package repository

import (
	"context"
	"errors"
	"strconv"
	"time"

	"fashionapi/internal/dto"
	"fashionapi/internal/model"

	"gorm.io/gorm"
)

// StreetSnapRepository 街拍数据访问接口。
type StreetSnapRepository interface {
	// List 按筛选条件分页查询街拍，同时返回符合条件的总数。
	List(ctx context.Context, q dto.StreetSnapQuery) ([]model.StreetSnap, int64, error)
	// FindByID 查询单条街拍；不存在时返回 ErrNotFound。
	FindByID(ctx context.Context, id string) (*model.StreetSnap, error)
	// ListImages 查询某条街拍的全部图片，按排序值升序。
	ListImages(ctx context.Context, snapID string) ([]model.StreetSnapImage, error)
	// ImagesBySnapIDs 批量查询多条街拍的图片，单次 IN 查询避免 N+1。
	ImagesBySnapIDs(ctx context.Context, ids []uint32) (map[uint32][]model.StreetSnapImage, error)
	// Popular 按图片数降序返回热度前 N 个街拍，供 SSG 首页热门街拍使用。
	Popular(ctx context.Context, limit int) ([]model.StreetSnap, error)
	// GetForEdit 取原始街拍记录与图片，供后台编辑表单预填。
	GetForEdit(ctx context.Context, id uint32) (*model.StreetSnap, []model.StreetSnapImage, error)
	// UpdateSnap 编辑后更新字段（白名单，杜绝任意列注入）。
	UpdateSnap(ctx context.Context, id uint32, fields map[string]any) error
	// DeleteSnapImage 软删单张街拍图片。
	DeleteSnapImage(ctx context.Context, imageID uint32) error
	// GetSnapImageKey 取单张街拍图片的S4 key（删除前清理用）；不存在返回空串。
	GetSnapImageKey(ctx context.Context, imageID uint32) (string, error)
	// SoftDeleteSnapImages 软删某街拍的全部图片（级联下架用），返回被删图片的 key 列表。
	SoftDeleteSnapImages(ctx context.Context, snapID uint32) ([]string, error)
	// SetSnapCover 更新街拍封面。
	SetSnapCover(ctx context.Context, snapID uint32, image string) error
	// SetSnapDeleted 上下架：deleted=1 下架，0 上架。
	SetSnapDeleted(ctx context.Context, id uint32, deleted uint8) error
}

type streetSnapRepository struct {
	db *gorm.DB
}

// NewStreetSnapRepository 创建街拍仓储。
func NewStreetSnapRepository(db *gorm.DB) StreetSnapRepository {
	return &streetSnapRepository{db: db}
}

// filterScope 把查询条件编译为 GORM Scope（白名单化，杜绝 SQL 注入）。
func snapFilterScope(q dto.StreetSnapQuery) func(*gorm.DB) *gorm.DB {
	return func(db *gorm.DB) *gorm.DB {
		db = db.Where("is_deleted = 0")
		if q.Year != 0 {
			db = db.Where("year = ?", q.Year)
		}
		if q.City != "" {
			db = db.Where("city = ?", q.City)
		}
		return db
	}
}

// snapOrderBy 把 sort 参数映射为 ORDER BY（白名单，杜绝注入）。
func snapOrderBy(sort string) string {
	switch sort {
	case "year_asc":
		return "street_snaps.year ASC, street_snaps.id ASC"
	case "year_desc":
		return "street_snaps.year DESC, street_snaps.id DESC"
	default: // image_count
		return "street_snaps.image_count DESC, street_snaps.id DESC"
	}
}

func (r *streetSnapRepository) List(ctx context.Context, q dto.StreetSnapQuery) ([]model.StreetSnap, int64, error) {
	scope := snapFilterScope(q)

	var total int64
	if err := r.db.WithContext(ctx).
		Model(&model.StreetSnap{}).
		Scopes(scope).
		Count(&total).Error; err != nil {
		return nil, 0, err
	}
	if total == 0 {
		return []model.StreetSnap{}, 0, nil
	}

	var rows []model.StreetSnap
	if err := r.db.WithContext(ctx).
		Model(&model.StreetSnap{}).
		Scopes(scope).
		Order(snapOrderBy(q.Sort)).
		Offset(q.Offset()).
		Limit(q.Size).
		Find(&rows).Error; err != nil {
		return nil, 0, err
	}
	return rows, total, nil
}

func (r *streetSnapRepository) FindByID(ctx context.Context, id string) (*model.StreetSnap, error) {
	var snap model.StreetSnap
	err := r.db.WithContext(ctx).
		Where("id = ? AND is_deleted = 0", id).
		First(&snap).Error
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrNotFound
		}
		return nil, err
	}
	return &snap, nil
}

func (r *streetSnapRepository) ListImages(ctx context.Context, snapID string) ([]model.StreetSnapImage, error) {
	var imgs []model.StreetSnapImage
	err := r.db.WithContext(ctx).
		Where("snap_id = ? AND is_deleted = 0", snapID).
		Order("sort_order ASC, id ASC").
		Find(&imgs).Error
	return imgs, err
}

func (r *streetSnapRepository) ImagesBySnapIDs(ctx context.Context, ids []uint32) (map[uint32][]model.StreetSnapImage, error) {
	result := make(map[uint32][]model.StreetSnapImage, len(ids))
	if len(ids) == 0 {
		return result, nil
	}

	var imgs []model.StreetSnapImage
	err := r.db.WithContext(ctx).
		Select("snap_id, image, name, sort_order").
		Where("snap_id IN ? AND is_deleted = 0", ids).
		Order("sort_order ASC, id ASC").
		Find(&imgs).Error
	if err != nil {
		return nil, err
	}
	for _, im := range imgs {
		result[im.SnapID] = append(result[im.SnapID], im)
	}
	return result, nil
}

