import asyncio
from contextlib import asynccontextmanager
from datetime import datetime, timezone
from typing import Optional

from fastapi import FastAPI
from app.config import settings
from app.models import SystemConfig
from app.internal.logger import logger
from app.internal.mqtt_manager import mqtt_manager
from app.internal import credentials
from app.internal.metadata_watcher import metadata_watcher
from app.internal.call_recorder import call_recorder
from app.internal.discord_radio import radio_bot
from app.internal.config_manager import (
    load_node_config,
    save_node_config,
)
from app.routers import api, ui


# ---------------------------------------------------------------------------
# Event handlers wired up at startup
# ---------------------------------------------------------------------------

def _iso(epoch: Optional[float]) -> Optional[str]:
    """Epoch → UTC ISO-8601, matching metadata_watcher's timestamp format."""
    if epoch is None:
        return None
    return datetime.fromtimestamp(epoch, timezone.utc).isoformat()


async def on_call_start(data: dict):
    radio_bot.start_stream()
    await mqtt_manager.publish_status("recording")
    await mqtt_manager.publish_metadata("call_start", data)
    # started_at_epoch is OP25's own call_log timestamp — the recorder slices the
    # ring buffer back to it (minus pre-roll), so however late we detected the
    # grant, the audio still starts in the right place.
    await call_recorder.start_recording(
        data["call_id"],
        start_epoch=data.get("started_at_epoch"),
    )


async def on_call_end(data: dict):
    radio_bot.stop_stream()
    recording = await call_recorder.stop_recording(end_epoch=data.get("ended_at_epoch"))

    if recording is not None and recording.path is not None:
        # Silence trimming shortens the audio, so the audio's own bounds no
        # longer equal the call's. `started_at`/`ended_at` keep meaning the CALL
        # (what OP25 observed on the control channel) — these extra fields carry
        # the AUDIO's wall-clock bounds so playback, correlation and incident
        # timelines can still map an audio offset back to real time:
        #     wall_clock_of(audio_offset_t) == audio_start_epoch + t
        data["audio_start_at"] = _iso(recording.audio_start_epoch)
        data["audio_end_at"] = _iso(recording.audio_end_epoch)
        data["audio_start_epoch"] = recording.audio_start_epoch
        data["audio_end_epoch"] = recording.audio_end_epoch
        data["audio_lead_trimmed"] = round(recording.lead_trimmed, 3)
        data["audio_tail_trimmed"] = round(recording.tail_trimmed, 3)
        if recording.clamped_seconds:
            data["audio_clamped_seconds"] = round(recording.clamped_seconds, 3)

    if recording is not None and recording.path is not None:
        node_cfg = load_node_config()
        audio_url = await call_recorder.upload_recording(
            recording.path,
            data["call_id"],
            talkgroup_id=data.get("tgid"),
            talkgroup_name=data.get("tgid_name"),
            system_id=node_cfg.assigned_system_id,
            audio_start_epoch=recording.audio_start_epoch,
            audio_end_epoch=recording.audio_end_epoch,
        )
        if audio_url:
            data["audio_url"] = audio_url
        else:
            logger.error(f"Audio upload failed for call {data['call_id']}. Verify C2_URL and Node API Key.")
    elif recording is not None and recording.all_silence:
        # Explicit policy: an all-silence recording is not uploaded. It has no
        # transcript value and silence is what makes Whisper invent text.
        data["audio_skipped"] = "all_silence"
        logger.warning(f"Call {data['call_id']} was pure silence — no upload. Investigate the audio path.")
    else:
        logger.warning(
            f"No recording file generated for call {data['call_id']} "
            "— PulseAudio capture may be down (check the op25 container and "
            f"the {settings.pulse_source} source)."
        )
    await mqtt_manager.publish_metadata("call_end", data)
    await mqtt_manager.publish_status("online")


async def on_command(payload: dict):
    action = payload.get("action")
    logger.info(f"Command received: {action}")

    if action == "discord_join":
        token = payload.get("token")
        if not token:
            logger.error("discord_join command missing token — ignoring.")
            return
        await radio_bot.join(
            guild_id=int(payload["guild_id"]),
            channel_id=int(payload["channel_id"]),
            token=token,
            call_active=metadata_watcher.is_active,
            system_name=payload.get("system_name"),
        )
    elif action == "discord_leave":
        await radio_bot.leave()
    elif action == "op25_restart":
        from app.internal.op25_client import op25_client
        await op25_client.stop()
        await asyncio.sleep(2)
        await op25_client.start()
    elif action == "node_update":
        # TODO: Full OTA update — register a host-level systemd service (e.g. drb-update.service)
        # that stops all DRB containers, runs `docker compose pull`, then `docker compose up -d`.
        # The C2 server triggers it by sending this MQTT command; the host service watches for the
        # restart signal (e.g. via a Unix socket, a sentinel file, or a lightweight webhook).
        # Not implemented yet — for now, just restart the container so any pre-pulled image
        # is picked up (requires a prior `docker compose pull` on the host).
        logger.info("Node update requested — restarting container to pick up latest image.")
        await mqtt_manager.publish_status("offline")
        await asyncio.sleep(1)
        import os
        os._exit(0)  # Docker restart=unless-stopped will bring the container back up
    else:
        logger.warning(f"Unknown command: {action}")


async def on_api_key(payload: dict):
    key = payload.get("api_key")
    if key:
        credentials.save_api_key(key)
        logger.info("Node API key received and saved.")


