"""AIS vessel tracking routes."""

from __future__ import annotations

import json
import os
import queue
import shutil
import socket
import subprocess
import threading
import time
from typing import Generator

from flask import Blueprint, jsonify, request, Response, render_template

import app as app_module
from config import SHARED_OBSERVER_LOCATION_ENABLED
from utils.logging import get_logger
from utils.validation import validate_device_index, validate_gain
from utils.sse import sse_stream_fanout
from utils.event_pipeline import process_event
from utils.sdr import SDRFactory, SDRType
from utils.constants import (
    AIS_TCP_PORT,
    AIS_TERMINATE_TIMEOUT,
    AIS_SOCKET_TIMEOUT,
    AIS_RECONNECT_DELAY,
    AIS_UPDATE_INTERVAL,
    SOCKET_BUFFER_SIZE,
    SSE_KEEPALIVE_INTERVAL,
    SSE_QUEUE_TIMEOUT,
    SOCKET_CONNECT_TIMEOUT,
    PROCESS_TERMINATE_TIMEOUT,
)

logger = get_logger('intercept.ais')

ais_bp = Blueprint('ais', __name__, url_prefix='/ais')

# Track AIS state
ais_running = False
ais_connected = False
ais_messages_received = 0
ais_last_message_time = None
ais_active_device = None
ais_active_sdr_type: str | None = None
_ais_error_logged = True

# Common installation paths for AIS-catcher
AIS_CATCHER_PATHS = [
    '/usr/local/bin/AIS-catcher',
    '/usr/bin/AIS-catcher',
    '/opt/homebrew/bin/AIS-catcher',
    '/opt/homebrew/bin/aiscatcher',
]


def find_ais_catcher():
    """Find AIS-catcher binary, checking PATH and common locations."""
    # First try PATH
    for name in ['AIS-catcher', 'aiscatcher']:
        path = shutil.which(name)
        if path:
            return path
    # Check common installation paths
    for path in AIS_CATCHER_PATHS:
        if os.path.isfile(path) and os.access(path, os.X_OK):
            return path
    return None


def parse_ais_stream(port: int):
    """Parse JSON data from AIS-catcher TCP server."""
    global ais_running, ais_connected, ais_messages_received, ais_last_message_time, _ais_error_logged

    logger.info(f"AIS stream parser started, connecting to localhost:{port}")
    ais_connected = True
    ais_messages_received = 0
    _ais_error_logged = True

    while ais_running:
        sock = None
        try:
            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            sock.settimeout(AIS_SOCKET_TIMEOUT)
            sock.connect(('localhost', port))
            ais_connected = True
            _ais_error_logged = True
            logger.info("Connected to AIS-catcher TCP server")

            buffer = ""
            last_update = time.time()
            pending_updates = set()

            while ais_running:
                try:
                    data = sock.recv(SOCKET_BUFFER_SIZE).decode('utf-8', errors='ignore')
                    if not data:
                        logger.warning("AIS connection closed (no data)")
                        break
                    buffer += data

                    while '\n' in buffer:
                        line, buffer = buffer.split('\n', 1)
                        line = line.strip()
                        if not line:
                            continue

                        try:
                            msg = json.loads(line)
                            vessel = process_ais_message(msg)
                            if vessel:
                                mmsi = vessel.get('mmsi')
                                if mmsi:
                                    app_module.ais_vessels.set(mmsi, vessel)
                                    pending_updates.add(mmsi)
                                    ais_messages_received += 1
                                    ais_last_message_time = time.time()
                        except json.JSONDecodeError:
                            if ais_messages_received < 5:
                                logger.debug(f"Invalid JSON: {line[:100]}")

                    # Batch updates
                    now = time.time()
                    if now - last_update >= AIS_UPDATE_INTERVAL:
                        for mmsi in pending_updates:
                            if mmsi in app_module.ais_vessels:
                                _vessel_snap = app_module.ais_vessels[mmsi]
                                try:
                                    app_module.ais_queue.put_nowait({
                                        'type': 'vessel',
                                        **_vessel_snap
                                    })
                                except queue.Full:
                                    pass
                                # Geofence check
                                _v_lat = _vessel_snap.get('lat')
                                _v_lon = _vessel_snap.get('lon')
                                if _v_lat and _v_lon:
                                    try:
                                        from utils.geofence import get_geofence_manager
                                        for _gf_evt in get_geofence_manager().check_position(
                                            mmsi, 'vessel', _v_lat, _v_lon,
                                            {'name': _vessel_snap.get('name'), 'ship_type': _vessel_snap.get('ship_type_text')}
                                        ):
                                            process_event('ais', _gf_evt, 'geofence')
                                    except Exception:
                                        pass
                        pending_updates.clear()
                        last_update = now

