#include <graphics/math-defs.h>
#include <util/platform.h>
#include <util/util.hpp>
#include <obs-module.h>
#include <sys/stat.h>
#include <combaseapi.h>
#include <gdiplus.h>
#include <algorithm>
#include <string>
#include <memory>
#include <locale>

using namespace std;
using namespace Gdiplus;

#define warning(format, ...) blog(LOG_WARNING, "[%s] " format, obs_source_get_name(source), ##__VA_ARGS__)

#define warn_stat(call)                                                               \
	do {                                                                          \
		if (stat != Ok)                                                       \
			warning("%s: %s failed (%d)", __FUNCTION__, call, (int)stat); \
	} while (false)

#ifndef clamp
#define clamp(val, min_val, max_val) \
	if (val < min_val)           \
		val = min_val;       \
	else if (val > max_val)      \
		val = max_val;
#endif

#define MIN_SIZE_CX 2
#define MIN_SIZE_CY 2
#define MAX_SIZE_CX 16384
#define MAX_SIZE_CY 16384

#define MAX_AREA (4096LL * 4096LL)

/* ------------------------------------------------------------------------- */

/* clang-format off */

#define S_FONT                          "font"
#define S_USE_FILE                      "read_from_file"
#define S_FILE                          "file"
#define S_TEXT                          "text"
#define S_COLOR                         "color"
#define S_GRADIENT                      "gradient"
#define S_GRADIENT_COLOR                "gradient_color"
#define S_GRADIENT_DIR                  "gradient_dir"
#define S_GRADIENT_OPACITY              "gradient_opacity"
#define S_ALIGN                         "align"
#define S_VALIGN                        "valign"
#define S_OPACITY                       "opacity"
#define S_BKCOLOR                       "bk_color"
#define S_BKOPACITY                     "bk_opacity"
#define S_VERTICAL                      "vertical"
#define S_OUTLINE                       "outline"
#define S_OUTLINE_SIZE                  "outline_size"
#define S_OUTLINE_COLOR                 "outline_color"
#define S_OUTLINE_OPACITY               "outline_opacity"
#define S_CHATLOG_MODE                  "chatlog"
#define S_CHATLOG_LINES                 "chatlog_lines"
#define S_EXTENTS                       "extents"
#define S_EXTENTS_WRAP                  "extents_wrap"
#define S_EXTENTS_CX                    "extents_cx"
#define S_EXTENTS_CY                    "extents_cy"
#define S_TRANSFORM                     "transform"
#define S_ANTIALIASING                  "antialiasing"

#define S_ALIGN_LEFT                    "left"
#define S_ALIGN_CENTER                  "center"
#define S_ALIGN_RIGHT                   "right"

#define S_VALIGN_TOP                    "top"
#define S_VALIGN_CENTER                 S_ALIGN_CENTER
#define S_VALIGN_BOTTOM                 "bottom"

#define S_TRANSFORM_NONE                0
#define S_TRANSFORM_UPPERCASE           1
#define S_TRANSFORM_LOWERCASE           2
#define S_TRANSFORM_STARTCASE           3

#define T_(v)                           obs_module_text(v)
#define T_FONT                          T_("Font")
#define T_USE_FILE                      T_("ReadFromFile")
#define T_FILE                          T_("TextFile")
#define T_TEXT                          T_("Text")
#define T_COLOR                         T_("Color")
#define T_GRADIENT                      T_("Gradient")
#define T_GRADIENT_COLOR                T_("Gradient.Color")
#define T_GRADIENT_DIR                  T_("Gradient.Direction")
#define T_GRADIENT_OPACITY              T_("Gradient.Opacity")
#define T_ALIGN                         T_("Alignment")
#define T_VALIGN                        T_("VerticalAlignment")
#define T_OPACITY                       T_("Opacity")
#define T_BKCOLOR                       T_("BkColor")
#define T_BKOPACITY                     T_("BkOpacity")
#define T_VERTICAL                      T_("Vertical")
#define T_OUTLINE                       T_("Outline")
#define T_OUTLINE_SIZE                  T_("Outline.Size")
#define T_OUTLINE_COLOR                 T_("Outline.Color")
#define T_OUTLINE_OPACITY               T_("Outline.Opacity")
#define T_CHATLOG_MODE                  T_("ChatlogMode")
#define T_CHATLOG_LINES                 T_("ChatlogMode.Lines")
#define T_EXTENTS                       T_("UseCustomExtents")
#define T_EXTENTS_WRAP                  T_("UseCustomExtents.Wrap")
#define T_EXTENTS_CX                    T_("Width")
#define T_EXTENTS_CY                    T_("Height")
#define T_TRANSFORM                     T_("Transform")
#define T_ANTIALIASING                  T_("Antialiasing")

#define T_FILTER_TEXT_FILES             T_("Filter.TextFiles")
#define T_FILTER_ALL_FILES              T_("Filter.AllFiles")

#define T_ALIGN_LEFT                    T_("Alignment.Left")
#define T_ALIGN_CENTER                  T_("Alignment.Center")
#define T_ALIGN_RIGHT                   T_("Alignment.Right")

#define T_VALIGN_TOP                    T_("VerticalAlignment.Top")
#define T_VALIGN_CENTER                 T_ALIGN_CENTER
#define T_VALIGN_BOTTOM                 T_("VerticalAlignment.Bottom")

