package dispute

import (
	"context"
	"strconv"
	"strings"

	"gorm.io/gorm"
)

func (r *Repository) ListForUser(ctx context.Context, userID uint64, page, pageSize int) (*PaginatedResult, error) {
	conditions := r.userVisibleQuery(ctx, userID)
	var total int64
	if err := conditions.Count(&total).Error; err != nil {
		return nil, err
	}
	offset := (page - 1) * pageSize
	var rows []disputeRow
	err := applyUserVisibleFilter(r.baseQuery(ctx), userID).
		Order("d.id DESC").
		Offset(offset).Limit(pageSize).
		Scan(&rows).Error
	if err != nil {
		return nil, err
	}
	return &PaginatedResult{Items: toDTOs(rows), Total: total, Page: page, PageSize: pageSize}, nil
}

func (r *Repository) FindForUser(ctx context.Context, userID uint64, id uint64) (*DisputeDTO, error) {
	var row disputeRow
	if err := applyUserVisibleFilter(r.baseQuery(ctx).Where("d.id = ?", id), userID).
		First(&row).Error; err != nil {
		return nil, err
	}
	dto := row.toDTO()
	return &dto, nil
}

func (r *Repository) ListAdmin(ctx context.Context, query AdminListQuery) (*PaginatedResult, error) {
	page := query.Page
	pageSize := query.PageSize
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 20
	}
	offset := (page - 1) * pageSize

	var rows []disputeRow
	err := applyAdminListFilters(r.baseQuery(ctx), query).
		Order("d.id DESC").
		Offset(offset).
		Limit(pageSize).
		Scan(&rows).Error
	if err != nil {
		return nil, err
	}

	var total int64
	// 首页查询且返回条数小于 pageSize 时，总数等于当前返回条数，彻底免除第二次 COUNT(*) 扫描
	if page == 1 && len(rows) < pageSize {
		total = int64(len(rows))
	} else {
		countDB := applyAdminListFilters(r.adminDisputeCountQuery(ctx, query), query)
		if err := countDB.Count(&total).Error; err != nil {
			return nil, err
		}
	}
	return &PaginatedResult{Items: toDTOs(rows), Total: total, Page: page, PageSize: pageSize}, nil
}

func (r *Repository) FindAdminByID(ctx context.Context, id uint64) (*DisputeDTO, error) {
	var row disputeRow
	if err := r.baseQuery(ctx).Where("d.id = ?", id).First(&row).Error; err != nil {
		return nil, err
	}
	dto := row.toDTO()
	return &dto, nil
}

func (r *Repository) userVisibleQuery(ctx context.Context, userID uint64) *gorm.DB {
	return applyUserVisibleFilter(r.adminFilterQuery(ctx), userID)
}

func applyUserVisibleFilter(db *gorm.DB, userID uint64) *gorm.DB {
	return db.Where(
		`((d.initiator_type = ? AND d.initiator_id = ?) OR d.target_user_id = ? OR (d.initiator_type = ? AND (o.owner_id = ? OR o.renter_id = ?)))`,
		disputeInitiatorUser,
		userID,
		userID,
		disputeInitiatorAdmin,
		userID,
		userID,
	)
}

func (r *Repository) baseQuery(ctx context.Context) *gorm.DB {
	return r.adminFilterQuery(ctx).
		Select(`d.*, o.order_no, o.status AS order_status, o.handoff_status, o.settlement_status,
				o.owner_id, o.renter_id, o.extra_item_original_amount_cent,
				owner.phone AS owner_phone, renter.phone AS renter_phone,
				l.listing_no, a.title, c.coin_consumed_m AS checkout_coin_consumed_m,
				c.consumable_amount_cent AS checkout_consumable_amount_cent,
				CASE WHEN c.deposit_deduct_amount_cent > 0 THEN c.deposit_deduct_amount_cent ELSE c.other_amount_cent END AS checkout_deposit_deduct_amount_cent`)
}

