"""Discord bot adapter — slash commands and event handlers."""

import asyncio
import logging
import os
import signal
import discord
from discord import app_commands

from src.config import Config
from src.claude_session import (
    clear_session,
    get_active_session,
    set_session_model,
    PROJECT_ROOT,
    VALID_MODELS,
)
from src.router import route_message

logger = logging.getLogger("echo-core.discord")

# Module-level config reference, set by create_bot()
_config: Config | None = None


def _get_config() -> Config:
    """Return the module-level config, raising if not initialized."""
    if _config is None:
        raise RuntimeError("Bot not initialized — call create_bot() first")
    return _config


# --- Authorization helpers ---


def is_owner(user_id: str) -> bool:
    """Check if user_id matches config bot.owner."""
    return _get_config().get("bot.owner") == user_id


def is_admin(user_id: str) -> bool:
    """Check if user_id is owner or in admins list."""
    if is_owner(user_id):
        return True
    admins = _get_config().get("bot.admins", [])
    return user_id in admins


def is_registered_channel(channel_id: str) -> bool:
    """Check if channel_id is in any registered channel entry."""
    channels = _get_config().get("channels", {})
    return any(ch.get("id") == channel_id for ch in channels.values())


def _channel_alias_for_id(channel_id: str) -> str | None:
    """Resolve a Discord channel ID to its config alias."""
    channels = _get_config().get("channels", {})
    for alias, info in channels.items():
        if info.get("id") == channel_id:
            return alias
    return None


# --- Message splitting helper ---


def split_message(text: str, limit: int = 2000) -> list[str]:
    """Split text into chunks that fit Discord's message limit."""
    if len(text) <= limit:
        return [text]

    chunks = []
    while text:
        if len(text) <= limit:
            chunks.append(text)
            break
        # Find last newline before limit
        split_at = text.rfind('\n', 0, limit)
        if split_at == -1:
            split_at = limit
        chunks.append(text[:split_at])
        text = text[split_at:].lstrip('\n')
    return chunks


# --- Factory ---


def create_bot(config: Config) -> discord.Client:
    """Create and configure the Discord bot with all slash commands."""
    global _config
    _config = config

    intents = discord.Intents.default()
    intents.message_content = True

    client = discord.Client(intents=intents)
    tree = app_commands.CommandTree(client)
    client.tree = tree  # type: ignore[attr-defined]

    # --- Slash commands ---

    @tree.command(name="ping", description="Check bot latency")
    async def ping(interaction: discord.Interaction) -> None:
        latency_ms = round(client.latency * 1000)
        await interaction.response.send_message(
            f"Pong! Latency: {latency_ms}ms", ephemeral=True
        )

    @tree.command(name="help", description="List available commands")
    async def help_cmd(interaction: discord.Interaction) -> None:
        lines = [
            "**Echo Commands**",
            "`/ping` — Check bot latency",
            "`/help` — Show this help message",
            "`/setup` — Claim ownership of the bot (first run only)",
            "`/channel add <alias>` — Register current channel (owner only)",
            "`/channels` — List registered channels",
            "`/admin add <user_id>` — Add an admin (owner only)",
            "`/clear` — Clear the session for this channel",
            "`/status` — Show session status for this channel",
            "`/model` — View current model and available models",
            "`/model <choice>` — Change model for this channel's session",
            "`/logs [n]` — Show last N log lines (default 10)",
            "`/restart` — Restart the bot process (owner only)",
            "`/heartbeat` — Run heartbeat health checks",
            "",
            "**Cron Jobs**",
            "`/cron list` — List all scheduled jobs",
            "`/cron run <name>` — Force-run a job now",
            "`/cron add <name> <expr> [model]` — Create a scheduled job (admin)",
            "`/cron remove <name>` — Remove a job (admin)",
            "`/cron enable <name>` — Enable a job (admin)",
            "`/cron disable <name>` — Disable a job (admin)",
        ]
        await interaction.response.send_message(
            "\n".join(lines), ephemeral=True
        )