#define T_TRANSFORM_NONE                T_("Transform.None")
#define T_TRANSFORM_UPPERCASE           T_("Transform.Uppercase")
#define T_TRANSFORM_LOWERCASE           T_("Transform.Lowercase")
#define T_TRANSFORM_STARTCASE           T_("Transform.Startcase")

/* clang-format on */

/* ------------------------------------------------------------------------- */

static inline DWORD get_alpha_val(uint32_t opacity)
{
	return ((opacity * 255 / 100) & 0xFF) << 24;
}

static inline DWORD calc_color(uint32_t color, uint32_t opacity)
{
	return color & 0xFFFFFF | get_alpha_val(opacity);
}

static inline wstring to_wide(const char *utf8)
{
	wstring text;

	size_t len = os_utf8_to_wcs(utf8, 0, nullptr, 0);
	text.resize(len);
	if (len)
		os_utf8_to_wcs(utf8, 0, &text[0], len + 1);

	return text;
}

static inline uint32_t rgb_to_bgr(uint32_t rgb)
{
	return ((rgb & 0xFF) << 16) | (rgb & 0xFF00) | ((rgb & 0xFF0000) >> 16);
}

/* ------------------------------------------------------------------------- */

template<typename T, typename T2, BOOL WINAPI deleter(T2)> class GDIObj {
	T obj = nullptr;

	inline GDIObj &Replace(T obj_)
	{
		if (obj)
			deleter(obj);
		obj = obj_;
		return *this;
	}

public:
	inline GDIObj() {}
	inline GDIObj(T obj_) : obj(obj_) {}
	inline ~GDIObj() { deleter(obj); }

	inline T operator=(T obj_)
	{
		Replace(obj_);
		return obj;
	}

	inline operator T() const { return obj; }

	inline bool operator==(T obj_) const { return obj == obj_; }
	inline bool operator!=(T obj_) const { return obj != obj_; }
};

using HDCObj = GDIObj<HDC, HDC, DeleteDC>;
using HFONTObj = GDIObj<HFONT, HGDIOBJ, DeleteObject>;
using HBITMAPObj = GDIObj<HBITMAP, HGDIOBJ, DeleteObject>;

/* ------------------------------------------------------------------------- */

enum class Align {
	Left,
	Center,
	Right,
};

enum class VAlign {
	Top,
	Center,
	Bottom,
};

struct TextSource {
	obs_source_t *source = nullptr;

	gs_texture_t *tex = nullptr;
	uint32_t cx = 0;
	uint32_t cy = 0;

	HDCObj hdc;
	Graphics graphics;

	HFONTObj hfont;
	unique_ptr<Font> font;

	bool read_from_file = false;
	string file;
	time_t file_timestamp = 0;
	bool update_file = false;
	float update_time_elapsed = 0.0f;

	wstring text;
	wstring face;
	int face_size = 0;
	uint32_t color = 0xFFFFFF;
	uint32_t color2 = 0xFFFFFF;
	float gradient_dir = 0;
	uint32_t opacity = 100;
	uint32_t opacity2 = 100;
	uint32_t bk_color = 0;
	uint32_t bk_opacity = 0;
	Align align = Align::Left;
	VAlign valign = VAlign::Top;
	bool gradient = false;
	bool bold = false;
	bool italic = false;
	bool underline = false;
	bool strikeout = false;
	bool antialiasing = true;
	bool vertical = false;

	bool use_outline = false;
	float outline_size = 0.0f;
	uint32_t outline_color = 0;
	uint32_t outline_opacity = 100;

	bool use_extents = false;
	bool old_extents = false;
	bool wrap = false;
	uint32_t extents_cx = 0;
	uint32_t extents_cy = 0;

	int text_transform = S_TRANSFORM_NONE;

	bool chatlog_mode = false;
	int chatlog_lines = 6;

	/* --------------------------- */

	inline TextSource(obs_source_t *source_, obs_data_t *settings, bool old_extents_)
		: source(source_),
		  hdc(CreateCompatibleDC(nullptr)),
		  graphics(hdc),
		  old_extents(old_extents_)
	{
		obs_source_update(source, settings);
	}

	inline ~TextSource()
	{
		if (tex) {
			obs_enter_graphics();
			gs_texture_destroy(tex);
			obs_leave_graphics();
		}
	}

	void UpdateFont();
	void GetStringFormat(StringFormat &format);
	void RemoveNewlinePadding(const StringFormat &format, RectF &box);
	void CalculateTextSizes(const StringFormat &format, RectF &bounding_box, SIZE &text_size);
	void RenderOutlineText(Graphics &graphics, const GraphicsPath &path, const Brush &brush);
	void RenderText();
	void LoadFileText();
	void TransformText();
	void SetAntiAliasing(Graphics &graphics_bitmap);

	const char *GetMainString(const char *str);

	inline void Update(obs_data_t *settings);
	inline void Tick(float seconds);
	inline void Render();
};

static time_t get_modified_timestamp(const char *filename)
{
	struct stat stats;
	if (os_stat(filename, &stats) != 0)
		return -1;
	return stats.st_mtime;
}

void TextSource::UpdateFont()
{
	hfont = nullptr;
	font.reset(nullptr);

