package repository

import (
	"database/sql"
	"fmt"
	"strings"

	"cmautobuy/admin/model"
)

// UpsertClient 登记或更新一台客户端。
//
// 注意 name 的处理：**只在第一次注册时写入，之后不再更新**。
// 这样操作员在 Admin 界面上改成好记的名字后，客户端每次 claim
// 都不会把它覆盖回去。做法是 ON CONFLICT 的 DO UPDATE 里不含 name。
//
// name 为空时用 clientID 当显示名，保证列表里不出现空白行。
func UpsertClient(db *sql.DB, c model.Client) error {
	if c.ClientID == "" {
		return fmt.Errorf("client_id 不能为空")
	}
	name := c.Name
	if name == "" {
		name = c.ClientID
	}
	now := model.NowISO()

	_, err := db.Exec(`
		INSERT INTO clients (client_id, name, device_address, platform,
		                     pdd_package, capabilities,
		                     last_seen_at, created_at, updated_at)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
		ON CONFLICT(client_id) DO UPDATE SET
		    device_address = excluded.device_address,
		    platform       = excluded.platform,
		    pdd_package    = excluded.pdd_package,
		    capabilities   = excluded.capabilities,
		    last_seen_at   = excluded.last_seen_at,
		    updated_at     = excluded.updated_at`,
		c.ClientID, name, c.DeviceAddress, c.Platform,
		c.PddPackage, c.Capabilities, now, now, now)
	if err != nil {
		return fmt.Errorf("登记客户端 %s 失败: %w", c.ClientID, err)
	}
	return nil
}

// TouchClient 只刷新 last_seen_at。
//
// claim / result / failure 三个接口都要调。只在 claim 里调的话，
// 客户端执行长任务期间不调 claim，会被误判成离线。
func TouchClient(db *sql.DB, clientID string) error {
	now := model.NowISO()
	_, err := db.Exec(
		`UPDATE clients SET last_seen_at = ?, updated_at = ? WHERE client_id = ?`,
		now, now, clientID)
	if err != nil {
		return fmt.Errorf("刷新客户端 %s 活动时间失败: %w", clientID, err)
	}
	return nil
}

// ListClients 按名称模糊查询客户端，keyword 为空时返回全部。
func ListClients(db *sql.DB, keyword string) ([]model.Client, error) {
	query := `SELECT client_id, name, device_address, platform, pdd_package,
	                 capabilities, last_seen_at, created_at, updated_at
	          FROM clients`
	args := []any{}

	if kw := strings.TrimSpace(keyword); kw != "" {
		// 参数化查询，通配符拼在值里而不是 SQL 里
		query += ` WHERE name LIKE ? OR client_id LIKE ?`
		like := "%" + kw + "%"
		args = append(args, like, like)
	}
	query += ` ORDER BY last_seen_at DESC, client_id`

	rows, err := db.Query(query, args...)
	if err != nil {
		return nil, fmt.Errorf("查询客户端列表失败: %w", err)
	}
	defer rows.Close()

	var out []model.Client
	for rows.Next() {
		var c model.Client
		var name, addr, platform, pkg, caps sql.NullString
		if err := rows.Scan(&c.ClientID, &name, &addr, &platform, &pkg,
			&caps, &c.LastSeenAt, &c.CreatedAt, &c.UpdatedAt); err != nil {
			return nil, fmt.Errorf("读取客户端行失败: %w", err)
		}
		c.Name = name.String
		c.DeviceAddress = addr.String
		c.Platform = platform.String
		c.PddPackage = pkg.String
		c.Capabilities = caps.String
		out = append(out, c)
	}
	return out, rows.Err()
}

// DeleteClients 批量删除客户端。返回实际删除的条数。
func DeleteClients(db *sql.DB, clientIDs []string) (int64, error) {
	if len(clientIDs) == 0 {
		return 0, nil
	}

	// 占位符按数量生成，值仍然是参数化传入，不存在注入
	placeholders := strings.TrimSuffix(strings.Repeat("?,", len(clientIDs)), ",")
	args := make([]any, len(clientIDs))
	for i, id := range clientIDs {
		args[i] = id
	}

	res, err := db.Exec(
		`DELETE FROM clients WHERE client_id IN (`+placeholders+`)`, args...)
	if err != nil {
		return 0, fmt.Errorf("删除客户端失败: %w", err)
	}
	return res.RowsAffected()
}