                except socket.timeout:
                    continue

            ais_connected = False
        except OSError as e:
            ais_connected = False
            if not _ais_error_logged:
                logger.warning(f"AIS connection error: {e}, reconnecting...")
                _ais_error_logged = True
            time.sleep(AIS_RECONNECT_DELAY)
        finally:
            if sock:
                try:
                    sock.close()
                except OSError:
                    pass

    ais_connected = False
    logger.info("AIS stream parser stopped")


def process_ais_message(msg: dict) -> dict | None:
    """Process AIS-catcher JSON message and extract vessel data."""
    # AIS-catcher outputs different message types
    # We're interested in position reports and static data

    mmsi = msg.get('mmsi')
    if not mmsi:
        return None

    mmsi = str(mmsi)

    # Get existing vessel data or create new
    vessel = app_module.ais_vessels.get(mmsi) or {'mmsi': mmsi}

    # Extract common fields
    # AIS-catcher JSON_FULL uses 'longitude'/'latitude', but some versions use 'lon'/'lat'
    lat_val = msg.get('latitude') or msg.get('lat')
    lon_val = msg.get('longitude') or msg.get('lon')
    if lat_val is not None and lon_val is not None:
        try:
            lat = float(lat_val)
            lon = float(lon_val)
            # Validate coordinates (AIS uses 181 for unavailable)
            if -90 <= lat <= 90 and -180 <= lon <= 180:
                vessel['lat'] = lat
                vessel['lon'] = lon
        except (ValueError, TypeError):
            pass

    # Speed over ground (knots)
    if 'speed' in msg:
        try:
            speed = float(msg['speed'])
            if speed < 102.3:  # 102.3 = not available
                vessel['speed'] = round(speed, 1)
        except (ValueError, TypeError):
            pass

    # Course over ground (degrees)
    if 'course' in msg:
        try:
            course = float(msg['course'])
            if course < 360:  # 360 = not available
                vessel['course'] = round(course, 1)
        except (ValueError, TypeError):
            pass

    # True heading (degrees)
    if 'heading' in msg:
        try:
            heading = int(msg['heading'])
            if heading < 511:  # 511 = not available
                vessel['heading'] = heading
        except (ValueError, TypeError):
            pass

    # Navigation status
    if 'status' in msg:
        vessel['nav_status'] = msg['status']
    if 'status_text' in msg:
        vessel['nav_status_text'] = msg['status_text']

    # Vessel name (from Type 5 or Type 24 messages)
    if 'shipname' in msg:
        name = msg['shipname'].strip().strip('@')
        if name:
            vessel['name'] = name

    # Callsign
    if 'callsign' in msg:
        callsign = msg['callsign'].strip().strip('@')
        if callsign:
            vessel['callsign'] = callsign

    # Ship type
    if 'shiptype' in msg:
        vessel['ship_type'] = msg['shiptype']
    if 'shiptype_text' in msg:
        vessel['ship_type_text'] = msg['shiptype_text']

    # Destination
    if 'destination' in msg:
        dest = msg['destination'].strip().strip('@')
        if dest:
            vessel['destination'] = dest

    # ETA
    if 'eta' in msg:
        vessel['eta'] = msg['eta']

    # Dimensions
    if 'to_bow' in msg and 'to_stern' in msg:
        try:
            length = int(msg['to_bow']) + int(msg['to_stern'])
            if length > 0:
                vessel['length'] = length
        except (ValueError, TypeError):
            pass

    if 'to_port' in msg and 'to_starboard' in msg:
        try:
            width = int(msg['to_port']) + int(msg['to_starboard'])
            if width > 0:
                vessel['width'] = width
        except (ValueError, TypeError):
            pass

    # Draught
    if 'draught' in msg:
        try:
            draught = float(msg['draught'])
            if draught > 0:
                vessel['draught'] = draught
        except (ValueError, TypeError):
            pass

