import http from 'http'
import fs from 'fs'
import path from 'path'
import { fileURLToPath } from 'url'
import Docker from 'dockerode'
import cron from 'node-cron'

const LABEL_USER_KEY = 'openwebui.user-id',
	ANNO_DISPLAY_NAME = 'openwebui/display-name'

const __filename = fileURLToPath(import.meta.url),
	__dirname = path.dirname(__filename),

	// folders/files
	DATA_DIR = process.env.DATA_DIR || path.join(__dirname, 'data'),
	SCHEDULES_FILE = path.join(DATA_DIR, 'schedules.json'),
	TEMPLATES_FILE = process.env.TEMPLATES_FILE || path.join(__dirname, 'templates.json'),

	// defaults
	DEFAULT_TZ = 'America/New_York',
	PORT = Number(process.env.PORT) || 12253

// connect to docker (via local socket by default)
const docker = new Docker({ socketPath: process.env.DOCKER_SOCKET || '/var/run/docker.sock' })

// in-memory schedule registry
const tasks = new Map() // key -> { task, def }

const readBodyJson = (req) => new Promise((resolve, reject) => {
	let d = ''; req.on('data', c => d += c)
	req.on('end', () => { try { resolve(JSON.parse(d || '{}')) } catch (e) { reject(e) } })
	req.on('error', reject)
}),
	ensureDir = (p) => { try { fs.mkdirSync(p, { recursive: true }) } catch { } },
	readJsonFile = (p, fallback = null) => { try { return JSON.parse(fs.readFileSync(p, 'utf8')) } catch { return fallback } },
	writeJsonFile = (p, obj) => fs.writeFileSync(p, JSON.stringify(obj, null, 2))

// build cron string from an iso timestamp in a timezone (same as your original)
const cronFromISO = (iso, tz = DEFAULT_TZ) => {
	const dt = new Date(iso),
		parts = new Intl.DateTimeFormat('en-US', {
			timeZone: tz, year: 'numeric', month: 'numeric', day: 'numeric',
			hour: 'numeric', minute: '2-digit', hour12: false
		}).formatToParts(dt).reduce((a, p) => (a[p.type] = p.value, a), {})
	const m = Number(parts.month), d = Number(parts.day), h = Number(parts.hour), min = Number(parts.minute)
	return `${min} ${h} ${d} ${m} *`
}

// derive a docker-safe, user-scoped name and preserve a human display name
const scopedName = (name, userId) => {
	const base = String(name).toLowerCase().replace(/[^a-z0-9-]+/g, '-').replace(/^-+|-+$/g, '').slice(0, 40),
		suffix = String(userId).toLowerCase().replace(/[^a-z0-9]+/g, '').slice(0, 8) || 'anon'
	return `${base}--u-${suffix}`
}

// ensure we have a user id header
const requireUserId = (req) => {
	const userId = String(req.headers['x-user-id'] || '').trim()
	if (!userId) throw Object.assign(new Error('missing x-user-id header'), { status: 401 })
	return userId
}

// load templates (maps "name" -> { image, command?, args?, env? })
const loadTemplates = () => readJsonFile(TEMPLATES_FILE, { items: [] }).items || []
const findTemplate = (name) => loadTemplates().find(t => t.name === name)

// create/start a container for a template (run once)
async function runContainer({ displayName, template, parameters = {}, userId, entrypoint }) {
	if (!template?.name) throw Object.assign(new Error('missing template.name'), { status: 400 })
	const t = findTemplate(template.name)
	if (!t) throw Object.assign(new Error(`unknown template: ${template.name}`), { status: 404 })

	// env: pass user + params as env vars (simple & portable)
	const env = [
		`USER_ID=${userId}`,
		`DISPLAY_NAME=${displayName}`,
		...Object.entries(parameters).map(([k, v]) => `PARAM_${String(k).toUpperCase()}=${String(v)}`)
	]

	// image pull if absent then create+start (mirrors docker run flow)
	// ref: docker engine api sequence: create -> pull if 404 -> create -> start
	// https://docs.docker.com/reference/api/engine/version/v1.24/ (section 4.1)
	try {
		await docker.getImage(t.image).inspect()
	} catch {
		await new Promise((resolve, reject) => {
			docker.pull(t.image, (err, stream) => {
				if (err) return reject(err)
				docker.modem.followProgress(stream, (err2) => err2 ? reject(err2) : resolve())
			})
		})
	}

	const nameActual = `${scopedName(displayName || t.name, userId)}-${Math.random().toString(36).slice(2, 8)}`

	// build container create options
	const createOpts = {
		Image: t.image,
		// optional explicit entrypoint/cmd wiring
		Entrypoint: entrypoint ? [entrypoint] : (t.entrypoint ? [].concat(t.entrypoint) : undefined),
		Cmd: t.command ? [].concat(t.command, t.args || []) : (t.args ? [].concat(t.args) : undefined),
		Env: env,
		Labels: {
			[LABEL_USER_KEY]: userId,
			[ANNO_DISPLAY_NAME]: displayName || t.name
		},
		HostConfig: {
			AutoRemove: true
		},
		name: nameActual
	}

	const container = await docker.createContainer(createOpts) // create
	await container.start() // start
	return { id: container.id, name: nameActual }
}

// persistence of schedules (for restart durability)
ensureDir(DATA_DIR)
const persist = () => {
	const defs = [...tasks.values()].map(v => v.def)
	writeJsonFile(SCHEDULES_FILE, { items: defs })
}
const restore = () => {
	const saved = readJsonFile(SCHEDULES_FILE, { items: [] }).items || []
	for (const def of saved) scheduleOrReplace(def)
}

