import {
  Body,
  Controller,
  ForbiddenException,
  Get,
  HttpCode,
  HttpStatus,
  Post,
  Req,
  Res,
  UseGuards,
} from '@nestjs/common';
import { ApiBearerAuth, ApiOperation, ApiTags } from '@nestjs/swagger';
import type { Request, Response } from 'express';
import { AdminGuard } from '../../../common/guards/admin.guard';
import { Roles } from '../../../common/decorators/roles.decorator';
import { ZodValidationPipe } from '../../../common/pipes/zod-validation.pipe';
import { ApiError } from '../../../common/errors/api-error';
import { ERROR_CODES } from '../../../common/errors/error-codes';
import { BackupService } from './backup.service';
import { RestoreService } from './restore.service';
import { DangerZoneService } from './danger-zone.service';
import { ConfirmationTokenService } from './confirmation-token.service';
import { AuthService } from '../../auth/auth.service';
import {
  AdminReauthBodySchema,
  AdminDangerConfirmBodySchema,
  AdminRestoreCommitBodySchema,
  AdminOperationKind,
} from './dto/admin-system.dto';

interface AuthedRequest extends Request {
  user?: { sub: string; role?: string };
}

function requireAdminUserId(req: AuthedRequest): string {
  if (!req.user || req.user.role !== 'admin' || !req.user.sub) {
    throw new ForbiddenException('Admin role required');
  }
  return req.user.sub;
}

@ApiTags('admin')
@ApiBearerAuth()
@Controller('api/v1/admin/system')
@UseGuards(AdminGuard)
@Roles('admin')
export class AdminSystemController {
  constructor(
    private readonly backup: BackupService,
    private readonly restore: RestoreService,
    private readonly danger: DangerZoneService,
    private readonly tokens: ConfirmationTokenService,
    private readonly auth: AuthService,
  ) {}

  @Get('backup')
  @ApiOperation({ summary: 'Download a complete database + uploads backup (admin only).' })
  async downloadBackup(@Res() res: Response): Promise<void> {
    const doc = await this.backup.build();
    const text = BackupService.stringify(doc);
    res
      .status(HttpStatus.OK)
      .setHeader('Content-Type', 'application/json; charset=utf-8')
      .setHeader(
        'Content-Disposition',
        `attachment; filename="hipctf-backup-${new Date().toISOString().replace(/[:.]/g, '-')}.json"`,
      )
      .send(text);
  }

  @Post('restore/validate')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Validate an uploaded backup document without mutating data.' })
  async validateRestore(
    @Req() req: AuthedRequest,
    @Body() body: { archive?: unknown; text?: string },
  ): Promise<unknown> {
    const userId = requireAdminUserId(req);
    let rawText: string;
    if (typeof body.text === 'string') {
      rawText = body.text;
    } else if (body.archive && typeof body.archive === 'object') {
      rawText = JSON.stringify(body.archive);
    } else {
      throw new ApiError(
        ERROR_CODES.SYSTEM_PAYLOAD_INVALID,
        'No archive provided. Send { text: "<json-string>" } or { archive: { ... } }.',
        400,
      );
    }
    return this.restore.stageArchive(rawText, userId);
  }

  @Post('restore/commit')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Commit a previously-staged restore (requires confirmation token).' })
  async commitRestore(
    @Req() req: AuthedRequest,
    @Body(new ZodValidationPipe(AdminRestoreCommitBodySchema))
    body: { operation: AdminOperationKind; token: string; stagingId?: string },
  ): Promise<{ ok: true; operation: AdminOperationKind }> {
    const userId = requireAdminUserId(req);
    if (body.operation !== 'restore-backup') {
      throw new ApiError(
        ERROR_CODES.SYSTEM_TOKEN_MISMATCH,
        'Staging id is not bound to this operation',
        400,
      );
    }
    if (!body.stagingId) {
      throw new ApiError(
        ERROR_CODES.SYSTEM_RESTORE_STAGE_EXPIRED,
        'Restore stage missing or expired',
        400,
      );
    }
    await this.tokens.consume({
      userId,
      operation: 'restore-backup',
      token: body.token,
      stagingId: body.stagingId,
    });
    const result = await this.restore.commitRestore(body.stagingId);
    void result;
    await this.auth.revokeAllRefreshSessions(userId);
    return { ok: true, operation: 'restore-backup' };
  }

  @Post('confirmations')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Reauthenticate and issue a single-use confirmation token for a destructive operation.' })
  async issueConfirmation(
    @Req() req: AuthedRequest,
    @Body(new ZodValidationPipe(AdminReauthBodySchema))
    body: { operation: AdminOperationKind; password: string; stagingId?: string },
  ): Promise<{ operation: AdminOperationKind; token: string; expiresAt: string }> {
    const userId = requireAdminUserId(req);
    const verified = await this.auth.reauthenticateAdmin(userId, body.password);
    const issued = await this.tokens.issue({ userId: verified.id, operation: body.operation });
    void body.stagingId;
    return { operation: body.operation, token: issued.token, expiresAt: issued.expiresAt };
  }

  @Post('scores/reset')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Reset all scores (delete every solve and award). Requires confirmation token.' })
  async resetScores(
    @Req() req: AuthedRequest,
    @Body(new ZodValidationPipe(AdminDangerConfirmBodySchema))
    body: { operation: AdminOperationKind; token: string },
  ): Promise<{ ok: true; solvesRemoved: number }> {
    const userId = requireAdminUserId(req);
    if (body.operation !== 'reset-scores') {
      throw new ApiError(
        ERROR_CODES.SYSTEM_TOKEN_MISMATCH,
        'Token was not issued for reset-scores',
        400,
      );
    }
    await this.tokens.consume({ userId, operation: 'reset-scores', token: body.token });
    const result = await this.danger.resetScores();
    return { ok: true, solvesRemoved: result.solvesRemoved };
  }

  @Post('challenges/wipe')
  @HttpCode(HttpStatus.OK)
  @ApiOperation({ summary: 'Wipe every challenge, cascading files and solves. Requires confirmation token.' })
  async wipeChallenges(
    @Req() req: AuthedRequest,
    @Body(new ZodValidationPipe(AdminDangerConfirmBodySchema))
    body: { operation: AdminOperationKind; token: string },
  ): Promise<{
    ok: true;
    challengesRemoved: number;
    challengeFilesRemoved: number;
    solvesRemoved: number;
  }> {
    const userId = requireAdminUserId(req);
    if (body.operation !== 'wipe-challenges') {
      throw new ApiError(
        ERROR_CODES.SYSTEM_TOKEN_MISMATCH,
        'Token was not issued for wipe-challenges',
        400,
      );
    }
    await this.tokens.consume({ userId, operation: 'wipe-challenges', token: body.token });
    const result = await this.danger.wipeChallenges();
    return { ok: true, ...result };
  }
}