use crate::core::{CoreController, messages::{CoreCommand, UiEvent}};
use crate::network::PeerState;

use iced::widget::{
    container, column, row, text, button, text_input, scrollable, slider, checkbox, Column, Space,
};
use iced::{
    Color, Background, Border, Element, Subscription, Task, Theme, Event, keyboard,
};
use iroh::EndpointId;
use std::collections::HashMap;
use std::sync::{Arc, OnceLock};
use tokio::sync::Mutex;

static UI_RX: OnceLock<Mutex<Option<tokio::sync::mpsc::Receiver<UiEvent>>>> = OnceLock::new();

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Screen {
    Home,
    Room,
    Settings,
}

#[derive(Debug, Clone)]
pub enum AppMessage {
    NicknameChanged(String),
    TicketInputChanged(String),
    JoinPressed,
    CreatePressed,
    LeavePressed,
    ToggleMutePressed,
    ToggleDeafenPressed,
    UiEventReceived(UiEvent),
    CopyToClipboard,
    TogglePtt(bool),
    StartSettingHotkey,
    PeerVolumeChanged(EndpointId, f32),
    InputDeviceChanged(String),
    OutputDeviceChanged(String),
    EventOccurred(Event),
    NavigateToSettings,
    NavigateBack,
}

fn core_subscription() -> impl iced::futures::Stream<Item = UiEvent> {
    iced::stream::channel(100, |mut output: iced::futures::channel::mpsc::Sender<UiEvent>| async move {
        if let Some(rx_lock) = UI_RX.get() {
            let mut guard = rx_lock.lock().await;
            if let Some(mut rx) = guard.take() {
                use iced::futures::sink::SinkExt;
                while let Some(event) = rx.recv().await {
                    let _ = output.send(event).await;
                }
            }
        }
    })
}

pub struct AppState {
    name: String,
    ticket_input: String,
    status_message: String,
    self_id: String,
    ticket: String,
    is_muted: bool,
    is_deafened: bool,
    ptt_enabled: bool,
    ptt_active: bool,
    ptt_hotkey: keyboard::Key,
    is_setting_hotkey: bool,
    input_device: String,
    output_device: String,
    peers: HashMap<EndpointId, PeerState>,
    peer_volumes: HashMap<EndpointId, f32>,
    audio_levels: HashMap<EndpointId, f32>,
    controller: Arc<CoreController>,
    current_screen: Screen,
}

impl Default for AppState {
    fn default() -> Self {
        let (ui_tx, ui_rx) = tokio::sync::mpsc::channel(100);
        let controller = Arc::new(CoreController::new(ui_tx));
        let _ = UI_RX.set(Mutex::new(Some(ui_rx)));

        Self {
            name: "Peer".to_string(),
            ticket_input: "".to_string(),
            status_message: "Ready to connect".to_string(),
            self_id: "".to_string(),
            ticket: "".to_string(),
            is_muted: false,
            is_deafened: false,
            ptt_enabled: false,
            ptt_active: false,
            ptt_hotkey: keyboard::Key::Named(keyboard::key::Named::Space),
            is_setting_hotkey: false,
            input_device: "".to_string(),
            output_device: "".to_string(),
            peers: HashMap::new(),
            peer_volumes: HashMap::new(),
            audio_levels: HashMap::new(),
            controller,
            current_screen: Screen::Home,
        }
    }
}

fn theme(_state: &AppState) -> Theme {
    Theme::Dark
}

pub fn run_gui() -> iced::Result {
    iced::application(AppState::default, update, view)
        .title("PeerSpeak P2P Voice Chat")
        .theme(theme)
        .subscription(subscription)
        .window(iced::window::Settings {
            size: iced::Size::new(900.0, 600.0),
            position: iced::window::Position::Centered,
            exit_on_close_request: true,
            ..Default::default()
        })
        .run()
}

fn subscription(state: &AppState) -> Subscription<AppMessage> {
    let core_sub = Subscription::run(core_subscription).map(AppMessage::UiEventReceived);
    let event_sub = iced::event::listen().map(AppMessage::EventOccurred);
    Subscription::batch(vec![core_sub, event_sub])
}

fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
    match message {
        AppMessage::NicknameChanged(val) => {
            state.name = val;
        }
        AppMessage::TicketInputChanged(val) => {
            state.ticket_input = val;
        }
        AppMessage::JoinPressed => {
            state.status_message = "Connecting to room...".to_string();
            let _ = state.controller.send(CoreCommand::Join {
                name: state.name.clone(),
                ticket: state.ticket_input.clone(),
                input_device: if state.input_device.is_empty() { None } else { Some(state.input_device.clone()) },
                output_device: if state.output_device.is_empty() { None } else { Some(state.output_device.clone()) },
            });
        }
        AppMessage::CreatePressed => {
            state.status_message = "Creating room...".to_string();
            let _ = state.controller.send(CoreCommand::Join {
                name: state.name.clone(),
                ticket: "".to_string(),
                input_device: if state.input_device.is_empty() { None } else { Some(state.input_device.clone()) },
                output_device: if state.output_device.is_empty() { None } else { Some(state.output_device.clone()) },
            });
        }
        AppMessage::LeavePressed => {
            let _ = state.controller.send(CoreCommand::Leave);
        }
        AppMessage::ToggleMutePressed => {
            let _ = state.controller.send(CoreCommand::ToggleMute);
            state.is_muted = !state.is_muted;
        }
        AppMessage::ToggleDeafenPressed => {
            let _ = state.controller.send(CoreCommand::ToggleDeafen);
            state.is_deafened = !state.is_deafened;
        }
        AppMessage::UiEventReceived(event) => {
            match event {
                UiEvent::RoomJoined { ticket, self_id } => {
                    state.ticket = ticket;
                    state.self_id = self_id;
                    state.status_message = "Connected".to_string();
                    state.current_screen = Screen::Room;
                }
                UiEvent::RoomLeft => {
                    state.ticket = "".to_string();
                    state.peers.clear();
                    state.audio_levels.clear();
                    state.status_message = "Ready to connect".to_string();
                    state.current_screen = Screen::Home;
                }
                UiEvent::PeerJoined { id, state: peer_state } => {
                    state.peers.insert(id, peer_state);
                }
                UiEvent::PeerLeft { id } => {
                    state.peers.remove(&id);
                    state.audio_levels.remove(&id);
                }
                UiEvent::PeerUpdated { id, state: peer_state } => {
                    state.peers.insert(id, peer_state);
                }
                UiEvent::AudioLevels(levels) => {
                    for (id, val) in levels {
                        state.audio_levels.insert(id, val);
                    }
                }
                UiEvent::Error(err) => {
                    state.status_message = format!("Error: {}", err);
                }
            }
        }
        AppMessage::CopyToClipboard => {
            if !state.ticket.is_empty() {
                return iced::clipboard::write(state.ticket.clone());
            }
        }
        AppMessage::TogglePtt(enabled) => {
            state.ptt_enabled = enabled;
            let _ = state.controller.send(CoreCommand::SetPttMode(enabled));
        }
        AppMessage::StartSettingHotkey => {
            state.is_setting_hotkey = true;
        }
        AppMessage::PeerVolumeChanged(id, vol) => {
            state.peer_volumes.insert(id, vol);
            let _ = state.controller.send(CoreCommand::SetPeerVolume(id, vol));
        }
        AppMessage::InputDeviceChanged(val) => {
            state.input_device = val;
        }
        AppMessage::OutputDeviceChanged(val) => {
            state.output_device = val;
        }
        AppMessage::EventOccurred(Event::Keyboard(keyboard::Event::KeyPressed { key, .. })) => {
            if state.is_setting_hotkey {
                state.ptt_hotkey = key.clone();
                state.is_setting_hotkey = false;
            } else if state.ptt_enabled && key == state.ptt_hotkey && !state.ptt_active {
                state.ptt_active = true;
                let _ = state.controller.send(CoreCommand::SetPttActive(true));
            }
        }
        AppMessage::EventOccurred(Event::Keyboard(keyboard::Event::KeyReleased { key, .. })) => {
            if state.ptt_enabled && key == state.ptt_hotkey && state.ptt_active {
                state.ptt_active = false;
                let _ = state.controller.send(CoreCommand::SetPttActive(false));
            }
        }
        AppMessage::EventOccurred(_) => {}
        AppMessage::NavigateToSettings => {
            state.current_screen = Screen::Settings;
        }
        AppMessage::NavigateBack => {
            if state.ticket.is_empty() {
                state.current_screen = Screen::Home;
            } else {
                state.current_screen = Screen::Room;
            }
        }
    }
    Task::none()
}

