unit KaMGeneratedTerrainBridge;

interface

uses
  KM_ResTypes, KM_ResTilesetTypes;

type
  TKaMGeneratedTerrainInfoQuery = function(aTerrain: Integer): TKMGenTerrainInfo of object;
  TKaMGeneratedTerrainTransitionQuery = function(
    aTerKind: TKMTerrainKind;
    aMaskKind: TKMTileMaskKind;
    aMaskType: TKMTileMaskType;
    aMaskSubtype: TKMTileMaskSubType
  ): Word of object;

function KaMGeneratedTerrainInfo(aTerrain: Integer): TKMGenTerrainInfo;
function KaMGeneratedTerrainInfoLegacy(aTerrain: Integer): TKMGenTerrainInfo;
function KaMGeneratedTerrainTransition(
  aTerKind: TKMTerrainKind;
  aMaskKind: TKMTileMaskKind;
  aMaskType: TKMTileMaskType;
  aMaskSubtype: TKMTileMaskSubType
): Word;

procedure KaMPublishGeneratedTerrainProvider(
  aOwner: TObject;
  aCurrentInfo: TKaMGeneratedTerrainInfoQuery;
  aLegacyInfo: TKaMGeneratedTerrainInfoQuery;
  aTransition: TKaMGeneratedTerrainTransitionQuery
);
procedure KaMUnpublishGeneratedTerrainProvider(aOwner: TObject);

implementation

uses
  SysUtils;

var
  GProviderOwner: TObject;
  GCurrentInfoQuery: TKaMGeneratedTerrainInfoQuery;
  GLegacyInfoQuery: TKaMGeneratedTerrainInfoQuery;
  GTransitionQuery: TKaMGeneratedTerrainTransitionQuery;

procedure ClearGeneratedTerrainProvider;
begin
  GProviderOwner := nil;
  GCurrentInfoQuery := nil;
  GLegacyInfoQuery := nil;
  GTransitionQuery := nil;
end;

procedure RequireGeneratedTerrainProvider;
begin
  if (GProviderOwner = nil)
    or not Assigned(GCurrentInfoQuery)
    or not Assigned(GLegacyInfoQuery)
    or not Assigned(GTransitionQuery) then
    raise Exception.Create('Generated-terrain provider is unavailable');
end;

function KaMGeneratedTerrainInfo(aTerrain: Integer): TKMGenTerrainInfo;
begin
  RequireGeneratedTerrainProvider;
  Result := GCurrentInfoQuery(aTerrain);
end;

function KaMGeneratedTerrainInfoLegacy(aTerrain: Integer): TKMGenTerrainInfo;
begin
  RequireGeneratedTerrainProvider;
  Result := GLegacyInfoQuery(aTerrain);
end;

function KaMGeneratedTerrainTransition(
  aTerKind: TKMTerrainKind;
  aMaskKind: TKMTileMaskKind;
  aMaskType: TKMTileMaskType;
  aMaskSubtype: TKMTileMaskSubType
): Word;
begin
  RequireGeneratedTerrainProvider;
  Result := GTransitionQuery(aTerKind, aMaskKind, aMaskType, aMaskSubtype);
end;

procedure KaMPublishGeneratedTerrainProvider(
  aOwner: TObject;
  aCurrentInfo: TKaMGeneratedTerrainInfoQuery;
  aLegacyInfo: TKaMGeneratedTerrainInfoQuery;
  aTransition: TKaMGeneratedTerrainTransitionQuery
);
begin
  if (aOwner = nil)
    or not Assigned(aCurrentInfo)
    or not Assigned(aLegacyInfo)
    or not Assigned(aTransition) then
    raise Exception.Create('Generated-terrain provider binding is incomplete');

  GProviderOwner := aOwner;
  GCurrentInfoQuery := aCurrentInfo;
  GLegacyInfoQuery := aLegacyInfo;
  GTransitionQuery := aTransition;
end;

procedure KaMUnpublishGeneratedTerrainProvider(aOwner: TObject);
begin
  if (aOwner <> nil) and (aOwner = GProviderOwner) then
    ClearGeneratedTerrainProvider;
end;

end.