// Copyright (C) 2021 Harry Godden (hgn) - All Rights Reserved

//#define VG_STEAM
#include "vg/vg.h"

SHADER_DEFINE( shader_tile_colour,

	// VERTEX
	"layout (location=0) in vec2 a_co;"
	"uniform mat3 uPv;"
	"uniform vec2 uOffset;"
	""
	"void main()"
	"{"
		"gl_Position = vec4( uPv * vec3( a_co + uOffset, 1.0 ), 1.0 );"
	"}",
	
	// FRAGMENT
	"out vec4 FragColor;"
	"uniform vec4 uColour;"
	""
	"void main()"
	"{"
		"FragColor = uColour;"
	"}"
	,
	UNIFORMS({ "uPv", "uOffset", "uColour" })
)

m3x3f m_projection;
m3x3f m_view;
m3x3f m_mdl;

#define FLAG_INPUT 0x1
#define FLAG_OUTPUT 0x2
#define FLAG_CANAL 0x4
#define FLAG_WALL 0x8

struct world
{
	struct cell
	{
		u32 state;
	} 
	*data;
	
	struct cell_terminal
	{
		char *conditions;
		int id;
	}
	*io;
	
	u32 w, h;
	
	GLuint tile_vao;
	GLuint tile_vbo;
	
	int selected;
} world = {};

static void map_free(void)
{
	for( int i = 0; i < arrlen( world.io ); i ++ )
		arrfree( world.io[ i ].conditions );
	
	arrfree( world.data );
	arrfree( world.io );
	
	world.w = 0;
	world.h = 0;
	world.data = NULL;
	world.io = NULL;
}

static int map_load( const char *str )
{
	map_free();

	char const *c = str;
	
	// Scan for width
	for(;; world.w ++)
	{
		if( str[world.w] == ';' )
			break;
		else if( !str[world.w] )
		{
			vg_error( "Unexpected EOF when parsing level\n" );
			return 0;
		}
	}
	
	struct cell *row = arraddnptr( world.data, world.w );
	int cx = 0;
	int reg_start = 0, reg_end = 0;
	
	for(;;)
	{
		if( !*c )
			break;
	
		if( *c == ';' )
		{
			c ++;

			// Parse attribs
			if( *c != '\n' )
			{
				while( *c )
				{
					if( reg_start < reg_end )
					{
						if( *c >= 'a' && *c <= 'z' )
						{
							arrpush( world.io[ reg_start ].conditions, *c );
						}
						else
						{
							if( *c == ',' || *c == '\n' )
							{
								reg_start ++;
								
								if( *c == '\n' )
									break;
							}
							else
							{
								vg_error( "Unkown attribute '%c' (row: %u)\n", *c, world.h );
								return 0;
							}
						}
					}
					else
					{
						vg_error( "Too many values to assign (row: %u)\n", world.h );
						return 0;
					}
					
					c ++;
				}
			}
			
			if( reg_start != reg_end )
			{
				vg_error( "Not enough values assigned (row: %u, %u of %u)\n", world.h, reg_start, reg_end );
				return 0;
			}
			
			if( cx != world.w )
			{
				vg_error( "Not enough cells to match previous row definition (row: %u, %u<%u)\n", world.h, cx, world.w );
				return 0;
			}
			
			row = arraddnptr( world.data, world.w );
			cx = 0;
			world.h ++;
			reg_end = reg_start = arrlen( world.io );
		}
		else
		{
			if( cx == world.w )
			{
				vg_error( "Too many cells to match previous row definition (row: %u, %u>%u)\n", world.h, cx, world.w );
				return 0;
			}
			
			// Tile initialization
			// row[ cx ] .. etc
			
			if( *c == '+' || *c == '-' )
			{
				struct cell_terminal term = { .id = cx + world.h*world.w };
				arrpush( world.io, term );
				row[ cx ++ ].state = *c == '+'? FLAG_INPUT: FLAG_OUTPUT;
				reg_end ++;
			}
			else if( *c == '#' )
			{
				row[ cx ++ ].state = FLAG_WALL;
			}
			else
			{
				row[ cx ++ ].state = 0x00;
			}
		}
	
		c ++;
	}
	
	vg_success( "Map loaded! (%u:%u)\n", world.w, world.h );
	return 1;
}

int main( int argc, char *argv[] )
{
	vg_init( argc, argv, "FishLadder" );
}

void vg_register(void)
{
	SHADER_INIT( shader_tile_colour );
}

void vg_start(void)
{
	glGenVertexArrays( 1, &world.tile_vao );
	glGenBuffers( 1, &world.tile_vbo );
	