def _to_hz(freq) -> int:
    """Convert a frequency to Hz. Accepts MHz floats (< 1e6) or Hz ints."""
    f = float(freq)
    return int(f * 1_000_000) if f < 1_000_000 else int(f)


async def _generate_op25_config(config: SystemConfig) -> bool:
    """Translate a SystemConfig (Firestore format) into OP25 active.cfg.json + op25.liq."""
    from app.internal.op25_client import op25_client
    node_cfg = load_node_config()
    raw = config.config
    payload = {
        "type": config.type,
        "systemName": config.name,
        "channels": [_to_hz(ch) for ch in raw.get("control_channels", [])],
        "tags": [
            {"talkgroup": str(tg.get("name", "")), "tagDec": int(tg["id"])}
            for tg in raw.get("talkgroups", [])
            if tg.get("id") is not None
        ],
        "whitelist": [int(tg["id"]) for tg in raw.get("talkgroups", []) if tg.get("id") is not None],
        "icecastConfig": {
            "icecast_host": settings.icecast_host,
            "icecast_port": settings.icecast_port,
            "icecast_mountpoint": settings.icecast_mount,
            "icecast_password": settings.icecast_source_password,
        },
        "hardware_preset": node_cfg.hardware_preset,
        **({"ppm_override": node_cfg.ppm_override} if node_cfg.ppm_override is not None else {}),
    }
    return await op25_client.generate_config(payload)


async def on_config_push(payload: dict):
    """C2 pushes a system config — translate it to OP25 format and restart OP25."""
    hardware_preset = payload.pop("hardware_preset", None)
    ppm_override = payload.pop("ppm_override", None)
    node_type = payload.pop("node_type", None)
    enforce_override_timeout = payload.pop("enforce_override_timeout", None)
    try:
        config = SystemConfig(**payload)
    except Exception as e:
        logger.error(f"Invalid config push payload: {e}")
        return

    node_cfg = load_node_config()
    node_cfg.assigned_system_id = config.system_id
    node_cfg.system_config = config
    node_cfg.configured = True
    node_cfg.override_system_id = None
    node_cfg.override_config = None
    if hardware_preset is not None:
        node_cfg.hardware_preset = hardware_preset
    if ppm_override is not None:
        node_cfg.ppm_override = float(ppm_override)
    if node_type is not None:
        node_cfg.node_type = node_type
    if enforce_override_timeout is not None:
        node_cfg.enforce_override_timeout = bool(enforce_override_timeout)
    save_node_config(node_cfg)

    from app.internal.op25_client import op25_client
    if not await _generate_op25_config(config):
        logger.error(f"Failed to generate OP25 config for {config.name}")
        return

    await op25_client.stop()
    await asyncio.sleep(2)
    await op25_client.start()
    logger.info(f"Config push applied: {config.name}")


# ---------------------------------------------------------------------------
# App lifecycle
# ---------------------------------------------------------------------------

@asynccontextmanager
async def lifespan(app: FastAPI):
    logger.info(f"Edge node starting — ID: {settings.node_id}")

    # Load persisted credentials (API key provisioned by C2 after approval)
    credentials.load()

    # Wire callbacks
    metadata_watcher.on_call_start = on_call_start
    metadata_watcher.on_call_end = on_call_end
    mqtt_manager.on_command = on_command
    mqtt_manager.on_config_push = on_config_push
    mqtt_manager.on_api_key = on_api_key

    # Start services (radio_bot starts on-demand when a discord_join command arrives)
    await mqtt_manager.connect()
    await metadata_watcher.start()
    await call_recorder.start()  # persistent PulseAudio ring buffer

    # Start system caching in background
    from app.internal.system_cacher import fetch_and_cache_systems
    asyncio.create_task(fetch_and_cache_systems())

    # Report initial status and resume OP25 if node was already configured before this restart
    node_cfg = load_node_config()
    initial_status = "online" if node_cfg.configured else "unconfigured"
    await mqtt_manager.publish_status(initial_status)

    active_config = node_cfg.override_config if (node_cfg.override_system_id and node_cfg.override_config) else node_cfg.system_config
    if node_cfg.configured and active_config:
        from app.internal.op25_client import op25_client
        logger.info("Node is configured — waiting for OP25 API then generating config.")
        for attempt in range(10):
            if await _generate_op25_config(active_config):
                await op25_client.start()
                break
            logger.warning(f"OP25 not ready yet (attempt {attempt + 1}/10), retrying in 3s…")
            await asyncio.sleep(3)

    heartbeat_task = asyncio.create_task(mqtt_manager.heartbeat_loop())

    yield  # --- app running ---

    logger.info("Edge node shutting down.")
    heartbeat_task.cancel()
    await metadata_watcher.stop()
    await call_recorder.stop()
    await radio_bot.stop()
    await mqtt_manager.disconnect()


app = FastAPI(title=f"DRB Edge Node — {settings.node_id}", lifespan=lifespan)
app.include_router(api.router)
app.include_router(ui.router)