package templates

import "testing"

// TestEventTextColorKeepsReadableColorsUnchanged covers the reported bug:
// picking white (or any other very light color) for a calendar made its
// events unreadable in the month view, since monthDayCell used the same
// color for both the (barely tinted) background and the text. Light
// colors must be darkened for text use; colors that were already fine
// must render exactly as chosen.
func TestEventTextColorKeepsReadableColorsUnchanged(t *testing.T) {
	for _, c := range []string{"#3b82f6", "#ec4899", "#10b981", "#000000"} {
		if got := eventTextColor(c); got != c {
			t.Errorf("eventTextColor(%s) = %s, want unchanged", c, got)
		}
	}
}

func TestEventTextColorDarkensLightColors(t *testing.T) {
	for _, c := range []string{"#ffffff", "#ffff00", "#f0f0f0", "#fefefe"} {
		got := eventTextColor(c)
		if got == c {
			t.Errorf("eventTextColor(%s) = %s, want darkened for readability", c, got)
		}
		r, g, b, ok := parseHexColor(got)
		if !ok {
			t.Fatalf("eventTextColor(%s) returned unparseable color %s", c, got)
		}
		luminance := 0.299*float64(r) + 0.587*float64(g) + 0.114*float64(b)
		if luminance > 170 {
			t.Errorf("eventTextColor(%s) = %s still too light (luminance %.1f)", c, got, luminance)
		}
	}
}

// TestEventRangeText pins the human-readable "When" strings shown on the
// event detail view so any change to date formatting is intentional.
func TestEventRangeText(t *testing.T) {
	cases := []struct {
		name string
		form EventFormData
		want string
	}{
		{
			name: "single allday date",
			form: EventFormData{AllDay: true, StartDate: "2026-08-05", EndDate: "2026-08-05"},
			want: "August 5, 2026",
		},
		{
			name: "all-day multi-day same month",
			form: EventFormData{AllDay: true, StartDate: "2026-08-05", EndDate: "2026-08-07"},
			want: "Aug 5 – 7, 2026",
		},
		{
			name: "all-day multi-day different months",
			form: EventFormData{AllDay: true, StartDate: "2026-08-30", EndDate: "2026-09-02"},
			want: "Aug 30, 2026 – Sep 2, 2026",
		},
		{
			name: "timed same day",
			form: EventFormData{AllDay: false, StartDate: "2026-08-05", StartTime: "14:00", EndDate: "2026-08-05", EndTime: "15:00"},
			want: "August 5, 2026, 14:00 – 15:00",
		},
		{
			name: "timed different days same month",
			form: EventFormData{AllDay: false, StartDate: "2026-08-05", StartTime: "23:30", EndDate: "2026-08-06", EndTime: "01:00"},
			want: "Aug 5, 23:30 – 01:00, 2026",
		},
		{
			name: "timed different months",
			form: EventFormData{AllDay: false, StartDate: "2026-08-31", StartTime: "10:00", EndDate: "2026-09-01", EndTime: "11:00"},
			want: "Aug 31, 2026, 10:00 – Sep 1, 2026, 11:00",
		},
	}
	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			if got := eventRangeText(c.form); got != c.want {
				t.Errorf("eventRangeText(%+v) = %q, want %q", c.form, got, c.want)
			}
		})
	}
}

func TestEventTextColorFallsBackForInvalidInput(t *testing.T) {
	if got := eventTextColor(""); got != colorOrDefault("") {
		t.Errorf("eventTextColor(\"\") = %s, want the same default colorOrDefault returns", got)
	}
	if got := eventTextColor("not-a-color"); got != "not-a-color" {
		t.Errorf("eventTextColor(unparseable) = %s, want passed through unchanged", got)
	}
}