import { Router } from 'express';
import { prisma } from '../lib/prisma';
import { authMiddleware } from '../lib/auth';

const router = Router();

const str = (v: string | string[] | undefined): string =>
  Array.isArray(v) ? (v[0] ?? '') : (v ?? '');

async function getUserRole(
  userId: string,
  globalRole: string,
  projectId: string
): Promise<string | null> {
  if (globalRole === 'ADMIN') return 'ADMIN';
  const project = await prisma.project.findUnique({
    where: { id: projectId },
    select: { ownerId: true, members: { where: { userId }, select: { role: true } } },
  });
  if (!project) return null;
  if (project.ownerId === userId) return 'OWNER';
  return project.members[0]?.role ?? null;
}

function canManage(role: string | null): boolean {
  return role === 'ADMIN' || role === 'EDITOR' || role === 'OWNER';
}

// ── CORS preflight ────────────────────────────────────────────────────────────
router.options('/', (_req, res) => { res.set('Access-Control-Allow-Origin', '*'); res.sendStatus(200); });
router.options('/:id', (_req, res) => { res.set('Access-Control-Allow-Origin', '*'); res.sendStatus(200); });

// ── GET /api/folders/project/:projectId ───────────────────────────────────────
router.get('/project/:projectId', authMiddleware, async (req, res) => {
  try {
    const projectId = str(req.params.projectId);
    const role = await getUserRole(req.user!.userId, req.user!.globalRole, projectId);
    if (!role) { res.status(403).json({ error: 'Forbidden' }); return; }

    const folders = await prisma.folder.findMany({
      where: { projectId },
      orderBy: [{ order: 'asc' }, { name: 'asc' }],
      include: { _count: { select: { assets: true } } },
    });

    interface FolderNode { id: string; name: string; parentId: string | null; order: number; assetCount: number; assetIds: string[]; children: FolderNode[]; }
    interface FolderWithAssets extends FolderNode { _assetIds?: string[] }

    const foldersWithAssets: FolderNode[] = await Promise.all(
      folders.map(async (f) => {
        const fa = await prisma.folderAsset.findMany({ where: { folderId: f.id }, select: { assetId: true } });
        return { id: f.id, name: f.name, parentId: f.parentId, order: f.order, assetCount: f._count.assets, assetIds: fa.map(a => a.assetId), children: [] };
      })
    );

    const map = new Map<string, FolderNode>();
    for (const f of foldersWithAssets) map.set(f.id, f);
    const roots: FolderNode[] = [];
    for (const f of foldersWithAssets) {
      if (f.parentId && map.has(f.parentId)) {
        map.get(f.parentId)!.children.push(map.get(f.id)!);
      } else {
        roots.push(map.get(f.id)!);
      }
    }

    res.json({ folders: roots, allFolders: foldersWithAssets });
  } catch (err) {
    console.error('[folders] GET /project/:projectId error:', err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// ── POST /api/folders ─────────────────────────────────────────────────────────
router.post('/', authMiddleware, async (req, res) => {
  try {
    const { name, projectId, parentId } = req.body as { name?: string; projectId?: string; parentId?: string };
    if (!name?.trim() || !projectId) { res.status(400).json({ error: 'name and projectId are required' }); return; }

    const role = await getUserRole(req.user!.userId, req.user!.globalRole, projectId);
    if (!canManage(role)) { res.status(403).json({ error: 'Forbidden' }); return; }

    if (parentId) {
      const parent = await prisma.folder.findUnique({ where: { id: parentId } });
      if (!parent || parent.projectId !== projectId) { res.status(400).json({ error: 'Invalid parent folder' }); return; }
    }

    const siblings = await prisma.folder.findMany({
      where: { projectId, parentId: parentId ?? null },
      select: { order: true }, orderBy: { order: 'desc' }, take: 1,
    });
    const nextOrder = (siblings[0]?.order ?? -1) + 1;

    const created = await prisma.folder.create({
      data: { name: name.trim(), projectId, parentId: parentId ?? null, order: nextOrder },
      include: { _count: { select: { assets: true } } },
    });

