package dao

import (
	"context"
	"fmt"
	"math/rand"
	"time"

	"git.x2erp.com/qdy/go-svc-configure/internal/tables"
	"github.com/jmoiron/sqlx"
)

const (
	invitationCodeLength = 16
	invitationCodeChars  = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	defaultExpiresDays   = 7
)

// GenerateInvitationCode 生成唯一邀请码
func GenerateInvitationCode() string {
	rand.Seed(time.Now().UnixNano())
	b := make([]byte, invitationCodeLength)
	for i := range b {
		b[i] = invitationCodeChars[rand.Intn(len(invitationCodeChars))]
	}
	return string(b)
}

// CreateInvitationCode 创建邀请码
func CreateInvitationCode(ctx context.Context, tx *sqlx.Tx, tenantID, roleID, creator string, expiresDays int) (string, error) {
	if expiresDays <= 0 {
		expiresDays = defaultExpiresDays
	}

	// 生成唯一邀请码
	var code string
	var exists bool
	maxAttempts := 10

	for i := 0; i < maxAttempts; i++ {
		code = GenerateInvitationCode()

		// 检查是否已存在
		var count int
		checkQuery := `SELECT COUNT(*) FROM config_invitation_code WHERE code = ?`
		err := tx.GetContext(ctx, &count, checkQuery, code)
		if err != nil {
			return "", fmt.Errorf("检查邀请码存在性失败: %v", err)
		}

		if count == 0 {
			exists = false
			break
		}
		exists = true
	}

	if exists {
		return "", fmt.Errorf("生成唯一邀请码失败，请重试")
	}

	// 计算过期时间
	expiresAt := time.Now().Add(time.Duration(expiresDays) * 24 * time.Hour)
	id := fmt.Sprintf("invitation.%s.%s.%d", tenantID, roleID, time.Now().Unix())

	query := `
		INSERT INTO config_invitation_code 
		(id, code, tenant_id, role_id, expires_at, used, used_by, creator, created_at)
		VALUES (?, ?, ?, ?, ?, 0, '', ?, CURRENT_TIMESTAMP)
	`

	result, err := tx.ExecContext(ctx, query, id, code, tenantID, roleID, expiresAt, creator)
	if err != nil {
		return "", fmt.Errorf("创建邀请码失败: %v", err)
	}

	rowsAffected, err := ValidateResultRowsAffected(result, err, 1)
	if err != nil {
		return "", err
	}

	if rowsAffected != 1 {
		return "", fmt.Errorf("创建邀请码失败，影响行数: %d", rowsAffected)
	}

	return code, nil
}

// ValidateInvitationCode 验证邀请码有效性
func ValidateInvitationCode(ctx context.Context, db *sqlx.DB, code string) (*tables.InvitationCodeDB, error) {
	var invitation tables.InvitationCodeDB

	query := `
		SELECT id, code, tenant_id, role_id, expires_at, used, used_by, creator, created_at
		FROM config_invitation_code 
		WHERE code = ?
	`

	err := db.GetContext(ctx, &invitation, query, code)
	if err != nil {
		return nil, fmt.Errorf("邀请码不存在: %v", err)
	}

	// 检查是否已使用
	if invitation.Used != 0 {
		return nil, fmt.Errorf("邀请码已使用")
	}

	// 检查是否过期
	if time.Now().After(invitation.ExpiresAt) {
		return nil, fmt.Errorf("邀请码已过期")
	}

	return &invitation, nil
}

// MarkInvitationCodeUsed 标记邀请码已使用
func MarkInvitationCodeUsed(ctx context.Context, tx *sqlx.Tx, code, usedBy string) (int64, error) {
	query := `
		UPDATE config_invitation_code 
		SET used = 1, used_by = ?
		WHERE code = ? AND used = 0
	`

	result, err := tx.ExecContext(ctx, query, usedBy, code)
	if err != nil {
		return -1, fmt.Errorf("标记邀请码已使用失败: %v", err)
	}

	return ValidateResultRowsAffected(result, err, 1)
}

// GetInvitationCodeByCode 根据邀请码查询详情
func GetInvitationCodeByCode(ctx context.Context, db *sqlx.DB, code string) (*tables.InvitationCodeDB, error) {
	var invitation tables.InvitationCodeDB

	query := `
		SELECT id, code, tenant_id, role_id, expires_at, used, used_by, creator, created_at
		FROM config_invitation_code 
		WHERE code = ?
	`

	err := db.GetContext(ctx, &invitation, query, code)
	if err != nil {
		return nil, fmt.Errorf("查询邀请码失败: %v", err)
	}

	return &invitation, nil
}

// ListInvitationCodesByTenant 按租户查询邀请码列表
func ListInvitationCodesByTenant(ctx context.Context, db *sqlx.DB, tenantID string, includeUsed bool) ([]tables.InvitationCodeDB, error) {
	var invitations []tables.InvitationCodeDB

	query := `
		SELECT id, code, tenant_id, role_id, expires_at, used, used_by, creator, created_at
		FROM config_invitation_code 
		WHERE tenant_id = ?
	`

	if !includeUsed {
		query += " AND used = 0"
	}

	query += " ORDER BY created_at DESC"

	err := db.SelectContext(ctx, &invitations, query, tenantID)
	if err != nil {
		return nil, fmt.Errorf("查询邀请码列表失败: %v", err)
	}

	return invitations, nil
}

// DeleteInvitationCode 删除邀请码（仅限未使用的）
func DeleteInvitationCode(ctx context.Context, tx *sqlx.Tx, code string) (int64, error) {
	query := `DELETE FROM config_invitation_code WHERE code = ? AND used = 0`

	result, err := tx.ExecContext(ctx, query, code)
	if err != nil {
		return -1, fmt.Errorf("删除邀请码失败: %v", err)
	}

	return ValidateResultRowsAffected(result, err, 1)
}

// CountInvitationCodesByTenant 统计租户邀请码数量
func CountInvitationCodesByTenant(ctx context.Context, db *sqlx.DB, tenantID string) (int, error) {
	var count int
	query := `SELECT COUNT(*) FROM config_invitation_code WHERE tenant_id = ?`

	err := db.GetContext(ctx, &count, query, tenantID)
	if err != nil {
		return 0, fmt.Errorf("统计邀请码数量失败: %v", err)
	}

	return count, nil
}