using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
using PKHeX.Core;

namespace PKHeX.WinForms
{
    public partial class TrashEditor : Form
    {
        private readonly SaveFile SAV;

        public TrashEditor(TextBoxBase TB_NN, SaveFile sav) : this(TB_NN, Array.Empty<byte>(), sav) { }

        public TrashEditor(TextBoxBase TB_NN, Span<byte> raw, SaveFile sav)
        {
            InitializeComponent();
            WinFormsUtil.TranslateInterface(this, Main.CurrentLanguage);
            SAV = sav;

            FinalString = TB_NN.Text;
            Raw = FinalBytes = raw.ToArray();

            editing = true;
            if (raw.Length != 0)
                AddTrashEditing(raw.Length);

            var f = FontUtil.GetPKXFont();
            AddCharEditing(f);
            TB_Text.MaxLength = TB_NN.MaxLength;
            TB_Text.Text = TB_NN.Text;
            TB_Text.Font = f;

            if (FLP_Characters.Controls.Count == 0)
            {
                FLP_Characters.Visible = false;
                FLP_Hex.Height *= 2;
            }
            else if (FLP_Hex.Controls.Count == 0)
            {
                FLP_Characters.Location = FLP_Hex.Location;
                FLP_Characters.Height *= 2;
            }

            editing = false;
            CenterToParent();
        }

        private readonly List<NumericUpDown> Bytes = new();
        public string FinalString;
        public byte[] FinalBytes;
        private readonly byte[] Raw;
        private bool editing;
        private void B_Cancel_Click(object sender, EventArgs e) => Close();

        private void B_Save_Click(object sender, EventArgs e)
        {
            FinalString = TB_Text.Text;
            if (FinalBytes.Length == 0)
                FinalBytes = Raw;
            Close();
        }

        private void AddCharEditing(Font f)
        {
            ushort[] chars = GetChars(SAV.Generation);
            if (chars.Length == 0)
                return;

            FLP_Characters.Visible = true;
            foreach (ushort c in chars)
            {
                var l = GetLabel(((char)c).ToString());
                l.Font = f;
                l.AutoSize = false;
                l.Size = new Size(20, 20);
                l.Click += (s, e) => { if (TB_Text.Text.Length < TB_Text.MaxLength) TB_Text.AppendText(l.Text); };
                FLP_Characters.Controls.Add(l);
            }
        }

        private void AddTrashEditing(int count)
        {
            FLP_Hex.Visible = true;
            GB_Trash.Visible = true;
            NUD_Generation.Value = SAV.Generation;
            for (int i = 0; i < count; i++)
            {
                var l = GetLabel($"${i:X2}");
                l.Font = NUD_Generation.Font;
                var n = GetNUD(min: 0, max: 255, hex: true);
                n.Click += (s, e) =>
                {
                    switch (ModifierKeys)
                    {
                        case Keys.Shift: n.Value = n.Maximum; break;
                        case Keys.Alt: n.Value = n.Minimum; break;
                    }
                };
                n.Value = Raw[i];
                n.ValueChanged += (o, args) => UpdateNUD(n, args);

                FLP_Hex.Controls.Add(l);
                FLP_Hex.Controls.Add(n);
                Bytes.Add(n);
            }
            TB_Text.TextChanged += (o, args) => UpdateString(TB_Text, args);

            CB_Species.InitializeBinding();
            CB_Species.DataSource = new BindingSource(GameInfo.SpeciesDataSource, null);

            CB_Language.InitializeBinding();
            CB_Language.DataSource = GameInfo.LanguageDataSource(SAV.Generation);
        }

        private void UpdateNUD(object sender, EventArgs e)
        {
            if (editing)
                return;
            editing = true;
            // build bytes
            if (sender is not NumericUpDown nud)
                throw new Exception();
            int index = Bytes.IndexOf(nud);
            Raw[index] = (byte)nud.Value;

            TB_Text.Text = GetString();
            editing = false;
        }

        private void UpdateString(object sender, EventArgs e)
        {
            if (editing)
                return;
            editing = true;
            // build bytes
            byte[] data = SetString(TB_Text.Text);
            Array.Copy(data, Raw, Math.Min(data.Length, Raw.Length));
            for (int i = 0; i < Raw.Length; i++)
                Bytes[i].Value = Raw[i];
            editing = false;
        }

        private void B_ApplyTrash_Click(object sender, EventArgs e)
        {
            string species = SpeciesName.GetSpeciesNameGeneration(WinFormsUtil.GetIndex(CB_Species),
                WinFormsUtil.GetIndex(CB_Language), (int) NUD_Generation.Value);

            if (string.IsNullOrEmpty(species)) // no result
                species = CB_Species.Text;

            byte[] current = SetString(TB_Text.Text);
            byte[] data = SetString(species);
            if (data.Length <= current.Length)
            {
                WinFormsUtil.Alert("Trash byte layer is hidden by current text.",
                    $"Current Bytes: {current.Length}" + Environment.NewLine + $"Layer Bytes: {data.Length}");
                return;
            }
            if (data.Length > Bytes.Count)
            {
                WinFormsUtil.Alert("Trash byte layer is too long to apply.");
                return;
            }
            for (int i = current.Length; i < data.Length; i++)
                Bytes[i].Value = data[i];
        }

        private void B_ClearTrash_Click(object sender, EventArgs e)
        {
            byte[] current = SetString(TB_Text.Text);
            for (int i = current.Length; i < Bytes.Count; i++)
                Bytes[i].Value = 0;
        }

        private byte[] SetString(string text)
        {
            Span<byte> temp = stackalloc byte[Raw.Length];
            var written = SAV.SetString(temp, text.AsSpan(), text.Length, StringConverterOption.None);
            return temp[..written].ToArray();
        }

        private string GetString() => SAV.GetString(Raw.AsSpan());

        // Helpers
        private static Label GetLabel(string str) => new() {Text = str, AutoSize = true};

        private static NumericUpDown GetNUD(int min, int max, bool hex) => new()
        {
            Maximum = max,
            Minimum = min,
            Hexadecimal = hex,
            Width = 36,
            Padding = new Padding(0),
            Margin = new Padding(0),
        };

        private static ushort[] GetChars(int generation) => generation switch
        {
            6 => chars67,
            7 => chars67,
            _ => Array.Empty<ushort>(), // Undocumented
        };

        private static readonly ushort[] chars67 =
        {
            0xE081, 0xE082, 0xE083, 0xE084, 0xE085, 0xE086, 0xE087, 0xE08D,
            0xE08E, 0xE08F, 0xE090, 0xE091, 0xE092, 0xE093, 0xE094, 0xE095,
            0xE096, 0xE097, 0xE098, 0xE099, 0xE09A, 0xE09B, 0xE09C, 0xE09D,
            0xE09E, 0xE09F, 0xE0A0, 0xE0A1, 0xE0A2, 0xE0A3, 0xE0A4, 0xE0A5,
        };
    }
}