"use strict";
/**
 * Binary discovery + child environment for GUI-context launches.
 *
 * macOS (Finder/launchd) and Windows (Explorer/scheduled-task) both start GUI
 * apps with a minimal PATH that cannot resolve the `#!/usr/bin/env node`
 * shebangs of dsh/npm. All spawned children therefore run through childEnv(),
 * which prepends the directories that actually hold dsh, npm, and node.
 */
const fs = require("node:fs");
const os = require("node:os");
const path = require("node:path");

const IS_WIN = process.platform === "win32";

function firstExisting(candidates) {
	for (const candidate of candidates) {
		try { if (candidate && fs.existsSync(candidate)) return candidate; } catch { /* next */ }
	}
	return null;
}

function pathDirs() {
	const sep = IS_WIN ? ";" : ":";
	return (process.env.PATH || "").split(sep).filter(Boolean);
}

/** The executable extension for node/npm shims (.cmd on Windows, else none). */
function exe(name) { return IS_WIN ? `${name}.cmd` : name; }

/**
 * The dsh binary: explicit override, common user install spots, then PATH.
 * On Windows, `npm i -g @deepseek-ai/dsh` places dsh.cmd in the npm prefix
 * (%APPDATA%\npm); on macOS, ~/.local/bin/dsh (a symlink to the package).
 */
function findDsh() {
	const override = process.env.DSH_DESKTOP_DSH_BIN;
	if (override) return override;
	const home = os.homedir();
	const appdata = process.env.APPDATA || path.join(home, "AppData", "Roaming");
	const candidates = IS_WIN ? [
		path.join(appdata, "npm", "dsh.cmd"),
		path.join(home, ".local", "bin", "dsh.cmd"),
		path.join(home, "AppData", "Roaming", "npm", "dsh.cmd"),
		...pathDirs().map((dir) => path.join(dir, "dsh.cmd")),
	] : [
		path.join(home, ".local/bin/dsh"),
		"/opt/homebrew/bin/dsh",
		"/usr/local/bin/dsh",
		...pathDirs().map((dir) => path.join(dir, "dsh")),
	];
	return firstExisting(candidates) || "dsh";
}

/** The npm binary: the same discovery strategy. */
function findNpm() {
	const home = os.homedir();
	const appdata = process.env.APPDATA || path.join(home, "AppData", "Roaming");
	const candidates = IS_WIN ? [
		path.join(appdata, "npm", "npm.cmd"),
		path.join(home, ".local", "bin", "npm.cmd"),
		path.join(home, "AppData", "Roaming", "npm", "npm.cmd"),
		...pathDirs().map((dir) => path.join(dir, "npm.cmd")),
	] : [
		path.join(home, ".local/bin/npm"),
		"/opt/homebrew/bin/npm",
		"/usr/local/bin/npm",
		...pathDirs().map((dir) => path.join(dir, "npm")),
	];
	return firstExisting(candidates) || "npm";
}

const DSH_BIN = findDsh();
const NPM_BIN = findNpm();

/**
 * Re-resolve the dsh binary right before every spawn. `npm install -g`
 * replaces the bin symlink/cmd during upgrades; a path captured at shell
 * startup would then hit ENOENT — exactly the upgrade-race failure in the wild.
 */
function resolveDsh() {
	return findDsh();
}

/** Environment (PATH augmented) for every child process we spawn. */
function childEnv() {
	const sep = IS_WIN ? ";" : ":";
	const dirs = [];
	for (const bin of [DSH_BIN, NPM_BIN]) {
		if (path.isAbsolute(bin)) dirs.push(path.dirname(bin));
		try { dirs.push(path.dirname(fs.realpathSync(bin))); } catch { /* not a file */ }
	}
	if (IS_WIN) {
		const appdata = process.env.APPDATA || path.join(os.homedir(), "AppData", "Roaming");
		dirs.push(path.join(appdata, "npm"));
		dirs.push(path.join(os.homedir(), ".local", "bin"));
	} else {
		dirs.push(
			path.join(os.homedir(), ".local/bin"),
			"/opt/homebrew/bin",
			"/usr/local/bin",
		);
	}
	const unique = [...new Set(dirs.filter(Boolean))];
	const augmented = unique.join(sep);
	const existing = process.env.PATH || "";
	return { ...process.env, PATH: existing ? `${augmented}${sep}${existing}` : augmented };
}

module.exports = { DSH_BIN, NPM_BIN, findDsh, findNpm, resolveDsh, childEnv, IS_WIN };