// Scintilla source code edit control
/** @file Indicator.cxx
 ** Defines the style of indicators which are text decorations such as underlining.
 **/
// Copyright 1998-2001 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

#include <cmath>

#include <stdexcept>
#include <string_view>
#include <vector>
#include <map>
#include <algorithm>
#include <memory>

#include "Platform.h"

#include "Scintilla.h"
#include "IntegerRectangle.h"
#include "Indicator.h"
#include "XPM.h"

using namespace Scintilla;

static PRectangle PixelGridAlign(const PRectangle &rc) noexcept {
	// Move left and right side to nearest pixel to avoid blurry visuals
	return PRectangle(std::round(rc.left), std::floor(rc.top),
		std::round(rc.right), std::floor(rc.bottom));
}

void Indicator::Draw(Surface *surface, const PRectangle &rc, const PRectangle &rcLine, const PRectangle &rcCharacter, State state, int value) const {
	StyleAndColour sacDraw = sacNormal;
	if (Flags() & SC_INDICFLAG_VALUEFORE) {
		sacDraw.fore = ColourDesired(value & SC_INDICVALUEMASK);
	}
	if (state == State::hover) {
		sacDraw = sacHover;
	}
	const IntegerRectangle irc(rc);
	surface->PenColour(sacDraw.fore);
	const int ymid = (irc.bottom + irc.top) / 2;

	switch (sacDraw.style) {
	case INDIC_SQUIGGLE: {
			const IntegerRectangle ircSquiggle(PixelGridAlign(rc));
			int x = ircSquiggle.left;
			const int xLast = ircSquiggle.right;
			int y = 0;
			surface->MoveTo(x, irc.top + y);
			while (x < xLast) {
				if ((x + 2) > xLast) {
					y = 1;
					x = xLast;
				} else {
					x += 2;
					y = 2 - y;
				}
				surface->LineTo(x, irc.top + y);
			}
		}
		break;

	case INDIC_SQUIGGLEPIXMAP: {
			const PRectangle rcSquiggle = PixelGridAlign(rc);

			const int width = std::min(4000, static_cast<int>(rcSquiggle.Width()));
			RGBAImage image(width, 3, 1.0, nullptr);
			enum { alphaFull = 0xff, alphaSide = 0x2f, alphaSide2=0x5f };
			for (int x = 0; x < width; x++) {
				if (x%2) {
					// Two halfway columns have a full pixel in middle flanked by light pixels
					image.SetPixel(x, 0, sacDraw.fore, alphaSide);
					image.SetPixel(x, 1, sacDraw.fore, alphaFull);
					image.SetPixel(x, 2, sacDraw.fore, alphaSide);
				} else {
					// Extreme columns have a full pixel at bottom or top and a mid-tone pixel in centre
					image.SetPixel(x, (x % 4) ? 0 : 2, sacDraw.fore, alphaFull);
					image.SetPixel(x, 1, sacDraw.fore, alphaSide2);
				}
			}
			surface->DrawRGBAImage(rcSquiggle, image.GetWidth(), image.GetHeight(), image.Pixels());
		}
		break;

	case INDIC_SQUIGGLELOW: {
			surface->MoveTo(irc.left, irc.top);
			int x = irc.left + 3;
			int y = 0;
			while (x < rc.right) {
				surface->LineTo(x - 1, irc.top + y);
				y = 1 - y;
				surface->LineTo(x, irc.top + y);
				x += 3;
			}
			surface->LineTo(irc.right, irc.top + y);	// Finish the line
		}
		break;

	case INDIC_TT: {
			surface->MoveTo(irc.left, ymid);
			int x = irc.left + 5;
			while (x < rc.right) {
				surface->LineTo(x, ymid);
				surface->MoveTo(x-3, ymid);
				surface->LineTo(x-3, ymid+2);
				x++;
				surface->MoveTo(x, ymid);
				x += 5;
			}
			surface->LineTo(irc.right, ymid);	// Finish the line
			if (x - 3 <= rc.right) {
				surface->MoveTo(x-3, ymid);
				surface->LineTo(x-3, ymid+2);
			}
		}
		break;

	case INDIC_DIAGONAL: {
			int x = irc.left;
			while (x < rc.right) {
				surface->MoveTo(x, irc.top + 2);
				int endX = x+3;
				int endY = irc.top - 1;
				if (endX > rc.right) {
					endY += endX - irc.right;
					endX = irc.right;
				}
				surface->LineTo(endX, endY);
				x += 4;
			}
		}
		break;

	case INDIC_STRIKE: {
			surface->MoveTo(irc.left, irc.top - 4);
			surface->LineTo(irc.right, irc.top - 4);
		}
		break;

	case INDIC_HIDDEN:
	case INDIC_TEXTFORE:
		// Draw nothing
		break;

	case INDIC_BOX: {
			surface->MoveTo(irc.left, ymid + 1);
			surface->LineTo(irc.right, ymid + 1);
			const int lineTop = static_cast<int>(rcLine.top) + 1;
			surface->LineTo(irc.right, lineTop);
			surface->LineTo(irc.left, lineTop);
			surface->LineTo(irc.left, ymid + 1);
		}
		break;

