/*
 * Dominic Jonak (dom@cmu.edu)
 * Autogen v1.8 (06/16/2010)
 *
 * Description: Website creation program, merges a content (source.txt)
 *              and layout (layout.html) file.  Assumes very strict
 *              structure for both.
 * 
 *   Feel free to use the code, just don't remove this comment.
 *
 * Disclaimer:  It's not finished so don't complain if it's not
 *              perfect.  Don't expect any support either.
 */

#define _GNU_SOURCE
#include <string.h>

#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>



const int stripComments=1;/* whether comments should be stripped out or kept */

int numSections=0;
char **sectionNames=NULL;
char **sectionTexts=NULL;
void addSectionName(const char *s){
    numSections++;
    sectionNames = (char **)realloc(sectionNames, 
				    numSections * sizeof(char *));
    sectionNames[numSections-1] = strdup(s);
}

int numCategories=0;
char **categoryNames=NULL;
char **capCategoryNames=NULL;
void addCategoryName(const char *s){
    numCategories++;
    categoryNames = (char **)realloc(categoryNames, 
				     numCategories * sizeof(char *));
    categoryNames[numCategories-1] = strdup(s);
}

void makeCapCategoryNames(){
    int i;
    capCategoryNames = (char **)malloc(numCategories * sizeof(char *));
    for(i=0;i<numCategories;i++){
	capCategoryNames[i] = strdup(categoryNames[i]);
	capCategoryNames[i][0] = toupper(capCategoryNames[i][0]);
    }
}

int getSectionIndex(const char *s){
    int i;
    for(i=0;i<numSections;i++)
	if(!strcasecmp(s, sectionNames[i]))
	    return i;
    return -1;
}

void readLayoutHeader(FILE *f){
    char buf[256];
    int i;
    if(1 != fscanf(f, "%s", buf) || strcmp("<!--", buf)){
	fprintf(stderr, "Error, bad layout header format\n");
	exit(-1);
    }

    while(1){
	if(1 != fscanf(f, "%s", buf)){
	    fprintf(stderr, "Error, bad layout header format\n");
	    exit(-1);
	}
	if(!strcmp("-->", buf))break;
	addSectionName(buf);
    }

    /* if the first section is the count, remove it */
    if(numSections>1 && numSections-1 == atoi(sectionNames[0])){
	sectionNames = sectionNames+1;
	numSections--;
    }

    printf("Read %d sections:\n", numSections);
    for(i=0;i<numSections;i++)
	printf("%d: %s\n", i, sectionNames[i]);
}

char *myconcat(char *oldText, const char *addedText){
    int oldlen = 0;
    int addedlen = 0;
    char *ret = NULL;

    if(oldText)
      oldlen = strlen(oldText);

    /* clip white space from the beginning and end of addedText */
    while(isspace(*addedText))addedText++;
    addedlen = strlen(addedText);
    while(addedlen>0 && isspace(addedText[addedlen-1]))addedlen--;

    ret = (char *)realloc(oldText, oldlen + addedlen + 2);
    /* add a newline between concats */
    /*if(oldlen)ret[oldlen++]='\n';*/
    memcpy(ret+oldlen, addedText, addedlen);
    ret[oldlen+addedlen]='\0';
    return ret;
}

char *readLayoutSection(FILE *f){
    char buf[1024];
    char commentBuf[sizeof(buf)];
    char *ret=NULL;
    while(1){
	if(!fgets(buf, sizeof(buf), f)){
	    if(feof(f))break;
	    fprintf(stderr, "Error reading layout section\n");
	    exit(-1);
	}

