from __future__ import annotations

import asyncio
from datetime import datetime
from typing import TYPE_CHECKING

from textual.app import ComposeResult
from textual.binding import Binding
from textual.containers import Horizontal, Vertical
from textual.screen import Screen
from textual.widgets import Button, DataTable, Footer, Header, Input, RichLog, Static

from db.database import SessionLocal
from schemas import SendMessageRequest
from services import conversation_service, message_service

if TYPE_CHECKING:
    from db.models import Message

# Kanal-Symbole und Farben
CHANNEL_ICON = {"telegram": "✈", "whatsapp": "📱", "sms": "✉"}
CHANNEL_COLOR = {"telegram": "cyan", "whatsapp": "green", "sms": "yellow"}


class MainScreen(Screen):
    BINDINGS = [
        Binding("n", "new_message", "Neu"),
        Binding("r", "refresh", "Aktualisieren"),
        Binding("q", "quit_app", "Beenden"),
    ]

    def __init__(self) -> None:
        super().__init__()
        self._current_conv_id: str | None = None
        self._conv_id_map: dict[int, str] = {}  # Zeilen-Index → conv_id

    # ── Layout ─────────────────────────────────────────────────────────────────

    def compose(self) -> ComposeResult:
        yield Header(show_clock=True)
        with Horizontal(id="main-container"):
            # Seitenleiste
            with Vertical(id="sidebar"):
                yield Static("Konversationen", id="sidebar-title")
                yield DataTable(id="conv-table", cursor_type="row", show_header=True)
            # Chat
            with Vertical(id="chat-area"):
                yield Static("Kein Chat geöffnet", id="chat-header")
                yield RichLog(id="message-log", highlight=True, markup=True, wrap=True)
                with Horizontal(id="input-bar"):
                    yield Input(
                        placeholder="Nachricht eingeben… (Enter = Senden)",
                        id="msg-input",
                    )
                    yield Button("Senden", variant="primary", id="send-btn")
        yield Footer()

    def on_mount(self) -> None:
        self._setup_table()
        self._load_conversations()
        # Neuer-Nachrichten-Callback registrieren
        message_service.add_new_message_callback(self._on_new_message)

    # ── Konversationsliste ─────────────────────────────────────────────────────

    def _setup_table(self) -> None:
        table = self.query_one("#conv-table", DataTable)
        table.add_column("K", width=2)
        table.add_column("Name", width=16)
        table.add_column("Letzte Nachricht", width=22)
        table.add_column("🔔", width=3)

    def _load_conversations(self) -> None:
        db = SessionLocal()
        try:
            convs = conversation_service.get_all(db)
            table = self.query_one("#conv-table", DataTable)
            table.clear()
            self._conv_id_map.clear()
            for idx, conv in enumerate(convs):
                last = conv.messages[-1] if conv.messages else None
                last_text = (last.text[:20] + "…") if last and len(last.text) > 20 else (last.text if last else "")
                icon = CHANNEL_ICON.get(conv.channel, "?")
                unread = conversation_service.unread_count(db, conv.id)
                badge = str(unread) if unread else ""
                table.add_row(icon, conv.title or conv.id[:8], last_text, badge)
                self._conv_id_map[idx] = conv.id
        finally:
            db.close()

    # ── Nachrichten ────────────────────────────────────────────────────────────

    def _load_messages(self, conv_id: str) -> None:
        db = SessionLocal()
        try:
            conv = conversation_service.get_by_id(db, conv_id)
            if not conv:
                return
            icon = CHANNEL_ICON.get(conv.channel, "?")
            color = CHANNEL_COLOR.get(conv.channel, "white")
            header = self.query_one("#chat-header", Static)
            header.update(f"{icon} [{color}]{conv.title or conv.id[:8]}[/{color}]  [{conv.channel}]")

            log = self.query_one("#message-log", RichLog)
            log.clear()
            msgs = conversation_service.get_messages(db, conv_id, limit=100)
            conversation_service.mark_all_read(db, conv_id)
            for msg in msgs:
                self._render_message(log, msg, color)
        finally:
            db.close()

    def _render_message(self, log: RichLog, msg: "Message", channel_color: str) -> None:
        ts = msg.created_at.strftime("%H:%M") if msg.created_at else "??"
        direction_prefix = "▶ " if msg.direction == "outbound" else "◀ "
        status_suffix = " ✗" if msg.status == "failed" else ""
        style = "dim" if msg.direction == "outbound" else ""
        log.write(
            f"[dim]{ts}[/dim] [{style}]{direction_prefix}{msg.text}{status_suffix}[/{style}]"
        )

    # ── Events ─────────────────────────────────────────────────────────────────

    def on_data_table_row_selected(self, event: DataTable.RowSelected) -> None:
        row_idx = event.cursor_row
        conv_id = self._conv_id_map.get(row_idx)
        if conv_id:
            self._current_conv_id = conv_id
            self._load_messages(conv_id)
            # Ungelesen-Badge in Tabelle zurücksetzen
            table = self.query_one("#conv-table", DataTable)
            table.update_cell_at((row_idx, 3), "")
            self.query_one("#msg-input", Input).focus()

    def on_input_submitted(self, event: Input.Submitted) -> None:
        if event.input.id == "msg-input":
            self._send_current()

    def on_button_pressed(self, event: Button.Pressed) -> None:
        if event.button.id == "send-btn":
            self._send_current()

    def _send_current(self) -> None:
        inp = self.query_one("#msg-input", Input)
        text = inp.value.strip()
        if not text or not self._current_conv_id:
            return
        inp.clear()
        asyncio.create_task(self._send_async(text))

    async def _send_async(self, text: str) -> None:
        db = SessionLocal()
        try:
            conv = conversation_service.get_by_id(db, self._current_conv_id)
            if not conv:
                return
            req = SendMessageRequest(
                channel=conv.channel,
                recipient_phone=conv.channel_conversation_id if conv.channel != "telegram" else None,
                recipient_telegram_id=conv.channel_conversation_id if conv.channel == "telegram" else None,
                text=text,
            )
            await message_service.send(db, req)
            self._load_messages(self._current_conv_id)
            self._load_conversations()
        finally:
            db.close()

    async def _on_new_message(self, msg: "Message") -> None:
        """Callback: neue eingehende Nachricht → TUI aktualisieren."""
        self.call_from_thread(self._refresh_on_new_message, msg.conversation_id)

    def _refresh_on_new_message(self, conv_id: str) -> None:
        self._load_conversations()
        if self._current_conv_id == conv_id:
            self._load_messages(conv_id)

    # ── Actions ────────────────────────────────────────────────────────────────

    def action_new_message(self) -> None:
        from tui.screens.compose_screen import ComposeScreen

        self.app.push_screen(ComposeScreen(), self._compose_callback)

    def _compose_callback(self, result: dict | None) -> None:
        if not result:
            return
        asyncio.create_task(self._send_compose(result))

    async def _send_compose(self, result: dict) -> None:
        db = SessionLocal()
        try:
            channel = result["channel"]
            recipient = result["recipient"]
            req = SendMessageRequest(
                channel=channel,
                recipient_phone=recipient if channel != "telegram" else None,
                recipient_telegram_id=recipient if channel == "telegram" else None,
                text=result["text"],
            )
            await message_service.send(db, req)
            self._load_conversations()
        finally:
            db.close()

    def action_refresh(self) -> None:
        self._load_conversations()
        if self._current_conv_id:
            self._load_messages(self._current_conv_id)

    def action_quit_app(self) -> None:
        self.app.exit()