import { Plugin } from 'chart.js'

/**
 * 饼图中心文本插件
 * 在 Doughnut/Pie 图表中心显示总金额
 */

export interface PieCenterTextOptions {
  text?: string
  subtext?: string
  textColor?: string
  subtextColor?: string
  fontSize?: number
  subFontSize?: number
}

export const pieCenterTextPlugin: Plugin = {
  id: 'pieCenterText',
  afterDraw: (chart: any) => {
    const { ctx, chartArea } = chart

    if (!chartArea) return

    // 计算中心点
    const centerX = (chartArea.left + chartArea.right) / 2
    const centerY = (chartArea.top + chartArea.bottom) / 2

    // 从图表配置中获取插件选项
    const pluginOptions = chart.options.plugins?.pieCenterText as PieCenterTextOptions | undefined

    if (!pluginOptions) return

    const { text, subtext, textColor, subtextColor, fontSize, subFontSize } = pluginOptions

    ctx.save()
    ctx.textAlign = 'center'
    ctx.textBaseline = 'middle'

    // 计算字体大小（基于图表高度）
    const chartHeight = chartArea.bottom - chartArea.top
    const defaultFontSize = Math.max(14, Math.min(32, chartHeight * 0.2))
    const defaultSubFontSize = Math.max(10, Math.min(16, chartHeight * 0.12))

    // 绘制主文本（金额）
    if (text) {
      ctx.font = `bold ${fontSize || defaultFontSize}px -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif`
      ctx.fillStyle = textColor || '#323233'
      ctx.fillText(text, centerX, centerY - 5)
    }

    // 绘制副文本（标签，如"总支出"）
    if (subtext) {
      ctx.font = `${subFontSize || defaultSubFontSize}px -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif`
      ctx.fillStyle = subtextColor || '#969799'
      ctx.fillText(subtext, centerX, centerY + (fontSize || defaultFontSize) * 0.6)
    }

    ctx.restore()
  }
}