/*
 * Copyright 2016 - 2025 Gary Talent (gary@drinkingtea.net). All rights reserved.
 */

#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <lodepng.h>
#if TURBINE_USE_IMGUI
#include <imgui_impl_glfw.h>
#include <imgui_impl_opengl3.h>
#endif

#include "config.hpp"

#include <ox/std/span.hpp>

#include "context.hpp"

namespace turbine {

namespace gl {

void addDrawer(Context &ctx, Drawer *cd) noexcept {
	ctx.drawers.emplace_back(cd);
}

void removeDrawer(Context &ctx, Drawer *cd) noexcept {
	for (auto i = 0u; i < ctx.drawers.size(); ++i) {
		if (ctx.drawers[i] == cd) {
			std::ignore = ctx.drawers.erase(i);
			break;
		}
	}
}

}

static void handleGlfwError(int err, char const*desc) noexcept {
	oxErrf("GLFW error ({}): {}\n", err, desc);
}

static auto setKeyDownStatus(Context &ctx, Key key, bool down) noexcept {
	ctx.keysDown &= ~(1llu << static_cast<int>(key));
	ctx.keysDown |= static_cast<uint64_t>(down) << static_cast<int>(key);
}

static void handleKeyPress(Context &ctx, int key, bool down) noexcept {
	static constexpr auto keyMap = [] {
		ox::Array<Key, GLFW_KEY_LAST> map = {};
		for (auto i = 0u; i < 26; ++i) {
			map[GLFW_KEY_A + i] = static_cast<Key>(static_cast<unsigned>(Key::Alpha_A) + i);
		}
		for (auto i = 0u; i < 10; ++i) {
			map[GLFW_KEY_0 + i] = static_cast<Key>(static_cast<unsigned>(Key::Num_0) + i);
		}
		map[GLFW_KEY_LEFT_ALT]      = Key::Mod_Alt;
		map[GLFW_KEY_RIGHT_ALT]     = Key::Mod_Alt;
		map[GLFW_KEY_LEFT_CONTROL]  = Key::Mod_Ctrl;
		map[GLFW_KEY_RIGHT_CONTROL] = Key::Mod_Ctrl;
		map[GLFW_KEY_LEFT_SUPER]    = Key::Mod_Super;
		map[GLFW_KEY_RIGHT_SUPER]   = Key::Mod_Super;
		map[GLFW_KEY_LEFT_SHIFT]    = Key::Mod_Shift;
		map[GLFW_KEY_RIGHT_SHIFT]   = Key::Mod_Shift;
		map[GLFW_KEY_ESCAPE]        = Key::Escape;
		return map;
	}();
	auto const eventHandler = keyEventHandler(ctx);
	auto const keyIdx = static_cast<std::size_t>(key);
	if (keyIdx < keyMap.size()) {
		auto const k = keyMap[keyIdx];
		setKeyDownStatus(ctx, k, down);
		if (eventHandler) {
			eventHandler(ctx, k, down);
		}
	}
}

static void handleGlfwCursorPosEvent(GLFWwindow*, double, double) noexcept {
}

static void handleGlfwMouseButtonEvent(GLFWwindow *window, int, int, int) noexcept {
	auto &ctx = *static_cast<Context*>(glfwGetWindowUserPointer(window));
	ctx.mandatoryRefreshPeriodEnd = ticksMs(ctx) + config::MandatoryRefreshPeriod;
}

static void handleGlfwKeyEvent(GLFWwindow *window, int key, int, int action, int) noexcept {
	auto &ctx = *static_cast<Context*>(glfwGetWindowUserPointer(window));
	ctx.mandatoryRefreshPeriodEnd = ticksMs(ctx) + config::MandatoryRefreshPeriod;
	if (action == GLFW_PRESS) {
		handleKeyPress(ctx, key, true);
	} else if (action == GLFW_RELEASE) {
		handleKeyPress(ctx, key, false);
	}
}

