// ============================================================================
// app.rs -- Application State & eframe::App Implementation
// ============================================================================
// Central state struct shared across all UI modules.
// Tab switching pauses inactive tab computation.
// ============================================================================

use crate::gmp_engine::{IntervalProfile, RawTick};
use crate::zmq_bridge::{OrderRequest, OrderResponse, PositionData, PendingOrderData, TickData};
use crate::tab_time;
use crate::tab_trade;
use crate::trading_panel;
use std::io::Write;
use std::path::PathBuf;
use tokio::sync::mpsc;

// ─── Tab Enum ────────────────────────────────────────────────────────────────

#[derive(Clone, Copy, PartialEq, Eq)]
pub enum TabMode {
    TimeBased,
    TradeBased,
}

// ─── Application State ──────────────────────────────────────────────────────

pub struct AppState {
    // ZMQ channels
    pub tick_rx:     mpsc::Receiver<TickData>,
    pub order_tx:    mpsc::Sender<OrderRequest>,
    pub response_rx: mpsc::Receiver<OrderResponse>,

    // Raw tick buffer (rolling)
    pub raw_ticks: Vec<RawTick>,
    pub symbol:    String,

    // Account
    pub balance:     f64,
    pub equity:      f64,
    pub margin:      f64,
    pub free_margin: f64,
    pub min_lot:     f64,
    pub max_lot:     f64,
    pub lot_step:    f64,

    // Positions & orders (from latest tick)
    pub positions:      Vec<PositionData>,
    pub pending_orders: Vec<PendingOrderData>,

    // Trading UI
    pub lot_size:         f64,
    pub lot_size_str:     String,
    pub limit_price_str:  String,
    pub last_status:      Option<String>,

    // Chart config
    pub bin_size:     f64,
    pub bin_size_str: String,
    pub active_tab:   TabMode,

    // Time-based tab
    pub time_interval_secs: u64,
    pub time_input_str:     String,
    pub time_parse_err:     Option<String>,
    pub time_profiles:      Vec<IntervalProfile>,
    pub profiles_dirty:     bool,
    pub show_footprint:     bool,

    // Trade-based tab
    pub trade_interval:       usize,
    pub trade_input_str:      String,
    pub trade_profiles:       Vec<IntervalProfile>,
    pub profiles_dirty_trade: bool,
    pub show_footprint_trade: bool,

    // History download
    pub history_start: String,
    pub history_end:   String,
    pub history_tf:    String,
    pub history_mode:  String,

    // Live recording
    pub is_recording:    bool,
    pub live_record_file: Option<std::fs::File>,

    // Output
    pub output_dir:      PathBuf,
    pub request_counter: u64,
    pub pending_history: Option<(u64, String, String, String)>,

    // Max ticks to keep in memory
    max_ticks: usize,
}

impl AppState {
    pub fn new(
        tick_rx: mpsc::Receiver<TickData>,
        order_tx: mpsc::Sender<OrderRequest>,
        response_rx: mpsc::Receiver<OrderResponse>,
    ) -> Self {
        let now = chrono::Local::now();
        let today = now.format("%Y.%m.%d").to_string();
        let output_dir = PathBuf::from("output");
        std::fs::create_dir_all(&output_dir).ok();

        Self {
            tick_rx,
            order_tx,
            response_rx,
            raw_ticks: Vec::new(),
            symbol: "Waiting...".to_string(),
            balance: 0.0,
            equity: 0.0,
            margin: 0.0,
            free_margin: 0.0,
            min_lot: 0.01,
            max_lot: 100.0,
            lot_step: 0.01,
            positions: Vec::new(),
            pending_orders: Vec::new(),
            lot_size: 0.01,
            lot_size_str: "0.01".to_string(),
            limit_price_str: "0.0".to_string(),
            last_status: None,
            bin_size: 1.0,
            bin_size_str: "1".to_string(),
            active_tab: TabMode::TimeBased,
            time_interval_secs: 60,
            time_input_str: "1m".to_string(),
            time_parse_err: None,
            time_profiles: Vec::new(),
            profiles_dirty: true,
            show_footprint: false,
            trade_interval: 50,
            trade_input_str: "50".to_string(),
            trade_profiles: Vec::new(),
            profiles_dirty_trade: true,
            show_footprint_trade: false,
            history_start: today.clone(),
            history_end: today,
            history_tf: "M1".to_string(),
            history_mode: "TICKS".to_string(),
            is_recording: false,
            live_record_file: None,
            output_dir,
            request_counter: 0,
            pending_history: None,
            max_ticks: 50_000,
        }
    }
}

// ─── eframe::App ─────────────────────────────────────────────────────────────

pub struct GmpTerminalApp {
    pub state: AppState,
}

impl GmpTerminalApp {
    pub fn new(
        tick_rx: mpsc::Receiver<TickData>,
        order_tx: mpsc::Sender<OrderRequest>,
        response_rx: mpsc::Receiver<OrderResponse>,
    ) -> Self {
        Self {
            state: AppState::new(tick_rx, order_tx, response_rx),
        }
    }
}

impl eframe::App for GmpTerminalApp {
    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
        let state = &mut self.state;