	LOGFONT lf = {};
	lf.lfHeight = face_size;
	lf.lfWeight = bold ? FW_BOLD : FW_DONTCARE;
	lf.lfItalic = italic;
	lf.lfUnderline = underline;
	lf.lfStrikeOut = strikeout;
	lf.lfQuality = ANTIALIASED_QUALITY;
	lf.lfCharSet = DEFAULT_CHARSET;

	if (!face.empty()) {
		wcscpy(lf.lfFaceName, face.c_str());
		hfont = CreateFontIndirect(&lf);
	}

	if (!hfont) {
		wcscpy(lf.lfFaceName, L"Arial");
		hfont = CreateFontIndirect(&lf);
	}

	if (hfont)
		font.reset(new Font(hdc, hfont));
}

void TextSource::GetStringFormat(StringFormat &format)
{
	UINT flags = StringFormatFlagsNoFitBlackBox;

	if (!use_extents || old_extents)
		flags |= StringFormatFlagsMeasureTrailingSpaces;

	if (vertical)
		flags |= StringFormatFlagsDirectionVertical | StringFormatFlagsDirectionRightToLeft;

	format.SetFormatFlags(flags);
	format.SetTrimming(StringTrimmingWord);

	switch (align) {
	case Align::Left:
		if (vertical)
			format.SetLineAlignment(StringAlignmentFar);
		else
			format.SetAlignment(StringAlignmentNear);
		break;
	case Align::Center:
		if (vertical)
			format.SetLineAlignment(StringAlignmentCenter);
		else
			format.SetAlignment(StringAlignmentCenter);
		break;
	case Align::Right:
		if (vertical)
			format.SetLineAlignment(StringAlignmentNear);
		else
			format.SetAlignment(StringAlignmentFar);
	}

	switch (valign) {
	case VAlign::Top:
		if (vertical)
			format.SetAlignment(StringAlignmentNear);
		else
			format.SetLineAlignment(StringAlignmentNear);
		break;
	case VAlign::Center:
		if (vertical)
			format.SetAlignment(StringAlignmentCenter);
		else
			format.SetLineAlignment(StringAlignmentCenter);
		break;
	case VAlign::Bottom:
		if (vertical)
			format.SetAlignment(StringAlignmentFar);
		else
			format.SetLineAlignment(StringAlignmentFar);
	}
}

/* GDI+ treats '\n' as an extra character with an actual render size when
 * calculating the texture size, so we have to calculate the size of '\n' to
 * remove the padding.  Because we always add a newline to the string, we
 * also remove the extra unused newline. */
void TextSource::RemoveNewlinePadding(const StringFormat &format, RectF &box)
{
	RectF before;
	RectF after;
	Status stat;

	stat = graphics.MeasureString(L"W", 2, font.get(), PointF(0.0f, 0.0f), &format, &before);
	warn_stat("MeasureString (without newline)");

	stat = graphics.MeasureString(L"W\n", 3, font.get(), PointF(0.0f, 0.0f), &format, &after);
	warn_stat("MeasureString (with newline)");

	float offset_cx = after.Width - before.Width;
	float offset_cy = after.Height - before.Height;

	if (!vertical) {
		if (offset_cx >= 1.0f)
			offset_cx -= 1.0f;

		if (valign == VAlign::Center)
			box.Y -= offset_cy * 0.5f;
		else if (valign == VAlign::Bottom)
			box.Y -= offset_cy;
	} else {
		if (offset_cy >= 1.0f)
			offset_cy -= 1.0f;

		if (align == Align::Center)
			box.X -= offset_cx * 0.5f;
		else if (align == Align::Right)
			box.X -= offset_cx;
	}

	box.Width -= offset_cx;
	box.Height -= offset_cy;
}

void TextSource::CalculateTextSizes(const StringFormat &format, RectF &bounding_box, SIZE &text_size)
{
	RectF layout_box;
	RectF temp_box;
	Status stat;

	if (!text.empty()) {
		if (use_extents && wrap) {
			layout_box.X = layout_box.Y = 0;
			layout_box.Width = float(extents_cx);
			layout_box.Height = float(extents_cy);

			if (use_outline) {
				layout_box.Width -= outline_size;
				layout_box.Height -= outline_size;
			}

			stat = graphics.MeasureString(text.c_str(), (int)text.size() + 1, font.get(), layout_box,
						      &format, &bounding_box);
			warn_stat("MeasureString (wrapped)");

			temp_box = bounding_box;
		} else {
			stat = graphics.MeasureString(text.c_str(), (int)text.size() + 1, font.get(),
						      PointF(0.0f, 0.0f), &format, &bounding_box);
			warn_stat("MeasureString (non-wrapped)");

			temp_box = bounding_box;

			bounding_box.X = 0.0f;
			bounding_box.Y = 0.0f;

			RemoveNewlinePadding(format, bounding_box);

			if (use_outline) {
				bounding_box.Width += outline_size;
				bounding_box.Height += outline_size;
			}
		}
	}

	if (vertical) {
		if (bounding_box.Width < face_size) {
			text_size.cx = face_size;
			bounding_box.Width = float(face_size);
		} else {
			text_size.cx = LONG(bounding_box.Width + EPSILON);
		}

		text_size.cy = LONG(bounding_box.Height + EPSILON);
	} else {
		if (bounding_box.Height < face_size) {
			text_size.cy = face_size;
			bounding_box.Height = float(face_size);
		} else {
			text_size.cy = LONG(bounding_box.Height + EPSILON);
		}

		text_size.cx = LONG(bounding_box.Width + EPSILON);
	}

	if (use_extents) {
		text_size.cx = extents_cx;
		text_size.cy = extents_cy;

		if (!old_extents && !wrap) {
			if (align == Align::Center) {
				bounding_box.X += (extents_cx - bounding_box.Width) / 2;
			} else if (align == Align::Right) {
				bounding_box.X += extents_cx - bounding_box.Width;
			}

			if (valign == VAlign::Center) {
				bounding_box.Y += (extents_cy - bounding_box.Height) / 2;
			} else if (valign == VAlign::Bottom) {
				bounding_box.Y += extents_cy - bounding_box.Height;
			}
		}
	}

	text_size.cx += text_size.cx % 2;
	text_size.cy += text_size.cy % 2;

	int64_t total_size = int64_t(text_size.cx) * int64_t(text_size.cy);

