using Fake.Application;
using Fake.Rbac.Infrastructure;
using Microsoft.EntityFrameworkCore;

namespace Oms.Application.Shared;

/// <summary>
/// 微信/客户注册前校验 RBAC 登录账号，避免 user 表已存在但 t_customer 未创建时 EF 抛出英文 DbUpdateException。
/// </summary>
public static class OmsRbacRegistrationGuard
{
    public static async Task EnsureLoginIdentityAvailableAsync(
        FakeRbacDbContext rbacDbContext,
        string account,
        string? email,
        CancellationToken cancellationToken = default)
    {
        var normalizedAccount = account.Trim();
        var normalizedEmail = string.IsNullOrWhiteSpace(email) ? null : email.Trim();

        if (await ExistsActiveUserByAccountAsync(rbacDbContext, normalizedAccount, cancellationToken))
        {
            throw new BusinessException("登录账号已存在，请直接绑定或使用其他手机号");
        }

        if (normalizedEmail != null
            && await ExistsActiveUserByEmailAsync(rbacDbContext, normalizedEmail, cancellationToken))
        {
            throw new BusinessException("邮箱已被占用，请更换邮箱或直接绑定已有账号");
        }
    }

    public static BusinessException ToSaveBusinessException(Exception ex)
    {
        var message = ExtractDeepMessage(ex);
        if (ContainsDuplicateKey(message))
        {
            if (message.Contains("Account", StringComparison.OrdinalIgnoreCase)
                || message.Contains("uk_user_account", StringComparison.OrdinalIgnoreCase)
                || message.Contains("IX_user_Account", StringComparison.OrdinalIgnoreCase))
            {
                return new BusinessException("登录账号已存在，请直接绑定或使用其他手机号");
            }

            if (message.Contains("Email", StringComparison.OrdinalIgnoreCase)
                || message.Contains("uk_user_email", StringComparison.OrdinalIgnoreCase))
            {
                return new BusinessException("邮箱已被占用，请更换邮箱或直接绑定已有账号");
            }

            if (message.Contains("Phone", StringComparison.OrdinalIgnoreCase)
                || message.Contains("uk_cus_phone", StringComparison.OrdinalIgnoreCase))
            {
                return new BusinessException("手机号已存在");
            }

            if (message.Contains("uk_cus_email", StringComparison.OrdinalIgnoreCase))
            {
                return new BusinessException("邮箱已存在");
            }

            if (message.Contains("WechatOpenid", StringComparison.OrdinalIgnoreCase)
                || message.Contains("uk_cus_openid", StringComparison.OrdinalIgnoreCase)
                || message.Contains("uk_customer_wechat_openid", StringComparison.OrdinalIgnoreCase))
            {
                return new BusinessException("当前微信已绑定账号");
            }

            return new BusinessException("账号信息已存在，请直接绑定或更换手机号/邮箱");
        }

        if (message.Contains("Data too long", StringComparison.OrdinalIgnoreCase)
            || message.Contains("1406", StringComparison.OrdinalIgnoreCase))
        {
            if (message.Contains("Avatar", StringComparison.OrdinalIgnoreCase))
            {
                return new BusinessException("微信头像地址过长，请稍后重试或联系客服");
            }

            if (message.Contains("Nickname", StringComparison.OrdinalIgnoreCase)
                || message.Contains("CustomerName", StringComparison.OrdinalIgnoreCase)
                || message.Contains("Name", StringComparison.OrdinalIgnoreCase))
            {
                return new BusinessException("客户名称或微信昵称过长，请修改后重试");
            }

            return new BusinessException("注册信息字段过长，请缩短客户名称后重试");
        }

        if (message.Contains("foreign key constraint fails", StringComparison.OrdinalIgnoreCase)
            || message.Contains("1452", StringComparison.OrdinalIgnoreCase))
        {
            return new BusinessException("客户角色未正确初始化，请联系管理员");
        }

        if (message.Contains("Cannot insert duplicate key", StringComparison.OrdinalIgnoreCase)
            || message.Contains("2627", StringComparison.OrdinalIgnoreCase))
        {
            return new BusinessException("账号信息已存在，请直接绑定或更换手机号/邮箱");
        }

        var reason = ExtractActionableReason(ex);
        return new BusinessException($"注册失败：{reason}");
    }

    private static string ExtractActionableReason(Exception ex)
    {
        var parts = new List<string>();
        for (var current = ex; current != null; current = current.InnerException)
        {
            if (string.IsNullOrWhiteSpace(current.Message))
            {
                continue;
            }

            if (current.Message.Contains("saving the entity changes", StringComparison.OrdinalIgnoreCase))
            {
                continue;
            }

            parts.Add(current.Message.Trim());
        }

        var reason = parts.LastOrDefault();
        if (string.IsNullOrWhiteSpace(reason))
        {
            return "请稍后重试或联系客服";
        }

        return reason.Length <= 160 ? reason : reason[..160];
    }

    private static async Task<bool> ExistsActiveUserByAccountAsync(
        FakeRbacDbContext rbacDbContext,
        string account,
        CancellationToken cancellationToken)
    {
        // 唯一索引不按 IsDeleted 区分，软删除账号仍会触发 Duplicate entry。
        var hit = await rbacDbContext.Database
            .SqlQuery<int?>(
                $"SELECT 1 AS Value FROM `user` WHERE `Account` = {account} LIMIT 1")
            .FirstOrDefaultAsync(cancellationToken);
        return hit.HasValue;
    }

    private static async Task<bool> ExistsActiveUserByEmailAsync(
        FakeRbacDbContext rbacDbContext,
        string email,
        CancellationToken cancellationToken)
    {
        var hit = await rbacDbContext.Database
            .SqlQuery<int?>(
                $"SELECT 1 AS Value FROM `user` WHERE `Email` = {email} LIMIT 1")
            .FirstOrDefaultAsync(cancellationToken);
        return hit.HasValue;
    }

    private static string ExtractDeepMessage(Exception ex)
    {
        var parts = new List<string>();
        for (var current = ex; current != null; current = current.InnerException)
        {
            if (!string.IsNullOrWhiteSpace(current.Message))
            {
                parts.Add(current.Message);
            }
        }

        return string.Join(" | ", parts);
    }

    private static bool ContainsDuplicateKey(string message) =>
        message.Contains("Duplicate entry", StringComparison.OrdinalIgnoreCase)
        || message.Contains("1062", StringComparison.OrdinalIgnoreCase)
        || message.Contains("unique constraint", StringComparison.OrdinalIgnoreCase)
        || message.Contains("UNIQUE constraint failed", StringComparison.OrdinalIgnoreCase);
}