// This file is part of Capy64 - https://github.com/Ale32bit/Capy64
// Copyright 2023 Alessandro "AlexDevs" Proto
//
// Licensed under the Apache License, Version 2.0 (the "License").
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using Capy64.API;
using Capy64.Runtime.Extensions;
using Capy64.Runtime.Objects;
using KeraLua;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace Capy64.Runtime.Libraries;

public class FileSystemLib : IComponent
{
    public static string DataPath = Path.Combine(Capy64.AppDataPath, "data");

    public FileSystemLib()
    {
        if (!Directory.Exists(DataPath))
        {
            Directory.CreateDirectory(DataPath);
        }
    }

    // functions to add to the library, always end libraries with null
    private readonly LuaRegister[] Library = new LuaRegister[] {
        new()
        {
            name = "list",
            function = L_List,
        },
        new()
        {
            name = "combine",
            function = L_Combine,
        },
        new()
        {
            name = "getName",
            function = L_GetPathName,
        },
        new()
        {
            name = "getDir",
            function = L_GetDirectoryName,
        },
        new()
        {
            name = "getSize",
            function = L_GetFileSize,
        },
        new()
        {
            name = "exists",
            function = L_Exists,
        },
        new()
        {
            name = "isReadOnly",
            function = L_IsReadOnly,
        },
        new()
        {
            name = "makeDir",
            function = L_MakeDir,
        },
        new()
        {
            name = "move",
            function = L_Move,
        },
        new()
        {
            name = "copy",
            function = L_Copy,
        },
        new()
        {
            name = "delete",
            function = L_Delete,
        },
        new()
        {
            name = "attributes",
            function = L_GetAttributes,
        },
        new()
        {
            name = "isDir",
            function = L_IsDirectory,
        },
        new()
        {
            name = "open",
            function = L_Open,
        },
        new(), // NULL
    };

    public FileSystemLib(Capy64 _) { }

    public void LuaInit(Lua state)
    {
        // Add "fs" library to lua, not global (uses require())
        state.RequireF("fs", Open, false);
    }

    private int Open(IntPtr state)
    {
        var l = Lua.FromIntPtr(state);
        l.NewLib(Library);
        return 1;
    }

    public static string SanitizePath(string path)
    {
        // Replace \ to / for cross compatibility in case users prefer to use \
        path = path.Replace("\\", "/");

        // Get drive root (C:\ for Windows, / for *nix)
        var rootPath = Path.GetFullPath(Path.GetPathRoot("/") ?? "/");

        // Join path to rootPath and resolves to absolute path
        // Relative paths are resolved here (es. ../ and ./)
        var absolutePath = Path.GetFullPath(path, rootPath);

        // Trim root from path
        string localPath;
        try
        {
            localPath = absolutePath.Remove(0, rootPath.Length);
        }
        catch
        {
            localPath = absolutePath;
        }
        return Path.Join("/", localPath);
    }

    public static string Resolve(string path)
    {
        var isolatedPath = SanitizePath(path);

        // Now join the isolatedPath to the Lua directory, always inside of it
        var resolvedPath = Path.Join(DataPath, isolatedPath);

        return resolvedPath;
    }

    public static string CleanOutputPath(string path)
    {
        if (string.IsNullOrEmpty(path))
            return "";

        var clean = path.Replace(Path.DirectorySeparatorChar, '/');
        return clean;
    }

    public static string TrimBasePath(string path)
    {
        return path;
    }

    public static void CopyDirectory(string sourceDir, string destinationDir, bool recursive, bool overwrite = false)
    {
        var dir = new DirectoryInfo(sourceDir);

        if (!dir.Exists)
            throw new DirectoryNotFoundException($"Source directory not found: {dir.FullName}");

        DirectoryInfo[] dirs = dir.GetDirectories();