fn horizontal_space() -> iced::widget::Space {
    iced::widget::Space::new().width(iced::Length::Fill)
}

fn vertical_space(height: f32) -> iced::widget::Space {
    iced::widget::Space::new().height(height)
}

fn view(state: &AppState) -> Element<'_, AppMessage> {
    // Theme Colors
    let color_crust = Color::from_rgb8(17, 17, 27);
    let color_mantle = Color::from_rgb8(24, 24, 37);
    let color_base = Color::from_rgb8(30, 30, 46);
    let color_surface = Color::from_rgb8(49, 50, 68);
    let color_text = Color::from_rgb8(205, 214, 244);
    let color_subtext = Color::from_rgb8(166, 173, 200);
    let color_blue = Color::from_rgb8(137, 180, 250);
    let color_lavender = Color::from_rgb8(180, 190, 254);
    let color_red = Color::from_rgb8(243, 139, 168);
    let color_maroon = Color::from_rgb8(233, 146, 160);
    let color_green = Color::from_rgb8(166, 227, 161);

    // Style Helpers
    let c_style = move |bg: Color, b_color: Color, radius: f32| {
        move |_theme: &Theme| container::Style {
            text_color: Some(color_text),
            background: Some(Background::Color(bg)),
            border: Border {
                color: b_color,
                width: if b_color == Color::TRANSPARENT { 0.0 } else { 1.0 },
                radius: radius.into(),
            },
            ..Default::default()
        }
    };

    let b_style = move |bg: Color, hover_bg: Color, text_c: Color, radius: f32| {
        move |_theme: &Theme, status: button::Status| {
            let active_bg = match status {
                button::Status::Hovered => hover_bg,
                _ => bg,
            };
            button::Style {
                background: Some(Background::Color(active_bg)),
                text_color: text_c,
                border: Border {
                    color: Color::TRANSPARENT,
                    width: 0.0,
                    radius: radius.into(),
                },
                ..Default::default()
            }
        }
    };

    let t_style = move |_theme: &Theme, _status: text_input::Status| {
        text_input::Style {
            background: Background::Color(color_crust),
            border: Border {
                color: color_surface,
                width: 1.0,
                radius: 6.0.into(),
            },
            icon: color_subtext,
            placeholder: Color::from_rgb8(108, 112, 134),
            value: color_text,
            selection: color_blue,
        }
    };

    let top_bar = row![
        horizontal_space(),
        button(text("⚙ Settings").size(14))
            .on_press(AppMessage::NavigateToSettings)
            .style(b_style(color_surface, color_blue, color_text, 6.0))
            .padding(8)
    ].width(iced::Length::Fill).padding(10);

    if state.current_screen == Screen::Settings {
        let content = column![
            text("Settings").size(32).color(color_text),
            vertical_space(20.0),
            text("Future settings and controls will be added here.").size(16).color(color_subtext),
            vertical_space(40.0),
            button(
                text("Back")
                    .size(16)
                    .align_x(iced::alignment::Horizontal::Center)
            )
            .on_press(AppMessage::NavigateBack)
            .style(b_style(color_surface, color_blue, color_text, 8.0))
            .padding(14)
            .width(iced::Length::Fixed(150.0))
        ]
        .align_x(iced::alignment::Horizontal::Center)
        .spacing(10);

        return container(content)
            .width(iced::Length::Fill)
            .height(iced::Length::Fill)
            .center_x(iced::Length::Fill)
            .center_y(iced::Length::Fill)
            .style(c_style(color_crust, Color::TRANSPARENT, 0.0))
            .into();
    }

    if state.current_screen == Screen::Home {
        // --- HOME SCREEN ---
        let logo = text("PEERSPEAK")
            .size(36)
            .color(color_blue);

        let subtitle = text("NAT-traversing full-mesh voice chat")
            .size(16)
            .color(color_subtext);

        let nickname_input = column![
            text("Nickname").size(14).color(color_subtext),
            vertical_space(4.0),
            text_input("Enter nickname...", &state.name)
                .on_input(AppMessage::NicknameChanged)
                .style(t_style)
                .padding(10)
        ];

        let create_btn = button(
            text("Create New Room")
                .size(16)
                .align_x(iced::alignment::Horizontal::Center)
        )
        .on_press(AppMessage::CreatePressed)
        .style(b_style(color_blue, color_lavender, color_crust, 8.0))
        .padding(12)
        .width(iced::Length::Fill);

