#define _FILE_OFFSET_BITS 64
#define _LARGEFILE_SOURCE
#define _GNU_SOURCE /* for strnlen */
#define HAS_READLINE /* remove if you don't have readline */

//#define DEBUG

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <inttypes.h>
#include <zlib.h>
#ifdef HAS_READLINE
#include <readline/readline.h>
#endif
#include "viewhtml.h"

#ifdef DEBUG
#  define debug(...) fprintf(stderr, __VA_ARGS__)
#else
#  define debug(...) do {} while (0)
#endif

typedef enum {
    MDE_Success = 0,
    MDE_BadSignature,
    MDE_TruncatedFile,
    MDE_OutOfMemory,
    MDE_InternalError,
    MDE_DecompressionFailed,
    MDE_InvalidData,
    MDE_EntryNotFound,
} MDError;

const char *const mde_string[] = {
    "Success",
    "Bad signature",
    "Truncated file",
    "Out of memory",
    "Internal error",
    "Decompression failed",
    "Invalid data",
    "Entry not found",
};

typedef struct {
    uint32_t metadata_checksum; // guess
    uint32_t unknown2;  // 0
    uint32_t index_entries;
    uint32_t unknown4;  // 0
    uint32_t num_entries;
    uint32_t unknown6;  // 0
    uint32_t index_memsize;
    uint32_t unknown8;  // 0
    uint32_t index_containersize; // compressed size + 8
    uint32_t unknown10; // 0
    uint32_t unknown11; // 0x37
    uint32_t unknown12; // 0x05 0xEE 0x00 0x9F (checksum?)
    uint32_t unknown13; // 0x02 0x00 0x00 0x00
    uint32_t unknown14; // 0x0B 0x6C 0x09 0x7E
} MDHeader;

typedef struct {
    char *last_word;
    uint32_t unknown1; // 0
    uint32_t compressed_size;
    uint32_t unknown3; // 0
    uint32_t uncompressed_size; // uncompressed size? 0xFFFD
    uint32_t unknown5; // 0
    uint32_t unknown6; // 0x93D -- number of entries in block?
    char *next_word;
    
    off_t offset;
} MDIndexEntry;

typedef struct {
    uint32_t unknown1; // 0
    uint32_t unknown2; // 0x95AC
    uint32_t unknown3; // 0
    uint32_t unknown4; // 0x247809
    uint32_t unknown5; // 0
    uint32_t disksize;
    uint32_t unknown7; // 0
    uint32_t unknown8; // 0xAC6FBFF7 (checksum?)
} MDLengthsHeader;

typedef struct {
    uint32_t unknown1; // or high-order bits in 64-bit number?
    uint32_t disk_size;
    uint32_t unknown3; // ditto
    uint32_t mem_size;
} MDLengthsEntry;

typedef struct {
    off_t disk;
    off_t mem;
} MDOffsetsInfo;

typedef struct {
    MDHeader header;
    MDIndexEntry *index;
    //size_t length_entries;
    MDLengthsHeader lengths_header;
    MDLengthsEntry *lengths;
    MDOffsetsInfo *offsets;
    off_t header_end;
    //off_t lengths_start;
    off_t articles_start;
} MDFile;

#define check(retval) do { error = (retval); if (error != MDE_Success) return error; } while (false)

static uint64_t byteswap64(uint64_t word) {
    return (word & 0xFF) << 56 |
           (word & 0xFF00) << 40 |
           (word & 0xFF0000) << 24 |
           (word & 0xFF000000) << 8 |
           (word & 0xFF00000000) >> 8 |
           (word & 0xFF0000000000) >> 24 |
           (word & 0xFF000000000000) >> 40 |
           (word & 0xFF00000000000000) >> 56;
}

static void byteswap32_var(uint32_t *word) {
    *word = (*word & 0xFF) << 24 |
            (*word & 0xFF00) << 8 |
            (*word & 0xFF0000) >> 8 |
            (*word & 0xFF000000) >> 24;
}

