Date::now());
    let ticker = gloo_timers::callback::Interval::new(500, move || now.set(js_sys::Date::now()));

    // Stops the ticker and any pending reconnect once the page unmounts.
    let alive = Rc::new(Cell::new(true));
    on_cleanup({
        let alive = alive.clone();
        move || {
            alive.set(false);
            drop(ticker);
        }
    });

    let id = Rc::new(id);
    let ctx = ConnCtx {
        socket,
        game,
        over,
        error,
        closed,
        gave_up,
        fatal,
        attempts,
        capture_choice,
        selected,
    };
    start_connect(id.clone(), ctx, alive.clone());
    let reconnect: Rc<dyn Fn()> = Rc::new(move || {
        ctx.attempts.set(0);
        ctx.gave_up.set(false);
        ctx.closed.set(false);
        start_connect(id.clone(), ctx, alive.clone());
    });

    // Clicking a card in the player's own hand.
    let on_hand_card = move |code: String| {
        if closed.get() {
            // A dead socket would swallow the play silently.
            return;
        }
        let Some(g) = game.get_clone() else { return };
        if g.your_turn != Some(true) {
            return;
        }
        let options = g
            .legal_moves
            .as_ref()
            .and_then(|m| m.get(&code))
            .cloned();
        match options {
            None => send_play(socket, code, None),
            Some(mut opts) if opts.len() == 1 => {
                send_play(socket, code, Some(opts.remove(0)))
            }
            Some(opts) => capture_choice.set(Some((code, opts))),
        }
    };

    let reconnect_banner = reconnect.clone();
    view! {
        div(class="game-page") {
            (toast(error))
            (move || conn_banner(
                closed.get(),
                gave_up.get(),
                fatal.get(),
                game.get_clone().is_some(),
                reconnect_banner.clone(),
            ))
            (move || match game.get_clone() {
                None => {
                    if fatal.get() {
                        view! {
                            div(class="panel status-panel") {
                                p { "Connection closed." }
                                p { a(href="/") { "Back to lobby" } }
                            }
                        }
                    } else if gave_up.get() {
                        let reconnect = reconnect.clone();
                        view! {
                            div(class="panel status-panel") {
                                p { "Connection lost." }
                                p {
                                    button(class="button primary", on:click=move |_| reconnect()) {
                                        "Retry now"
                                    }
                                }
                                p { a(href="/") { "Back to lobby" } }
                            }
                        }
                    } else {
                        let status = if closed.get() {
                            "Connection lost — reconnecting…"
                        } else {
                            "Connecting to the game…"
                        };
                        view! {
                            div(class="panel status-panel") {
                                p { (status) }
                                p { a(href="/") { "Back to lobby" } }
                            }
                        }
                    }
                }
                Some(g) if g.phase == "lobby" => lobby_view(g),
                Some(g) => table_view(g, on_hand_card, selected, now),
            })
            (move || capture_choice.get_clone().map(|(card, options)| {
                capture_picker(card, options, socket, capture_choice)
            }))
            (move || match game.get_clone() {
                Some(g) if g.phase == "hand_end" => hand_summary_modal(g, socket, now),
                _ => view! {},
            })
            (move || game_over_view(over.get_clone(), game.get_clone()))
        }
    }
}

/// Lobby view while waiting for the fourth player.
fn lobby_view(game: GameView) -> View {
    let seats_open = 4usize.saturating_sub(game.players.len());
    let join_code = game.join_code.clone();
    let players = game
        .players
        .iter()
        .map(|p| {
            let name = p.name.clone();
            let seat = p.seat;
            let team = p.team.clone();
            view! {
                li {
                    strong { (name) }
                    span { " (seat " (seat) ", team " (team) ")" }
                }
            }
        })
        .collect::<Vec<_>>();
    view! {
        div(class="panel status-panel") {
            h2 { "Waiting for players" }
            p { "Share this join code:" }
            p(class="join-code") { (join_code) }
            ul(class="roster") { (players) }
            p { (seats_open) " seat(s) still open" }
            p { a(href="/") { "Back to lobby" } }
        }
    }
}

fn player_for_seat(game: &GameView, seat: usize) -> Option<PlayerView> {
    game.players.iter().find(|p| p.seat == seat).cloned()
}

/// The main table view.
fn table_view(
    game: GameView,
    on_hand_card: impl Fn(String) + Copy + 'static,
    selected: Signal<Option<String>>,
    now: Signal<f64>,
) -> View {
    // Own seat: the only player entry carrying a hand.
    let viewer_seat = game
        .players
        .iter()
        .find(|p| p.hand.is_some())
        .map(|p| p.seat)
        .unwrap_or(0);
    let left = seat_panel(game.clone(), (viewer_seat + 1) % 4, "left");
    let top = seat_panel(game.clone(), (viewer_seat + 2) % 4, "top");
    let right = seat_panel(game.clone(), (viewer_seat + 3) % 4, "right");
    let my_turn = game.your_turn == Some(true);
    let turn_note = if game.phase == "finished" {
        "Match finished".to_string()
    } else if game.phase == "hand_end" {
        "Hand finished".to_string()
    } else if my_turn {
        "Your turn".to_string()
    } else {
        let name = player_for_seat(&game, game.turn)
            .map(|p| p.name)
            .unwrap_or_default();
        format!("{name}'s turn")
    };
    let turn_cls = if my_turn { "turn-note you" } else { "turn-note" };
    let countdown = game.turn_deadline.as_ref().map(|deadline| {
        // A dynamic closure so only the ticking number re-renders.
        let deadline_ms = js_sys::Date::parse(deadline);
        view! {
            span(class="turn-timer") {
                "Auto-play in "
                (move || {
                    ((deadline_ms - now.get_clone()) / 1000.0).ceil().max(0.0) as i32
                })
                "s"
            }
        }
    });

