#include <stdlib.h>
#include <stdint.h>
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>

#include "mystdlib.h"

enum { g_outfiles = 17 };

static struct {
  int      outfiles[g_outfiles];
  uint8_t *outbuf  [g_outfiles];
  size_t   outfill [g_outfiles];
} g_state;

static int g_northern_version;;
static uint8_t cp437_to_iso8859_1_table[] = {
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
  0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
  0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
  0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
  0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
  0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
  0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
  0xc7, 0xfc, 0xe9, 0xe2, 0xe4, 0xe0, 0xe5, 0xe7, 0xea, 0xeb, 0xe8, 0xef, 0xee, 0xec, 0xc4, 0xc5,
  0xc9, 0xe6, 0xc6, 0xf4, 0xf6, 0xf2, 0xfb, 0xf9, 0xff, 0xd6, 0xdc, 0xa2, 0xa3, 0xa5, 0x2e, 0x2e,
  0xe1, 0xed, 0xf3, 0xfa, 0xf1, 0xd1, 0xaa, 0xba, 0xbf, 0x2e, 0xac, 0xbd, 0xbc, 0xa1, 0xab, 0xbb,
  0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e,
  0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e,
  0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e,
  0x2e, 0xdf, 0x2e, 0x2e, 0x2e, 0x2e, 0xb5, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e, 0x2e,
  0x2e, 0xb1, 0x2e, 0x2e, 0x2e, 0x2e, 0xf7, 0x2e, 0xb0, 0x2e, 0xb7, 0x2e, 0x2e, 0xb2, 0x2e, 0xa0
};

static void dump_string( uint8_t *start, size_t len, int file ) {
  uint8_t *dest = g_state.outbuf[file] + g_state.outfill[file];
  g_state.outfill[file] += len;
  while( len-- )
    *(dest++) = cp437_to_iso8859_1_table[ *(start++) ];
}

static void dump_field( uint8_t **end, int file ) {
  uint8_t len = (*end)[-1];
  *end -= len + 1;
  dump_string( *end, len, file);
}

static void finish_record( ) {
  int i;
  for( i=0; i<g_outfiles; ++i )
    *( g_state.outbuf[i] + g_state.outfill[i]++ ) = '\n';
}

static uint16_t load_word( uint8_t *table_start, uint16_t base, int offset ) {
  int dword_offset = offset >> 1;

  /* If a word(subflag, t_off) would span over the end of a 0x4000
     byte page, it is placed on the next page. All other words are
     shifted backwards, as well. */
  table_start += 4;
  if( base + 4 + 4 * dword_offset > 0x1ffc )
    table_start += 3 & ( 4 - ( base & 3 ) );

  return ((uint16_t*)table_start)[offset];
}

static void dump_primary( uint8_t *end, uint32_t flags ) {
  /* First dump type of record (should be 1) */
  dump_string( end, 1, 0 );

  /* Dump first 5 chars of zip, they're always there */
  dump_string( end -= 5, 5, 1 );

  /* Dump first 5 chars of prefix, they're always here in s and w */
  if( !g_northern_version )
    dump_string( end -= 5, 5, 2 );

  /* There is another version of the zip code present, if this bit is set */
  if( flags & 0x0080 ) dump_string( end -= 5, 5, 3 );

  /* There is an unclear X present, if this bit is set */
  if( flags & 0x0040 ) dump_string( end -= 1, 1, 4 );

  /* There is another version of the prefix present, if this bit is set */
  if( flags & 0x0020 ) {
    if( !g_northern_version )
      dump_string( end -= 5, 5, 5 );
    else
      dump_field( &end, 5 );
  }

  if( flags & 0x0010 ) dump_field( &end, 6 );
  if( flags & 0x0008 ) dump_field( &end, 7 );
  if( flags & 0x0004 ) dump_field( &end, 8 );
  if( flags & 0x0002 ) dump_field( &end, 9 );
  if( flags & 0x0001 ) dump_field( &end, 10 );
  if( flags & 0x8000 ) dump_field( &end, 11 );
  if( flags & 0x4000 ) dump_field( &end, 12 );
  if( flags & 0x2000 ) dump_field( &end, 13 );
  if( flags & 0x1000 ) dump_field( &end, 14 );

  dump_field( &end, 15 );

  /* Dump first 5 chars of prefix, they're always here in no */
  if( g_northern_version )
    dump_field( &end, 2 );
  dump_field( &end, 16 );
}

static void act_on_record( uint8_t * end, uint16_t base ) {
  uint16_t *rec  = (uint16_t*)end;
  uint8_t  *e = end;
  uint16_t num_dwords = rec[0];
  uint16_t flagbytes  = rec[1];
  uint32_t flags = 0;
  int i;

  for (i=0; i<flagbytes; ++i) flags = (flags<<8) | *--end;

//  printf( "-------- %03d: %06X\n", num_dwords, flags );
  for (i = 0; i < num_dwords; i++ ) {
    uint16_t subflag = load_word( e, base, 2*i );
    uint16_t t_off   = load_word( e, base, 2*i+1 );
    uint8_t *rec_start = end - t_off;

    if (i == 0)
      dump_primary( rec_start, flags );
    else {
      uint8_t * rec_end = end - ( ( i+1 == num_dwords ) ? 0 : load_word( e, base, 2*i+3 ) );
      printf( "(%04X): ", subflag );
//      dump_string( rec_start, rec_end, file );
      while ( rec_start < rec_end )
        putchar( cp437_to_iso8859_1_table[ *(rec_start++) ] );
      putchar(10);
    }
  }
  finish_record();
}

int main( int args, char **argv ) {
  char filename[1024];
  MAP data, index;
  uint32_t * indoff;
  size_t limit;
  int i;

  if( args != 3 ) {
    fprintf( stderr, "Syntax: %s <dumpfile> <indexfile>\n", argv[0] );
    exit(1);
  }

  for( i=0; i<g_outfiles; ++i )
  {
    sprintf( filename, "%02d_unknown", i+1 );
    g_state.outfiles[i] = open( filename, O_WRONLY | O_APPEND | O_CREAT, 0644 );
    g_state.outbuf[i]   = malloc(8192*4096);
    g_state.outfill[i]  = 0;
  }

  data  = map_file( argv[1], 1 );
  index = map_file( argv[2], 1 );

  if( !data || !index )
    exit( 1 );

  g_northern_version = data->addr[0x21e] != 5;

  /* Each entry in outfile[0] is flag + \n, i.e. 3 bytes
     We want to flush at ever percent progress */
  limit = 3 * ( ( index->size / 4 ) / 100 );

  for( indoff = (uint32_t*)(index->addr + 8);
       indoff < (uint32_t*)(index->addr + index->size) && *indoff;
       indoff++ ) {
//        printf( "\nActing on record at off: %08X\n", *indoff );
        act_on_record( data->addr + *indoff, *indoff & 0x1fff );

    /* Write out results */
    if( g_state.outfill[0] > limit )
      for( i=0; i<g_outfiles; ++i ) {
        if( g_state.outfill[i] > 1024*1024*6 ) printf( "Large: %zd\n", g_state.outfill[i] );
        write( g_state.outfiles[i], g_state.outbuf[i], g_state.outfill[i] );
        g_state.outfill[i]  = 0;
      }
  }

  for( i=0; i<g_outfiles; ++i ) {
    write( g_state.outfiles[i], g_state.outbuf[i], g_state.outfill[i] );
    close( g_state.outfiles[i] );
  }
  unmap_file( &data );
  unmap_file( &index );

}