import express from "express";
import { spawnSync } from "child_process";
import path from "path";
import { actions } from "./actions.js";
import { enqueue, getEntry, listPending, resolve } from "./queue.js";

const PORT = process.env.CONDUIT_PORT || 3015;
const WORKSPACE_ROOT = process.env.CONDUIT_ROOT || "/workspace";

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

// Resolve a path param relative to WORKSPACE_ROOT, preventing traversal.
function resolvePath(userPath) {
	const resolved = path.resolve(WORKSPACE_ROOT, userPath.replace(/^\//, ""));
	if (!resolved.startsWith(WORKSPACE_ROOT)) {
		throw new Error(`Path escapes workspace root: ${userPath}`);
	}
	return resolved;
}

// Execute a binary with an argument list — no shell interpolation.
function exec(bin, args = []) {
	return new Promise((resolve, reject) => {
		const result = spawnSync(bin, args, { stdio: "inherit" });
		if (result.error) {
			reject(result.error);
		} else {
			resolve(result.status);
		}
	});
}

const helpers = { resolvePath, exec };

// Validate that all required params are present.
function validateParams(actionDef, params) {
	const errors = [];
	for (const p of actionDef.params) {
		if (p.required && (params[p.name] === undefined || params[p.name] === null)) {
			errors.push(`Missing required param: ${p.name}`);
		}
	}
	return errors;
}

// POST /action  — main entry point
app.post("/action", async (req, res) => {
	const { action, ...params } = req.body ?? {};

	if (!action) {
		return res.status(400).json({ error: "Missing 'action' field" });
	}

	const def = actions[action];
	if (!def) {
		return res.status(404).json({ error: `Unknown action: ${action}` });
	}

	const errors = validateParams(def, params);
	if (errors.length) {
		return res.status(400).json({ error: "Invalid params", details: errors });
	}

	if (def.policy === "auto-deny") {
		return res.status(403).json({ status: "denied", reason: "Policy: auto-deny" });
	}

	if (def.policy === "auto-accept") {
		try {
			const result = await def.handler(params, helpers);
			return res.json({ status: "accepted", result });
		} catch (err) {
			return res.status(500).json({ status: "error", error: err.message });
		}
	}

	if (def.policy === "queue") {
		const id = enqueue(action, params);
		return res.status(202).json({ status: "queued", id });
	}
});

// GET /queue — list pending items
app.get("/queue", (req, res) => {
	res.json(listPending());
});

// POST /queue/:id/approve — user approves a queued action
app.post("/queue/:id/approve", async (req, res) => {
	const entry = getEntry(req.params.id);
	if (!entry) {
		return res.status(404).json({ error: "Not found" });
	}
	if (entry.status !== "pending") {
		return res.status(409).json({ error: "Already resolved" });
	}

	resolve(req.params.id, "approved");

	const def = actions[entry.action];
	try {
		const result = await def.handler(entry.params, helpers);
		res.json({ status: "approved", result });
	} catch (err) {
		res.status(500).json({ status: "error", error: err.message });
	}
});

// POST /queue/:id/deny — user denies a queued action
app.post("/queue/:id/deny", (req, res) => {
	const entry = getEntry(req.params.id);
	if (!entry) {
		return res.status(404).json({ error: "Not found" });
	}
	if (entry.status !== "pending") {
		return res.status(409).json({ error: "Already resolved" });
	}

	resolve(req.params.id, "denied");
	res.json({ status: "denied" });
});

app.listen(PORT, () => {
	console.log(`claude-code-conduit server running on port ${PORT}`);
	console.log(`Workspace root: ${WORKSPACE_ROOT}`);
});