	/* GPUs typically have texture size limitations */
	clamp(text_size.cx, MIN_SIZE_CX, MAX_SIZE_CX);
	clamp(text_size.cy, MIN_SIZE_CY, MAX_SIZE_CY);

	/* avoid taking up too much VRAM */
	if (total_size > MAX_AREA) {
		if (text_size.cx > text_size.cy)
			text_size.cx = (LONG)MAX_AREA / text_size.cy;
		else
			text_size.cy = (LONG)MAX_AREA / text_size.cx;
	}

	/* the internal text-rendering bounding box for is reset to
	 * its internal value in case the texture gets cut off */
	bounding_box.Width = temp_box.Width;
	bounding_box.Height = temp_box.Height;
}

void TextSource::RenderOutlineText(Graphics &graphics, const GraphicsPath &path, const Brush &brush)
{
	DWORD outline_rgba = calc_color(outline_color, outline_opacity);
	Status stat;

	Pen pen(Color(outline_rgba), outline_size);
	stat = pen.SetLineJoin(LineJoinRound);
	warn_stat("pen.SetLineJoin");

	stat = graphics.DrawPath(&pen, &path);
	warn_stat("graphics.DrawPath");

	stat = graphics.FillPath(&brush, &path);
	warn_stat("graphics.FillPath");
}

void TextSource::RenderText()
{
	StringFormat format(StringFormat::GenericTypographic());
	Status stat;

	RectF box;
	SIZE size;

	GetStringFormat(format);
	CalculateTextSizes(format, box, size);

	unique_ptr<uint8_t[]> bits(new uint8_t[size.cx * size.cy * 4]);
	Bitmap bitmap(size.cx, size.cy, 4 * size.cx, PixelFormat32bppARGB, bits.get());

	Graphics graphics_bitmap(&bitmap);
	LinearGradientBrush brush(RectF(0, 0, (float)size.cx, (float)size.cy), Color(calc_color(color, opacity)),
				  Color(calc_color(color2, opacity2)), gradient_dir, 1);
	DWORD full_bk_color = bk_color & 0xFFFFFF;

	if (!text.empty() || use_extents)
		full_bk_color |= get_alpha_val(bk_opacity);

	if ((size.cx > box.Width || size.cy > box.Height) && !use_extents) {
		stat = graphics_bitmap.Clear(Color(0));
		warn_stat("graphics_bitmap.Clear");

		SolidBrush bk_brush = Color(full_bk_color);
		stat = graphics_bitmap.FillRectangle(&bk_brush, box);
		warn_stat("graphics_bitmap.FillRectangle");
	} else {
		stat = graphics_bitmap.Clear(Color(full_bk_color));
		warn_stat("graphics_bitmap.Clear");
	}

	graphics_bitmap.SetCompositingMode(CompositingModeSourceOver);
	SetAntiAliasing(graphics_bitmap);

	if (!text.empty()) {
		if (use_outline) {
			box.Offset(outline_size / 2, outline_size / 2);

			FontFamily family;
			GraphicsPath path;

			font->GetFamily(&family);
			stat = path.AddString(text.c_str(), (int)text.size(), &family, font->GetStyle(),
					      font->GetSize(), box, &format);
			warn_stat("path.AddString");

			RenderOutlineText(graphics_bitmap, path, brush);
		} else {
			stat = graphics_bitmap.DrawString(text.c_str(), (int)text.size(), font.get(), box, &format,
							  &brush);
			warn_stat("graphics_bitmap.DrawString");
		}
	}

	if (!tex || (LONG)cx != size.cx || (LONG)cy != size.cy) {
		obs_enter_graphics();
		if (tex)
			gs_texture_destroy(tex);

		const uint8_t *data = (uint8_t *)bits.get();
		tex = gs_texture_create(size.cx, size.cy, GS_BGRA, 1, &data, GS_DYNAMIC);

		obs_leave_graphics();

		cx = (uint32_t)size.cx;
		cy = (uint32_t)size.cy;