    # Rate of turn
    if 'turn' in msg:
        try:
            turn = float(msg['turn'])
            if -127 <= turn <= 127:  # Valid range
                vessel['rate_of_turn'] = turn
        except (ValueError, TypeError):
            pass

    # Message type for debugging
    if 'type' in msg:
        vessel['last_msg_type'] = msg['type']

    # Timestamp
    vessel['last_seen'] = time.time()

    # Check for DSC DISTRESS matching this MMSI
    try:
        for _dsc_key, _dsc_msg in app_module.dsc_messages.items():
            if (str(_dsc_msg.get('source_mmsi', '')) == mmsi
                    and _dsc_msg.get('category', '').upper() == 'DISTRESS'):
                vessel['dsc_distress'] = True
                break
    except Exception:
        pass

    return vessel


@ais_bp.route('/tools')
def check_ais_tools():
    """Check for AIS decoding tools and hardware."""
    has_ais_catcher = find_ais_catcher() is not None

    # Check what SDR hardware is detected
    devices = SDRFactory.detect_devices()
    has_rtlsdr = any(d.sdr_type == SDRType.RTL_SDR for d in devices)

    return jsonify({
        'ais_catcher': has_ais_catcher,
        'ais_catcher_path': find_ais_catcher(),
        'has_rtlsdr': has_rtlsdr,
        'device_count': len(devices)
    })


@ais_bp.route('/status')
def ais_status():
    """Get AIS tracking status for debugging."""
    process_running = False
    if app_module.ais_process:
        process_running = app_module.ais_process.poll() is None

    return jsonify({
        'tracking_active': ais_running,
        'active_device': ais_active_device,
        'connected': ais_connected,
        'messages_received': ais_messages_received,
        'last_message_time': ais_last_message_time,
        'vessel_count': len(app_module.ais_vessels),
        'vessels': dict(app_module.ais_vessels),
        'queue_size': app_module.ais_queue.qsize(),
        'ais_catcher_path': find_ais_catcher(),
        'process_running': process_running
    })


@ais_bp.route('/start', methods=['POST'])
def start_ais():
    """Start AIS tracking."""
    global ais_running, ais_active_device, ais_active_sdr_type

    with app_module.ais_lock:
        if ais_running:
            return jsonify({'status': 'already_running', 'message': 'AIS tracking already active'}), 409

    data = request.json or {}

    # Validate inputs
    try:
        gain = int(validate_gain(data.get('gain', '40')))
        device = validate_device_index(data.get('device', '0'))
    except ValueError as e:
        return jsonify({'status': 'error', 'message': str(e)}), 400

    # Find AIS-catcher
    ais_catcher_path = find_ais_catcher()
    if not ais_catcher_path:
        return jsonify({
            'status': 'error',
            'message': 'AIS-catcher not found. Install from https://github.com/jvde-github/AIS-catcher/releases'
        }), 400

    # Get SDR type from request
    sdr_type_str = data.get('sdr_type', 'rtlsdr')
    try:
        sdr_type = SDRType(sdr_type_str)
    except ValueError:
        sdr_type = SDRType.RTL_SDR

    # Kill any existing process
    if app_module.ais_process:
        try:
            pgid = os.getpgid(app_module.ais_process.pid)
            os.killpg(pgid, 15)
            app_module.ais_process.wait(timeout=PROCESS_TERMINATE_TIMEOUT)
        except (subprocess.TimeoutExpired, ProcessLookupError, OSError):
            try:
                pgid = os.getpgid(app_module.ais_process.pid)
                os.killpg(pgid, 9)
            except (ProcessLookupError, OSError):
                pass
        app_module.ais_process = None
        logger.info("Killed existing AIS process")

    # Check if device is available
    device_int = int(device)
    error = app_module.claim_sdr_device(device_int, 'ais', sdr_type_str)
    if error:
        return jsonify({
            'status': 'error',
            'error_type': 'DEVICE_BUSY',
            'message': error
        }), 409

    # Build command using SDR abstraction
    sdr_device = SDRFactory.create_default_device(sdr_type, index=device)
    builder = SDRFactory.get_builder(sdr_type)

    bias_t = data.get('bias_t', False)
    tcp_port = AIS_TCP_PORT

    cmd = builder.build_ais_command(
        device=sdr_device,
        gain=float(gain),
        bias_t=bias_t,
        tcp_port=tcp_port
    )

