#include "ColorPickerPopup.hpp"

#include <algorithm>
#include <cmath>
#include <cstdlib>

#include "Utf8Util.hpp"

namespace jdi
{

	namespace
	{
		const float kPanelWidth = 214.0f;		/**< 面板宽度（逻辑像素）。 */
		const float kPadH = 12.0f;				/**< 面板左右内边距。 */
		const float kPadV = 10.0f;				/**< 面板上下内边距。 */
		const float kTitleHeight = 20.0f;		/**< 标题行高度。 */
		const float kTitleGap = 8.0f;			/**< 标题与滑块区间距。 */
		const float kRowHeight = 26.0f;			/**< 单个滑块行高度。 */
		const float kRowGap = 2.0f;				/**< 滑块行间距。 */
		const float kPreviewGap = 10.0f;		/**< 滑块区与预览区间距。 */
		const float kPreviewHeight = 24.0f;		/**< 预览行高度。 */
		const float kLabelWidth = 16.0f;		/**< 通道标签宽度。 */
		const float kLabelGap = 6.0f;			/**< 标签与滑块间距。 */
		const float kValueWidth = 40.0f;		/**< 数值文本宽度。 */
		const float kTrackHeight = 6.0f;		/**< 滑块轨道高度。 */
		const float kCorner = 6.0f;				/**< 面板圆角半径。 */

		/** @brief 通道显示名称。 */
		const wchar_t* kChannelNames[3] = {L"R", L"G", L"B"};

		/** @brief 通道滑块填充色。 */
		const std::uint32_t kChannelColors[3] = {0xFFDC322Fu, 0xFF859900u, 0xFF268BD2u};

		/**
		 * @brief 绘制水平滑块（与样式区共用同一实现，保证行为一致）。
		 * @param [IN,OUT] g 绘图上下文。
		 * @param [IN] track 轨道矩形。
		 * @param [IN] ratio 当前值比例（0-1）。
		 * @param [IN] fillColor 已填充部分颜色。
		 * @param [IN] hovered 是否处于悬停或拖拽状态。
		 * @param [IN] scale 缩放比例。
		 */
		void DrawChannelSlider(gd::Graphics& g, const gd::RectF& track, double ratio, std::uint32_t fillColor,
		                       bool hovered, float scale)
		{
			UiDrawSlider(g, track, ratio, fillColor, hovered, scale);
		}

		/**
		 * @brief 将 0-1 分量换算为 0-255 整数。
		 * @param [IN] value 分量值。
		 * @return 整数分量。
		 */
		unsigned int ToByte(double value)
		{
			const double scaled = value * 255.0 + 0.5;
			if (scaled < 0.0)
			{
				return 0u;
			}
			if (scaled > 255.0)
			{
				return 255u;
			}
			return static_cast<unsigned int>(scaled);
		}
	}

	ColorPickerPopup::ColorPickerPopup() = default;

	void ColorPickerPopup::Setup(const UiFonts* fonts, const Theme* theme)
	{
		m_fonts = fonts;
		m_theme = theme;
	}

	void ColorPickerPopup::SetScale(float scale)
	{
		m_scale = (scale > 0.1f) ? scale : 1.0f;
	}

	std::uint32_t ColorPickerPopup::CurrentColor() const
	{
		const unsigned int r = ToByte(m_channels[0]);
		const unsigned int g = ToByte(m_channels[1]);
		const unsigned int b = ToByte(m_channels[2]);
		return 0xFF000000u | (r << 16) | (g << 8) | b;
	}

	bool ColorPickerPopup::TakeChanged(std::uint32_t& color)
	{
		if (!m_changed)
		{
			return false;
		}
		m_changed = false;
		color = CurrentColor();
		return true;
	}

	void ColorPickerPopup::BuildLayout(const gd::RectF& bounds, const gd::RectF& anchor)
	{
		const float width = kPanelWidth * m_scale;
		const float height = (kPadV * 2.0f + kTitleHeight + kTitleGap + kRowHeight * 3.0f + kRowGap * 2.0f +
		                      kPreviewGap + kPreviewHeight) *
		                     m_scale;

		const float gap = 4.0f * m_scale;