    res.status(201).json({
      folder: { id: created.id, name: created.name, parentId: created.parentId, order: created.order, assetCount: created._count.assets, assetIds: [], children: [] },
    });
  } catch (err) {
    console.error('[folders] POST / error:', err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// ── PUT /api/folders/:id ──────────────────────────────────────────────────────
router.put('/:id', authMiddleware, async (req, res) => {
  try {
    const id = str(req.params.id);
    const { name } = req.body as { name?: string };
    const existing = await prisma.folder.findUnique({ where: { id } });
    if (!existing) { res.status(404).json({ error: 'Folder not found' }); return; }
    const role = await getUserRole(req.user!.userId, req.user!.globalRole, existing.projectId);
    if (!canManage(role)) { res.status(403).json({ error: 'Forbidden' }); return; }
    const folder = await prisma.folder.update({
      where: { id },
      data: name?.trim() ? { name: name.trim() } : {},
      select: { id: true, name: true, projectId: true, parentId: true, order: true },
    });
    res.json({ folder });
  } catch (err) {
    console.error('[folders] PUT /:id error:', err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// ── DELETE /api/folders/:id ────────────────────────────────────────────────────
router.delete('/:id', authMiddleware, async (req, res) => {
  try {
    const id = str(req.params.id);
    const existing = await prisma.folder.findUnique({ where: { id } });
    if (!existing) { res.status(404).json({ error: 'Folder not found' }); return; }
    const role = await getUserRole(req.user!.userId, req.user!.globalRole, existing.projectId);
    if (!canManage(role)) { res.status(403).json({ error: 'Forbidden' }); return; }
    await prisma.folder.delete({ where: { id } });
    res.json({ success: true });
  } catch (err) {
    console.error('[folders] DELETE /:id error:', err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// ── POST /api/folders/:id/assets ───────────────────────────────────────────────
router.post('/:id/assets', authMiddleware, async (req, res) => {
  try {
    const id = str(req.params.id);
    const { assetIds } = req.body as { assetIds?: string[] };
    if (!Array.isArray(assetIds) || assetIds.length === 0) { res.status(400).json({ error: 'assetIds array is required' }); return; }

    const folder = await prisma.folder.findUnique({ where: { id } });
    if (!folder) { res.status(404).json({ error: 'Folder not found' }); return; }
    const role = await getUserRole(req.user!.userId, req.user!.globalRole, folder.projectId);
    if (!canManage(role)) { res.status(403).json({ error: 'Forbidden' }); return; }

    const validAssets = await prisma.asset.findMany({
      where: { id: { in: assetIds }, projectId: folder.projectId },
      select: { id: true },
    });
    const validIds: string[] = validAssets.map((a: { id: string }) => a.id);

    await Promise.all(
      validIds.map((assetId: string) =>
        prisma.folderAsset.upsert({
          where: { folderId_assetId: { folderId: id, assetId } },
          create: { folderId: id, assetId },
          update: {},
        })
      )
    );

    const count = await prisma.folderAsset.count({ where: { folderId: id } });
    res.json({ success: true, assetCount: count });
  } catch (err) {
    console.error('[folders] POST /:id/assets error:', err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// ── PUT /api/folders/:id/assets ───────────────────────────────────────────────
router.put('/:id/assets', authMiddleware, async (req, res) => {
  try {
    const id = str(req.params.id);
    const { assetIds } = req.body as { assetIds?: string[] };

    const folder = await prisma.folder.findUnique({ where: { id } });
    if (!folder) { res.status(404).json({ error: 'Folder not found' }); return; }
    const role = await getUserRole(req.user!.userId, req.user!.globalRole, folder.projectId);
    if (!canManage(role)) { res.status(403).json({ error: 'Forbidden' }); return; }

    const validAssets = await prisma.asset.findMany({
      where: { id: { in: assetIds ?? [] }, projectId: folder.projectId },
      select: { id: true },
    });
    const validIds: string[] = validAssets.map((a: { id: string }) => a.id);

    await prisma.folderAsset.deleteMany({ where: { folderId: id } });
    if (validIds.length > 0) {
      await prisma.folderAsset.createMany({
        data: validIds.map((assetId: string) => ({ folderId: id, assetId })),
        skipDuplicates: true,
      });
    }

    res.json({ success: true, assetCount: validIds.length });
  } catch (err) {
    console.error('[folders] PUT /:id/assets error:', err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// ── DELETE /api/folders/:id/assets/:assetId ───────────────────────────────────
router.delete('/:id/assets/:assetId', authMiddleware, async (req, res) => {
  try {
    const id = str(req.params.id);
    const assetId = str(req.params.assetId);

    const folder = await prisma.folder.findUnique({ where: { id } });
    if (!folder) { res.status(404).json({ error: 'Folder not found' }); return; }
    const role = await getUserRole(req.user!.userId, req.user!.globalRole, folder.projectId);
    if (!canManage(role)) { res.status(403).json({ error: 'Forbidden' }); return; }

    await prisma.folderAsset.deleteMany({ where: { folderId: id, assetId } });
    res.json({ success: true });
  } catch (err) {
    console.error('[folders] DELETE /:id/assets/:assetId error:', err);
    res.status(500).json({ error: 'Internal server error' });
  }
});

export default router;