#if TURBINE_USE_IMGUI
static void themeImgui() noexcept {
	// Dark Ruda style by Raikiri from ImThemes
	auto &style = ImGui::GetStyle();
	style.Alpha = 1.0;
	style.DisabledAlpha = 0.6000000238418579;
	style.WindowPadding = ImVec2(8.0, 8.0);
	style.WindowRounding = 0.0;
	style.WindowBorderSize = 1.0;
	style.WindowMinSize = ImVec2(32.0, 32.0);
	style.WindowTitleAlign = ImVec2(0.0, 0.5);
	style.WindowMenuButtonPosition = ImGuiDir_Left;
	style.ChildRounding = 0.0;
	style.ChildBorderSize = 1.0;
	style.PopupRounding = 0.0;
	style.PopupBorderSize = 1.0;
	style.FramePadding = ImVec2(4.0, 3.0);
	// custom value
	style.FrameRounding = 3.0;
	style.FrameBorderSize = 0.0;
	style.ItemSpacing = ImVec2(8.0, 4.0);
	style.ItemInnerSpacing = ImVec2(4.0, 4.0);
	style.CellPadding = ImVec2(4.0, 2.0);
	style.IndentSpacing = 21.0;
	style.ColumnsMinSpacing = 6.0;
	style.ScrollbarSize = 14.0;
	style.ScrollbarRounding = 9.0;
	style.GrabMinSize = 10.0;
	style.GrabRounding = 4.0;
	style.TabRounding = 4.0;
	style.TabBorderSize = 0.0;
	style.TabMinWidthForCloseButton = 0.0;
	style.ColorButtonPosition = ImGuiDir_Right;
	style.ButtonTextAlign = ImVec2(0.5, 0.5);
	style.SelectableTextAlign = ImVec2(0.0, 0.0);
	// colors
	constexpr auto imVec4 = [](double r, double g, double b, double a) {
		return ImVec4(
				static_cast<float>(r),
				static_cast<float>(g),
				static_cast<float>(b),
				static_cast<float>(a));
	};
	auto colors = ox::Span(style.Colors);
	colors[ImGuiCol_Text] = imVec4(0.9490196108818054, 0.95686274766922, 0.9764705896377563, 1.0);
	colors[ImGuiCol_TextDisabled] = imVec4(0.3568627536296844, 0.4196078479290009, 0.4666666686534882, 1.0);
	colors[ImGuiCol_WindowBg] = imVec4(0.1098039224743843, 0.1490196138620377, 0.168627455830574, 1.0);
	colors[ImGuiCol_ChildBg] = imVec4(0.1490196138620377, 0.1764705926179886, 0.2196078449487686, 1.0);
	colors[ImGuiCol_PopupBg] = imVec4(0.0784313753247261, 0.0784313753247261, 0.0784313753247261, 0.9399999976158142);
	colors[ImGuiCol_Border] = imVec4(0.0784313753247261, 0.09803921729326248, 0.1176470592617989, 1.0);
	colors[ImGuiCol_BorderShadow] = imVec4(0.0, 0.0, 0.0, 0.0);
	colors[ImGuiCol_FrameBg] = imVec4(0.2000000029802322, 0.2470588237047195, 0.2862745225429535, 1.0);
	colors[ImGuiCol_FrameBgHovered] = imVec4(0.1176470592617989, 0.2000000029802322, 0.2784313857555389, 1.0);
	colors[ImGuiCol_FrameBgActive] = imVec4(0.08627451211214066, 0.1176470592617989, 0.1372549086809158, 1.0);
	colors[ImGuiCol_TitleBg] = imVec4(0.08627451211214066, 0.1176470592617989, 0.1372549086809158, 0.6499999761581421);
	colors[ImGuiCol_TitleBgActive] = imVec4(0.0784313753247261, 0.09803921729326248, 0.1176470592617989, 1.0);
	colors[ImGuiCol_TitleBgCollapsed] = imVec4(0.0, 0.0, 0.0, 0.5099999904632568);
	colors[ImGuiCol_MenuBarBg] = imVec4(0.1490196138620377, 0.1764705926179886, 0.2196078449487686, 1.0);
	colors[ImGuiCol_ScrollbarBg] = imVec4(0.01960784383118153, 0.01960784383118153, 0.01960784383118153, 0.3899999856948853);
	colors[ImGuiCol_ScrollbarGrab] = imVec4(0.2000000029802322, 0.2470588237047195, 0.2862745225429535, 1.0);
	colors[ImGuiCol_ScrollbarGrabHovered] = imVec4(0.1764705926179886, 0.2196078449487686, 0.2470588237047195, 1.0);
	colors[ImGuiCol_ScrollbarGrabActive] = imVec4(0.08627451211214066, 0.2078431397676468, 0.3098039329051971, 1.0);
	colors[ImGuiCol_CheckMark] = imVec4(0.2784313857555389, 0.5568627715110779, 1.0, 1.0);
	colors[ImGuiCol_SliderGrab] = imVec4(0.2784313857555389, 0.5568627715110779, 1.0, 1.0);
	colors[ImGuiCol_SliderGrabActive] = imVec4(0.3686274588108063, 0.6078431606292725, 1.0, 1.0);
	colors[ImGuiCol_Button] = imVec4(0.2000000029802322, 0.2470588237047195, 0.2862745225429535, 1.0);
	colors[ImGuiCol_ButtonHovered] = imVec4(0.2784313857555389, 0.5568627715110779, 1.0, 1.0);
	colors[ImGuiCol_ButtonActive] = imVec4(0.05882352963089943, 0.529411792755127, 0.9764705896377563, 1.0);
	// custom value
	colors[ImGuiCol_Header] = imVec4(0.4000000029802322, 0.4470588237047195, 0.4862745225429535, 0.550000011920929);
	colors[ImGuiCol_HeaderHovered] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 0.800000011920929);
	colors[ImGuiCol_HeaderActive] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 1.0);
	colors[ImGuiCol_Separator] = imVec4(0.2000000029802322, 0.2470588237047195, 0.2862745225429535, 1.0);
	colors[ImGuiCol_SeparatorHovered] = imVec4(0.09803921729326248, 0.4000000059604645, 0.7490196228027344, 0.7799999713897705);
	colors[ImGuiCol_SeparatorActive] = imVec4(0.09803921729326248, 0.4000000059604645, 0.7490196228027344, 1.0);
	colors[ImGuiCol_ResizeGrip] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 0.25);
	colors[ImGuiCol_ResizeGripHovered] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 0.6700000166893005);
	colors[ImGuiCol_ResizeGripActive] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 0.949999988079071);
	colors[ImGuiCol_Tab] = imVec4(0.1098039224743843, 0.1490196138620377, 0.168627455830574, 1.0);
	colors[ImGuiCol_TabHovered] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 0.800000011920929);
	colors[ImGuiCol_TabActive] = imVec4(0.2000000029802322, 0.2470588237047195, 0.2862745225429535, 1.0);
	colors[ImGuiCol_TabUnfocused] = imVec4(0.1098039224743843, 0.1490196138620377, 0.168627455830574, 1.0);
	colors[ImGuiCol_TabUnfocusedActive] = imVec4(0.1098039224743843, 0.1490196138620377, 0.168627455830574, 1.0);
	colors[ImGuiCol_PlotLines] = imVec4(0.6078431606292725, 0.6078431606292725, 0.6078431606292725, 1.0);
	colors[ImGuiCol_PlotLinesHovered] = imVec4(1.0, 0.4274509847164154, 0.3490196168422699, 1.0);
	colors[ImGuiCol_PlotHistogram] = imVec4(0.8980392217636108, 0.6980392336845398, 0.0, 1.0);
	colors[ImGuiCol_PlotHistogramHovered] = imVec4(1.0, 0.6000000238418579, 0.0, 1.0);
	colors[ImGuiCol_TableHeaderBg] = imVec4(0.1882352977991104, 0.1882352977991104, 0.2000000029802322, 1.0);
	colors[ImGuiCol_TableBorderStrong] = imVec4(0.3098039329051971, 0.3098039329051971, 0.3490196168422699, 1.0);
	colors[ImGuiCol_TableBorderLight] = imVec4(0.2274509817361832, 0.2274509817361832, 0.2470588237047195, 1.0);
	colors[ImGuiCol_TableRowBg] = imVec4(0.0, 0.0, 0.0, 0.0);
	colors[ImGuiCol_TableRowBgAlt] = imVec4(1.0, 1.0, 1.0, 0.05999999865889549);
	colors[ImGuiCol_TextSelectedBg] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 0.3499999940395355);
	colors[ImGuiCol_DragDropTarget] = imVec4(1.0, 1.0, 0.0, 0.8999999761581421);
	colors[ImGuiCol_NavHighlight] = imVec4(0.2588235437870026, 0.5882353186607361, 0.9764705896377563, 1.0);
	colors[ImGuiCol_NavWindowingHighlight] = imVec4(1.0, 1.0, 1.0, 0.699999988079071);
	colors[ImGuiCol_NavWindowingDimBg] = imVec4(0.800000011920929, 0.800000011920929, 0.800000011920929, 0.2000000029802322);
	colors[ImGuiCol_ModalWindowDimBg] = imVec4(0.800000011920929, 0.800000011920929, 0.800000011920929, 0.3499999940395355);
}
#endif

