import { readFileSync, existsSync, mkdirSync, writeFileSync } from "node:fs";
import { join } from "node:path";
import { spawn, spawnSync } from "node:child_process";

// ── Config ───────────────────────────────────────────────────────────────────
// Project config: ralph.config.json at repo root. Missing → auto-detect (vite).
// Fields: kind, port, url, routes[], serveStart, smokeBuild, smokeStart, env{}, ttlSeconds.

const DEFAULT_PORT = 4173;

function readJSON(p) {
	try {
		return JSON.parse(readFileSync(p, "utf-8"));
	} catch {
		return null;
	}
}

function depHas(pkg, name) {
	return !!(pkg?.dependencies?.[name] || pkg?.devDependencies?.[name]);
}

function autoDetect(root) {
	const pkg = readJSON(join(root, "package.json")) ?? {};
	const scripts = pkg.scripts ?? {};
	const port = DEFAULT_PORT;
	const url = `http://localhost:${port}`;
	const isVite = depHas(pkg, "vite") || depHas(pkg, "@sveltejs/kit") || !!scripts.preview;
	if (isVite) {
		return {
			kind: "web",
			port,
			url,
			routes: ["/"],
			// serve (exploration): dev server gives source errors + HMR; WE supervise+reap it.
			serveStart: scripts.dev ? `npm run dev -- --port ${port} --strictPort` : `npx vite dev --port ${port} --strictPort`,
			// smoke (deterministic): production build + preview.
			smokeBuild: scripts.build ? "npm run build" : "npx vite build",
			smokeStart: `npx vite preview --port ${port} --strictPort`,
			env: {},
			ttlSeconds: 1800,
		};
	}
	// generic node server fallback
	return {
		kind: scripts.start ? "server" : "cli",
		port,
		url,
		routes: ["/"],
		serveStart: scripts.start ? "npm start" : "",
		smokeBuild: scripts.build ? "npm run build" : "",
		smokeStart: scripts.start ? "npm start" : "",
		env: {},
		ttlSeconds: 1800,
	};
}

export function loadConfig(root) {
	const declared = readJSON(join(root, "ralph.config.json"));
	const auto = autoDetect(root);
	const cfg = { ...auto, ...(declared ?? {}) };
	cfg.url = cfg.url ?? `http://localhost:${cfg.port}`;
	cfg.routes = cfg.routes ?? ["/"];
	cfg.env = cfg.env ?? {};
	return cfg;
}

// ── Paths ────────────────────────────────────────────────────────────────────

export function ralphDir(root) {
	const d = join(root, ".ralph");
	if (!existsSync(d)) mkdirSync(d, { recursive: true });
	return d;
}
export const pidPath = (root) => join(ralphDir(root), "serve.pid");
export const logPath = (root) => join(ralphDir(root), "serve.log");

// ── Port hygiene ─────────────────────────────────────────────────────────────

export function killPort(port) {
	// try fuser, then lsof — best-effort, never throws
	spawnSync("bash", ["-c", `fuser -k ${port}/tcp 2>/dev/null; true`], { timeout: 8000 });
	spawnSync("bash", ["-c", `lsof -ti tcp:${port} 2>/dev/null | xargs -r kill -9 2>/dev/null; true`], { timeout: 8000 });
}

// ── Process helpers ──────────────────────────────────────────────────────────

// Spawn a server in its OWN process group (detached:true calls setsid() for the
// child → child.pid == pgid), so we can kill the whole tree with kill(-pid)
// without ever signalling our own group. Returns the child (group leader).
export function spawnServer(startCmd, cwd, env, logFd) {
	return spawn("bash", ["-c", startCmd], {
		cwd,
		env: { ...process.env, ...env, CI: "1", NO_COLOR: "1", FORCE_COLOR: "0", BROWSER: "none" },
		stdio: ["ignore", logFd, logFd],
		detached: true,
	});
}

export function killGroup(pid, signal = "SIGTERM") {
	if (!pid || pid === process.pid || pid === process.ppid) return; // never signal ourselves
	try {
		process.kill(-pid, signal); // negative pid = the child's own process group
	} catch {
		try {
			process.kill(pid, signal);
		} catch {
			/* already dead */
		}
	}
}

export function pidAlive(pid) {
	try {
		process.kill(pid, 0);
		return true;
	} catch {
		return false;
	}
}