	} else if (tex) {
		obs_enter_graphics();
		gs_texture_set_image(tex, bits.get(), size.cx * 4, false);
		obs_leave_graphics();
	}
}

const char *TextSource::GetMainString(const char *str)
{
	if (!str)
		return "";
	if (!chatlog_mode || !chatlog_lines)
		return str;

	int lines = chatlog_lines;
	size_t len = strlen(str);
	if (!len)
		return str;

	const char *temp = str + len;

	while (temp != str) {
		temp--;

		if (temp[0] == '\n' && temp[1] != 0) {
			if (!--lines)
				break;
		}
	}

	return *temp == '\n' ? temp + 1 : temp;
}

void TextSource::LoadFileText()
{
	BPtr<char> file_text = os_quick_read_utf8_file(file.c_str());
	text = to_wide(GetMainString(file_text));

	if (!text.empty() && text.back() != '\n')
		text.push_back('\n');
}

void TextSource::TransformText()
{
	const locale loc = locale(obs_get_locale());
	const ctype<wchar_t> &f = use_facet<ctype<wchar_t>>(loc);
	if (text_transform == S_TRANSFORM_UPPERCASE)
		f.toupper(&text[0], &text[0] + text.size());
	else if (text_transform == S_TRANSFORM_LOWERCASE)
		f.tolower(&text[0], &text[0] + text.size());
	else if (text_transform == S_TRANSFORM_STARTCASE) {
		bool upper = true;
		for (wstring::iterator it = text.begin(); it != text.end(); ++it) {
			const wchar_t upper_char = f.toupper(*it);
			const wchar_t lower_char = f.tolower(*it);
			if (upper && lower_char != upper_char) {
				upper = false;
				*it = upper_char;
			} else if (lower_char != upper_char) {
				*it = lower_char;
			} else {
				upper = iswspace(*it);
			}
		}
	}
}

void TextSource::SetAntiAliasing(Graphics &graphics_bitmap)
{
	if (!antialiasing) {
		graphics_bitmap.SetTextRenderingHint(TextRenderingHintSingleBitPerPixel);
		graphics_bitmap.SetSmoothingMode(SmoothingModeNone);
		return;
	}

	graphics_bitmap.SetTextRenderingHint(TextRenderingHintAntiAlias);
	graphics_bitmap.SetSmoothingMode(SmoothingModeAntiAlias);
}

#define obs_data_get_uint32 (uint32_t) obs_data_get_int

inline void TextSource::Update(obs_data_t *s)
{
	const char *new_text = obs_data_get_string(s, S_TEXT);
	obs_data_t *font_obj = obs_data_get_obj(s, S_FONT);
	const char *align_str = obs_data_get_string(s, S_ALIGN);
	const char *valign_str = obs_data_get_string(s, S_VALIGN);
	uint32_t new_color = obs_data_get_uint32(s, S_COLOR);
	uint32_t new_opacity = obs_data_get_uint32(s, S_OPACITY);
	bool gradient = obs_data_get_bool(s, S_GRADIENT);
	uint32_t new_color2 = obs_data_get_uint32(s, S_GRADIENT_COLOR);
	uint32_t new_opacity2 = obs_data_get_uint32(s, S_GRADIENT_OPACITY);
	float new_grad_dir = (float)obs_data_get_double(s, S_GRADIENT_DIR);
	bool new_vertical = obs_data_get_bool(s, S_VERTICAL);
	bool new_outline = obs_data_get_bool(s, S_OUTLINE);
	uint32_t new_o_color = obs_data_get_uint32(s, S_OUTLINE_COLOR);
	uint32_t new_o_opacity = obs_data_get_uint32(s, S_OUTLINE_OPACITY);
	uint32_t new_o_size = obs_data_get_uint32(s, S_OUTLINE_SIZE);
	bool new_use_file = obs_data_get_bool(s, S_USE_FILE);
	const char *new_file = obs_data_get_string(s, S_FILE);
	bool new_chat_mode = obs_data_get_bool(s, S_CHATLOG_MODE);
	int new_chat_lines = (int)obs_data_get_int(s, S_CHATLOG_LINES);
	bool new_extents = obs_data_get_bool(s, S_EXTENTS);
	bool new_extents_wrap = obs_data_get_bool(s, S_EXTENTS_WRAP);
	uint32_t n_extents_cx = obs_data_get_uint32(s, S_EXTENTS_CX);
	uint32_t n_extents_cy = obs_data_get_uint32(s, S_EXTENTS_CY);
	int new_text_transform = (int)obs_data_get_int(s, S_TRANSFORM);
	bool new_antialiasing = obs_data_get_bool(s, S_ANTIALIASING);

	const char *font_face = obs_data_get_string(font_obj, "face");
	int font_size = (int)obs_data_get_int(font_obj, "size");
	int64_t font_flags = obs_data_get_int(font_obj, "flags");
	bool new_bold = (font_flags & OBS_FONT_BOLD) != 0;
	bool new_italic = (font_flags & OBS_FONT_ITALIC) != 0;
	bool new_underline = (font_flags & OBS_FONT_UNDERLINE) != 0;
	bool new_strikeout = (font_flags & OBS_FONT_STRIKEOUT) != 0;

	uint32_t new_bk_color = obs_data_get_uint32(s, S_BKCOLOR);
	uint32_t new_bk_opacity = obs_data_get_uint32(s, S_BKOPACITY);

	/* ----------------------------- */

	wstring new_face = to_wide(font_face);

	if (new_face != face || face_size != font_size || new_bold != bold || new_italic != italic ||
	    new_underline != underline || new_strikeout != strikeout) {

		face = new_face;
		face_size = font_size;
		bold = new_bold;
		italic = new_italic;
		underline = new_underline;
		strikeout = new_strikeout;