static uint32_t byteswap32(uint32_t word) {
    return (word & 0xFF) << 24 |
           (word & 0xFF00) << 8 |
           (word & 0xFF0000) >> 8 |
           (word & 0xFF000000) >> 24;
}

static uint16_t byteswap16(uint16_t word) {
    return (word & 0xFF) << 8 |
           (word & 0xFF00) >> 8;
}

static MDError get16(const uint8_t *data, const size_t len, size_t *offset, uint16_t *word) {
    if (*offset + sizeof(*word) > len) return MDE_TruncatedFile;
    *word = byteswap16(*(uint16_t*)(data+*offset));
    *offset += sizeof(*word);
    return MDE_Success;
}

static MDError get32(const uint8_t *data, const size_t len, size_t *offset, uint32_t *word) {
    if (*offset + sizeof(*word) > len) return MDE_TruncatedFile;
    *word = byteswap32(*(uint32_t*)(data+*offset));
    *offset += sizeof(*word);
    return MDE_Success;
}

static MDError getstring(const uint8_t *data, const size_t len, size_t *offset,
                         size_t stringlen, char **string) {
    if (*offset + stringlen+1 > len) return MDE_TruncatedFile;
    if (data[*offset+stringlen] != 0) return MDE_InvalidData;
    *string = malloc(stringlen+1);
    if (!*string) return MDE_OutOfMemory;
    memcpy(*string, (char*)(data+*offset), stringlen+1);
    *offset += stringlen+1;
    return MDE_Success;
}

static int mdstrcmp(const char *sa, const char *sb) {
    const unsigned char *a = (const unsigned char*)sa;
    const unsigned char *b = (const unsigned char*)sb;
    static const char punct[] = " !\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~";
    
    for (; *a && *b; a++, b++) {
        unsigned char c = tolower(*a);
        unsigned char d = tolower(*b);
        
        // Binary equality (after converting to lowercase)
        //fprintf(stderr, "%c %c\n", c, d);
        if (c == d) continue;
        
        // Ignore spaces and punctuation
        while (a[0] && strchr(punct, a[0])) a++;
        while (b[0] && strchr(punct, b[0])) b++;
        
        c = tolower(*a);
        d = tolower(*b);
        if (c == d) continue;
        else return ((int)c) - ((int)d);
    }
    
    // Ignore trailing spaces and punctuation
    while (a[0] && strchr(punct, a[0])) a++;
    while (b[0] && strchr(punct, b[0])) b++;
    
    return ((int)*a) - ((int)*b);
}
/*
static int sign(int n) {
    if (n < 0) return -1;
    if (n > 0) return 1;
    else return 0;
}

static int mdstrcmp(const char *a, const char *b) {
    int i = strcasecmp(a, b);
    int j = _mdstrcmp(a, b);
    
    debug("strcasecmp %3d,   _mdstrcmp %3d\n", i, j);
    if (sign(i) != sign(j)) {
        debug("    %s\n    %s\n", a, b);
        abort();
    }
    return i;
}*/

MDError read_signature(FILE *input) {
    uint16_t signature;
    
    if (fread(&signature, 2, 1, input) != 1) return MDE_BadSignature;
    if (signature != 0) return MDE_BadSignature;
    
    return MDE_Success;
}

MDError skip_metadata(FILE *input) {
    uint16_t ucs2char;
    
    do {
        if (fread(&ucs2char, 2, 1, input) != 1) return MDE_TruncatedFile;
    } while (ucs2char != 0);
    
    return MDE_Success;
}

MDError read_header(FILE *input, MDHeader *header) {
    if (fread(header, sizeof(MDHeader), 1, input) == 1) {
        /* Byte-swap */
        for (size_t i = 0; i < sizeof(MDHeader)/4; i++) {
            byteswap32_var(((uint32_t*)header)+i);
        }
        return MDE_Success;
    }
    return MDE_TruncatedFile;
}

