#include <framebuffer.h>

#include <mailbox.h>

#include <stddef.h>
#include <stdint.h>

#define WIDTH     640
#define HEIGHT    480
#define DEPTH      32
#define ALIGNMENT  16 // Framebuffer byte alignment.

typedef struct Framebuffer {
  volatile void* pixels;
  size_t         size;
} Framebuffer;

static Framebuffer framebuffer = {};

bool framebuffer_init(uint32_t* error) {
  MAIL_T uint32_t ConfigureScreen[20] = {
    80, // Size in bytes, aligned to MAIL_ALIGN.
    MAILBOX_REQUEST,
    TAG_FRAMEBUFFER_SET_PHYSICAL_SCREEN_SIZE, 8, MAILBOX_REQUEST, WIDTH, HEIGHT,
    TAG_FRAMEBUFFER_SET_VIRTUAL_SCREEN_SIZE,  8, MAILBOX_REQUEST, WIDTH, HEIGHT,
    TAG_FRAMEBUFFER_SET_DEPTH,                4, MAILBOX_REQUEST, DEPTH,
    TAG_END,
    0, 0, 0 // Padding.
  };
  mbox_write(PROPERTY_CHANNEL, ConfigureScreen);
  const Mail* response = mbox_read(PROPERTY_CHANNEL);
  if (response->code != MAILBOX_SUCCESS) {
    goto end;
  }
  
  MAIL_T uint32_t InitFramebuffer[8] = {
    32, // Size in bytes, aligned to MAIL_ALIGN.
    MAILBOX_REQUEST,
    TAG_FRAMEBUFFER_ALLOCATE, 8, MAILBOX_REQUEST, ALIGNMENT, 0,
    TAG_END
  };
  mbox_write(PROPERTY_CHANNEL, InitFramebuffer);
  response = mbox_read(PROPERTY_CHANNEL);
  if (response->code != MAILBOX_SUCCESS) {
    goto end;
  }
  
  // The input mail is overwritten with the response.
  //   u32 fb base address
  //   u32 fb size
  framebuffer.pixels = (void*)(uintptr_t)InitFramebuffer[5];
  framebuffer.size   = InitFramebuffer[6];
  
end:
  *error = response->code;
  return response->code == MAILBOX_SUCCESS;
}