using Admin.NET.Core.Service;

namespace Admin.NET.Plugin.ApprovalFlow.Service;

/// <summary>
/// 邮件推送（P4-16）
/// 复用 Admin.NET.Core 的 SysEmailService.SendEmail(content, title, toEmail)，按目标用户 Email 逐个发送。
/// </summary>
public class EmailNotifyPusher : INotifyPusher, ITransient
{
    public string Channel => "Email";

    private readonly SysEmailService _emailService;
    private readonly SqlSugarRepository<SysUser> _userRep;

    public EmailNotifyPusher(SysEmailService emailService, SqlSugarRepository<SysUser> userRep)
    {
        _emailService = emailService;
        _userRep = userRep;
    }

    public bool IsEnabled(NotifyChannelConfig cfg) => cfg?.Email == true;

    public async Task<FlowNotifyPushResult> PushAsync(List<long> userIds, FlowNotification notification)
    {
        if (userIds.Count == 0) return FlowNotifyPushResult.Ok(0);

        var users = await _userRep.AsQueryable()
            .Where(u => userIds.Contains(u.Id) && !string.IsNullOrEmpty(u.Email))
            .Select(u => new { u.Id, u.Email, u.RealName })
            .ToListAsync();

        if (users.Count == 0) return FlowNotifyPushResult.Ok(0);

        var html = $"<p>{System.Net.WebUtility.HtmlEncode(notification.Content)}</p>" +
                   $"<hr><p style='color:#888;font-size:12px'>该邮件由系统自动发送，请勿直接回复。实例 Id：{notification.InstanceId}</p>";

        var errors = new List<string>();
        var successCount = 0;
        foreach (var user in users)
        {
            try
            {
                await _emailService.SendEmail(html, notification.Title, user.Email);
                successCount++;
            }
            catch (Exception ex)
            {
                errors.Add($"[{user.Id}]{ex.Message}");
            }
        }

        if (successCount > 0 && errors.Count == 0)
            return FlowNotifyPushResult.Ok(successCount);
        if (successCount > 0)
            return new FlowNotifyPushResult
            {
                Success = true,
                ActualTargetCount = successCount,
                ErrorMessage = $"部分失败: {string.Join("; ", errors)}"
            };
        return FlowNotifyPushResult.Fail(string.Join("; ", errors));
    }
}