MDError parse_index_entry(const MDFile *file, uint8_t *data, bool last,
                          size_t *offset, MDIndexEntry *entry) {
    MDError error;
    uint16_t namelen;
    size_t len = file->header.index_memsize;
    
    check(get16(data, len, offset, &namelen));
    check(getstring(data, len, offset, namelen, &entry->last_word));
    //debug("from: %s\n", entry->last_word);
    
    check(get32(data, len, offset, &entry->unknown1));
    check(get32(data, len, offset, &entry->compressed_size));
    check(get32(data, len, offset, &entry->unknown3));
    check(get32(data, len, offset, &entry->uncompressed_size));
    
    if (last) {
        /* Last entry, so skip the next-entry stuff */
        entry->unknown5 = entry->unknown6 = 0;
        entry->next_word = NULL;
        return MDE_Success;
    }
    
    check(get32(data, len, offset, &entry->unknown5));
    check(get32(data, len, offset, &entry->unknown6));
    
    check(get16(data, len, offset, &namelen));
    check(getstring(data, len, offset, namelen, &entry->next_word));
    //debug("from: %s to: %s\n", entry->last_word, entry->next_word);
    
    return MDE_Success;
}

MDError read_index(FILE *input, MDFile *file) {
    MDError error;
    uint8_t *index = malloc(file->header.index_memsize);
    if (!index) return MDE_OutOfMemory;
    
    // Hack
    uLongf usize = file->header.index_memsize;
    int csize = file->header.index_containersize - 8;
    uint8_t *compressed = malloc(csize);
    if (!compressed) {
        free(index);
        return MDE_OutOfMemory;
    }
    if (fread(compressed, csize, 1, input) != 1) {
        free(compressed);
        free(index);
        return MDE_TruncatedFile;
    }
    //debug("compr crc32: %lx\n", crc32(0, compressed, csize));
    //for (int i = 0; i < csize; i++) debug("%hx ", compressed[i]);
    int zstatus = uncompress(index, &usize,
                             compressed, csize);
    free(compressed);
    if (zstatus != Z_OK) {
        free(index);
        return MDE_DecompressionFailed;
    }
    
    //file->index_count = byteswap32(*(uint32_t*)(index+4));
    
    debug("unknown value: %d\n", byteswap32(*(uint32_t*)(index+4)));
    debug("uncompr crc32: %lx\n", crc32(0, index, usize));
    debug("      adler32: %lx\n", adler32(0, index, usize));
    
    file->index = malloc((file->header.index_entries)*sizeof(MDIndexEntry));
    if (!file->index) {
        free(index);
        return MDE_OutOfMemory;
    }
    size_t offset = 11;
    off_t dataptr = ftello(input);
    for (size_t i = 0; i < file->header.index_entries; i++) {
        //debug("parsing entry %d. dataptr = %qd\n", i, dataptr);
        check(parse_index_entry(file, index, (i == file->header.index_entries-1),
                                &offset, &file->index[i]));
        file->index[i].offset = dataptr+8;
        dataptr += file->index[i].compressed_size;
    }
    
    return MDE_Success;
}

MDError get_block_number(const MDFile *file, const char *word, size_t *number) {
    const char *first_word = "";
    size_t i;
    for (i = 0; i < file->header.index_entries; i++) {
        /*printf("test[%d] %s in (%s %s) = (%d %d)\n", i,
               word, file->index[i].last_word, file->index[i].next_word,
               mdstrcmp(word, file->index[i].last_word),
               mdstrcmp(word, file->index[i].next_word));*/