	case INDIC_ROUNDBOX:
	case INDIC_STRAIGHTBOX:
	case INDIC_FULLBOX: {
			PRectangle rcBox = rcLine;
			if (sacDraw.style != INDIC_FULLBOX)
				rcBox.top = rcLine.top + 1;
			rcBox.left = rc.left;
			rcBox.right = rc.right;
			surface->AlphaRectangle(rcBox, (sacDraw.style == INDIC_ROUNDBOX) ? 1 : 0,
						sacDraw.fore, fillAlpha, sacDraw.fore, outlineAlpha, 0);
		}
		break;

	case INDIC_GRADIENT:
	case INDIC_GRADIENTCENTRE: {
			PRectangle rcBox = rc;
			rcBox.top = rcLine.top + 1;
			rcBox.bottom = rcLine.bottom;
			const Surface::GradientOptions options = Surface::GradientOptions::topToBottom;
			const ColourAlpha start(sacDraw.fore, fillAlpha);
			const ColourAlpha end(sacDraw.fore, 0);
			std::vector<ColourStop> stops;
			switch (sacDraw.style) {
			case INDIC_GRADIENT:
				stops.push_back(ColourStop(0.0, start));
				stops.push_back(ColourStop(1.0, end));
				break;
			case INDIC_GRADIENTCENTRE:
				stops.push_back(ColourStop(0.0, end));
				stops.push_back(ColourStop(0.5, start));
				stops.push_back(ColourStop(1.0, end));
				break;
			}
			surface->GradientRectangle(rcBox, stops, options);
		}
		break;

	case INDIC_DOTBOX: {
			PRectangle rcBox = PixelGridAlign(rc);
			rcBox.top = rcLine.top + 1;
			rcBox.bottom = rcLine.bottom;
			const IntegerRectangle ircBox(rcBox);
			// Cap width at 4000 to avoid large allocations when mistakes made
			const int width = std::min(ircBox.Width(), 4000);
			RGBAImage image(width, ircBox.Height(), 1.0, nullptr);
			// Draw horizontal lines top and bottom
			for (int x=0; x<width; x++) {
				for (int y = 0; y<ircBox.Height(); y += ircBox.Height() - 1) {
					image.SetPixel(x, y, sacDraw.fore, ((x + y) % 2) ? outlineAlpha : fillAlpha);
				}
			}
			// Draw vertical lines left and right
			for (int y = 1; y<ircBox.Height(); y++) {
				for (int x=0; x<width; x += width-1) {
					image.SetPixel(x, y, sacDraw.fore, ((x + y) % 2) ? outlineAlpha : fillAlpha);
				}
			}
			surface->DrawRGBAImage(rcBox, image.GetWidth(), image.GetHeight(), image.Pixels());
		}
		break;

	case INDIC_DASH: {
			int x = irc.left;
			while (x < rc.right) {
				surface->MoveTo(x, ymid);
				surface->LineTo(std::min(x + 4, irc.right), ymid);
				x += 7;
			}
		}
		break;

	case INDIC_DOTS: {
			int x = irc.left;
			while (x < irc.right) {
				const PRectangle rcDot = PRectangle::FromInts(x, ymid, x + 1, ymid + 1);
				surface->FillRectangle(rcDot, sacDraw.fore);
				x += 2;
			}
		}
		break;

	case INDIC_COMPOSITIONTHICK: {
			const PRectangle rcComposition(rc.left+1, rcLine.bottom-2, rc.right-1, rcLine.bottom);
			surface->FillRectangle(rcComposition, sacDraw.fore);
		}
		break;

	case INDIC_COMPOSITIONTHIN: {
			const PRectangle rcComposition(rc.left+1, rcLine.bottom-2, rc.right-1, rcLine.bottom-1);
			surface->FillRectangle(rcComposition, sacDraw.fore);
		}
		break;

	case INDIC_POINT:
	case INDIC_POINTCHARACTER:
		if (rcCharacter.Width() >= 0.1) {
			const XYPOSITION pixelHeight = std::floor(rc.Height() - 1.0f);	// 1 pixel onto next line if multiphase
			const XYPOSITION x = (sacDraw.style == INDIC_POINT) ? (rcCharacter.left) : ((rcCharacter.right + rcCharacter.left) / 2);
			const XYPOSITION ix = std::round(x);
			const XYPOSITION iy = std::floor(rc.top + 1.0f);
			Point pts[] = {
				Point(ix - pixelHeight, iy + pixelHeight),	// Left
				Point(ix + pixelHeight, iy + pixelHeight),	// Right
				Point(ix, iy)								// Top
			};
			surface->Polygon(pts, std::size(pts), sacDraw.fore, sacDraw.fore);
		}
		break;

	default:
		// Either INDIC_PLAIN or unknown
		surface->MoveTo(irc.left, ymid);
		surface->LineTo(irc.right, ymid);
	}
}

void Indicator::SetFlags(int attributes_) noexcept {
	attributes = attributes_;
}