// schedule management (create/update)
function scheduleOrReplace(def) {
	// stop existing
	const key = def.name
	if (tasks.has(key)) { try { tasks.get(key).task.stop() } catch { } tasks.delete(key) }

	// forbid overlapping runs per schedule (like argo's Forbid)
	let running = false
	const task = cron.schedule(def.schedule, async () => {
		if (running) return
		running = true
		try {
			await runContainer({
				displayName: def.displayName,
				template: def.template,
				parameters: def.parameters,
				userId: def.userId,
				entrypoint: def.entrypoint
			})
			// one-shot: stop after first success
			if (def.oneShot) {
				try { task.stop() } catch { }
				tasks.delete(key)
				persist()
			}
		} catch (e) {
			// you could log or collect errors here
		} finally {
			running = false
		}
	}, { timezone: def.timezone || DEFAULT_TZ })

	tasks.set(key, { task, def })
	task.start()
	persist()
}

// convert input to schedule def
const toScheduleDef = ({ name, when, tz = DEFAULT_TZ, oneShot = false, template = { name: '' }, parameters = {}, entrypoint, userId }) => {
	const schedule = when?.cron ?? cronFromISO(when?.iso, tz)
	return {
		name: scopedName(name, userId),
		displayName: name,
		userId,
		timezone: tz,
		schedule,
		oneShot: Boolean(oneShot),
		template,
		parameters,
		entrypoint
	}
}

const publicDir = path.join(__dirname, 'public');

function reqToURL(req) {
	let pathname = '/';
	try {
		pathname = new URL(req.url, `http://${req.headers.host || 'localhost'}`).pathname;
	} catch {
		pathname = req.url || '/';
	}

	return pathname;
}

// http server
const server = http.createServer(async (req, res) => {
	try {
		// very light cors
		const origin = req.headers.origin || '*'
		res.setHeader('access-control-allow-origin', origin)
		res.setHeader('vary', 'origin')
		res.setHeader('access-control-allow-headers', 'content-type, x-user-id')
		res.setHeader('access-control-allow-methods', 'GET, POST, DELETE, OPTIONS')
		if (req.method === 'OPTIONS') return res.writeHead(204).end()

		const pathname = reqToURL(req),
			allowed = ['/', '/index.html', '/script.js', '/style.css'];


		//#region GET requests

		// list schedules for the calling user
		if (req.method === 'GET' && pathname === '/api/schedules') {
			const userId = requireUserId(req),
				items = [...tasks.values()]
					.map(v => v.def)
					.filter(d => d.userId === userId)
					.map(d => ({
						name: d.name,
						displayName: d.displayName,
						userId: d.userId,
						timezone: d.timezone,
						schedules: [d.schedule],
						oneShot: d.oneShot,
						templateRef: d.template,
						entrypoint: d.entrypoint
					}));

			return res.writeHead(200, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: true, items }))
		}

		// list "workflow templates" => just expose templates.json names
		if (req.method === 'GET' && pathname === '/api/workflowtemplates') {
			const items = loadTemplates().map(t => ({ name: t.name }))
			return res.writeHead(200, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: true, items }))
		}

		if (req.method === 'GET' && allowed.includes(pathname)) {
			try {
				const fileName = pathname === '/' ? 'index.html' : pathname.slice(1),
					filePath = path.join(publicDir, fileName),
					ext = path.extname(fileName).toLowerCase(),
					type = ext === '.js' ? 'application/javascript' : ext === '.css' ? 'text/css' : 'text/html; charset=utf-8',
					content = fs.readFileSync(filePath, 'utf8')
				return res.writeHead(200, { 'content-type': type }).end(content);
			} catch {
				return res.writeHead(404).end('ui not found');
			}

		}

		// DO NOT PUT ANY GET REQUESTS BELOW THIS LINE, THEY WILL FAIL

		//#endregion

		// create/update a user-scoped schedule
		if (req.method === 'POST' && pathname === '/schedules') {
			const userId = requireUserId(req),
				input = await readBodyJson(req),
				def = toScheduleDef({ ...input, userId })
			scheduleOrReplace(def)
			return res.writeHead(201, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: true }))
		}

		// run a job now for the calling user (no schedule)
		if (req.method === 'POST' && pathname === '/run-now') {
			const userId = requireUserId(req),
				input = await readBodyJson(req)
			await runContainer({
				displayName: input.name,
				template: input.template,
				parameters: input.parameters || {},
				userId,
				entrypoint: input.entrypoint
			})
			return res.writeHead(201, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: true }))
		}

		// delete a schedule owned by the calling user
		if (req.method === 'DELETE' && pathname.startsWith('/schedules/')) {
			const userId = requireUserId(req),
				nameParam = decodeURIComponent(pathname.split('/').pop()),
				// stored names are already scoped; accept either raw or scoped
				key = tasks.has(nameParam) ? nameParam : scopedName(nameParam, userId),
				existing = tasks.get(key)?.def

			if (!existing) return res.writeHead(404, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: false, error: 'not found' }))
			if (existing.userId !== userId) return res.writeHead(403, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: false, error: 'forbidden: schedule not owned by this user' }))

			try { tasks.get(key).task.stop() } catch { }
			tasks.delete(key)
			persist()
			return res.writeHead(204).end()
		}

		res.writeHead(404).end('not found')
	} catch (e) {
		const code = Number(e.status) || 500
		res.writeHead(code, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: false, error: e.message || String(e) }))
	}
})

// boot
restore()
server.listen(PORT, "0.0.0.0", () => console.log(`schedules api listening on ${server.address().address}:${PORT}`));