//        debug("compare %20s < %20s < %20s\n", first_word, word, file->index[i].last_word);
        if (mdstrcmp(word, first_word) < 0) {
            fprintf(stderr, "can't get block number\n");
            return MDE_EntryNotFound;
        }
        
        if (mdstrcmp(word, file->index[i].last_word) <= 0) {
            debug("matching block %d\n", i);
            *number = i;
            return MDE_Success;
        }
        
        first_word = file->index[i].next_word;
    }
    return MDE_EntryNotFound;
}

MDError get_block(FILE *input, const MDIndexEntry *entry,
                  uint8_t **block, size_t *blocklen) {
    uLongf usize = entry->uncompressed_size;
    
    fseeko(input, entry->offset, SEEK_SET);
    
    debug("        unkn1: %8d\n"
          "   compressed: %8d\n"
          "        unkn3: %8d\n"
          " uncompressed: %8d\n"
          "        unkn5: %8d\n"
          "        unkn6: %8d\n", // maybe the difference of the first characters between the first/last word
          entry->unknown1,
          entry->compressed_size,
          entry->unknown3,
          entry->uncompressed_size,
          entry->unknown5,
          entry->unknown6);
    
    uint8_t *compressed = malloc(entry->compressed_size);
    *block = malloc(usize);
    if (!compressed || !*block) {
        free(*block);
        free(compressed);
        return MDE_OutOfMemory;
    }
    debug("reading from %qd (%d bytes)\n", entry->offset, entry->compressed_size);
    if (fread(compressed, entry->compressed_size, 1, input) != 1) {
        free(compressed);
        return MDE_TruncatedFile;
    }
    
    int zstatus = uncompress(*block, &usize,
                             compressed, entry->compressed_size);
    free(compressed);
    if (zstatus != Z_OK) {
        free(*block);
        return MDE_DecompressionFailed;
    }
    
    if ((*block)[usize-1] != 0) {
        free(*block);
        return MDE_InvalidData;
    }
    *blocklen = usize;
    
    return MDE_Success;
}

MDError find_offset_in_block(const MDFile *file, const uint8_t *block, size_t blocklen,
                             const char *name, off_t *offset) {
    size_t blockpos = 0;
    
    /* Parse entries */
    while (blockpos < blocklen) {
        *offset = byteswap64(*(const uint64_t*)(block + blockpos));
        //printf("compare %s %s\n", name, (const char*)(block + blockpos + 8));
        if (!mdstrcmp((const char*)(block + blockpos + 8), name)) return MDE_Success;
        /*if (mdstrcmp((const char*)(block + blockpos + 8), name) > 0) {
            for (const char *c = (char*)(block + blockpos + 8); *c; c++) debug("%hhx[%c] ", *c, *c);
            debug("\n");
            return MDE_EntryNotFound;
        }*/
        blockpos += 8 + strlen((const char*)(block + blockpos + 8)) + 1;
    }
    
    //debug("can't get offset in block\n");
    return MDE_EntryNotFound;
}

MDError get_length_entry_number(const MDFile *file, off_t offset, size_t *entry_number) {
    for (size_t i = 0; i < file->lengths_header.disksize/sizeof(MDLengthsEntry); i++) {
        off_t start = file->offsets[i].mem;
        if ((offset >= start) && (offset < start + file->lengths[i].mem_size)) {
            *entry_number = i;
            return MDE_Success;
        }
    }
    fprintf(stderr, "Could not look up offset in lengths table\n");
    return MDE_EntryNotFound;
}

MDError read_lengthtables(FILE *input, MDFile *file) {
    off_t blocks_end = file->index[file->header.index_entries-1].offset + file->index[file->header.index_entries-1].compressed_size-8;
    
    /* Read header */
    if ((fseeko(input, blocks_end, SEEK_SET) == -1) ||
        (fread(&file->lengths_header, sizeof(MDLengthsHeader), 1, input) != 1)) {
        return MDE_TruncatedFile;
    }
    
    /* Byte-swap */
    for (size_t i = 0; i < sizeof(MDLengthsHeader)/4; i++) {
        byteswap32_var(((uint32_t*)&file->lengths_header)+i);
    }
    
    //file->lengths_start = blocks_end + sizeof(MDLengthsHeader);
    file->articles_start = blocks_end + sizeof(MDLengthsHeader) +
                           file->lengths_header.disksize;
    size_t count = file->lengths_header.disksize/sizeof(MDLengthsEntry);
    