    @tree.command(name="setup", description="Claim ownership of the bot")
    async def setup(interaction: discord.Interaction) -> None:
        if config.get("bot.owner") is not None:
            await interaction.response.send_message(
                "Owner already set.", ephemeral=True
            )
            return
        config.set("bot.owner", str(interaction.user.id))
        config.save()
        await interaction.response.send_message(
            "You are now the owner of Echo.", ephemeral=True
        )

    channel_group = app_commands.Group(
        name="channel", description="Channel management"
    )

    @channel_group.command(name="add", description="Register current channel")
    @app_commands.describe(alias="Short name for this channel")
    async def channel_add(
        interaction: discord.Interaction, alias: str
    ) -> None:
        if not is_owner(str(interaction.user.id)):
            await interaction.response.send_message(
                "Owner only.", ephemeral=True
            )
            return
        config.set(
            f"channels.{alias}",
            {"id": str(interaction.channel_id), "default_model": "sonnet"},
        )
        config.save()
        await interaction.response.send_message(
            f"Channel registered as '{alias}'.", ephemeral=True
        )

    tree.add_command(channel_group)

    admin_group = app_commands.Group(
        name="admin", description="Admin management"
    )

    @admin_group.command(name="add", description="Add an admin user")
    @app_commands.describe(user_id="Discord user ID to add as admin")
    async def admin_add(
        interaction: discord.Interaction, user_id: str
    ) -> None:
        if not is_owner(str(interaction.user.id)):
            await interaction.response.send_message(
                "Owner only.", ephemeral=True
            )
            return
        admins = config.get("bot.admins", [])
        if user_id not in admins:
            admins.append(user_id)
            config.set("bot.admins", admins)
            config.save()
        await interaction.response.send_message(
            f"User {user_id} added as admin.", ephemeral=True
        )

    tree.add_command(admin_group)

    # --- Cron commands ---

    cron_group = app_commands.Group(
        name="cron", description="Manage scheduled jobs"
    )

    @cron_group.command(name="list", description="List all scheduled jobs")
    async def cron_list(interaction: discord.Interaction) -> None:
        scheduler = getattr(client, "scheduler", None)
        if scheduler is None:
            await interaction.response.send_message(
                "Scheduler not available.", ephemeral=True
            )
            return
        jobs = scheduler.list_jobs()
        if not jobs:
            await interaction.response.send_message(
                "No scheduled jobs.", ephemeral=True
            )
            return
        lines = [
            f"{'Name':<24} {'Cron':<14} {'Channel':<10} {'Model':<8} {'On':<5} {'Status':<8} {'Next Run'}"
        ]
        for j in jobs:
            enabled = "yes" if j.get("enabled") else "no"
            last_status = j.get("last_status") or "\u2014"
            next_run = j.get("next_run") or "\u2014"
            if next_run != "\u2014" and len(next_run) > 19:
                next_run = next_run[:19]
            lines.append(
                f"{j['name']:<24} {j['cron']:<14} {j['channel']:<10} {j['model']:<8} {enabled:<5} {last_status:<8} {next_run}"
            )
        table = "```\n" + "\n".join(lines) + "\n```"
        await interaction.response.send_message(table, ephemeral=True)

    @cron_group.command(name="run", description="Force-run a scheduled job")
    @app_commands.describe(name="Job name to run")
    async def cron_run(interaction: discord.Interaction, name: str) -> None:
        scheduler = getattr(client, "scheduler", None)
        if scheduler is None:
            await interaction.response.send_message(
                "Scheduler not available.", ephemeral=True
            )
            return
        await interaction.response.defer()
        try:
            result = await scheduler.run_job(name)
            truncated = result[:1900] if len(result) > 1900 else result
            await interaction.followup.send(truncated)
        except KeyError:
            await interaction.followup.send(f"Job '{name}' not found.")
        except Exception as e:
            await interaction.followup.send(f"Error running job: {e}")

