#include <luna/Alloc.h>
#include <luna/CString.h>
#include <luna/String.h>

String::String()
{
    m_inline = true;
    m_length = 0;
    memset(m_inline_storage, 0, sizeof(m_inline_storage));
}

String::String(String&& other)
{
    m_inline = other.m_inline;

    m_string = other.m_string;
    m_length = other.m_length;

    if (m_inline) memcpy(m_inline_storage, other.m_inline_storage, sizeof(m_inline_storage));

    other.m_string = nullptr;
}

String::String(char* c_str)
{
    check(c_str);
    m_string = c_str;
    m_inline = false;
    m_length = strlen(m_string);
}

String::String(char* c_str, usize length)
{
    check(c_str);
    m_string = c_str;
    m_inline = false;
    m_length = length;
}

String::~String()
{
    if (!m_inline) free_impl(m_string);
}

Result<String> String::clone() const
{
    return from_string_literal(chars());
}

Result<String> String::substring(usize begin, usize size) const
{
    if (begin + size >= size) return err(EINVAL);
    char* const dup = strndup(chars() + begin, size);
    if (!dup) return err(ENOMEM);
    return String { dup, size };
}

const char& String::operator[](usize index) const
{
    expect(index < m_length, "index out of range");
    return chars()[index];
}

Result<String> String::from_string_literal(const char* str)
{
    usize len = strlen(str);
    if (len < sizeof(m_inline_storage))
    {
        String result;
        result.m_inline = true;
        result.m_length = len;
        strncpy(result.m_inline_storage, str, sizeof(m_inline_storage));
        return result;
    }

    char* const dup = strdup(str);
    if (!dup) return err(ENOMEM);
    return String { dup };
}