program JsonReadWrite2;

{$mode objfpc}{$H+}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  Classes { you can add units after this },
  SysUtils,
  fpjson,
  jsonparser;

type
  { 各アイテムのデータを保持するレコード型 }
  TMyRecord = record
    Name: string;
    Path: string;
    Args: string;
  end;

  { 配列アクセス用の型定義 }
  TMyRecordArray = array of TMyRecord;

  { 設定管理クラス }
  TMyConfig = class(TPersistent)
  private
    FItems: TMyRecordArray;
    FIndexed: integer;
    function GetItem(Index: integer): TMyRecord;
    procedure SetItem(Index: integer; const AValue: TMyRecord);
  public
    constructor Create;
    destructor Destroy; override;

    { --- JSON & ファイル操作 --- }
    function ToJsonString: string;
    procedure FromJsonString(const AJsonStr: string);
    procedure SaveToFile(const AFileName: string);
    procedure LoadFromFile(const AFileName: string);

    { --- データ操作メソッド (CRUD) --- }
    procedure AddItem(const AName, APath, AArgs: string);
    procedure UpdateItem(Index: integer; const AName, APath, AArgs: string);
    procedure RemoveItem(Index: integer);
    procedure ClearItems;
    function Count: integer;

    { --- 表示用プロシージャ --- }
    procedure PrintAll(const Msg: string);

    { --- プロパティ --- }
    property Items[Index: integer]: TMyRecord read GetItem write SetItem; default;
    property Indexed: integer read FIndexed write FIndexed;
  end;

  { --- TMyConfig クラスの実装 --- }

constructor TMyConfig.Create;
begin
  inherited Create;
  FIndexed := 0;
  SetLength(FItems, 0);
end;

destructor TMyConfig.Destroy;
begin
  SetLength(FItems, 0);
  inherited Destroy;
end;

function TMyConfig.GetItem(Index: integer): TMyRecord;
begin
  if (Index >= 0) and (Index < Length(FItems)) then
    Result := FItems[Index]
  else
    raise Exception.CreateFmt('Error: Index %d is out of bounds.', [Index]);
end;

procedure TMyConfig.SetItem(Index: integer; const AValue: TMyRecord);
begin
  if (Index >= 0) and (Index < Length(FItems)) then
    FItems[Index] := AValue
  else
    raise Exception.CreateFmt('Error: Index %d is out of bounds.', [Index]);
end;

procedure TMyConfig.AddItem(const AName, APath, AArgs: string);
var
  NewIdx: integer;
begin
  NewIdx := Length(FItems);
  SetLength(FItems, NewIdx + 1);
  FItems[NewIdx].Name := AName;
  FItems[NewIdx].Path := APath;
  FItems[NewIdx].Args := AArgs;
end;

procedure TMyConfig.UpdateItem(Index: integer; const AName, APath, AArgs: string);
begin
  if (Index >= 0) and (Index < Length(FItems)) then
  begin
    FItems[Index].Name := AName;
    FItems[Index].Path := APath;
    FItems[Index].Args := AArgs;
  end
  else
    raise Exception.CreateFmt('Error: Index %d is out of bounds for UpdateItem.',
      [Index]);
end;

procedure TMyConfig.RemoveItem(Index: integer);
begin
  if (Index >= 0) and (Index < Length(FItems)) then
  begin
    Delete(FItems, Index, 1);
  end
  else
    raise Exception.CreateFmt('Error: Index %d is out of bounds for RemoveItem.',
      [Index]);
end;

procedure TMyConfig.ClearItems;
begin
  SetLength(FItems, 0);
end;

function TMyConfig.Count: integer;
begin
  Result := Length(FItems);
end;

