// components/navbar/navbar.js
Component({
  properties: {
    // 标题
    title: {
      type: String,
      value: ''
    },
    // 是否显示返回按钮
    showBack: {
      type: Boolean,
      value: true
    },
    // 返回按钮文字
    backText: {
      type: String,
      value: '返回'
    },
    // 背景色（支持渐变）
    background: {
      type: String,
      value: 'linear-gradient(135deg, #667eea 0%, #764ba2 100%)'
    }
  },

  data: {
    statusBarHeight: 0,
    menuButtonTop: 0,
    menuButtonHeight: 0,
    navbarHeight: 0
  },

  lifetimes: {
    attached() {
      this.setNavBarInfo()
    }
  },

  methods: {
    // 设置导航栏信息
    setNavBarInfo() {
      const windowInfo = wx.getWindowInfo()
      const menuButtonInfo = wx.getMenuButtonBoundingClientRect()

      const statusBarHeight = windowInfo.statusBarHeight
      const menuButtonTop = menuButtonInfo.top
      const menuButtonHeight = menuButtonInfo.height

      // 导航栏总高度 = 胶囊按钮bottom + 胶囊按钮到顶部的距离
      const navbarHeight = menuButtonInfo.bottom + (menuButtonTop - statusBarHeight)

      this.setData({
        statusBarHeight,
        menuButtonTop,
        menuButtonHeight,
        navbarHeight
      })
    },

    // 返回按钮点击
    onBackTap() {
      this.triggerEvent('back')

      // 如果没有监听back事件，默认返回上一页
      const pages = getCurrentPages()
      if (pages.length > 1) {
        wx.navigateBack()
      } else {
        wx.switchTab({
          url: '/pages/index/index'
        })
      }
    }
  }
})