//! HUD Application
//!
//! The main GTK4 application for the HUD overlay.
//! Uses gtk4-layer-shell to create an always-visible overlay.

use crate::battery::BatteryStatus;
use crate::state::{SessionState, SharedState};
use crate::time_display::TimeDisplay;
use crate::volume::VolumeStatus;
use gtk4::glib;
use gtk4::prelude::*;
use gtk4_layer_shell::{Edge, Layer, LayerShell};
use shepherd_api::Command;
use shepherd_ipc::IpcClient;
use std::cell::RefCell;
use std::path::PathBuf;
use std::rc::Rc;
use std::time::Duration;
use tokio::runtime::Runtime;

/// The HUD application
pub struct HudApp {
    app: gtk4::Application,
    socket_path: PathBuf,
    anchor: String,
    height: i32,
}

impl HudApp {
    pub fn new(socket_path: PathBuf, anchor: String, height: i32) -> Self {
        let app = gtk4::Application::builder()
            .application_id("org.shepherd.hud")
            .build();

        Self {
            app,
            socket_path,
            anchor,
            height,
        }
    }

    pub fn run(&self) -> i32 {
        let socket_path = self.socket_path.clone();
        let anchor = self.anchor.clone();
        let height = self.height;

        self.app.connect_activate(move |app| {
            let state = SharedState::new();
            let window = build_hud_window(app, &anchor, height, state.clone());

            // Start the IPC event listener
            let state_clone = state.clone();
            let socket_clone = socket_path.clone();
            std::thread::spawn(move || {
                if let Err(e) = run_event_loop(socket_clone, state_clone) {
                    tracing::error!("Event loop error: {}", e);
                }
            });

            // Start periodic updates for battery/volume
            start_metrics_updates(state.clone());

            // Subscribe to state changes
            let window_clone = window.clone();
            let state_clone = state.clone();
            glib::timeout_add_local(Duration::from_millis(100), move || {
                let session_state = state_clone.session_state();
                let visible = session_state.is_visible();
                window_clone.set_visible(visible);
                glib::ControlFlow::Continue
            });

            window.present();
        });

        self.app.run().into()
    }
}

fn build_hud_window(
    app: &gtk4::Application,
    anchor: &str,
    height: i32,
    state: SharedState,
) -> gtk4::ApplicationWindow {
    let window = gtk4::ApplicationWindow::builder()
        .application(app)
        .default_height(height)
        .decorated(false)
        .build();

    // Initialize layer shell
    window.init_layer_shell();
    window.set_layer(Layer::Overlay);
    window.set_namespace("shepherd-hud");

    // Remove all margins from the layer-shell surface
    window.set_margin(Edge::Top, 0);
    window.set_margin(Edge::Bottom, 0);
    window.set_margin(Edge::Left, 0);
    window.set_margin(Edge::Right, 0);

    // Set anchors based on position
    match anchor {
        "bottom" => {
            window.set_anchor(Edge::Bottom, true);
            window.set_anchor(Edge::Left, true);
            window.set_anchor(Edge::Right, true);
        }
        _ => {
            // Default to top
            window.set_anchor(Edge::Top, true);
            window.set_anchor(Edge::Left, true);
            window.set_anchor(Edge::Right, true);
        }
    }

    // Set exclusive zone so other windows don't overlap
    window.set_exclusive_zone(height);

    // Load CSS
    load_css();

    // Build the HUD content
    let content = build_hud_content(state);
    window.set_child(Some(&content));

    window
}

fn build_hud_content(state: SharedState) -> gtk4::Box {
    let container = gtk4::Box::builder()
        .orientation(gtk4::Orientation::Horizontal)
        .spacing(16)
        .hexpand(true)
        .build();

    container.add_css_class("hud-bar");

    // Left section: App name and time
    let left_box = gtk4::Box::builder()
        .orientation(gtk4::Orientation::Horizontal)
        .spacing(12)
        .hexpand(true)
        .halign(gtk4::Align::Start)
        .build();

    let app_label = gtk4::Label::new(Some("No session"));
    app_label.add_css_class("app-name");
    left_box.append(&app_label);

    let time_display = TimeDisplay::new();
    left_box.append(&time_display);

    container.append(&left_box);

    // Center section: Warning banner (hidden by default)
    let warning_box = gtk4::Box::builder()
        .orientation(gtk4::Orientation::Horizontal)
        .spacing(8)
        .halign(gtk4::Align::Center)
        .visible(false)
        .build();

    let warning_icon = gtk4::Image::from_icon_name("dialog-warning-symbolic");
    warning_icon.set_pixel_size(20);
    warning_box.append(&warning_icon);

    let warning_label = gtk4::Label::new(Some("Time running out!"));
    warning_label.add_css_class("warning-text");
    warning_box.append(&warning_label);

    warning_box.add_css_class("warning-banner");
    container.append(&warning_box);

