#include "specter/ScrollView.hpp"

#include <algorithm>

#include "specter/Button.hpp"
#include "specter/IViewManager.hpp"
#include "specter/RootView.hpp"
#include "specter/ViewResources.hpp"

namespace specter {
#define MAX_SCROLL_SPEED 100

ScrollView::ScrollView(ViewResources& res, View& parentView, Style style)
: View(res, parentView), m_style(style), m_sideButtonBind(*this, rootView().viewManager()) {
  commitResources(res, [&](boo::IGraphicsDataFactory::Context& ctx) -> bool {
    buildResources(ctx, res);
    m_vertsBinding.init(ctx, res, 4, m_viewVertBlockBuf);
    return true;
  });

  if (style == Style::SideButtons) {
    m_sideButtons[0].m_view.reset(new Button(res, *this, &m_sideButtonBind, "<"));
    m_sideButtons[1].m_view.reset(new Button(res, *this, &m_sideButtonBind, ">"));
  }
}

ScrollView::SideButtonBinding::SideButtonBinding(ScrollView& sv, IViewManager& vm)
: m_sv(sv), m_leftName(vm.translate<locale::scroll_left>()), m_rightName(vm.translate<locale::scroll_right>()) {}

std::string_view ScrollView::SideButtonBinding::name(const Control* control) const {
  return (control == reinterpret_cast<Control*>(m_sv.m_sideButtons[0].m_view.get())) ? m_leftName.c_str()
                                                                                     : m_rightName.c_str();
}

void ScrollView::SideButtonBinding::down(const Button* button, [[maybe_unused]] const boo::SWindowCoord& coord) {
  if (button == m_sv.m_sideButtons[0].m_view.get()) {
    m_sv.m_sideButtonState = SideButtonState::ScrollRight;
  } else {
    m_sv.m_sideButtonState = SideButtonState::ScrollLeft;
  }
}

void ScrollView::SideButtonBinding::up([[maybe_unused]] const Button* button,
                                       [[maybe_unused]] const boo::SWindowCoord& coord) {
  m_sv.m_sideButtonState = SideButtonState::None;
}

bool ScrollView::_scroll(const boo::SScrollDelta& scroll) {
  if (m_contentView.m_view) {
    float ratioX = subRect().size[0] / float(m_contentView.m_view->nominalWidth());
    float ratioY = subRect().size[1] / float(m_contentView.m_view->nominalHeight());

    float pf = rootView().viewRes().pixelFactor();
    double mult = 20.0 * pf;
    if (scroll.isFine)
      mult = 1.0 * pf;

    bool ret = false;

    if (ratioX >= 1.f) {
      m_scroll[0] = 0;
      m_targetScroll[0] = 0;
      m_drawSideButtons = false;
      ret = true;
    } else {
      m_drawSideButtons = true;
      m_targetScroll[0] += scroll.delta[0] * mult;
      m_targetScroll[0] = std::min(m_targetScroll[0], 0);
      int scrollWidth = m_contentView.m_view->nominalWidth() - scrollAreaWidth();
      m_targetScroll[0] = std::max(m_targetScroll[0], -scrollWidth);
    }

    if (ratioY >= 1.f) {
      m_scroll[1] = 0;
      m_targetScroll[1] = 0;
      ret = true;
    } else {
      m_targetScroll[1] -= scroll.delta[1] * mult;
      m_targetScroll[1] = std::max(m_targetScroll[1], 0);
      int scrollHeight = m_contentView.m_view->nominalHeight() - subRect().size[1];
      m_targetScroll[1] = std::min(m_targetScroll[1], scrollHeight);
    }

    if (scroll.isFine) {
      m_scroll[0] = m_targetScroll[0];
      m_scroll[1] = m_targetScroll[1];
      ret = true;
    }

    return ret;
  } else {
    m_scroll[0] = 0;
    m_scroll[1] = 0;
    m_targetScroll[0] = 0;
    m_targetScroll[1] = 0;
    m_drawSideButtons = false;
    return true;
  }
  return false;
}

