#include "Buffer.h"
#include <stdio.h>
#include "System.h"
#include "File.h"
#include "TextLoader.h"

Buffer::Buffer()
{
    m_file_buffer = nullptr;
    m_file_buffer_size = 0u;
    piece_table = std::make_shared<PieceTable>(nullptr, 0u);
}

Buffer::~Buffer()
{
    if (m_file_buffer != nullptr)
    {
        free_file_buffer();
    }
}

bool Buffer::load_from_file(const char * filename)
{
    File file;
    if (!file.open(filename))
    {
        return false;
    }

    size_t file_size = file.get_size();
    if (file_size < 0)
    {
        return false;
    }

    m_file_buffer_size = ((unsigned long)file_size + System::page_size - 1u) & System::page_base_mask;
    m_file_buffer = (uint8_t *)System::alloc_pages(m_file_buffer_size >> System::page_size_log);
    if (m_file_buffer == NULL)
    {
        return false;
    }

    if (!file.read(m_file_buffer, file_size))
    {
        free_file_buffer();
        return false;
    }

    TextLoader text_loader;
    text_loader.load_buffer(m_file_buffer, file_size);

    piece_table = std::make_shared<PieceTable>(m_file_buffer, m_file_buffer_size);
    for (auto it = text_loader.begin(); it != text_loader.end(); it++)
    {
        /* TODO: correctly calculate n_chars based on current file encoding. */
        piece_table->append_initial_line_piece(it->first, it->second, it->second);
    }

    return true;
}

void Buffer::free_file_buffer()
{
    System::free_pages(m_file_buffer, m_file_buffer_size >> System::page_size_log);
    m_file_buffer = nullptr;
    m_file_buffer_size = 0u;
}