    // Right section: System indicators and close button
    let right_box = gtk4::Box::builder()
        .orientation(gtk4::Orientation::Horizontal)
        .spacing(8)
        .halign(gtk4::Align::End)
        .build();

    // Volume indicator
    let volume_button = gtk4::Button::builder()
        .icon_name("audio-volume-medium-symbolic")
        .has_frame(false)
        .build();
    volume_button.add_css_class("indicator-button");
    volume_button.connect_clicked(|_| {
        if let Err(e) = VolumeStatus::toggle_mute() {
            tracing::error!("Failed to toggle mute: {}", e);
        }
    });
    right_box.append(&volume_button);

    // Battery indicator
    let battery_box = gtk4::Box::builder()
        .orientation(gtk4::Orientation::Horizontal)
        .spacing(4)
        .build();

    let battery_icon = gtk4::Image::from_icon_name("battery-good-symbolic");
    battery_icon.set_pixel_size(20);
    battery_box.append(&battery_icon);

    let battery_label = gtk4::Label::new(Some("--%"));
    battery_label.add_css_class("battery-label");
    battery_box.append(&battery_label);

    right_box.append(&battery_box);

    // Pause button
    let pause_button = gtk4::Button::builder()
        .icon_name("media-playback-pause-symbolic")
        .has_frame(false)
        .tooltip_text("Pause session")
        .build();
    pause_button.add_css_class("control-button");

    let state_for_pause = state.clone();
    pause_button.connect_clicked(move |btn| {
        let session_state = state_for_pause.session_state();
        if let Some(session_id) = session_state.session_id() {
            // Toggle pause state - this would need to send command to daemon
            // For now, just log
            tracing::info!("Pause toggled for session {}", session_id);
        }
        // Toggle icon
        let icon_name = btn.icon_name().unwrap_or_default();
        if icon_name == "media-playback-pause-symbolic" {
            btn.set_icon_name("media-playback-start-symbolic");
            btn.set_tooltip_text(Some("Resume session"));
        } else {
            btn.set_icon_name("media-playback-pause-symbolic");
            btn.set_tooltip_text(Some("Pause session"));
        }
    });
    right_box.append(&pause_button);

    // Close button
    let close_button = gtk4::Button::builder()
        .icon_name("window-close-symbolic")
        .has_frame(false)
        .tooltip_text("End session")
        .build();
    close_button.add_css_class("close-button");

    let state_for_close = state.clone();
    close_button.connect_clicked(move |_| {
        let session_state = state_for_close.session_state();
        if let Some(session_id) = session_state.session_id() {
            tracing::info!("Requesting end session for {}", session_id);
            // Send StopCurrent command to daemon
            let socket_path = std::env::var("SHEPHERD_SOCKET")
                .unwrap_or_else(|_| "./dev-runtime/shepherd.sock".to_string());
            std::thread::spawn(move || {
                let rt = Runtime::new().expect("Failed to create runtime");
                rt.block_on(async {
                    match IpcClient::connect(std::path::PathBuf::from(&socket_path)).await {
                        Ok(mut client) => {
                            let cmd = Command::StopCurrent {
                                mode: shepherd_api::StopMode::Graceful,
                            };
                            if let Err(e) = client.send(cmd).await {
                                tracing::error!("Failed to send StopCurrent: {}", e);
                            }
                        }
                        Err(e) => {
                            tracing::error!("Failed to connect to daemon: {}", e);
                        }
                    }
                });
            });
        }
    });
    right_box.append(&close_button);

    container.append(&right_box);

    // Set up state updates
    let app_label_clone = app_label.clone();
    let time_display_clone = time_display.clone();
    let warning_box_clone = warning_box.clone();
    let warning_label_clone = warning_label.clone();
    let battery_icon_clone = battery_icon.clone();
    let battery_label_clone = battery_label.clone();
    let volume_button_clone = volume_button.clone();

