#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>

#include <ecp/core.h>
#include <ecp/cr.h>

#include "util.h"

static int _read_key(int fd, uint8_t *key, int *line_cnt) {
    char buffer[ECP_SIZE_ECDH_KEY_BUF];
    char ch;
    int cmt;
    ssize_t rv;
    int _rv;

    if (line_cnt) *line_cnt = 0;
    do {
        cmt = 0;
        rv = read(fd, &ch, 1);
        if (rv == 0) return ECP_ERR_EOF;
        if (rv != 1) return ECP_ERR;
        switch (ch) {
            case '#':
            case '\n': {
                cmt = 1;
                while (ch != '\n') {
                    rv = read(fd, &ch, 1);
                    if (rv == 0) return ECP_ERR_EOF;
                    if (rv != 1) return ECP_ERR;
                }
                if (line_cnt) *line_cnt += 1;
                break;
            }

            default: {
                buffer[0] = ch;
                break;
            }
        }
    } while(cmt);
    if (line_cnt) *line_cnt += 1;

    rv = read(fd, buffer + 1, sizeof(buffer) - 2);
    if (rv < (sizeof(buffer) - 2)) return ECP_ERR;
    buffer[ECP_SIZE_ECDH_KEY_BUF - 1] = '\0';

    do {
        rv = read(fd, &ch, 1);
    } while ((rv == 1) && (ch != '\n'));

    _rv = ecp_str2key(key, buffer);
    return _rv;
}

int ecp_util_read_key(int fd, ecp_ecdh_public_t *public, ecp_ecdh_private_t *private, int *line_cnt) {
    int rv;

    rv = _read_key(fd, (uint8_t *)public, line_cnt);
    if (rv) return rv;

    if (private) {
        rv = _read_key(fd, (uint8_t *)private, line_cnt);
        if (rv) return rv;
    }

    return ECP_OK;
}

int ecp_util_write_key(int fd, ecp_ecdh_public_t *public, ecp_ecdh_private_t *private, int *line_cnt) {
    char buffer[ECP_SIZE_ECDH_KEY_BUF];
    ssize_t rv;

    if (line_cnt) *line_cnt = 0;
    ecp_key2str(buffer, (uint8_t *)public);
    buffer[ECP_SIZE_ECDH_KEY_BUF - 1] = '\n';

    rv = write(fd, buffer, sizeof(buffer));
    if (rv != sizeof(buffer)) return ECP_ERR;
    if (line_cnt) *line_cnt += 1;

    if (private) {
        ecp_key2str(buffer, (uint8_t *)private);
        buffer[ECP_SIZE_ECDH_KEY_BUF - 1] = '\n';

        rv = write(fd, buffer, sizeof(buffer));
        if (rv != sizeof(buffer)) return ECP_ERR;
        if (line_cnt) *line_cnt += 1;
    }

    return ECP_OK;
}

int ecp_util_load_key(char *filename, ecp_ecdh_public_t *public, ecp_ecdh_private_t *private) {
    int rv, fd;

    if ((fd = open(filename, O_RDONLY)) < 0) return ECP_ERR_OPEN;

    rv = ecp_util_read_key(fd, public, private, NULL);
    close(fd);

    if (rv < 0) return rv;
    return ECP_OK;
}

int ecp_util_save_key(char *filename, ecp_ecdh_public_t *public, ecp_ecdh_private_t *private) {
    int rv, fd;

    if ((fd = open(filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR)) < 0) return ECP_ERR_OPEN;

    rv = ecp_util_write_key(fd, public, private, NULL);
    close(fd);

    if (rv < 0) return rv;
    return ECP_OK;
}