package order

import (
	"context"
	"testing"

	"github.com/perfect-panel/server/internal/model/promo"
	"github.com/perfect-panel/server/internal/svc"
	"github.com/perfect-panel/server/internal/types"
	"gorm.io/gorm"
)

type fakePromoModel struct {
	rules            []*promo.RuleWithPrice
	lastSubscribeID  int64
	lastQuantity     int64
	requireQuantity  int64
	quantityMismatch []*promo.RuleWithPrice
}

func (m *fakePromoModel) QueryEligibleRules(_ context.Context, subscribeID int64, quantity int64) ([]*promo.RuleWithPrice, error) {
	m.lastSubscribeID = subscribeID
	m.lastQuantity = quantity
	if m.requireQuantity > 0 && quantity != m.requireQuantity {
		return m.quantityMismatch, nil
	}
	return m.rules, nil
}

func (m *fakePromoModel) InsertUsage(context.Context, *promo.Usage, ...*gorm.DB) error {
	return nil
}

func TestCalculatePurchasePricePromoSkipsPercentDiscount(t *testing.T) {
	svcCtx := &svc.ServiceContext{
		DB: &gorm.DB{},
		PromoModel: &fakePromoModel{rules: []*promo.RuleWithPrice{
			{
				Rule: promo.Rule{
					Id:      9,
					Name:    "campaign",
					Type:    promo.RuleTypeCampaign,
					Enabled: true,
				},
				PromoPrice: 600,
			},
		}},
	}

	result, err := calculatePurchasePrice(
		context.Background(),
		svcCtx,
		1,
		2,
		1000,
		3,
		[]types.SubscribeDiscount{{Quantity: 3, Discount: 50}},
		true,
		true,
	)
	if err != nil {
		t.Fatalf("calculatePurchasePrice returned error: %v", err)
	}

	if result.OriginalPrice != 3000 {
		t.Fatalf("OriginalPrice = %d, want 3000", result.OriginalPrice)
	}
	if result.PayableBase != 1800 {
		t.Fatalf("PayableBase = %d, want 1800", result.PayableBase)
	}
	if result.DiscountAmount != 0 {
		t.Fatalf("DiscountAmount = %d, want 0", result.DiscountAmount)
	}
	if result.PromoRuleId != 9 {
		t.Fatalf("PromoRuleId = %d, want 9", result.PromoRuleId)
	}
	if result.PromoDiscount != 1200 {
		t.Fatalf("PromoDiscount = %d, want 1200", result.PromoDiscount)
	}
}

func TestCalculatePurchasePriceIgnoresInvalidPromoPrice(t *testing.T) {
	svcCtx := &svc.ServiceContext{
		DB: &gorm.DB{},
		PromoModel: &fakePromoModel{rules: []*promo.RuleWithPrice{
			{
				Rule: promo.Rule{
					Id:      10,
					Name:    "invalid campaign",
					Type:    promo.RuleTypeCampaign,
					Enabled: true,
				},
				PromoPrice: 1000,
			},
		}},
	}

	result, err := calculatePurchasePrice(
		context.Background(),
		svcCtx,
		1,
		2,
		1000,
		3,
		[]types.SubscribeDiscount{{Quantity: 3, Discount: 50}},
		true,
		true,
	)
	if err != nil {
		t.Fatalf("calculatePurchasePrice returned error: %v", err)
	}

	if result.PayableBase != 1500 {
		t.Fatalf("PayableBase = %d, want 1500", result.PayableBase)
	}
	if result.DiscountAmount != 1500 {
		t.Fatalf("DiscountAmount = %d, want 1500", result.DiscountAmount)
	}
	if result.PromoRuleId != 0 || result.PromoDiscount != 0 {
		t.Fatalf("promo fields = (%d, %d), want (0, 0)", result.PromoRuleId, result.PromoDiscount)
	}
}

func TestCalculatePurchasePricePassesQuantityToPromoEvaluation(t *testing.T) {
	promoModel := &fakePromoModel{
		requireQuantity: 6,
		rules: []*promo.RuleWithPrice{
			{
				Rule: promo.Rule{
					Id:      11,
					Name:    "quantity campaign",
					Type:    promo.RuleTypeCampaign,
					Enabled: true,
				},
				PromoPrice: 500,
			},
		},
	}
	svcCtx := &svc.ServiceContext{
		DB:         &gorm.DB{},
		PromoModel: promoModel,
	}

	result, err := calculatePurchasePrice(
		context.Background(),
		svcCtx,
		1,
		2,
		1000,
		6,
		[]types.SubscribeDiscount{{Quantity: 6, Discount: 80}},
		true,
		true,
	)
	if err != nil {
		t.Fatalf("calculatePurchasePrice returned error: %v", err)
	}

	if promoModel.lastSubscribeID != 2 {
		t.Fatalf("lastSubscribeID = %d, want 2", promoModel.lastSubscribeID)
	}
	if promoModel.lastQuantity != 6 {
		t.Fatalf("lastQuantity = %d, want 6", promoModel.lastQuantity)
	}
	if result.PayableBase != 3000 {
		t.Fatalf("PayableBase = %d, want 3000", result.PayableBase)
	}
	if result.PromoRuleId != 11 {
		t.Fatalf("PromoRuleId = %d, want 11", result.PromoRuleId)
	}
}