/**
 * config.test.ts — Unit tests for the configuration module.
 *
 * Tests cover:
 * - Default configuration creation
 * - Validation of each config field
 * - Partial and full updates via setConfig
 * - File persistence (save/load)
 * - Config file path resolution
 * - Reset to defaults
 * - Edge cases (edge values, missing files, invalid JSON)
 *
 * @module file-claiming/config.test
 */

import { existsSync, readFileSync, writeFileSync, mkdirSync } from "node:fs";
import { join } from "node:path";
import { assert, createTempDir, cleanupTempDir } from "./test-utils.ts";

// ---------------------------------------------------------------------------
// Module under test
// ---------------------------------------------------------------------------

import {
	createDefaultConfig,
	validateConfig,
	getConfig,
	setConfig,
	resetConfig,
	getConfigFilePath,
	loadConfigFromFile,
	saveConfigToFile,
} from "../src/config";

// ---------------------------------------------------------------------------
// Test: Default configuration
// ---------------------------------------------------------------------------

function testDefaultConfig() {
	const def = createDefaultConfig();
	assert(typeof def.autoReleaseTTL === "number", "autoReleaseTTL is a number");
	assert(def.autoReleaseTTL === 300_000, "Default TTL is 300000ms");
	assert(def.releaseOnTurnEnd === true, "Default releaseOnTurnEnd is true");
	assert(typeof def.lockDir === "string", "lockDir is a string");
	assert(def.lockDir.length > 0, "lockDir is non-empty");
	assert(Array.isArray(def.blockedTools), "blockedTools is an array");
	assert(def.blockedTools.includes("edit"), "blockedTools includes 'edit'");
	assert(def.blockedTools.includes("write"), "blockedTools includes 'write'");
	assert(def.showDiagnostics === true, "Default showDiagnostics is true");

	const def2 = createDefaultConfig();
	assert(def !== def2, "Each call returns a fresh object");
	assert(
		JSON.stringify(def) === JSON.stringify(def2),
		"Fresh copies have same values",
	);

	console.log("✅ Config: default configuration is correct");
}

// ---------------------------------------------------------------------------
// Test: Validation
// ---------------------------------------------------------------------------

function testValidation() {
	let result = validateConfig({ autoReleaseTTL: 600_000 });
	assert(result.valid === true, "Valid autoReleaseTTL passes");
	assert(result.errors.length === 0, "No errors for valid config");

	result = validateConfig({ releaseOnTurnEnd: false });
	assert(result.valid === true, "Valid releaseOnTurnEnd passes");

	result = validateConfig({ showDiagnostics: false });
	assert(result.valid === true, "Valid showDiagnostics passes");

	result = validateConfig({ blockedTools: [] });
	assert(result.valid === true, "Empty blockedTools is valid");

	result = validateConfig({ blockedTools: ["edit", "write", "bash"] });
	assert(result.valid === true, "Multiple blockedTools is valid");

	result = validateConfig({ lockDir: "/tmp/locks" });
	assert(result.valid === true, "Valid lockDir passes");

	result = validateConfig({ autoReleaseTTL: 0 });
	assert(result.valid === true, "Zero autoReleaseTTL is valid");

	result = validateConfig({ autoReleaseTTL: -1 } as any);
	assert(result.valid === false, "Negative autoReleaseTTL is invalid");

	result = validateConfig({ autoReleaseTTL: "abc" } as any);
	assert(result.valid === false, "String autoReleaseTTL is invalid");

	result = validateConfig({ autoReleaseTTL: NaN } as any);
	assert(result.valid === false, "NaN autoReleaseTTL is invalid");

	result = validateConfig({ releaseOnTurnEnd: "yes" } as any);
	assert(result.valid === false, "String releaseOnTurnEnd is invalid");

	result = validateConfig({ lockDir: "" } as any);
	assert(result.valid === false, "Empty lockDir is invalid");

	result = validateConfig({ lockDir: 123 } as any);
	assert(result.valid === false, "Number lockDir is invalid");

	result = validateConfig({ blockedTools: "edit" } as any);
	assert(result.valid === false, "String blockedTools is invalid");

