#include "text_box.hpp"

#include <cwctype>
#include <cassert>

#include "graph/graph.hpp"
#include "exception.hpp"
#include "ui/ui_manager.hpp"

namespace cru::ui::controls
{
    TextBox::TextBox() : TextControl(
        UiManager::GetInstance()->GetPredefineResources()->text_box_text_format,
        UiManager::GetInstance()->GetPredefineResources()->text_box_text_brush
    )
    {
        SetSelectable(true);

        caret_brush_ = UiManager::GetInstance()->GetPredefineResources()->text_box_caret_brush;

        GetBorderProperty() = UiManager::GetInstance()->GetPredefineResources()->text_box_border;
        SetBordered(true);

        draw_content_event.AddHandler([this](events::DrawEventArgs& args)
        {
            const auto device_context = args.GetDeviceContext();
            if (is_caret_show_)
            {
                const auto caret_half_width = UiManager::GetInstance()->GetCaretInfo().half_caret_width;
                FLOAT x, y;
                DWRITE_HIT_TEST_METRICS metrics{};
                ThrowIfFailed(text_layout_->HitTestTextPosition(caret_position_, FALSE, &x, &y, &metrics));
                device_context->FillRectangle(D2D1::RectF(metrics.left - caret_half_width, metrics.top, metrics.left + caret_half_width, metrics.top + metrics.height), caret_brush_.Get());
            }
        });

        get_focus_event.direct.AddHandler([this](events::FocusChangeEventArgs& args)
        {
            assert(!caret_timer_.has_value());
            is_caret_show_ = true;
            caret_timer_ = SetInterval(UiManager::GetInstance()->GetCaretInfo().caret_blink_duration, [this]
            {
                is_caret_show_ = !is_caret_show_;
                InvalidateDraw();
            });
        });

        lose_focus_event.direct.AddHandler([this](events::FocusChangeEventArgs& args)
        {
            assert(caret_timer_.has_value());
            caret_timer_->Cancel();
            caret_timer_ = std::nullopt;
            is_caret_show_ = false;
        });

        key_down_event.bubble.AddHandler([this](events::KeyEventArgs& args)
        {
            if (args.GetVirtualCode() == VK_LEFT && caret_position_ > 0)
            {
                if (IsKeyDown(VK_SHIFT))
                {
                    if (GetCaretSelectionSide())
                        ShiftLeftSelectionRange(-1);
                    else
                        ShiftRightSelectionRange(-1);
                }
                else
                {
                    const auto selection = GetSelectedRange();
                    if (selection.has_value())
                    {
                        ClearSelection();
                        caret_position_ = selection.value().position;
                    }
                    else
                        caret_position_--;
                }
                InvalidateDraw();
            }

            if (args.GetVirtualCode() == VK_RIGHT && caret_position_ < GetText().size())
            {
                if (IsKeyDown(VK_SHIFT))
                {
                    if (GetCaretSelectionSide())
                        ShiftLeftSelectionRange(1);
                    else
                        ShiftRightSelectionRange(1);
                }
                else
                {
                    const auto selection = GetSelectedRange();
                    if (selection.has_value())
                    {
                        ClearSelection();
                        caret_position_ = selection.value().position + selection.value().count;
                    }
                    else
                        caret_position_++;
                }
            }
        });

        char_event.bubble.AddHandler([this](events::CharEventArgs& args)
        {
            if (args.GetChar() == L'\b')
            {
                if (GetSelectedRange().has_value())
                {
                    const auto selection_range = GetSelectedRange().value();
                    auto text = GetText();
                    text.erase(text.cbegin() + selection_range.position, text.cbegin() + selection_range.position + selection_range.count);
                    SetText(text);
                    caret_position_ = selection_range.position;
                    ClearSelection();
                }
                else
                {
                    if (caret_position_ > 0)
                    {
                        auto text = GetText();
                        if (!text.empty())
                        {
                            const auto position = --caret_position_;
                            text.erase(text.cbegin() + position);
                            SetText(text);
                        }
                    }
                }
                return;
            }

            if (std::iswprint(args.GetChar()))
            {
                if (GetSelectedRange().has_value())
                {
                    const auto selection_range = GetSelectedRange().value();
                    auto text = GetText();
                    text.erase(selection_range.position, selection_range.count);
                    text.insert(text.cbegin() + selection_range.position, args.GetChar());
                    SetText(text);
                    caret_position_ = selection_range.position + 1;
                    ClearSelection();
                }
                else
                {
                    ClearSelection();
                    const auto position = caret_position_++;
                    auto text = GetText();
                    text.insert(text.cbegin() + position, { args.GetChar() });
                    SetText(text);
                }
            }
        });
    }

    TextBox::~TextBox() = default;

    StringView TextBox::GetControlType() const
    {
        return control_type;
    }

    void TextBox::RequestChangeCaretPosition(const unsigned position)
    {
        caret_position_ = position;
        InvalidateDraw();
    }

    bool TextBox::GetCaretSelectionSide() const
    {
        const auto selection = TextRange::ToTwoSides(GetSelectedRange(), caret_position_);
        if (selection.first == caret_position_)
            return true;
        if (selection.second == caret_position_)
            return false;
        assert(false);
        return true;
    }

    void TextBox::ShiftLeftSelectionRange(const int count)
    {
        const auto selection_range_side = TextRange::ToTwoSides(GetSelectedRange(), caret_position_);
        int new_left = selection_range_side.first + count;
        new_left = new_left < 0 ? 0 : new_left; // at least 0
        caret_position_ = new_left;
        SetSelectedRange(TextRange::FromTwoSides(static_cast<unsigned>(new_left), selection_range_side.second));
    }

    void TextBox::ShiftRightSelectionRange(const int count)
    {
        const auto selection_range_side = TextRange::ToTwoSides(GetSelectedRange(), caret_position_);
        int new_right = selection_range_side.second + count;
        new_right = new_right < 0 ? 0 : new_right; // at least 0
        caret_position_ = new_right;
        SetSelectedRange(TextRange::FromTwoSides(selection_range_side.first, static_cast<unsigned>(new_right)));
    }
}