package waveform

// Block characters for waveform rendering (bottom to top)
var blocks = []rune{' ', '▁', '▂', '▃', '▄', '▅', '▆', '▇', '█'}

// RenderWaveform converts normalized samples (0-1) to block characters
func RenderWaveform(samples []float64, width int) string {
	if len(samples) == 0 {
		return ""
	}

	result := make([]rune, width)

	for i := 0; i < width; i++ {
		// Map position to sample index
		sampleIdx := i * len(samples) / width
		if sampleIdx >= len(samples) {
			sampleIdx = len(samples) - 1
		}

		// Get sample value and map to block character
		value := samples[sampleIdx]
		if value < 0 {
			value = 0
		}
		if value > 1 {
			value = 1
		}

		blockIdx := int(value * float64(len(blocks)-1))
		result[i] = blocks[blockIdx]
	}

	return string(result)
}

// RenderWaveformWithNeedle renders the waveform with a position indicator
func RenderWaveformWithNeedle(samples []float64, width int, position float64) (string, int) {
	waveform := RenderWaveform(samples, width)

	// Calculate needle position
	needlePos := int(position * float64(width))
	if needlePos < 0 {
		needlePos = 0
	}
	if needlePos >= width {
		needlePos = width - 1
	}

	return waveform, needlePos
}

// RenderWithColors returns the waveform with the needle position marked
// Returns: left part, needle char, right part
func RenderWithColors(samples []float64, width int, position float64) (string, string, string) {
	waveform := []rune(RenderWaveform(samples, width))
	if len(waveform) == 0 {
		return "", "|", ""
	}

	needlePos := int(position * float64(len(waveform)))
	if needlePos < 0 {
		needlePos = 0
	}
	if needlePos >= len(waveform) {
		needlePos = len(waveform) - 1
	}

	left := string(waveform[:needlePos])
	needle := "|"
	right := ""
	if needlePos+1 < len(waveform) {
		right = string(waveform[needlePos+1:])
	}

	return left, needle, right
}