import { randomUUID } from 'node:crypto';
import {
  BadRequestException,
  Body,
  Controller,
  Get,
  Headers,
  HttpCode,
  Param,
  Post,
} from '@nestjs/common';
import { ThreadsService } from './threads.service';
import { MessageService } from '../messaging/message.service';
import { SessionVerifier } from '../platform/session.verifier';
import { SendMessageDto } from './send-message.dto';

@Controller('v1/threads')
export class ThreadsController {
  constructor(
    private readonly threads: ThreadsService,
    private readonly messages: MessageService,
    private readonly session: SessionVerifier,
  ) {}

  /** Generic "my threads" — every thread the caller participates in (last message + unread). */
  @Get()
  async listThreads(@Headers('authorization') auth?: string) {
    return this.messages.listThreads(this.principal(auth));
  }

  /** Create a thread; `membership`/`creatorRole` are opaque, app-supplied thread attributes the kernel stores but never interprets. */
  @Post()
  @HttpCode(201)
  async createThread(@Body() body: { membership?: string; creatorRole?: string }, @Headers('authorization') auth?: string) {
    return this.messages.openThread(null, this.principal(auth), { membership: body?.membership, creatorRole: body?.creatorRole });
  }

  /** Governed membership: add a user (by userId) to a thread — policy enforces DM cap / roles. */
  @Post(':id/participants')
  @HttpCode(201)
  async addParticipant(@Param('id') id: string, @Body() body: { userId: string; role?: string }, @Headers('authorization') auth?: string) {
    return this.messages.addParticipant(id, this.principal(auth), body.userId, body.role);
  }

  @Get(':id/messages')
  async listMessages(@Param('id') id: string) {
    return this.threads.getMessages(id);
  }

  /** REST/polling fallback for native send (same write as the socket path). */
  @Post(':id/messages')
  @HttpCode(201)
  async send(
    @Param('id') id: string,
    @Body() body: SendMessageDto,
    @Headers('authorization') authorization?: string,
    @Headers('idempotency-key') idempotencyKey?: string,
  ) {
    return this.messages.send(
      id,
      this.principal(authorization),
      { content: body.content, contentRef: body.contentRef },
      idempotencyKey ?? randomUUID(),
      undefined,
      body.parentInteractionId,
    );
  }

  private principal(authorization?: string) {
    const token = (authorization ?? '').replace(/^Bearer\s+/i, '');
    if (!token) throw new BadRequestException('Authorization bearer token is required');
    return this.session.verify(token);
  }
}