#include <stdio.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <simplemd5.h>
#include "dict.h"

static FILE *fp = NULL;
static int lock = 0;
static char* filepath;
static uint8_t* dict_md5;

#ifdef CPUBIT64
    #define _dict_md5_2 ((uint64_t*)dict_md5)
#else
    #define _dict_md5_4 ((uint32_t*)dict_md5)
#endif


static int fill_md5() {
    size_t size = get_dict_size();
    uint8_t* dict_buff = (uint8_t*)malloc(size);
    if(dict_buff) {
        rewind(fp);
        if(fread(dict_buff, size, 1, fp) == 1) {
            if(dict_md5) free(dict_md5);
            dict_md5 = md5(dict_buff, size);
            free(dict_buff);
            return 1;
        } else {
            free(dict_buff);
            puts("Read dict error");
            return 0;
        }
    } else {
        puts("Allocate memory error");
        return 0; 
    }
}

uint32_t last_nonnull(char* p, uint32_t max_size) {
    if(max_size > 1) while(!p[max_size - 1]) max_size--;
    return max_size;
}

int init_dict(char* file_path) {
    fp = fopen(file_path, "rb+");
    if(fp) {
        lock = LOCK_UN;
        filepath = file_path;
        return fill_md5();
    } else {
        puts("Open dict error");
        return 0;
    }
}

FILE *open_dict(int lock_type) {
    if(lock & LOCK_EX) return NULL;
    else {
        if(!fp) fp = fopen(filepath, "rb+");
        if(fp) {
            lock = lock_type;
            fill_md5();
            rewind(fp);
            return fp;
        } else {
            puts("Open dict error");
            return NULL;
        }
    }
}

void close_dict() {
    puts("Close dict");
    lock = LOCK_UN;
}

off_t get_dict_size() {
    struct stat statbuf;
    if(stat(filepath, &statbuf)==0) return statbuf.st_size;
    else return -1;
}

int is_md5_equal(uint8_t* digest) {
    #ifdef CPUBIT64
        uint64_t* digest2 = (uint64_t*)digest;
        return (digest2[0] == _dict_md5_2[0]) &&
                (digest2[1] == _dict_md5_2[1]);
    #else
        uint32_t* digest4 = (uint32_t*)digest;
        return (digest4[0] == _dict_md5_4[0]) &&
                (digest4[1] == _dict_md5_4[1]) &&
                (digest4[2] == _dict_md5_4[2]) &&
                (digest4[3] == _dict_md5_4[3]);
    #endif
}