// IDs 返回全部未删除街拍的 id（升序），供 SSG 构建期枚举详情页路径。
// Popular 按图片数降序返回热度前 N 个街拍（SSG 首页热门街拍用）。
func (r *streetSnapRepository) Popular(ctx context.Context, limit int) ([]model.StreetSnap, error) {
	var rows []model.StreetSnap
	if err := r.db.WithContext(ctx).
		Where("is_deleted = 0").
		Order("image_count DESC, id DESC").
		Limit(limit).
		Find(&rows).Error; err != nil {
		return nil, err
	}
	return rows, nil
}

// ── 后台编辑支持 ──────────────────────────────────────────────────────────────

// snapEditable 后台可编辑的街拍字段白名单（键即列名）。
var snapEditable = map[string]bool{
	"title": true,
	"year":  true,
	"city":  true,
	"cover": true,
}

func (r *streetSnapRepository) GetForEdit(ctx context.Context, id uint32) (*model.StreetSnap, []model.StreetSnapImage, error) {
	var snap model.StreetSnap
	if err := r.db.WithContext(ctx).Where("id = ? AND is_deleted = 0", id).First(&snap).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, nil, ErrNotFound
		}
		return nil, nil, err
	}
	imgs, err := r.ListImages(ctx, strconv.FormatUint(uint64(id), 10))
	if err != nil {
		return nil, nil, err
	}
	return &snap, imgs, nil
}

func (r *streetSnapRepository) UpdateSnap(ctx context.Context, id uint32, fields map[string]any) error {
	clean := map[string]any{}
	for k, v := range fields {
		if snapEditable[k] {
			clean[k] = v
		}
	}
	if len(clean) == 0 {
		return nil
	}
	clean["updated_at"] = uint32(time.Now().Unix())
	return r.db.WithContext(ctx).
		Model(&model.StreetSnap{}).
		Where("id = ?", id).
		Updates(clean).Error
}

func (r *streetSnapRepository) DeleteSnapImage(ctx context.Context, imageID uint32) error {
	return r.db.WithContext(ctx).
		Model(&model.StreetSnapImage{}).
		Where("id = ? AND is_deleted = 0", imageID).
		Updates(map[string]any{"is_deleted": 1, "updated_at": uint32(time.Now().Unix())}).Error
}

func (r *streetSnapRepository) GetSnapImageKey(ctx context.Context, imageID uint32) (string, error) {
	var img model.StreetSnapImage
	err := r.db.WithContext(ctx).Where("id = ?", imageID).First(&img).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return "", nil
	}
	if err != nil {
		return "", err
	}
	return img.Image, nil
}

// SoftDeleteSnapImages 软删某街拍的全部图片（级联下架用）。
// 先取非删除图片的 key 列表返回给调用方（用于后续S4孤儿清理），再统一置 is_deleted=1。
func (r *streetSnapRepository) SoftDeleteSnapImages(ctx context.Context, snapID uint32) ([]string, error) {
	var imgs []model.StreetSnapImage
	if err := r.db.WithContext(ctx).
		Select("image").
		Where("snap_id = ? AND is_deleted = 0", snapID).
		Find(&imgs).Error; err != nil {
		return nil, err
	}
	keys := make([]string, 0, len(imgs))
	for _, im := range imgs {
		if im.Image != "" {
			keys = append(keys, im.Image)
		}
	}
	if err := r.db.WithContext(ctx).
		Model(&model.StreetSnapImage{}).
		Where("snap_id = ? AND is_deleted = 0", snapID).
		Updates(map[string]any{"is_deleted": 1, "updated_at": uint32(time.Now().Unix())}).Error; err != nil {
		return nil, err
	}
	return keys, nil
}

func (r *streetSnapRepository) SetSnapCover(ctx context.Context, snapID uint32, image string) error {
	return r.db.WithContext(ctx).
		Model(&model.StreetSnap{}).
		Where("id = ?", snapID).
		Updates(map[string]any{"cover": image, "updated_at": uint32(time.Now().Unix())}).Error
}

func (r *streetSnapRepository) SetSnapDeleted(ctx context.Context, id uint32, deleted uint8) error {
	return r.db.WithContext(ctx).
		Model(&model.StreetSnap{}).
		Where("id = ?", id).
		Updates(map[string]any{"is_deleted": deleted, "updated_at": uint32(time.Now().Unix())}).Error
}