	/* check if this line is a comment */
	if(1 == sscanf(buf, "<!-- %s -->", commentBuf)){
	  /* check if this comment signals the end of the current section */
	  if(-1 != getSectionIndex(commentBuf))break;
	  /* this is an internal comment, optionally strip it out */
	  if(stripComments)continue;
	}

	ret = myconcat(ret, buf);
    }
    return ret;
}

void readLayoutSections(FILE *f){
    int i;
    sectionTexts = (char **)malloc((numSections+1) * sizeof(char *));

    for(i=0;i<numSections+1;i++){
	/*printf("Reading layout section %d of %d\n", i, numSections);*/
	sectionTexts[i] = readLayoutSection(f);
	/*printf("Here it is:\n%s\n", sectionTexts[i]);*/
    }
}

void readLayout(const char *file){
    FILE *f = fopen(file, "r");
    if(!f){
	fprintf(stderr, "Error, unable to open layout file \"%s\"\n", file);
	exit(-1);
    }

    readLayoutHeader(f);
    readLayoutSections(f);
    fclose(f);
}

char *currentHTML=NULL;
void readSourceHeader(FILE *f){
    char buf[256];
    int i;
    if(1 != fscanf(f, "%s", buf) || strcmp("categories:", buf)){
	fprintf(stderr, "Error, bad source header format\n");
	exit(-1);
    }

    while(1){
	if(1 != fscanf(f, "%s", buf)){
	    fprintf(stderr, "Error, bad source header format\n");
	    exit(-1);
	}
	if(strstr(buf, ".htm"))break;
	addCategoryName(buf);
    }

    currentHTML = strdup(buf);

    /* if the first category is the count, remove it */
    if(numCategories>1 && numCategories-1 == atoi(categoryNames[0])){
	categoryNames = categoryNames+1;
	numCategories--;
    }

    makeCapCategoryNames();
    printf("Read %d categories:\n", numCategories);
    for(i=0;i<numCategories;i++)
	printf("%d: %s (%s)\n", i, categoryNames[i], capCategoryNames[i]);
}

/* helper function for writeTitle creates the gradient*/
int sColor[3] = {0x66, 0x66, 0x99};
int eColor[3] = {0x00, 0x00, 0x66};
int numColorSteps=10;

void buildFont(FILE *f, int i, char c){
  int j;
  if(i<=0)i = 0;
  else if(i>=numColorSteps) i = numColorSteps;
  fprintf(f, "<font color=\'#");
  for(j=0;j<3;j++)
    fprintf(f, "%02x", sColor[j] + i*(eColor[j] - sColor[j])/numColorSteps);
  fprintf(f, "\'>%c</font>", c);
}

void writeTitle(FILE *f, const char *title){
    /* put this in to get a gradient effect */
#if 0
    int len = strlen(title);
    int k;

    for(k=0;k<len/2 + 1;k++)
	buildFont(f, k, title[k]);
    for(k=(len-1)/2;k>0;k--)
	buildFont(f, k, title[len-k]);
    fprintf(f, "\n");
#else
    fprintf(f, "%s\n", title);
#endif

    printf("%s\n", title);
}
void writeCategories(FILE *f){
    int i;
    char linkHTML[256];
    for(i=0;i<numCategories;i++){
      sprintf(linkHTML, "%s.html", categoryNames[i]);
      fprintf(f, "<p><a href=\"%s\" style=\'text-decoration:none", linkHTML);
      /* highlight the current file */
      if(!strcasecmp(currentHTML, linkHTML))
	fprintf(f, ";color:#9999cc");
      fprintf(f, "\'>%s</a></p>\n", capCategoryNames[i]);
    }
}
void writeLink(FILE *f, char *link){
    char linkname[256], linkURL[256];
    if(2 != sscanf(link, "%s %s", linkURL, linkname)){
	fprintf(stderr, "Error creating link from \"%s\"\n", link);
	exit(-1);
    }
    /* support for multi-word link texts */
    strcpy(linkname, strstr(link+strlen(linkURL), linkname));
    fprintf(f, "<li><a href=\"%s\">%s</a>\n", linkURL, linkname);
}

char *extractSectionName(char *data, char **rest){
  int i=0;
  *rest = NULL;
  if(!data || '&' != data[0])return NULL;
  data++;/* skip the '&' */
  while(1){
    /* advance to the end of the first token */
    if( (data[i]) && !isspace(data[i]) ){
      i++;
      continue;
    }

    /* make sure it ends with a ';' */
    if(';' != data[i-1])return NULL;

    /* pull out and data after the token and save it in rest */
    *rest = &data[i];
    while( **rest && isspace(**rest) )(*rest)++;
    while(**rest && isspace((*rest)[strlen(*rest)-1]))(*rest)[strlen(*rest)-1]='\0';
    data[i-1] = '\0';