int ScrollView::scrollAreaWidth() const {
  int ret = subRect().size[0];
  if (m_style == Style::SideButtons && m_drawSideButtons) {
    ret -= m_sideButtons[0].m_view->nominalWidth();
    ret -= m_sideButtons[1].m_view->nominalWidth();
  }
  return std::max(0, ret);
}

void ScrollView::mouseDown(const boo::SWindowCoord& coord, boo::EMouseButton button, boo::EModifierKey mod) {
  if (m_style == Style::SideButtons && m_drawSideButtons) {
    if (m_sideButtons[0].mouseDown(coord, button, mod) || m_sideButtons[1].mouseDown(coord, button, mod))
      return;
  }
  m_contentView.mouseDown(coord, button, mod);
}

void ScrollView::mouseUp(const boo::SWindowCoord& coord, boo::EMouseButton button, boo::EModifierKey mod) {
  if (m_style == Style::SideButtons) {
    m_sideButtons[0].mouseUp(coord, button, mod);
    m_sideButtons[1].mouseUp(coord, button, mod);
  }
  m_contentView.mouseUp(coord, button, mod);
}

void ScrollView::mouseMove(const boo::SWindowCoord& coord) {
  if (m_style == Style::SideButtons && m_drawSideButtons) {
    m_sideButtons[0].mouseMove(coord);
    m_sideButtons[1].mouseMove(coord);
  }
  m_contentView.mouseMove(coord);
}

void ScrollView::mouseEnter(const boo::SWindowCoord& coord) {
  if (m_style == Style::SideButtons && m_drawSideButtons) {
    m_sideButtons[0].mouseEnter(coord);
    m_sideButtons[1].mouseEnter(coord);
  }
  m_contentView.mouseEnter(coord);
}

void ScrollView::mouseLeave(const boo::SWindowCoord& coord) {
  if (m_style == Style::SideButtons) {
    m_sideButtons[0].mouseLeave(coord);
    m_sideButtons[1].mouseLeave(coord);
  }
  m_contentView.mouseLeave(coord);
}

void ScrollView::scroll(const boo::SWindowCoord& coord, const boo::SScrollDelta& scroll) {
  if (!scroll.isAccelerated) {
    boo::SScrollDelta newScroll = scroll;
    m_consecutiveScroll[m_consecutiveIdx][0] += scroll.delta[0];
    m_consecutiveScroll[m_consecutiveIdx][1] += scroll.delta[1];
    newScroll.delta[0] = 0;
    newScroll.delta[1] = 0;
    for (size_t i = 0; i < 16; ++i) {
      newScroll.delta[0] += m_consecutiveScroll[i][0];
      newScroll.delta[1] += m_consecutiveScroll[i][1];
    }
    if (_scroll(newScroll))
      updateSize();
    return;
  }
  if (_scroll(scroll))
    updateSize();
}

void ScrollView::setMultiplyColor(const zeus::CColor& color) {
  View::setMultiplyColor(color);
  if (m_style == Style::SideButtons) {
    m_sideButtons[0].m_view->setMultiplyColor(color);
    m_sideButtons[1].m_view->setMultiplyColor(color);
  }
  if (m_contentView.m_view)
    m_contentView.m_view->setMultiplyColor(color);
}

void ScrollView::think() {
  m_consecutiveIdx = (m_consecutiveIdx + 1) % 16;
  m_consecutiveScroll[m_consecutiveIdx][0] = 0.0;
  m_consecutiveScroll[m_consecutiveIdx][1] = 0.0;

  if (m_sideButtonState != SideButtonState::None) {
    if (m_sideButtonState == SideButtonState::ScrollLeft)
      m_targetScroll[0] -= 3;
    else if (m_sideButtonState == SideButtonState::ScrollRight)
      m_targetScroll[0] += 3;
    m_targetScroll[0] = std::min(m_targetScroll[0], 0);
    int scrollWidth = m_contentView.m_view->nominalWidth() - scrollAreaWidth();
    m_targetScroll[0] = std::max(m_targetScroll[0], -scrollWidth);
  }

  bool update = false;
  float pf = rootView().viewRes().pixelFactor();

