import fs from 'node:fs';
import path from 'node:path';
import { transaction } from '../database.js';
import { config } from '../config.js';
import { HttpError } from '../middleware/errors.js';
import { parseGpx } from './gpx.js';
import { distanceMeters, routeMetrics } from './geo.js';
import {
  ensureRouteDirectories, moveUploadedFile, routeDirectory,
  softDeleteRouteDirectory, restoreRouteDirectory, resolveStoredFile, removeUpload
} from './storage.js';

const slugify = value => value.toLowerCase().normalize('NFKD').replace(/[\u0300-\u036f]/g, '').replace(/[^a-z0-9]+/g, '-').replace(/^-|-$/g, '').slice(0, 80) || `route-${Date.now()}`;
const routeGpxUrl = routeId => `/api/routes/${routeId}/gpx`;
const pictureUrl = (routeId, poiId, pictureId) => `/api/routes/${routeId}/pois/${poiId}/pictures/${pictureId}`;
const audioUrl = (routeId, poiId) => `/api/routes/${routeId}/pois/${poiId}/audio`;
function rowToRoute(row, includeDeleted = false) {
  if (!row || (!includeDeleted && row.status !== 'active')) return null;
  return {
    id: row.id, slug: row.slug, name: row.name, description: row.description,
    schoolName: row.school_name, status: row.status,
    start: row.start_lat == null ? null : { lat: row.start_lat, lon: row.start_lon },
    center: row.center_lat == null ? null : { lat: row.center_lat, lon: row.center_lon },
    bounds: row.min_lat == null ? null : { minLat: row.min_lat, minLon: row.min_lon, maxLat: row.max_lat, maxLon: row.max_lon },
    distanceM: row.distance_m, elevationGainM: row.elevation_gain_m, pointCount: row.point_count,
    gpxUrl: row.gpx_path && row.status === 'active' ? routeGpxUrl(row.id) : null,
    createdAt: row.created_at, updatedAt: row.updated_at, deletedAt: row.deleted_at
  };
}

export function listRoutes(db, { lat, lon, radiusKm = config.defaultRouteRadiusKm, includeDeleted = false }) {
  const rows = db.prepare(`SELECT * FROM routes ${includeDeleted ? '' : "WHERE status = 'active'"} ORDER BY name COLLATE NOCASE`).all();
  const origin = Number.isFinite(lat) && Number.isFinite(lon) ? { lat, lon } : null;
  return rows.map(row => {
    const route = rowToRoute(row, includeDeleted);
    const proximityM = origin && route.start ? distanceMeters(origin, route.start) : null;
    return { ...route, proximityM };
  }).filter(route => !origin || route.proximityM <= radiusKm * 1000).sort((a, b) => origin ? a.proximityM - b.proximityM : a.name.localeCompare(b.name, 'de'));
}

export function getRoute(db, id, includeDeleted = false) {
  const route = rowToRoute(db.prepare('SELECT * FROM routes WHERE id = ?').get(id), includeDeleted);
  if (!route) throw new HttpError(404, 'Strecke nicht gefunden.');
  const points = db.prepare('SELECT sequence, lat, lon, elevation, recorded_at AS recordedAt FROM route_points WHERE route_id = ? ORDER BY sequence').all(id);
  const pois = listPois(db, id);
  return { ...route, points, pois };
}

export function getRouteGpxFile(db, id) {
  const route = db.prepare("SELECT id, slug, gpx_path FROM routes WHERE id = ? AND status = 'active'").get(id);
  if (!route) throw new HttpError(404, 'Strecke nicht gefunden.');
  return {
    absolutePath: resolveStoredFile(route.gpx_path),
    filename: `${route.slug}.gpx`
  };
}