        let join_group = column![
            text("Join Existing Room").size(14).color(color_subtext),
            vertical_space(4.0),
            text_input("Paste room ticket here...", &state.ticket_input)
                .on_input(AppMessage::TicketInputChanged)
                .style(t_style)
                .padding(10),
            vertical_space(8.0),
            button(
                text("Join Room")
                    .size(16)
                    .align_x(iced::alignment::Horizontal::Center)
            )
            .on_press(AppMessage::JoinPressed)
            .style(b_style(color_surface, color_blue, color_text, 8.0))
            .padding(12)
            .width(iced::Length::Fill)
        ];

        let status = text(&state.status_message)
            .size(14)
            .color(color_subtext);

        let content = container(
            column![
                logo,
                subtitle,
                vertical_space(20.0),
                nickname_input,
                vertical_space(16.0),
                create_btn,
                vertical_space(16.0),
                text("— OR —").size(12).color(color_surface).align_x(iced::alignment::Horizontal::Center),
                vertical_space(16.0),
                join_group,
                vertical_space(16.0),
                text("Device Settings (Optional Node Target IDs)").size(14).color(color_subtext),
                row![
                    text_input("Input Target", &state.input_device).on_input(AppMessage::InputDeviceChanged).style(t_style.clone()).padding(8),
                    horizontal_space(),
                    text_input("Output Target", &state.output_device).on_input(AppMessage::OutputDeviceChanged).style(t_style.clone()).padding(8),
                ].spacing(10),
                vertical_space(20.0),
                status
            ]
            .spacing(10)
            .align_x(iced::alignment::Horizontal::Center)
        )
        .style(c_style(color_mantle, color_surface, 12.0))
        .padding(30)
        .width(420);

        let scroll = scrollable(content);

        container(
            column![
                top_bar,
                vertical_space(20.0),
                scroll
            ].align_x(iced::alignment::Horizontal::Center)
        )
            .width(iced::Length::Fill)
            .height(iced::Length::Fill)
            .style(c_style(color_crust, Color::TRANSPARENT, 0.0))
            .into()
    } else {
        // --- ROOM SCREEN ---
        let header = row![
            text("PEERSPEAK")
                .size(20)
                .color(color_blue),
            horizontal_space(),
            text(format!("My ID: {}", &state.self_id[..8]))
                .size(14)
                .color(color_subtext),
            horizontal_space(),
            button(text("Copy Ticket").size(12))
                .on_press(AppMessage::CopyToClipboard)
                .style(b_style(color_surface, color_blue, color_text, 6.0))
                .padding(6)
        ]
        .align_y(iced::alignment::Vertical::Center);

        let header_container = container(header)
            .style(c_style(color_mantle, color_surface, 8.0))
            .padding(15)
            .width(iced::Length::Fill);

        // Peers Column
        let mut peers_list = Column::new().spacing(10);
        
        // Add ourselves
        let self_card = container(
            row![
                text(format!("{} (You)", &state.name)).size(16).color(color_text),
                horizontal_space(),
                if state.is_muted {
                    text("[Muted]").size(14).color(color_red)
                } else {
                    text("[Active]").size(14).color(color_green)
                }
            ]
            .align_y(iced::alignment::Vertical::Center)
        )
        .style(c_style(color_base, color_surface, 6.0))
        .padding(12);
        peers_list = peers_list.push(self_card);

        for (peer_id, peer) in &state.peers {
            let level = state.audio_levels.get(peer_id).copied().unwrap_or(0.0);
            let is_speaking = level > 0.01;

            let indicator = if peer.is_muted {
                text("[Muted]").size(14).color(color_red)
            } else if is_speaking {
                text("[Speaking]").size(14).color(color_green)
            } else {
                text("[Idle]").size(14).color(color_subtext)
            };

            let mut card_content = column![
                row![
                    column![
                        text(&peer.name).size(16).color(color_text),
                        text(format!("ID: {}", &peer_id.to_string()[..8])).size(11).color(color_subtext)
                    ],
                    horizontal_space(),
                    indicator
                ]
                .align_y(iced::alignment::Vertical::Center)
            ].spacing(8);