        Directory.CreateDirectory(destinationDir);

        foreach (FileInfo file in dir.GetFiles())
        {
            string targetFilePath = Path.Combine(destinationDir, file.Name);
            file.CopyTo(targetFilePath, overwrite);
        }

        if (recursive)
        {
            foreach (DirectoryInfo subDir in dirs)
            {
                string newDestinationDir = Path.Combine(destinationDir, subDir.Name);
                CopyDirectory(subDir.FullName, newDestinationDir, true, overwrite);
            }
        }
    }

    private static int L_List(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = L.CheckString(1);
        path = Resolve(path);

        if (!Directory.Exists(path))
        {
            L.Error("directory not found");
        }

        var fileList = Directory.EnumerateFileSystemEntries(path);

        var list = new List<string>();
        foreach (var file in fileList)
        {
            var sfile = Path.GetFileName(file);
            list.Add(CleanOutputPath(sfile));
        }

        L.PushArray(list.Order().ToArray());

        return 1;
    }

    private static int L_Combine(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var nargs = L.GetTop();

        var parts = new List<string>();
        for (int i = 1; i <= nargs; i++)
        {
            var pathPart = L.CheckString(i);
            parts.Add(pathPart);
        }

        var result = Path.Combine(parts.ToArray());
        if (string.IsNullOrEmpty(result))
        {
            L.PushString("");
            return 1;
        }

        result = SanitizePath(result);
        L.PushString(CleanOutputPath(result));

        return 1;
    }

    private static int L_GetPathName(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = L.CheckString(1);

        var result = Path.GetFileName(path);

        L.PushString(CleanOutputPath(result));

        return 1;
    }

    private static int L_GetDirectoryName(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = L.CheckString(1);

        var result = Path.GetDirectoryName(path);

        L.PushString(CleanOutputPath(result));

        return 1;
    }

    private static int L_GetFileSize(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = L.CheckString(1);

        path = Resolve(path);

        if (!File.Exists(path))
        {
            L.Error("file not found");
        }

        var fileInfo = new FileInfo(path);
        L.PushInteger(fileInfo.Length);

        return 1;
    }

    private static int L_Exists(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = L.CheckString(1);
        var exists = Path.Exists(Resolve(path));

        L.PushBoolean(exists);

        return 1;
    }

    private static int L_IsReadOnly(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);
        var path = Resolve(L.CheckString(1));

        if (File.Exists(path))
        {
            var fileInfo = new FileInfo(path);
            L.PushBoolean(fileInfo.IsReadOnly);
        }
        else if (Directory.Exists(path))
        {
            var dirInfo = new DirectoryInfo(path);
            var isReadOnly = dirInfo.Attributes.HasFlag(FileAttributes.ReadOnly);
            L.PushBoolean(isReadOnly);
        }
        else
        {
            L.Error("path not found");
        }

        return 1;
    }

    private static int L_MakeDir(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = Resolve(L.CheckString(1));

        if (Path.Exists(path))
        {
            L.Error("path already exists");
        }

        Directory.CreateDirectory(path);

        return 0;
    }

    private static int L_Move(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var sourcePath = Resolve(L.CheckString(1));
        var destPath = Resolve(L.CheckString(2));

        if (!Path.Exists(sourcePath))
        {
            L.Error("source path not found");
        }

        if (Path.Exists(destPath))
        {
            L.Error("destination path already exists");
        }

        var attr = File.GetAttributes(sourcePath);
        if (attr.HasFlag(FileAttributes.Directory))
        {
            Directory.Move(sourcePath, destPath);
        }
        else
        {
            File.Move(sourcePath, destPath);
        }

        return 0;
    }

    private static int L_Copy(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var sourcePath = Resolve(L.CheckString(1));
        var destPath = Resolve(L.CheckString(2));

        if (!Path.Exists(sourcePath))
        {
            L.Error("source path not found");
        }

        if (Path.Exists(destPath))
        {
            L.Error("destination path already exists");
        }

        var attr = File.GetAttributes(sourcePath);
        if (attr.HasFlag(FileAttributes.Directory))
        {
            CopyDirectory(sourcePath, destPath, true);
        }
        else
        {
            File.Copy(sourcePath, destPath);
        }

