/**
 * @file InputField.cpp
 * @author apio (cloudapio.eu)
 * @brief Single line text input widget.
 *
 * @copyright Copyright (c) 2024, the Luna authors.
 *
 */

#include <ctype.h>
#include <luna/String.h>
#include <luna/StringView.h>
#include <luna/Utf8.h>
#include <ui/InputField.h>

namespace ui
{
    InputField::InputField(SharedPtr<ui::Font> font) : ui::TextInput(), m_font(font)
    {
    }

    Result<ui::EventResult> InputField::handle_key_event(const ui::KeyEventRequest& request)
    {
        // Avoid handling "key released" events
        if (!request.pressed) return ui::EventResult::DidNotHandle;

        if (request.code == moon::K_LeftArrow)
        {
            if (m_cursor > 0) m_cursor--;
            else
                return ui::EventResult::DidNotHandle;
            update_cursor();
            return ui::EventResult::DidHandle;
        }

        if (request.code == moon::K_RightArrow)
        {
            if (m_cursor < m_data.size()) m_cursor++;
            else
                return ui::EventResult::DidNotHandle;
            update_cursor();
            return ui::EventResult::DidHandle;
        }

        if (request.code == moon::K_Backspace)
        {
            if (m_cursor == 0) return ui::EventResult::DidNotHandle;
            m_cursor--;

            delete_current_character();

            update_cursor();

            return ui::EventResult::DidHandle;
        }

        if (request.letter == '\n')
        {
            if (m_has_on_submit_action)
            {
                m_on_submit_action(data());
                return ui::EventResult::DidHandle;
            }

            return ui::EventResult::DidNotHandle;
        }

        if (iscntrl(request.letter)) return ui::EventResult::DidNotHandle;

        if (m_cursor == m_data.size()) TRY(m_data.append_data((const u8*)&request.letter, 1));
        else
            TRY(insert_character(request.letter));

        m_cursor++;

        update_cursor();

        return ui::EventResult::DidHandle;
    }

    Result<void> InputField::draw(ui::Canvas& canvas)
    {
        int visible_characters = canvas.width / m_font->width();

        auto string = data();

        Utf8StringDecoder decoder(string.chars());
        wchar_t buf[4096];
        decoder.decode(buf, sizeof(buf)).release_value();

        int characters_to_render = (int)wcslen(buf);

        for (int j = 0; j < visible_characters && j < characters_to_render; j++)
        {
            auto subcanvas = canvas.subcanvas({ j * m_font->width(), 0, m_font->width(), m_font->height() });
            m_font->render(buf[j], ui::WHITE, subcanvas);
        }

        // Draw the cursor
        if ((int)m_cursor < visible_characters && m_cursor_activated)
        {
            canvas.subcanvas({ (int)m_cursor * m_font->width(), 0, 1, m_font->height() }).fill(ui::WHITE);
        }

        return {};
    }

    StringView InputField::data()
    {
        return StringView { (const char*)m_data.data(), m_data.size() };
    }
}