#include "TextLoader.h"
#include <stdint.h>

/** Create a TextLoader. */
TextLoader::TextLoader()
{
    m_line_endings = LineEndings::LF;
    m_lines = NULL;
    m_eol_at_eof = true;
}

/**
 * Scan text to detect line endings and record their positions.
 *
 * @param buffer Buffer containing the text to import.
 * @param size Size of the buffer.
 */
void TextLoader::load_buffer(uint8_t * buffer, size_t size)
{
    std::shared_ptr<std::list<Span>> lines[LineEndings::COUNT];
    size_t line_start[LineEndings::COUNT] = {0};
    unsigned int n_cr = 0;
    unsigned int n_lf = 0;
    bool crlf = true;
    for (size_t i = 0; i < LineEndings::COUNT; i++)
    {
        lines[i] = std::make_shared<std::list<Span>>();
    }
    for (size_t i = 0; i < size; i++)
    {
        if (buffer[i] == '\r')
        {
            lines[LineEndings::CR]->push_back(Span(&buffer[line_start[LineEndings::CR]], i - line_start[LineEndings::CR]));
            n_cr++;
            line_start[LineEndings::CR] = i + 1;
            if (crlf)
            {
                if ((i < (size - 1)) && (buffer[i + 1] == '\n'))
                {
                    lines[LineEndings::CRLF]->push_back(Span(&buffer[line_start[LineEndings::CRLF]], i - line_start[LineEndings::CRLF]));
                    n_lf++;
                    i++;
                    line_start[LineEndings::CRLF] = i + 1;
                }
                else
                {
                    crlf = false;
                }
            }
        }
        else if (buffer[i] == '\n')
        {
            lines[LineEndings::LF]->push_back(Span(&buffer[line_start[LineEndings::LF]], i - line_start[LineEndings::LF]));
            crlf = false;
            n_lf++;
            line_start[LineEndings::LF] = i + 1;
        }
    }

    if (crlf && (n_lf > 0u))
    {
        m_line_endings = LineEndings::CRLF;
    }
    else if ((n_cr > 0u) && (n_lf == 0u))
    {
        m_line_endings = LineEndings::CR;
    }
    else
    {
        m_line_endings = LineEndings::LF;
    }

    m_lines = lines[m_line_endings];

    /* Check if there is a line that was not terminated by a EOL sequence at
     * the end of the file. */
    if (line_start[m_line_endings] < size)
    {
        m_lines->push_back(Span(&buffer[line_start[m_line_endings]], size - line_start[m_line_endings]));
        m_eol_at_eof = false;
    }
}