	result = validateConfig({ blockedTools: [1, 2] } as any);
	assert(result.valid === false, "Number array blockedTools is invalid");

	result = validateConfig({ showDiagnostics: 1 } as any);
	assert(result.valid === false, "Number showDiagnostics is invalid");

	result = validateConfig({
		autoReleaseTTL: "bad",
		releaseOnTurnEnd: "bad",
		showDiagnostics: "bad",
	} as any);
	assert(result.valid === false, "Multiple invalid fields produce errors");
	assert(result.errors.length >= 3, "Multiple errors reported");

	console.log("✅ Config: validation works correctly");
}

// ---------------------------------------------------------------------------
// Test: Runtime get/set
// ---------------------------------------------------------------------------

function testGetSet() {
	resetConfig();

	const def = getConfig();
	assert(def.autoReleaseTTL === 300_000, "getConfig returns defaults");

	const result = setConfig({ autoReleaseTTL: 600_000 });
	assert(result.valid === true, "setConfig with valid value succeeds");
	assert(result.errors.length === 0, "No errors");

	const updated = getConfig();
	assert(updated.autoReleaseTTL === 600_000, "Config value updated");
	assert(updated.releaseOnTurnEnd === true, "Other values unchanged");

	const fail = setConfig({ autoReleaseTTL: -1 } as any);
	assert(fail.valid === false, "setConfig with invalid value fails");
	assert(fail.errors.length > 0, "Error reported");

	const unchanged = getConfig();
	assert(unchanged.autoReleaseTTL === 600_000, "Config unchanged on failure");

	setConfig({
		autoReleaseTTL: 30_000,
		releaseOnTurnEnd: false,
		showDiagnostics: false,
	});
	const multi = getConfig();
	assert(multi.autoReleaseTTL === 30_000, "Multi-set: TTL updated");
	assert(
		multi.releaseOnTurnEnd === false,
		"Multi-set: releaseOnTurnEnd updated",
	);
	assert(multi.showDiagnostics === false, "Multi-set: showDiagnostics updated");

	resetConfig();
	console.log("✅ Config: runtime get/set works correctly");
}

// ---------------------------------------------------------------------------
// Test: Config file path resolution
// ---------------------------------------------------------------------------

function testConfigFilePath() {
	const path = getConfigFilePath();
	assert(
		path.endsWith("config.json"),
		"Config file path ends with config.json",
	);

	const customPath = getConfigFilePath("/tmp/custom-locks");
	assert(
		customPath.startsWith("/tmp/custom-locks"),
		"Custom lockDir reflected",
	);
	assert(
		customPath.endsWith("config.json"),
		"Custom path ends with config.json",
	);

	console.log("✅ Config: file path resolution works");
}

// ---------------------------------------------------------------------------
// Test: File persistence (save/load)
// ---------------------------------------------------------------------------

async function testFilePersistence() {
	resetConfig();
	const tempDir = createTempDir("config-test-");

	setConfig({ lockDir: tempDir });
	await saveConfigToFile();

	const configPath = getConfigFilePath(tempDir);
	assert(existsSync(configPath), "Config file created on disk");

	const raw = readFileSync(configPath, "utf-8");
	const parsed = JSON.parse(raw);
	assert(parsed.autoReleaseTTL === 300_000, "Saved config has correct TTL");
	assert(
		parsed.releaseOnTurnEnd === true,
		"Saved config has correct releaseOnTurnEnd",
	);

	setConfig({ autoReleaseTTL: 600_000 });
	await saveConfigToFile();

	const raw2 = readFileSync(configPath, "utf-8");
	const parsed2 = JSON.parse(raw2);
	assert(parsed2.autoReleaseTTL === 600_000, "Updated config saved correctly");

	setConfig({ autoReleaseTTL: 1000 });
	await loadConfigFromFile(configPath);
	const afterReload = getConfig();
	assert(
		afterReload.autoReleaseTTL === 600_000,
		"Loaded config overrides in-memory",
	);

	const nonExistent = join(tempDir, "nonexistent", "config.json");
	await loadConfigFromFile(nonExistent);
	const stillLoaded = getConfig();
	assert(
		stillLoaded.autoReleaseTTL === 600_000,
		"Non-existent file keeps current config",
	);

	resetConfig();
	cleanupTempDir(tempDir);
	console.log("✅ Config: file persistence works");
}

