/*
 * Copyright (c) 2021, Matthew Olsson <mattco@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "OutlineModel.h"
#include <AK/Assertions.h>
#include <LibGUI/ModelRole.h>
#include <LibGfx/Font/FontDatabase.h>
#include <LibGfx/TextAlignment.h>
#include <LibPDF/Document.h>

enum Columns {
    Page,
    Title,
    _Count
};

ErrorOr<NonnullRefPtr<OutlineModel>> OutlineModel::create(NonnullRefPtr<PDF::OutlineDict> const& outline)
{
    auto outline_model = adopt_ref(*new OutlineModel(outline));
    outline_model->m_closed_item_icon.set_bitmap_for_size(16, TRY(Gfx::Bitmap::load_from_file("/res/icons/16x16/book.png"sv)));
    outline_model->m_open_item_icon.set_bitmap_for_size(16, TRY(Gfx::Bitmap::load_from_file("/res/icons/16x16/book-open.png"sv)));
    return outline_model;
}

OutlineModel::OutlineModel(NonnullRefPtr<PDF::OutlineDict> const& outline)
    : m_outline(outline)
{
}

void OutlineModel::set_index_open_state(const GUI::ModelIndex& index, bool is_open)
{
    VERIFY(index.is_valid());
    auto* outline_item = static_cast<PDF::OutlineItem*>(index.internal_data());

    if (is_open) {
        m_open_outline_items.set(outline_item);
    } else {
        m_open_outline_items.remove(outline_item);
    }
}

int OutlineModel::row_count(const GUI::ModelIndex& index) const
{
    if (!index.is_valid())
        return m_outline->children.size();
    auto outline_item = static_cast<PDF::OutlineItem*>(index.internal_data());
    return static_cast<int>(outline_item->children.size());
}

int OutlineModel::tree_column() const
{
    return Columns::Title;
}

int OutlineModel::column_count(const GUI::ModelIndex&) const
{
    return Columns::_Count;
}

PDF::Destination const& OutlineModel::get_destination(GUI::ModelIndex const& index)
{
    auto* outline_item = static_cast<PDF::OutlineItem*>(index.internal_data());
    return outline_item->dest;
}

GUI::Variant OutlineModel::data(const GUI::ModelIndex& index, GUI::ModelRole role) const
{
    VERIFY(index.is_valid());
    auto outline_item = static_cast<PDF::OutlineItem*>(index.internal_data());

    switch (role) {
    case GUI::ModelRole::Display:
        switch (index.column()) {
        case Columns::Title:
            return outline_item->title;
        case Columns::Page: {
            auto maybe_page_number = outline_item->dest.page;
            if (maybe_page_number.has_value()) {
                return maybe_page_number.release_value() + 1;
            }
            return {};
        }
        default:
            VERIFY_NOT_REACHED();
        }

    case GUI::ModelRole::Icon:
        if (m_open_outline_items.contains(outline_item))
            return m_open_item_icon;
        return m_closed_item_icon;
    default:
        return {};

    case GUI::ModelRole::TextAlignment:
        switch (index.column()) {
        case Columns::Title:
            return Gfx::TextAlignment::CenterLeft;
        case Columns::Page:
            return Gfx::TextAlignment::CenterRight;
        default:
            VERIFY_NOT_REACHED();
        }
    }
}

GUI::ModelIndex OutlineModel::parent_index(const GUI::ModelIndex& index) const
{
    if (!index.is_valid())
        return {};

    auto* outline_item = static_cast<PDF::OutlineItem*>(index.internal_data());
    auto& parent = outline_item->parent;

    if (!parent)
        return {};

    Vector<NonnullRefPtr<PDF::OutlineItem>> parent_siblings = (parent->parent ? parent->parent->children : m_outline->children);
    for (size_t i = 0; i < parent_siblings.size(); i++) {
        auto* parent_sibling = parent_siblings[i].ptr();
        if (parent_sibling == parent.ptr())
            return create_index(static_cast<int>(i), index.column(), parent.ptr());
    }

    VERIFY_NOT_REACHED();
}

GUI::ModelIndex OutlineModel::index(int row, int column, const GUI::ModelIndex& parent) const
{
    if (!parent.is_valid())
        return create_index(row, column, m_outline->children[row].ptr());

    auto parent_outline_item = static_cast<PDF::OutlineItem*>(parent.internal_data());
    return create_index(row, column, parent_outline_item->children[row].ptr());
}