using Microsoft.AspNetCore.Mvc;
using System.Collections.Generic;
using Npgsql;
using System.Net;

namespace download;

public class ApiController : Controller
{
    public IActionResult Get(string? key)
    {
        FileObject? file = GetDownload(key);

        if (file == null)
        {
            return StatusCode((int)HttpStatusCode.NotFound, String.Empty);
        }

        RecordDownload(key,
                       Request?.HttpContext?.Connection?.RemoteIpAddress?.ToString() ?? "IP address unknown",
                       Request?.Headers?.UserAgent.ToString() ?? "User agent unknown",
                       DateTime.UtcNow);
        
        return File(file.Data, file.MimeType, file.FileName);
    }

    private FileObject? GetDownload(string key)
    {
        FileObject? ret = null;

        try
        {
            using var conn = new NpgsqlConnection(Config.Settings["ConnectionStrings:download"]);

            conn.Open();

            using var cmd = new NpgsqlCommand("SELECT mime_type, file_name, data FROM file_object WHERE key = @key", conn);
            cmd.Parameters.AddWithValue("key", NpgsqlTypes.NpgsqlDbType.Varchar, key);
            using var reader = cmd.ExecuteReader();

            if(reader.Read())
            {
                ret = new FileObject(key, (string)reader["mime_type"], (string)reader["file_name"], (byte[])reader["data"]);
            }
        }
        catch(Exception e)
        {
            System.Diagnostics.Debug.WriteLine("GetDownload: Caught exception {0} - {1}", e.GetType().ToString(), e.Message);
        }

        return ret;
    }

    private void RecordDownload(string key, string ip_address, string user_agent, DateTime time)
    {
        try
        {
            using var conn = new NpgsqlConnection(Config.Settings["ConnectionStrings:download"]);

            conn.Open();

            using var cmd = new NpgsqlCommand("INSERT INTO file_object (key, ip_address, user_agent, time) VALUES (@key, @ip_address, @user_agent, @time)", conn);

            if (user_agent.Length > 256)
            {
                user_agent = user_agent.Substring(0,256);
            }

            cmd.Parameters.AddWithValue("key", NpgsqlTypes.NpgsqlDbType.Varchar, key);
            cmd.Parameters.AddWithValue("ip_address", NpgsqlTypes.NpgsqlDbType.Varchar, ip_address);
            cmd.Parameters.AddWithValue("user_agent", NpgsqlTypes.NpgsqlDbType.Varchar, user_agent);
            cmd.Parameters.AddWithValue("time", NpgsqlTypes.NpgsqlDbType.Timestamp, time);

            cmd.ExecuteNonQuery();
        }
        catch(Exception e)
        {
            System.Diagnostics.Debug.WriteLine("RecordDownload: Caught exception {0} - {1}", e.GetType().ToString(), e.Message);
        }
    }
}