import { execFileSync } from "node:child_process";
import { accessSync, constants } from "node:fs";
import { homedir } from "node:os";
import { join } from "node:path";

function isExecutable(path: string): boolean {
	try {
		accessSync(path, constants.X_OK);
		return true;
	} catch {
		return false;
	}
}

function findOnPath(name: string): string | undefined {
	try {
		const command = process.platform === "win32" ? "where" : "which";
		const output = execFileSync(command, [name], {
			encoding: "utf8",
			stdio: ["ignore", "pipe", "pipe"],
			timeout: 5_000,
		});
		return output
			.split(/\r?\n/)
			.map((line) => line.trim())
			.find((path) => path.length > 0 && isExecutable(path));
	} catch {
		return undefined;
	}
}

export function resolveGrokBinary(env: NodeJS.ProcessEnv = process.env): string {
	const configured = env.PI_GROK_BUILD_BIN?.trim() || env.GROK_BIN?.trim();
	if (configured) {
		if (!isExecutable(configured)) throw new Error(`Configured Grok binary is not executable: ${configured}`);
		return configured;
	}

	const onPath = findOnPath("grok");
	if (onPath) return onPath;

	const standardPath = join(homedir(), ".grok", "bin", process.platform === "win32" ? "grok.exe" : "grok");
	if (isExecutable(standardPath)) return standardPath;

	throw new Error("Grok Build CLI not found. Install it from https://x.ai/cli and run `grok login`.");
}

export function getGrokVersion(binary: string): string {
	try {
		return execFileSync(binary, ["--version"], {
			encoding: "utf8",
			stdio: ["ignore", "pipe", "pipe"],
			timeout: 8_000,
		}).trim();
	} catch {
		return "unknown";
	}
}

export function discoverGrokModelIds(binary: string): string[] {
	try {
		const output = execFileSync(binary, ["models"], {
			encoding: "utf8",
			stdio: ["ignore", "pipe", "pipe"],
			timeout: 20_000,
		});
		const ids: string[] = [];
		for (const line of output.split(/\r?\n/)) {
			const match = line.match(/^\s*[*•-]\s+(\S+)/);
			const id = match?.[1]?.replace(/[(),]+$/g, "");
			if (id && !ids.includes(id)) ids.push(id);
		}
		return ids;
	} catch {
		return [];
	}
}