package repository

import (
	"context"
	"errors"
	"time"

	"gorm.io/gorm"

	"github.com/kennethcheng/fuellog-api/internal/model"
	"github.com/kennethcheng/fuellog-api/pkg/apperror"
)

// RefuelRecordRepository 加油记录表的数据访问接口。
type RefuelRecordRepository interface {
	Create(ctx context.Context, r *model.RefuelRecord) error
	Get(ctx context.Context, id uint64) (*model.RefuelRecord, error)
	Update(ctx context.Context, r *model.RefuelRecord) error
	Delete(ctx context.Context, id uint64) error
	// List 返回指定车辆的加油记录,按 refuel_time DESC 排序。
	// 支持可选时间窗口。
	ListByVehicle(ctx context.Context, vehicleID uint64, start, end *time.Time) ([]model.RefuelRecord, error)
	// PrevFullRefuel 返回指定车辆在 time 之前最近一次 is_full=true 的记录。
	// 用于计算百公里油耗。
	PrevFullRefuel(ctx context.Context, vehicleID uint64, before time.Time) (*model.RefuelRecord, error)
}

func NewRefuelRecordRepository(g *gorm.DB) RefuelRecordRepository {
	return &refuelRepo{g: g}
}

type refuelRepo struct{ g *gorm.DB }

func (r *refuelRepo) Create(ctx context.Context, rec *model.RefuelRecord) error {
	if err := r.g.WithContext(ctx).Create(rec).Error; err != nil {
		return apperror.Wrap(apperror.CodeInternal, "创建加油记录失败", err)
	}
	return nil
}

func (r *refuelRepo) Get(ctx context.Context, id uint64) (*model.RefuelRecord, error) {
	var rec model.RefuelRecord
	if err := r.g.WithContext(ctx).First(&rec, id).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, apperror.New(apperror.CodeNotFound, "加油记录不存在")
		}
		return nil, apperror.Wrap(apperror.CodeInternal, "查询加油记录失败", err)
	}
	return &rec, nil
}

func (r *refuelRepo) Update(ctx context.Context, rec *model.RefuelRecord) error {
	res := r.g.WithContext(ctx).Save(rec)
	if res.Error != nil {
		return apperror.Wrap(apperror.CodeInternal, "更新加油记录失败", res.Error)
	}
	if res.RowsAffected == 0 {
		return apperror.New(apperror.CodeNotFound, "加油记录不存在")
	}
	return nil
}

func (r *refuelRepo) Delete(ctx context.Context, id uint64) error {
	res := r.g.WithContext(ctx).Delete(&model.RefuelRecord{}, id)
	if res.Error != nil {
		return apperror.Wrap(apperror.CodeInternal, "删除加油记录失败", res.Error)
	}
	if res.RowsAffected == 0 {
		return apperror.New(apperror.CodeNotFound, "加油记录不存在")
	}
	return nil
}

func (r *refuelRepo) ListByVehicle(ctx context.Context, vehicleID uint64, start, end *time.Time) ([]model.RefuelRecord, error) {
	q := r.g.WithContext(ctx).Where("vehicle_id = ?", vehicleID)
	if start != nil {
		q = q.Where("refuel_time >= ?", *start)
	}
	if end != nil {
		q = q.Where("refuel_time <= ?", *end)
	}
	var out []model.RefuelRecord
	if err := q.Order("refuel_time DESC, id DESC").Find(&out).Error; err != nil {
		return nil, apperror.Wrap(apperror.CodeInternal, "查询加油记录列表失败", err)
	}
	return out, nil
}

func (r *refuelRepo) PrevFullRefuel(ctx context.Context, vehicleID uint64, before time.Time) (*model.RefuelRecord, error) {
	var rec model.RefuelRecord
	err := r.g.WithContext(ctx).
		Where("vehicle_id = ? AND is_full = ? AND refuel_time < ?", vehicleID, true, before).
		Order("refuel_time DESC, id DESC").
		First(&rec).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, apperror.New(apperror.CodeNotFound, "此前没有加满油记录")
		}
		return nil, apperror.Wrap(apperror.CodeInternal, "查询前次加满记录失败", err)
	}
	return &rec, nil
}