#include <thin3d/thin3d.h>

#include "image/zim_load.h"
#include "image/png_load.h"

static const char * const glsl_fsTexCol =
"varying vec4 oColor0;\n"
"varying vec2 oTexCoord0;\n"
"uniform sampler2D Sampler0;\n"
"void main() { gl_FragColor = oColor0 * texture2D(Sampler0, oTexCoord0); }\n";

static const char * const hlslFsTexCol =
"struct PS_INPUT { float4 color : COLOR0; float2 uv : TEXCOORD0; };\n"
"sampler2D tex0;\n"
"float4 main(PS_INPUT input) : COLOR0 {\n"
"  return input.color * tex2D(tex0, input.uv);\n"
"}\n";

static const char * const glsl_fsCol =
"varying vec4 oColor0;\n"
"uniform sampler2D Sampler0;\n"
"void main() { gl_FragColor = oColor0; }\n";

static const char * const hlslFsCol =
"struct PS_INPUT { float4 color : COLOR0; };\n"
"float4 main(PS_INPUT input) : COLOR0 {\n"
"  return input.color;\n"
"}\n";

static const char * const glsl_vsCol =
"attribute vec3 Position;\n"
"attribute vec4 Color0;\n"
"varying vec4 oColor0;\n"
"uniform mat4 WorldViewProj;\n"
"void main() {\n"
"	gl_Position = WorldViewProj * vec4(Position, 1.0);\n"
"	oColor0 = Color0;\n"
"}";

static const char * const hlslVsCol =
"struct VS_INPUT { float3 Position : POSITION; float4 Color0 : COLOR0; };\n"
"struct VS_OUTPUT { float4 Position : POSITION; float4 Color0 : COLOR0; };\n"
"float4x4 WorldViewProj;\n"
"VS_OUTPUT main(VS_INPUT input) {\n"
"  VS_OUTPUT output;\n"
"  output.Position = mul(float4(input.Position, 1.0), WorldViewProj);\n"
"  output.Color0 = input.Color0;\n"
"  return output;\n"
"}\n";

static const char * const glsl_vsTexCol =
"attribute vec3 Position;\n"
"attribute vec4 Color0;\n"
"attribute vec2 TexCoord0;\n"
"varying vec4 oColor0;\n"
"varying vec2 oTexCoord0;\n"
"uniform mat4 WorldViewProj;\n"
"void main() {\n"
"	gl_Position = WorldViewProj * vec4(Position, 1.0);\n"
"	oColor0 = Color0;\n"
" oTexCoord0 = TexCoord0; \n"
"}\n";

static const char * const hlslVsTexCol =
"struct VS_INPUT { float3 Position : POSITION; float2 Texcoord0 : TEXCOORD0; float4 Color0 : COLOR0; };\n"
"struct VS_OUTPUT { float4 Position : POSITION; float2 Texcoord0 : TEXCOORD0; float4 Color0 : COLOR0; };\n"
"float4x4 WorldViewProj;\n"
"VS_OUTPUT main(VS_INPUT input) {\n"
"  VS_OUTPUT output;\n"
"  output.Position = mul(float4(input.Position, 1.0), WorldViewProj);\n"
"  output.Texcoord0 = input.Texcoord0;\n"
"  output.Color0 = input.Color0;\n"
"  return output;\n"
"}\n";

void Thin3DContext::CreatePresets() {
	// Build prebuilt objects
	T3DBlendStateDesc off = { false };
	T3DBlendStateDesc additive = { true, T3DBlendEquation::ADD, T3DBlendFactor::ONE, T3DBlendFactor::ONE, T3DBlendEquation::ADD, T3DBlendFactor::ONE, T3DBlendFactor::ZERO };
	T3DBlendStateDesc standard_alpha = { true, T3DBlendEquation::ADD, T3DBlendFactor::SRC_ALPHA, T3DBlendFactor::ONE_MINUS_SRC_ALPHA, T3DBlendEquation::ADD, T3DBlendFactor::ONE, T3DBlendFactor::ZERO };
	T3DBlendStateDesc premul_alpha = { true, T3DBlendEquation::ADD, T3DBlendFactor::ONE, T3DBlendFactor::ONE_MINUS_SRC_ALPHA, T3DBlendEquation::ADD, T3DBlendFactor::ONE, T3DBlendFactor::ZERO };

