/*

 * Copyright (c) 2020-2022, the SerenityOS developers.

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#pragma once

#include <AK/Forward.h>

#include <LibLine/StringMetrics.h>

#include <LibLine/SuggestionManager.h>

namespace Line {

class Editor;

class SuggestionDisplay {

public:

    virtual ~SuggestionDisplay() = default;

    virtual ErrorOr<void> display(SuggestionManager const&) = 0;

    virtual ErrorOr<bool> cleanup() = 0;

    virtual void finish() = 0;

    virtual void set_initial_prompt_lines(size_t) = 0;

    ErrorOr<void> redisplay(SuggestionManager const& manager, size_t lines, size_t columns)

    {

        if (m_is_showing_suggestions) {

            TRY(cleanup());

            set_vt_size(lines, columns);

            TRY(display(manager));

        } else {

            set_vt_size(lines, columns);

        }

        return {};

    }

    virtual void set_vt_size(size_t lines, size_t columns) = 0;

    size_t origin_row() const { return m_origin_row; }

    size_t origin_col() const { return m_origin_column; }

    void set_origin(int row, int col, Badge<Editor>)

    {

        m_origin_row = row;

        m_origin_column = col;

    }

protected:

    void did_display() { m_is_showing_suggestions = true; }

    void did_cleanup() { m_is_showing_suggestions = false; }

    int m_origin_row { 0 };

    int m_origin_column { 0 };

    bool m_is_showing_suggestions { false };

};

class XtermSuggestionDisplay : public SuggestionDisplay {

public:

    XtermSuggestionDisplay(size_t lines, size_t columns)

        : m_num_lines(lines)

        , m_num_columns(columns)

    {

    }

    virtual ~XtermSuggestionDisplay() override = default;

    virtual ErrorOr<void> display(SuggestionManager const&) override;

    virtual ErrorOr<bool> cleanup() override;

    virtual void finish() override

    {

        m_pages.clear();

    }

    virtual void set_initial_prompt_lines(size_t lines) override

    {

        m_prompt_lines_at_suggestion_initiation = lines;

    }

    virtual void set_vt_size(size_t lines, size_t columns) override

    {

        m_num_lines = lines;

        m_num_columns = columns;

        m_pages.clear();

    }

private:

    size_t fit_to_page_boundary(size_t selection_index);

    size_t m_lines_used_for_last_suggestions { 0 };

    size_t m_num_lines { 0 };

    size_t m_num_columns { 0 };

    size_t m_prompt_lines_at_suggestion_initiation { 0 };

    struct PageRange {

        size_t start;

        size_t end;

    };

    Vector<PageRange> m_pages;

};

}