	float quad_mesh[] =
	{
		0.05f, 0.05f, 0.05f, 0.95f, 0.95f, 0.95f,
		0.05f, 0.05f, 0.95f, 0.95f, 0.95f, 0.05f
	};
	
	glBindVertexArray( world.tile_vao );
	glBindBuffer( GL_ARRAY_BUFFER, world.tile_vbo );
	glBufferData
	(
		GL_ARRAY_BUFFER,
		sizeof( quad_mesh ),
		quad_mesh,
		GL_STATIC_DRAW
	);
	
	glVertexAttribPointer( 0, 2, GL_FLOAT, GL_FALSE, 2 * sizeof(float), (void*)0 );
	glEnableVertexAttribArray( 0 );
	
	VG_CHECK_GL();	
	
	map_load
	( 
		"#############;\n"
		"###-#####-###;aaa,aa\n"
		"##         ##;\n"
		"##         ##;\n"
		"##         ##;\n"
		"##         ##;\n"
		"##         ##;\n"
		"##         ##;\n"
		"###+#####+###;aa,aaa\n"
		"#############;\n"
	);
}

void vg_free(void)
{
	glDeleteVertexArrays( 1, &world.tile_vao );
	glDeleteBuffers( 1, &world.tile_vbo );
	
	map_free();
}

void vg_update(void)
{
	float ratio = (float)vg_window_y / (float)vg_window_x;
	float const size = 9.5f;
	
	v3f origin;
	origin[0] = -0.5f * world.w;
	origin[1] = -0.5f * world.h;
	origin[2] = 0.0f;
	
	m3x3_projection( m_projection, -size, size, size*ratio, -size*ratio );
	m3x3_identity( m_view );
	m3x3_translate( m_view, origin );
	m3x3_mul( m_projection, m_view, vg_pv );
	vg_projection_update();
	
	v2f tile_pos;
	v2_copy( vg_mouse_ws, tile_pos );
	
	int tile_x = floorf( tile_pos[0] );
	int tile_y = floorf( tile_pos[1] );
	
	if( tile_x >= 0 && tile_x < world.w && tile_y >= 0 && tile_y <= world.h )
		world.selected = tile_y * world.h + tile_x;
	else
		world.selected = -1;
}

void vg_render(void)
{
	glViewport( 0,0, vg_window_x, vg_window_y );

	glDisable( GL_DEPTH_TEST );
	glClearColor( 0.01f, 0.01f, 0.01f, 1.0f );
	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
	
	glBindVertexArray( world.tile_vao );
	SHADER_USE( shader_tile_colour );
	glUniformMatrix3fv( SHADER_UNIFORM( shader_tile_colour, "uPv" ), 1, GL_FALSE, (float *)vg_pv );
	
	for( int y = 0; y < world.h; y ++ )
	{
		for( int x = 0; x < world.w; x ++ )
		{
			glUniform2f( SHADER_UNIFORM( shader_tile_colour, "uOffset" ), (float)x, (float)y );
			
			v4f colour;
			
			struct cell *cell = &world.data[y*world.h+x];
			
			if( cell->state & FLAG_WALL ) { v4_copy( (v4f){ 0.4f, 0.4f, 0.4f, 1.0f }, colour ); }
			else if( cell->state & FLAG_CANAL ) { v4_copy( (v4f){ 0.6f, 0.6f, 0.6f, 1.0f }, colour ); }
			else if( cell->state & FLAG_INPUT ) { v4_copy( (v4f){ 0.2f, 0.3f, 0.7f, 1.0f }, colour ); }
			else if( cell->state & FLAG_OUTPUT ) { v4_copy( (v4f){ 0.2f, 0.7f, 0.3f, 1.0f }, colour ); }
			else v4_copy( (v4f){ 1.0f, 0.0f, 0.0f, 1.0f }, colour );
			
			if( world.selected == y*world.h + x )
				v3_muls( colour, sinf( vg_time )*0.25f + 0.5f, colour );
				
			glUniform4fv( SHADER_UNIFORM( shader_tile_colour, "uColour" ), 1, colour );
			
			glDrawArrays( GL_TRIANGLES, 0, 6 );
		}
	}
}

void vg_ui(void){}