		// 纵向：优先紧贴触发控件下方展开；空间不足时改到其上方，避免遮挡触发控件本身。
		float top = anchor.Y + anchor.Height + gap;
		if (top + height > bounds.Y + bounds.Height)
		{
			top = anchor.Y - height - gap;
		}
		top = std::max(bounds.Y + 2.0f, std::min(top, bounds.Y + bounds.Height - height - 2.0f));

		// 横向：与触发控件左对齐，越界时再收敛。
		float left = anchor.X;
		if (left + width > bounds.X + bounds.Width)
		{
			left = anchor.X + anchor.Width - width;
		}
		left = std::max(bounds.X + 2.0f, std::min(left, bounds.X + bounds.Width - width - 2.0f));

		m_rect = gd::RectF(left, top, width, height);

		m_titleRect = gd::RectF(left + kPadH * m_scale, top + kPadV * m_scale,
		                        width - kPadH * 2.0f * m_scale, kTitleHeight * m_scale);

		const float trackLeft = left + (kPadH + kLabelWidth + kLabelGap) * m_scale;
		const float trackWidth =
		    std::max(40.0f, width - (trackLeft - left) - (kPadH + kValueWidth) * m_scale);
		const float firstTop = m_titleRect.Y + m_titleRect.Height + kTitleGap * m_scale;

		for (int index = 0; index < 3; ++index)
		{
			const float rowTop = firstTop + static_cast<float>(index) * (kRowHeight + kRowGap) * m_scale;
			m_tracks[static_cast<std::size_t>(index)] =
			    gd::RectF(trackLeft, rowTop + (kRowHeight * m_scale - kTrackHeight * m_scale) * 0.5f,
			              trackWidth, kTrackHeight * m_scale);
			m_values[static_cast<std::size_t>(index)] =
			    gd::RectF(trackLeft + trackWidth + 6.0f * m_scale, rowTop,
			              kValueWidth * m_scale - 6.0f * m_scale, kRowHeight * m_scale);
		}

		const float previewTop = firstTop + 3.0f * (kRowHeight + kRowGap) * m_scale + kPreviewGap * m_scale;
		m_previewRect = gd::RectF(trackLeft, previewTop + 2.0f * m_scale, 52.0f * m_scale, 20.0f * m_scale);
		m_hexRect = gd::RectF(m_previewRect.X + m_previewRect.Width + 8.0f * m_scale, previewTop + 2.0f * m_scale,
		                      96.0f * m_scale, 20.0f * m_scale);
	}

	void ColorPickerPopup::Open(const gd::RectF& bounds, const gd::RectF& anchor, std::uint32_t color)
	{
		m_channels[0] = static_cast<double>((color >> 16) & 0xFFu) / 255.0;
		m_channels[1] = static_cast<double>((color >> 8) & 0xFFu) / 255.0;
		m_channels[2] = static_cast<double>(color & 0xFFu) / 255.0;

		m_open = true;
		m_changed = false;
		m_draggingSlider = -1;
		m_hoverSlider = -1;

		BuildLayout(bounds, anchor);
	}

	void ColorPickerPopup::Close()
	{
		// 收起前先提交正在编辑的取值，避免用户输入被静默丢弃。
		if (m_editField != EditField::NONE)
		{
			EndEdit(true);
		}
		m_open = false;
		m_draggingSlider = -1;
		m_hoverSlider = -1;
	}

	gd::RectF ColorPickerPopup::EditFieldRect() const
	{
		switch (m_editField)
		{
		case EditField::R:
			return m_values[0];
		case EditField::G:
			return m_values[1];
		case EditField::B:
			return m_values[2];
		case EditField::HEX:
			return m_hexRect;
		case EditField::NONE:
		default:
			return gd::RectF();
		}
	}

	bool ColorPickerPopup::BeginEdit(EditField field)
	{
		if (!m_open || field == EditField::NONE)
		{
			return false;
		}
		if (m_editField == field)
		{
			return false;
		}

