import OpenGL.GL as gl

class ShaderManager:
 def __init__(self):
  self.program = None
  self.bg_program = None
  self.pp_program = None
  self.blur_program = None
  self.capture_fbo = None
  self.capture_tex = None
  self.fbo_width = 0
  self.fbo_height = 0

 def setup_capture_fbo(self, width, height):
  if self.capture_fbo is not None:
   gl.glDeleteFramebuffers(1, [self.capture_fbo])
  if self.capture_tex is not None:
   gl.glDeleteTextures(1, [self.capture_tex])
  self.capture_fbo = gl.glGenFramebuffers(1)
  self.capture_tex = gl.glGenTextures(1)
  gl.glBindTexture(gl.GL_TEXTURE_2D, self.capture_tex)
  gl.glTexImage2D(gl.GL_TEXTURE_2D, 0, gl.GL_RGBA, width, height, 0, gl.GL_RGBA, gl.GL_UNSIGNED_BYTE, None)
  gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MIN_FILTER, gl.GL_LINEAR)
  gl.glTexParameteri(gl.GL_TEXTURE_2D, gl.GL_TEXTURE_MAG_FILTER, gl.GL_LINEAR)
  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, self.capture_fbo)
  gl.glFramebufferTexture2D(gl.GL_FRAMEBUFFER, gl.GL_COLOR_ATTACHMENT0, gl.GL_TEXTURE_2D, self.capture_tex, 0)
  if gl.glCheckFramebufferStatus(gl.GL_FRAMEBUFFER) != gl.GL_FRAMEBUFFER_COMPLETE:
   raise RuntimeError("Framebuffer not complete")
  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, 0)
  self.fbo_width = width
  self.fbo_height = height

 def capture_begin(self, width, height):
  if self.capture_fbo is None or self.fbo_width != width or self.fbo_height != height:
   self.setup_capture_fbo(width, height)
  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, self.capture_fbo)
  gl.glViewport(0, 0, width, height)

 def capture_end(self):
  gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, 0)

 def compile_shader(self, vertex_src: str, fragment_src: str) -> int:
  program = gl.glCreateProgram()
  
  def _compile(src, shader_type):
   shader = gl.glCreateShader(shader_type)
   gl.glShaderSource(shader, src)
   gl.glCompileShader(shader)
   
   if not gl.glGetShaderiv(shader, gl.GL_COMPILE_STATUS):
    info_log = gl.glGetShaderInfoLog(shader)
    if hasattr(info_log, "decode"):
     info_log = info_log.decode()
    raise RuntimeError(f"Shader compilation failed: {info_log}")
   return shader

  vert_shader = _compile(vertex_src, gl.GL_VERTEX_SHADER)
  frag_shader = _compile(fragment_src, gl.GL_FRAGMENT_SHADER)
  
  gl.glAttachShader(program, vert_shader)
  gl.glAttachShader(program, frag_shader)
  gl.glLinkProgram(program)
  
  if not gl.glGetProgramiv(program, gl.GL_LINK_STATUS):
   info_log = gl.glGetProgramInfoLog(program)
   if hasattr(info_log, "decode"):
    info_log = info_log.decode()
   raise RuntimeError(f"Program linking failed: {info_log}")
  
  gl.glDeleteShader(vert_shader)
  gl.glDeleteShader(frag_shader)
  
  self.program = program
  return program

 def update_uniforms(self, uniforms: dict):
  if self.program is None:
   return
  
  for name, value in uniforms.items():
   loc = gl.glGetUniformLocation(self.program, name)
   if loc == -1:
    continue
   
   if isinstance(value, float):
    gl.glUniform1f(loc, value)
   elif isinstance(value, int):
    gl.glUniform1i(loc, value)
   elif isinstance(value, (list, tuple)):
    if len(value) == 2:
     gl.glUniform2f(loc, value[0], value[1])
    elif len(value) == 3:
     gl.glUniform3f(loc, value[0], value[1], value[2])
    elif len(value) == 4:
     gl.glUniform4f(loc, value[0], value[1], value[2], value[3])

 def setup_background_shader(self):
  vertex_src = """
#version 330 core
const vec2 positions[4] = vec2[](
 vec2(-1.0, -1.0),
 vec2( 1.0, -1.0),
 vec2(-1.0,  1.0),
 vec2( 1.0,  1.0)
);
void main() {
 gl_Position = vec4(positions[gl_VertexID], 0.0, 1.0);
}
"""
  fragment_src = """
#version 330 core
uniform float u_time;
uniform vec2 u_resolution;
out vec4 FragColor;
void main() {
 vec2 uv = gl_FragCoord.xy / u_resolution.xy;
 vec3 col = 0.5 + 0.5 * cos(u_time + uv.xyx + vec3(0, 2, 4));
 FragColor = vec4(col, 1.0);
}
"""
  self.bg_program = self.compile_shader(vertex_src, fragment_src)

