package service

import (
	"context"
	"errors"
	"fmt"
	"time"

	"gorm.io/gorm"

	smokemodel "wx_service/internal/smoke/model"
)

var (
	ErrSmokeLogNotFound = errors.New("smoke log not found")
)

type SmokeLogService struct {
	db *gorm.DB
}

func NewSmokeLogService(db *gorm.DB) *SmokeLogService {
	return &SmokeLogService{db: db}
}

type CreateSmokeLogRequest struct {
	SmokeTime *time.Time
	SmokeAt   *time.Time
	Remark    string
	Level     int64
	Num       int
}

func (s *SmokeLogService) Create(ctx context.Context, uid int, req CreateSmokeLogRequest) (*smokemodel.SmokeLog, error) {
	now := time.Now().Unix()
	createTime := now
	updateTime := now

	level := req.Level
	if level <= 0 {
		level = 1
	}
	num := req.Num
	if num <= 0 {
		num = 1
	}

	smokeAt := req.SmokeAt

	// smokeTime 用于“按天筛选”；如果传了 smokeAt，建议用其日期部分回填 smokeTime，避免出现不一致。
	smokeTime := req.SmokeTime
	if smokeAt != nil {
		day := time.Date(smokeAt.Year(), smokeAt.Month(), smokeAt.Day(), 0, 0, 0, 0, smokeAt.Location())
		smokeTime = &day
	}
	if smokeTime == nil {
		today := time.Now()
		startOfDay := time.Date(today.Year(), today.Month(), today.Day(), 0, 0, 0, 0, today.Location())
		smokeTime = &startOfDay
	}

	record := smokemodel.SmokeLog{
		UID:        uid,
		SmokeTime:  smokeTime,
		SmokeAt:    smokeAt,
		Remark:     req.Remark,
		CreateTime: &createTime,
		UpdateTime: &updateTime,
		Level:      level,
		Num:        num,
	}

	if err := s.db.WithContext(ctx).Create(&record).Error; err != nil {
		return nil, fmt.Errorf("create smoke log: %w", err)
	}
	return &record, nil
}

func (s *SmokeLogService) GetByID(ctx context.Context, uid int, id int) (*smokemodel.SmokeLog, error) {
	var record smokemodel.SmokeLog
	err := s.db.WithContext(ctx).
		Where("id = ? AND uid = ? AND (deletetime IS NULL OR deletetime = 0)", id, uid).
		First(&record).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrSmokeLogNotFound
		}
		return nil, fmt.Errorf("load smoke log: %w", err)
	}
	return &record, nil
}

type ListSmokeLogsRequest struct {
	Page     int
	PageSize int
	Start    *time.Time
	End      *time.Time
}

type ListSmokeLogsResult struct {
	Items    []smokemodel.SmokeLog
	Total    int64
	Page     int
	PageSize int
}

func (s *SmokeLogService) List(ctx context.Context, uid int, req ListSmokeLogsRequest) (ListSmokeLogsResult, error) {
	page := req.Page
	if page <= 0 {
		page = 1
	}
	pageSize := req.PageSize
	if pageSize <= 0 {
		pageSize = 20
	}
	if pageSize > 200 {
		pageSize = 200
	}

	tx := s.db.WithContext(ctx).Model(&smokemodel.SmokeLog{}).
		Where("uid = ? AND (deletetime IS NULL OR deletetime = 0)", uid)

	if req.Start != nil {
		tx = tx.Where("smoke_time >= ?", req.Start.Format("2006-01-02"))
	}
	if req.End != nil {
		tx = tx.Where("smoke_time <= ?", req.End.Format("2006-01-02"))
	}

	var total int64
	if err := tx.Count(&total).Error; err != nil {
		return ListSmokeLogsResult{}, fmt.Errorf("count smoke logs: %w", err)
	}

	var items []smokemodel.SmokeLog
	offset := (page - 1) * pageSize
	if err := tx.
		Order("smoke_time DESC").
		Order("id DESC").
		Limit(pageSize).
		Offset(offset).
		Find(&items).Error; err != nil {
		return ListSmokeLogsResult{}, fmt.Errorf("list smoke logs: %w", err)
	}

	return ListSmokeLogsResult{
		Items:    items,
		Total:    total,
		Page:     page,
		PageSize: pageSize,
	}, nil
}

type UpdateSmokeLogRequest struct {
	// SmokeTimeProvided 用于区分：
	// - false：前端没传 smoke_time（不修改）
	// - true：前端传了 smoke_time（可以设置为具体日期，也可以清空为 NULL）
	SmokeTimeProvided bool
	SmokeTime         *time.Time
	// SmokeAtProvided 用于区分：
	// - false：前端没传 smoke_at（不修改）
	// - true：前端传了 smoke_at（可以设置为具体时间，也可以清空为 NULL）
	SmokeAtProvided bool
	SmokeAt         *time.Time
	Remark            *string
	Level             *int64
	Num               *int
}

func (s *SmokeLogService) Update(ctx context.Context, uid int, id int, req UpdateSmokeLogRequest) (*smokemodel.SmokeLog, error) {
	record, err := s.GetByID(ctx, uid, id)
	if err != nil {
		return nil, err
	}

	updates := map[string]interface{}{}
	if req.SmokeTimeProvided {
		updates["smoke_time"] = req.SmokeTime
	}
	if req.SmokeAtProvided {
		updates["smoke_at"] = req.SmokeAt
		if req.SmokeAt != nil {
			day := time.Date(req.SmokeAt.Year(), req.SmokeAt.Month(), req.SmokeAt.Day(), 0, 0, 0, 0, req.SmokeAt.Location())
			updates["smoke_time"] = &day
		}
	}
	if req.Remark != nil {
		updates["remark"] = *req.Remark
	}
	if req.Level != nil {
		if *req.Level <= 0 {
			updates["level"] = int64(1)
		} else {
			updates["level"] = *req.Level
		}
	}
	if req.Num != nil {
		if *req.Num <= 0 {
			updates["num"] = 1
		} else {
			updates["num"] = *req.Num
		}
	}

	now := time.Now().Unix()
	updates["updatetime"] = now

	if len(updates) == 1 {
		return record, nil
	}

	if err := s.db.WithContext(ctx).
		Model(&smokemodel.SmokeLog{}).
		Where("id = ? AND uid = ?", id, uid).
		Updates(updates).Error; err != nil {
		return nil, fmt.Errorf("update smoke log: %w", err)
	}

	return s.GetByID(ctx, uid, id)
}

func (s *SmokeLogService) Delete(ctx context.Context, uid int, id int) error {
	now := time.Now().Unix()
	result := s.db.WithContext(ctx).
		Model(&smokemodel.SmokeLog{}).
		Where("id = ? AND uid = ? AND (deletetime IS NULL OR deletetime = 0)", id, uid).
		Updates(map[string]interface{}{
			"deletetime": now,
			"updatetime": now,
		})
	if result.Error != nil {
		return fmt.Errorf("delete smoke log: %w", result.Error)
	}
	if result.RowsAffected == 0 {
		return ErrSmokeLogNotFound
	}
	return nil
}