        // ── Drain tick channel ──
        let mut new_ticks = false;
        while let Ok(tick) = state.tick_rx.try_recv() {
            state.symbol = tick.symbol.clone();

            // Record if active
            if state.is_recording {
                if let Some(ref mut file) = state.live_record_file {
                    let _ = writeln!(
                        file, "{},{},{},{}",
                        tick.time, tick.bid, tick.ask, tick.volume
                    );
                }
            }

            // Update account info
            if tick.balance > 0.0 {
                state.balance = tick.balance;
                state.equity = tick.equity;
                state.margin = tick.margin;
                state.free_margin = tick.free_margin;
                state.min_lot = tick.min_lot;
                state.max_lot = tick.max_lot;
                if tick.lot_step > 0.0 {
                    state.lot_step = tick.lot_step;
                }
            }

            // Update positions/orders
            state.positions = tick.positions.clone();
            state.pending_orders = tick.orders.clone();

            // Use mid-price (avg of bid/ask) for GMP computation
            let mid = (tick.bid + tick.ask) * 0.5;
            let idx = state.raw_ticks.len();
            state.raw_ticks.push(RawTick {
                price: mid,
                time: tick.time,
                index: idx,
            });

            new_ticks = true;
        }

        // Trim buffer
        if state.raw_ticks.len() > state.max_ticks {
            let excess = state.raw_ticks.len() - state.max_ticks;
            state.raw_ticks.drain(..excess);
        }

        // Mark profiles dirty if new ticks arrived
        if new_ticks {
            match state.active_tab {
                TabMode::TimeBased  => state.profiles_dirty = true,
                TabMode::TradeBased => state.profiles_dirty_trade = true,
            }
        }

        // ── Drain order responses ──
        while let Ok(resp) = state.response_rx.try_recv() {
            if resp.success {
                if let Some(ref msg) = resp.message {
                    if msg.contains("||CSV_DATA||") {
                        handle_csv_response(state, msg);
                    } else {
                        state.last_status = Some(format!("OK: {}", msg));
                    }
                } else {
                    state.last_status = Some(format!(
                        "OK: ticket {}",
                        resp.ticket.unwrap_or(0)
                    ));
                }
            } else {
                state.pending_history = None;
                state.last_status = Some(format!(
                    "FAIL: {}",
                    resp.error.unwrap_or_else(|| "Unknown".to_string())
                ));
            }
        }

        // ── Side Panel ──
        egui::SidePanel::left("trading_panel")
            .min_width(260.0)
            .max_width(300.0)
            .show(ctx, |ui| {
                egui::ScrollArea::vertical().show(ui, |ui| {
                    trading_panel::render_trading_panel(ui, state);
                });
            });

        // ── Central Panel ──
        egui::CentralPanel::default().show(ctx, |ui| {
            // Header
            ui.horizontal(|ui| {
                ui.heading(&state.symbol);
                if let Some(last) = state.raw_ticks.last() {
                    let price = last.price;
                    ui.label(format!("{:.5}", price));
                }
            });

            // Tab bar
            ui.horizontal(|ui| {
                if ui
                    .selectable_label(state.active_tab == TabMode::TimeBased, "Time-Based")
                    .clicked()
                {
                    state.active_tab = TabMode::TimeBased;
                    state.profiles_dirty = true;
                }
                if ui
                    .selectable_label(state.active_tab == TabMode::TradeBased, "Trade-Based")
                    .clicked()
                {
                    state.active_tab = TabMode::TradeBased;
                    state.profiles_dirty_trade = true;
                }
            });

            ui.separator();

            // Active tab content -- only the selected tab computes
            match state.active_tab {
                TabMode::TimeBased  => tab_time::render(ui, state),
                TabMode::TradeBased => tab_trade::render(ui, state),
            }
        });

        // Continuous repaint
        ctx.request_repaint();
    }
}

// ─── CSV Response Handler ────────────────────────────────────────────────────

fn handle_csv_response(state: &mut AppState, msg: &str) {
    let parts: Vec<&str> = msg.splitn(2, "||CSV_DATA||").collect();
    if parts.len() == 2 {
        let info = parts[0];
        let csv = parts[1];

        if let Some((id, sym, tf, mode)) = state.pending_history.take() {
            let ts = chrono::Local::now().format("%Y%m%d_%H%M%S");
            let filename = format!(
                "{}/History_{}_{}_{}_ID{:04}_{}.csv",
                state.output_dir.display(),
                sym, tf, mode, id, ts
            );
            let csv_clean = csv.replace("|NL|", "\n");
            match std::fs::write(&filename, csv_clean) {
                Ok(_) => {
                    state.last_status = Some(format!("Saved: {} ({})", filename, info));
                }
                Err(e) => {
                    state.last_status = Some(format!("Save error: {}", e));
                }
            }
        } else {
            state.last_status = Some(format!("OK: {}", info));
        }
    } else {
        state.last_status = Some(format!("OK: {}", msg));
    }
}