import type { User } from '../../types';
import { RuntimeEnvService } from '../app-config/runtime-env.service';
import { logInfo } from '../audit/audit-log.logger';
import { AuditService } from '../audit/audit.service';
import { getClientIp } from '../audit/client-ip';
import { CurrentUser } from '../auth-core/current-user.decorator';
import { JwtAuthGuard } from '../auth-core/jwt-auth.guard';
import { CalendarService } from '../calendar/calendar.service';
import { contentDisposition } from '../common/content-disposition';
import { isDemoWriteBlocked, DEMO_WRITE_ERROR } from '../common/demo-write';
import { StorageReleaseService } from '../storage/storage-release.service';
import { StorageService } from '../storage/storage.service';
import { TripReadModelService } from '../trip-read-model/trip-read-model.service';
import { UnsplashService } from '../unsplash/unsplash.service';
import { TripWritesService } from './trip-writes.service';
import {
  TripCreateDto,
  TripUpdateDto,
  TripCopyDto,
  TripAddMemberDto,
  TripTransferOwnershipDto,
  TripCreateGuestDto,
  TripRenameGuestDto,
} from './trips.dto';
import { tripUpdatePermissions } from './trips.helpers';
import { TripsService } from './trips.service';
import { NotFoundError, ValidationError } from './trips.service';
import {
  Body,
  Controller,
  Delete,
  Get,
  Headers,
  HttpCode,
  HttpException,
  Param,
  Post,
  Put,
  Query,
  Req,
  Res,
  UploadedFile,
  UseGuards,
  UseInterceptors,
} from '@nestjs/common';
import { FileInterceptor } from '@nestjs/platform-express';
import { MAX_TRIP_DAYS, type ActiveTripResponse, type TripSearchResponse } from '@trek/shared';

import type { Request, Response } from 'express';
import type { Options } from 'multer';
import path from 'path';

export const MAX_COVER_SIZE = 20 * 1024 * 1024;
// Still needed by the Unsplash cover download (a raw-fs writer until the
// caches/downloads slice); the multer destination moved to the storage spool.
// Consumed by trips.module.ts's MulterModule factory. Quirk preserved on
// purpose: a plain Error without statusCode maps to 500, not 400 (parity).
export const TRIP_COVER_FILE_FILTER: Options['fileFilter'] = (_req, file, cb) => {
  const ext = path.extname(file.originalname).toLowerCase();
  const allowed = ['.jpg', '.jpeg', '.png', '.gif', '.webp'];
  if (file.mimetype.startsWith('image/') && !file.mimetype.includes('svg') && allowed.includes(ext)) cb(null, true);
  else cb(new Error('Only jpg, png, gif, webp images allowed'));
};

/**
 * /api/trips — the trip aggregate root.
 *
 * Byte-identical to the legacy Express route (server/src/routes/trips.ts): the
 * same per-field permission checks (trip_create / trip_edit / trip_archive /
 * trip_cover_upload / trip_delete / member_manage), the date inference on create,
 * audit logging, the offline bundle, ICS export and member-invite notification.
 * Uses EXACT strangler prefixes so it never swallows the nested sub-domain mounts.
 */
@Controller('api/trips')
@UseGuards(JwtAuthGuard)
export class TripsController {
  // calendar last: the hand-wired construction sites in the tests stay positional,
  // so a new dependency does not touch the ones that never reach the ICS route.
  constructor(
    private readonly trips: TripsService,
    private readonly audit: AuditService,
    private readonly env: RuntimeEnvService,
    private readonly unsplash: UnsplashService,
    private readonly calendar: CalendarService,
    private readonly readModel: TripReadModelService,
    private readonly storage: StorageService,
    private readonly tripWrites: TripWritesService,
    private readonly release: StorageReleaseService,
  ) {}

  @Get()
  async list(@CurrentUser() user: User, @Query('archived') archived?: string) {
    return { trips: await this.trips.list(user.id, archived === '1' ? 1 : 0) };
  }

  /**
   * Where "open TREK straight in my trip" lands. Declared above @Get(':id') —
   * a literal segment below it would never be reached.
   */
  @Get('active')
  async active(@CurrentUser() user: User): Promise<ActiveTripResponse> {
    const row = await this.trips.activeTrip(user.id);
    if (!row) return { trip: null };
    const { id, title, start_date, end_date } = row;
    return { trip: { id, title, start_date, end_date } };
  }

  /** Places across the user's trips for the dashboard search (#2190). Above @Get(':id'). */
  @Get('search')
  async search(@CurrentUser() user: User, @Query('q') q?: string): Promise<TripSearchResponse> {
    return { matches: await this.trips.searchPlaces(user.id, typeof q === 'string' ? q.slice(0, 100) : '') };
  }