    glib::timeout_add_local(Duration::from_millis(500), move || {
        // Update session state
        let session_state = state.session_state();
        match &session_state {
            SessionState::NoSession => {
                app_label_clone.set_text("No session");
                time_display_clone.set_remaining(None);
                warning_box_clone.set_visible(false);
            }
            SessionState::Active {
                entry_name,
                started_at,
                time_limit_secs,
                paused,
                ..
            } => {
                app_label_clone.set_text(entry_name);
                // Calculate remaining time based on elapsed time since session start
                let remaining = time_limit_secs.map(|limit| {
                    let elapsed = started_at.elapsed().as_secs();
                    limit.saturating_sub(elapsed)
                });
                time_display_clone.set_remaining(remaining);
                time_display_clone.set_paused(*paused);
                warning_box_clone.set_visible(false);
            }
            SessionState::Warning {
                entry_name,
                warning_issued_at,
                time_remaining_at_warning,
                ..
            } => {
                app_label_clone.set_text(entry_name);
                // Calculate remaining time based on elapsed time since warning was issued
                let elapsed = warning_issued_at.elapsed().as_secs();
                let remaining = time_remaining_at_warning.saturating_sub(elapsed);
                time_display_clone.set_remaining(Some(remaining));
                warning_label_clone.set_text(&format!(
                    "Only {} seconds remaining!",
                    remaining
                ));
                warning_box_clone.set_visible(true);
            }
            SessionState::Ending { reason, .. } => {
                app_label_clone.set_text("Session ending...");
                warning_label_clone.set_text(reason);
                warning_box_clone.set_visible(true);
            }
        }

        // Update battery
        let battery = BatteryStatus::read();
        battery_icon_clone.set_icon_name(Some(battery.icon_name()));
        if let Some(percent) = battery.percent {
            battery_label_clone.set_text(&format!("{}%", percent));
        } else {
            battery_label_clone.set_text("--%");
        }

        // Update volume
        let volume = VolumeStatus::read();
        volume_button_clone.set_icon_name(volume.icon_name());

        glib::ControlFlow::Continue
    });

    container
}

fn load_css() {
    let css = r#"
        .hud-bar {
            background-color: rgba(30, 30, 30, 0.95);
            border: none;
            margin: 0;
            padding: 6px 12px;
        }

        .app-name {
            font-weight: bold;
            font-size: 14px;
            color: white;
        }

        .time-display {
            font-family: monospace;
            font-size: 14px;
            color: #88c0d0;
        }

        .time-display.time-warning {
            color: #ebcb8b;
        }

        .time-display.time-critical {
            color: #bf616a;
            animation: blink 1s infinite;
        }

        @keyframes blink {
            50% { opacity: 0.5; }
        }

        .warning-banner {
            background-color: rgba(235, 203, 139, 0.2);
            border-radius: 4px;
            padding: 4px 12px;
        }

        .warning-text {
            color: #ebcb8b;
            font-weight: bold;
        }

        .indicator-button,
        .control-button {
            min-width: 32px;
            min-height: 32px;
            padding: 4px;
            border-radius: 4px;
        }

        .indicator-button:hover,
        .control-button:hover {
            background-color: rgba(255, 255, 255, 0.1);
        }

        .close-button {
            min-width: 32px;
            min-height: 32px;
            padding: 4px;
            border-radius: 4px;
            color: #bf616a;
        }

        .close-button:hover {
            background-color: rgba(191, 97, 106, 0.3);
        }

        .battery-label {
            font-size: 12px;
            color: #a3be8c;
        }
    "#;

    let provider = gtk4::CssProvider::new();
    provider.load_from_data(css);

    gtk4::style_context_add_provider_for_display(
        &gtk4::gdk::Display::default().expect("Could not get display"),
        &provider,
        gtk4::STYLE_PROVIDER_PRIORITY_APPLICATION,
    );
}

fn run_event_loop(socket_path: PathBuf, state: SharedState) -> anyhow::Result<()> {
    let rt = Runtime::new()?;

    rt.block_on(async {
        loop {
            tracing::info!("Connecting to shepherdd at {:?}", socket_path);

            match IpcClient::connect(&socket_path).await {
                Ok(client) => {
                    tracing::info!("Connected to shepherdd");

                    let mut stream = match client.subscribe().await {
                        Ok(stream) => stream,
                        Err(e) => {
                            tracing::error!("Failed to subscribe: {}", e);
                            tokio::time::sleep(Duration::from_secs(1)).await;
                            continue;
                        }
                    };

                    loop {
                        match stream.next().await {
                            Ok(event) => {
                                tracing::debug!("Received event: {:?}", event);
                                state.handle_event(&event);
                            }
                            Err(e) => {
                                tracing::error!("Event stream error: {}", e);
                                break;
                            }
                        }
                    }
                }
                Err(e) => {
                    tracing::warn!("Failed to connect to shepherdd: {}", e);
                }
            }

            // Wait before reconnecting
            tokio::time::sleep(Duration::from_secs(2)).await;
        }
    })
}

fn start_metrics_updates(_state: SharedState) {
    // Battery and volume are now updated in the main UI loop
    // This function could be used for more expensive operations
    // that don't need to run as frequently
}