using InstaVibe.Models;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using InstaVibe.Services;

public class NotesController : Controller
{
    private readonly string connectionString = ConfigurationManager.ConnectionStrings["InstaVibe"].ConnectionString;

    // Show all uploaded notes + subjects & semesters dropdown
    public ActionResult AllNotes()
    {
        var notes = GetAllNotes();

        ViewBag.Subjects = new List<string>
        {
            "Mathematics", "Physics", "Chemistry", "Biology", "Botany", "Zoology",
            "English", "Urdu", "Economics", "Psychology", "Sociology", "History",
            "Computer Science", "Political Science", "Education", "Statistics"
        };

        ViewBag.Semesters = new List<string>
        {
            "1st Semester", "2nd Semester", "3rd Semester", "4th Semester",
            "5th Semester", "6th Semester", "7th Semester", "8th Semester"
        };

        return View(notes);
    }

    
    public ActionResult SmartNotes()
    {
        return View(GetAllNotes());
    }

    // ======== Upload new note==============
    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult UploadNote(HttpPostedFileBase file, string title, string courseCode, string subject, string semester)
    {
        if (Session["UserId"] == null)
        {
            TempData["Error"] = "You must be logged in to upload notes.";
            return RedirectToAction("Login", "Account");
        }
        int uploadedBy = Convert.ToInt32(Session["UserId"]);

        if (file == null || file.ContentLength == 0)
        {
            TempData["Error"] = "Please select a file.";
            return RedirectToAction("AllNotes");
        }

        var allowedExt = new[] { ".pdf", ".doc", ".docx", ".ppt", ".pptx", ".xls", ".xlsx", ".txt" };
        var ext = Path.GetExtension(file.FileName)?.ToLowerInvariant();
        if (!allowedExt.Contains(ext))
        {
            TempData["Error"] = "File type not allowed.";
            return RedirectToAction("AllNotes");
        }

        if (file.ContentLength > 50 * 1024 * 1024)
        {
            TempData["Error"] = "File too large (max 50 MB).";
            return RedirectToAction("AllNotes");
        }

        string tempPath = Path.GetTempFileName();
        try
        {
            file.SaveAs(tempPath);

            var scan = WindowsDefender.ScanFile(tempPath);
            if (scan.Result != AvScanResult.Clean)
            {
                System.IO.File.Delete(tempPath);
                TempData["Error"] = (scan.Result == AvScanResult.Infected)
                    ? "Upload blocked: the file appears to contain a virus."
                    : "Could not scan the file. Please try again.";
                return RedirectToAction("AllNotes");
            }

            var uploadsDir = Server.MapPath("~/UploadedNotes");
            Directory.CreateDirectory(uploadsDir);

            string safeFileName = $"{Guid.NewGuid():N}{ext}";
            string finalPath = Path.Combine(uploadsDir, safeFileName);
            System.IO.File.Move(tempPath, finalPath);

            string virtualPath = Url.Content("~/UploadedNotes/" + safeFileName);

            using (var conn = new SqlConnection(connectionString))
            using (var cmd = new SqlCommand(@"
                INSERT INTO Notes (Title, CourseCode, Subject, Semester, FilePath, UploadedBy, UploadedAt)
                VALUES (@Title, @CourseCode, @Subject, @Semester, @FilePath, @UploadedBy, GETDATE());
            ", conn))
            {
                cmd.Parameters.AddWithValue("@Title", title);
                cmd.Parameters.AddWithValue("@CourseCode", courseCode);
                cmd.Parameters.AddWithValue("@Subject", subject);
                cmd.Parameters.AddWithValue("@Semester", semester);
                cmd.Parameters.AddWithValue("@FilePath", virtualPath);
                cmd.Parameters.AddWithValue("@UploadedBy", uploadedBy);

                conn.Open();
                cmd.ExecuteNonQuery();
            }

            TempData["Success"] = "File uploaded successfully!";
            return RedirectToAction("AllNotes");
        }
        catch (Exception ex)
        {
            if (System.IO.File.Exists(tempPath))
                System.IO.File.Delete(tempPath);
            TempData["Error"] = "Upload failed: " + ex.Message;
            return RedirectToAction("AllNotes");
        }
    }

    // ========== Search notes ============
    public JsonResult SearchNotes(string keyword, string subject, string semester)
    {
        var notes = new List<NotesModel>();
        using (var conn = new SqlConnection(connectionString))
        {
            conn.Open();
            string query = "SELECT * FROM Notes WHERE 1=1";

            if (!string.IsNullOrEmpty(keyword))
                query += " AND (Title LIKE @Keyword OR Subject LIKE @Keyword OR Semester LIKE @Keyword OR CourseCode LIKE @Keyword)";
            if (!string.IsNullOrEmpty(subject) && subject != "All")
                query += " AND Subject = @Subject";
            if (!string.IsNullOrEmpty(semester) && semester != "All")
                query += " AND Semester = @Semester";

            using (var cmd = new SqlCommand(query, conn))
            {
                if (!string.IsNullOrEmpty(keyword))
                    cmd.Parameters.AddWithValue("@Keyword", "%" + keyword + "%");
                if (!string.IsNullOrEmpty(subject) && subject != "All")
                    cmd.Parameters.AddWithValue("@Subject", subject);
                if (!string.IsNullOrEmpty(semester) && semester != "All")
                    cmd.Parameters.AddWithValue("@Semester", semester);

                using (var reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        notes.Add(new NotesModel
                        {
                            Id = Convert.ToInt32(reader["Id"]),
                            Title = reader["Title"].ToString(),
                            FilePath = reader["FilePath"].ToString(),
                            Subject = reader["Subject"].ToString(),
                            Semester = reader["Semester"].ToString(),
                            CourseCode = reader["CourseCode"].ToString(),
                            UploadedBy = Convert.ToInt32(reader["UploadedBy"]),
                            UploadedAt = Convert.ToDateTime(reader["UploadedAt"])
                        });
                    }
                }
            }
        }
        return Json(notes, JsonRequestBehavior.AllowGet);
    }

    // ========== Helper to get all notes ============
    private List<NotesModel> GetAllNotes()
    {
        var notes = new List<NotesModel>();
        using (var conn = new SqlConnection(connectionString))
        {
            conn.Open();
            string query = "SELECT * FROM Notes ORDER BY UploadedAt DESC";
            using (var cmd = new SqlCommand(query, conn))
            using (var reader = cmd.ExecuteReader())
            {
                while (reader.Read())
                {
                    notes.Add(new NotesModel
                    {
                        Id = Convert.ToInt32(reader["Id"]),
                        Title = reader["Title"].ToString(),
                        FilePath = reader["FilePath"].ToString(),
                        Subject = reader["Subject"].ToString(),
                        Semester = reader["Semester"].ToString(),
                        CourseCode = reader["CourseCode"].ToString(),
                        UploadedBy = Convert.ToInt32(reader["UploadedBy"]),
                        UploadedAt = Convert.ToDateTime(reader["UploadedAt"])
                    });
                }
            }
        }
        return notes;
    }

    public ActionResult Logout()
    {
        if (Session["UserId"] != null)
        {
            int userId = Convert.ToInt32(Session["UserId"]);
            using (var con = new SqlConnection(connectionString))
            {
                con.Open();
                string query = "UPDATE Users SET is_online = 0 WHERE user_id = @userId";
                using (var cmd = new SqlCommand(query, con))
                {
                    cmd.Parameters.AddWithValue("@userId", userId);
                    cmd.ExecuteNonQuery();
                }
            }
        }
        Session.Clear();
        Session.Abandon();
        return RedirectToAction("Login", "Account");
    }
}