    @cron_group.command(name="add", description="Create a new scheduled job")
    @app_commands.describe(
        name="Job name (lowercase, hyphens allowed)",
        expression="Cron expression (e.g. '30 6 * * *')",
        model="AI model to use (default: sonnet)",
    )
    @app_commands.choices(model=[
        app_commands.Choice(name="opus", value="opus"),
        app_commands.Choice(name="sonnet", value="sonnet"),
        app_commands.Choice(name="haiku", value="haiku"),
    ])
    async def cron_add(
        interaction: discord.Interaction,
        name: str,
        expression: str,
        model: app_commands.Choice[str] | None = None,
    ) -> None:
        if not is_admin(str(interaction.user.id)):
            await interaction.response.send_message(
                "Admin only.", ephemeral=True
            )
            return
        scheduler = getattr(client, "scheduler", None)
        if scheduler is None:
            await interaction.response.send_message(
                "Scheduler not available.", ephemeral=True
            )
            return
        channel_alias = _channel_alias_for_id(str(interaction.channel_id))
        if channel_alias is None:
            await interaction.response.send_message(
                "This channel is not registered. Use `/channel add` first.",
                ephemeral=True,
            )
            return
        model_value = model.value if model else "sonnet"
        await interaction.response.send_message(
            f"Creating job **{name}** (`{expression}`, model: {model_value}, channel: {channel_alias}).\n"
            "Send your prompt text as the next message in this channel.",
        )

        def check(m: discord.Message) -> bool:
            return (
                m.author == interaction.user
                and m.channel.id == interaction.channel_id
            )

        try:
            prompt_msg = await client.wait_for(
                "message", check=check, timeout=120
            )
        except asyncio.TimeoutError:
            await interaction.followup.send("Timed out waiting for prompt.")
            return

        try:
            job = scheduler.add_job(
                name=name,
                cron=expression,
                channel=channel_alias,
                prompt=prompt_msg.content,
                model=model_value,
            )
            next_run = job.get("next_run") or "\u2014"
            await interaction.channel.send(
                f"Job **{name}** created.\n"
                f"Cron: `{expression}` | Channel: {channel_alias} | Model: {model_value}\n"
                f"Next run: {next_run}"
            )
        except ValueError as e:
            await interaction.channel.send(f"Error creating job: {e}")

    @cron_group.command(name="remove", description="Remove a scheduled job")
    @app_commands.describe(name="Job name to remove")
    async def cron_remove(interaction: discord.Interaction, name: str) -> None:
        if not is_admin(str(interaction.user.id)):
            await interaction.response.send_message(
                "Admin only.", ephemeral=True
            )
            return
        scheduler = getattr(client, "scheduler", None)
        if scheduler is None:
            await interaction.response.send_message(
                "Scheduler not available.", ephemeral=True
            )
            return
        if scheduler.remove_job(name):
            await interaction.response.send_message(
                f"Job '{name}' removed.", ephemeral=True
            )
        else:
            await interaction.response.send_message(
                f"Job '{name}' not found.", ephemeral=True
            )

    @cron_group.command(name="enable", description="Enable a scheduled job")
    @app_commands.describe(name="Job name to enable")
    async def cron_enable(
        interaction: discord.Interaction, name: str
    ) -> None:
        if not is_admin(str(interaction.user.id)):
            await interaction.response.send_message(
                "Admin only.", ephemeral=True
            )
            return
        scheduler = getattr(client, "scheduler", None)
        if scheduler is None:
            await interaction.response.send_message(
                "Scheduler not available.", ephemeral=True
            )
            return
        if scheduler.enable_job(name):
            await interaction.response.send_message(
                f"Job '{name}' enabled.", ephemeral=True
            )
        else:
            await interaction.response.send_message(
                f"Job '{name}' not found.", ephemeral=True
            )