  @Get('cover-images/search')
  async coverImages(@CurrentUser() user: User, @Query('query') query?: string) {
    try {
      const result = await this.trips.searchCoverImages(query || '', user.id);
      return { photos: result.photos };
    } catch (err: unknown) {
      if (err instanceof HttpException) throw err;
      console.error('Unsplash cover image error:', err);
      throw new HttpException({ error: 'Error searching for cover images' }, 500);
    }
  }

  @Post()
  @HttpCode(201)
  async create(
    @CurrentUser() user: User,
    @Body() body: TripCreateDto,
    @Req() req: Request,
    @Headers('x-socket-id') socketId?: string,
  ) {
    if (!(await this.trips.can('trip_create', user.role, null, user.id, false))) {
      throw new HttpException({ error: 'No permission to create trips' }, 403);
    }
    // Presence/shape validation happens in the ZodValidationPipe (tripCreateRequestSchema).
    const { title, description, currency, reminder_days, day_count } = body;
    const start_date: string | null = body.start_date || null;
    const end_date: string | null = body.end_date || null;
    if (start_date && end_date && new Date(end_date) < new Date(start_date)) {
      throw new HttpException({ error: 'End date must be after start date' }, 400);
    }
    const parsedDayCount = day_count ? Math.min(Math.max(Number(day_count) || 7, 1), MAX_TRIP_DAYS) : undefined;
    try {
      const { trip, tripId, reminderDays } = await this.tripWrites.create(
        { title, description, start_date, end_date, currency, reminder_days, day_count: parsedDayCount },
        { userId: user.id, role: user.role, socketId },
      );
      await this.audit.writeAudit({
        userId: user.id,
        action: 'trip.create',
        ip: getClientIp(req),
        details: { tripId, title, reminder_days: reminderDays === 0 ? 'none' : `${reminderDays} days` },
      });
      if (reminderDays > 0) logInfo(`${user.email} set ${reminderDays}-day reminder for trip "${title}"`);
      return { trip };
    } catch (e: unknown) {
      if (e instanceof ValidationError) throw new HttpException({ error: e.message }, 400);
      throw e;
    }
  }

  @Get(':id')
  async get(@CurrentUser() user: User, @Param('id') id: string) {
    const trip = await this.trips.get(id, user.id);
    if (!trip) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    return { trip };
  }

  @Put(':id')
  async update(
    @CurrentUser() user: User,
    @Param('id') id: string,
    @Body() body: TripUpdateDto,
    @Req() req: Request,
    @Headers('x-socket-id') socketId?: string,
  ) {
    const access = await this.trips.canAccessTrip(id, user.id);
    if (!access) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    const ownerId = access.user_id;
    const isMember = ownerId !== user.id;
    // A body the caller may only partly write is refused on the first right it lacks, in the list's order.
    const needed = tripUpdatePermissions(body);
    const granted = await Promise.all(
      needed.map(({ action }) => this.trips.can(action, user.role, ownerId, user.id, isMember)),
    );
    const lacking = needed.find((_, i) => !granted[i]);
    if (lacking) throw new HttpException({ error: lacking.refusal }, 403);
    // A chosen Unsplash cover arrives as an images.unsplash.com hot-link; download
    // it into uploads/covers so the cover survives offline + CDN link-rot (#1277).
    if (this.unsplash.isUnsplashCoverUrl(body.cover_image)) {
      try {
        const filename = await this.unsplash.saveUnsplashCover(body.cover_image);
        body.cover_image = `/uploads/covers/${filename}`;
      } catch (e) {
        console.error('Unsplash cover download failed:', e);
        throw new HttpException({ error: 'Could not save the selected cover image' }, 502);
      }
    }
    try {
      const result = await this.trips.update(id, user.id, body, user.role);
      if (Object.keys(result.changes).length > 0) {
        await this.audit.writeAudit({
          userId: user.id,
          action: 'trip.update',
          ip: getClientIp(req),
          details: {
            tripId: Number(id),
            trip: result.newTitle,
            ...(result.ownerEmail ? { owner: result.ownerEmail } : {}),
            ...result.changes,
          },
        });
        if (result.isAdminEdit && result.ownerEmail)
          logInfo(`Admin ${user.email} edited trip "${result.newTitle}" owned by ${result.ownerEmail}`);
      }
      if (result.newReminder !== result.oldReminder) {
        if (result.newReminder > 0)
          logInfo(`${user.email} set ${result.newReminder}-day reminder for trip "${result.newTitle}"`);
        else logInfo(`${user.email} removed reminder for trip "${result.newTitle}"`);
      }
      this.trips.broadcast(id, 'trip:updated', { trip: result.updatedTrip }, socketId);
      return { trip: result.updatedTrip };
    } catch (e: unknown) {
      if (e instanceof NotFoundError) throw new HttpException({ error: e.message }, 404);
      if (e instanceof ValidationError) throw new HttpException({ error: e.message }, 400);
      throw e;
    }
  }

