#include <stdbool.h>
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <lua.h>
#include <lauxlib.h>
#include "util/util.h"

int gl_create_shader(lua_State *L);
int gl_shader_set_source(lua_State *L);
int gl_shader_compile(lua_State *L);
int gl_shader_delete(lua_State *L);

int gl_program_create(lua_State *L);
int gl_program_attach_shader(lua_State *L);
int gl_program_link(lua_State *L);
int gl_program_use(lua_State *L);

int gl_uniform_get_location(lua_State *L);
int gl_uniform_1i(lua_State *L);
int gl_uniform_1f(lua_State *L);
int gl_uniform_3f(lua_State *L);
int gl_uniform_4f(lua_State *L);

int gl_uniform_matrix_4fv(lua_State *L);


void setup_shader(lua_State *L, int gl_index)
{
	struct honey_tbl_t tbl[] = {
		/* functions */
		H_FUNC("CreateShader", gl_create_shader),
		H_FUNC("ShaderSource", gl_shader_set_source),
		H_FUNC("CompileShader", gl_shader_compile),
		H_FUNC("DeleteShader", gl_shader_delete),

		H_FUNC("CreateProgram", gl_program_create),
		H_FUNC("AttachShader", gl_program_attach_shader),
		H_FUNC("LinkProgram", gl_program_link),
		H_FUNC("UseProgram", gl_program_use),

		H_FUNC("GetUniformLocation", gl_uniform_get_location),
		H_FUNC("Uniform1i", gl_uniform_1i),
		H_FUNC("Uniform1f", gl_uniform_1i),
		H_FUNC("Uniform3f", gl_uniform_1i),
		H_FUNC("Uniform4f", gl_uniform_4f),

		H_FUNC("UniformMatrix4fv", gl_uniform_matrix_4fv),

		/******** enums ********/
		/* shader types */
		H_INT("VERTEX_SHADER", GL_VERTEX_SHADER),
		H_INT("FRAGMENT_SHADER", GL_FRAGMENT_SHADER),

		H_END
	};
	create_table(L, tbl);
	append_table(L, gl_index, lua_gettop(L));
	lua_pop(L, 1);
}


int gl_create_shader(lua_State *L)
{
	lua_Integer type = luaL_checkinteger(L, 1);
	lua_Integer shader = glCreateShader(type);
	lua_pushinteger(L, shader);
	return 1;
}


int gl_shader_set_source(lua_State *L)
{
	lua_Integer shader = luaL_checkinteger(L, 1);
	const char *code = luaL_checkstring(L, 2);
	glShaderSource(shader, 1, (const GLchar * const*)&code, NULL);
	return 0;
}


int gl_shader_compile(lua_State *L)
{
	lua_Integer shader = luaL_checkinteger(L, 1);
	glCompileShader(shader);
	int success; char log[1024];
	glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
	if (!success) {
		glGetShaderInfoLog(shader, 1024, NULL, log);
		luaL_error(L, "shader compilation failed: %s", log);
	}
	return 0;
}


int gl_shader_delete(lua_State *L)
{
	lua_Integer shader = luaL_checkinteger(L, 1);
	glDeleteShader(shader);
	return 0;
}


int gl_program_create(lua_State *L)
{
	lua_Integer program = glCreateProgram();
	lua_pushinteger(L, program);
	return 1;
}


int gl_program_attach_shader(lua_State *L)
{
	lua_Integer program, shader;
	program = luaL_checkinteger(L, 1);
	shader = luaL_checkinteger(L, 2);
	glAttachShader(program, shader);
	return 0;
}


int gl_program_link(lua_State *L)
{
	lua_Integer program = luaL_checkinteger(L, 1);
	glLinkProgram(program);
	int success; char log[1024];
	glGetProgramiv(program, GL_LINK_STATUS, &success);
	if (!success) {
		glGetProgramInfoLog(program, 1024, NULL, log);
		luaL_error(L, "shader linking failed: %s", log);
	}
	return 0;
}


int gl_program_use(lua_State *L)
{
	lua_Integer program = luaL_checkinteger(L, 1);
	glUseProgram(program);
	return 0;
}


int gl_uniform_get_location(lua_State *L)
{
	lua_Integer program = luaL_checkinteger(L, 1);
	const char *name = luaL_checkstring(L, 2);
	int location = glGetUniformLocation(program, (const GLchar*)name);
	lua_pushinteger(L, location);
	return 1;
}


int gl_uniform_1i(lua_State *L)
{
	lua_Integer location, v0;
	location = luaL_checkinteger(L, 1);
	v0 = luaL_checkinteger(L, 2);
	glUniform1i(location, v0);
	return 0;
}


int gl_uniform_1f(lua_State *L)
{
	int location = luaL_checkinteger(L, 1);
	double value = luaL_checknumber(L, 2);
	glUniform1f(location, value);
	return 0;
}


int gl_uniform_3f(lua_State *L)
{
	int location = luaL_checkinteger(L, 1);
	double v0 = luaL_checknumber(L, 2);
	double v1 = luaL_checknumber(L, 3);
	double v2 = luaL_checknumber(L, 4);
	glUniform3f(location, v0, v1, v2);
	return 0;
}


int gl_uniform_4f(lua_State *L)
{
	lua_Integer location = luaL_checkinteger(L, 1);
	lua_Number v0 = luaL_checknumber(L, 2);
	lua_Number v1 = luaL_checknumber(L, 3);
	lua_Number v2 = luaL_checknumber(L, 4);
	lua_Number v3 = luaL_checknumber(L, 5);
	glUniform4f(location, v0, v1, v2, v3);
	return 0;
}


int gl_uniform_matrix_4fv(lua_State *L)
{
	lua_Integer location = luaL_checkinteger(L, 1);
	bool transpose = lua_toboolean(L, 2);
	float *value = lua_touserdata(L, 3);
	glUniformMatrix4fv(location, 1, transpose, value);
	return 0;
}