		switch (field)
		{
		case EditField::R:
		case EditField::G:
		case EditField::B:
		{
			const int index = static_cast<int>(field) - 1;
			m_edit.Begin(std::to_wstring(ToByte(m_channels[static_cast<std::size_t>(index)])), true,
			             EditFilter::BYTE, 3);
			break;
		}
		case EditField::HEX:
		{
			const std::uint32_t color = CurrentColor();
			wchar_t buffer[16];
			swprintf(buffer, sizeof(buffer) / sizeof(buffer[0]), L"%02X%02X%02X", (color >> 16) & 0xFFu,
			         (color >> 8) & 0xFFu, color & 0xFFu);
			m_edit.Begin(std::wstring(buffer), true, EditFilter::HEX, 7);
			break;
		}
		default:
			return false;
		}

		m_draggingSlider = -1;
		m_editField = field;
		return true;
	}

	bool ColorPickerPopup::EndEdit(bool commit)
	{
		if (m_editField == EditField::NONE)
		{
			return false;
		}

		const EditField field = m_editField;
		const std::wstring text = m_edit.Text();
		m_editField = EditField::NONE;
		m_edit.End();

		if (!commit)
		{
			return true;
		}

		const std::wstring trimmed = Trim(text);
		if (field == EditField::HEX)
		{
			// 接受带或不带 '#' 的 6 位十六进制色号。
			std::wstring digits = trimmed;
			if (!digits.empty() && digits.front() == L'#')
			{
				digits.erase(digits.begin());
			}
			if (digits.size() == 6)
			{
				unsigned int value = 0;
				bool valid = true;
				for (const wchar_t c : digits)
				{
					unsigned int digit = 0;
					if (c >= L'0' && c <= L'9')
					{
						digit = static_cast<unsigned int>(c - L'0');
					}
					else if (c >= L'a' && c <= L'f')
					{
						digit = static_cast<unsigned int>(c - L'a') + 10u;
					}
					else if (c >= L'A' && c <= L'F')
					{
						digit = static_cast<unsigned int>(c - L'A') + 10u;
					}
					else
					{
						valid = false;
						break;
					}
					value = (value << 4) | digit;
				}
				if (valid)
				{
					m_channels[0] = static_cast<double>((value >> 16) & 0xFFu) / 255.0;
					m_channels[1] = static_cast<double>((value >> 8) & 0xFFu) / 255.0;
					m_channels[2] = static_cast<double>(value & 0xFFu) / 255.0;
					m_changed = true;
				}
			}
			return true;
		}

		if (trimmed.empty())
		{
			return true;
		}
		wchar_t* stop = nullptr;
		const double parsed = std::wcstod(trimmed.c_str(), &stop);
		if (stop == trimmed.c_str() || parsed != parsed)
		{
			return true;
		}

		double value = parsed;
		if (value < 0.0)
		{
			value = 0.0;
		}
		if (value > 255.0)
		{
			value = 255.0;
		}

		const int index = static_cast<int>(field) - 1;
		if (index >= 0 && index < 3)
		{
			m_channels[static_cast<std::size_t>(index)] = value / 255.0;
			m_changed = true;
		}
		return true;
	}

	bool ColorPickerPopup::OnChar(wchar_t character)
	{
		if (m_editField == EditField::NONE)
		{
			return false;
		}

		// 剪贴板与全选快捷键经 WM_CHAR 送达（Ctrl+C/X/V/A 分别对应 3/24/22/1）。
		switch (character)
		{
		case 0x03: // Ctrl+C
			m_edit.CopyToClipboard(m_owner);
			return false;
		case 0x18: // Ctrl+X
			return m_edit.CutToClipboard(m_owner);
		case 0x16: // Ctrl+V
			return m_edit.PasteFromClipboard(m_owner);
		case 0x01: // Ctrl+A
			m_edit.SelectAll();
			return true;
		default:
			break;
		}

		if (character == L'\r' || character == L'\n')
		{
			return EndEdit(true);
		}
		if (character == L'\b')
		{
			return m_edit.Backspace();
		}
		if (character == 0x7F)
		{
			return m_edit.DeleteForward();
		}
		if (character < 0x20)
		{
			return false;
		}
		return m_edit.Insert(character);
	}

	bool ColorPickerPopup::ContainsPoint(int x, int y) const
	{
		if (!m_open)
		{
			return false;
		}
		return UiPointInRect(m_rect, static_cast<float>(x), static_cast<float>(y));
	}

