import { SpectrumRenderer, SpectrumRenderOptions, buildSpectrumPalette, hslToHex } from './SpectrumRenderer'

/**
 * 柱状频谱渲染器
 * 经典频率柱状条跳动，带峰值下落指示器
 */
export class BarSpectrumRenderer implements SpectrumRenderer {
  private peaks: number[] = []
  private peakVelocities: number[] = []

  render(ctx: CanvasRenderingContext2D, bands: number[], energy: number,
    width: number, height: number, brandColor: string, _options?: SpectrumRenderOptions): void {
    const bandCount: number = bands.length
    if (bandCount === 0) return

    // 初始化峰值数组
    if (this.peaks.length !== bandCount) {
      this.peaks = new Array<number>(bandCount)
      this.peakVelocities = new Array<number>(bandCount)
      for (let i = 0; i < bandCount; i++) {
        this.peaks[i] = 0
        this.peakVelocities[i] = 0
      }
    }

    // 轻微拖影，接近参考图中的荧光残影（使用透明背景）
    ctx.clearRect(0, 0, width, height)

    const gap: number = 1.0 // 减小间隙，增加柱子列数
    const barWidth: number = 5 // 固定柱子宽度
    const totalSpectrumWidth: number = bandCount * barWidth + (bandCount - 1) * gap
    const startX: number = (width - totalSpectrumWidth) / 2 // 居中起始位置
    const usableHeight: number = height * 0.60 // 减小最大高度
    const segmentHeight: number = Math.max(2, height * 0.012) // 减小单段高度
    const segmentGap: number = 0 // 去掉间隙，让方格紧密相连
    const segmentCount: number = Math.max(10, Math.floor(usableHeight / (segmentHeight + segmentGap)))
    const palette = buildSpectrumPalette(brandColor)
    const hueSpan: number = (palette.complementaryHue + 360 - palette.primaryHue) % 360

    // 地平线已移除，保持透明背景

    for (let i = 0; i < bandCount; i++) {
      const level: number = Math.max(0, Math.min(1, bands[i]))
      const activeSegments: number = Math.floor(level * segmentCount)
      const x: number = startX + i * (barWidth + gap)
      const hue: number = (palette.primaryHue + (i / bandCount) * hueSpan) % 360

      for (let seg = 0; seg < segmentCount; seg++) {
        const segY: number = height - (seg + 1) * (segmentHeight + segmentGap)
        const lit: boolean = seg < activeSegments

        // 只绘制点亮的方格，未点亮的不绘制（透明）
        if (!lit) {
          continue
        }

        const t: number = seg / segmentCount
        const lightness: number = 0.34 + t * 0.34
        const alpha: number = 0.55 + level * 0.45
        ctx.globalAlpha = alpha
        ctx.fillStyle = hslToHex(hue, 0.86, lightness)
        ctx.fillRect(x, segY, barWidth, segmentHeight)
      }
      ctx.globalAlpha = 1.0

      // 峰值下落指示器（亮点）
      if (level > this.peaks[i]) {
        this.peaks[i] = level
        this.peakVelocities[i] = 0
      } else {
        this.peakVelocities[i] += 0.0018
        this.peaks[i] -= this.peakVelocities[i]
        if (this.peaks[i] < 0) this.peaks[i] = 0
      }

      const peakSeg: number = Math.floor(this.peaks[i] * segmentCount)
      const peakY: number = height - (peakSeg + 1) * (segmentHeight + segmentGap)
      // 使用当前柱子的颜色
      const peakT: number = peakSeg / segmentCount
      const peakLightness: number = 0.34 + peakT * 0.34
      ctx.fillStyle = hslToHex(hue, 0.86, peakLightness)
      ctx.globalAlpha = 0.95
      ctx.fillRect(x, peakY, barWidth, segmentHeight + 1)
      ctx.globalAlpha = 1.0
    }
  }

  reset(): void {
    this.peaks = []
    this.peakVelocities = []
  }
}