import Fastify from 'fastify'
import fastifyStatic from '@fastify/static'
import { readFile, writeFile, mkdir } from 'fs/promises'
import { join, dirname } from 'path'
import { fileURLToPath } from 'url'
import { existsSync } from 'fs'

const __dirname = dirname(fileURLToPath(import.meta.url))
const ROOT = join(__dirname, '..')
const DIST = join(ROOT, 'dist')
const SAVES_DIR = join(ROOT, 'data', 'saves')

// Ensure saves directory exists
await mkdir(SAVES_DIR, { recursive: true })

const fastify = Fastify({ logger: false })

// Serve built frontend
await fastify.register(fastifyStatic, {
  root: DIST,
  prefix: '/',
})

// Load save state
fastify.get('/api/save/:token', async (req, reply) => {
  const { token } = req.params
  if (!/^[0-9a-f]{8}$/.test(token)) {
    return reply.code(400).send({ error: 'Invalid token' })
  }
  const path = join(SAVES_DIR, `${token}.json`)
  if (!existsSync(path)) {
    return reply.code(404).send({ error: 'Save not found' })
  }
  try {
    const raw = await readFile(path, 'utf8')
    return reply.send(JSON.parse(raw))
  } catch {
    return reply.code(500).send({ error: 'Failed to read save' })
  }
})

// Write save state
fastify.post('/api/save/:token', async (req, reply) => {
  const { token } = req.params
  if (!/^[0-9a-f]{8}$/.test(token)) {
    return reply.code(400).send({ error: 'Invalid token' })
  }
  if (!req.body || typeof req.body !== 'object') {
    return reply.code(400).send({ error: 'Invalid body' })
  }
  const path = join(SAVES_DIR, `${token}.json`)
  try {
    await writeFile(path, JSON.stringify(req.body, null, 2), 'utf8')
    return reply.send({ ok: true })
  } catch {
    return reply.code(500).send({ error: 'Failed to write save' })
  }
})

// Fallback — serve index.html for client-side routing
fastify.setNotFoundHandler((req, reply) => {
  reply.sendFile('index.html')
})

try {
  await fastify.listen({ port: 3000, host: '0.0.0.0' })
  console.log('OTIVM server running on port 3000')
} catch (err) {
  console.error(err)
  process.exit(1)
}