using System;
using System.Configuration;
using System.Net;
using System.Text;
using System.Web.Script.Serialization;

public partial class WorkshopSchedule : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e) { }

    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        string username = txtUsername.Text.Trim();
        if (string.IsNullOrEmpty(username))
        {
            // Simple alert for empty input
            ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('Please enter a valid Reg No or Student ID');", true);
            return;
        }

        // 1. Prepare UI state
        InputPanel.Visible = false;
        LoadingPanel.Visible = true;
        ResultPanel.Visible = false; // Hide previous results

        try
        {
            // 2. Prepare API Data
            string clientId = ConfigurationManager.AppSettings["ClientId"];
            string clientKey = ConfigurationManager.AppSettings["ClientKey"];

            var requestData = new { username = username, client_id = clientId, client_key = clientKey };

            JavaScriptSerializer js = new JavaScriptSerializer();
            string jsonRequest = js.Serialize(requestData);

            // 3. Call API
            using (WebClient client = new WebClient())
            {
                client.Headers[HttpRequestHeader.ContentType] = "application/json";
                string responseString = client.UploadString("https://amcr.aiou.edu.pk/api/get_schedule3", jsonRequest);

                var data = js.Deserialize<ApiResponse>(responseString);

                // 4. Check for No Record Found
                if (data == null || data.user_info == null || data.workshop_info == null || data.workshop_info.Length == 0)
                {
                    ShowError("No workshop schedule found for the entered ID/Reg No. Please verify your input.");
                    return;
                }

                // 5. Display Results
                lblStudentName.Text = data.user_info.ST_NAME;
                lblStudentID.Text = data.user_info.ROLLNO;

                gvWorkshop.DataSource = data.workshop_info;
                gvWorkshop.DataBind();

                ResultPanel.Visible = true;
            }
        }
        catch (WebException webEx)
        {
            // Handle specific web request errors (e.g., API server down)
            ShowError("Connection Error: Could not retrieve data from the server. Please try again later.");
        }
        catch (Exception ex)
        {
            // Handle other general errors
            ShowError("An unexpected error occurred: " + ex.Message);
        }
        finally
        {
            // 6. Final UI State
            LoadingPanel.Visible = false;
        }
    }

    private void ShowError(string message)
    {
        // Replace single quotes to prevent JavaScript injection/syntax errors
        string safeMessage = message.Replace("'", "\\'"); 
        
        // Use $"" for cleaner string formatting
        string script = $@"
            document.getElementById('errorText').innerText='{safeMessage}';
            var myModal = new bootstrap.Modal(document.getElementById('errorModal'));
            myModal.show();";
            
        // Use a unique key for the script
        ClientScript.RegisterStartupScript(this.GetType(), "errorModalScript", script, true);

        // Reset display to the input panel
        InputPanel.Visible = true;
        LoadingPanel.Visible = false;
        ResultPanel.Visible = false; 
    }
}

// Classes for API response
public class ApiResponse
{
    public UserInfo user_info { get; set; }
    public WorkshopInfo[] workshop_info { get; set; }
}

public class UserInfo
{
    public string ST_NAME { get; set; }
    public string ROLLNO { get; set; }
}

public class WorkshopInfo
{
    public string Course_code { get; set; }
    public string Group { get; set; }
    public string Start_Date { get; set; }
    public string End_Date { get; set; }
}