            // Peer volume slider
            let current_vol = state.peer_volumes.get(peer_id).copied().unwrap_or(1.0);
            let peer_id_clone = *peer_id;
            card_content = card_content.push(
                row![
                    text("Vol:").size(12).color(color_subtext),
                    slider(0.0..=2.0, current_vol, move |v| AppMessage::PeerVolumeChanged(peer_id_clone, v))
                ].spacing(8).align_y(iced::alignment::Vertical::Center)
            );

            let card = container(card_content)
            .style(c_style(
                if is_speaking { color_base } else { color_mantle },
                if is_speaking { color_green } else { color_surface },
                6.0
            ))
            .padding(12);

            peers_list = peers_list.push(card);
        }

        let scroll_peers = scrollable(peers_list);

        let peers_panel = container(
            column![
                text("Room Participants").size(18).color(color_blue),
                vertical_space(10.0),
                scroll_peers
            ]
        )
        .style(c_style(color_mantle, Color::TRANSPARENT, 0.0))
        .padding(15)
        .width(iced::Length::FillPortion(2))
        .height(iced::Length::Fill);

        // Control Panel Column
        let mute_text = if state.is_muted { "Unmute Mic" } else { "Mute Mic" };
        let mute_bg = if state.is_muted { color_red } else { color_surface };
        let mute_hover = if state.is_muted { color_maroon } else { color_blue };
        let mute_fg = if state.is_muted { color_crust } else { color_text };

        let deafen_text = if state.is_deafened { "Undeafen Audio" } else { "Deafen Audio" };
        let deafen_bg = if state.is_deafened { color_red } else { color_surface };
        let deafen_hover = if state.is_deafened { color_maroon } else { color_blue };
        let deafen_fg = if state.is_deafened { color_crust } else { color_text };

        let ctrl_buttons = column![
            button(
                text(mute_text)
                    .size(16)
                    .align_x(iced::alignment::Horizontal::Center)
            )
            .on_press(AppMessage::ToggleMutePressed)
            .style(b_style(mute_bg, mute_hover, mute_fg, 8.0))
            .padding(14)
            .width(iced::Length::Fill),
            vertical_space(10.0),
            button(
                text(deafen_text)
                    .size(16)
                    .align_x(iced::alignment::Horizontal::Center)
            )
            .on_press(AppMessage::ToggleDeafenPressed)
            .style(b_style(deafen_bg, deafen_hover, deafen_fg, 8.0))
            .padding(14)
            .width(iced::Length::Fill),
            vertical_space(20.0),
            checkbox(state.ptt_enabled).label("Push-to-Talk").on_toggle(AppMessage::TogglePtt),
            vertical_space(10.0),
            if state.ptt_enabled {
                column![
                    text(format!("Hotkey: {}", if state.is_setting_hotkey { "Press any key...".to_string() } else { format!("{:?}", state.ptt_hotkey) })).size(14).color(color_subtext),
                    button(text("Set Hotkey").size(12).align_x(iced::alignment::Horizontal::Center))
                        .on_press(AppMessage::StartSettingHotkey)
                        .style(b_style(color_surface, color_blue, color_text, 6.0))
                        .padding(8)
                        .width(iced::Length::Fill)
                ].spacing(8)
            } else {
                column![]
            },
            vertical_space(30.0),
            button(
                text("Leave Room")
                    .size(16)
                    .align_x(iced::alignment::Horizontal::Center)
            )
            .on_press(AppMessage::LeavePressed)
            .style(b_style(color_red, color_maroon, color_crust, 8.0))
            .padding(14)
            .width(iced::Length::Fill)
        ];

        let control_panel = container(
            column![
                text("Controls").size(18).color(color_blue),
                vertical_space(15.0),
                ctrl_buttons,
                vertical_space(20.0),
                text(&state.status_message).size(12).color(color_subtext)
            ]
        )
        .style(c_style(color_mantle, Color::TRANSPARENT, 0.0))
        .padding(15)
        .width(iced::Length::FillPortion(1))
        .height(iced::Length::Fill);

        let main_layout = row![peers_panel, control_panel].spacing(15);

        container(
            column![
                top_bar,
                header_container,
                vertical_space(15.0),
                main_layout
            ]
        )
        .padding(15)
        .width(iced::Length::Fill)
        .height(iced::Length::Fill)
        .style(c_style(color_crust, Color::TRANSPARENT, 0.0))
        .into()
    }
}