/**
 * 查询模板管理
 * 用于保存常用查询模板
 */

const STORAGE_KEY = 'db-cli:query-templates'

// 默认模板
const DEFAULT_TEMPLATES = [
  {
    id: 'template-1',
    name: '查询所有数据',
    description: '查询表中所有数据',
    query: 'SELECT * FROM table_name WHERE 1=1;',
    category: '基础查询'
  },
  {
    id: 'template-2',
    name: '分页查询',
    description: '带分页的数据查询',
    query: 'SELECT * FROM table_name WHERE 1=1 LIMIT 10 OFFSET 0;',
    category: '分页'
  },
  {
    id: 'template-3',
    name: '统计查询',
    description: '统计数据行数',
    query: 'SELECT COUNT(*) as total FROM table_name WHERE 1=1;',
    category: '统计'
  },
  {
    id: 'template-4',
    name: '插入数据',
    description: '插入单条数据',
    query: 'INSERT INTO table_name (column1, column2) VALUES (value1, value2);',
    category: '插入'
  },
  {
    id: 'template-5',
    name: '更新数据',
    description: '更新指定条件的数据',
    query: 'UPDATE table_name SET column1 = value1 WHERE id = 1;',
    category: '更新'
  },
  {
    id: 'template-6',
    name: '删除数据',
    description: '删除指定条件的数据',
    query: 'DELETE FROM table_name WHERE id = 1;',
    category: '删除'
  },
  {
    id: 'template-redis-1',
    name: 'Redis - 设置键值',
    description: 'SET 命令',
    query: 'SET key value',
    category: 'Redis',
    dbType: 'redis'
  },
  {
    id: 'template-redis-2',
    name: 'Redis - 获取键值',
    description: 'GET 命令',
    query: 'GET key',
    category: 'Redis',
    dbType: 'redis'
  },
  {
    id: 'template-mongo-1',
    name: 'MongoDB - 查询数据',
    description: 'find 查询',
    query: 'db.collection.find({ field: value })',
    category: 'MongoDB',
    dbType: 'mongodb'
  }
]

export function useQueryTemplates() {
  /**
   * 获取模板列表
   */
  const getTemplates = () => {
    try {
      const stored = localStorage.getItem(STORAGE_KEY)
      if (!stored) {
        // 首次使用，保存默认模板
        localStorage.setItem(STORAGE_KEY, JSON.stringify(DEFAULT_TEMPLATES))
        return DEFAULT_TEMPLATES
      }
      return JSON.parse(stored)
    } catch (e) {
      console.error('Failed to load query templates:', e)
      return DEFAULT_TEMPLATES
    }
  }

  /**
   * 保存模板
   */
  const saveTemplate = (template) => {
    const templates = getTemplates()
    const newTemplate = {
      id: `template-${Date.now()}`,
      name: template.name || '未命名模板',
      description: template.description || '',
      query: template.query,
      category: template.category || '自定义',
      dbType: template.dbType || 'mysql',
      createdAt: new Date().toISOString()
    }

    const updated = [...templates, newTemplate]

    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(updated))
      return newTemplate
    } catch (e) {
      console.error('Failed to save query template:', e)
      return null
    }
  }

  /**
   * 更新模板
   */
  const updateTemplate = (id, updates) => {
    const templates = getTemplates()
    const index = templates.findIndex(t => t.id === id)

    if (index === -1) return null

    templates[index] = {
      ...templates[index],
      ...updates,
      updatedAt: new Date().toISOString()
    }

    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(templates))
      return templates[index]
    } catch (e) {
      console.error('Failed to update query template:', e)
      return null
    }
  }

  /**
   * 删除模板
   */
  const deleteTemplate = (id) => {
    const templates = getTemplates()
    const filtered = templates.filter(t => t.id !== id)

    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(filtered))
      return true
    } catch (e) {
      console.error('Failed to delete query template:', e)
      return false
    }
  }

  /**
   * 根据数据库类型筛选模板
   */
  const getTemplatesByType = (dbType) => {
    const templates = getTemplates()
    if (!dbType) return templates

    // 通用模板（无 dbType） + 匹配当前 dbType 的模板
    return templates.filter(t => !t.dbType || t.dbType === dbType.toLowerCase())
  }

  /**
   * 重置为默认模板
   */
  const resetToDefaults = () => {
    try {
      localStorage.setItem(STORAGE_KEY, JSON.stringify(DEFAULT_TEMPLATES))
      return true
    } catch (e) {
      console.error('Failed to reset query templates:', e)
      return false
    }
  }

  return {
    getTemplates,
    saveTemplate,
    updateTemplate,
    deleteTemplate,
    getTemplatesByType,
    resetToDefaults
  }
}