#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/fcntl.h>
#include <string.h>
#include <strings.h>
#include "buffer.h"
#include "mmap.h"
#include "uint32.h"
#include "mstorage.h"

mstorage_t idx;
char* map;

int compar(const void* a,const void* b) {
  int i;
  if ((i=strcmp(map+*(uint32*)a,map+*(uint32*)b)))
    return i;
  else
    return *(uint32*)b-*(uint32*)a;
}

int compari(const void* a,const void* b) {
  int i;
  if ((i=strcasecmp(map+*(uint32*)a,map+*(uint32*)b)))
    return i;
  else
    return *(uint32*)b-*(uint32*)a;
}

int main(int argc,char* argv[]) {
  long filelen;
  char* filename=argv[1];
  uint32 magic,attribute_count,record_count,indices_offset,size_of_string_table;
  uint32 wanted,casesensitive,dn,objectClass;
  int ignorecase,fastindex;

  ignorecase=fastindex=0;

  mstorage_init(&idx);

  if (argc<3) {
    buffer_putsflush(buffer_2,"usage: ./addindex filename attribute [i][f]\n"
		     "if i is present, make index case insensitive.\n"
		     "if f is present, make index twice as large, but quicker.\n");
    return 1;
  }

  if (argc>3) {
    if (strchr(argv[3],'i')) ignorecase=1;
    if (strchr(argv[3],'f')) fastindex=1;
  }
  map=mmap_read(filename,&filelen);
  uint32_unpack(map,&magic);
  if (magic!=0xfefe1da9) {
    buffer_putsflush(buffer_2,"file format not recognized!  Invalid magic!\n");
    return 1;
  }
  uint32_unpack(map+4,&attribute_count);
  uint32_unpack(map+2*4,&record_count);
  uint32_unpack(map+3*4,&indices_offset);
  uint32_unpack(map+4*4,&size_of_string_table);

  {
    unsigned int i;
    char* x=map+5*4+size_of_string_table;
    wanted=casesensitive=dn=objectClass=0;
    for (i=0; i<attribute_count; ++i) {
      uint32 j;
      uint32_unpack(x,&j);
//      buffer_puts(buffer_1,map+j); buffer_putsflush(buffer_1,"\n");
      if (!strcasecmp(map+j,"dn")) dn=j;
      if (!strcasecmp(map+j,"objectClass")) objectClass=j;
      if (!strcasecmp(map+j,argv[2])) {
//	buffer_putsflush(buffer_2,"found attribute!\n");
	wanted=j; casesensitive=x+attribute_count*4-map;
	uint32_unpack(map+casesensitive,&j);
	if (j) {
	  buffer_putsflush(buffer_2,"case sensitivity flag is nonzero?!\n");
	  return 1;
	}
      }
      x+=4;
    }
    if (!wanted) {
      buffer_putsflush(buffer_2,"that attribute is not in the database!\n");
      return 1;
    }
    if (!dn || !objectClass) {
      buffer_putsflush(buffer_2,"dn or objectClass not found!\n");
      return 1;
    }
  }

  {
    uint32 i,counted=0;
    char* x=map+5*4+size_of_string_table+attribute_count*8;
    for (i=0; i<record_count; ++i) {
      uint32 j,k;
      uint32_unpack(x,&j);
      if (wanted==dn) {
	uint32_unpack(x+8,&k);
	mstorage_add(&idx,(char*)&k,4);
	if (fastindex)
	  mstorage_add(&idx,(char*)&i,4);
	++counted;
	x+=j*8;
      } else if (wanted==objectClass) {
	uint32_unpack(x+12,&k);
	mstorage_add(&idx,(char*)&k,4);
	if (fastindex)
	  mstorage_add(&idx,(char*)&i,4);
	++counted;
	x+=j*8;
      } else {
	x+=16;
	for (; j>2; --j) {
	  uint32_unpack(x,&k);
	  if (k==wanted) {
	    uint32_unpack(x+4,&k);
	    mstorage_add(&idx,(char*)&k,4);
	    if (fastindex)
	      mstorage_add(&idx,(char*)&i,4);
	    ++counted;
	  }
	  x+=8;
	}
      }
    }
    buffer_putulong(buffer_1,counted);
    buffer_putsflush(buffer_1," entries to be sorted...");
    if (ignorecase)
      qsort(idx.root,counted,4*(fastindex+1),compari);
    else
      qsort(idx.root,counted,4*(fastindex+1),compar);
    buffer_putsflush(buffer_1," done.\n");
    munmap(map,filelen);
    {
      int fd=open(filename,O_RDWR);
      if (fd<0) {
	buffer_putsflush(buffer_2,"could not re-open database file read-write\n");
	exit(1);
      }
      ftruncate(fd,filelen+3*4+counted*4*(fastindex+1));
      map=mmap(0,filelen+(counted+3)*4*(fastindex+1),PROT_WRITE,MAP_SHARED,fd,0);
      if (map==(char*)-1) {
	buffer_putsflush(buffer_2,"could not mmap database file read-write\n");
	exit(1);
      }
      uint32_pack(map+casesensitive,ignorecase);
      uint32_pack(map+filelen,fastindex);
      uint32_pack(map+filelen+4,filelen+3*4+counted*4*(fastindex+1));
      uint32_pack(map+filelen+8,wanted);
      {
	char* x=map+filelen+12;
	unsigned long i;
	for (i=0; i<counted; ++i) {
	  uint32_pack(x,((uint32*)idx.root)[i<<fastindex]);
	  x+=4;
	}
	if (fastindex) {
	  /* index type 1 also saves the record number for each table
	   * entry.  Since normal searches will bsearch over the offsets
	   * and only then ask for the record number, we try to be cache
	   * friendly and save one table with the offsets and one table
	   * with the record numbers, instead of one table with tuples. */
	  for (i=0; i<counted; ++i) {
	    uint32_pack(x,((uint32*)idx.root)[i*2+1]);
	    x+=4;
	  }
	}
      }
    }
  }
  return 0;
}