/*
 * REminiscence - Flashback interpreter
 * Copyright (C) 2005-2018 Gregory Montoir (cyx@users.sourceforge.net)
 */

#include "scaler.h"
#include "dynlib.h"
#include "util.h"

static void scale2x(uint32_t *dst, int dstPitch, const uint32_t *src, int srcPitch, int w, int h) {
	const int dstPitch2 = dstPitch * 2;
	for (int y = 0; y < h; ++y) {
		uint32_t *p = dst;
		for (int x = 0; x < w; ++x, p += 2) {
			const uint32_t E = *(src + x);
			const uint32_t B = (y == 0) ? E : *(src + x - srcPitch);
			const uint32_t D = (x == 0) ? E : *(src + x - 1);
			const uint32_t F = (x == w - 1) ? E : *(src + x + 1);
			const uint32_t H = (y == h - 1) ? E : *(src + x + srcPitch);
			if (B != H && D != F) {
				*(p) = D == B ? D : E;
				*(p + 1) = B == F ? F : E;
				*(p + dstPitch) = D == H ? D : E;
				*(p + dstPitch + 1) = H == F ? F : E;
			} else {
				*(p) = E;
				*(p + 1) = E;
				*(p + dstPitch) = E;
				*(p + dstPitch + 1) = E;
			}
		}
		dst += dstPitch2;
		src += srcPitch;
	}
}

static void scale3x(uint32_t *dst, int dstPitch, const uint32_t *src, int srcPitch, int w, int h) {
	const int dstPitch2 = dstPitch * 2;
	const int dstPitch3 = dstPitch * 3;
	for (int y = 0; y < h; ++y) {
		uint32_t *p = dst;
		for (int x = 0; x < w; ++x, p += 3) {
			const uint32_t E = *(src + x);
			const uint32_t B = (y == 0) ? E : *(src + x - srcPitch);
			const uint32_t D = (x == 0) ? E : *(src + x - 1);
			const uint32_t F = (x == w - 1) ? E : *(src + x + 1);
			const uint32_t H = (y == h - 1) ? E : *(src + x + srcPitch);
			uint32_t A, C;
			if (y == 0) {
				A = D;
				C = F;
			} else {
				A = (x == 0) ? B : *(src + x - srcPitch - 1);
				C = (x == w - 1) ? B : *(src + x - srcPitch + 1);
			}
			uint32_t G, I;
			if (y == h - 1) {
				G = D;
				I = F;
			} else {
				G = (x == 0) ? H : *(src + x + srcPitch - 1);
				I = (x == w - 1) ? H : *(src + x + srcPitch + 1);
			}
			if (B != H && D != F) {
				*(p) = D == B ? D : E;
				*(p + 1) = (D == B && E != C) || (B == F && E != A) ? B : E;
				*(p + 2) = B == F ? F : E;
				*(p + dstPitch) = (D == B && E != G) || (D == B && E != A) ? D : E;
				*(p + dstPitch + 1) = E;
				*(p + dstPitch + 2) = (B == F && E != I) || (H == F && E != C) ? F : E;
				*(p + dstPitch2) = D == H ? D : E;
				*(p + dstPitch2 + 1) = (D == H && E != I) || (H == F && E != G) ? H : E;
				*(p + dstPitch2 + 2) = H == F ? F : E;
			} else {
				*(p) = E;
				*(p + 1) = E;
				*(p + 2) = E;
				*(p + dstPitch) = E;
				*(p + dstPitch + 1) = E;
				*(p + dstPitch + 2) = E;
				*(p + dstPitch2) = E;
				*(p + dstPitch2 + 1) = E;
				*(p + dstPitch2 + 2) = E;
			}
		}
		dst += dstPitch3;
		src += srcPitch;
	}
}

static void scale4x(uint32_t *dst, int dstPitch, const uint32_t *src, int srcPitch, int w, int h) {
	static struct {
		uint32_t *ptr;
		int w, h, pitch;
		int size;
	} buf;
	const int size = (w * 2) * (h * 2) * sizeof(uint32_t);
	if (buf.size < size) {
		free(buf.ptr);
		buf.size = size;
		buf.w = w * 2;
		buf.h = h * 2;
		buf.pitch = buf.w;
		buf.ptr = (uint32_t *)malloc(buf.size);
		if (!buf.ptr) {
			error("Unable to allocate scale4x intermediate buffer");
		}
	}
	scale2x(buf.ptr, buf.pitch, src, srcPitch, w, h);
	scale2x(dst, dstPitch, buf.ptr, buf.pitch, buf.w, buf.h);
}

static void scaleNx(int factor, uint32_t *dst, int dstPitch, const uint32_t *src, int srcPitch, int w, int h) {
	switch (factor) {
	case 2:
		return scale2x(dst, dstPitch, src, srcPitch, w, h);
	case 3:
		return scale3x(dst, dstPitch, src, srcPitch, w, h);
	case 4:
		return scale4x(dst, dstPitch, src, srcPitch, w, h);
	}
}

const Scaler _internalScaler = {
	SCALER_TAG,
	"scaleNx",
	2, 4,
	scaleNx,
};

static DynLib *dynLib;

static const char *kSoSym = "getScaler";

const Scaler *findScaler(const char *name) {
	dynLib = new DynLib(name);
	void *symbol = dynLib->getSymbol(kSoSym);
	if (symbol) {
		typedef const Scaler *(*GetScalerProc)();
		return ((GetScalerProc)symbol)();
	}
	return 0;
}