		UpdateFont();
	}

	/* ----------------------------- */

	new_color = rgb_to_bgr(new_color);
	new_color2 = rgb_to_bgr(new_color2);
	new_o_color = rgb_to_bgr(new_o_color);
	new_bk_color = rgb_to_bgr(new_bk_color);

	color = new_color;
	opacity = new_opacity;
	color2 = new_color2;
	opacity2 = new_opacity2;
	gradient_dir = new_grad_dir;
	vertical = new_vertical;

	bk_color = new_bk_color;
	bk_opacity = new_bk_opacity;
	use_extents = new_extents;
	wrap = new_extents_wrap;
	extents_cx = n_extents_cx;
	extents_cy = n_extents_cy;
	text_transform = new_text_transform;
	antialiasing = new_antialiasing;

	if (!gradient) {
		color2 = color;
		opacity2 = opacity;
	}

	read_from_file = new_use_file;

	chatlog_mode = new_chat_mode;
	chatlog_lines = new_chat_lines;

	if (read_from_file) {
		file = new_file;
		file_timestamp = get_modified_timestamp(new_file);
		LoadFileText();

	} else {
		text = to_wide(GetMainString(new_text));

		/* all text should end with newlines due to the fact that GDI+
		 * treats strings without newlines differently in terms of
		 * render size */
		if (!text.empty())
			text.push_back('\n');
	}
	TransformText();

	use_outline = new_outline;
	outline_color = new_o_color;
	outline_opacity = new_o_opacity;
	outline_size = roundf(float(new_o_size));

	if (strcmp(align_str, S_ALIGN_CENTER) == 0)
		align = Align::Center;
	else if (strcmp(align_str, S_ALIGN_RIGHT) == 0)
		align = Align::Right;
	else
		align = Align::Left;

	if (strcmp(valign_str, S_VALIGN_CENTER) == 0)
		valign = VAlign::Center;
	else if (strcmp(valign_str, S_VALIGN_BOTTOM) == 0)
		valign = VAlign::Bottom;
	else
		valign = VAlign::Top;

	RenderText();
	update_time_elapsed = 0.0f;

	/* ----------------------------- */

	obs_data_release(font_obj);
}

inline void TextSource::Tick(float seconds)
{
	if (!read_from_file)
		return;

	update_time_elapsed += seconds;

	if (update_time_elapsed >= 1.0f) {
		time_t t = get_modified_timestamp(file.c_str());
		update_time_elapsed = 0.0f;

		if (update_file) {
			LoadFileText();
			TransformText();
			RenderText();
			update_file = false;
		}

		if (file_timestamp != t) {
			file_timestamp = t;
			update_file = true;
		}
	}
}

inline void TextSource::Render()
{
	if (!tex)
		return;

	gs_effect_t *effect = obs_get_base_effect(OBS_EFFECT_DEFAULT);
	gs_technique_t *tech = gs_effect_get_technique(effect, "Draw");

	const bool previous = gs_framebuffer_srgb_enabled();
	gs_enable_framebuffer_srgb(true);

	gs_technique_begin(tech);
	gs_technique_begin_pass(tech, 0);

	gs_effect_set_texture_srgb(gs_effect_get_param_by_name(effect, "image"), tex);
	gs_draw_sprite(tex, 0, cx, cy);

	gs_technique_end_pass(tech);
	gs_technique_end(tech);

	gs_enable_framebuffer_srgb(previous);
}

/* ------------------------------------------------------------------------- */

static ULONG_PTR gdip_token = 0;

OBS_DECLARE_MODULE()
OBS_MODULE_USE_DEFAULT_LOCALE("obs-text", "en-US")
MODULE_EXPORT const char *obs_module_description(void)
{
	return "Windows GDI+ text source";
}

#define set_vis(var, val, show)                           \
	do {                                              \
		p = obs_properties_get(props, val);       \
		obs_property_set_visible(p, var == show); \
	} while (false)

static bool use_file_changed(obs_properties_t *props, obs_property_t *p, obs_data_t *s)
{
	bool use_file = obs_data_get_bool(s, S_USE_FILE);

	set_vis(use_file, S_TEXT, false);
	set_vis(use_file, S_FILE, true);
	return true;
}

static bool outline_changed(obs_properties_t *props, obs_property_t *p, obs_data_t *s)
{
	bool outline = obs_data_get_bool(s, S_OUTLINE);

	set_vis(outline, S_OUTLINE_SIZE, true);
	set_vis(outline, S_OUTLINE_COLOR, true);
	set_vis(outline, S_OUTLINE_OPACITY, true);
	return true;
}

static bool chatlog_mode_changed(obs_properties_t *props, obs_property_t *p, obs_data_t *s)
{
	bool chatlog_mode = obs_data_get_bool(s, S_CHATLOG_MODE);

	set_vis(chatlog_mode, S_CHATLOG_LINES, true);
	return true;
}

static bool gradient_changed(obs_properties_t *props, obs_property_t *p, obs_data_t *s)
{
	bool gradient = obs_data_get_bool(s, S_GRADIENT);

	set_vis(gradient, S_GRADIENT_COLOR, true);
	set_vis(gradient, S_GRADIENT_OPACITY, true);
	set_vis(gradient, S_GRADIENT_DIR, true);
	return true;
}

static bool extents_modified(obs_properties_t *props, obs_property_t *p, obs_data_t *s)
{
	bool use_extents = obs_data_get_bool(s, S_EXTENTS);

	set_vis(use_extents, S_EXTENTS_WRAP, true);
	set_vis(use_extents, S_EXTENTS_CX, true);
	set_vis(use_extents, S_EXTENTS_CY, true);
	return true;
}

