import { config } from '../../config';

Page({
  onLoad() {
    wx.showShareMenu({
      withShareTicket: true,
      menus: ['shareAppMessage', 'shareTimeline']
    });
  },
  onShareAppMessage() {
    return config.share;
  },
  onShareTimeline() {
    return config.share;
  },

  data: {
    categories: ['长度', '面积', '体积', '重量', '温度'],
    categoryIndex: 0,
    
    units: {
      '长度': [
        { name: '米', factor: 1 },
        { name: '千米', factor: 1000 },
        { name: '分米', factor: 0.1 },
        { name: '厘米', factor: 0.01 },
        { name: '毫米', factor: 0.001 },
        { name: '微米', factor: 0.000001 },
        { name: '纳米', factor: 0.000000001 },
        { name: '英里', factor: 1609.344 },
        { name: '海里', factor: 1852 },
        { name: '码', factor: 0.9144 },
        { name: '英尺', factor: 0.3048 },
        { name: '英寸', factor: 0.0254 }
      ],
      '面积': [
        { name: '平方米', factor: 1 },
        { name: '平方千米', factor: 1000000 },
        { name: '公顷', factor: 10000 },
        { name: '公亩', factor: 100 },
        { name: '平方英里', factor: 2589988.11 },
        { name: '英亩', factor: 4046.8564 },
        { name: '平方码', factor: 0.836127 },
        { name: '平方英尺', factor: 0.092903 },
        { name: '平方英寸', factor: 0.000645 }
      ],
      '体积': [
        { name: '立方米', factor: 1 },
        { name: '立方分米', factor: 0.001 },
        { name: '立方厘米', factor: 0.000001 },
        { name: '升', factor: 0.001 },
        { name: '分升', factor: 0.0001 },
        { name: '毫升', factor: 0.000001 },
        { name: '立方英尺', factor: 0.028317 },
        { name: '立方英寸', factor: 0.000016 },
        { name: '立方码', factor: 0.764555 }
      ],
      '重量': [
        { name: '千克', factor: 1 },
        { name: '克', factor: 0.001 },
        { name: '毫克', factor: 0.000001 },
        { name: '吨', factor: 1000 },
        { name: '磅', factor: 0.453592 },
        { name: '盎司', factor: 0.02835 },
        { name: '克拉', factor: 0.0002 }
      ],
      '温度': [
        { name: '摄氏度', type: 'C' },
        { name: '华氏度', type: 'F' },
        { name: '开氏度', type: 'K' }
      ]
    },
    
    currentUnits: [] as any[],
    fromIndex: 0,
    toIndex: 1,
    inputValue: '',
    outputValue: ''
  },

  onLoad() {
    this.updateCurrentUnits();
  },

  updateCurrentUnits() {
    const category = this.data.categories[this.data.categoryIndex];
    // @ts-ignore
    const units = this.data.units[category];
    this.setData({
      currentUnits: units,
      fromIndex: 0,
      toIndex: 1,
      inputValue: '',
      outputValue: ''
    });
  },

  bindCategoryChange(e: any) {
    this.setData({
      categoryIndex: e.detail.value
    });
    this.updateCurrentUnits();
  },

  bindFromUnitChange(e: any) {
    this.setData({
      fromIndex: e.detail.value
    });
    this.calculate();
  },

  bindToUnitChange(e: any) {
    this.setData({
      toIndex: e.detail.value
    });
    this.calculate();
  },

  bindInput(e: any) {
    this.setData({
      inputValue: e.detail.value
    });
    this.calculate();
  },

  calculate() {
    const val = parseFloat(this.data.inputValue);
    if (isNaN(val)) {
      this.setData({ outputValue: '' });
      return;
    }

    const category = this.data.categories[this.data.categoryIndex];
    if (category === '温度') {
      this.calculateTemperature(val);
    } else {
      this.calculateStandard(val);
    }
  },

  calculateStandard(val: number) {
    const fromUnit = this.data.currentUnits[this.data.fromIndex];
    const toUnit = this.data.currentUnits[this.data.toIndex];
    
    // Convert to base unit then to target unit
    const baseVal = val * fromUnit.factor;
    const result = baseVal / toUnit.factor;
    
    this.setData({
      outputValue: this.formatResult(result)
    });
  },

  calculateTemperature(val: number) {
    const fromUnit = this.data.currentUnits[this.data.fromIndex];
    const toUnit = this.data.currentUnits[this.data.toIndex];
    
    let celsius = val;
    // Convert to Celsius first
    if (fromUnit.type === 'F') {
      celsius = (val - 32) * 5 / 9;
    } else if (fromUnit.type === 'K') {
      celsius = val - 273.15;
    }
    
    // Convert from Celsius to target
    let result = celsius;
    if (toUnit.type === 'F') {
      result = celsius * 9 / 5 + 32;
    } else if (toUnit.type === 'K') {
      result = celsius + 273.15;
    }
    
    this.setData({
      outputValue: this.formatResult(result)
    });
  },
  
  swapUnits() {
    const { fromIndex, toIndex } = this.data;
    this.setData({
      fromIndex: toIndex,
      toIndex: fromIndex
    });
    this.calculate();
  },
  
  formatResult(val: number): string {
      if (Math.abs(val) < 0.000001 || Math.abs(val) > 10000000) {
          return val.toExponential(4);
      }
      return parseFloat(val.toPrecision(6)).toString();
  }
});