#include <dirent.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>

/*
Copyright (c) 2021 Derek Stevens
Copyright (c) 2021 Devine Lu Linvega

Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE.
*/

/* clang-format off */

#define NAME "nilFM"
#define DOMAIN "https://nilfm.cc"
#define ABOUT "Derek Stevens &lt;"\
              "<a href='mailto://drkste@zoho.com'>drkste@zoho.com</a>&gt;<br/>"\
              "artist, programmer, philosopher<br/><br/>"\
              "verify my signature: <a href='/serv/signingKey.pub'>signing public key</a><br/>"\
              "send me an encrypted message: <a href='/serv/encryptionKey.pub'>encrypted public key</a>"
#define SITEROOT "../www/"
#define MAINCSS "/new.css"
#define FRONTCSS "/front.css"
#define LICENSE ""
#define SOURCE ""

/* clang-format on */

struct dirent* dir;

typedef struct Lexicon {
  int len, refs[512];
  char files[512][64];
} Lexicon;

/* clang-format off */

char  clca(char c) { return c >= 'A' && c <= 'Z' ? c + ('a' - 'A') : c; } /* char to lowercase */
char  cuca(char c) { return c >= 'a' && c <= 'z' ? c - ('a' - 'A') : c; } /* char to uppercase */
int   slen(char *s) { int i = 0; while(s[i] && s[++i]) { ; } return i; } /* string length */
char *st__(char *s, char (*fn)(char)) { int i = 0; char c; while((c = s[i])) s[i++] = fn(c); return s; }
char *stuc(char *s) { return st__(s, cuca); } /* string to uppercase */
char *stlc(char *s) { return st__(s, clca); } /* string to lowercase */
char *scpy(char *src, char *dst, int len) { int i = 0; while((dst[i] = src[i]) && i < len - 2) i++; dst[i + 1] = '\0'; return dst; } /* string copy */
int   scmp(char *a, char *b) { int i = 0; while(a[i] == b[i]) if(!a[i++]) return 1; return 0; } /* string compare */
char *scsw(char *s, char a, char b) { int i = 0; char c; while((c = s[i])) s[i++] = c == a ? b : c; return s; } /* string char swap */
char *scat(char *dst, const char *src) { char *ptr = dst + slen(dst); while(*src) *ptr++ = *src++; *ptr = '\0'; return dst; } /* string cat */
int   ssin(char *s, char *ss) { int a = 0, b = 0; while(s[a]) { if(s[a] == ss[b]) { if(!ss[b + 1]) return a - b; b++; } else b = 0; a++; } return -1; } /* string substring index */
char *ccat(char *dst, char c) { int len = slen(dst); dst[len] = c; dst[len + 1] = '\0'; return dst; }

/* clang-format on */

int fpinject(FILE* f, Lexicon* l, char* filepath);

int error(char* msg, char* val) {
  printf("Error: %s(%s)\n", msg, val);
  return 0;
}

int ismetanav(char* name) { return scmp(name, "meta.nav"); }

int findf(Lexicon* l, char* f) {
  int i;
  char filename[64];
  scat(scsw(stlc(scpy(f, filename, 64)), ' ', '_'), ".htm");
  for (i = 0; i < l->len; ++i)
    if (scmp(l->files[i], filename))
      return i;
  return -1;
}

void fpedited(FILE* f, char* path) {
  struct stat attr;
  stat(path, &attr);
  fputs("<span style='float:right'>", f);
  fprintf(f, "Edited on %s ", ctime(&attr.st_mtime));
  fputs("</span>", f);
}

int fpportal(FILE* f, Lexicon* l, char* s, int head) {
  int target;
  char srcpath[64], filename[64];
  target = findf(l, s);
  if (target < 0)
    return error("Missing portal", s);
  srcpath[0] = 0;
  filename[0] = 0;
  scat(scat(scat(srcpath, "inc/"), scpy(s, filename, 64)), ".htm");
  if (head)
    fprintf(
      f,
      "<h2 id='%s'><a href='%s.html'>%s</a></h2>",
      scsw(filename, ' ', '_'),
      filename,
      s);
  fpinject(f, l, srcpath);
  l->refs[target]++;
  return 1;
}

int fptemplate(FILE* f, Lexicon* l, char* s) {
  int target;
  if (s[0] == '/')
    return fpportal(f, l, s + 1, 1);
  target = findf(l, s);
  if (target < 0)
    return error("Missing link", s);
  fprintf(f, "<a href='%s.html' class='local'>", scsw(stlc(s), ' ', '_'));
  fprintf(f, "%s</a>", scsw(stlc(s), '_', ' '));
  l->refs[target]++;
  return 1;
}

int fpinject(FILE* f, Lexicon* l, char* filepath) {
  FILE* inc;
  char c, s[1024];
  unsigned char t = 0;
  scsw(filepath, ' ', '_');
  if (!(inc = fopen(filepath, "r")))
    return error("Missing include", filepath);
  s[0] = 0;
  while ((c = fgetc(inc)) != EOF) {
    if (c == '}') {
      t = 0;
      if (!fptemplate(f, l, s))
        return 0;
      continue;
    }
    if (c == '{') {
      s[0] = 0;
      t = 1;
      continue;
    }
    if (slen(s) > 1023)
      return error("Templating error", filepath);
    if (t)
      ccat(s, c);
    else
      fprintf(f, "%c", c);
  }
  fclose(inc);
  return 1;
}

