package processor

import (
	"testing"

	"github.com/stretchr/testify/assert"

	"apskel-pos-be/internal/entities"
	"apskel-pos-be/internal/models"
)

// 1 EnakPoint per Rp 100 and 1 EnakCoin per Rp 25.000, as in the F1 example.
func prdEarningSettings() models.OutletLoyaltySettings {
	return models.OutletLoyaltySettings{
		Point: models.LoyaltyEarnSettings{Enabled: true, EarnPerAmount: 100, EarnValue: 1},
		Coin:  models.LoyaltyEarnSettings{Enabled: true, EarnPerAmount: 25000, EarnValue: 1},
	}
}

func TestCalculateEarning_PRDExample(t *testing.T) {
	// Subtotal after discount Rp 87.500, paid in full in cash.
	order := &entities.Order{Subtotal: 97500, DiscountAmount: 10000, TaxAmount: 9625, TotalAmount: 97125}

	got := CalculateEarning(order, 0, prdEarningSettings())
	assert.Equal(t, 87500.0, got.Basis)
	assert.Equal(t, int64(875), got.Point.Amount)
	assert.Equal(t, int64(3), got.Coin.Amount)

	// Rp 20.000 of it paid with EnakPoint earns nothing.
	got = CalculateEarning(order, 20000, prdEarningSettings())
	assert.Equal(t, 67500.0, got.Basis)
	assert.Equal(t, int64(675), got.Point.Amount)
	assert.Equal(t, int64(2), got.Coin.Amount)
}

func TestCalculateEarning_TaxIsNotPartOfTheBasis(t *testing.T) {
	withoutTax := &entities.Order{Subtotal: 50000}
	withTax := &entities.Order{Subtotal: 50000, TaxAmount: 5500, TotalAmount: 55500}
	assert.Equal(t, CalculateEarning(withoutTax, 0, prdEarningSettings()), CalculateEarning(withTax, 0, prdEarningSettings()))
	assert.Equal(t, int64(500), CalculateEarning(withTax, 0, prdEarningSettings()).Point.Amount)
}

func TestCalculateEarning_BelowMinimum(t *testing.T) {
	s := prdEarningSettings()
	s.Point.MinOrderAmount = 50000

	assert.Equal(t, int64(0), CalculateEarning(&entities.Order{Subtotal: 49999}, 0, s).Point.Amount)
	assert.Equal(t, int64(500), CalculateEarning(&entities.Order{Subtotal: 50000}, 0, s).Point.Amount, "the minimum itself earns")
	// The minimum applies to the basis, after discount and EnakPoint.
	assert.Equal(t, int64(0), CalculateEarning(&entities.Order{Subtotal: 60000}, 15000, s).Point.Amount)
	// Coin has its own minimum.
	assert.Equal(t, int64(1), CalculateEarning(&entities.Order{Subtotal: 49999}, 0, s).Coin.Amount)
}

func TestCalculateEarning_MaxPerOrder(t *testing.T) {
	s := prdEarningSettings()
	max := int64(300)
	s.Point.MaxPerOrder = &max

	got := CalculateEarning(&entities.Order{Subtotal: 87500}, 0, s)
	assert.Equal(t, int64(300), got.Point.Amount)
	assert.True(t, got.Point.Capped)
	assert.Equal(t, int64(300), got.Metadata(got.Point)["max_per_order"])

	got = CalculateEarning(&entities.Order{Subtotal: 20000}, 0, s)
	assert.Equal(t, int64(200), got.Point.Amount)
	assert.False(t, got.Point.Capped)

	zero := int64(0)
	s.Point.MaxPerOrder = &zero
	assert.Equal(t, int64(0), CalculateEarning(&entities.Order{Subtotal: 87500}, 0, s).Point.Amount)
}

func TestCalculateEarning_DisabledEarnsNothing(t *testing.T) {
	s := prdEarningSettings()
	s.Point.Enabled = false
	got := CalculateEarning(&entities.Order{Subtotal: 87500}, 0, s)
	assert.Equal(t, int64(0), got.Point.Amount)
	assert.Equal(t, int64(3), got.Coin.Amount, "each currency is switched on its own")

	s.Coin.Enabled = false
	got = CalculateEarning(&entities.Order{Subtotal: 87500}, 0, s)
	assert.Equal(t, int64(0), got.Coin.Amount)
	assert.Equal(t, 87500.0, got.Basis, "the basis is still reported")

	// The defaults of an outlet that never set anything earn nothing.
	var defaults models.OutletLoyaltySettings
	loadLoyaltyFields(outletLoyaltyFields(&defaults), nil, "test")
	got = CalculateEarning(&entities.Order{Subtotal: 87500}, 0, defaults)
	assert.Equal(t, int64(0), got.Point.Amount)
	assert.Equal(t, int64(0), got.Coin.Amount)
}

func TestCalculateEarning_EdgeCases(t *testing.T) {
	s := prdEarningSettings()

	// floor, not round.
	assert.Equal(t, int64(875), CalculateEarning(&entities.Order{Subtotal: 87599.99}, 0, s).Point.Amount)
	// Values float64 cannot hold exactly do not lose a point: computed in float64 this
	// basis divides to 4956.999…, which a naive floor turns into 4956.
	per250 := prdEarningSettings()
	per250.Point.EarnPerAmount = 250
	assert.Equal(t, int64(4957), CalculateEarning(&entities.Order{Subtotal: 1240155.48, DiscountAmount: 749.11}, 156.37, per250).Point.Amount)
	// Paying more with EnakPoint than the basis leaves nothing, never a negative amount.
	got := CalculateEarning(&entities.Order{Subtotal: 10000}, 15000, s)
	assert.Equal(t, 0.0, got.Basis)
	assert.Equal(t, int64(0), got.Point.Amount)
	// earn_value multiplies.
	s.Point.EarnValue = 5
	assert.Equal(t, int64(4375), CalculateEarning(&entities.Order{Subtotal: 87500}, 0, s).Point.Amount)
	// A zero earn_value earns nothing even when enabled.
	s.Point.EarnValue = 0
	assert.Equal(t, int64(0), CalculateEarning(&entities.Order{Subtotal: 87500}, 0, s).Point.Amount)
}

func TestCalculateEarning_MetadataSnapshot(t *testing.T) {
	got := CalculateEarning(&entities.Order{Subtotal: 87500}, 0, prdEarningSettings())
	assert.Equal(t, entities.Metadata{
		"basis": 87500.0, "earn_per_amount": int64(100), "earn_value": int64(1), "min_order_amount": int64(0), "capped": false,
	}, got.Metadata(got.Point))
}