        return 0;
    }

    private static int L_Delete(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = Resolve(L.CheckString(1));
        bool recursive = false;
        if (!L.IsNoneOrNil(2))
        {
            L.CheckType(2, LuaType.Boolean);
            recursive = L.ToBoolean(2);
        }

        if (!Path.Exists(path))
        {
            L.Error("path not found");
        }

        try
        {
            var attr = File.GetAttributes(path);
            if (attr.HasFlag(FileAttributes.Directory))
            {
                if (!recursive && Directory.GetFileSystemEntries(path).Any())
                {
                    L.Error("directory not empty");
                    return 0;
                }
                Directory.Delete(path, recursive);
            }
            else
            {
                File.Delete(path);
            }
        }
        catch (Exception e)
        {
            return L.Error(e.Message);
        }

        return 0;
    }

    private static int L_GetAttributes(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = Resolve(L.CheckString(1));

        // { size = number, isDir = boolean, isReadOnly = boolean, created = number, modified = number }
        if (!Path.Exists(path))
        {
            L.Error("path not found");
        }

        var attributes = new Dictionary<string, object>();

        var pathAttributes = File.GetAttributes(path);
        if (pathAttributes.HasFlag(FileAttributes.Directory))
        {
            var dattrs = new DirectoryInfo(path);
            attributes["size"] = 0;
            attributes["isDirectory"] = true;
            attributes["isReadOnly"] = dattrs.Attributes.HasFlag(FileAttributes.ReadOnly);
            attributes["created"] = new DateTimeOffset(dattrs.CreationTimeUtc).ToUnixTimeMilliseconds();
            attributes["modified"] = new DateTimeOffset(dattrs.LastWriteTimeUtc).ToUnixTimeMilliseconds();
        }
        else
        {
            var fattrs = new FileInfo(path);
            attributes["size"] = fattrs.Length;
            attributes["isDirectory"] = false;
            attributes["isReadOnly"] = fattrs.IsReadOnly;
            attributes["created"] = new DateTimeOffset(fattrs.CreationTimeUtc).ToUnixTimeMilliseconds();
            attributes["modified"] = new DateTimeOffset(fattrs.LastWriteTimeUtc).ToUnixTimeMilliseconds();
        }

        L.NewTable();

        foreach (var attribute in attributes)
        {
            L.PushString(attribute.Key);
            L.PushValue(attribute.Value);

            L.SetTable(-3);
        }

        return 1;
    }

    private static int L_IsDirectory(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);

        var path = Resolve(L.CheckString(1));

        L.PushBoolean(Directory.Exists(path));

        return 1;
    }

    private static int L_Open(IntPtr state)
    {
        var L = Lua.FromIntPtr(state);
        var path = Resolve(L.CheckString(1));
        var mode = L.OptString(2, "r");

        var errorMessage = "invalid file mode";
        if (mode.Length < 1)
        {
            L.ArgumentError(2, errorMessage);
            return 0;
        }

        FileMode fileMode;
        FileAccess fileAccess;
        switch (mode[0])
        {
            case 'r':
                if (!File.Exists(path))
                {
                    L.Error("file not found");
                    return 0;
                }
                fileMode = FileMode.Open;
                fileAccess = FileAccess.Read;
                break;
            case 'w':
                fileMode = FileMode.Create;
                fileAccess = FileAccess.Write;
                break;
            case 'a':
                fileMode = FileMode.Append;
                fileAccess = FileAccess.Write;
                break;
            default:
                L.ArgumentError(2, errorMessage);
                return 0;
        }

        try
        {
            var fileStream = File.Open(path, fileMode, fileAccess, FileShare.ReadWrite | FileShare.Delete);

            ObjectManager.PushObject(L, fileStream);
            L.SetMetaTable(FileHandle.ObjectType);

            return 1;
        }
        catch (Exception ex)
        {
            L.Error(ex.Message);
        }
        return 0;
    }

}