/*****************************************************************************

gifclrmap - extract colormaps from GIF images

SPDX-License-Identifier: MIT

*****************************************************************************/

#include <assert.h>
#include <ctype.h>
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "getarg.h"
#include "gif_lib.h"

#define PROGRAM_NAME "gifclrmp"

static char *VersionStr = PROGRAM_NAME VERSION_COOKIE
    "	Gershon Elber,	" __DATE__ ",   " __TIME__ "\n"
    "(C) Copyright 1989 Gershon Elber.\n";
static char *CtrlStr =
    PROGRAM_NAME " v%- s%- t%-TranslationFile!s l%-ColorMapFile!s g%-Gamma!F "
                 "i%-Image#!d h%- GifFile!*s";

static bool SaveFlag = false, TranslateFlag = false, LoadFlag = false,
            GammaFlag = false;
static double Gamma = 1.0;
static FILE *ColorFile = NULL;
FILE *TranslateFile = NULL;
static GifPixelType Translation[256];

static ColorMapObject *ModifyColorMap(ColorMapObject *ColorMap);
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut);

/******************************************************************************
 Interpret the command line and scan the given GIF file.
******************************************************************************/
int main(int argc, char **argv) {
	int NumFiles, ExtCode, CodeSize, ImageNum = 0, ImageN, HasGIFOutput,
	                                 ErrorCode;
	bool Error, ImageNFlag = false, HelpFlag = false, GifNoisyPrint = false;
	GifRecordType RecordType;
	GifByteType *Extension, *CodeBlock;
	char **FileName = NULL, *ColorFileName, *TranslateFileName;
	GifFileType *GifFileIn = NULL, *GifFileOut = NULL;

	if ((Error = GAGetArgs(argc, argv, CtrlStr, &GifNoisyPrint, &SaveFlag,
	                       &TranslateFlag, &TranslateFileName, &LoadFlag,
	                       &ColorFileName, &GammaFlag, &Gamma, &ImageNFlag,
	                       &ImageN, &HelpFlag, &NumFiles, &FileName)) !=
	        false ||
	    (NumFiles > 1 && !HelpFlag)) {
		if (Error) {
			GAPrintErrMsg(Error);
		} else if (NumFiles > 1) {
			GIF_MESSAGE("Error in command line parsing - one GIF "
			            "file please.");
		}
		GAPrintHowTo(CtrlStr);
		exit(EXIT_FAILURE);
	}

	if (HelpFlag) {
		(void)fprintf(stderr, VersionStr, GIFLIB_MAJOR, GIFLIB_MINOR);
		GAPrintHowTo(CtrlStr);
		exit(EXIT_SUCCESS);
	}

	if (SaveFlag + LoadFlag + GammaFlag + TranslateFlag > 1) {
		GIF_EXIT("Can not handle more than one of -s -l, -t, or -g at "
		         "the same time.");
	}

	/* Default action is to dump colormaps */
	if (!SaveFlag && !LoadFlag && !GammaFlag && !TranslateFlag) {
		SaveFlag = true;
	}

	if (NumFiles == 1) {
		if ((GifFileIn = DGifOpenFileName(*FileName, &ErrorCode)) ==
		    NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	} else {
		/* Use stdin instead: */
		if ((GifFileIn = DGifOpenFileHandle(0, &ErrorCode)) == NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	}

	if (SaveFlag) {
		/* We are dumping out the color map as text file to stdout: */
		ColorFile = stdout;
	} else {
		if (TranslateFlag) {
			/* We are loading new color map from specified file: */
			if ((TranslateFile = fopen(TranslateFileName, "rt")) ==
			    NULL) {
				GIF_EXIT("Failed to open specified color "
				         "translation file.");
			}
		}

		if (LoadFlag) {
			/* We are loading new color map from specified file: */
			if ((ColorFile = fopen(ColorFileName, "rt")) == NULL) {
				GIF_EXIT(
				    "Failed to open specified color map file.");
			}
		}
	}

	if ((HasGIFOutput = (LoadFlag || TranslateFlag || GammaFlag)) != 0) {
		/* Open stdout for GIF output file: */
		if ((GifFileOut = EGifOpenFileHandle(1, &ErrorCode)) == NULL) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	}

	if (!ImageNFlag) {
		/* We are supposed to modify the screen color map, so do it: */
		if (!GifFileIn->SColorMap) {
			GIF_EXIT("No colormap to modify");
		}
		GifFileIn->SColorMap = ModifyColorMap(GifFileIn->SColorMap);
		if (!HasGIFOutput) {
			/* We can quit here, as we have the color map: */
			DGifCloseFile(GifFileIn, NULL);
			fclose(ColorFile);
			exit(EXIT_SUCCESS);
		}
	}
	/* And dump out its new possible repositioned screen information: */
	if (HasGIFOutput) {
		if (EGifPutScreenDesc(GifFileOut, GifFileIn->SWidth,
		                      GifFileIn->SHeight,
		                      GifFileIn->SColorResolution,
		                      GifFileIn->SBackGroundColor,
		                      GifFileIn->SColorMap) == GIF_ERROR) {
			QuitGifError(GifFileIn, GifFileOut);
		}
	}

