#include "io.h"
#include "common.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

file_t* file_open(const char* filename, const char* mode, size_t page_size)
{
    FILE* handle = fopen(filename, mode);

    if (!handle) {
        printfv(VERBOSITY_NORMAL, "Can't open file %s.\n", filename);
        return NULL;
    }

    printfv(VERBOSITY_DEBUG, "File %s opened in %s with page size %zu.\n", filename, mode, page_size);
    file_t* result = malloc(sizeof(file_t));

    result->page_size = page_size;
    result->file      = handle;
    result->filename  = malloc(strlen(filename) + 1); 
    result->buffer    = malloc(page_size);

    strcpy(result->filename, filename);

    return result;
}

void file_close(file_t* file)
{
    printfv(VERBOSITY_DEBUG, "Closing file %s.\n", file->filename);
    fclose(file->file);

    free(file->filename);
    free(file->buffer);
    free(file);
}

size_t file_read(file_t* file, unsigned block, void* buffer, size_t length)
{
    memset(file->buffer, 0, file->page_size);

    printfv(VERBOSITY_DEBUG, "Reading page %u of %s.\n", block, file->filename);

    fseek(file->file, block * file->page_size, SEEK_SET);
    int read = fread(file->buffer, 1, file->page_size, file->file); 
    memcpy(buffer, file->buffer, length);
    return read;
}

size_t file_write(file_t* file, unsigned block, const void* buffer, size_t length)
{
    memset(file->buffer, 0, file->page_size);
    memcpy(file->buffer, buffer, length);

    printfv(VERBOSITY_DEBUG, "Writing page %u to %s. (%zu bytes)\n", block, file->filename, length);
    fseek(file->file, block * file->page_size, SEEK_SET);
    return fwrite(file->buffer, 1, file->page_size, file->file); 
}