    @cron_group.command(name="disable", description="Disable a scheduled job")
    @app_commands.describe(name="Job name to disable")
    async def cron_disable(
        interaction: discord.Interaction, name: str
    ) -> None:
        if not is_admin(str(interaction.user.id)):
            await interaction.response.send_message(
                "Admin only.", ephemeral=True
            )
            return
        scheduler = getattr(client, "scheduler", None)
        if scheduler is None:
            await interaction.response.send_message(
                "Scheduler not available.", ephemeral=True
            )
            return
        if scheduler.disable_job(name):
            await interaction.response.send_message(
                f"Job '{name}' disabled.", ephemeral=True
            )
        else:
            await interaction.response.send_message(
                f"Job '{name}' not found.", ephemeral=True
            )

    tree.add_command(cron_group)

    @tree.command(name="heartbeat", description="Run heartbeat health checks")
    async def heartbeat_cmd(interaction: discord.Interaction) -> None:
        from src.heartbeat import run_heartbeat
        await interaction.response.defer(ephemeral=True)
        try:
            result = await asyncio.to_thread(run_heartbeat)
            await interaction.followup.send(result, ephemeral=True)
        except Exception as e:
            await interaction.followup.send(
                f"Heartbeat error: {e}", ephemeral=True
            )

    @tree.command(name="channels", description="List registered channels")
    async def channels(interaction: discord.Interaction) -> None:
        ch_map = config.get("channels", {})
        if not ch_map:
            await interaction.response.send_message(
                "No channels registered yet.", ephemeral=True
            )
            return
        lines = []
        for alias, info in ch_map.items():
            cid = info.get("id", "?")
            model = info.get("default_model", "?")
            lines.append(f"\u2022 {alias} \u2192 <#{cid}> (model: {model})")
        await interaction.response.send_message(
            "\n".join(lines), ephemeral=True
        )

    @tree.command(name="clear", description="Clear the session for this channel")
    async def clear(interaction: discord.Interaction) -> None:
        channel_id = str(interaction.channel_id)
        default_model = config.get("bot.default_model", "sonnet")
        removed = clear_session(channel_id)
        if removed:
            await interaction.response.send_message(
                f"Session cleared. Model reset to {default_model}.",
                ephemeral=True,
            )
        else:
            await interaction.response.send_message(
                "No active session for this channel.", ephemeral=True
            )

    @tree.command(name="status", description="Show session status")
    async def status(interaction: discord.Interaction) -> None:
        channel_id = str(interaction.channel_id)
        session = get_active_session(channel_id)
        if session is None:
            await interaction.response.send_message(
                "No active session.", ephemeral=True
            )
            return
        sid = session.get("session_id", "?")
        truncated_sid = sid[:8] + "..." if len(sid) > 8 else sid
        model = session.get("model", "?")
        count = session.get("message_count", 0)
        await interaction.response.send_message(
            f"**Model:** {model}\n"
            f"**Session:** `{truncated_sid}`\n"
            f"**Messages:** {count}",
            ephemeral=True,
        )

    @tree.command(name="model", description="View or change the AI model")
    @app_commands.describe(choice="Model to switch to")
    @app_commands.choices(choice=[
        app_commands.Choice(name="opus", value="opus"),
        app_commands.Choice(name="sonnet", value="sonnet"),
        app_commands.Choice(name="haiku", value="haiku"),
    ])
    async def model_cmd(
        interaction: discord.Interaction,
        choice: app_commands.Choice[str] | None = None,
    ) -> None:
        channel_id = str(interaction.channel_id)
        if choice is None:
            # Show current model and available models
            session = get_active_session(channel_id)
            if session:
                current = session.get("model", "unknown")
            else:
                current = config.get("bot.default_model", "sonnet")
            available = ", ".join(sorted(VALID_MODELS))
            await interaction.response.send_message(
                f"**Current model:** {current}\n"
                f"**Available:** {available}",
                ephemeral=True,
            )
        else:
            model = choice.value
            session = get_active_session(channel_id)
            if session:
                set_session_model(channel_id, model)
            else:
                # No session yet — pre-set in active.json so next message uses it
                from src.claude_session import _load_sessions, _save_sessions
                from datetime import datetime, timezone
                sessions = _load_sessions()
                sessions[channel_id] = {
                    "session_id": "",
                    "model": model,
                    "created_at": datetime.now(timezone.utc).isoformat(),
                    "last_message_at": datetime.now(timezone.utc).isoformat(),
                    "message_count": 0,
                }
                _save_sessions(sessions)
            await interaction.response.send_message(
                f"Model changed to **{model}**.", ephemeral=True
            )