ox::Error initGfx(Context &ctx) noexcept {
	glfwSetErrorCallback(handleGlfwError);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
	glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);
	glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
	constexpr auto Scale = 5;
	ctx.window = glfwCreateWindow(240 * Scale, 160 * Scale, ctx.keelCtx.appName.c_str(), nullptr, nullptr);
	//ctx.window = glfwCreateWindow(876, 743, ctx.keelCtx.appName.c_str(), nullptr, nullptr);
	if (ctx.window == nullptr) {
		return ox::Error(1, "Could not open GLFW window");
	}
	glfwSetCursorPosCallback(ctx.window, handleGlfwCursorPosEvent);
	glfwSetMouseButtonCallback(ctx.window, handleGlfwMouseButtonEvent);
	glfwSetKeyCallback(ctx.window, handleGlfwKeyEvent);
	glfwSetWindowUserPointer(ctx.window, &ctx);
	glfwMakeContextCurrent(ctx.window);
	if (!gladLoadGLES2Loader(reinterpret_cast<GLADloadproc>(glfwGetProcAddress))) {
		return ox::Error(2, "Could not init Glad");
	}
#if TURBINE_USE_IMGUI
	IMGUI_CHECKVERSION();
	ImGui::CreateContext();
	auto &io = ImGui::GetIO();
	io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
	//io.MouseDrawCursor = true;
	ImGui_ImplGlfw_InitForOpenGL(ctx.window, true);
	ImGui_ImplOpenGL3_Init();
	io.IniFilename = nullptr;
	themeImgui();
#endif
	return {};
}

