//! Quicklook plugin (condensed stats displayed in the top-left corner).

use crate::cpu_percent::cpu_percent;
use crate::fields;
use glances_core::plugin::{Decoration, Field, HistoryItem, Plugin, PluginModel, UpdateContext};
use glances_core::{Args, Config};
use serde_json::{Value, json};

pub struct QuicklookPlugin {
    pub model: PluginModel,
    pub stats_list: Vec<String>,
    pub max_cpu_display: usize,
}

const AVAILABLE_STATS_LIST: [&str; 6] = ["cpu", "mem", "swap", "load", "gpu_mem", "gpu_proc"];
const DEFAULT_STATS_LIST: [&str; 3] = ["cpu", "mem", "load"];

impl QuicklookPlugin {
    pub fn new(config: &Config, args: &Args) -> Self {
        let fields = fields! {
            "cpu" => Field::new("CPU percent usage").unit("percent"),
            "percpu" => Field::new("PERCPU percent usage").unit("percent"),
            "mem" => Field::new("MEM percent usage").unit("percent"),
            "swap" => Field::new("SWAP percent usage").unit("percent"),
            "load" => Field::new("LOAD percent usage").unit("percent").alert(),
            "cpu_log_core" => Field::new("Number of logical CPU core").unit("number"),
            "cpu_phys_core" => Field::new("Number of physical CPU core").unit("number"),
            "cpu_name" => Field::new("CPU name"),
            "cpu_hz_current" => Field::new("CPU current frequency").unit("hertz"),
            "cpu_hz" => Field::new("CPU max frequency").unit("hertz"),
            "gpu_mem" => Field::new("Average GPU Memory consumption").unit("percent"),
            "gpu_proc" => Field::new("Average GPU Processor consumption").unit("percent"),
        };
        let items_history = vec![
            HistoryItem::new("cpu", "CPU percent usage"),
            HistoryItem::new("percpu", "PERCPU percent usage"),
            HistoryItem::new("mem", "MEM percent usage"),
            HistoryItem::new("swap", "SWAP percent usage"),
            HistoryItem::new("load", "LOAD percent usage"),
            HistoryItem::new("gpu_mem", "GPU memory percent usage"),
            HistoryItem::new("gpu_proc", "GPU processor percent usage"),
        ];
        let model = PluginModel::new(
            "quicklook",
            fields,
            items_history,
            json!({}),
            config,
            args.time.unwrap_or(2.0),
            args.disable_history,
            args.disable_config_exec,
        );
        let stats_list = model.get_conf_value("list", "");
        let mut stats_list: Vec<String> = if stats_list.is_empty() {
            DEFAULT_STATS_LIST.iter().map(|s| s.to_string()).collect()
        } else {
            stats_list
        };
        if stats_list
            .iter()
            .any(|s| !AVAILABLE_STATS_LIST.contains(&s.as_str()))
        {
            stats_list = DEFAULT_STATS_LIST.iter().map(|s| s.to_string()).collect();
        }
        let max_cpu_display = config.get_int_value("percpu", "max_cpu_display", 4).max(0) as usize;
        Self {
            model,
            stats_list,
            max_cpu_display,
        }
    }

    fn mhz_to_hz(value: Option<f64>) -> Option<f64> {
        value.map(|v| v * 1_000_000.0)
    }
}

impl Plugin for QuicklookPlugin {
    fn name(&self) -> &str {
        "quicklook"
    }

    fn model(&self) -> &PluginModel {
        &self.model
    }

    fn model_mut(&mut self) -> &mut PluginModel {
        &mut self.model
    }

    fn collect(&mut self, _ctx: &mut UpdateContext) -> anyhow::Result<Value> {
        let mut stats = serde_json::Map::new();
        let (info, cpu_value, percpu_values) = {
            let mut state = cpu_percent().lock().unwrap();
            let info = state.get_info();
            let cpu = state.get_cpu();
            let percpu = state.get_percpu().to_vec();
            (info, cpu, percpu)
        };
        stats.insert("cpu_name".to_string(), json!(info.cpu_name));
        stats.insert(
            "cpu_hz_current".to_string(),
            json!(Self::mhz_to_hz(info.cpu_hz_current)),
        );
        stats.insert("cpu_hz".to_string(), json!(Self::mhz_to_hz(info.cpu_hz)));
        stats.insert("cpu".to_string(), json!(cpu_value));
        stats.insert("percpu".to_string(), Value::Array(percpu_values));