  @Post(':id/cover')
  @UseInterceptors(FileInterceptor('cover'))
  async cover(
    @CurrentUser() user: User,
    @Param('id') id: string,
    @UploadedFile() file: Express.Multer.File | undefined,
  ) {
    if (isDemoWriteBlocked(this.env, user.email)) {
      throw new HttpException(DEMO_WRITE_ERROR, 403);
    }
    const access = await this.trips.canAccessTrip(id, user.id);
    if (!access?.user_id) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    if (!(await this.trips.can('trip_cover_upload', user.role, access.user_id, user.id, access.user_id !== user.id))) {
      throw new HttpException({ error: 'No permission to change the cover image' }, 403);
    }
    const trip = (await this.trips.getRaw(id)) as { cover_image: string | null } | undefined;
    if (!trip) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    if (!file) {
      throw new HttpException({ error: 'No image uploaded' }, 400);
    }
    // Commit the spooled upload to its final storage location (atomic
    // same-volume rename) before anything references the final path.
    await this.storage.put('covers', file.filename, { tmpPath: file.path });
    const coverUrl = `/uploads/covers/${file.filename}`;
    await this.trips.updateCoverImage(id, coverUrl);
    // The replaced cover goes unless a trip copy or a journey still shows it.
    await this.release.releaseValues([trip.cover_image]);
    return { cover_image: coverUrl };
  }

  @Post(':id/copy')
  @HttpCode(201)
  async copy(
    @CurrentUser() user: User,
    @Param('id') id: string,
    @Body() body: TripCopyDto,
    @Req() req: Request,
    @Headers('x-socket-id') socketId?: string,
  ) {
    if (!(await this.trips.can('trip_create', user.role, null, user.id, false))) {
      throw new HttpException({ error: 'No permission to create trips' }, 403);
    }
    if (!(await this.trips.canAccessTrip(id, user.id))) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    const { title } = body;
    try {
      const newTripId = await this.tripWrites.copy(id, title, { userId: user.id, role: user.role, socketId });
      await this.audit.writeAudit({
        userId: user.id,
        action: 'trip.copy',
        ip: getClientIp(req),
        details: { sourceTripId: Number(id), newTripId, title },
      });
      return { trip: await this.trips.getCopiedTrip(newTripId, user.id) };
    } catch {
      throw new HttpException({ error: 'Failed to copy trip' }, 500);
    }
  }

  @Delete(':id')
  async remove(
    @CurrentUser() user: User,
    @Param('id') id: string,
    @Req() req: Request,
    @Headers('x-socket-id') socketId?: string,
  ) {
    const owner = await this.trips.getOwner(id);
    if (!owner) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    // Someone with no access at all gets the same 404 as a trip that does not
    // exist, otherwise the 403 below turns sequential ids into an existence
    // oracle. Admins are exempt: they may delete trips they are not a member of,
    // which is what the isAdminDelete branch further down relies on.
    if (user.role !== 'admin' && !(await this.trips.canAccessTrip(id, user.id))) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    if (!(await this.trips.can('trip_delete', user.role, owner.user_id, user.id, owner.user_id !== user.id))) {
      throw new HttpException({ error: 'No permission to delete this trip' }, 403);
    }
    const info = await this.tripWrites.remove(id, this.tripWrites.restWriter(id, user, socketId));
    await this.audit.writeAudit({
      userId: user.id,
      action: 'trip.delete',
      ip: getClientIp(req),
      details: { tripId: info.tripId, trip: info.title, ...(info.ownerEmail ? { owner: info.ownerEmail } : {}) },
    });
    if (info.isAdminDelete && info.ownerEmail)
      logInfo(`Admin ${user.email} deleted trip "${info.title}" owned by ${info.ownerEmail}`);
    return { success: true };
  }

  @Get(':id/bundle')
  async bundle(@CurrentUser() user: User, @Param('id') id: string) {
    const trip = (await this.trips.get(id, user.id)) as { user_id: number } | undefined;
    if (!trip) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    return this.readModel.bundle(id, trip, user.id);
  }

  @Get(':id/export.ics')
  async exportIcs(@CurrentUser() user: User, @Param('id') id: string, @Res() res: Response) {
    if (!(await this.trips.canAccessTrip(id, user.id))) {
      throw new HttpException({ error: 'Trip not found' }, 404);
    }
    try {
      const { ics, filename } = await this.calendar.exportICS(id);
      res.setHeader('Content-Type', 'text/calendar; charset=utf-8');
      res.setHeader('Content-Disposition', contentDisposition(filename, 'attachment'));
      res.send(ics);
    } catch (e: unknown) {
      if (e instanceof NotFoundError) throw new HttpException({ error: e.message }, 404);
      throw e;
    }
  }
}