using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Windows.Forms;
using PKHeX.Core;
using PKHeX.WinForms.Controls;
using static PKHeX.Core.MessageStrings;

namespace PKHeX.WinForms;

public partial class BatchEditor : Form
{
    private readonly SaveFile SAV;

    // Mass Editing
    private Core.BatchEditor editor = new();
    private readonly EntityInstructionBuilder UC_Builder;

    private static string LastUsedCommands = string.Empty;

    public BatchEditor(PKM pk, SaveFile sav)
    {
        InitializeComponent();
        WinFormsUtil.TranslateInterface(this, Main.CurrentLanguage);
        var above = FLP_RB.Location;
        UC_Builder = new EntityInstructionBuilder(() => pk)
        {
            Location = new() { Y = above.Y + FLP_RB.Height + 4 - 1, X = above.X + 1 },
            Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right,
            Width = B_Add.Location.X - above.X - 2,
        };
        Controls.Add(UC_Builder);
        SAV = sav;
        DragDrop += TabMain_DragDrop;
        DragEnter += TabMain_DragEnter;

        RTB_Instructions.Text = LastUsedCommands;
        Closing += (_, _) => LastUsedCommands = RTB_Instructions.Text;
    }

    private void B_Open_Click(object sender, EventArgs e)
    {
        if (!B_Go.Enabled)
            return;
        using var fbd = new FolderBrowserDialog();
        if (fbd.ShowDialog() != DialogResult.OK)
            return;

        TB_Folder.Text = fbd.SelectedPath;
        TB_Folder.Visible = true;
    }

    private void B_SAV_Click(object sender, EventArgs e)
    {
        TB_Folder.Text = string.Empty;
        TB_Folder.Visible = false;
    }

    private void B_Go_Click(object sender, EventArgs e)
    {
        RunBackgroundWorker();
    }

    private void B_Add_Click(object sender, EventArgs e)
    {
        var s = UC_Builder.Create();
        if (s.Length == 0)
        { WinFormsUtil.Alert(MsgBEPropertyInvalid); return; }

        // If we already have text, add a new line (except if the last line is blank).
        var tb = RTB_Instructions;
        var batchText = tb.Text;
        if (batchText.Length != 0 && !batchText.EndsWith('\n'))
            tb.AppendText(Environment.NewLine);
        RTB_Instructions.AppendText(s);
    }

    private static void TabMain_DragEnter(object? sender, DragEventArgs? e)
    {
        if (e?.Data is null)
            return;
        if (e.Data.GetDataPresent(DataFormats.FileDrop))
            e.Effect = DragDropEffects.Copy;
    }

    private void TabMain_DragDrop(object? sender, DragEventArgs? e)
    {
        if (e?.Data?.GetData(DataFormats.FileDrop) is not string[] { Length: not 0 } files)
            return;
        if (!Directory.Exists(files[0]))
            return;

        TB_Folder.Text = files[0];
        TB_Folder.Visible = true;
        RB_Boxes.Checked = RB_Party.Checked = false;
        RB_Path.Checked = true;
    }

    private void RunBackgroundWorker()
    {
        ReadOnlySpan<char> text = RTB_Instructions.Text;
        if (StringInstructionSet.HasEmptyLine(text))
        { WinFormsUtil.Error(MsgBEInstructionInvalid); return; }

        var sets = StringInstructionSet.GetBatchSets(text);
        if (Array.Exists(sets, s => s.Filters.Any(z => string.IsNullOrWhiteSpace(z.PropertyValue))))
        { WinFormsUtil.Error(MsgBEFilterEmpty); return; }

        if (Array.Exists(sets, z => z.Instructions.Count == 0))
        { WinFormsUtil.Error(MsgBEInstructionNone); return; }

        var emptyVal = sets.SelectMany(s => s.Instructions.Where(z => string.IsNullOrWhiteSpace(z.PropertyValue))).ToArray();
        if (emptyVal.Length != 0)
        {
            string props = string.Join(", ", emptyVal.Select(z => z.PropertyName));
            string invalid = MsgBEPropertyEmpty + Environment.NewLine + props;
            if (DialogResult.Yes != WinFormsUtil.Prompt(MessageBoxButtons.YesNo, invalid, MsgContinue))
                return;
        }

        string? destPath = null;
        if (RB_Path.Checked)
        {
            WinFormsUtil.Alert(MsgExportFolder, MsgExportFolderAdvice);
            using var fbd = new FolderBrowserDialog();
            var dr = fbd.ShowDialog();
            if (dr != DialogResult.OK)
                return;

            destPath = fbd.SelectedPath;
        }

        FLP_RB.Enabled = RTB_Instructions.Enabled = B_Go.Enabled = false;

        foreach (var set in sets)
        {
            BatchEditing.ScreenStrings(set.Filters);
            BatchEditing.ScreenStrings(set.Instructions);
        }
        RunBatchEdit(sets, TB_Folder.Text, destPath);
    }

