package handlers

import (
	"testing"
	"time"

	"task-dashboard/internal/models"
)

func multiDayEvent(startISO, endISO string) models.TimelineItem {
	start, _ := time.Parse(time.RFC3339, startISO)
	end, _ := time.Parse(time.RFC3339, endISO)
	return models.TimelineItem{
		ID:      "evt-1",
		Title:   "Offsite",
		Type:    models.TimelineItemTypeEvent,
		Time:    start,
		EndTime: &end,
	}
}

func TestIsMultiDayEvent_SameDayTimedEvent_False(t *testing.T) {
	item := multiDayEvent("2026-07-13T10:00:00Z", "2026-07-13T11:00:00Z")
	if isMultiDayEvent(item) {
		t.Error("expected same-day timed event to not be multi-day")
	}
}

func TestIsMultiDayEvent_SpansMultipleDays_True(t *testing.T) {
	item := multiDayEvent("2026-07-13T17:35:00Z", "2026-07-30T22:30:00Z")
	if !isMultiDayEvent(item) {
		t.Error("expected event spanning multiple days to be multi-day")
	}
}

func TestIsMultiDayEvent_NonEventType_AlwaysFalse(t *testing.T) {
	start, _ := time.Parse(time.RFC3339, "2026-07-13T10:00:00Z")
	end, _ := time.Parse(time.RFC3339, "2026-07-30T22:30:00Z")
	item := models.TimelineItem{ID: "t1", Type: models.TimelineItemTypeTask, Time: start, EndTime: &end}
	if isMultiDayEvent(item) {
		t.Error("expected non-event type to never be considered multi-day, regardless of span")
	}
}

func TestIsMultiDayEvent_NoEndTime_False(t *testing.T) {
	start, _ := time.Parse(time.RFC3339, "2026-07-13T10:00:00Z")
	item := models.TimelineItem{ID: "e1", Type: models.TimelineItemTypeEvent, Time: start}
	if isMultiDayEvent(item) {
		t.Error("expected event with nil EndTime to not be multi-day")
	}
}

func TestMultiDayVariant_StartDay_ReturnsStarts(t *testing.T) {
	item := multiDayEvent("2026-07-13T17:35:00Z", "2026-07-30T22:30:00Z")
	renderDay, _ := time.Parse(time.RFC3339, "2026-07-13T00:00:00Z")
	if got := multiDayVariant(item, renderDay); got != "starts" {
		t.Errorf("variant = %q, want %q", got, "starts")
	}
}

func TestMultiDayVariant_EndDay_ReturnsEnds(t *testing.T) {
	item := multiDayEvent("2026-07-13T17:35:00Z", "2026-07-30T22:30:00Z")
	renderDay, _ := time.Parse(time.RFC3339, "2026-07-30T00:00:00Z")
	if got := multiDayVariant(item, renderDay); got != "ends" {
		t.Errorf("variant = %q, want %q", got, "ends")
	}
}

func TestMultiDayVariant_MiddleDay_ReturnsSpans(t *testing.T) {
	item := multiDayEvent("2026-07-13T17:35:00Z", "2026-07-30T22:30:00Z")
	renderDay, _ := time.Parse(time.RFC3339, "2026-07-20T00:00:00Z")
	if got := multiDayVariant(item, renderDay); got != "spans" {
		t.Errorf("variant = %q, want %q", got, "spans")
	}
}

func TestMultiDayVariant_DayOutsideSpan_ReturnsEmpty(t *testing.T) {
	item := multiDayEvent("2026-07-13T17:35:00Z", "2026-07-30T22:30:00Z")
	renderDay, _ := time.Parse(time.RFC3339, "2026-08-01T00:00:00Z")
	if got := multiDayVariant(item, renderDay); got != "" {
		t.Errorf("variant = %q, want empty", got)
	}
}