    @tree.command(name="restart", description="Restart the bot process")
    async def restart(interaction: discord.Interaction) -> None:
        if not is_owner(str(interaction.user.id)):
            await interaction.response.send_message(
                "Owner only.", ephemeral=True
            )
            return
        pid_file = PROJECT_ROOT / "echo-core.pid"
        if not pid_file.exists():
            await interaction.response.send_message(
                "No PID file found (echo-core.pid).", ephemeral=True
            )
            return
        try:
            pid = int(pid_file.read_text().strip())
            os.kill(pid, signal.SIGTERM)
            await interaction.response.send_message(
                "Restarting...", ephemeral=True
            )
        except ProcessLookupError:
            await interaction.response.send_message(
                f"Process {pid} not found.", ephemeral=True
            )
        except ValueError:
            await interaction.response.send_message(
                "Invalid PID file content.", ephemeral=True
            )

    @tree.command(name="logs", description="Show recent log lines")
    @app_commands.describe(n="Number of lines to show (default 10)")
    async def logs_cmd(
        interaction: discord.Interaction, n: int = 10
    ) -> None:
        log_path = PROJECT_ROOT / "logs" / "echo-core.log"
        if not log_path.exists():
            await interaction.response.send_message(
                "No log file found.", ephemeral=True
            )
            return
        try:
            all_lines = log_path.read_text(encoding="utf-8").splitlines()
            tail = all_lines[-n:] if len(all_lines) >= n else all_lines
            text = "\n".join(tail)
            # Truncate to fit Discord message limit (2000 - code block overhead)
            if len(text) > 1900:
                text = text[-1900:]
            await interaction.response.send_message(
                f"```\n{text}\n```", ephemeral=True
            )
        except Exception as e:
            await interaction.response.send_message(
                f"Error reading logs: {e}", ephemeral=True
            )

    # --- Events ---

    @client.event
    async def on_ready() -> None:
        await tree.sync()
        scheduler = getattr(client, "scheduler", None)
        if scheduler is not None:
            await scheduler.start()
        logger.info("Echo Core online as %s", client.user)

    async def _handle_chat(message: discord.Message) -> None:
        """Process a chat message through the router and send the response."""
        channel_id = str(message.channel.id)
        user_id = str(message.author.id)
        text = message.content

        # React to acknowledge receipt
        await message.add_reaction("\U0001f440")

        try:
            async with message.channel.typing():
                response, _is_cmd = await asyncio.to_thread(
                    route_message, channel_id, user_id, text
                )

            chunks = split_message(response)
            for chunk in chunks:
                await message.channel.send(chunk)
        except Exception:
            logger.exception("Error processing message from %s", message.author)
            await message.channel.send(
                "Sorry, something went wrong processing your message."
            )
        finally:
            # Remove the eyes reaction
            try:
                await message.remove_reaction("\U0001f440", client.user)
            except discord.HTTPException:
                pass

    @client.event
    async def on_message(message: discord.Message) -> None:
        # Ignore bot's own messages
        if message.author == client.user:
            return

        # DM handling: only process if sender is admin
        if isinstance(message.channel, discord.DMChannel):
            if not is_admin(str(message.author.id)):
                return
            logger.info(
                "DM from admin %s: %s", message.author, message.content[:100]
            )
            await _handle_chat(message)
            return

        # Guild messages: ignore if channel not registered
        if not is_registered_channel(str(message.channel.id)):
            return

        logger.info(
            "Message in registered channel %s from %s: %s",
            message.channel,
            message.author,
            message.content[:100],
        )
        await _handle_chat(message)

    return client