#!/usr/bin/env python3
"""
draw_12_rects_and_send.py

* 800 × 600 framebuffer, 32‑bit ARGB (A,R,G,B each 1 byte)
* 12 rectangles, aspect ratio width : height = 1 : 12  (tall, upright)
* rectangles are placed side‑by‑side, centred in the image
* the complete framebuffer is sent over a TCP connection to
  a server listening on localhost:12345
"""

import socket
import sys

# ----------------------------------------------------------------------
# Frame‑buffer configuration
# ----------------------------------------------------------------------
FB_WIDTH  = 800                # horizontal pixels
FB_HEIGHT = 600                # vertical   pixels
BPP       = 4                  # bytes per pixel (A,R,G,B)

# ----------------------------------------------------------------------
# Geometry of the 12 rectangles
# ----------------------------------------------------------------------
# Height of a rectangle must fill the whole image (600 px)
# width = height / 12  →  600 / 12 = 50 px
RECT_HEIGHT = FB_HEIGHT // 2
RECT_WIDTH  = RECT_HEIGHT // 12          # 50
SPACING = 20

TOTAL_RECT_W = (11 * SPACING) + (RECT_WIDTH * 12)           # 600
X0_START    = (FB_WIDTH - TOTAL_RECT_W) // 2   # centre the strip

# ----------------------------------------------------------------------
# Helper – write a pixel into the bytearray (no bounds check for speed)
# ----------------------------------------------------------------------
def set_pixel(buf: bytearray, x: int, y: int, color: tuple):
    """Write an ARGB pixel at (x,y).

    `color` is a 4‑tuple (A,R,G,B) with each component 0‑255.
    """
    offset = (y * FB_WIDTH + x) * BPP
    buf[offset:offset+4] = bytes(color)      # A,R,G,B order


# ----------------------------------------------------------------------
# Build the framebuffer
# ----------------------------------------------------------------------
def build_framebuffer() -> bytearray:
    """Create an ARGB buffer, fill it black and draw the 12 rectangles."""
    fb = bytearray(FB_WIDTH * FB_HEIGHT * BPP)

    # ------------------------------------------------------------------
    # 1) background = solid black, fully opaque
    # ------------------------------------------------------------------
    bg_color = (255, 0, 0, 0)                 # A,R,G,B
    # Fill the whole buffer in one go (faster than per‑pixel loop)
    fb[:] = bg_color * (FB_WIDTH * FB_HEIGHT)

    # ------------------------------------------------------------------
    # 2) draw the 12 rectangles
    # ------------------------------------------------------------------
    for idx in range(12):
        rect_color = (255, 255, 255, 255)          # opaque

        x_start = X0_START + idx * (RECT_WIDTH + SPACING)
        x_end   = x_start + RECT_WIDTH            # exclusive

        for y in range(FB_HEIGHT):
            # slice‑assignment is faster than per‑pixel calls
            row_offset = (y * FB_WIDTH + x_start) * BPP
            fb[row_offset:row_offset + RECT_WIDTH * BPP] = rect_color * RECT_WIDTH

    return fb


# ----------------------------------------------------------------------
# Send the buffer to the TCP server
# ----------------------------------------------------------------------
def send_framebuffer(buf: bytearray, host: str = "127.0.0.1", port: int = 12345):
    """Open a TCP socket, connect, and stream the whole framebuffer."""
    try:
        with socket.create_connection((host, port), timeout=5) as sock:
            # Optional: prefix the payload with its length (big‑endian uint32)
            length_prefix = len(buf).to_bytes(4, byteorder="big")
            sock.sendall(length_prefix + buf)
            print(f"Sent {len(buf)} bytes to {host}:{port}")
    except Exception as exc:
        print(f"Could not send framebuffer: {exc}", file=sys.stderr)


# ----------------------------------------------------------------------
# Main entry point
# ----------------------------------------------------------------------
def main():
    fb = build_framebuffer()
    send_framebuffer(fb)


if __name__ == "__main__":
    main()