    let scores = game.scores.unwrap_or(Scores { a: 0, b: 0 });
    let table_cards = game
        .table
        .iter()
        .map(|c| card_img(c.clone(), "table-card"))
        .collect::<Vec<_>>();
    let empty_table = game.table.is_empty().then(|| view! {
        p(class="table-empty") { "Empty table" }
    });
    let banner = game.last_move.clone().map(move_banner);
    let hand_number = game.hand_number;
    let target_score = game.target_score;

    let viewer = player_for_seat(&game, viewer_seat);
    let my_captured = viewer.as_ref().map(|p| p.captured_count).unwrap_or(0);
    let my_scope = viewer.as_ref().map(|p| p.scope).unwrap_or(0);
    let hand = viewer.and_then(|p| p.hand).unwrap_or_default();
    let current_selection = selected.get_clone();
    let hand_cards = hand
        .into_iter()
        .map(|code| {
            let is_selected = current_selection.as_deref() == Some(code.as_str());
            let cls = if is_selected {
                "hand-slot selected"
            } else {
                "hand-slot"
            };
            let card_view = card_img(code.clone(), "hand-card");
            view! {
                button(class=cls, on:click=move |_| {
                    if my_turn {
                        on_hand_card(code.clone());
                    }
                }) { (card_view) }
            }
        })
        .collect::<Vec<_>>();
    let hint = my_turn.then(|| view! {
        p(class="hint") {
            "Click a card to play it. If it can capture in several ways you "
            "will be asked to choose."
        }
    });

    view! {
        div(class="table-wrap") {
            div(class="hud") {
                a(href="/") { "← Lobby" }
                span { "Hand " (hand_number) }
                span(class="hud-scores") {
                    "Team A " (scores.a) " — " (scores.b) " Team B (target "
                    (target_score) ")"
                }
                span(class=turn_cls) { (turn_note) }
                (countdown)
            }
            div(class="table-grid") {
                (top)
                (left)
                div(class="center") {
                    (banner)
                    div(class="table-cards") {
                        (table_cards)
                        (empty_table)
                    }
                }
                (right)
                div(class="seat-bottom") {
                    div(class="seat-stats own-stats") {
                        (my_captured) " captured · " (my_scope) " scope"
                    }
                    div(class="hand") { (hand_cards) }
                    (hint)
                }
            }
        }
    }
}

/// Popup listing the legal captures for a selected card.
fn capture_picker(
    card: String,
    options: Vec<Vec<String>>,
    socket: Signal<Option<GameSocket>>,
    capture_choice: Signal<Option<(String, Vec<Vec<String>>)>>,
) -> View {
    let title = format!("Capture with {}", card_label(&card));
    let option_views = options
        .into_iter()
        .map(|capture| {
            let played_card = card.clone();
            let cards = capture
                .iter()
                .map(|c| card_img(c.clone(), "mini"))
                .collect::<Vec<_>>();
            view! {
                button(class="capture-option", on:click=move |_| {
                    send_play(socket, played_card.clone(), Some(capture.clone()));
                    capture_choice.set(None);
                }) { (cards) }
            }
        })
        .collect::<Vec<_>>();
    view! {
        div(class="overlay") {
            div(class="picker") {
                h3 { (title) }
                div(class="capture-options") { (option_views) }
                button(class="button", on:click=move |_| capture_choice.set(None)) { "Cancel" }
            }
        }
    }
}

/// End-of-match overlay.
fn game_over_view(over: Option<(Scores, Option<String>)>, game: Option<GameView>) -> View {
    let result = over.or_else(|| {
        game.clone()
            .filter(|g| g.phase == "finished")
            .map(|g| (g.scores.unwrap_or(Scores { a: 0, b: 0 }), g.winner))
    });
    match result {
        None => view! {},
        Some((scores, winner)) => {
            let winner = winner.unwrap_or_else(|| "?".to_string());
            let line = format!("Team {winner} wins {} – {}", scores.a, scores.b);
            // Explain the final hand's scoring before the result.
            let final_summary = game
                .and_then(|g| g.last_hand)
                .map(|s| {
                    let rows = summary_rows(s);
                    view! { (rows) }
                });
            view! {
                div(class="overlay") {
                    div(class="picker summary-panel") {
                        h2 { "Match over" }
                        (final_summary)
                        p(class="final-score") { (line) }
                        div(class="gameover-actions") {
                            a(class="button primary", href="/") { "Back to lobby" }
                            a(class="button", href="/history") { "My matches" }
                        }
                    }
                }
            }
        }
    }
}