	/* Scan the content of the GIF file and load the image(s) in: */
	do {
		if (DGifGetRecordType(GifFileIn, &RecordType) == GIF_ERROR) {
			QuitGifError(GifFileIn, GifFileOut);
		}

		switch (RecordType) {
		case IMAGE_DESC_RECORD_TYPE:
			if (DGifGetImageDesc(GifFileIn) == GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}
			if ((++ImageNum == ImageN) && ImageNFlag) {
				/* We are suppose to modify this image color
				 * map, do it: */
				GifFileIn->SColorMap =
				    ModifyColorMap(GifFileIn->SColorMap);
				if (!HasGIFOutput) {
					/* We can quit here, as we have the
					 * color map: */
					DGifCloseFile(GifFileIn, NULL);
					fclose(ColorFile);
					exit(EXIT_SUCCESS);
				}
			}
			if (HasGIFOutput) {
				if (EGifPutImageDesc(
				        GifFileOut, GifFileIn->Image.Left,
				        GifFileIn->Image.Top,
				        GifFileIn->Image.Width,
				        GifFileIn->Image.Height,
				        GifFileIn->Image.Interlace,
				        GifFileIn->Image.ColorMap) ==
				    GIF_ERROR) {
					QuitGifError(GifFileIn, GifFileOut);
				}
			}

			if (!TranslateFlag ||
			    (ImageNFlag && (ImageN != ImageNum))) {
				/* Now read image itself in decoded form as we
				 * don't */
				/* really care what we have there, and this is
				 * much  */
				/* faster.
				 */
				if (DGifGetCode(GifFileIn, &CodeSize,
				                &CodeBlock) == GIF_ERROR) {
					QuitGifError(GifFileIn, GifFileOut);
				}
				if (HasGIFOutput) {
					if (EGifPutCode(GifFileOut, CodeSize,
					                CodeBlock) ==
					    GIF_ERROR) {
						QuitGifError(GifFileIn,
						             GifFileOut);
					}
				}
				while (CodeBlock != NULL) {
					if (DGifGetCodeNext(GifFileIn,
					                    &CodeBlock) ==
					    GIF_ERROR) {
						QuitGifError(GifFileIn,
						             GifFileOut);
					}
					if (HasGIFOutput) {
						if (EGifPutCodeNext(
						        GifFileOut,
						        CodeBlock) ==
						    GIF_ERROR) {
							QuitGifError(
							    GifFileIn,
							    GifFileOut);
						}
					}
				}
			} else /* we need to mung pixels intices */
			{
				int i;
				register GifPixelType *cp;

				GifPixelType *Line = (GifPixelType *)malloc(
				    GifFileIn->Image.Width *
				    sizeof(GifPixelType));
				for (i = 0; i < GifFileIn->Image.Height; i++) {
					if (DGifGetLine(
					        GifFileIn, Line,
					        GifFileIn->Image.Width) ==
					    GIF_ERROR) {
						QuitGifError(GifFileIn,
						             GifFileOut);
					}

					/* translation step goes here */
					for (cp = Line;
					     cp < Line + GifFileIn->Image.Width;
					     cp++) {
						*cp = Translation[*cp];
					}

					if (EGifPutLine(
					        GifFileOut, Line,
					        GifFileIn->Image.Width) ==
					    GIF_ERROR) {
						QuitGifError(GifFileIn,
						             GifFileOut);
					}
				}
				free((char *)Line);
			}
			break;
		case EXTENSION_RECORD_TYPE:
			assert(GifFileOut != NULL); /* might pacify Coverity */
			/* pass through extension records */
			if (DGifGetExtension(GifFileIn, &ExtCode, &Extension) ==
			    GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}
			if (Extension == NULL) {
				break;
			}
			if (EGifPutExtensionLeader(GifFileOut, ExtCode) ==
			    GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}
			if (EGifPutExtensionBlock(GifFileOut, Extension[0],
			                          Extension + 1) == GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}
			while (Extension != NULL) {
				if (DGifGetExtensionNext(
				        GifFileIn, &Extension) == GIF_ERROR) {
					QuitGifError(GifFileIn, GifFileOut);
				}
				if (Extension != NULL) {
					if (EGifPutExtensionBlock(
					        GifFileOut, Extension[0],
					        Extension + 1) == GIF_ERROR) {
						QuitGifError(GifFileIn,
						             GifFileOut);
					}
				}
			}
			if (EGifPutExtensionTrailer(GifFileOut) == GIF_ERROR) {
				QuitGifError(GifFileIn, GifFileOut);
			}
			break;
		case TERMINATE_RECORD_TYPE:
			break;
		default: /* Should be trapped by DGifGetRecordType. */
			break;
		}
	} while (RecordType != TERMINATE_RECORD_TYPE);