{ 一覧を出力するプロシージャ }
procedure TMyConfig.PrintAll(const Msg: string);
var
  i: integer;
begin
  WriteLn('--- ', Msg, ' ---');
  WriteLn(Format('Indexed: %d, Total Items: %d', [FIndexed, Count]));

  if Count = 0 then
    WriteLn('(No items)')
  else
  begin
    for i := 0 to Count - 1 do
    begin
      { Format関数を使って綺麗に整列させて出力 }
      WriteLn(Format('[%d] Name: %-15s | Path: %-20s | Args: %s',
        [i, FItems[i].Name, FItems[i].Path, FItems[i].Args]));
    end;
  end;
  WriteLn('----------------------------');
  WriteLn;
end;

function TMyConfig.ToJsonString: string;
var
  Root, ItemObj: TJSONObject;
  ItemsArr: TJSONArray;
  i: integer;
begin
  Root := TJSONObject.Create;
  try
    Root.Add('Indexed', FIndexed);
    ItemsArr := TJSONArray.Create;
    for i := 0 to High(FItems) do
    begin
      ItemObj := TJSONObject.Create;
      ItemObj.Add('Name', FItems[i].Name);
      ItemObj.Add('Path', FItems[i].Path);
      ItemObj.Add('Args', FItems[i].Args);
      ItemsArr.Add(ItemObj);
    end;
    Root.Add('Items', ItemsArr);
    Result := Root.FormatJSON;
  finally
    Root.Free;
  end;
end;

procedure TMyConfig.FromJsonString(const AJsonStr: string);
var
  JSONData: TJSONData;
  Root: TJSONObject;
  ItemsArr: TJSONArray;
  i: integer;
begin
  JSONData := GetJSON(AJsonStr);
  try
    if JSONData is TJSONObject then
    begin
      Root := TJSONObject(JSONData);
      FIndexed := Root.Get('Indexed', 0);

      if Root.Find('Items', JSONData) and (JSONData is TJSONArray) then
      begin
        ItemsArr := TJSONArray(JSONData);
        SetLength(FItems, ItemsArr.Count);
        for i := 0 to ItemsArr.Count - 1 do
        begin
          FItems[i].Name := ItemsArr.Objects[i].Get('Name', '');
          FItems[i].Path := ItemsArr.Objects[i].Get('Path', '');
          FItems[i].Args := ItemsArr.Objects[i].Get('Args', '');
        end;
      end;
    end;
  finally
    JSONData.Free;
  end;
end;

procedure TMyConfig.SaveToFile(const AFileName: string);
var
  L: TStringList;
begin
  L := TStringList.Create;
  try
    L.Text := ToJsonString;
    L.SaveToFile(AFileName);
  finally
    L.Free;
  end;
end;

procedure TMyConfig.LoadFromFile(const AFileName: string);
var
  L: TStringList;
begin
  if not FileExists(AFileName) then exit;
  L := TStringList.Create;
  try
    L.LoadFromFile(AFileName);
    FromJsonString(L.Text);
  finally
    L.Free;
  end;
end;

{ --- メインプログラム --- }

var
  Config: TMyConfig;
  FileName: string = 'settings.json';
begin
  Config := TMyConfig.Create;
  try
    { 1. 初期データの追加テスト }
    Config.AddItem('Lazarus', '/usr/bin/lazarus', '--version');
    Config.AddItem('Calculator', 'calc.exe', '');
    Config.AddItem('Notepad', 'notepad.exe', 'readme.txt');
    Config.Indexed := 100;
    Config.PrintAll('After Adding Items');

    { 2. 更新テスト }
    Config.UpdateItem(0, 'Lazarus IDE', '/opt/lazarus', '--debug');
    Config.PrintAll('After Updating Item[0]');

    { 3. 削除テスト }
    Config.RemoveItem(1); // Calculator を削除
    Config.PrintAll('After Removing Item[1]');

    { 4. ファイル保存と読み込みテスト }
    WriteLn('Saving to file: ', FileName);
    Config.SaveToFile(FileName);

    Config.ClearItems;
    Config.PrintAll('After Clear (Memory Empty)');

    WriteLn('Loading from file...');
    Config.LoadFromFile(FileName);
    Config.PrintAll('After Loading from File');

  except
    on E: Exception do
      WriteLn('Error: ', E.Message);
  end;

  Config.Free;
  WriteLn('Press Enter to quit.');
  ReadLn;
end.