	HCURSOR ColorPickerPopup::QueryCursor(int x, int y) const
	{
		if (!m_open)
		{
			return nullptr;
		}

		// 拖拽过程中始终保持横向调整光标，避免指针移出轨道后光标跳变。
		if (m_draggingSlider >= 0 || SliderAtPoint(x, y) >= 0)
		{
			return LoadCursorW(nullptr, IDC_SIZEWE);
		}
		return LoadCursorW(nullptr, IDC_ARROW);
	}

	int ColorPickerPopup::SliderAtPoint(int x, int y) const
	{
		if (!m_open)
		{
			return -1;
		}

		const float fx = static_cast<float>(x);
		const float fy = static_cast<float>(y);
		for (int index = 0; index < 3; ++index)
		{
			const gd::RectF& track = m_tracks[static_cast<std::size_t>(index)];
			// 命中范围在纵向适当放宽，便于拖拽。
			const gd::RectF hit(track.X - 4.0f * m_scale, track.Y - 9.0f * m_scale,
			                    track.Width + 8.0f * m_scale, track.Height + 18.0f * m_scale);
			if (UiPointInRect(hit, fx, fy))
			{
				return index;
			}
		}
		return -1;
	}

	void ColorPickerPopup::ApplySlider(int index, float x)
	{
		if (index < 0 || index >= 3)
		{
			return;
		}
		const std::size_t slot = static_cast<std::size_t>(index);
		const double ratio = UiSliderRatioFromX(m_tracks[slot], x);
		if (std::fabs(ratio - m_channels[slot]) < 1.0e-6)
		{
			return;
		}
		m_channels[slot] = ratio;
		m_changed = true;
	}

	bool ColorPickerPopup::OnMouseMove(int x, int y)
	{
		if (!m_open)
		{
			return false;
		}

		if (m_draggingSlider >= 0)
		{
			ApplySlider(m_draggingSlider, static_cast<float>(x));
			return true;
		}

		const int hover = SliderAtPoint(x, y);
		if (hover == m_hoverSlider)
		{
			return false;
		}
		m_hoverSlider = hover;
		return true;
	}

	bool ColorPickerPopup::OnLButtonDown(int x, int y)
	{
		if (!m_open)
		{
			return false;
		}

		if (!ContainsPoint(x, y))
		{
			// 点击面板外部：收起面板（外部点击不再下传，避免误触其他控件）。
			Close();
			return true;
		}

		// 点击当前输入框以外的位置时提交输入。
		if (m_editField != EditField::NONE && !UiPointInRect(EditFieldRect(), static_cast<float>(x),
		                                                     static_cast<float>(y)))
		{
			EndEdit(true);
		}

		// 数值与色号文本优先于滑块：两者几何重叠时要能进入输入状态。
		for (int index = 0; index < 3; ++index)
		{
			if (UiPointInRect(m_values[static_cast<std::size_t>(index)], static_cast<float>(x),
			                  static_cast<float>(y)))
			{
				BeginEdit(static_cast<EditField>(index + 1));
				return true;
			}
		}
		if (UiPointInRect(m_hexRect, static_cast<float>(x), static_cast<float>(y)))
		{
			BeginEdit(EditField::HEX);
			return true;
		}

		m_draggingSlider = SliderAtPoint(x, y);
		if (m_draggingSlider >= 0)
		{
			ApplySlider(m_draggingSlider, static_cast<float>(x));
			return true;
		}
		return true;
	}

	bool ColorPickerPopup::OnLButtonUp()
	{
		if (!m_open || m_draggingSlider < 0)
		{
			return false;
		}
		m_draggingSlider = -1;
		return true;
	}

	bool ColorPickerPopup::OnKeyDown(WPARAM key)
	{
		if (!m_open)
		{
			return false;
		}
		if (m_editField != EditField::NONE)
		{
			const bool shift = (GetKeyState(VK_SHIFT) & 0x8000) != 0;
			const bool control = (GetKeyState(VK_CONTROL) & 0x8000) != 0;

