#include 
#include 
#include 
#include 
#include 

// OS-specific libraries.
#include 
#include 

#include "ansi_code.hpp"
#include "common.hpp"
#include "input_output.hpp"
#include "terminal_pager.hpp"

terminal_pager::terminal_pager()
    : m_rows(0)
    , m_columns(0)
    , m_start_row_index(0)
{
    maybe_grab_cout();
}

terminal_pager::~terminal_pager()
{
    release_cout();
}

std::string terminal_pager::get_input() const
{
    // Blocks until input received.
    std::string str;
    char ch;
    std::cin.get(ch);
    str += ch;

    if (ansi_code::is_escape_char(ch))  // Start of ANSI escape sequence.
    {
        do
        {
            std::cin.get(ch);
            str += ch;
        } while (!std::isalpha(ch));  // ANSI escape sequence ends with a letter.
    }

    return str;
}

void terminal_pager::maybe_grab_cout()
{
    // Unfortunately need to access _internal namespace of termcolor to check if a tty.
    if (termcolor::_internal::is_atty(std::cout))
    {
        // Should we do anything with cerr?
        m_cout_rdbuf = std::cout.rdbuf(&m_stringbuf);
    }
    else
    {
        m_cout_rdbuf = std::cout.rdbuf();
    }
}

bool terminal_pager::process_input(std::string input)
{
    if (input.size() == 0)
    {
        return true;
    }

    switch (input[0])
    {
        case 'q':
        case 'Q':
            return true;  // Exit pager.
        case 'u':
        case 'U':
            scroll(true, true);  // Up a page.
            return false;
        case 'd':
        case 'D':
        case ' ':
            scroll(false, true);  // Down a page.
            return false;
        case '\n':
            scroll(false, false);  // Down a line.
            return false;
        case '\e':  // ANSI escape sequence.
            // Cannot switch on a std::string.
            if (ansi_code::is_up_arrow(input))
            {
                scroll(true, false);  // Up a line.
                return false;
            }
            else if (ansi_code::is_down_arrow(input))
            {
                scroll(false, false);  // Down a line.
                return false;
            }
    }

    std::cout