FILE* build(FILE* f, Lexicon* l, char* name, char* srcpath) {
  if (!f)
    return f;
  /* begin */
  fputs("<!DOCTYPE html><html lang='en'>", f);
  fputs("<head>", f);
  fprintf(
    f,
    "<meta charset='utf-8'>"
    "<meta name='description' content='%s'/>"
    "<meta name='viewport' content='width=device-width,initial-scale=1'>",
    "lair of drkste aka nilix: programmer, artist, philosopher");
  if (ismetanav(name)) {
    fputs("<link rel='stylesheet' type='text/css' href='" FRONTCSS "'>", f);
  } else {
    fputs("<link rel='stylesheet' type='text/css' href='" MAINCSS "'>", f);
  }
  fprintf(
    f,
    "<link rel='shortcut icon' href='/favicon.ico'>"
    "<title>" NAME " &mdash; %s</title>",
    name);
  fputs("</head>", f);
  fputs("<body>", f);
  /* header */
  fputs("<header>", f);
  if (ismetanav(name)) {
    fputs("<h1>nilFM</h1>", f);
  } else {
    fputs("<h1><a href='/'>nilFM</a></h1>", f);
  }

  fputs("</header>", f);
  /* about (main page only) */
  if (ismetanav(name)) {
    fputs("<div id='about'>" ABOUT "</div>", f);
  }
  /* nav */
  fputs("<nav>", f);
  if (!fpportal(f, l, "meta.nav", 0))
    printf(">>> Building failed: %s\n", name);
  fputs("</nav>", f);
  /* main */
  if (!ismetanav(name)) {
    fputs("<main>\n\n", f);
    fputs("<!-- Generated file, do not edit -->\n\n", f);
    fprintf(f, "<h2>%s</h2>", name);
    if (!fpinject(f, l, srcpath))
      printf(">>> Building failed: %s\n", name);
    fputs("\n\n</main>", f);
    /* footer */
    fputs("<footer>", f);
    fpedited(f, srcpath);
    fputs(
      "contact: <a href='mailto://drkste@zoho.com'>drkste@zoho.com</a> ",
      f);
    fputs("(<a href='keys.html'>keys</a>)", f);
    /* fputs("<a href='" LICENSE "' target='_blank'>BY-NC-SA 4.0</a>", f) */;
    fputs("</footer>", f);
  }
  /* end */
  fputs("</body></html>", f);
  return f;
}

int generate(Lexicon* l) {
  int i = 0;
  char srcpath[64], dstpath[64], filename[64];
  for (i = 0; i < l->len; ++i) {
    srcpath[0] = 0;
    dstpath[0] = 0;
    filename[0] = 0;
    /* src */
    scpy(l->files[i], filename, ssin(l->files[i], ".htm") + 1);
    scat(srcpath, "inc/");
    scat(srcpath, filename);
    scat(srcpath, ".htm");
    /* dst */
    if (scmp(filename, "meta.nav")) {
      scat(dstpath, SITEROOT);
      scat(dstpath, "index.html");
    } else {
      scat(dstpath, SITEROOT);
      scat(dstpath, filename);
      scat(dstpath, ".html");
    }
    fclose(build(fopen(dstpath, "w"), l, scsw(filename, '_', ' '), srcpath));
  }
  printf("Generated %d files\n", i);
  return 1;
}

int index(Lexicon* l, DIR* d) {
  while ((dir = readdir(d)))
    if (ssin(dir->d_name, ".htm") > 0) {
      l->refs[l->len] = 0;
      scpy(dir->d_name, l->files[l->len++], 64);
    }
  closedir(d);
  printf("Indexed %d terms\n", l->len);
  return 1;
}

void inspect(Lexicon* l) {
  int i;
  for (i = 0; i < l->len; ++i)
    if (!l->refs[i])
      error("Orphaned", l->files[i]);
}

int main(void) {
  Lexicon lex;
  DIR* d;
  lex.len = 0;
  if (!(d = opendir("inc")))
    return error("Open", "Missing inc/ folder. ");
  if (!index(&lex, d))
    return error("Indexing", "Failed");
  if (!generate(&lex))
    return error("Generating", "Failed");
  inspect(&lex);
  return 0;
}