 def render_background(self, width, height, time):
  if not self.bg_program:
   return
  gl.glUseProgram(self.bg_program)
  u_time_loc = gl.glGetUniformLocation(self.bg_program, "u_time")
  if u_time_loc != -1:
   gl.glUniform1f(u_time_loc, float(time))
  u_res_loc = gl.glGetUniformLocation(self.bg_program, "u_resolution")
  if u_res_loc != -1:
   gl.glUniform2f(u_res_loc, float(width), float(height))
  gl.glDrawArrays(gl.GL_TRIANGLE_STRIP, 0, 4)
  gl.glUseProgram(0)

 def setup_post_process_shader(self):
  vertex_src = """
#version 330 core
const vec2 positions[4] = vec2[](
 vec2(-1.0, -1.0),
 vec2( 1.0, -1.0),
 vec2(-1.0,  1.0),
 vec2( 1.0,  1.0)
);
const vec2 uvs[4] = vec2[](
 vec2(0.0, 0.0),
 vec2(1.0, 0.0),
 vec2(0.0, 1.0),
 vec2(1.0, 1.0)
);
out vec2 v_uv;
void main() {
 gl_Position = vec4(positions[gl_VertexID], 0.0, 1.0);
 v_uv = uvs[gl_VertexID];
}
"""
  fragment_src = """
#version 330 core
in vec2 v_uv;
uniform sampler2D u_texture;
uniform float u_time;
out vec4 FragColor;
void main() {
 vec4 color = texture(u_texture, v_uv);
 float scanline = sin(v_uv.y * 800.0 + u_time * 2.0) * 0.04;
 color.rgb -= scanline;
 FragColor = color;
}
"""
  self.pp_program = self.compile_shader(vertex_src, fragment_src)

 def render_post_process(self, texture_id, width, height, time):
  if not self.pp_program:
   return
  gl.glUseProgram(self.pp_program)
  gl.glActiveTexture(gl.GL_TEXTURE0)
  gl.glBindTexture(gl.GL_TEXTURE_2D, texture_id)
  u_tex_loc = gl.glGetUniformLocation(self.pp_program, "u_texture")
  if u_tex_loc != -1:
   gl.glUniform1i(u_tex_loc, 0)
  u_time_loc = gl.glGetUniformLocation(self.pp_program, "u_time")
  if u_time_loc != -1:
   gl.glUniform1f(u_time_loc, float(time))
  gl.glDrawArrays(gl.GL_TRIANGLE_STRIP, 0, 4)
  gl.glBindTexture(gl.GL_TEXTURE_2D, 0)
  gl.glUseProgram(0)

 def setup_frosted_glass_shader(self):
  vertex_src = """
#version 330 core
const vec2 positions[4] = vec2[](
 vec2(-1.0, -1.0),
 vec2( 1.0, -1.0),
 vec2(-1.0,  1.0),
 vec2( 1.0,  1.0)
);
const vec2 uvs[4] = vec2[](
 vec2(0.0, 0.0),
 vec2(1.0, 0.0),
 vec2(0.0, 1.0),
 vec2(1.0, 1.0)
);
out vec2 v_uv;
void main() {
 gl_Position = vec4(positions[gl_VertexID], 0.0, 1.0);
 v_uv = uvs[gl_VertexID];
}
"""
  fragment_src = """
#version 330 core
in vec2 v_uv;
uniform sampler2D u_texture;
uniform float u_blur_radius;
uniform float u_tint_intensity;
uniform float u_opacity;
out vec4 FragColor;
void main() {
 vec2 res = vec2(textureSize(u_texture, 0));
 vec2 offset = u_blur_radius / res;
 vec4 sum = vec4(0.0);
 sum += texture(u_texture, v_uv + vec2(-offset.x, -offset.y)) * 0.0625;
 sum += texture(u_texture, v_uv + vec2(0.0, -offset.y)) * 0.125;
 sum += texture(u_texture, v_uv + vec2(offset.x, -offset.y)) * 0.0625;
 sum += texture(u_texture, v_uv + vec2(-offset.x, 0.0)) * 0.125;
 sum += texture(u_texture, v_uv + vec2(0.0, 0.0)) * 0.25;
 sum += texture(u_texture, v_uv + vec2(offset.x, 0.0)) * 0.125;
 sum += texture(u_texture, v_uv + vec2(-offset.x, offset.y)) * 0.0625;
 sum += texture(u_texture, v_uv + vec2(0.0, offset.y)) * 0.125;
 sum += texture(u_texture, v_uv + vec2(offset.x, offset.y)) * 0.0625;
 vec3 tinted = mix(sum.rgb, vec3(1.0), u_tint_intensity);
 FragColor = vec4(tinted, sum.a * u_opacity);
}
"""
  self.blur_program = self.compile_shader(vertex_src, fragment_src)