	if (DGifCloseFile(GifFileIn, &ErrorCode) == GIF_ERROR) {
		PrintGifError(ErrorCode);
		exit(EXIT_FAILURE);
	}
	if (HasGIFOutput) {
		if (EGifCloseFile(GifFileOut, &ErrorCode) == GIF_ERROR) {
			PrintGifError(ErrorCode);
			exit(EXIT_FAILURE);
		}
	}

	return 0;
}

/******************************************************************************
 Modify the given colormap according to global variables setting.
******************************************************************************/
static ColorMapObject *ModifyColorMap(ColorMapObject *ColorMap) {
	int i, Dummy, Red, Green, Blue;

	if (SaveFlag) {
		/* Save this color map to ColorFile: */
		for (i = 0; i < ColorMap->ColorCount; i++) {
			fprintf(ColorFile, "%3d %3d %3d %3d\n", i,
			        ColorMap->Colors[i].Red,
			        ColorMap->Colors[i].Green,
			        ColorMap->Colors[i].Blue);
		}
		return (ColorMap);
	} else if (LoadFlag) {
		/* Read the color map in ColorFile into this color map: */
		for (i = 0; i < ColorMap->ColorCount; i++) {
			if (feof(ColorFile)) {
				GIF_EXIT("Color file to load color map from, "
				         "too small.");
			}
			if (fscanf(ColorFile, "%3d %3d %3d %3d\n", &Dummy, &Red,
			           &Green, &Blue) == 4) {
				ColorMap->Colors[i].Red = Red;
				ColorMap->Colors[i].Green = Green;
				ColorMap->Colors[i].Blue = Blue;
			}
		}
		return (ColorMap);
	} else if (GammaFlag) {
		/* Apply gamma correction to this color map: */
		double Gamma1 = 1.0 / Gamma;
		for (i = 0; i < ColorMap->ColorCount; i++) {
			ColorMap->Colors[i].Red =
			    ((int)(255 * pow(ColorMap->Colors[i].Red / 255.0,
			                     Gamma1)));
			ColorMap->Colors[i].Green =
			    ((int)(255 * pow(ColorMap->Colors[i].Green / 255.0,
			                     Gamma1)));
			ColorMap->Colors[i].Blue =
			    ((int)(255 * pow(ColorMap->Colors[i].Blue / 255.0,
			                     Gamma1)));
		}
		return (ColorMap);
	} else if (TranslateFlag) {
		ColorMapObject *NewMap;
		int Max = 0;

		/* Read the translation table in TranslateFile: */
		for (i = 0; i < ColorMap->ColorCount; i++) {
			int tmp;
			if (feof(TranslateFile)) {
				GIF_EXIT("Color file to load color map from, "
				         "too small.");
			}
			if (fscanf(TranslateFile, "%3d %3d\n", &Dummy, &tmp) ==
			    2) {
				Translation[i] = tmp & 0xff;
				if (Translation[i] > Max) {
					Max = Translation[i];
				}
			}
		}

		if ((NewMap = GifMakeMapObject(1 << GifBitSize(Max + 1),
		                               NULL)) == NULL) {
			GIF_EXIT("Out of memory while allocating color map!");
		}

		/* Apply the translation; we'll do it to the pixels, too */
		for (i = 0; i < ColorMap->ColorCount; i++) {
			NewMap->Colors[i] = ColorMap->Colors[Translation[i]];
		}

		return (NewMap);
	} else {
		GIF_EXIT("Nothing to do!");
		return (ColorMap);
	}
}

/******************************************************************************
 Close both input and output file (if open), and exit.
******************************************************************************/
static void QuitGifError(GifFileType *GifFileIn, GifFileType *GifFileOut) {
	if (GifFileIn != NULL) {
		PrintGifError(GifFileIn->Error);
		EGifCloseFile(GifFileIn, NULL);
	}
	if (GifFileOut != NULL) {
		PrintGifError(GifFileOut->Error);
		EGifCloseFile(GifFileOut, NULL);
	}
	exit(EXIT_FAILURE);
}

/* end */