import {
  BadRequestException,
  Controller,
  Delete,
  Get,
  HttpCode,
  Param,
  Post,
  Req,
  Res,
  StreamableFile,
  UploadedFile,
  UseInterceptors,
} from '@nestjs/common';
import { FileInterceptor } from '@nestjs/platform-express';
import {
  AttachmentListItemView,
  AttachmentView,
  MAX_UPLOAD_PARSE_BYTES,
  PondFilesView,
} from '@dorfteich/shared';
import type { Response } from 'express';

import { AuthedRequest, Public } from '../auth/auth.guard';
import {
  RequiresAttachmentPermission,
  RequiresPagePermission,
  RequiresPondRole,
} from '../permissions/permission.decorators';

import { FilesService } from './files.service';

/** File storage, upload, and attachment listing API (issue #27, #61). */
@Controller()
export class FilesController {
  constructor(private readonly files: FilesService) {}

  @Post('ponds/:pondId/files')
  @RequiresPondRole('editor', { idParam: 'pondId' })
  @UseInterceptors(FileInterceptor('file', { limits: { fileSize: MAX_UPLOAD_PARSE_BYTES } }))
  async upload(
    @Param('pondId') pondId: string,
    @UploadedFile() file: Express.Multer.File | undefined,
    @Req() request: AuthedRequest,
  ): Promise<AttachmentView> {
    if (!file) throw new BadRequestException({ code: 'bad_request' });
    return this.files.upload(request.user!, pondId, file);
  }

  /** All files in a pond, for the Pond Admin file manager (#61). */
  @Get('ponds/:pondId/files')
  @RequiresPondRole('pond_admin', { idParam: 'pondId' })
  listPondFiles(@Param('pondId') pondId: string): Promise<PondFilesView> {
    return this.files.listForPond(pondId);
  }

  /** Upload an attachment linked to a page — its attachments section (#61). */
  @Post('pages/:pageId/files')
  @RequiresPagePermission('write', { idParam: 'pageId' })
  @UseInterceptors(FileInterceptor('file', { limits: { fileSize: MAX_UPLOAD_PARSE_BYTES } }))
  async uploadToPage(
    @Param('pageId') pageId: string,
    @UploadedFile() file: Express.Multer.File | undefined,
    @Req() request: AuthedRequest,
  ): Promise<AttachmentView> {
    if (!file) throw new BadRequestException({ code: 'bad_request' });
    return this.files.uploadToPage(request.user!, pageId, file);
  }

  /** Attachments linked to a page, for its attachments section (#61). */
  @Get('pages/:pageId/files')
  @RequiresPagePermission('read', { idParam: 'pageId' })
  listPageFiles(@Param('pageId') pageId: string): Promise<AttachmentListItemView[]> {
    return this.files.listForPage(pageId);
  }

  /**
   * Permission-checked file streaming (ADR 0011) — never served same-origin as
   * executable content. `@Public()` so embedded images on a public page load
   * for anonymous visitors (issue #56); the guard still resolves the `public`
   * grant via the attachment's page and 404s otherwise. Raster images render
   * inline; every other type — office files, PDFs, SVG — is sent as a download
   * with its original filename and can never execute inline (#61).
   */
  @Get('media/:fileId')
  @Public()
  @RequiresAttachmentPermission('read', { idParam: 'fileId' })
  async download(
    @Param('fileId') fileId: string,
    @Req() request: AuthedRequest,
    @Res({ passthrough: true }) response: Response,
  ): Promise<StreamableFile> {
    const { attachment, stream, inline, downloadName } = await this.files.download(
      request.user ?? null,
      fileId,
    );
    response.set('X-Content-Type-Options', 'nosniff');
    // Attachments are immutable — a new upload always gets a new id.
    response.set('Cache-Control', 'private, max-age=31536000, immutable');
    const kind = inline ? 'inline' : 'attachment';
    return new StreamableFile(stream, {
      type: attachment.mimeType,
      disposition: `${kind}; filename="${encodeURIComponent(downloadName)}"`,
    });
  }

  @Delete('files/:id')
  @HttpCode(204)
  @RequiresAttachmentPermission('write', { idParam: 'id' })
  async remove(@Param('id') id: string, @Req() request: AuthedRequest): Promise<void> {
    await this.files.remove(request.user!, id);
  }
}