/**
 * Component: Admin API Token Management Routes
 * Documentation: documentation/backend/services/api-tokens.md
 */

import { NextRequest, NextResponse } from 'next/server';
import { requireAuth, requireAdmin, AuthenticatedRequest } from '@/lib/middleware/auth';
import { prisma } from '@/lib/db';
import { RMABLogger } from '@/lib/utils/logger';
import { checkApiTokenCreateRateLimit } from '@/lib/utils/rateLimit';
import { MAX_TOKENS_PER_USER } from '@/lib/constants/api-tokens';
import { generateApiToken } from '@/lib/utils/api-token';
import { z } from 'zod';

const logger = RMABLogger.create('API.Admin.ApiTokens');

const CreateTokenSchema = z.object({
  name: z.string().min(1).max(100),
  expiresAt: z.string().datetime().nullable().optional(),
  userId: z.string().uuid().optional(), // Admin can specify which user the token acts as
  role: z.enum(['admin', 'user']).optional(), // Accepted for compatibility, but cannot differ from target user role
});

/**
 * GET /api/admin/api-tokens
 * List ALL API tokens across all users
 */
export async function GET(request: NextRequest) {
  return requireAuth(request, (req: AuthenticatedRequest) =>
    requireAdmin(req, async () => {
      try {
        const tokens = await prisma.apiToken.findMany({
          include: {
            createdBy: {
              select: { id: true, plexUsername: true },
            },
            tokenUser: {
              select: { id: true, plexUsername: true, role: true },
            },
          },
          orderBy: { createdAt: 'desc' },
        });

        const sanitized = tokens.map((t) => ({
          id: t.id,
          name: t.name,
          tokenPrefix: t.tokenPrefix,
          role: t.role,
          createdBy: t.createdBy.plexUsername,
          createdById: t.createdBy.id,
          tokenUser: t.tokenUser.plexUsername,
          tokenUserId: t.tokenUser.id,
          lastUsedAt: t.lastUsedAt,
          expiresAt: t.expiresAt,
          createdAt: t.createdAt,
        }));

        return NextResponse.json({ tokens: sanitized });
      } catch (error) {
        logger.error('Failed to list API tokens', { error: error instanceof Error ? error.message : String(error) });
        return NextResponse.json({ error: 'Failed to list API tokens' }, { status: 500 });
      }
    })
  );
}

/**
 * POST /api/admin/api-tokens
 * Create a new API token. Admin can optionally specify userId.
 * Token role is always derived from the target user's current role.
 * Returns the full token ONCE.
 */
export async function POST(request: NextRequest) {
  return requireAuth(request, (req: AuthenticatedRequest) =>
    requireAdmin(req, async () => {
      try {
        const rateLimit = checkApiTokenCreateRateLimit(req.user!.id);
        if (!rateLimit.allowed) {
          return NextResponse.json(
            { error: 'Too many API token create attempts. Please try again later.' },
            {
              status: 429,
              headers: {
                'Retry-After': String(rateLimit.retryAfterSeconds),
              },
            }
          );
        }

        const body = await req.json();
        const { name, expiresAt, userId, role } = CreateTokenSchema.parse(body);

        // Determine target user (defaults to the admin themselves)
        const targetUserId = userId || req.user!.id;

        // Verify the target user exists
        const targetUser = await prisma.user.findUnique({
          where: { id: targetUserId },
          select: { id: true, role: true, plexUsername: true },
        });

        if (!targetUser) {
          return NextResponse.json({ error: 'Target user not found' }, { status: 404 });
        }

        // Enforce per-user token cap (count only active, non-expired tokens)
        const activeTokenCount = await prisma.apiToken.count({
          where: {
            userId: targetUserId,
            OR: [
              { expiresAt: null },
              { expiresAt: { gt: new Date() } },
            ],
          },
        });

        if (activeTokenCount >= MAX_TOKENS_PER_USER) {
          return NextResponse.json(
            { error: `Token limit reached. Users may have at most ${MAX_TOKENS_PER_USER} active API tokens.` },
            { status: 403 }
          );
        }

        // Security guard: token role must always match the target user's persisted role.
        // This avoids role/identity mismatch (for example: acting as user A with admin role).
        if (role && role !== targetUser.role) {
          logger.warn('Admin attempted token role override that differs from target user role', {
            requestedRole: role,
            userActualRole: targetUser.role,
            targetUser: targetUser.plexUsername,
            createdBy: req.user!.username,
          });

          return NextResponse.json(
            {
              error: `Token role must match target user's role (${targetUser.role}).`,
            },
            { status: 400 }
          );
        }

        const tokenRole = targetUser.role;

        // Generate the token
        const { fullToken, tokenHash, tokenPrefix } = generateApiToken();

        const apiToken = await prisma.apiToken.create({
          data: {
            name,
            tokenHash,
            tokenPrefix,
            role: tokenRole,
            createdById: req.user!.id,
            userId: targetUserId,
            expiresAt: expiresAt ? new Date(expiresAt) : null,
          },
        });

        logger.info('Admin API token created', {
          tokenId: apiToken.id,
          name,
          createdBy: req.user!.username,
          targetUser: targetUser.plexUsername,
          role: tokenRole,
        });

        return NextResponse.json({
          token: {
            id: apiToken.id,
            name: apiToken.name,
            tokenPrefix: apiToken.tokenPrefix,
            role: apiToken.role,
            expiresAt: apiToken.expiresAt,
            createdAt: apiToken.createdAt,
          },
          // Full token is returned ONLY on creation
          fullToken,
        }, { status: 201 });
      } catch (error) {
        logger.error('Failed to create API token', { error: error instanceof Error ? error.message : String(error) });

        if (error instanceof z.ZodError) {
          return NextResponse.json({ error: 'Validation error', details: error.errors }, { status: 400 });
        }

        return NextResponse.json({ error: 'Failed to create API token' }, { status: 500 });
      }
    })
  );
}