terminal-chart-server/internal/renderer/text.go

package renderer

import (
	"fmt"
	"strings"

	"github.com/picoclaw/chart/internal/types"
)

type TextRenderer struct {
	width  int
	height int
}

func NewTextRenderer() *TextRenderer {
	return &TextRenderer{
		width:  60,
		height: 15,
	}
}

func (r *TextRenderer) Render(chart *types.Chart) ([]byte, error) {
	var sb strings.Builder

	if chart.Title != "" {
		sb.WriteString(fmt.Sprintf("[ Chart: %s ]\n", chart.Title))
	}

	if len(chart.Data.Datasets) == 0 {
		sb.WriteString("No data available.\n")
		return []byte(sb.String()), nil
	}

	switch chart.Type {
	case types.ChartTypePie, types.ChartTypeDonut:
		r.renderPieChart(&sb, &chart.Data)
	case types.ChartTypeBubble:
		r.renderBubbleChart(&sb, &chart.Data)
	case types.ChartTypeMixed:
		r.renderMixedChart(&sb, &chart.Data)
	case types.ChartTypePolar, types.ChartTypeRadar:
		r.renderRadarLikeChart(&sb, &chart.Data)
	default:
		r.renderBarLikeChart(&sb, &chart.Data)
	}

	return []byte(sb.String()), nil
}

func (r *TextRenderer) renderPieChart(sb *strings.Builder, data *types.ChartData) {
	dataset := data.Datasets[0]
	values := dataset.Values
	labels := data.Labels

	total := 0.0
	for _, v := range values {
		total += v
	}

	for i, v := range values {
		label := fmt.Sprintf("Item %d", i+1)
		if i < len(labels) {
			label = labels[i]
		}

		percentage := v / total * 100

		barLen := int(percentage / 4)
		if barLen > 12 {
			barLen = 12
		}
		bar := strings.Repeat("#", barLen)

		sb.WriteString(fmt.Sprintf("%-12s |%s [%.1f%%]\n", label, bar, percentage))
	}
}

func (r *TextRenderer) renderBubbleChart(sb *strings.Builder, data *types.ChartData) {
	dataset := data.Datasets[0]
	labels := data.Labels
	if len(labels) == 0 {
		labels = make([]string, len(dataset.Values))
		for i := range labels {
			labels[i] = fmt.Sprintf("X%d", i+1)
		}
	}

	maxValue := dataset.Values[0]
	for _, v := range dataset.Values {
		if v > maxValue {
			maxValue = v
		}
	}

	for i, value := range dataset.Values {
		label := labels[i]
		bubbleSize := 2 + int((value/maxValue)*5)

		bubble := strings.Repeat("o", bubbleSize)

		sb.WriteString(fmt.Sprintf("%-8s |%s %.2f\n", label, bubble, value))
	}
}

func (r *TextRenderer) renderMixedChart(sb *strings.Builder, data *types.ChartData) {
	dataset := data.Datasets[0]
	labels := data.Labels
	if len(labels) == 0 {
		labels = make([]string, len(dataset.Values))
		for i := range labels {
			labels[i] = fmt.Sprintf("X%d", i+1)
		}
	}

	maxValue := dataset.Values[0]
	for _, v := range dataset.Values {
		if v > maxValue {
			maxValue = v
		}
	}

	for i, value := range dataset.Values {
		label := labels[i]

		barLen := int((value / maxValue) * float64(r.width-20))
		if barLen < 1 {
			barLen = 1
		}

		bar := strings.Repeat("#", barLen)

		sb.WriteString(fmt.Sprintf("%-8s |%s %.2f [mixed]\n", label, bar, value))
	}
}

func (r *TextRenderer) renderRadarLikeChart(sb *strings.Builder, data *types.ChartData) {
	dataset := data.Datasets[0]
	values := dataset.Values
	labels := data.Labels

	maxValue := values[0]
	for _, v := range values {
		if v > maxValue {
			maxValue = v
		}
	}

	sb.WriteString(fmt.Sprintf("[ Radar/Polar Chart: %d dimensions ]\n", len(values)))

	for i, v := range values {
		label := fmt.Sprintf("Dim %d", i+1)
		if i < len(labels) {
			label = labels[i]
		}

		barLen := int((v / maxValue) * float64(r.width-25))
		if barLen < 1 {
			barLen = 1
		}

		bar := strings.Repeat("#", barLen)

		sb.WriteString(fmt.Sprintf("%-12s |%s %.2f\n", label, bar, v))
	}
}

func (r *TextRenderer) renderBarLikeChart(sb *strings.Builder, data *types.ChartData) {
	dataset := data.Datasets[0]
	labels := data.Labels
	if len(labels) == 0 {
		labels = make([]string, len(dataset.Values))
		for i := range labels {
			labels[i] = fmt.Sprintf("X%d", i+1)
		}
	}

	maxValue := dataset.Values[0]
	for _, v := range dataset.Values {
		if v > maxValue {
			maxValue = v
		}
	}

	for i, value := range dataset.Values {
		label := labels[i]
		if i >= len(labels) {
			label = fmt.Sprintf("X%d", i+1)
		}

		barLen := int((value / maxValue) * float64(r.width-20))
		if barLen < 1 {
			barLen = 1
		}

		bar := strings.Repeat("#", barLen)
		sb.WriteString(fmt.Sprintf("%-8s |%s %.2f\n", label, bar, value))
	}
}