    /* Read all length entries */
    //if (lengths_header.disksize != sizeof(MDLengthsEntry)*length_header)
    file->lengths = malloc(file->lengths_header.disksize);
    file->offsets = malloc(count*sizeof(MDOffsetsInfo));
    if (!file->lengths || !file->offsets) {
        return MDE_OutOfMemory;
    }
    if (fread(file->lengths, file->lengths_header.disksize, 1, input) != 1) {
        free(file->lengths);
        return MDE_TruncatedFile;
    }
    
    off_t disk_offset = file->articles_start;
    off_t mem_offset = 0;
    for (size_t i = 0; i < count; i++) {
        /* Byte-swap */
        byteswap32_var(&file->lengths[i].mem_size);
        byteswap32_var(&file->lengths[i].disk_size);
        
        /* Calculate offsets */
        file->offsets[i].disk = disk_offset + 8;
        file->offsets[i].mem = mem_offset;
        disk_offset += file->lengths[i].disk_size;
        mem_offset += file->lengths[i].mem_size;
    }
    
    return MDE_Success;
}

#if 0
// FIXME behöver läsa in alla längder för att få fram filpositioner
MDError get_bookshelf_lengths(FILE *input, const MDFile *file,
                             size_t bookshelf_number,
                             MDLengthsEntry *lengths) {
    
    if ((fseeko(input, file->lengths_start + bookshelf_number*sizeof(MDLengthsEntry), SEEK_SET) == -1) ||
        (fread(lengths, sizeof(MDLengthsEntry), 1, input) != 1)) {
        return MDE_TruncatedFile;
    }
    
    /* Byte-swap */
    for (size_t i = 0; i < sizeof(MDLengthsEntry)/4; i++) {
        byteswap32_var(((uint32_t*)lengths)+i);
    }
    
    return MDE_Success;
}
#endif

MDError get_article(FILE *input, const MDFile *file, const char *name,
                    char **article) {
    MDError error;
    uint8_t *block;
    size_t blocklen;
    size_t blocknum;
    MDLengthsEntry *lengths;
    MDOffsetsInfo *offsets;
    
    /* Locate index block */
    check(get_block_number(file, name, &blocknum));
    
    debug("blocknum = %d\n", blocknum);
    check(get_block(input, &file->index[blocknum], &block, &blocklen));
    //fwrite(block, file->index[0].uncompressed_size, 1, stdout);
    
    /* Get article offset/length */
    size_t length_entry_number;
    off_t article_offs;
    check(find_offset_in_block(file, block, blocklen, name, &article_offs));
    check(get_length_entry_number(file, article_offs, &length_entry_number));
    lengths = &file->lengths[length_entry_number];
    offsets = &file->offsets[length_entry_number];
    
    debug("whole_mem_offset = %qd, disk_offset[%d] = %qd (articles_start is %qd)\n", article_offs, length_entry_number, offsets->disk, file->articles_start);
    debug("lengths:  mem %d  disk: %d\n", lengths->mem_size, lengths->disk_size);
    /*printf("article_offs:  %1$qx = %1$qd  (articles_start is %2$qd)\n", article_offs + file->articles_start, file->articles_start);
    printf("    + header:  %1$qx = %1$qd\n", article_offs + file->header_end);
    printf("     + index:  %1$qx = %1$qd\n", article_offs + file->header_end + file->header.index_containersize);
    printf("    + blocks:  %1$qx = %1$qd\n", article_offs + file->index[file->header.index_entries-1].offset + file->index[file->header.index_entries-1].compressed_size-8);
    printf("    relative:  %1$qx = %1$qd\n", article_offs + file->index[blocknum].offset);
    printf("  blocks end:  %1$qx = %1$qd\n", file->index[file->header.index_entries-1].offset + file->index[file->header.index_entries-1].compressed_size-8);*/
    
    if (fseeko(input, offsets->disk, SEEK_SET) == -1) return MDE_TruncatedFile;
    
