import {
  Body,
  Controller,
  Delete,
  Get,
  GoneException,
  HttpCode,
  Param,
  Patch,
  Post,
  Put,
  Req,
  Res,
} from '@nestjs/common';
import {
  CollabTokenResponse,
  CreatePageInput,
  PageListItemView,
  PageStateView,
  PageView,
  RepositionPageInput,
  UpdatePageInput,
  createPageInputSchema,
  repositionPageInputSchema,
  updatePageInputSchema,
} from '@dorfteich/shared';
import type { Response } from 'express';

import { AuthedRequest, Public } from '../auth/auth.guard';
import { ZodValidationPipe } from '../common/zod-validation.pipe';
import {
  AuthenticatedOnly,
  RequiresPagePermission,
  RequiresPondRole,
} from '../permissions/permission.decorators';
import { PagesService } from './pages.service';

/** Page CRUD and Yjs state persistence (issue #23; permission guard since #52). */
@Controller()
export class PagesController {
  constructor(private readonly pages: PagesService) {}

  @Post('ponds/:pondId/pages')
  @RequiresPondRole('editor', { idParam: 'pondId' })
  async create(
    @Param('pondId') pondId: string,
    @Body(new ZodValidationPipe(createPageInputSchema)) input: CreatePageInput,
    @Req() request: AuthedRequest,
  ): Promise<PageView> {
    return this.pages.create(request.user!, pondId, input);
  }

  @Get('ponds/:pondId/pages')
  @RequiresPondRole('reader', { idParam: 'pondId' }) // the service filters per page
  async list(
    @Param('pondId') pondId: string,
    @Req() request: AuthedRequest,
  ): Promise<PageListItemView[]> {
    return this.pages.list(request.user!, pondId);
  }

  @Get('pages/:id')
  @RequiresPagePermission('read', { idParam: 'id' })
  async getState(@Param('id') id: string, @Req() request: AuthedRequest): Promise<PageStateView> {
    return this.pages.getState(request.user!, id);
  }

  /**
   * Short-lived collaboration token for the collab server (issue #34).
   * `@Public()` so an anonymous visitor to a public page can obtain a token
   * (issue #53); the permission guard still enforces read access (404 when no
   * grant makes the page readable) and downgrades non-writers to `ro`.
   */
  @Get('pages/:id/collab-token')
  @Public()
  @RequiresPagePermission('read', { idParam: 'id' }) // readers (incl. public) get an `ro` token
  async collabToken(
    @Param('id') id: string,
    @Req() request: AuthedRequest,
  ): Promise<CollabTokenResponse> {
    return this.pages.issueCollabToken(request.user ?? null, id);
  }

  /** Markdown export (issue #30) — downloads `<slug>.md`. */
  @Get('pages/:id/export/markdown')
  @RequiresPagePermission('read', { idParam: 'id' })
  async exportMarkdown(
    @Param('id') id: string,
    @Req() request: AuthedRequest,
    @Res({ passthrough: true }) response: Response,
  ): Promise<string> {
    const { slug, markdown } = await this.pages.exportMarkdown(request.user!, id);
    response.set('Content-Type', 'text/markdown; charset=utf-8');
    response.set('Content-Disposition', `attachment; filename="${slug}.md"`);
    return markdown;
  }

  /** Resolves the pond-slug + page-slug pair the `/p/:pondSlug/:pageSlug` route
   * navigates to (issue #25); the pond id must already be known to the caller
   * (e.g. from `GET /ponds/:slug`). */
  @Get('ponds/:pondId/pages/:slug')
  @RequiresPagePermission('read', { pondIdParam: 'pondId', slugParam: 'slug' })
  async getStateBySlug(
    @Param('pondId') pondId: string,
    @Param('slug') slug: string,
    @Req() request: AuthedRequest,
  ): Promise<PageStateView> {
    return this.pages.getStateBySlug(request.user!, pondId, slug);
  }

  /**
   * The REST state-write path was retired when the editor moved to live
   * collaboration (#36): document changes now flow through the collab server
   * (ADR 0003), which is the sole writer of page state. The read paths (`GET`)
   * remain. Kept as an explicit 410 so any stale client gets a clear signal.
   */
  @Put('pages/:id/state')
  @AuthenticatedOnly() // always 410 — never touches the page
  saveState(): never {
    throw new GoneException({
      code: 'rest_state_write_retired',
      details: { hint: 'Page content is edited live over the collaboration server (/collab).' },
    });
  }

  /** Reposition a page in the manual sidebar order (issue #45). */
  @Patch('pages/:id/position')
  @RequiresPagePermission('write', { idParam: 'id' })
  async reposition(
    @Param('id') id: string,
    @Body(new ZodValidationPipe(repositionPageInputSchema)) input: RepositionPageInput,
    @Req() request: AuthedRequest,
  ): Promise<PageView> {
    return this.pages.reposition(request.user!, id, input);
  }

  @Patch('pages/:id')
  @RequiresPagePermission('write', { idParam: 'id' })
  async update(
    @Param('id') id: string,
    @Body(new ZodValidationPipe(updatePageInputSchema)) input: UpdatePageInput,
    @Req() request: AuthedRequest,
  ): Promise<PageView> {
    return this.pages.update(request.user!, id, input);
  }

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