import {
  Body,
  Controller,
  Delete,
  ForbiddenException,
  Get,
  HttpCode,
  HttpStatus,
  type MessageEvent,
  NotFoundException,
  Param,
  ParseIntPipe,
  Patch,
  Post,
  Query,
  Sse,
  UseGuards,
} from '@nestjs/common';
import { Session, type UserSession } from '@thallesp/nestjs-better-auth';
import { map, type Observable } from 'rxjs';
import { CreateCommentUseCase } from '../../application/use-cases/create-comment/create-comment.use-case.js';
import { ListCommentsUseCase } from '../../application/use-cases/list-comments/list-comments.use-case.js';
import { UpdateCommentUseCase } from '../../application/use-cases/update-comment/update-comment.use-case.js';
import { DeleteCommentUseCase } from '../../application/use-cases/delete-comment/delete-comment.use-case.js';
import { WatchIssueCommentsUseCase } from '../../application/use-cases/watch-issue-comments/watch-issue-comments.use-case.js';
import { CreateCommentCommand } from '../../application/use-cases/create-comment/create-comment.command.js';
import { ListCommentsQuery } from '../../application/use-cases/list-comments/list-comments.query.js';
import { UpdateCommentCommand } from '../../application/use-cases/update-comment/update-comment.command.js';
import { DeleteCommentCommand } from '../../application/use-cases/delete-comment/delete-comment.command.js';
import { WatchIssueCommentsQuery } from '../../application/use-cases/watch-issue-comments/watch-issue-comments.query.js';
import { CreateCommentRequestDto } from '../dto/create-comment.dto.js';
import { UpdateCommentRequestDto } from '../dto/update-comment.dto.js';
import { ListCommentsDto } from '../dto/list-comments.dto.js';
import { CommentNotFoundException } from '../../domain/exceptions/comment-not-found.exception.js';
import { CommentForbiddenException } from '../../domain/exceptions/comment-forbidden.exception.js';
import { IssueNotFoundException } from '../../../issue/domain/exceptions/issue-not-found.exception.js';
import { IssueVisibleGuard } from '../guards/issue-visible.guard.js';

@Controller()
export class CommentController {
  constructor(
    private readonly createCommentUseCase: CreateCommentUseCase,
    private readonly listCommentsUseCase: ListCommentsUseCase,
    private readonly updateCommentUseCase: UpdateCommentUseCase,
    private readonly deleteCommentUseCase: DeleteCommentUseCase,
    private readonly watchIssueCommentsUseCase: WatchIssueCommentsUseCase,
  ) {}

  @Get('issues/:issueId/comments')
  list(@Param('issueId', ParseIntPipe) issueId: number, @Query() query: ListCommentsDto, @Session() session: UserSession) {
    return this.handleErrors(() =>
      this.listCommentsUseCase.execute(new ListCommentsQuery(issueId, session.user.id, Number(query.limit), query.cursor)),
    );
  }

  @Post('issues/:issueId/comments')
  create(@Param('issueId', ParseIntPipe) issueId: number, @Body() dto: CreateCommentRequestDto, @Session() session: UserSession) {
    return this.handleErrors(() => this.createCommentUseCase.execute(new CreateCommentCommand(issueId, session.user.id, dto.content)));
  }

  /**
   * SSE-поток комментариев одной задачи: клиент открывает его на странице
   * задачи и закрывает при уходе. После переподключения клиенту стоит
   * перезапросить список — события, пришедшие во время обрыва, не повторяются.
   * Доступ проверяет IssueVisibleGuard — так клиент без доступа получает 404.
   */
  @Sse('issues/:issueId/comments/events')
  @UseGuards(IssueVisibleGuard)
  events(@Param('issueId', ParseIntPipe) issueId: number, @Session() session: UserSession): Promise<Observable<MessageEvent>> {
    return this.handleErrors(async () => {
      const events$ = await this.watchIssueCommentsUseCase.execute(new WatchIssueCommentsQuery(issueId, session.user.id));
      return events$.pipe(map((event) => ({ type: event.type, data: event.comment })));
    });
  }

  @Patch('comments/:id')
  update(@Param('id') id: string, @Body() dto: UpdateCommentRequestDto, @Session() session: UserSession) {
    return this.handleErrors(() => this.updateCommentUseCase.execute(new UpdateCommentCommand(id, session.user.id, dto.content)));
  }

  @Delete('comments/:id')
  @HttpCode(HttpStatus.NO_CONTENT)
  async delete(@Param('id') id: string, @Session() session: UserSession) {
    await this.handleErrors(() => this.deleteCommentUseCase.execute(new DeleteCommentCommand(id, session.user.id)));
  }

  /** Транслирует доменные исключения в HTTP-ответ — это забота presentation-слоя */
  private async handleErrors<T>(fn: () => Promise<T>): Promise<T> {
    try {
      return await fn();
    } catch (error) {
      if (error instanceof CommentNotFoundException || error instanceof IssueNotFoundException) {
        throw new NotFoundException(error.message);
      }
      if (error instanceof CommentForbiddenException) {
        throw new ForbiddenException(error.message);
      }
      throw error;
    }
  }
}