struct IconData {
	std::vector<uint8_t> pixels;
	int w{}, h{};
};

[[nodiscard]]
static ox::Result<IconData> toGlfwImgPixels(ox::SpanView<uint8_t> const &iconPng) noexcept {
	ox::Result<IconData> out;
	unsigned w{}, h{};
	if (lodepng::decode(out.value.pixels, w, h, iconPng.data(), iconPng.size())) {
		return ox::Error{1, "unable to decode window icon PNG data"};
	}
	out.value.w = static_cast<int>(w);
	out.value.h = static_cast<int>(h);
	return out;
}

ox::Error setWindowIcon(Context &ctx, ox::SpanView<ox::SpanView<uint8_t>> const &iconPngs) noexcept {
	ox::Vector<IconData, 8> src;
	ox::Vector<GLFWimage, 8> imgs;
	for (auto const &iconPng : iconPngs) {
		OX_RETURN_ERROR(toGlfwImgPixels(iconPng).moveTo(src.emplace_back()));
		auto &icon = *src.back().unwrap();
		imgs.emplace_back(GLFWimage{
			.width = icon.w,
			.height = icon.h,
			.pixels = icon.pixels.data(),
		});
	}
	glfwSetWindowIcon(ctx.window, static_cast<int>(imgs.size()), imgs.data());
	return {};
}

void setWindowTitle(Context &ctx, ox::StringViewCR title) noexcept {
	auto cstr = ox_malloca(title.bytes() + 1, char);
	ox::strncpy(cstr.get(), title.data(), title.bytes());
	glfwSetWindowTitle(ctx.window, cstr.get());
}

void focusWindow(Context &ctx) noexcept {
	glfwFocusWindow(ctx.window);
}

int getScreenWidth(Context const &ctx) noexcept {
	int w = 0, h = 0;
	glfwGetFramebufferSize(ctx.window, &w, &h);
	return w;
}

int getScreenHeight(Context const &ctx) noexcept {
	int w = 0, h = 0;
	glfwGetFramebufferSize(ctx.window, &w, &h);
	return h;
}

ox::Size getScreenSize(Context const &ctx) noexcept {
	int w = 0, h = 0;
	glfwGetFramebufferSize(ctx.window, &w, &h);
	return {w, h};
}

ox::Bounds getWindowBounds(Context const &ctx) noexcept {
	ox::Bounds bnds;
	glfwGetWindowPos(ctx.window, &bnds.x, &bnds.y);
	glfwGetWindowSize(ctx.window, &bnds.width, &bnds.height);
	return bnds;
}

ox::Error setWindowBounds(Context &ctx, ox::Bounds const&bnds) noexcept {
	glfwSetWindowPos(ctx.window, bnds.x, bnds.y);
	glfwSetWindowSize(ctx.window, bnds.width, bnds.height);
	return {};
}

void setRefreshWithin(Context &ctx, int ms) noexcept {
	ctx.refreshWithinMs = ox::min(ms, ctx.refreshWithinMs);
}

}