import express from 'express';
import cors from 'cors';
import { Low } from 'lowdb';
import { JSONFile } from 'lowdb/node';
import { join, dirname } from 'path';
import { fileURLToPath } from 'url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const dataDir = join(__dirname, 'data');
import { mkdirSync } from 'fs';
mkdirSync(dataDir, { recursive: true });
const dbFile = join(dataDir, 'db.json');
const adapter = new JSONFile(dbFile);
const defaultData = { members: [], projects: [], tasks: [] };
const db = new Low(adapter, defaultData);

await db.read();
await db.write();

const app = express();
app.use(cors());
app.use(express.json());

// Member CRUD
app.get('/api/members', (req, res) => {
  res.json(db.data.members);
});

app.post('/api/members', (req, res) => {
  const member = { id: Date.now().toString(), ...req.body };
  db.data.members.push(member);
  db.write();
  res.status(201).json(member);
});

app.delete('/api/members/:id', (req, res) => {
  db.data.members = db.data.members.filter(m => m.id !== req.params.id);
  db.write();
  res.status(204).end();
});

app.put('/api/members/:id', async (req, res) => {
  const idx = db.data.members.findIndex(m => m.id === req.params.id);
  if (idx === -1) return res.status(404).json({ error: 'Member not found' });
  db.data.members[idx] = { ...db.data.members[idx], ...req.body, id: req.params.id };
  await db.write();
  res.json(db.data.members[idx]);
});

// Project CRUD
app.get('/api/projects', (req, res) => {
  res.json(db.data.projects);
});

app.post('/api/projects', (req, res) => {
  const project = { id: Date.now().toString(), members: [], ...req.body };
  db.data.projects.push(project);
  db.write();
  res.status(201).json(project);
});

app.put('/api/projects/:id', async (req, res) => {
  const idx = db.data.projects.findIndex(p => p.id === req.params.id);
  const updated = { ...req.body, id: req.params.id };
  if (idx === -1) db.data.projects.push(updated);
  else db.data.projects[idx] = updated;
  await db.write();
  res.json(updated);
});

app.delete('/api/projects/:id', (req, res) => {
  db.data.projects = db.data.projects.filter(p => p.id !== req.params.id);
  db.write();
  res.status(204).end();
});

// Assign member to project
app.post('/api/projects/:projectId/members/:memberId', (req, res) => {
  const project = db.data.projects.find(p => p.id === req.params.projectId);
  if (!project) return res.status(404).json({ error: 'Project not found' });
  if (!project.members.includes(req.params.memberId)) {
    project.members.push(req.params.memberId);
    db.write();
  }
  res.json(project);
});

// Tasks (assign to member in project)
app.post('/api/projects/:projectId/tasks', (req, res) => {
  const { title, description, memberId } = req.body;
  const project = db.data.projects.find(p => p.id === req.params.projectId);
  if (!project) return res.status(404).json({ error: 'Project not found' });
  if (!project.members.includes(memberId)) return res.status(400).json({ error: 'Member not assigned to project' });
  const task = { id: Date.now().toString(), projectId: project.id, memberId, title, description, status: 'todo' };
  db.data.tasks.push(task);
  db.write();
  res.status(201).json(task);
});

app.get('/api/projects/:projectId/tasks', (req, res) => {
  const tasks = db.data.tasks.filter(t => t.projectId === req.params.projectId);
  res.json(tasks);
});

const PORT = process.env.PORT || 4000;
app.listen(PORT, () => console.log(`Backend running on port ${PORT}`));