import assert from "node:assert/strict";
import { mkdtempSync, realpathSync, rmSync } from "node:fs";
import { homedir, tmpdir } from "node:os";
import { join } from "node:path";
import test from "node:test";
import { bundledGentlePiAgentHome, gentlePiConfigHome } from "../lib/agent-home.ts";
import { setBundledInstallForTesting } from "../lib/gentle-shell-bundled.ts";

// The two Pi homes: `~/.pi/agent` holds Pi's own agent definitions and
// `~/.pi/gentle-ai` holds everything the Gentle AI commands own. Both are resolved
// once and shared, because the launch-time profile pin resolver reads the same
// profiles store the `/gentle:profiles` panel writes: two spellings of the override
// would silently read two different stores.

function isolatedHome(t: test.TestContext): string {
	const home = mkdtempSync(join(tmpdir(), "gentle-pi-config-home-"));
	const previousHome = process.env.HOME;
	const previousUserProfile = process.env.USERPROFILE;
	const previousConfigHome = process.env.GENTLE_PI_CONFIG_HOME;
	// Clear the higher-priority config override as well as isolating both OS homes.
	delete process.env.GENTLE_PI_CONFIG_HOME;
	process.env.HOME = home;
	process.env.USERPROFILE = home;
	t.after(() => {
		if (previousHome === undefined) delete process.env.HOME;
		else process.env.HOME = previousHome;
		if (previousUserProfile === undefined) delete process.env.USERPROFILE;
		else process.env.USERPROFILE = previousUserProfile;
		if (previousConfigHome === undefined) delete process.env.GENTLE_PI_CONFIG_HOME;
		else process.env.GENTLE_PI_CONFIG_HOME = previousConfigHome;
		rmSync(home, { recursive: true, force: true });
	});
	return home;
}

test("gentlePiConfigHome honours GENTLE_PI_CONFIG_HOME and otherwise falls back to ~/.pi/gentle-ai", (t) => {
	const home = isolatedHome(t);
	assert.equal(gentlePiConfigHome({ GENTLE_PI_CONFIG_HOME: "/custom/gentle-ai" }), "/custom/gentle-ai");
	assert.equal(gentlePiConfigHome({ GENTLE_PI_CONFIG_HOME: "" }), join(homedir(), ".pi", "gentle-ai"));
	assert.equal(gentlePiConfigHome({}), join(homedir(), ".pi", "gentle-ai"));
	assert.equal(gentlePiConfigHome(), join(homedir(), ".pi", "gentle-ai"));
	assert.equal(
		join(gentlePiConfigHome(), "profiles.json"),
		join(home, ".pi", "gentle-ai", "profiles.json"),
		"the store path is derived from the config home, not from the agent home",
	);
});

test("the isolated home restores defined and undefined config overrides", async (t) => {
	const previousConfigHome = process.env.GENTLE_PI_CONFIG_HOME;
	try {
		for (const inherited of [undefined, "/synthetic-inherited-config"]) {
			if (inherited === undefined) delete process.env.GENTLE_PI_CONFIG_HOME;
			else process.env.GENTLE_PI_CONFIG_HOME = inherited;
			await t.test(`inherited override: ${inherited === undefined ? "unset" : "set"}`, (child) => {
				const home = isolatedHome(child);
				assert.equal(process.env.GENTLE_PI_CONFIG_HOME, undefined);
				assert.equal(gentlePiConfigHome(), join(home, ".pi", "gentle-ai"));
			});
			assert.equal(process.env.GENTLE_PI_CONFIG_HOME, inherited);
		}
	} finally {
		if (previousConfigHome === undefined) delete process.env.GENTLE_PI_CONFIG_HOME;
		else process.env.GENTLE_PI_CONFIG_HOME = previousConfigHome;
	}
});

test("the config home ignores the Pi agent-home overrides", (t) => {
	const home = isolatedHome(t);
	// PI_CODING_AGENT_DIR and GENTLE_PI_AGENT_HOME move Pi's agent directory only.
	// Reusing that resolver here would point the profiles store at the agent home.
	assert.equal(
		gentlePiConfigHome({ PI_CODING_AGENT_DIR: "/pi/agent", GENTLE_PI_AGENT_HOME: "/gentle/agent" }),
		join(home, ".pi", "gentle-ai"),
	);
});

// S9: a bundled Gentle Shell keeps gentle-pi's config inside its prefix. It is
// derived from this package's bundled install and the launcher's
// GENTLE_SHELL_PREFIX, never exported (Gentle AI 4.0.0 reads
// GENTLE_PI_CONFIG_HOME as a parent folder). The testing overlay stands in for
// this package running from that install.
function bundledInstall(t: test.TestContext): string {
	const prefix = realpathSync(mkdtempSync(join(tmpdir(), "gentle-pi-bundled-config-")));
	setBundledInstallForTesting({ root: prefix });
	t.after(() => {
		setBundledInstallForTesting(undefined);
		rmSync(prefix, { recursive: true, force: true });
	});
	return prefix;
}

test("a bundled install derives the config home inside its prefix and the agent home from Pi's", (t) => {
	isolatedHome(t);
	const prefix = bundledInstall(t);
	const env = { GENTLE_SHELL_PREFIX: prefix, GENTLE_PI_CONFIG_HOME: "/home/ana/.pi/gentle-ai", PI_CODING_AGENT_DIR: "/agent" };
	assert.equal(gentlePiConfigHome(env), join(prefix, "config", "gentle-ai"));
	assert.equal(bundledGentlePiAgentHome(env), "/agent");
	// Another prefix, or none, is not this install: everything stays as before.
	for (const other of [{ GENTLE_PI_CONFIG_HOME: "/custom" }, { GENTLE_SHELL_PREFIX: join(prefix, "other"), GENTLE_PI_CONFIG_HOME: "/custom" }]) {
		assert.equal(gentlePiConfigHome(other), "/custom");
		assert.equal(bundledGentlePiAgentHome({ ...other, PI_CODING_AGENT_DIR: "/agent" }), undefined);
	}
	assert.equal(gentlePiConfigHome({ GENTLE_PI_CONFIG_HOME: "" }), join(homedir(), ".pi", "gentle-ai"));
});