        let meminfo = crate::collectors::read_meminfo();
        let total = meminfo.get("MemTotal").copied().unwrap_or(0) as f64;
        let available = meminfo.get("MemAvailable").copied().unwrap_or(0) as f64;
        stats.insert(
            "mem".to_string(),
            json!(if total > 0.0 {
                ((total - available) / total * 100.0 * 10.0).round() / 10.0
            } else {
                0.0
            }),
        );
        let swap_total = meminfo.get("SwapTotal").copied().unwrap_or(0);
        let swap_free = meminfo.get("SwapFree").copied().unwrap_or(0);
        stats.insert(
            "swap".to_string(),
            json!(if swap_total > 0 {
                (((swap_total - swap_free) as f64 * 100.0 / swap_total as f64) * 10.0).round()
                    / 10.0
            } else {
                0.0
            }),
        );

        let log_core = crate::collectors::logical_core_count();
        stats.insert("cpu_log_core".to_string(), json!(log_core));
        stats.insert(
            "cpu_phys_core".to_string(),
            json!(crate::collectors::physical_core_count()),
        );
        let load = crate::collectors::read_loadavg().map(|(_, _, min15)| {
            if log_core > 0 {
                min15 / log_core as f64 * 100.0
            } else {
                0.0
            }
        });
        stats.insert("load".to_string(), json!(load));
        stats.insert("gpu_mem".to_string(), Value::Null);
        stats.insert("gpu_proc".to_string(), Value::Null);

        Ok(Value::Object(stats))
    }

    fn update_views(&mut self) {
        let key = self.get_key();
        self.model.update_views(key);
        let stats_list = self.stats_list.clone();
        for stat_key in &stats_list {
            if let Some(value) = self.model.stats.get(stat_key).and_then(Value::as_f64) {
                let decoration = self.model.get_alert(
                    value,
                    0.0,
                    100.0,
                    true,
                    false,
                    Some(stat_key),
                    None,
                    false,
                );
                self.model.set_view_decoration(None, stat_key, decoration);
            }
        }
        // Store the list of stats to display and the per-CPU decorations.
        self.model
            .views
            .insert("list".to_string(), json!(stats_list));
        let mut percpu_decoration = serde_json::Map::new();
        if let Some(percpu) = self.model.stats.get("percpu").and_then(Value::as_array) {
            for cpu in percpu {
                let number = cpu
                    .get("cpu_number")
                    .map(glances_core::py_str)
                    .unwrap_or_default();
                let total = cpu.get("total").and_then(Value::as_f64).unwrap_or(0.0);
                percpu_decoration.insert(
                    number,
                    json!(decoration_for_percent(&self.model, total).name()),
                );
            }
            if percpu.len() > self.max_cpu_display && self.max_cpu_display > 0 {
                let mut hidden: Vec<f64> = percpu
                    .iter()
                    .filter_map(|cpu| cpu.get("total").and_then(Value::as_f64))
                    .collect();
                hidden.sort_by(|a, b| b.partial_cmp(a).unwrap_or(std::cmp::Ordering::Equal));
                let hidden = &hidden[self.max_cpu_display.min(hidden.len())..];
                if !hidden.is_empty() {
                    let mean = hidden.iter().sum::<f64>() / hidden.len() as f64;
                    percpu_decoration.insert(
                        "other".to_string(),
                        json!(decoration_for_percent(&self.model, mean).name()),
                    );
                }
            }
        }
        self.model.views.insert(
            "percpu_decoration".to_string(),
            Value::Object(percpu_decoration),
        );
    }

    fn display_curse(&self) -> bool {
        true
    }

    fn render(&mut self, ctx: &glances_core::RenderContext) -> Vec<glances_core::StatLine> {
        let mut ret = Vec::new();
        let s = &self.model.stats;
        if !s.is_object() || ctx.max_width == 0 {
            return ret;
        }
        // System information: CPU name + frequency.
        let freq = match (
            s.get("cpu_hz_current").and_then(Value::as_f64),
            s.get("cpu_hz").and_then(Value::as_f64),
        ) {
            (Some(current), Some(max)) => format!(" {:.2}/{:.2}GHz", current / 1e9, max / 1e9),
            (Some(current), None) => format!(" {:.2}GHz", current / 1e9),
            _ => String::new(),
        };
        let cpu_name = s.get("cpu_name").and_then(Value::as_str).unwrap_or("");
        let name = if (ctx.max_width as i64 - freq.len() as i64 + 7) > 0 {
            format!(
                "{:<width$}",
                cpu_name,
                width = ctx.max_width - freq.len() + 7
            )
        } else if freq.is_empty() {
            String::new()
        } else {
            "Frequency".to_string()
        };
        ret.push(self.model.curse_add_line(
            name.clone(),
            glances_core::Decoration::Default,
            false,
            false,
            false,
        ));
        ret.push(self.model.curse_add_line(
            freq.clone(),
            glances_core::Decoration::Default,
            false,
            false,
            false,
        ));
        ret.push(self.model.curse_new_line());