			switch (key)
			{
			case VK_RETURN:
				EndEdit(true);
				return true;
			case VK_ESCAPE:
				EndEdit(false);
				return true;
			case VK_BACK:
				m_edit.Backspace();
				return true;
			case VK_DELETE:
				m_edit.DeleteForward();
				return true;
			case VK_LEFT:
				m_edit.MoveCaret(-1, shift);
				return true;
			case VK_RIGHT:
				m_edit.MoveCaret(1, shift);
				return true;
			case VK_HOME:
				m_edit.MoveHome(shift);
				return true;
			case VK_END:
				m_edit.MoveEnd(shift);
				return true;
			case 'A':
				if (control)
				{
					m_edit.SelectAll();
				}
				return true;
			default:
				break;
			}
			return true;
		}
		if (key == VK_ESCAPE)
		{
			Close();
		}
		return true;
	}

	void ColorPickerPopup::Paint(gd::Graphics& g)
	{
		if (!m_open || m_theme == nullptr || m_fonts == nullptr || m_rect.Width <= 0.0f)
		{
			return;
		}

		// 投影。
		UiFillRoundRect(g, gd::RectF(m_rect.X + 1.0f * m_scale, m_rect.Y + 2.0f * m_scale, m_rect.Width,
		                             m_rect.Height),
		                kCorner * m_scale, 0x14000000u);
		UiFillRoundRect(g, gd::RectF(m_rect.X + 2.0f * m_scale, m_rect.Y + 4.0f * m_scale, m_rect.Width,
		                             m_rect.Height),
		                kCorner * m_scale, 0x10000000u);

		UiFillRoundRect(g, m_rect, kCorner * m_scale, m_theme->cardBg);
		UiDrawRoundRect(g, m_rect, kCorner * m_scale, m_theme->borderStrong, 1.0f);

		UiText(g, L"自定义颜色", m_fonts->uiSmallBold, m_titleRect, m_theme->textMuted, TextAlign::LEFT);

		for (int index = 0; index < 3; ++index)
		{
			const std::size_t slot = static_cast<std::size_t>(index);
			const gd::RectF& track = m_tracks[slot];

			const gd::RectF labelRect(m_rect.X + kPadH * m_scale, track.Y - 9.0f * m_scale,
			                          kLabelWidth * m_scale, kRowHeight * m_scale);
			UiText(g, kChannelNames[index], m_fonts->uiSmall, labelRect, m_theme->textMuted, TextAlign::LEFT);

			const bool active = (m_draggingSlider == index) || (m_hoverSlider == index);
			DrawChannelSlider(g, track, m_channels[slot], kChannelColors[index], active, m_scale);

			if (m_editField == static_cast<EditField>(index + 1))
			{
				UiDrawEditField(g, m_values[slot], m_edit, m_fonts->monoSmall, m_scale);
			}
			else
			{
				UiText(g, std::to_wstring(ToByte(m_channels[slot])), m_fonts->monoSmall, m_values[slot],
				       m_theme->text, TextAlign::RIGHT);
			}
		}

		// 预览与十六进制值。
		const std::uint32_t color = CurrentColor();
		UiFillRoundRect(g, m_previewRect, 3.0f * m_scale, color);
		UiDrawRoundRect(g, m_previewRect, 3.0f * m_scale, m_theme->borderStrong, 1.0f);

		if (m_editField == EditField::HEX)
		{
			UiDrawEditField(g, m_hexRect, m_edit, m_fonts->monoSmall, m_scale);
		}
		else
		{
			wchar_t buffer[16];
			swprintf(buffer, sizeof(buffer) / sizeof(buffer[0]), L"#%02X%02X%02X", (color >> 16) & 0xFFu,
			         (color >> 8) & 0xFFu, color & 0xFFu);
			UiText(g, std::wstring(buffer), m_fonts->monoSmall, m_hexRect, m_theme->text, TextAlign::LEFT);
		}
	}

} // namespace jdi