/**
 * 首次启动模板：优先业务项目 project-templates/，否则 kcode-pi 内置模板。
 * 支持 .trellis/、.kcode/、AGENTS.md、CLAUDE.md。
 */
import * as fs from "node:fs";
import * as path from "node:path";
import { fileURLToPath } from "node:url";

export function resolveKcodePiPackageRoot(fromDir = path.dirname(fileURLToPath(import.meta.url))): string {
	let current = path.resolve(fromDir);
	while (true) {
		const packageJson = path.join(current, "package.json");
		if (fs.existsSync(packageJson)) {
			try {
				const parsed = JSON.parse(fs.readFileSync(packageJson, "utf8"));
				if (parsed?.name === "kcode-pi") return current;
			} catch {
				// Keep walking; a malformed package.json should not hide a parent package.
			}
		}
		const parent = path.dirname(current);
		if (parent === current) return path.resolve(path.dirname(fileURLToPath(import.meta.url)), "../..");
		current = parent;
	}
}

const KCODE_PI_PACKAGE_ROOT = resolveKcodePiPackageRoot();

/** 批量拷贝子目录全部文件 */
function shouldSkipTemplateEntry(name: string): boolean {
	return name === "__pycache__" || name.endsWith(".pyc") || name.endsWith(".pyo");
}

function copyDir(src: string, dest: string): string[] {
	const created: string[] = [];
	if (!fs.existsSync(src)) return created;
	const entries = fs.readdirSync(src, { withFileTypes: true });
	for (const entry of entries) {
		if (shouldSkipTemplateEntry(entry.name)) continue;
		const s = path.join(src, entry.name);
		const d = path.join(dest, entry.name);
		if (entry.isDirectory()) {
			fs.mkdirSync(d, { recursive: true });
			created.push(...copyDir(s, d));
		} else if (entry.isFile()) {
			if (!fs.existsSync(d)) {
				fs.cpSync(s, d);
				created.push(d);
			}
		}
	}
	return created;
}

/** 从模板源拷贝 .trellis/ 到目标项目（仅不存在的文件，排除 spec/ 由 init 单独处理） */
export function initTrellisDir(cwd: string): string[] {
	const src = path.join(KCODE_PI_PACKAGE_ROOT, "project-templates", ".trellis");
	const dest = path.join(cwd, ".trellis");
	fs.mkdirSync(dest, { recursive: true });
	const created: string[] = [];
	const entries = fs.readdirSync(src, { withFileTypes: true });
	for (const entry of entries) {
		if (entry.name === "spec" || shouldSkipTemplateEntry(entry.name)) continue; // spec/ 由 init 按产品线选择拷贝
		const s = path.join(src, entry.name);
		const d = path.join(dest, entry.name);
		if (entry.isDirectory()) {
			fs.mkdirSync(d, { recursive: true });
			created.push(...copyDir(s, d));
		} else if (entry.isFile()) {
			if (!fs.existsSync(d)) {
				fs.cpSync(s, d);
				created.push(d);
			}
		}
	}
	return created;
}

/** 从模板源拷贝 .kcode/ 到目标项目（仅不存在的文件） */
export function initKcodeDir(cwd: string): string[] {
	const src = path.join(KCODE_PI_PACKAGE_ROOT, "project-templates", ".kcode");
	const dest = path.join(cwd, ".kcode");
	fs.mkdirSync(dest, { recursive: true });
	return copyDir(src, dest);
}

export function loadProjectTemplate(cwd: string, relativePath: string): string | undefined {
	const local = path.join(cwd, "project-templates", relativePath);
	const bundled = path.join(KCODE_PI_PACKAGE_ROOT, "project-templates", relativePath);
	try {
		return fs.readFileSync(local, "utf8");
	} catch {
		try {
			return fs.readFileSync(bundled, "utf8");
		} catch {
			return undefined;
		}
	}
}

export function loadAllInitTemplates(cwd: string): Record<string, string | undefined> {
	return {
		rootAgents: loadProjectTemplate(cwd, "AGENTS.md"),
		rootClaude: loadProjectTemplate(cwd, "CLAUDE.md"),
	};
}