package changes

import (
	"testing"
	"time"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
)

func TestCompareDailyNoMeaningfulChanges(t *testing.T) {
	previous := dailyBriefing(60, 70, 30, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
	current := dailyBriefing(61, 71, 35, at("2026-05-29T08:30:00Z"), nil, forecast.Indicators{})

	changes, err := CompareDaily(previous, current, testThresholds())
	if err != nil {
		t.Fatalf("CompareDaily() error = %v", err)
	}
	if len(changes) != 0 {
		t.Fatalf("changes = %#v, want none", changes)
	}
}

func TestCompareDailyTemperatureThreshold(t *testing.T) {
	previous := dailyBriefing(50, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
	current := dailyBriefing(58, 79, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})

	changes, err := CompareDaily(previous, current, testThresholds())
	if err != nil {
		t.Fatalf("CompareDaily() error = %v", err)
	}
	if countType(changes, "temperature_shift") != 2 {
		t.Fatalf("changes = %#v, want low and high temperature changes", changes)
	}
}

func TestCompareDailyPrecipTimingShift(t *testing.T) {
	previous := dailyBriefing(60, 70, 60, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
	current := dailyBriefing(60, 70, 60, at("2026-05-29T11:00:00Z"), nil, forecast.Indicators{})

	changes, err := CompareDaily(previous, current, testThresholds())
	if err != nil {
		t.Fatalf("CompareDaily() error = %v", err)
	}
	if countType(changes, "precip_timing_shift") != 1 {
		t.Fatalf("changes = %#v, want timing shift", changes)
	}
}

func TestCompareDailyAlertAddedAndRemoved(t *testing.T) {
	previous := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), []string{"Wind Advisory"}, forecast.Indicators{})
	current := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), []string{"Flood Watch"}, forecast.Indicators{})

	changes, err := CompareDaily(previous, current, testThresholds())
	if err != nil {
		t.Fatalf("CompareDaily() error = %v", err)
	}
	if countType(changes, "alert_added") != 1 || countType(changes, "alert_removed") != 1 {
		t.Fatalf("changes = %#v, want one alert added and one removed", changes)
	}
}

func TestCompareDailyIndicatorChange(t *testing.T) {
	previous := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
	current := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{Thunder: true})

	changes, err := CompareDaily(previous, current, testThresholds())
	if err != nil {
		t.Fatalf("CompareDaily() error = %v", err)
	}
	if countType(changes, "thunder_risk_change") != 1 {
		t.Fatalf("changes = %#v, want thunder risk change", changes)
	}
}

func dailyBriefing(low float64, high float64, precip float64, precipTime time.Time, alerts []string, indicators forecast.Indicators) briefing.Package {
	alertOverlaps := make([]forecast.AlertOverlap, 0, len(alerts))
	for _, alert := range alerts {
		alertOverlaps = append(alertOverlaps, forecast.AlertOverlap{Event: alert})
	}
	return briefing.Package{
		Daily: &briefing.Daily{
			BottomLine: briefing.BottomLine{
				Temperature: forecast.Range{Min: &low, Max: &high},
				MaxPrecipProbability: &forecast.TimedValue{
					Value: precip,
					Time:  precipTime,
				},
			},
			RelevantAlerts: alertOverlaps,
			Dayparts: []forecast.DaypartSummary{
				{Name: "morning", Indicators: indicators},
			},
		},
	}
}

func testThresholds() Thresholds {
	return Thresholds{
		TemperatureDegrees:       5,
		PrecipProbabilityPoints:  20,
		WindGustMilesPerHour:     10,
		PrecipTimingShiftMinutes: 120,
	}
}

func countType(changes []Change, changeType string) int {
	var count int
	for _, change := range changes {
		if change.Type == changeType {
			count++
		}
	}
	return count
}

func at(value string) time.Time {
	parsed, err := time.Parse(time.RFC3339, value)
	if err != nil {
		panic(err)
	}
	return parsed
}