using System.Net;
using System.Net.Mail;
using System.Text.Json;
using Fitness_core_BE.Interfaces.Services;
using Fitness_core_BE.Models.IOs;

namespace Fitness_core_BE.Services
{
    /// <summary>
    /// Combines the two outbound notification channels — SMS (Introps) and email (Gmail SMTP) —
    /// into one service, matching the pattern already used by Core-Hex-Auth's ThirdPartyService.
    /// </summary>
    public class ThirdPartyService : IThirdPartyService
    {
        private readonly HttpClient _httpClient;
        private readonly IConfiguration _config;

        // Email (Gmail SMTP). Use a Gmail App Password, not the account password.
        private readonly string _gmailUser;
        private readonly string _gmailPassword;
        private readonly string _gmailHost;
        private readonly int _gmailPort;
        private readonly string _gmailFromName;

        public ThirdPartyService(IHttpClientFactory httpClientFactory, IConfiguration config)
        {
            _httpClient = httpClientFactory.CreateClient();
            _config = config;

            _gmailUser = Environment.GetEnvironmentVariable("GMAIL_USER") ?? config["Gmail:User"] ?? "";
            _gmailPassword = Environment.GetEnvironmentVariable("GMAIL_APP_PASSWORD") ?? config["Gmail:AppPassword"] ?? "";
            _gmailHost = config["Gmail:Host"] ?? "smtp.gmail.com";
            _gmailPort = int.TryParse(config["Gmail:Port"], out var p) ? p : 587;
            _gmailFromName = config["Gmail:FromName"] ?? "GYM OS";
        }

        // ---------- SMS ----------

        public async Task<OtpResponse> SendSmsAsync(string mobileNumber, string? otpCode = null, string? message = null)
        {
            try
            {
                if (string.IsNullOrWhiteSpace(mobileNumber))
                {
                    return new OtpResponse
                    {
                        StatusCode = 400,
                        Message = "Mobile number is required"
                    };
                }

                if (string.IsNullOrWhiteSpace(otpCode) && string.IsNullOrWhiteSpace(message))
                {
                    return new OtpResponse
                    {
                        StatusCode = 400,
                        Message = "Either an OTP code or a message is required"
                    };
                }

                string contactNumber = mobileNumber;
                string apiUrl = _config["Sms:ApiUrl"] ?? "https://backup.introps.com/Sms_common/send_sms";
                string apiKey = Environment.GetEnvironmentVariable("SMS_API_KEY") ?? _config["Sms:ApiKey"] ?? "8989898989";

                var msgText = string.IsNullOrWhiteSpace(message) ? $"Your otp code is: {otpCode}" : message;

                var smsRequest = new SmsRequest
                {
                    api_key = apiKey,
                    phone_number = contactNumber,
                    msg_text = msgText
                };

                var formContent = new FormUrlEncodedContent(new[]
                {
                    new KeyValuePair<string, string>("api_key", smsRequest.api_key),
                    new KeyValuePair<string, string>("phone_number", smsRequest.phone_number),
                    new KeyValuePair<string, string>("msg_text", smsRequest.msg_text)
                });

                var response = await _httpClient.PostAsync(apiUrl, formContent);
                var responseContent = await response.Content.ReadAsStringAsync();

                if (response.IsSuccessStatusCode && responseContent.Contains("agent:d"))
                {
                    string jsonString = responseContent.Split(new[] { "agent:d" }, StringSplitOptions.None)[1];

                    var responseJson = JsonSerializer.Deserialize<Dictionary<string, object>>(jsonString);

                    if (responseJson is not null &&
                        responseJson.TryGetValue("stt", out var statusValue) &&
                        statusValue?.ToString() == "ok")
                    {
                        Console.WriteLine($"SMS sent to {contactNumber}");
                        return new OtpResponse
                        {
                            StatusCode = 200,
                            Message = "SMS sent successfully."
                        };
                    }
                }

                Console.WriteLine($"Failed to send SMS to {contactNumber}. Response: {responseContent}");
                return new OtpResponse
                {
                    StatusCode = 500,
                    Message = "Failed to send SMS.",
                    ApiResponse = responseContent
                };
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Exception sending SMS: {ex.Message}");

                return new OtpResponse
                {
                    StatusCode = 500,
                    Message = "Exception occurred while sending SMS.",
                    Error = ex.Message
                };
            }
        }

        // ---------- Email ----------

        public async Task SendEmailAsync(string toEmail, string subject, string htmlBody, byte[]? attachment = null, string? attachmentName = null)
        {
            if (string.IsNullOrWhiteSpace(_gmailUser) || string.IsNullOrWhiteSpace(_gmailPassword))
                throw new InvalidOperationException("Gmail SMTP is not configured (set GMAIL_USER / GMAIL_APP_PASSWORD).");

            using var mail = new MailMessage
            {
                From = new MailAddress(_gmailUser, _gmailFromName),
                Subject = subject,
                Body = htmlBody,
                IsBodyHtml = true
            };
            mail.To.Add(toEmail);

            MemoryStream? attachmentStream = null;
            if (attachment != null)
            {
                attachmentStream = new MemoryStream(attachment);
                mail.Attachments.Add(new Attachment(attachmentStream, attachmentName ?? "receipt.pdf", "application/pdf"));
            }

            try
            {
                using var client = new SmtpClient(_gmailHost, _gmailPort)
                {
                    EnableSsl = true,
                    Credentials = new NetworkCredential(_gmailUser, _gmailPassword)
                };
                await client.SendMailAsync(mail);
            }
            finally
            {
                attachmentStream?.Dispose();
            }
        }
    }
}