// ── wait-on (bounded, no dep) ────────────────────────────────────────────────

export async function waitOn(url, timeoutMs = 60000, intervalMs = 500) {
	const deadline = Date.now() + timeoutMs;
	while (Date.now() < deadline) {
		try {
			const res = await fetch(url, { method: "GET", redirect: "manual", headers: { Connection: "close" } });
			if (res.status > 0) return true; // any HTTP response = server is up
		} catch {
			/* not up yet */
		}
		await sleep(intervalMs);
	}
	return false;
}

export const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

// ── HTTP probe ───────────────────────────────────────────────────────────────

export async function httpProbe(baseUrl, routes, expectStatus = 200) {
	const rows = [];
	for (const route of routes) {
		const url = baseUrl.replace(/\/$/, "") + route;
		const t0 = Date.now();
		try {
			const res = await fetch(url, { redirect: "manual", headers: { Connection: "close" } });
			const ms = Date.now() - t0;
			const ctype = res.headers.get("content-type") ?? "";
			const body = await res.text();
			const expected = typeof expectStatus === "object" ? (expectStatus[route] ?? 200) : expectStatus;
			const redirect = res.status >= 300 && res.status < 400 ? res.headers.get("location") : null;
			rows.push({
				route,
				status: res.status,
				ms,
				ctype: ctype.split(";")[0],
				bytes: Buffer.byteLength(body),
				redirect,
				ok: res.status === expected,
				snippet: res.status < 200 || res.status >= 300 ? body.replace(/\s+/g, " ").trim().slice(0, 200) : "",
			});
		} catch (e) {
			rows.push({ route, status: 0, ms: Date.now() - t0, error: String(e.message), ok: false });
		}
	}
	return rows;
}

// ── Browser probe (Playwright chromium, headless) ────────────────────────────
// Degrades gracefully to a note if playwright isn't installed.

export async function browserProbe(baseUrl, route, actions = []) {
	let chromium;
	try {
		({ chromium } = await import("playwright"));
	} catch {
		return {
			available: false,
			note: "browser probe skipped — playwright not installed. Run: cd ~/Sources/ralph-runtime && npm i playwright && npx playwright install chromium",
			consoleErrors: [],
			consoleMessages: [],
			ok: true, // don't fail the smoke just because the browser probe is unavailable
		};
	}
	const errors = [];       // pageerror + console.error — drives the verdict
	const messages = [];     // EVERY console.* message (log/info/warn/error/debug), in order
	let browser;
	try {
		browser = await chromium.launch({ headless: true });
		const page = await browser.newPage();
		page.on("pageerror", (e) => {
			const t = String(e.message || e);
			errors.push(t);
			messages.push({ type: "pageerror", text: t });
		});
		page.on("console", (m) => {
			const type = m.type();
			const text = m.text();
			messages.push({ type, text });
			if (type === "error") errors.push(text);
		});
		const url = baseUrl.replace(/\/$/, "") + route;
		await page.goto(url, { waitUntil: "networkidle", timeout: 30000 });
		for (const a of actions) {
			try {
				const [verb, ...rest] = a.split(/\s+/);
				if (verb === "click" && rest.length >= 2) {
					await page.mouse.click(Number(rest[0]), Number(rest[1]));
				} else if (verb === "clickText") {
					await page.getByText(rest.join(" ")).first().click({ timeout: 5000 });
				} else if (verb === "wait") {
					await sleep(Number(rest[0]) || 500);
				}
				await sleep(300);
			} catch (e) {
				errors.push(`action "${a}" failed: ${String(e.message)}`);
			}
		}
		await sleep(400); // let async errors surface
		return { available: true, consoleErrors: errors, consoleMessages: messages, ok: errors.length === 0 };
	} catch (e) {
		const t = `navigation failed: ${String(e.message)}`;
		return { available: true, consoleErrors: [...errors, t], consoleMessages: [...messages, { type: "pageerror", text: t }], ok: false };
	} finally {
		if (browser) await browser.close().catch(() => {});
	}
}

// ── misc ─────────────────────────────────────────────────────────────────────

export function tailFile(p, n = 40) {
	try {
		const lines = readFileSync(p, "utf-8").split("\n");
		return lines.slice(-n).join("\n");
	} catch {
		return "";
	}
}

export function writePid(root, pid, ttlSeconds) {
	writeFileSync(pidPath(root), JSON.stringify({ pid, startedAt: Date.now(), ttlSeconds }));
}
export function readPid(root) {
	return readJSON(pidPath(root));
}
export function clearPid(root) {
	try {
		writeFileSync(pidPath(root), "");
	} catch {
		/* ignore */
	}
}