    //lengths->disk_size += 120000;
    //lengths->mem_size += 1200;
    uint8_t *compressed = malloc(lengths->disk_size);
    uint8_t *articles = malloc(lengths->mem_size);
    if (!compressed || !articles) {
        free(articles);
        free(compressed);
        return MDE_OutOfMemory;
    }
    debug("reading articles (%d bytes)\n", lengths->disk_size);
    if (fread(compressed, lengths->disk_size, 1, input) != 1) {
        free(compressed);
        return MDE_TruncatedFile;
    }
    
    //debug("disksize = %d memsize = %d\n", lengths->disk_size, lengths->mem_size);
    
    uLongf usize = lengths->mem_size;
    int zstatus = uncompress(articles, &usize,
                             compressed, lengths->disk_size);
    free(compressed);
    if (zstatus != Z_OK) {
        fprintf(stderr, "zstatus = %d\n", zstatus);
        free(articles);
        return MDE_DecompressionFailed;
    }
    debug("lengths:  mem %d\n", usize);
    
    /* Extract the right article */
    //article_offs
    size_t internal_offset = article_offs - offsets->mem;
    const char *article_start = (char*)&articles[internal_offset];
    debug("articles = %p  + offs (%d) = %p\n", articles, internal_offset, &articles[internal_offset]);
    size_t article_length = strnlen(article_start, /*lengths->mem_size*/ usize - internal_offset);
    
    *article = malloc(article_length+1);
    memcpy(*article, article_start, article_length);
    (*article)[article_length] = '\0';
    
    return MDE_Success;
}

MDError init_file(FILE *input, MDFile *file) {
    MDError error;
    
    check(read_signature(input));
    check(skip_metadata(input));
    check(read_header(input, &file->header));
    file->header_end = ftello(input);
    
    debug("   meta_csum?: %.8x\n"
          "        unkn2: %8d\n"
          "index entries: %8d\n"
          "        unkn4: %8d\n"
          "  num entries: %8d\n"
          "        unkn6: %8d\n"
          "  index_msize: %8d\n"
          "        unkn8: %8d\n"
          "  index_csize: %8d\n"
          "       unkn10: %8d\n"
          "       unkn11: %8d\n"
          "       unkn12: %.8x\n",
          file->header.metadata_checksum,
          file->header.unknown2,
          file->header.index_entries,
          file->header.unknown4,
          file->header.num_entries,
          file->header.unknown6,
          file->header.index_memsize,
          file->header.unknown8,
          file->header.index_containersize,
          file->header.unknown10,
          file->header.unknown11,
          file->header.unknown12);
    debug("   header end: %8qd\n", file->header_end);
    
    check(read_index(input, file));
    check(read_lengthtables(input, file));
    
    return MDE_Success;
}

MDError list_words(FILE *input, const MDFile *file, const char *beginning) {
    MDError error;
    size_t first_block, last_block;
    const int wordlen = strlen(beginning);
    char last_word[wordlen+2];
    
    check(get_block_number(file, beginning, &first_block));
    memcpy(last_word, beginning, wordlen);
    last_word[wordlen] = '\xFF';
    last_word[wordlen+1] = '\0';
    check(get_block_number(file, last_word, &last_block));
    
    if (last_block - first_block > 2) {
        printf("Too many words begin with those characters.\n");
        return MDE_OutOfMemory;
    }
    
    size_t numNonMonotonic = 0;
    for (size_t blocknum = first_block; blocknum <= last_block; blocknum++) {
        uint8_t *block;
        size_t blocklen;
        check(get_block(input, &file->index[blocknum], &block, &blocklen));
        
        size_t blockpos = 0;
        
