unit UUoaDesigns;

{$mode ObjFPC}{$H+}
{$modeSwitch advancedRecords}

interface

uses
  Classes, SysUtils, Generics.Collections, UStatics;

type

  { TUoaDesignHeader }

  TUoaDesignHeader = record
    Name: String;
    Category: String;
    Subcategory: String;
    Width: Int32;
    Height: Int32;
    UserWidth: Int32;
    UserHeight: Int32;
    FilePosition: Int64;
    TileCount: Int32;
  public
    constructor CreateFromStream(AStream: TStream);
  end;

  { TUoaDesignHeaders }

  TUoaDesignHeaders = class(specialize TList<TUoaDesignHeader>)
    constructor CreateFromStream(AStream: TStream);
  end;

  { TUoaDesigns }

  TUoaDesigns = class
  private
    FHeaders: TUoaDesignHeaders;
    FData: TFileStream;
  public
    constructor Create(AIdxFile, ABinFile: String);
    destructor Destroy; override;

    function LoadTiles(AHeader: TUoaDesignHeader; AOffsetX, AOffsetY: Word): TStaticItemList;
  public
    property Headers: TUoaDesignHeaders read FHeaders;
  end;

implementation

function ReadString(AStream: TStream): String;
var
  nonNullFlag: Byte;
  length: Byte;
begin
  nonNullFlag := AStream.ReadByte;
  if nonNullFlag = 1 then
  begin
    length := AStream.ReadByte;
    SetLength(Result, length);
    if length > 0 then
      AStream.Read(PChar(Result)^, length);
  end;
end;

{ TUoaDesignHeaders }

constructor TUoaDesignHeaders.CreateFromStream(AStream: TStream);
var
  headerCount, version: Int32;
  i: Integer;
begin
  AStream.Read(headerCount, SizeOf(headerCount));
  AStream.Read(version, SizeOf(version));

  if version <> 0 then
    raise Exception.Create('Unknown UOA design index version');

  inherited Create;

  for i := 0 to headerCount-1 do
    Add(TUoaDesignHeader.CreateFromStream(AStream));
end;

{ TUoaDesignHeader }

constructor TUoaDesignHeader.CreateFromStream(AStream: TStream);
begin
  Name := ReadString(AStream);
  Category := ReadString(AStream);
  Subcategory := ReadString(AStream);
  AStream.Read(Width, SizeOf(Width));
  AStream.Read(Height, SizeOf(Height));
  AStream.Read(UserWidth, SizeOf(UserWidth));
  AStream.Read(UserHeight, SizeOf(UserHeight));
  AStream.Read(FilePosition, SizeOf(FilePosition));
  AStream.Read(TileCount, SizeOf(TileCount));
end;

{ TUoaDesigns }

constructor TUoaDesigns.Create(AIdxFile, ABinFile: String);
var
  idxStream: TFileStream;
begin
  idxStream := TFileStream.Create(AIdxFile, fmOpenRead);
  try
    FHeaders := TUoaDesignHeaders.CreateFromStream(idxStream);
  finally
    idxStream.Free;
  end;

  FData := TFileStream.Create(ABinFile, fmOpenRead);
end;

destructor TUoaDesigns.Destroy;
begin
  Headers.Free;
end;

function TUoaDesigns.LoadTiles(AHeader: TUoaDesignHeader; AOffsetX,
  AOffsetY: Word): TStaticItemList;
var
  i: Integer;
  tile: TStaticItem;
  version: Int32;

  function ReadInt: Int32;
  begin
    FData.Read(Result, SizeOf(Result));
  end;

begin
  Result := TStaticItemList.Create(True);
  FData.Seek(AHeader.FilePosition, soFromBeginning);
  for i := 0 to AHeader.TileCount - 1 do
  begin
    FData.Read(version, SizeOf(version));
    if (version < 0) or (version > 1) then
      raise Exception.Create('Unsupported binary version');

    tile := TStaticItem.Create(nil);
    tile.TileID := ReadInt;
    tile.X := AOffsetX + ReadInt;
    tile.Y := AOffsetY + ReadInt;
    tile.Z := ReadInt;
    ReadInt; // TODO: Level??

    if version = 1 then
      tile.Hue := ReadInt;

    Result.Add(tile);
  end;
end;

end.