/* SPDX-License-Identifier: Unlicense
 */

#include "chardev.hpp"

#include <cstring>
#include <cstdlib>

static bool startsWith(const char* str, const char* pattern)
{
    const size_t pattern_len = strlen(pattern);
    const size_t str_len = strlen(str);
    if (str_len < pattern_len) {
        return false;
    }
    return 0 == memcmp(str, pattern, pattern_len);
}

static CharDev parseTcp(const char* path)
{
    // We need to make sure there is at least one more ':' delimiter in the
    // string
    const char* rest = strchr(path + (sizeof "tcp:") - 1, ':');
    if (rest == nullptr) {
        return CharDev::Invalid(path);
    }
    const char* port_str;
    // Find last ':' before string ends, i.e. when strchr returns NULL
    do {
        port_str = rest + 1;
        rest = strchr(port_str, ':');
    } while (rest);
    const unsigned long port = strtoul(port_str, nullptr, 0);
    if (port <= UINT16_MAX) {
        path += (sizeof "tcp:") - 1;
        return CharDev::Tcp(path, port_str - 1 - path, port);
    }
    return CharDev::Invalid(path);
}

CharDev CharDev::Parse(const char* path)
{
    if (0 == strcmp(path, "pty")) {
        return CharDev::Pty();
    }
    if (startsWith(path, "tcp:")) {
        return parseTcp(path);
    }
    return CharDev::Invalid(path);
}