  int xSpeed = std::max(1, std::min(abs(m_targetScroll[0] - m_scroll[0]) / int(5 * pf), int(pf * MAX_SCROLL_SPEED)));
  if (m_scroll[0] < m_targetScroll[0]) {
    m_scroll[0] += xSpeed;
    update = true;
  } else if (m_scroll[0] > m_targetScroll[0]) {
    m_scroll[0] -= xSpeed;
    update = true;
  }

  int ySpeed = std::max(1, std::min(abs(m_targetScroll[1] - m_scroll[1]) / int(5 * pf), int(pf * MAX_SCROLL_SPEED)));
  if (m_scroll[1] < m_targetScroll[1]) {
    m_scroll[1] += ySpeed;
    update = true;
  } else if (m_scroll[1] > m_targetScroll[1]) {
    m_scroll[1] -= ySpeed;
    update = true;
  }

  if (update)
    updateSize();
}

void ScrollView::resized(const boo::SWindowRect& root, const boo::SWindowRect& sub) {
  View::resized(root, sub);
  _scroll({});
  if (m_contentView.m_view) {
    boo::SWindowRect cRect = sub;
    cRect.location[0] += m_scroll[0];
    cRect.location[1] += sub.size[1] - m_contentView.m_view->nominalHeight() + m_scroll[1];
    cRect.size[0] = m_contentView.m_view->nominalWidth();
    cRect.size[1] = m_contentView.m_view->nominalHeight();
    m_contentView.m_scissorRect = sub;
    if (m_style == Style::SideButtons && m_drawSideButtons) {
      int width0 = m_sideButtons[0].m_view->nominalWidth() + 2;
      int width1 = m_sideButtons[1].m_view->nominalWidth();
      cRect.location[0] += width0;
      cRect.size[0] -= (width0 + width1);

      m_contentView.m_scissorRect.location[0] += width0;
      m_contentView.m_scissorRect.size[0] -= (width0 + width1);
    }
    m_contentView.m_view->resized(root, cRect, m_contentView.m_scissorRect);

    if (m_style == Style::ThinIndicator) {
      float ratio = sub.size[1] / float(cRect.size[1]);
      m_drawInd = ratio < 1.f;
      if (m_drawInd) {
        float pf = rootView().viewRes().pixelFactor();
        int barHeight = sub.size[1] * ratio;
        int scrollHeight = sub.size[1] - barHeight;
        float prog = m_scroll[1] / float(cRect.size[1] - sub.size[1]);
        int x = sub.size[0];
        int y = sub.size[1] - scrollHeight * prog;
        m_verts[0].m_pos.assign(x, y, 0);
        m_verts[1].m_pos.assign(x, y - barHeight, 0);
        m_verts[2].m_pos.assign(x + 2 * pf, y, 0);
        m_verts[3].m_pos.assign(x + 2 * pf, y - barHeight, 0);
        const zeus::CColor& color = rootView().themeData().scrollIndicator();
        for (int i = 0; i < 4; ++i)
          m_verts[i].m_color = color;
        m_vertsBinding.load<decltype(m_verts)>(m_verts);
      }
    } else if (m_style == Style::SideButtons && m_drawSideButtons) {
      boo::SWindowRect bRect = sub;
      bRect.size[0] = m_sideButtons[0].m_view->nominalWidth();
      bRect.size[1] = m_sideButtons[0].m_view->nominalHeight();
      m_sideButtons[0].m_view->resized(root, bRect);

      bRect.size[0] = m_sideButtons[1].m_view->nominalWidth();
      bRect.size[1] = m_sideButtons[1].m_view->nominalHeight();
      bRect.location[0] += sub.size[0] - bRect.size[0];
      m_sideButtons[1].m_view->resized(root, bRect);
    }
  }
}

void ScrollView::draw(boo::IGraphicsCommandQueue* gfxQ) {
  if (m_contentView.m_view) {
    m_contentView.m_view->draw(gfxQ);

    if (m_style == Style::ThinIndicator && m_drawInd) {
      gfxQ->setShaderDataBinding(m_vertsBinding);
      gfxQ->draw(0, 4);
    } else if (m_style == Style::SideButtons && m_drawSideButtons) {
      m_sideButtons[0].m_view->draw(gfxQ);
      m_sideButtons[1].m_view->draw(gfxQ);
    }
  }
}

} // namespace specter