package chart

import (
	"strings"
	"testing"
	"time"

	"powerwatts/internal/store"
)

func TestFormatGermanNumber(t *testing.T) {
	tests := map[int]string{
		0:       "0",
		12:      "12",
		999:     "999",
		1000:    "1.000",
		10000:   "10.000",
		1234567: "1.234.567",
		-1000:   "-1.000",
	}
	for input, want := range tests {
		if got := FormatGermanNumber(input); got != want {
			t.Fatalf("FormatGermanNumber(%d) = %q, want %q", input, got, want)
		}
	}
}

func TestBuildHistoryChartEmpty(t *testing.T) {
	chart := BuildHistoryChart(nil, 0)
	if !strings.Contains(string(chart), "No power history yet") {
		t.Fatalf("empty chart did not contain fallback text: %s", string(chart))
	}
}

func TestBuildHistoryChartRendersPolyline(t *testing.T) {
	history := []store.Sample{
		{At: time.Date(2026, 4, 20, 0, 0, 0, 0, time.UTC), Value: 100},
		{At: time.Date(2026, 4, 20, 6, 0, 0, 0, time.UTC), Value: 200},
		{At: time.Date(2026, 4, 20, 12, 0, 0, 0, time.UTC), Value: 150},
	}

	chartHTML := BuildHistoryChart(history, 0)
	if !strings.Contains(string(chartHTML), "<polyline") {
		t.Fatalf("chart did not contain polyline: %s", string(chartHTML))
	}
	for _, want := range []string{"W", "00:00", "06:00", "12:00"} {
		if !strings.Contains(string(chartHTML), want) {
			t.Fatalf("chart did not include %q: %s", want, string(chartHTML))
		}
	}
	if !strings.Contains(string(chartHTML), "0 W") {
		t.Fatalf("chart did not include zero baseline: %s", string(chartHTML))
	}
}

func TestBuildHistoryChartUsesConfiguredMax(t *testing.T) {
	history := []store.Sample{{At: time.Date(2026, 4, 20, 12, 0, 0, 0, time.UTC), Value: 250}}
	chartHTML := BuildHistoryChart(history, 1000)
	if !strings.Contains(string(chartHTML), "1.000 W") {
		t.Fatalf("chart did not include configured max: %s", string(chartHTML))
	}
	if strings.Contains(string(chartHTML), "250 W") {
		t.Fatalf("chart unexpectedly used sample max instead of configured max: %s", string(chartHTML))
	}
}