// Copyright © 2017-2025 QL-Win Contributors
//
// This file is part of QuickLook program.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

using CsvHelper;
using CsvHelper.Configuration;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;
using UtfUnknown;

namespace QuickLook.Plugin.CsvViewer;

public partial class CsvViewerPanel : UserControl
{
    public CsvViewerPanel()
    {
        InitializeComponent();
    }

    public List<string[]> Rows { get; private set; } = [];

    public void LoadFile(string path)
    {
        const int limit = 10000;
        var binded = false;

        var encoding = CharsetDetector.DetectFromFile(path).Detected?.Encoding ??
                       Encoding.Default;

        using (var sr = new StreamReader(new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite), encoding))
        {
            var conf = new CsvConfiguration(CultureInfo.CurrentUICulture) { MissingFieldFound = null, BadDataFound = null, DetectDelimiter = true };

            using (var parser = new CsvParser(sr, conf))
            {
                var i = 0;
                while (parser.Read())
                {
                    var row = parser.Record;
                    if (row == null)
                        break;
                    row = Concat([$"{i++ + 1}".PadLeft(6)], row);

                    if (!binded)
                    {
                        SetupColumnBinding(row.Length);
                        binded = true;
                    }

                    if (i > limit)
                    {
                        Rows.Add(Enumerable.Repeat("...", row.Length).ToArray());
                        break;
                    }

                    Rows.Add(row);
                }
            }
        }
    }

    private void SetupColumnBinding(int rowLength)
    {
        for (var i = 0; i < rowLength; i++)
        {
            var col = new DataGridTextColumn
            {
                FontFamily = new FontFamily("Consolas"),
                FontWeight = FontWeight.FromOpenTypeWeight(i == 0 ? 700 : 400),
                Binding = new Binding($"[{i}]")
            };
            dataGrid.Columns.Add(col);
        }
    }

    public static T[] Concat<T>(T[] x, T[] y)
    {
        if (x == null) throw new ArgumentNullException("x");
        if (y == null) throw new ArgumentNullException("y");
        var oldLen = x.Length;
        Array.Resize(ref x, x.Length + y.Length);
        Array.Copy(y, 0, x, oldLen, y.Length);
        return x;
    }
}