package service

import (
	"fmt"
	"testing"
	"time"

	"github.com/glebarez/sqlite"
	"github.com/stretchr/testify/require"
	"gorm.io/gorm"
	"wails-app/internal/dao"
	"wails-app/internal/global"
)

func setupFeeTest(t *testing.T) {
	t.Helper()
	dsn := fmt.Sprintf("file:fee-%d?mode=memory&cache=shared", time.Now().UnixNano())
	db, err := gorm.Open(sqlite.Open(dsn), &gorm.Config{})
	require.NoError(t, err)
	sqlDB, err := db.DB()
	require.NoError(t, err)
	t.Cleanup(func() {
		_ = sqlDB.Close()
		if global.GVA_DB == db {
			global.GVA_DB = nil
		}
	})
	global.GVA_DB = db
	require.NoError(t, db.AutoMigrate(&dao.Vehicle{}, &dao.VehicleType{}, &dao.Owner{}, &dao.FeeConfig{}))
}

func seedVehicle(t *testing.T, typeID uint, plate string) *dao.Vehicle {
	t.Helper()
	vehicle := dao.Vehicle{PlateNumber: plate, VehicleTypeID: typeID}
	require.NoError(t, global.GVA_DB.Create(&vehicle).Error)
	return &vehicle
}

// seedConfig 创建收费配置：免费 15 分钟，起步 5 元，每 30 分钟 3 元。
func seedConfig(t *testing.T, typeID uint, mut func(*dao.FeeConfig)) {
	t.Helper()
	config := dao.FeeConfig{
		VehicleTypeID: typeID, StartTime: 15, StartFee: 5,
		UnitTime: 30, UnitFee: 3, DailyMaxFee: 30, VIPDiscount: 1.0,
	}
	if mut != nil {
		mut(&config)
	}
	require.NoError(t, global.GVA_DB.Create(&config).Error)
}

func TestCalculateFeeRejectsMissingConfig(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 99, "FEE-001")

	fee, err := CalculateFee(vehicle, 60)
	require.ErrorIs(t, err, ErrFeeConfigNotFound)
	require.Zero(t, fee)
}

func TestCalculateFeeRejectsInvalidUnitTime(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 99, "FEE-002")
	seedConfig(t, 99, func(c *dao.FeeConfig) { c.UnitTime = 0 })

	fee, err := CalculateFee(vehicle, 60)
	require.ErrorIs(t, err, ErrFeeConfigInvalid)
	require.Zero(t, fee)
}

func TestCalculateFeeFreePeriodAndNormalBilling(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 1, "FEE-003")
	seedConfig(t, 1, nil)

	// 免费时长内
	fee, err := CalculateFee(vehicle, 15)
	require.NoError(t, err)
	require.Zero(t, fee)

	// 30 分钟：5 + ceil(15/30)*3 = 8
	fee, err = CalculateFee(vehicle, 30)
	require.NoError(t, err)
	require.Equal(t, 8.0, fee)

	// 45 分钟：5 + ceil(30/30)*3 = 8（免费 15 后正好 1 个单位）
	fee, err = CalculateFee(vehicle, 45)
	require.NoError(t, err)
	require.Equal(t, 8.0, fee)

	// 46 分钟：5 + ceil(31/30)*3 = 11（不足一个单位按一个单位）
	fee, err = CalculateFee(vehicle, 46)
	require.NoError(t, err)
	require.Equal(t, 11.0, fee)
}

func TestCalculateFeeDailyCapWithinOneDay(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 1, "FEE-004")
	seedConfig(t, 1, nil)

	// 10 小时：5 + ceil(585/30)*3 = 65 → 封顶 30
	fee, err := CalculateFee(vehicle, 600)
	require.NoError(t, err)
	require.Equal(t, 30.0, fee)
}

func TestCalculateFeeMultiDayCapAccumulates(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 1, "FEE-005")
	seedConfig(t, 1, nil)

	// 26 小时（跨 2 天）：原始 5 + ceil(1545/30)*3 = 161 → 封顶 2×30 = 60
	fee, err := CalculateFee(vehicle, 1560)
	require.NoError(t, err)
	require.Equal(t, 60.0, fee)

	// 3 天整：封顶 3×30 = 90
	fee, err = CalculateFee(vehicle, 3*1440)
	require.NoError(t, err)
	require.Equal(t, 90.0, fee)
}

func TestCalculateFeeNoCapMultiDayChargesFull(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 1, "FEE-006")
	seedConfig(t, 1, func(c *dao.FeeConfig) { c.DailyMaxFee = 0 })

	// 2 天：5 + ceil(2865/30)*3 = 5 + 288 = 293（无封顶）
	fee, err := CalculateFee(vehicle, 2*1440)
	require.NoError(t, err)
	require.Equal(t, 293.0, fee)
}

func TestCalculateFeeZeroConfigMeansExplicitFree(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 1, "FEE-007")
	seedConfig(t, 1, func(c *dao.FeeConfig) {
		c.StartTime, c.StartFee, c.UnitFee, c.DailyMaxFee = 0, 0, 0, 0
	})

	fee, err := CalculateFee(vehicle, 600)
	require.NoError(t, err)
	require.Zero(t, fee)
}

func TestCalculateFeeVIPFree(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 1, "FEE-008")
	seedConfig(t, 1, func(c *dao.FeeConfig) { c.IsVIPFree = true })

	future := time.Now().Add(24 * time.Hour)
	require.NoError(t, global.GVA_DB.Create(&dao.Owner{
		OwnerName: "VIP车", IsVip: true, VipExpireTime: future,
	}).Error)
	require.NoError(t, global.GVA_DB.Model(vehicle).Update("owner_id", 1).Error)

	fee, err := CalculateFee(vehicle, 120)
	require.NoError(t, err)
	require.Zero(t, fee)
}

func TestCalculateFeeVIPDiscount(t *testing.T) {
	setupFeeTest(t)
	vehicle := seedVehicle(t, 1, "FEE-009")
	seedConfig(t, 1, func(c *dao.FeeConfig) { c.VIPDiscount = 0.8 })

	future := time.Now().Add(24 * time.Hour)
	require.NoError(t, global.GVA_DB.Create(&dao.Owner{
		OwnerName: "VIP车", IsVip: true, VipExpireTime: future,
	}).Error)
	require.NoError(t, global.GVA_DB.Model(vehicle).Update("owner_id", 1).Error)

	fee, err := CalculateFee(vehicle, 120)
	require.NoError(t, err)
	// 原始：5 + ceil(105/30)*3 = 17 → 封顶 30 以内 → ×0.8 = 13.6
	require.InDelta(t, 13.6, fee, 0.001)
}