	bsPresets_[BS_OFF] = CreateBlendState(off);
	bsPresets_[BS_ADDITIVE] = CreateBlendState(additive);
	bsPresets_[BS_STANDARD_ALPHA] = CreateBlendState(standard_alpha);
	bsPresets_[BS_PREMUL_ALPHA] = CreateBlendState(premul_alpha);

	vsPresets_[VS_TEXTURE_COLOR_2D] = CreateVertexShader(glsl_vsTexCol, hlslVsTexCol);
	vsPresets_[VS_COLOR_2D] = CreateVertexShader(glsl_vsCol, hlslVsCol);

	fsPresets_[FS_TEXTURE_COLOR_2D] = CreateFragmentShader(glsl_fsTexCol, hlslFsTexCol);
	fsPresets_[FS_COLOR_2D] = CreateFragmentShader(glsl_fsCol, hlslFsCol);

	ssPresets_[SS_TEXTURE_COLOR_2D] = CreateShaderSet(vsPresets_[VS_TEXTURE_COLOR_2D], fsPresets_[FS_TEXTURE_COLOR_2D]);
	ssPresets_[SS_COLOR_2D] = CreateShaderSet(vsPresets_[VS_COLOR_2D], fsPresets_[FS_COLOR_2D]);
}

Thin3DContext::~Thin3DContext() {
	for (int i = 0; i < VS_MAX_PRESET; i++) {
		vsPresets_[i]->Release();
	}
	for (int i = 0; i < FS_MAX_PRESET; i++) {
		fsPresets_[i]->Release();
	}
	for (int i = 0; i < BS_MAX_PRESET; i++) {
		bsPresets_[i]->Release();
	}
	for (int i = 0; i < SS_MAX_PRESET; i++) {
		ssPresets_[i]->Release();
	}
}

static T3DImageFormat ZimToT3DFormat(int zim) {
	switch (zim) {
	case ZIM_ETC1: return T3DImageFormat::ETC1;
	case ZIM_RGBA8888: return T3DImageFormat::RGBA8888;
	case ZIM_LUMINANCE: return T3DImageFormat::LUMINANCE;
	default: return T3DImageFormat::RGBA8888;
	}
}

Thin3DTexture *Thin3DContext::CreateTextureFromFile(const char *filename, T3DFileType type) {
	int width[16], height[16], flags;
	uint8_t *image[16] = { nullptr };

	int num_levels = LoadZIM(filename, width, height, &flags, image);
	if (num_levels == 0) {
		return NULL;
	}

	T3DImageFormat fmt = ZimToT3DFormat(flags & ZIM_FORMAT_MASK);

	Thin3DTexture *tex = CreateTexture(LINEAR2D, fmt, width[0], height[0], 1, num_levels);
	for (int i = 0; i < num_levels; i++) {
		tex->SetImageData(0, 0, 0, width[i], height[i], 1, i, width[i] * 4, image[i]);
		free(image[i]);
	}
	return tex;
}

Thin3DTexture *Thin3DContext::CreateTextureFromFileData(const char *data, int size, T3DFileType type) {
	int width[16], height[16], zim_flags = 0;
	uint8_t *image[16] = { nullptr };

	int num_levels = 0;
	T3DImageFormat fmt;

	switch (type) {
	case ZIM:
		num_levels = LoadZIMPtr((const uint8_t *)data, size, width, height, &zim_flags, image);
		fmt = ZimToT3DFormat(zim_flags & ZIM_FORMAT_MASK);
		break;

	case PNG:
		if (1 != pngLoadPtr((const unsigned char *)data, size, &width[0], &height[0], &image[0], false)) {
			return false;
		}
		num_levels = 1;
		fmt = RGBA8888;
		break;
	}

	if (num_levels == 0) {
		return NULL;
	}

	Thin3DTexture *tex = CreateTexture(LINEAR2D, fmt, width[0], height[0], 1, num_levels);
	for (int i = 0; i < num_levels; i++) {
		tex->SetImageData(0, 0, 0, width[i], height[i], 1, i, width[i] * 4, image[i]);
		free(image[i]);
	}

	tex->Finalize(zim_flags);
	return tex;
}