#undef set_vis

static obs_properties_t *get_properties(void *data)
{
	TextSource *s = reinterpret_cast<TextSource *>(data);
	string path;

	obs_properties_t *props = obs_properties_create();
	obs_property_t *p;

	obs_properties_add_font(props, S_FONT, T_FONT);

	p = obs_properties_add_bool(props, S_USE_FILE, T_USE_FILE);
	obs_property_set_modified_callback(p, use_file_changed);

	string filter;
	filter += T_FILTER_TEXT_FILES;
	filter += " (*.txt);;";
	filter += T_FILTER_ALL_FILES;
	filter += " (*.*)";

	if (s && !s->file.empty()) {
		const char *slash;

		path = s->file;
		replace(path.begin(), path.end(), '\\', '/');
		slash = strrchr(path.c_str(), '/');
		if (slash)
			path.resize(slash - path.c_str() + 1);
	}

	obs_properties_add_text(props, S_TEXT, T_TEXT, OBS_TEXT_MULTILINE);
	obs_properties_add_path(props, S_FILE, T_FILE, OBS_PATH_FILE, filter.c_str(), path.c_str());

	obs_properties_add_bool(props, S_ANTIALIASING, T_ANTIALIASING);

	p = obs_properties_add_list(props, S_TRANSFORM, T_TRANSFORM, OBS_COMBO_TYPE_LIST, OBS_COMBO_FORMAT_INT);
	obs_property_list_add_int(p, T_TRANSFORM_NONE, S_TRANSFORM_NONE);
	obs_property_list_add_int(p, T_TRANSFORM_UPPERCASE, S_TRANSFORM_UPPERCASE);
	obs_property_list_add_int(p, T_TRANSFORM_LOWERCASE, S_TRANSFORM_LOWERCASE);
	obs_property_list_add_int(p, T_TRANSFORM_STARTCASE, S_TRANSFORM_STARTCASE);

	obs_properties_add_bool(props, S_VERTICAL, T_VERTICAL);

	obs_properties_add_color(props, S_COLOR, T_COLOR);
	p = obs_properties_add_int_slider(props, S_OPACITY, T_OPACITY, 0, 100, 1);
	obs_property_int_set_suffix(p, "%");

	p = obs_properties_add_bool(props, S_GRADIENT, T_GRADIENT);
	obs_property_set_modified_callback(p, gradient_changed);

	obs_properties_add_color(props, S_GRADIENT_COLOR, T_GRADIENT_COLOR);
	p = obs_properties_add_int_slider(props, S_GRADIENT_OPACITY, T_GRADIENT_OPACITY, 0, 100, 1);
	obs_property_int_set_suffix(p, "%");
	obs_properties_add_float_slider(props, S_GRADIENT_DIR, T_GRADIENT_DIR, 0, 360, 0.1);

	obs_properties_add_color(props, S_BKCOLOR, T_BKCOLOR);
	p = obs_properties_add_int_slider(props, S_BKOPACITY, T_BKOPACITY, 0, 100, 1);
	obs_property_int_set_suffix(p, "%");

	p = obs_properties_add_list(props, S_ALIGN, T_ALIGN, OBS_COMBO_TYPE_LIST, OBS_COMBO_FORMAT_STRING);
	obs_property_list_add_string(p, T_ALIGN_LEFT, S_ALIGN_LEFT);
	obs_property_list_add_string(p, T_ALIGN_CENTER, S_ALIGN_CENTER);
	obs_property_list_add_string(p, T_ALIGN_RIGHT, S_ALIGN_RIGHT);

	p = obs_properties_add_list(props, S_VALIGN, T_VALIGN, OBS_COMBO_TYPE_LIST, OBS_COMBO_FORMAT_STRING);
	obs_property_list_add_string(p, T_VALIGN_TOP, S_VALIGN_TOP);
	obs_property_list_add_string(p, T_VALIGN_CENTER, S_VALIGN_CENTER);
	obs_property_list_add_string(p, T_VALIGN_BOTTOM, S_VALIGN_BOTTOM);

	p = obs_properties_add_bool(props, S_OUTLINE, T_OUTLINE);
	obs_property_set_modified_callback(p, outline_changed);

	obs_properties_add_int(props, S_OUTLINE_SIZE, T_OUTLINE_SIZE, 1, 20, 1);
	obs_properties_add_color(props, S_OUTLINE_COLOR, T_OUTLINE_COLOR);
	p = obs_properties_add_int_slider(props, S_OUTLINE_OPACITY, T_OUTLINE_OPACITY, 0, 100, 1);
	obs_property_int_set_suffix(p, "%");

	p = obs_properties_add_bool(props, S_CHATLOG_MODE, T_CHATLOG_MODE);
	obs_property_set_modified_callback(p, chatlog_mode_changed);

	obs_properties_add_int(props, S_CHATLOG_LINES, T_CHATLOG_LINES, 1, 1000, 1);

	p = obs_properties_add_bool(props, S_EXTENTS, T_EXTENTS);
	obs_property_set_modified_callback(p, extents_modified);

	obs_properties_add_int(props, S_EXTENTS_CX, T_EXTENTS_CX, 32, 8000, 1);
	obs_properties_add_int(props, S_EXTENTS_CY, T_EXTENTS_CY, 32, 8000, 1);
	obs_properties_add_bool(props, S_EXTENTS_WRAP, T_EXTENTS_WRAP);