export function createRoute(db, fields, gpxFile) {
  if (!gpxFile) throw new HttpError(400, 'Eine GPX-Datei ist erforderlich.');
  const parsed = parseGpx(fs.readFileSync(gpxFile.path, 'utf8'));
  const name = String(fields.name || parsed.name || '').trim();
  if (!name) throw new HttpError(400, 'Ein Streckenname ist erforderlich.');
  let routeId;
  let finalGpx;
  try {
    routeId = transaction(db, () => {
      let slug = slugify(fields.slug || name);
      let suffix = 2;
      while (db.prepare('SELECT 1 FROM routes WHERE slug = ?').get(slug)) slug = `${slugify(fields.slug || name)}-${suffix++}`;
      const result = db.prepare(`INSERT INTO routes
        (slug, name, description, school_name, gpx_path, start_lat, start_lon, center_lat, center_lon, min_lat, min_lon, max_lat, max_lon, distance_m, elevation_gain_m, point_count)
        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`)
        .run(slug, name, fields.description || '', fields.schoolName || '', 'pending', parsed.metrics.startLat, parsed.metrics.startLon,
          parsed.metrics.centerLat, parsed.metrics.centerLon, parsed.metrics.minLat, parsed.metrics.minLon, parsed.metrics.maxLat, parsed.metrics.maxLon,
          parsed.metrics.distanceM, parsed.metrics.elevationGainM, parsed.metrics.pointCount);
      const id = Number(result.lastInsertRowid);
      const insertPoint = db.prepare('INSERT INTO route_points (route_id, sequence, lat, lon, elevation, recorded_at) VALUES (?, ?, ?, ?, ?, ?)');
      for (const point of parsed.points) insertPoint.run(id, point.sequence, point.lat, point.lon, point.elevation, point.recordedAt);
      return id;
    });
    ensureRouteDirectories(routeId);
    finalGpx = path.join(routeDirectory(routeId), 'route.gpx');
    const gpxPath = moveUploadedFile(gpxFile, finalGpx);
    db.prepare("UPDATE routes SET gpx_path = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?").run(gpxPath, routeId);
    return getRoute(db, routeId);
  } catch (error) {
    removeUpload(gpxFile);
    if (routeId) {
      db.prepare('DELETE FROM route_points WHERE route_id = ?').run(routeId);
      db.prepare('DELETE FROM routes WHERE id = ?').run(routeId);
      fs.rmSync(routeDirectory(routeId), { recursive: true, force: true });
    }
    throw error;
  }
}

export function updateRoute(db, id, fields, gpxFile) {
  const existing = db.prepare("SELECT * FROM routes WHERE id = ? AND status = 'active'").get(id);
  if (!existing) throw new HttpError(404, 'Strecke nicht gefunden.');
  let parsed = null;
  if (gpxFile) parsed = parseGpx(fs.readFileSync(gpxFile.path, 'utf8'));
  transaction(db, () => {
    db.prepare(`UPDATE routes SET name = ?, description = ?, school_name = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?`)
      .run(fields.name ?? existing.name, fields.description ?? existing.description, fields.schoolName ?? existing.school_name, id);
    if (parsed) {
      db.prepare('DELETE FROM route_points WHERE route_id = ?').run(id);
      const insertPoint = db.prepare('INSERT INTO route_points (route_id, sequence, lat, lon, elevation, recorded_at) VALUES (?, ?, ?, ?, ?, ?)');
      for (const point of parsed.points) insertPoint.run(id, point.sequence, point.lat, point.lon, point.elevation, point.recordedAt);
      const m = parsed.metrics;
      db.prepare(`UPDATE routes SET start_lat=?, start_lon=?, center_lat=?, center_lon=?, min_lat=?, min_lon=?, max_lat=?, max_lon=?, distance_m=?, elevation_gain_m=?, point_count=? WHERE id=?`)
        .run(m.startLat, m.startLon, m.centerLat, m.centerLon, m.minLat, m.minLon, m.maxLat, m.maxLon, m.distanceM, m.elevationGainM, m.pointCount, id);
    }
  });
  if (gpxFile) moveUploadedFile(gpxFile, path.join(routeDirectory(id), 'route.gpx'));
  return getRoute(db, id);
}

