package service

import (
	"fmt"
	"time"

	"gorm.io/datatypes"
	"gorm.io/gorm"

	"github.com/sundynix/pets-be/internal/model"
)

// RecordInput 健康记录入参
type RecordInput struct {
	Type        string
	Icon        string
	Title       string
	Description string
	NumValue    float64
	Category    string
	ImageURL    string
	ImageFileID string
	Extra       datatypes.JSON
	OccurredAt  *time.Time
}

// ListRecords 列出宠物的健康记录（可按 type 过滤）
func (s *Service) ListRecords(userID, petID string, recordType string, offset, limit int) ([]model.HealthRecord, int64, error) {
	if _, err := s.ownedPet(userID, petID); err != nil {
		return nil, 0, err
	}
	q := s.db.Model(&model.HealthRecord{}).Where("pet_id = ?", petID)
	if recordType != "" {
		q = q.Where("type = ?", recordType)
	}
	var total int64
	if err := q.Count(&total).Error; err != nil {
		return nil, 0, err
	}
	var records []model.HealthRecord
	err := q.Order("occurred_at desc, id desc").Offset(offset).Limit(limit).Find(&records).Error
	// 用 file_id 回填图片 URL
	ids := make([]string, 0)
	for i := range records {
		if records[i].ImageFileID != "" && records[i].ImageURL == "" {
			ids = append(ids, records[i].ImageFileID)
		}
	}
	if len(ids) > 0 {
		urls := s.fileURLs(ids)
		for i := range records {
			if records[i].ImageURL == "" {
				records[i].ImageURL = urls[records[i].ImageFileID]
			}
		}
	}
	return records, total, err
}

// CreateRecord 新增健康记录；weight 类型同步更新宠物体重
func (s *Service) CreateRecord(userID, petID string, in RecordInput) (*model.HealthRecord, error) {
	pet, err := s.ownedPet(userID, petID)
	if err != nil {
		return nil, err
	}
	occurred := time.Now()
	if in.OccurredAt != nil {
		occurred = *in.OccurredAt
	}
	rec := model.HealthRecord{
		PetID: petID, UserID: userID, Type: in.Type, Icon: in.Icon,
		Title: in.Title, Description: in.Description, NumValue: in.NumValue,
		Category: in.Category, ImageURL: in.ImageURL, ImageFileID: in.ImageFileID, Extra: in.Extra, OccurredAt: occurred,
	}
	// 传了 file_id 未传 url 时，用 file 表的 url 回填 ImageURL 便于直接展示
	if in.ImageFileID != "" && rec.ImageURL == "" {
		rec.ImageURL = s.fileURL(in.ImageFileID)
	}
	if err := s.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Create(&rec).Error; err != nil {
			return err
		}
		if in.Type == model.RecordWeight && in.NumValue > 0 {
			weight := fmt.Sprintf("%gkg", in.NumValue)
			if err := tx.Model(&model.Pet{}).Where("id = ?", pet.ID).Update("weight", weight).Error; err != nil {
				return err
			}
		}
		return nil
	}); err != nil {
		return nil, err
	}
	return &rec, nil
}

// DeleteRecord 删除记录
func (s *Service) DeleteRecord(userID, recordID string) error {
	res := s.db.Where("id = ? AND user_id = ?", recordID, userID).Delete(&model.HealthRecord{})
	if res.Error != nil {
		return res.Error
	}
	if res.RowsAffected == 0 {
		return ErrNotFound
	}
	return nil
}

// WeightPoint 体重趋势点
type WeightPoint struct {
	Value      float64   `json:"value"`
	OccurredAt time.Time `json:"occurred_at"`
	Note       string    `json:"note"` // 记录时填的备注
}

// WeightTrend 最近 N 次体重（升序）
func (s *Service) WeightTrend(userID, petID string, limit int) ([]WeightPoint, error) {
	if _, err := s.ownedPet(userID, petID); err != nil {
		return nil, err
	}
	if limit <= 0 {
		limit = 7
	}
	var records []model.HealthRecord
	if err := s.db.Where("pet_id = ? AND type = ?", petID, model.RecordWeight).
		Order("occurred_at desc").Limit(limit).Find(&records).Error; err != nil {
		return nil, err
	}
	points := make([]WeightPoint, 0, len(records))
	for i := len(records) - 1; i >= 0; i-- {
		points = append(points, WeightPoint{Value: records[i].NumValue, OccurredAt: records[i].OccurredAt, Note: records[i].Description})
	}
	return points, nil
}