package processor

import (
	"context"
	"testing"
	"time"

	"apskel-pos-be/internal/entities"

	"github.com/google/uuid"
	"github.com/stretchr/testify/require"
)

func jakarta(t *testing.T) *time.Location {
	t.Helper()
	loc, err := time.LoadLocation("Asia/Jakarta")
	require.NoError(t, err)
	return loc
}

func TestStartOfWeekLandsOnMonday(t *testing.T) {
	loc := jakarta(t)

	// 3 Aug 2026 is a Monday, so the whole week must collapse onto it
	monday := time.Date(2026, 8, 3, 0, 0, 0, 0, loc)

	for offset := 0; offset < 7; offset++ {
		day := monday.AddDate(0, 0, offset).Add(13 * time.Hour)

		got := startOfWeek(day)
		require.Equal(t, monday, got, "day %s should map to %s", day, monday)
		require.Equal(t, time.Monday, got.Weekday())
	}
}

func TestEndOfWeekLandsOnSunday(t *testing.T) {
	loc := jakarta(t)

	// Sunday 9 Aug 2026 closes the week that starts Monday 3 Aug
	got := endOfWeek(time.Date(2026, 8, 5, 9, 30, 0, 0, loc))

	require.Equal(t, time.Sunday, got.Weekday())
	require.Equal(t, 2026, got.Year())
	require.Equal(t, time.August, got.Month())
	require.Equal(t, 9, got.Day())
	require.Equal(t, 23, got.Hour())
	require.Equal(t, 59, got.Minute())
}

func TestBuildBudgetCutOffWidensToWholeWeeks(t *testing.T) {
	loc := jakarta(t)
	processor := &AnalyticsProcessorImpl{analyticsRepo: &analyticsRepositoryStub{}}

	// Saturday 1 Aug to Monday 31 Aug 2026: both ends fall mid-week
	from := time.Date(2026, 8, 1, 0, 0, 0, 0, loc)
	to := time.Date(2026, 8, 31, 23, 59, 59, 0, loc)

	budget, err := processor.buildBudgetCutOff(context.Background(), uuid.New(), nil, nil, from, to)
	require.NoError(t, err)

	// Reaches back into July and forward into September to keep weeks whole
	require.Equal(t, time.Monday, budget.CutOffFrom.Weekday())
	require.Equal(t, time.July, budget.CutOffFrom.Month())
	require.Equal(t, 27, budget.CutOffFrom.Day())
	require.Equal(t, time.Sunday, budget.CutOffTo.Weekday())
	require.Equal(t, time.September, budget.CutOffTo.Month())
	require.Equal(t, 6, budget.CutOffTo.Day())

	require.Len(t, budget.Weekly, 6)
	for _, week := range budget.Weekly {
		require.Equal(t, time.Monday, week.PeriodStart.Weekday())
		require.Equal(t, time.Sunday, week.PeriodEnd.Weekday())
	}

	// A week is filed under the month of its Monday, so the 27 Jul week counts as July
	require.Len(t, budget.Monthly, 2)
	require.Equal(t, "2026-07", budget.Monthly[0].Month)
	require.Equal(t, 1, budget.Monthly[0].WeekCount)
	require.Equal(t, "2026-08", budget.Monthly[1].Month)
	require.Equal(t, 5, budget.Monthly[1].WeekCount)
}

func TestBuildBudgetCutOffAppliesLimits(t *testing.T) {
	loc := jakarta(t)
	weekStart := time.Date(2026, 8, 3, 0, 0, 0, 0, loc)

	stub := &analyticsRepositoryStub{budgetCutOffWeeks: []*entities.BudgetCutOffWeek{
		{WeekStart: weekStart, Revenue: 10_000_000, OrderCount: 120},
	}}
	processor := &AnalyticsProcessorImpl{analyticsRepo: stub}

	budget, err := processor.buildBudgetCutOff(context.Background(), uuid.New(), nil, nil, weekStart, weekStart.AddDate(0, 0, 6))
	require.NoError(t, err)
	require.Len(t, budget.Weekly, 1)

	// 60 / 20 / 20 of the week's revenue
	week := budget.Weekly[0]
	require.Equal(t, float64(6_000_000), week.LimitPurchase)
	require.Equal(t, float64(2_000_000), week.LimitOwner)
	require.Equal(t, float64(2_000_000), week.LimitTeam)
	require.Equal(t, int64(120), week.OrderCount)

	// Totals mirror the single week
	require.Equal(t, week.Revenue, budget.Total.Revenue)
	require.Equal(t, week.LimitPurchase, budget.Total.LimitPurchase)
}

func TestBuildBudgetCutOffAccumulatesMonthlyFromWeeks(t *testing.T) {
	loc := jakarta(t)
	first := time.Date(2026, 8, 3, 0, 0, 0, 0, loc)

	stub := &analyticsRepositoryStub{budgetCutOffWeeks: []*entities.BudgetCutOffWeek{
		{WeekStart: first, Revenue: 10_000_000, OrderCount: 100},
		{WeekStart: first.AddDate(0, 0, 7), Revenue: 5_000_000, OrderCount: 60},
	}}
	processor := &AnalyticsProcessorImpl{analyticsRepo: stub}

	budget, err := processor.buildBudgetCutOff(context.Background(), uuid.New(), nil, nil, first, first.AddDate(0, 0, 9))
	require.NoError(t, err)

	require.Len(t, budget.Monthly, 1)
	month := budget.Monthly[0]
	require.Equal(t, "2026-08", month.Month)
	require.Equal(t, 2, month.WeekCount)
	require.Equal(t, float64(15_000_000), month.Revenue)
	require.Equal(t, int64(160), month.OrderCount)

	// The month limit is the accumulation of its weeks
	require.Equal(t, float64(9_000_000), month.LimitPurchase)
	require.Equal(t, budget.Weekly[0].LimitPurchase+budget.Weekly[1].LimitPurchase, month.LimitPurchase)
}

func TestBuildBudgetCutOffEmitsWeeksWithoutSales(t *testing.T) {
	loc := jakarta(t)
	first := time.Date(2026, 8, 3, 0, 0, 0, 0, loc)

	// Only the third week has sales; the two quiet weeks must still be reported
	stub := &analyticsRepositoryStub{budgetCutOffWeeks: []*entities.BudgetCutOffWeek{
		{WeekStart: first.AddDate(0, 0, 14), Revenue: 4_000_000, OrderCount: 40},
	}}
	processor := &AnalyticsProcessorImpl{analyticsRepo: stub}

	budget, err := processor.buildBudgetCutOff(context.Background(), uuid.New(), nil, nil, first, first.AddDate(0, 0, 16))
	require.NoError(t, err)

	require.Len(t, budget.Weekly, 3)
	require.Zero(t, budget.Weekly[0].Revenue)
	require.Zero(t, budget.Weekly[0].LimitPurchase)
	require.Zero(t, budget.Weekly[1].Revenue)
	require.Equal(t, float64(4_000_000), budget.Weekly[2].Revenue)
	require.Equal(t, float64(4_000_000), budget.Total.Revenue)
}