export function appendRoute(db, id, gpxFile) {
  if (!gpxFile) throw new HttpError(400, 'Eine GPX-Datei ist erforderlich.');
  const existing = db.prepare("SELECT * FROM routes WHERE id = ? AND status = 'active'").get(id);
  if (!existing) throw new HttpError(404, 'Strecke nicht gefunden.');
  const parsed = parseGpx(fs.readFileSync(gpxFile.path, 'utf8'));
  const current = db.prepare('SELECT lat, lon, elevation, recorded_at AS recordedAt FROM route_points WHERE route_id = ? ORDER BY sequence').all(id);
  const all = current.concat(parsed.points).map((point, sequence) => ({ ...point, sequence }));
  const m = routeMetrics(all);
  transaction(db, () => {
    const insert = db.prepare('INSERT INTO route_points (route_id, sequence, lat, lon, elevation, recorded_at) VALUES (?, ?, ?, ?, ?, ?)');
    for (let i = 0; i < parsed.points.length; i += 1) {
      const p = parsed.points[i]; insert.run(id, current.length + i, p.lat, p.lon, p.elevation, p.recordedAt);
    }
    db.prepare(`UPDATE routes SET start_lat=?, start_lon=?, center_lat=?, center_lon=?, min_lat=?, min_lon=?, max_lat=?, max_lon=?, distance_m=?, elevation_gain_m=?, point_count=?, updated_at=CURRENT_TIMESTAMP WHERE id=?`)
      .run(m.startLat, m.startLon, m.centerLat, m.centerLon, m.minLat, m.minLon, m.maxLat, m.maxLon, m.distanceM, m.elevationGainM, m.pointCount, id);
  });
  removeUpload(gpxFile);
  return getRoute(db, id);
}

export function listPois(db, routeId) {
  const pois = db.prepare('SELECT * FROM pois WHERE route_id = ? ORDER BY sequence, id').all(routeId);
  const imageStatement = db.prepare('SELECT id, path, caption, sequence FROM poi_images WHERE poi_id = ? ORDER BY sequence, id');
  return pois.map(poi => ({
    id: poi.id, routeId: poi.route_id, title: poi.title, description: poi.description,
    lat: poi.lat, lon: poi.lon, triggerRadiusM: poi.trigger_radius_m, sequence: poi.sequence,
    audioUrl: poi.audio_path ? audioUrl(poi.route_id, poi.id) : null,
    images: imageStatement.all(poi.id).map(image => ({
      id: image.id,
      caption: image.caption,
      sequence: image.sequence,
      url: pictureUrl(poi.route_id, poi.id, image.id)
    }))
  }));
}

export function getPoi(db, routeId, poiId) {
  const row = db.prepare(`SELECT p.id FROM pois p JOIN routes r ON r.id = p.route_id
    WHERE p.id = ? AND p.route_id = ? AND r.status = 'active'`).get(poiId, routeId);
  if (!row) throw new HttpError(404, 'POI nicht gefunden.');
  return listPois(db, routeId).find(poi => poi.id === Number(poiId));
}

export function createPoi(db, routeId, fields) {
  const route = db.prepare("SELECT id FROM routes WHERE id = ? AND status = 'active'").get(routeId);
  if (!route) throw new HttpError(404, 'Strecke nicht gefunden.');
  const lat = Number.parseFloat(fields.lat);
  const lon = Number.parseFloat(fields.lon);
  if (!Number.isFinite(lat) || !Number.isFinite(lon)) {
    throw new HttpError(400, 'Gültige POI-Koordinaten sind erforderlich.');
  }
  const result = db.prepare(`INSERT INTO pois (route_id, title, description, lat, lon, trigger_radius_m, sequence) VALUES (?, ?, ?, ?, ?, ?, ?)`)
    .run(routeId, fields.title || 'Unbenannter POI', fields.description || '', lat, lon,
      Number.parseFloat(fields.triggerRadiusM || config.defaultPoiTriggerMeters), Number.parseInt(fields.sequence || '0', 10));
  return listPois(db, routeId).find(poi => poi.id === Number(result.lastInsertRowid));
}

