using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace PictureMover
{
    public partial class CoverForm : Form
    {
        private readonly MainForm _mainForm;

        private string? _currentPath;

        public CoverForm(MainForm mainForm)
        {
            _mainForm = mainForm;
            InitializeComponent();
            MouseWheel += Form_MouseWheel;
            PreviewKeyDown += Form_PreviewKeyDown;
            Shown += CoverForm_Shown;
        }

        private async void CoverForm_Shown(object? sender, EventArgs e)
        {
            if (Program.CommandLineArgs.Length == 1 && File.Exists(Program.CommandLineArgs[0])) await ShowFileAsync(Program.CommandLineArgs[0]);
        }

        private async void Form_MouseWheel(object? sender, MouseEventArgs e)
        {
            Console.WriteLine("w " + e.Delta);
            if (_currentPath == null) return;
            await NavFile(e.Delta < 0);
        }

        private async void Form_PreviewKeyDown(object? sender, PreviewKeyDownEventArgs e)
        {
            Console.WriteLine($"k {e.KeyCode}");
            if (e.KeyCode == Keys.Escape) _mainForm.Close();

            if (_currentPath == null) return;

            switch (e.KeyCode)
            {
                case Keys.Home:
                    await JumpToFile(true);
                    break;
                case Keys.End:
                    await JumpToFile(false);
                    break;
                case Keys.Space:
                case Keys.Enter:
                case Keys.PageDown:
                    await NavFile(true);
                    break;
                case Keys.Back:
                case Keys.PageUp:
                    await NavFile(false);
                    break;
                case Keys.B:
                    {
                        var src = _currentPath;
                        await NavFile(true);
                        MoveToOuterDotSuffixDir(src, "b");
                        break;
                    }
                case Keys.S:
                    {
                        var src = _currentPath;
                        await NavFile(true);
                        MoveToOuterDotSuffixDir(src, "s");
                        break;
                    }
                case Keys.M:
                    {
                        var src = _currentPath;
                        await NavFile(true);
                        MoveToOuterDotSuffixDir(src, "m");
                        break;
                    }
            }
        }

        private void Form_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data?.GetDataPresent(DataFormats.FileDrop) != true) return;
            if (e.Data.GetData(DataFormats.FileDrop) is not string[] arr) return;
            if (arr.Length == 1 && File.Exists(arr[0])) e.Effect = DragDropEffects.Link;
        }

        private async void Form_DragDrop(object sender, DragEventArgs e)
        {
            if (e.Data?.GetData(DataFormats.FileDrop) is not string[] arr) return;
            if (arr.Length != 1 || !File.Exists(arr[0])) return;
            var path = arr[0];
            await ShowFileAsync(path);
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            var location = _mainForm.PointToScreen(Point.Empty);
            if (Location != location) Location = location;

            var size = _mainForm.ClientSize;
            if (Size != size) Size = size;
        }

        private async Task NavFile(bool isNext)
        {
            if (_currentPath == null) return;
            var nears = GetFilesAround(_currentPath);
            if (nears.Length == 0) return;
            var index = Array.IndexOf(nears, _currentPath);

            if (isNext)
            {
                var lastIndex = nears.Length - 1;

                if (index == lastIndex) return;

                var nextIndex = index + 1;
                if (nextIndex >= nears.Length) nextIndex = lastIndex;

                var next = nears[nextIndex];
                await ShowFileAsync(next);
            }
            else
            {
                if (index > 0)
                {
                    var nextIndex = index - 1;

                    var next = nears[nextIndex];
                    await ShowFileAsync(next);
                }
            }
        }

        private async Task JumpToFile(bool first)
        {
            if (_currentPath == null) return;
            var nears = GetFilesAround(_currentPath);
            if (nears.Length == 0) return;
            var nextIndex = first ? 0 : nears.Length - 1;
            var next = nears[nextIndex];
            await ShowFileAsync(next);
        }

        private async Task ShowFileAsync(string path)
        {
            await _mainForm.webView21.EnsureCoreWebView2Async();

            var nears = GetFilesAround(path);
            if (nears.Length == 0)
            {
                _mainForm.Text = "- no file -";
                _mainForm.webView21.CoreWebView2.Navigate("about:blank");
                _currentPath = null;
                return;
            }

            var index = Array.IndexOf(nears, path);
            _mainForm.Text = $"({nears.Length}/{index + 1}) {path}";
            _mainForm.webView21.CoreWebView2.Navigate("file:///" + path);
            _currentPath = path;
        }

        private void MoveToOuterDotSuffixDir(string src, string s)
        {
            if (File.Exists(src))
            {
                var dir = Path.GetDirectoryName(src);
                var parentDir = Path.GetDirectoryName(dir);
                var name = Path.GetFileName(dir) + "." + s;
                var dstDir = Path.Combine(parentDir, name);
                if (Directory.Exists(dstDir) == false) Directory.CreateDirectory(dstDir);
                var dst = Path.Combine(dstDir, Path.GetFileName(src));
                File.Move(src, dst);
            }

            if (_currentPath == null) return;
            var nears = GetFilesAround(_currentPath);
            var index = Array.IndexOf(nears, _currentPath);
            _mainForm.Text = $"({nears.Length}/{index + 1}) {_currentPath}";
        }

        private static string[] GetFilesAround(string filePath)
        {
            var ext = Path.GetExtension(filePath);
            var dir = Path.GetDirectoryName(filePath);
            return Directory.GetFiles(dir, "*" + ext);
        }
    }
}