CHS Whats App API Setup-Old

Branch Flow call whats app api from service

How the Due Reminders will work

We will have Button for sending reminders or we have scheduler ?
Do we have a System parameter for this or we will have any common System parameter for coming features ?
We will have a different controller or repository called RemindersManagement, or Scheduler need to discuss
Once the DueReminders called we have to get all members list with their dues, additional columns what all we need that will be decided on final template
Once we get the all members list, we have to create json format & store in variable , and send api, this process will be repeated for all members.
json creation from C# is more clear compare to SQL , need to discuss which we want
Once we get the members list or json, now we need to get member cellno, which will check it is valid cellno
Once we get the list json is prepared now, we can send API, once API is return we can check status, if status is failed we can have log
We will have two tables one for success & one for fail like einvoice or only 1 ?
We have to inform to user for what all members message is succeed through report or scheduler or how & in this round only ?

Discussed Doubts

Files name will be different ReminderManagement

Basic Model Structure

System flow

A New Class

public class DueReminder
{
    public string CustomerName { get; set; }
    public string InvoiceId { get; set; }
    public decimal Amount { get; set; }
    public DateTime DueDate { get; set; }
    public string PaymentUrl { get; set; }
}

Repository Query Structure

--Example: List of results from SQL
SELECT 'Amit Sharma' AS CustomerName, 'INV-1001' AS InvoiceId, '12500' AS Amount,'05-Oct-25' AS DueDate, 'https://pay.link' AS PaymentUrl,
'9120080001' AS memberCellNo, '000001' AS memberId

Return Value stored format


//Class store value
var reminders = new List<DueReminder>
{
    new DueReminder
    {
        CustomerName = "Amit Sharma",
        InvoiceId = "INV-1001",
        Amount = 12500,
        DueDate = new DateTime(2025, 10, 5),
        PaymentUrl = "https://pay.link",
        memberCellNo = "9120080001",
        memberId =  "000001"

    },
    //You may have more rows here...
};

appsettings.json API

{
  "WhatsApp": {
    "GraphApiVersion": "v24.0",           // keep configurable
    "PhoneNumberId": "834697629724703", // As per 3rd setup we will get
   // "BusinessAccountId": "YOUR_WABA_ID", // As per 3rd setup we will get
    "TokenKeyVaultSecretName":"EAFgXONjMZBzQBPzF1zmdf25sL9nku12oiNauGoMKJK2o4VAwq62zb2yAJoe1tEvv0VQLJ2eyy26YJgo7zKhsyBhoBbcs7X2WxNblVa2XdRoNHse3nnxZBvI73OyE5VEFLZC0EfRrfWjUxW67bED389qevCYeQtPc9f0DpiW2hBMZC60NiCaPVHJ5apy6MbBMRLMU2Ylma6LBw1NFGEa8B10ePOoLhIz9sIHIkwe3G6u5" // As per 2nd setup
  },
}

Service

public class WhatsAppService : IWhatsAppService
{
    private readonly HttpClient _http;
    private readonly string _phoneNumberId;
    private readonly string _graphVersion;

    public WhatsAppService(IHttpClientFactory httpFactory, IConfiguration cfg)
    {
        _http = httpFactory.CreateClient();

        _phoneNumberId = cfg["WhatsApp:PhoneNumberId"]; 
        _graphVersion = cfg["WhatsApp:GraphApiVersion"];
        var token = cfg["WhatsApp:TokenKeyVaultSecretName"];              

        _http.DefaultRequestHeaders.Authorization =
        new AuthenticationHeaderValue("Bearer", token);
    }

    public async Task<string> SendTemplateAsync(IList<string> reminders)
    {
        var url = $"https://graph.facebook.com/{_graphVersion}/{_phoneNumberId}/messages"; // URL

        // Template Structure
        // Hello {1},  
        // Your invoice {2} of amount {3} is due on {4}.  
        // Pay here: {5}

        var templateComponents = new List<object>();
        //Converting Each Customer Rows in a List  as per above SQL query there will be one row but after converting a columns to list it will become 5 rows for one member
        foreach (var r in reminders)
        {
            var parameters = new List<string>
            {
                r.CustomerName,                   // {1}
                r.InvoiceId,                      // {2}
                $"₹{r.Amount:N0}",                // {3} (12500 → ₹12,500)
                r.DueDate.ToString("dd-MMM-yy"),  // {4} (05-Oct-25)
                r.PaymentUrl                      // {5}
            };
            
            if (parameters?.Any() == true) //creating an array of list values
            {
                var components = new {
                    type = "body",
                    parameters = parameters.Select(p => new { type = "text", text = p }).ToArray()
                };
                templateComponents.Add(components);
            }

            var payload = new {
                messaging_product = "whatsapp",
                to = reminders.memberCellNo, //9120080001
                type = "template",
                template = new {
                    name = "payment_confirmation",
                    language = new { code = "en_US" },
                    components = templateComponents
                }
            };

            var ErrorMsg = "";
            var content = new StringContent(JsonConvert.SerializeObject(payload), Encoding.UTF8, "application/json");
            var resp = await _http.PostAsync(url, content);
            var respBody = await resp.Content.ReadAsStringAsync();
            if (resp.IsSuccessStatusCode)
            {
                // parse id
                var doc = JObject.Parse(respBody);
                var msgId = doc["messages"]?.First?["id"]?.ToString();
                //Write a log
                ErrorMsg = "Success";
            }
            else 
            {
                //Write a Log
                ErrorMsg = "Failed"
            }
            return ErrorMsg

            //After sending if customer replies a mail we should give a static message will get back to you
        }
    }
}

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