export function updatePoi(db, routeId, poiId, fields) {
  const existing = db.prepare(`SELECT p.*, r.status FROM pois p JOIN routes r ON r.id = p.route_id
    WHERE p.id = ? AND p.route_id = ?`).get(poiId, routeId);
  if (!existing || existing.status !== 'active') throw new HttpError(404, 'POI nicht gefunden.');
  const lat = fields.lat == null ? existing.lat : Number.parseFloat(fields.lat);
  const lon = fields.lon == null ? existing.lon : Number.parseFloat(fields.lon);
  const radius = fields.triggerRadiusM == null ? existing.trigger_radius_m : Number.parseFloat(fields.triggerRadiusM);
  const sequence = fields.sequence == null ? existing.sequence : Number.parseInt(fields.sequence, 10);
  if (![lat, lon, radius].every(Number.isFinite) || !Number.isInteger(sequence) || sequence < 0) {
    throw new HttpError(400, 'POI-Koordinaten, Auslöseradius oder Reihenfolge sind ungültig.');
  }
  db.prepare(`UPDATE pois SET title=?, description=?, lat=?, lon=?, trigger_radius_m=?, sequence=?, updated_at=CURRENT_TIMESTAMP WHERE id=?`)
    .run(fields.title ?? existing.title, fields.description ?? existing.description, lat, lon, radius, sequence, poiId);
  return listPois(db, existing.route_id).find(poi => poi.id === Number(poiId));
}

export function softDeleteRoute(db, id) {
  const route = db.prepare("SELECT * FROM routes WHERE id = ? AND status = 'active'").get(id);
  if (!route) throw new HttpError(404, 'Aktive Strecke nicht gefunden.');
  const moved = softDeleteRouteDirectory(id);
  try {
    transaction(db, () => {
      db.prepare(`UPDATE routes SET status='deleted', deleted_at=CURRENT_TIMESTAMP, trash_path=?, gpx_path=REPLACE(gpx_path, ?, ?), updated_at=CURRENT_TIMESTAMP WHERE id=?`)
        .run(moved.targetPrefix, moved.sourcePrefix, moved.targetPrefix, id);
      db.prepare('UPDATE pois SET audio_path = REPLACE(audio_path, ?, ?) WHERE route_id = ? AND audio_path IS NOT NULL').run(moved.sourcePrefix, moved.targetPrefix, id);
      db.prepare(`UPDATE poi_images SET path = REPLACE(path, ?, ?) WHERE poi_id IN (SELECT id FROM pois WHERE route_id = ?)`)
        .run(moved.sourcePrefix, moved.targetPrefix, id);
    });
  } catch (error) {
    fs.renameSync(moved.destination, routeDirectory(id));
    throw error;
  }
  return rowToRoute(db.prepare('SELECT * FROM routes WHERE id = ?').get(id), true);
}

export function restoreRoute(db, id) {
  const route = db.prepare("SELECT * FROM routes WHERE id = ? AND status = 'deleted'").get(id);
  if (!route) throw new HttpError(404, 'Gelöschte Strecke nicht gefunden.');
  const moved = restoreRouteDirectory(id, route.trash_path);
  try {
    transaction(db, () => {
      db.prepare(`UPDATE routes SET status='active', deleted_at=NULL, trash_path=NULL, gpx_path=REPLACE(gpx_path, ?, ?), updated_at=CURRENT_TIMESTAMP WHERE id=?`)
        .run(moved.sourcePrefix, moved.targetPrefix, id);
      db.prepare('UPDATE pois SET audio_path = REPLACE(audio_path, ?, ?) WHERE route_id = ? AND audio_path IS NOT NULL').run(moved.sourcePrefix, moved.targetPrefix, id);
      db.prepare(`UPDATE poi_images SET path = REPLACE(path, ?, ?) WHERE poi_id IN (SELECT id FROM pois WHERE route_id = ?)`)
        .run(moved.sourcePrefix, moved.targetPrefix, id);
    });
  } catch (error) {
    fs.renameSync(moved.destination, moved.source);
    throw error;
  }
  return getRoute(db, id);
}