func (r *Repository) adminFilterQuery(ctx context.Context) *gorm.DB {
	return r.db.WithContext(ctx).Table("disputes AS d").
		Joins("JOIN rental_orders AS o ON o.id = d.order_id").
		Joins("JOIN rental_listings AS l ON l.id = o.listing_id").
		Joins("JOIN game_accounts AS a ON a.id = o.account_id").
		Joins("JOIN users AS owner ON owner.id = o.owner_id").
		Joins("JOIN users AS renter ON renter.id = o.renter_id").
		Joins("LEFT JOIN order_checkouts AS c ON c.id = d.checkout_id")
}

func (r *Repository) adminDisputeCountQuery(ctx context.Context, query AdminListQuery) *gorm.DB {
	kw := strings.TrimSpace(query.Keyword)
	if kw == "" {
		return r.db.WithContext(ctx).Table("disputes AS d")
	}
	upper := strings.ToUpper(kw)
	if id, err := strconv.ParseUint(kw, 10, 64); err == nil && id > 0 && kw[0] != '0' && id < 100000000 {
		return r.db.WithContext(ctx).Table("disputes AS d").
			Joins("JOIN rental_orders AS o ON o.id = d.order_id")
	}
	if strings.HasPrefix(upper, "RO") || strings.HasPrefix(upper, "ORD") {
		return r.db.WithContext(ctx).Table("disputes AS d").
			Joins("JOIN rental_orders AS o ON o.id = d.order_id")
	}
	if strings.HasPrefix(upper, "L") || (len(kw) >= 12 && isAllDigits(kw)) {
		return r.db.WithContext(ctx).Table("disputes AS d").
			Joins("JOIN rental_orders AS o ON o.id = d.order_id").
			Joins("JOIN rental_listings AS l ON l.id = o.listing_id")
	}
	if len(kw) == 11 && kw[0] == '1' && isAllDigits(kw) {
		return r.db.WithContext(ctx).Table("disputes AS d").
			Joins("JOIN rental_orders AS o ON o.id = d.order_id").
			Joins("JOIN users AS owner ON owner.id = o.owner_id").
			Joins("JOIN users AS renter ON renter.id = o.renter_id")
	}
	return r.adminFilterQuery(ctx)
}

func applyAdminListFilters(db *gorm.DB, query AdminListQuery) *gorm.DB {
	if query.Status != "" {
		db = db.Where("d.status = ?", query.Status)
	}
	if query.Type != "" {
		db = db.Where("d.type = ?", query.Type)
	}
	if keyword := strings.TrimSpace(query.Keyword); keyword != "" {
		upper := strings.ToUpper(keyword)
		if len(keyword) == 11 && keyword[0] == '1' && isAllDigits(keyword) {
			// 11 位手机号：命中 users(phone) 唯一索引
			db = db.Where("(owner.phone = ? OR renter.phone = ?)", keyword, keyword)
		} else if strings.HasPrefix(upper, "RO") || strings.HasPrefix(upper, "ORD") {
			// 订单号：命中 rental_orders(order_no) 唯一索引
			db = db.Where("o.order_no = ?", keyword)
		} else if strings.HasPrefix(upper, "L") || (len(keyword) >= 12 && isAllDigits(keyword)) {
			// 商品编号（如 L前缀或时间计算生成的 12位纯数字如 202609040184）：命中 rental_listings(listing_no) 唯一索引
			db = db.Where("l.listing_no = ?", keyword)
		} else if id, err := strconv.ParseUint(keyword, 10, 64); err == nil && id > 0 && keyword[0] != '0' && id < 100000000 {
			// 短纯数字 ID（非零开头）：命中纠纷 ID、订单 ID 或关联 ID
			db = db.Where("(d.id = ? OR d.order_id = ? OR o.listing_id = ? OR o.owner_id = ? OR o.renter_id = ?)", id, id, id, id, id)
		} else {
			like := "%" + keyword + "%"
			db = db.Where(
				`(o.order_no LIKE ? OR l.listing_no LIKE ? OR a.title LIKE ? OR owner.phone LIKE ? OR renter.phone LIKE ?)`,
				like,
				like,
				like,
				like,
				like,
			)
		}
	}
	return db
}

func isAllDigits(s string) bool {
	if s == "" {
		return false
	}
	for i := 0; i < len(s); i++ {
		if s[i] < '0' || s[i] > '9' {
			return false
		}
	}
	return true
}