    /* make sure it's a valid section */
    if(strcasecmp("end", data) && -1 == getSectionIndex(data)){
      data[i-1] = ';';
      return NULL;
    }

    break;
  }

  return data;
}

void readPageSource(FILE *f){
    char linebuf[1024];
    char *sectionbuf;
    char *restOfLine=NULL;
    FILE *output=NULL;
    char lastSection[sizeof(linebuf)];
    int firstLineInSection=1;
    lastSection[0]='\0';

    if(!currentHTML){
	fprintf(stderr, "Have no html file to write too...\n");
	exit(-1);
    }

    output = fopen(currentHTML, "w");
    if(!output){
	fprintf(stderr, "Unable to write to \"%s\"\n", currentHTML);
	exit(-1);
    }

    printf("%20s: ", currentHTML);

    while(1){ /* read each line */
	if(!fgets(linebuf, sizeof(linebuf), f)){
	    fprintf(stderr, "Error bad source for %s\n", currentHTML);
	    exit(-1);
	}
	/*
	if(strlen(linebuf)== sizeof(linebuf)-1){
	    fprintf(stderr, "Buffer too small for %s\n", currentHTML);
	    exit(-1);
	}
	*/

	if(linebuf[strlen(linebuf)-1] == '\n')
	    linebuf[strlen(linebuf)-1] = '\0';

	if((sectionbuf = extractSectionName(linebuf, &restOfLine))){
	  /*fprintf(output, "<!-- Dealing with section %s -->\n", sectionbuf);*/
	  firstLineInSection=1;
	    if(!strcasecmp("end", sectionbuf)){
		/* reached end */
		/*printf("%s: Reached end\n", currentHTML);*/
		fprintf(output, "%s\n", sectionTexts[numSections]);
		break;

	    }else{
		if(!strcasecmp(sectionbuf, "right"))
		    writeCategories(output);
		else if(!strcasecmp(sectionbuf, "bottom") &&
			strcasecmp(lastSection, "right")){
		    /*fprintf(output, "<!-- Inserting %s -->\n", "right");*/
		    fprintf(output, "%s\n", sectionTexts[getSectionIndex("right")]);
		    writeCategories(output);
		}

		/* insert the specified section */
		/*printf("%s: Inserting section %s\n", currentHTML, sectionbuf);*/
		/*fprintf(output, "<!-- Inserting %s -->\n", sectionbuf);*/
		fprintf(output, "%s", sectionTexts[getSectionIndex(sectionbuf)]);
		if(restOfLine)
		  fprintf(output, "%s", restOfLine);
		strcpy(lastSection, sectionbuf);
	    }

	}else{
	    /* not a comment, write this */
	    /*printf("%s/%s: Writing source \"%s\"\n", currentHTML, lastSection, linebuf);*/
	    if(!strcasecmp(lastSection, "bottom"))
		writeLink(output, linebuf);
	    else if(!strcasecmp(lastSection, "top"))
		writeTitle(output, linebuf);
	    else{
	      /* remove leading whitespace */
	      char *s = linebuf;
	      while(*s && isspace(*s))s++;

	      /* add a newline if appropriate */
	      if(firstLineInSection)
		firstLineInSection=0;
	      else 
		fprintf(output, "\n");

	      fprintf(output, "%s", s);
	    }
	}
    } /* done reading each line of the source of this page */

    fclose(output);
    free(currentHTML);
    currentHTML=NULL;

    /* determine next file */
    if(1 == fscanf(f, "%s", linebuf)){
	if(!strstr(linebuf, ".htm")){
	    fprintf(stderr, "Error, writing to strange file \"%s\"\n", linebuf);
	    exit(-1);
	}
	currentHTML = strdup(linebuf);
    }
}

void processSource(const char *file){
    FILE *f = fopen(file, "r");
    if(!f){
	fprintf(stderr, "Error, unable to open source file \"%s\"\n", file);
	exit(-1);
    }

    readSourceHeader(f);
    while(!feof(f))
	readPageSource(f);
    fclose(f);
}

int main(){
  readLayout("layout.html");
  processSource("source.txt");
  return 0;
}