    # Use the found AIS-catcher path
    cmd[0] = ais_catcher_path

    try:
        logger.info(f"Starting AIS-catcher with device {device}: {' '.join(cmd)}")
        app_module.ais_process = subprocess.Popen(
            cmd,
            stdout=subprocess.DEVNULL,
            stderr=subprocess.PIPE,
            start_new_session=True
        )

        # Wait for process to start
        time.sleep(2.0)

        if app_module.ais_process.poll() is not None:
            # Release device on failure
            app_module.release_sdr_device(device_int, sdr_type_str)
            stderr_output = ''
            if app_module.ais_process.stderr:
                try:
                    stderr_output = app_module.ais_process.stderr.read().decode('utf-8', errors='ignore').strip()
                except Exception:
                    pass
            error_msg = 'AIS-catcher failed to start. Check SDR device connection.'
            if stderr_output:
                error_msg += f' Error: {stderr_output[:200]}'
            return jsonify({'status': 'error', 'message': error_msg}), 500

        ais_running = True
        ais_active_device = device
        ais_active_sdr_type = sdr_type_str

        # Start TCP parser thread
        thread = threading.Thread(target=parse_ais_stream, args=(tcp_port,), daemon=True)
        thread.start()

        return jsonify({
            'status': 'started',
            'message': 'AIS tracking started',
            'device': device,
            'port': tcp_port
        })
    except Exception as e:
        # Release device on failure
        app_module.release_sdr_device(device_int, sdr_type_str)
        logger.error(f"Failed to start AIS-catcher: {e}")
        return jsonify({'status': 'error', 'message': str(e)}), 500


@ais_bp.route('/stop', methods=['POST'])
def stop_ais():
    """Stop AIS tracking."""
    global ais_running, ais_active_device, ais_active_sdr_type

    with app_module.ais_lock:
        if app_module.ais_process:
            try:
                pgid = os.getpgid(app_module.ais_process.pid)
                os.killpg(pgid, 15)
                app_module.ais_process.wait(timeout=AIS_TERMINATE_TIMEOUT)
            except (subprocess.TimeoutExpired, ProcessLookupError, OSError):
                try:
                    pgid = os.getpgid(app_module.ais_process.pid)
                    os.killpg(pgid, 9)
                except (ProcessLookupError, OSError):
                    pass
            app_module.ais_process = None
            logger.info("AIS process stopped")

        # Release device from registry
        if ais_active_device is not None:
            app_module.release_sdr_device(ais_active_device, ais_active_sdr_type or 'rtlsdr')

        ais_running = False
        ais_active_device = None
        ais_active_sdr_type = None

    app_module.ais_vessels.clear()
    return jsonify({'status': 'stopped'})


@ais_bp.route('/stream')
def stream_ais():
    """SSE stream for AIS vessels."""
    def _on_msg(msg: dict[str, Any]) -> None:
        process_event('ais', msg, msg.get('type'))

    response = Response(
        sse_stream_fanout(
            source_queue=app_module.ais_queue,
            channel_key='ais',
            timeout=SSE_QUEUE_TIMEOUT,
            keepalive_interval=SSE_KEEPALIVE_INTERVAL,
            on_message=_on_msg,
        ),
        mimetype='text/event-stream',
    )
    response.headers['Cache-Control'] = 'no-cache'
    response.headers['X-Accel-Buffering'] = 'no'
    return response


@ais_bp.route('/vessel/<mmsi>/dsc')
def get_vessel_dsc(mmsi: str):
    """Get DSC messages associated with a vessel MMSI."""
    if not mmsi or not mmsi.isdigit():
        return jsonify({'status': 'error', 'message': 'Invalid MMSI'}), 400

    matches = []
    try:
        for key, msg in app_module.dsc_messages.items():
            if str(msg.get('source_mmsi', '')) == mmsi:
                matches.append(dict(msg))
    except Exception:
        pass

    return jsonify({'status': 'success', 'mmsi': mmsi, 'dsc_messages': matches})


@ais_bp.route('/dashboard')
def ais_dashboard():
    """Popout AIS dashboard."""
    embedded = request.args.get('embedded', 'false') == 'true'
    return render_template(
        'ais_dashboard.html',
        shared_observer_location=SHARED_OBSERVER_LOCATION_ENABLED,
        embedded=embedded,
    )