/**
 * 个人规则管理工具
 * 功能：读写个人规则文件
 * 依赖：vscode, fs, path
 * 使用场景：保存和加载用户的个人规则
 */

import * as vscode from 'vscode';
import * as fs from 'fs';
import * as path from 'path';
import * as os from 'os';

/**
 * 获取规则目录路径
 */
function getRulesDir(): string {
  return path.join(os.homedir(), '.iccoder', 'rules');
}

/**
 * 确保规则目录存在
 */
function ensureRulesDir(): void {
  const dir = getRulesDir();
  if (!fs.existsSync(dir)) {
    fs.mkdirSync(dir, { recursive: true });
  }
}

/**
 * 从文件内容中提取规则名称
 */
function extractRuleName(content: string): string {
  const lines = content.split('\n');
  const firstLine = lines[0]?.trim();
  if (firstLine && firstLine.startsWith('# ')) {
    return firstLine.substring(2).trim();
  }
  return content.substring(0, 30) + (content.length > 30 ? '...' : '');
}

/**
 * 保存新规则
 */
export async function savePersonalRule(name: string, content: string, enabled: boolean): Promise<boolean> {
  try {
    ensureRulesDir();

    const timestamp = Date.now();
    const filename = `rule-${timestamp}.md`;
    const filePath = path.join(getRulesDir(), filename);

    const fileContent = `# ${name}\n\n${content}`;
    fs.writeFileSync(filePath, fileContent, 'utf-8');

    await vscode.workspace.getConfiguration('ic-coder').update('personalRulesEnabled', enabled, vscode.ConfigurationTarget.Global);

    vscode.window.showInformationMessage('规则已保存');
    return true;
  } catch (error) {
    vscode.window.showErrorMessage(`保存规则失败: ${error}`);
    return false;
  }
}

/**
 * 更新规则
 */
export async function updatePersonalRule(filename: string, name: string, content: string, enabled: boolean): Promise<boolean> {
  try {
    const filePath = path.join(getRulesDir(), filename);
    const fileContent = `# ${name}\n\n${content}`;
    fs.writeFileSync(filePath, fileContent, 'utf-8');

    await vscode.workspace.getConfiguration('ic-coder').update('personalRulesEnabled', enabled, vscode.ConfigurationTarget.Global);

    vscode.window.showInformationMessage('规则已更新');
    return true;
  } catch (error) {
    vscode.window.showErrorMessage(`更新规则失败: ${error}`);
    return false;
  }
}

/**
 * 删除规则
 */
export async function deletePersonalRule(filename: string): Promise<boolean> {
  try {
    const filePath = path.join(getRulesDir(), filename);
    if (fs.existsSync(filePath)) {
      fs.unlinkSync(filePath);
      vscode.window.showInformationMessage('规则已删除');
      return true;
    }
    return false;
  } catch (error) {
    vscode.window.showErrorMessage(`删除规则失败: ${error}`);
    return false;
  }
}

/**
 * 加载所有规则
 */
export function loadPersonalRules(): { rules: Array<{ filename: string; name: string; content: string }>; enabled: boolean } {
  const enabled = vscode.workspace.getConfiguration('ic-coder').get<boolean>('personalRulesEnabled', true);
  const dir = getRulesDir();

  if (!fs.existsSync(dir)) {
    return { rules: [], enabled };
  }

  try {
    const files = fs.readdirSync(dir).filter(f => f.endsWith('.md'));
    const rules = files.map(filename => {
      const content = fs.readFileSync(path.join(dir, filename), 'utf-8');
      const lines = content.split('\n');
      let name = '';
      let actualContent = content;

      if (lines[0]?.trim().startsWith('# ')) {
        name = lines[0].substring(2).trim();
        actualContent = lines.slice(2).join('\n').trim();
      } else {
        name = extractRuleName(content);
      }

      return { filename, name, content: actualContent };
    });
    return { rules, enabled };
  } catch (error) {
    console.error('读取规则失败:', error);
    return { rules: [], enabled };
  }
}

/**
 * 获取当前生效的所有规则内容
 */
export function getActiveRules(): string | null {
  const { rules, enabled } = loadPersonalRules();
  if (!enabled || rules.length === 0) {
    return null;
  }
  return rules.map(r => r.content).join('\n\n');
}