// ---------------------------------------------------------------------------
// Test: Load from corrupted file
// ---------------------------------------------------------------------------

async function testCorruptedFile() {
	resetConfig();
	const tempDir = createTempDir("config-corrupt-");
	const configPath = getConfigFilePath(tempDir);

	mkdirSync(tempDir, { recursive: true });
	writeFileSync(configPath, "{invalid json}", "utf-8");

	const result = await loadConfigFromFile(configPath);
	assert(result.autoReleaseTTL === 300_000, "Corrupted file keeps defaults");

	writeFileSync(
		configPath,
		JSON.stringify({ autoReleaseTTL: "invalid", releaseOnTurnEnd: false }),
		"utf-8",
	);

	await loadConfigFromFile(configPath);
	const after = getConfig();
	assert(
		after.autoReleaseTTL === 300_000,
		"Invalid field skipped, keeps default",
	);
	assert(
		after.releaseOnTurnEnd === false,
		"Valid field applied from corrupted file",
	);

	resetConfig();
	cleanupTempDir(tempDir);
	console.log("✅ Config: corrupted file handling works");
}

// ---------------------------------------------------------------------------
// Test: Reset to defaults
// ---------------------------------------------------------------------------

function testReset() {
	setConfig({ autoReleaseTTL: 999_999, showDiagnostics: false });
	const modified = getConfig();
	assert(modified.autoReleaseTTL === 999_999, "Modified TTL");

	resetConfig();
	const restored = getConfig();
	assert(restored.autoReleaseTTL === 300_000, "Reset restores default TTL");
	assert(
		restored.showDiagnostics === true,
		"Reset restores default showDiagnostics",
	);
	console.log("✅ Config: reset to defaults works");
}

// ---------------------------------------------------------------------------
// Test: Config immutability
// ---------------------------------------------------------------------------

function testImmutability() {
	resetConfig();
	const first = getConfig();
	const second = getConfig();
	(first as any).autoReleaseTTL = 999_999;
	assert(
		second.autoReleaseTTL === 300_000,
		"getConfig returns independent copies",
	);
	console.log("✅ Config: immutability of getConfig is preserved");
}

// ---------------------------------------------------------------------------
// Test: Edge values
// ---------------------------------------------------------------------------

function testEdgeValues() {
	resetConfig();

	let result = setConfig({ autoReleaseTTL: Number.MAX_SAFE_INTEGER });
	assert(result.valid === true, "MAX_SAFE_INTEGER TTL is valid");

	result = setConfig({ autoReleaseTTL: Infinity });
	assert(result.valid === false, "Infinity TTL is invalid");

	result = setConfig({ blockedTools: [] });
	assert(result.valid === true, "Empty blockedTools is valid");

	const longDir = "/" + "a".repeat(1000);
	result = setConfig({ lockDir: longDir });
	assert(result.valid === true, "Long lockDir is valid");

	resetConfig();
	console.log("✅ Config: edge values handled correctly");
}

// ---------------------------------------------------------------------------
// Test runner
// ---------------------------------------------------------------------------

async function runTests() {
	console.log("Running Config Module Tests\n");

	const tests = [
		testDefaultConfig,
		testValidation,
		testGetSet,
		testConfigFilePath,
		testFilePersistence,
		testCorruptedFile,
		testReset,
		testImmutability,
		testEdgeValues,
	];

	try {
		for (const test of tests) {
			try {
				await test();
			} catch (err) {
				console.error(`\n❌ Test ${test.name} failed: ${err}`);
				throw err;
			}
		}
		console.log("\n✅ All config module tests passed!");
	} catch (err) {
		console.error(`\n❌ Test suite failed: ${err}`);
		process.exit(1);
	}
}

runTests();