    private void RunBatchEdit(StringInstructionSet[] sets, string source, string? destination)
    {
        editor = new Core.BatchEditor();
        bool finished = false, displayed = false; // hack cuz DoWork event isn't cleared after completion
        b.DoWork += (_, _) =>
        {
            if (finished)
                return;
            if (RB_Boxes.Checked)
                RunBatchEditSaveFile(sets, boxes: true);
            else if (RB_Party.Checked)
                RunBatchEditSaveFile(sets, party: true);
            else if (destination is not null)
                RunBatchEditFolder(sets, source, destination);
            finished = true;
        };
        b.ProgressChanged += (_, e) => SetProgressBar(e.ProgressPercentage);
        b.RunWorkerCompleted += (_, _) =>
        {
            string result = editor.GetEditorResults(sets);
            if (!displayed) WinFormsUtil.Alert(result);
            displayed = true;
            FLP_RB.Enabled = RTB_Instructions.Enabled = B_Go.Enabled = true;
            SetupProgressBar(0);
        };
        b.RunWorkerAsync();
    }

    private void RunBatchEditFolder(IReadOnlyCollection<StringInstructionSet> sets, string source, string destination)
    {
        var files = Directory.GetFiles(source, "*", SearchOption.AllDirectories);
        SetupProgressBar(files.Length * sets.Count);
        foreach (var set in sets)
            ProcessFolder(files, destination, set.Filters, set.Instructions);
    }

    private void RunBatchEditSaveFile(IReadOnlyCollection<StringInstructionSet> sets, bool boxes = false, bool party = false)
    {
        if (party)
        {
            var data = new List<SlotCache>(SAV.PartyCount);
            SlotInfoLoader.AddPartyData(SAV, data);
            process(data);
            foreach (var slot in data)
                slot.Source.WriteTo(SAV, slot.Entity, EntityImportSettings.None);
        }
        if (boxes)
        {
            var data = new List<SlotCache>(SAV.SlotCount);
            SlotInfoLoader.AddBoxData(SAV, data);
            process(data);
            foreach (var slot in data)
                slot.Source.WriteTo(SAV, slot.Entity, EntityImportSettings.None);
        }
        void process(IList<SlotCache> d)
        {
            SetupProgressBar(d.Count * sets.Count);
            foreach (var set in sets)
                ProcessSAV(d, set.Filters, set.Instructions);
        }
    }

    // Progress Bar
    private void SetupProgressBar(int count) => PB_Show.BeginInvoke(() =>
    {
        PB_Show.Minimum = 0;
        PB_Show.Step = 1;
        PB_Show.Value = 0;
        PB_Show.Maximum = count;
    });

    private void SetProgressBar(int position) => PB_Show.BeginInvoke(() => PB_Show.Value = position);

    private void ProcessSAV(IList<SlotCache> data, IReadOnlyList<StringInstruction> Filters, IReadOnlyList<StringInstruction> Instructions)
    {
        if (data.Count == 0)
            return;

        // Pull out any filter meta instructions from the filters.
        var filterMeta = Filters.Where(f => BatchFilters.FilterMeta.Any(z => z.IsMatch(f.PropertyName))).ToArray();
        if (filterMeta.Length != 0)
            Filters = Filters.Except(filterMeta).ToArray();

        var max = SAV.MaxSpeciesID;

        for (int i = 0; i < data.Count; i++)
        {
            var entry = data[i];
            var pk = entry.Entity;

            // Ignore empty/invalid slots.
            var spec = pk.Species;
            if (spec == 0 || spec > max)
            {
                b.ReportProgress(i);
                continue;
            }

            if (entry.Source is SlotInfoBox info && SAV.GetBoxSlotFlags(info.Box, info.Slot).IsOverwriteProtected())
                editor.AddSkipped();
            else if (!BatchEditing.IsFilterMatchMeta(filterMeta, entry))
                editor.AddSkipped();
            else
                editor.Process(pk, Filters, Instructions);

            b.ReportProgress(i);
        }
    }

    private void ProcessFolder(IReadOnlyList<string> files, string destDir, IReadOnlyList<StringInstruction> pkFilters, IReadOnlyList<StringInstruction> instructions)
    {
        var filterMeta = pkFilters.Where(f => BatchFilters.FilterMeta.Any(z => z.IsMatch(f.PropertyName))).ToArray();
        if (filterMeta.Length != 0)
            pkFilters = pkFilters.Except(filterMeta).ToArray();

        for (int i = 0; i < files.Count; i++)
        {
            TryProcess(files[i], destDir, filterMeta, pkFilters, instructions);
            b.ReportProgress(i);
        }
    }

    private void TryProcess(string source, string destDir, IReadOnlyList<StringInstruction> metaFilters, IReadOnlyList<StringInstruction> pkFilters, IReadOnlyList<StringInstruction> instructions)
    {
        var fi = new FileInfo(source);
        if (!EntityDetection.IsSizePlausible(fi.Length))
            return;

        byte[] data = File.ReadAllBytes(source);
        _ = FileUtil.TryGetPKM(data, out var pk, fi.Extension, SAV);
        if (pk is null)
            return;

        var info = new SlotInfoFileSingle(source);
        var entry = new SlotCache(info, pk);
        if (!BatchEditing.IsFilterMatchMeta(metaFilters, entry))
        {
            editor.AddSkipped();
            return;
        }

        if (editor.Process(pk, pkFilters, instructions))
            File.WriteAllBytes(Path.Combine(destDir, Path.GetFileName(source)), pk.DecryptedPartyData);
    }
}
