/**
 * rofi
 *
 * MIT/X11 License
 * Copyright 2013-2014 Qball  Cow <qball@gmpclient.org>
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <errno.h>
#include "rofi.h"
#include "history.h"

#define HISTORY_NAME_LENGTH 256
#define HISTORY_MAX_ENTRIES  25

typedef struct __element
{
    long int index;
    char     name[HISTORY_NAME_LENGTH];
}_element;

static int __element_sort_func ( const void *ea, const void *eb )
{
    _element *a = *(_element * *) ea;
    _element *b = *(_element * *) eb;
    return b->index - a->index;
}

static void __history_write_element_list( FILE *fd, _element **list, unsigned int length)
{
    if(list == NULL) {
        return;
    }
    // Sort the list before writing out.
    qsort ( list, length, sizeof ( _element* ), __element_sort_func );

    // Set the max length of the list.
    length = (length > HISTORY_MAX_ENTRIES)? HISTORY_MAX_ENTRIES:length;

    // Write out entries.
    for(unsigned int iter = 0; iter < length ;iter++)
    {
        fprintf(fd , "%ld %s\n", list[iter]->index, list[iter]->name);
    } 
}

static _element ** __history_get_element_list ( FILE *fd, unsigned int *length )
{
    _element **retv = NULL;

    if  (length == NULL)
    {
        return NULL;
    }
    *length = 0;

    if( fd == NULL)
    {
        return NULL;
    }
    char buffer[HISTORY_NAME_LENGTH+16];
    while ( fgets (buffer, HISTORY_NAME_LENGTH+16, fd ) != NULL)
    {
        // Skip empty lines.
        if ( strlen ( buffer ) == 0 )
        {
            continue;
        }
        retv         = reallocate ( retv, ( *length + 2 ) * sizeof ( _element* ) );
        retv[(*length)]  = allocate ( sizeof ( _element ) );
        // remove trailing \n
        buffer[strlen ( buffer ) - 1] = '\0';
        // Parse the number of times.
        char * start = NULL;
        retv[(*length)]->index = strtol ( buffer, &start, 10 );
        strncpy(retv[(*length)]->name, (start+1),HISTORY_NAME_LENGTH);
        // Force trailing '\0'
        retv[(*length)]->name[HISTORY_NAME_LENGTH-1] = '\0';
        retv[(*length) + 1] = NULL;

        (*length)++;
    }
    return retv;
}


void history_set ( const char *filename, const char *entry )
{
    int found = 0;
    unsigned int curr   = 0;
    unsigned int length = 0;
    // Open file for reading and writing.
    FILE *fd = fopen(filename, "a+");
    if(fd == NULL) 
    {
        fprintf(stderr, "Failed to open file: %s\n", strerror(errno));
        return ;
    }
    // Get list.
    _element ** list = __history_get_element_list(fd, &length);
   
    // Look if the entry exists. 
    for(unsigned int iter = 0;!found && iter < length; iter++)
    {
        if(strcmp(list[iter]->name, entry) == 0)
        {
            curr = iter;
            found = 1;
        }
    }

    if(found) {
        // If exists, increment list index number
        list[curr]->index++;
    }else{
        // If not exists, add it.
        // Increase list by one
        list = reallocate(list,(length+2)*sizeof(_element *));
        list[length] = allocate(sizeof(_element));
        // Copy name
        strncpy(list[length]->name, entry, HISTORY_NAME_LENGTH);
        list[length]->name[HISTORY_NAME_LENGTH-1] = '\0';
        // set # hits
        list[length]->index = 1;

        length++;
        list[length] = NULL;
    }

    // Rewind.
    fseek(fd, 0L, SEEK_SET);
    // Clear file.
    if ( ftruncate(fileno(fd), 0) == 0)
    {
        // Write list.
        __history_write_element_list(fd, list, length);
    }else {
        fprintf(stderr, "Failed to truncate file: %s\n", strerror(errno));
    }
    // Free the list.
    for(unsigned int iter = 0; iter < length; iter++)
    {
        if(list[iter] != NULL) { free(list[iter]); }
    }
    if(list != NULL) free(list);
    // Close file.
    fclose(fd);
}

void history_remove ( const char *filename, const char *entry )
{
    int found = 0;
    unsigned int curr   = 0;
    unsigned int length = 0;
    // Open file for reading and writing.
    FILE *fd = fopen(filename, "a+");
    if(fd == NULL) 
    {
        fprintf(stderr, "Failed to open file: %s\n", strerror(errno));
        return ;
    }
    // Get list.
    _element ** list = __history_get_element_list(fd, &length);
   
    // Find entry. 
    for(unsigned int iter = 0;!found && iter < length; iter++)
    {
        if(strcmp(list[iter]->name, entry) == 0)
        {
            curr = iter;
            found = 1;
        }
    }

    // If found, remove it and write out new file.
    if(found) {
        // Remove the entry.
        free(list[curr]);
        // Swap last to here (if list is size 1, we just swap empty sets).
        list[curr] = list[length-1];
        // Empty last.
        list[length-1] = NULL;
        length--;

        // Rewind.
        fseek(fd, 0L, SEEK_SET);
        // Clear list.
        if(ftruncate(fileno(fd), 0) == 0) {
            // Write list.
            __history_write_element_list(fd, list, length);
        } else {
            fprintf(stderr, "Failed to open file: %s\n", strerror(errno));
        }
    }

    // Free the list.
    for(unsigned int iter = 0; iter < length; iter++)
    {
        if(list[iter] != NULL) { free(list[iter]); }
    }
    if(list != NULL) free(list);
    // Close file.
    fclose(fd);
}

char ** history_get_list ( const char *filename, unsigned int *length )
{
    char **retv = NULL;
    // Open file.
    FILE *fd = fopen(filename, "r");
    if(fd == NULL) 
    {
        if(errno != ENOENT) {
            fprintf(stderr, "Failed to open file: %s\n", strerror(errno));
        }
        return NULL;
    }
    // Get list.
    _element ** list = __history_get_element_list(fd, length);

    // Copy list in right format. 
    if((*length) > 0 )
    {
        retv = allocate(((*length)+1)*sizeof(char *));
        for ( int iter = 0; iter < (*length); iter++)
        {
            retv[iter] = strdup(list[iter]->name); 
            free(list[iter]);
        }
        retv[(*length)] = NULL;
        free(list);
    }

    fclose(fd);
    return retv;
}