        /* Read words from the block */
        const char *previous_word = NULL;
        while (blockpos < blocklen) {
            const char *current_word = (const char*)(block + blockpos + 8);
            
            if (previous_word) {
                int derivative = mdstrcmp(current_word, previous_word);
                if (derivative < 0) {
                    fprintf(stderr, "[warning] string value wasn't monotonic! "
                                "derivative: %d\n", derivative);
                    numNonMonotonic++;
                }
            }
            
            //printf("compare %s %s\n", name, (const char*)(block + blockpos + 8));
            if (mdstrcmp(current_word, beginning) >= 0 &&
                mdstrcmp(current_word, last_word) <= 0) {
                /* Match */
                printf("    %s\n", current_word);
            }
            /*if (mdstrcmp((const char*)(block + blockpos + 8), beginning) > 0) {
                for (const char *c = (char*)(block + blockpos + 8); *c; c++) debug("%hhx[%c] ", *c, *c);
                debug("\n");
                return MDE_EntryNotFound;
            }*/
            previous_word = current_word;
            blockpos += 8 + strlen((const char*)(block + blockpos + 8)) + 1;
        }
    }
    
    if (numNonMonotonic) {
        fprintf(stderr, "[warning] num non-monotonic: %d\n", numNonMonotonic);
    }

    return MDE_Success;
}

#define HIST_SIZE 50

void show_articles(FILE *input, const MDFile *file) {
    size_t hist_id = 0;
    char word_hist[HIST_SIZE][1024];
    memset(word_hist, 0, sizeof(word_hist));
    
    while (true) {
        /* Ask for the article name */
#ifdef HAS_READLINE
        char *word = readline("word> ");
        
        if (!word) break;
#else
        char word[1024];
        
        printf("word> ");
        if (!fgets(word, sizeof(word), stdin)) {
            break;
        }
        
        if (word[0] == '\0') break;
        
        for (char *c = word; *c != '\0'; c++) {
            if (*c == '\n' || *c == '\r') {
                *c = '\0';
                break;
            } else if (*c >= 'A' && *c <= 'Z') {
                *c |= 0x20;
            }
        }
#endif
        
        if (word[0] == '\0') continue;
        
        if (word[0] == '!') {
            /* Search */
            list_words(input, file, &word[1]);
            continue;
        } else if (word[0] == '/') {
            if (strcmp(word, "/hist") == 0) {
                /* Show history list */
                for (size_t i = 0; i < HIST_SIZE; i++) {
                    if (word_hist[i][0] != '\0') {
                        printf("%2d) %.100s\n", i, word_hist[i]);
                    }
                }
                continue;
            } else if (strncmp(word, "/hist ", 6) == 0) {
                /* Go to article in history list */
                size_t i = atoi(&word[6]);
                if (i >= HIST_SIZE || word_hist[i][0] == '\0') {
                    printf("no such entry");
                    continue;
                }
                memcpy(word, word_hist[i], 1024);
            } else {
                printf("invalid command\n");
                continue;
            }
        } else {
            /* Store word in history */
            memcpy(word_hist[hist_id++], word, 1024);
            if (hist_id >= HIST_SIZE) hist_id = 0;
        }
        
        /* Fetch article */
        char *article;
        MDError error = get_article(input, file, word, &article);
        if (error != MDE_Success) {
            printf("%s\n", mde_string[error]);
            continue;
        }
        
        /* Display article */
        //puts(article);
        view_html(article);
        
#ifdef HAS_READLINE
        free(word);
#endif
    }
    printf("\n");
}

int main(int argc, char **argv) {
    int status = 0;
    
    for (int i = 1; i < argc; i++) {
        MDFile file;
        FILE *input = fopen(argv[i], "rb");
        if (!input) {
            perror(argv[i]);
            status = 1;
            continue;
        }
        
        MDError error = init_file(input, &file);
        if (error != MDE_Success) {
            fprintf(stderr, "%s: %s\n", argv[i], mde_string[error]);
            status = 1;
        }
        
        show_articles(input, &file);
        
        fclose(input);
    }
    
    return status;
}