        let bar_size = std::cmp::max(
            name.len().saturating_add(freq.len()).saturating_sub(7),
            ctx.max_width.saturating_sub(9),
        )
        .max(10);
        let bar_char = self
            .model
            .get_conf_value("bar_char", "")
            .first()
            .cloned()
            .unwrap_or_else(|| "|".to_string());

        let mut lines: Vec<Vec<glances_core::StatLine>> = Vec::new();
        let mut push_line = |msg: String,
                             bar_key: &str,
                             percent: f64,
                             decoration: glances_core::Decoration| {
            let bar = glances_core::units::bar_percent(percent, bar_size, &bar_char, true);
            lines.push(vec![
                self.model.curse_add_line(
                    msg,
                    glances_core::Decoration::Default,
                    false,
                    false,
                    false,
                ),
                self.model
                    .curse_add_line("[", glances_core::Decoration::Bold, false, false, false),
                self.model
                    .curse_add_line(bar, decoration, false, false, false),
                self.model
                    .curse_add_line("]", glances_core::Decoration::Bold, false, false, false),
                self.model.curse_add_line(
                    "  ",
                    glances_core::Decoration::Default,
                    false,
                    false,
                    false,
                ),
            ]);
            let _ = bar_key;
        };

        let stats_list = self.stats_list.clone();
        for key in &stats_list {
            if key == "cpu" && ctx.runtime.percpu {
                if let Some(percpu) = s.get("percpu").and_then(Value::as_array) {
                    let mut sorted = percpu.clone();
                    if sorted.len() > self.max_cpu_display {
                        sorted.sort_by(|a, b| {
                            b.get("total")
                                .and_then(Value::as_f64)
                                .unwrap_or(0.0)
                                .partial_cmp(&a.get("total").and_then(Value::as_f64).unwrap_or(0.0))
                                .unwrap_or(std::cmp::Ordering::Equal)
                        });
                    }
                    for cpu in sorted.iter().take(self.max_cpu_display) {
                        let cpu_id = cpu.get("cpu_number").and_then(Value::as_i64).unwrap_or(0);
                        let total = cpu.get("total").and_then(Value::as_f64).unwrap_or(0.0);
                        let msg = if cpu_id < 10 {
                            format!("{:<3}{cpu_id} ", key.to_uppercase())
                        } else {
                            format!("{cpu_id:4} ")
                        };
                        let decoration = self.decoration_for_percpu(cpu_id);
                        push_line(msg, key, total, decoration);
                    }
                    if percpu.len() > self.max_cpu_display {
                        let hidden: Vec<f64> = sorted
                            .iter()
                            .skip(self.max_cpu_display)
                            .filter_map(|cpu| cpu.get("total").and_then(Value::as_f64))
                            .collect();
                        let mean = if hidden.is_empty() {
                            0.0
                        } else {
                            hidden.iter().sum::<f64>() / hidden.len() as f64
                        };
                        let decoration = self.decoration_for_percpu(-1);
                        push_line(
                            format!("{:<3}* ", key.to_uppercase()),
                            key,
                            mean,
                            decoration,
                        );
                    }
                }
            } else if let Some(value) = s.get(key).and_then(Value::as_f64) {
                let decoration = self.model.view_decoration(None, key);
                push_line(
                    format!("{:<4} ", key.to_uppercase()),
                    key,
                    value,
                    decoration,
                );
            }
        }
        for line in lines {
            ret.extend(line);
            ret.push(self.model.curse_new_line());
        }
        ret.pop();
        ret
    }
}

impl QuicklookPlugin {
    fn decoration_for_percpu(&self, cpu_id: i64) -> glances_core::Decoration {
        let key = if cpu_id < 0 {
            "other".to_string()
        } else {
            cpu_id.to_string()
        };
        match self.model.get_view(None, "percpu_decoration", &key) {
            Value::String(name) => glances_core::Decoration::from_name(&name),
            _ => glances_core::Decoration::Default,
        }
    }
}

/// Return the style for a CPU percentage without the get_alert side effects.
fn decoration_for_percent(model: &PluginModel, percent: f64) -> Decoration {
    let stat_name = model.get_stat_name(Some("cpu"), None).to_lowercase();
    let critical = model.get_limit("critical", &stat_name).unwrap_or(0.0);
    let warning = model.get_limit("warning", &stat_name).unwrap_or(0.0);
    let careful = model.get_limit("careful", &stat_name).unwrap_or(0.0);
    if critical > 0.0 && percent >= critical {
        Decoration::Critical
    } else if warning > 0.0 && percent >= warning {
        Decoration::Warning
    } else if careful > 0.0 && percent >= careful {
        Decoration::Careful
    } else {
        Decoration::Default
    }
}