#include<stdio.h>
#include<glad/glad.h>
#define SDL_MAIN_HANDLED
#include<SDL.h>
#include"mino.h"
#include"graph.h"

_ SDL_Window*win;
_ U32 win_w=1280;
_ U32 win_h=720;
_ SDL_GLContext ctx;

_ V on_err(IM C*d){die("Could not %s: %s\n",d,SDL_GetError());}

V graph_init(V){SDL_version sdl_vh,sdl_vl;
  Q(SDL_Init(SDL_INIT_VIDEO),on_err("init sdl2"))
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION,3),
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION,3),
  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,SDL_GL_CONTEXT_PROFILE_CORE),
  SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1);
  N(win=SDL_CreateWindow("mino",SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,win_w,win_h,SDL_WINDOW_OPENGL),on_err("create window"))
  N(ctx=SDL_GL_CreateContext(win),on_err("create OpenGL context"))
  N(gladLoadGLLoader(SDL_GL_GetProcAddress),on_err("load GL"))
  SDL_GL_SetSwapInterval(1);

  SDL_VERSION(&sdl_vh)SDL_GetVersion(&sdl_vl);
  fprintf(stderr,
    "Graphics initialization successful!\n"
    "\tSDL Version:     %d.%d.%d (built against)\n"
    "\tSDL Version:     %d.%d.%d (linked against)\n"
    "\tOpenGL Version:  %s\n"
    "\tOpenGL Vendor:   %s\n"
    "\tOpenGL Renderer: %s\n",
    sdl_vh.major,sdl_vh.minor,sdl_vh.patch,
    sdl_vl.major,sdl_vl.minor,sdl_vl.patch,
    glGetString(GL_VERSION),glGetString(GL_VENDOR),glGetString(GL_RENDERER));}

V graph_deinit(V){SDL_GL_DeleteContext(ctx),SDL_DestroyWindow(win),SDL_Quit();}
V graph_events(V){SDL_Event ev;WH(SDL_PollEvent(&ev),Q(SDL_QUIT==ev.type,exit(0)))}
V graph_before(V){glClearColor(1.0,0.75,0.8,1.0),glClear(GL_COLOR_BUFFER_BIT);}
V graph_after(V){SDL_GL_SwapWindow(win);}

V graph_triangle(V){
  IM C*vert_shader_src="#version 330 core\n"
    "layout(location=0)in vec3 pos;void main(){gl_Position=vec4(pos.x,pos.y,pos.z,1.0);}";
  U32 vert_shader=glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vert_shader,1,&vert_shader_src,NULL),glCompileShader(vert_shader);
  I success;
  C info_log[512];
  glGetShaderiv(vert_shader,GL_COMPILE_STATUS,&success);
  N(success,die("error compiling vert shader"))

  IM C*frag_shader_src = "#version 330 core\n"
    "out vec4 Colour;void main(){Colour=vec4(1.0, 0.5, 0.2, 1.0);}";
  U32 frag_shader=glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(frag_shader,1,&frag_shader_src,NULL),glCompileShader(frag_shader);
  glGetShaderiv(vert_shader,GL_COMPILE_STATUS,&success);
  N(success,die("error compiling frag shader"))

  U32 shader_program=glCreateProgram();
  glAttachShader(shader_program,vert_shader),glAttachShader(shader_program,frag_shader),
  glLinkProgram(shader_program);//glDeleteShader(vert_shader),glDeleteShader(frag_shader);
  glGetProgramiv(shader_program,GL_LINK_STATUS,&success);
  N(success,glGetProgramInfoLog(shader_program,512,0,info_log),die("error linking: %s"))

  IM F32 verts[]={
    -0.5,-0.5,0.0,
     0.5,-0.5,0.0,
     0.0, 0.5,0.0};
  U32 vbo,vao;
  glGenBuffers(1,&vbo),       glBindBuffer(GL_ARRAY_BUFFER,vbo),
  glGenVertexArrays(1,&vao),  glBindVertexArray(vao);
  glBufferData(GL_ARRAY_BUFFER,SZ verts,verts,GL_STATIC_DRAW),
  glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,3*SZ verts[0],0),
  glEnableVertexAttribArray(0),glUseProgram(shader_program),
  glBindVertexArray(vao),glDrawArrays(GL_TRIANGLES,0,3);}