import http from 'http'
import fs from 'fs'
import path from 'path'
import { fileURLToPath } from 'url'
import { KubeConfig, CustomObjectsApi } from '@kubernetes/client-node'

const GROUP = 'argoproj.io',
	VERSION = 'v1alpha1',
	CRON_PLURAL = 'cronworkflows',
	WF_PLURAL = 'workflows',
	NAMESPACE = process.env.NS || 'argo',

	// k8s label/annotation keys (must be lowercase dns-labels)
	LABEL_USER_KEY = 'openwebui.user-id',
	ANNO_DISPLAY_NAME = 'openwebui/display-name';

// load cluster credentials
const kc = new KubeConfig();
try { kc.loadFromCluster() } catch { kc.loadFromDefault() }

const co = kc.makeApiClient(CustomObjectsApi);

// build cron string from an iso timestamp in a tz
const cronFromISO = (iso, tz = 'America/New_York') => {
	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), {}),

		m = Number(parts.month), d = Number(parts.day), h = Number(parts.hour), min = Number(parts.minute);

	return `${min} ${h} ${d} ${m} *`;
}

// derive a k8s-safe, user-scoped name and preserve a human display name
const scopedName = (name, userId) => {
	// keep to dns-1123 by trimming/normalizing a bit; add an 8-char user suffix for uniqueness
	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;
}

// normalize parameters and force-inject user_id
const buildParams = (parameters = {}, userId) => {
	const merged = { ...parameters, user_id: userId },
		args = Object.entries(merged).map(([name, value]) => ({ name, value }));
	return args.length ? { parameters: args } : undefined;
}

// create or update a cronworkflow that runs a workflowtemplate (scoped to user)
async function upsertCronWorkflow({
	name, when, tz = 'America/New_York', oneShot = false,
	template = { name: '', clusterScope: false },
	parameters = {}, entrypoint, userId
}) {
	const schedule = when.cron ?? cronFromISO(when.iso, tz),
		nameActual = scopedName(name, userId),

		body = {
			apiVersion: `${GROUP}/${VERSION}`,
			kind: 'CronWorkflow',
			metadata: {
				name: nameActual,
				labels: { [LABEL_USER_KEY]: userId },
				annotations: { [ANNO_DISPLAY_NAME]: name },
			},
			spec: {
				timezone: tz,
				schedules: [schedule],
				concurrencyPolicy: 'Forbid',
				...(oneShot ? { stopStrategy: { expression: 'cronworkflow.succeeded >= 1' } } : {}),
				workflowSpec: {
					...(entrypoint ? { entrypoint } : {}),
					arguments: buildParams(parameters, userId),
					workflowTemplateRef: {
						name: template.name,
						...(template.clusterScope ? { clusterScope: true } : {})
					}
				}
			}
		};

	// try patch, else create
	try {
		await co.patchNamespacedCustomObject(
			GROUP, VERSION, NAMESPACE, CRON_PLURAL, nameActual, body,
			undefined, undefined, undefined,
			{ headers: { 'content-type': 'application/merge-patch+json' } }
		);
	} catch {
		await co.createNamespacedCustomObject(GROUP, VERSION, NAMESPACE, CRON_PLURAL, body);
	}
}

// run immediately (no schedule) by creating a workflow from the same template (scoped to user)
async function runNow({ name, template, parameters = {}, entrypoint, userId }) {
	const wf = {
		apiVersion: `${GROUP}/${VERSION}`,
		kind: 'Workflow',
		metadata: {
			generateName: `${scopedName(name, userId)}-`,
			labels: { [LABEL_USER_KEY]: userId },
			annotations: { [ANNO_DISPLAY_NAME]: name },
		},
		spec: {
			...(entrypoint ? { entrypoint } : {}),
			arguments: buildParams(parameters, userId),
			workflowTemplateRef: {
				name: template.name,
				...(template.clusterScope ? { clusterScope: true } : {})
			}
		}
	};

	await co.createNamespacedCustomObject(GROUP, VERSION, NAMESPACE, WF_PLURAL, wf);
}

const __filename = fileURLToPath(import.meta.url),
	__dirname = path.dirname(__filename),
	publicDir = path.join(__dirname, 'public');

// tiny json helper
const readJson = (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);
});

const server = http.createServer(async (req, res) => {
	try {
		// death
		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()

		// minimal static ui
		if (req.method === 'GET' && (req.url === '/' || req.url === '/index.html')) {
			try {
				const html = fs.readFileSync(path.join(publicDir, 'index.html'), 'utf8');
				res.writeHead(200, { 'content-type': 'text/html; charset=utf-8' }).end(html);
			} catch {
				res.writeHead(404).end('ui not found');
			}
			return;
		}

		// list CronWorkflows for the calling user
		if (req.method === 'GET' && req.url === '/api/schedules') {
			const userId = requireUserId(req),
				list = await co.listNamespacedCustomObject(
					GROUP, VERSION, NAMESPACE, CRON_PLURAL,
					undefined, undefined, undefined, `${LABEL_USER_KEY}=${userId}` // labelSelector
				),
				items = (list.body.items || []).map(it => ({
					name: it.metadata?.name,
					displayName: it.metadata?.annotations?.[ANNO_DISPLAY_NAME] || it.metadata?.name,
					userId: it.metadata?.labels?.[LABEL_USER_KEY],
					timezone: it.spec?.timezone,
					schedules: it.spec?.schedules,
					oneShot: Boolean(it.spec?.stopStrategy),
					templateRef: it.spec?.workflowSpec?.workflowTemplateRef,
					entrypoint: it.spec?.workflowSpec?.entrypoint,
				}));

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

		// list WorkflowTemplates for UI (shared)
		if (req.method === 'GET' && req.url === '/api/workflowtemplates') {
			const list = await co.listNamespacedCustomObject(GROUP, VERSION, NAMESPACE, 'workflowtemplates'),
				items = (list.body.items || []).map(it => ({ name: it.metadata?.name }));

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

		// create/update a user-scoped schedule
		if (req.method === 'POST' && req.url === '/schedules') {
			const userId = requireUserId(req),
				input = await readJson(req);

			await upsertCronWorkflow({ ...input, userId });
			return res.writeHead(201, { 'content-type': 'application/json' }).end(JSON.stringify({ ok: true }));
		}

		// run a job now for the calling user
		if (req.method === 'POST' && req.url === '/run-now') {
			const userId = requireUserId(req),
				input = await readJson(req);

			await runNow({ ...input, userId });
			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' && req.url?.startsWith('/schedules/')) {
			const userId = requireUserId(req),
				name = decodeURIComponent(req.url.split('/').pop());

			// guard: verify ownership via label before deletion
			const obj = await co.getNamespacedCustomObject(GROUP, VERSION, NAMESPACE, CRON_PLURAL, name),
				owner = obj.body?.metadata?.labels?.[LABEL_USER_KEY];

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

			await co.deleteNamespacedCustomObject(GROUP, VERSION, NAMESPACE, CRON_PLURAL, name);
			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) }));
	}
});

const port = Number(process.env.PORT) || 12253;
server.listen(port, () => console.log(`schedules api listening on :${port}`));