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

_ SDL_Window*win;
_ SDL_GLContext ctx;
_ U32 win_w=1280,win_h=720;
_ IM C solid_vert[]="#version 330 core\nlayout(location=0)in vec3 pos;void main(){gl_Position=vec4(pos.x,pos.y,pos.z,1.0);}";
_ IM C solid_frag[]="#version 330 core\nout vec4 Colour;void main(){Colour=vec4(1.0, 0.5, 0.2, 1.0);}";
_ U32 solid_shader;
_ V on_err(IM C*d){die("Could not %s: %s\n",d,SDL_GetError());}

_ V q_init(V);
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|SDL_WINDOW_RESIZABLE),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);
  q_init(),
  solid_shader=graph_shader_create(solid_vert,solid_frag);
  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_events(V){SDL_Event ev;U32 t;WH(SDL_PollEvent(&ev),t=ev.type;
  Q(SDL_QUIT==t,exit(0))OR
  Q(SDL_WINDOWEVENT==t,SDL_WindowEvent ew=ev.window;
    Q(SDL_WINDOWEVENT_RESIZED==ew.event
    ||SDL_WINDOWEVENT_SIZE_CHANGED==ew.event,glViewport(0,0,ew.data1,ew.data2))))}

V graph_deinit(V){SDL_GL_DeleteContext(ctx),SDL_DestroyWindow(win),SDL_Quit();}
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);}

_ U32 q_vao,q_vbo,q_ebo;
_ V q_init(V){
  _ IM F32 verts[]={
     0.5, 0.5,0.0,
     0.5,-0.5,0.0,
    -0.5,-0.5,0.0,
    -0.5, 0.5,0.0};
  _ IM U32 indxs[]={0,1,3,1,2,3};
  glGenVertexArrays(1,&q_vao),glGenBuffers(1,&q_vbo),glGenBuffers(1,&q_ebo);
  glBindVertexArray(q_vao),
  glBindBuffer(GL_ARRAY_BUFFER,q_vbo),
  glBufferData(GL_ARRAY_BUFFER,SZ verts,verts,GL_STATIC_DRAW),
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,q_ebo),
  glBufferData(GL_ELEMENT_ARRAY_BUFFER,SZ indxs,indxs,GL_STATIC_DRAW);
  glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,3*SZ verts[0],0),
  glEnableVertexAttribArray(0),
  glBindVertexArray(0);}
V graph_quad(V){
  glUseProgram(solid_shader),
  glBindVertexArray(q_vao),
  glDrawElements(GL_TRIANGLES,6,GL_UNSIGNED_INT,0),
  glBindVertexArray(0);}

U32 graph_shader_create(IM C*vert,IM C*frag){I ok;C info[512];U32 v,f,p;
  v=glCreateShader(GL_VERTEX_SHADER),  glShaderSource(v,1,&vert,0),glCompileShader(v),
  glGetShaderiv(v,GL_COMPILE_STATUS,&ok);N(ok,glGetShaderInfoLog(v,512,0,info),die("error compiling vert: %s",info))
  f=glCreateShader(GL_FRAGMENT_SHADER),glShaderSource(f,1,&frag,0),glCompileShader(f),
  glGetShaderiv(f,GL_COMPILE_STATUS,&ok);N(ok,glGetShaderInfoLog(f,512,0,info),die("error compiling frag: %s",info))
  p=glCreateProgram(),glAttachShader(p,v),glAttachShader(p,f),glLinkProgram(p);
  glGetProgramiv(p,GL_LINK_STATUS,&ok); N(ok,glGetProgramInfoLog(p,512,0,info),die("error linking shader: %s",info))
  glDeleteShader(v),glDeleteShader(f);
  R p;}