	return props;
}

static void defaults(obs_data_t *settings, int ver)
{
	obs_data_t *font_obj = obs_data_create();
	obs_data_set_default_string(font_obj, "face", "Arial");
	obs_data_set_default_int(font_obj, "size", ver == 1 ? 36 : 256);

	obs_data_set_default_obj(settings, S_FONT, font_obj);
	obs_data_set_default_string(settings, S_ALIGN, S_ALIGN_LEFT);
	obs_data_set_default_string(settings, S_VALIGN, S_VALIGN_TOP);
	obs_data_set_default_int(settings, S_COLOR, 0xFFFFFF);
	obs_data_set_default_int(settings, S_OPACITY, 100);
	obs_data_set_default_int(settings, S_GRADIENT_COLOR, 0xFFFFFF);
	obs_data_set_default_int(settings, S_GRADIENT_OPACITY, 100);
	obs_data_set_default_double(settings, S_GRADIENT_DIR, 90.0);
	obs_data_set_default_int(settings, S_BKCOLOR, 0x000000);
	obs_data_set_default_int(settings, S_BKOPACITY, 0);
	obs_data_set_default_int(settings, S_OUTLINE_SIZE, 2);
	obs_data_set_default_int(settings, S_OUTLINE_COLOR, 0xFFFFFF);
	obs_data_set_default_int(settings, S_OUTLINE_OPACITY, 100);
	obs_data_set_default_int(settings, S_CHATLOG_LINES, 6);
	obs_data_set_default_bool(settings, S_EXTENTS_WRAP, true);
	obs_data_set_default_int(settings, S_EXTENTS_CX, 100);
	obs_data_set_default_int(settings, S_EXTENTS_CY, 100);
	obs_data_set_default_int(settings, S_TRANSFORM, S_TRANSFORM_NONE);
	obs_data_set_default_bool(settings, S_ANTIALIASING, true);

	obs_data_release(font_obj);
};

static void missing_file_callback(void *src, const char *new_path, void *data)
{
	TextSource *s = reinterpret_cast<TextSource *>(src);

	obs_source_t *source = s->source;
	obs_data_t *settings = obs_source_get_settings(source);
	obs_data_set_string(settings, S_FILE, new_path);
	obs_source_update(source, settings);
	obs_data_release(settings);

	UNUSED_PARAMETER(data);
}

bool obs_module_load(void)
{
	obs_source_info si = {};
	si.id = "text_gdiplus";
	si.type = OBS_SOURCE_TYPE_INPUT;
	si.output_flags = OBS_SOURCE_VIDEO | OBS_SOURCE_CUSTOM_DRAW | OBS_SOURCE_CAP_OBSOLETE | OBS_SOURCE_SRGB;
	si.get_properties = get_properties;
	si.icon_type = OBS_ICON_TYPE_TEXT;

	si.get_name = [](void *) {
		return obs_module_text("TextGDIPlus");
	};
	si.create = [](obs_data_t *settings, obs_source_t *source) {
		return (void *)new TextSource(source, settings, true);
	};
	si.destroy = [](void *data) {
		delete reinterpret_cast<TextSource *>(data);
	};
	si.get_width = [](void *data) {
		return reinterpret_cast<TextSource *>(data)->cx;
	};
	si.get_height = [](void *data) {
		return reinterpret_cast<TextSource *>(data)->cy;
	};
	si.get_defaults = [](obs_data_t *settings) {
		defaults(settings, 1);
	};
	si.update = [](void *data, obs_data_t *settings) {
		reinterpret_cast<TextSource *>(data)->Update(settings);
	};
	si.video_tick = [](void *data, float seconds) {
		reinterpret_cast<TextSource *>(data)->Tick(seconds);
	};
	si.video_render = [](void *data, gs_effect_t *) {
		reinterpret_cast<TextSource *>(data)->Render();
	};
	si.missing_files = [](void *data) {
		TextSource *s = reinterpret_cast<TextSource *>(data);
		obs_missing_files_t *files = obs_missing_files_create();

		obs_source_t *source = s->source;
		obs_data_t *settings = obs_source_get_settings(source);

		bool read = obs_data_get_bool(settings, S_USE_FILE);
		const char *path = obs_data_get_string(settings, S_FILE);

		if (read && strcmp(path, "") != 0) {
			if (!os_file_exists(path)) {
				obs_missing_file_t *file = obs_missing_file_create(
					path, missing_file_callback, OBS_MISSING_FILE_SOURCE, s->source, NULL);

				obs_missing_files_add_file(files, file);
			}
		}

		obs_data_release(settings);

		return files;
	};

	obs_source_info si_v2 = si;
	si_v2.version = 2;
	si_v2.get_defaults = [](obs_data_t *settings) {
		defaults(settings, 2);
	};

	obs_source_info si_v3 = si_v2;
	si_v3.version = 3;
	si_v3.output_flags &= ~OBS_SOURCE_CAP_OBSOLETE;
	si_v3.create = [](obs_data_t *settings, obs_source_t *source) {
		return (void *)new TextSource(source, settings, false);
	};

	obs_register_source(&si);
	obs_register_source(&si_v2);
	obs_register_source(&si_v3);

	const GdiplusStartupInput gdip_input;
	GdiplusStartup(&gdip_token, &gdip_input, nullptr);
	return true;
}

void obs_module_unload(void)
{
	GdiplusShutdown(gdip_token);
}
