"""Media made from a seed, so two runs upload the same bytes: identicon PNGs, a sine-tone WAV, and the committed
media/tiny.mp4 and media/tiny.ogg (made once with ffmpeg; the command is in media/SOURCES.md)."""
import hashlib
import math
import os
import struct
import zlib

HERE = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))


def png(seed, size=96, cells=6):
	"""A symmetric identicon: a colour and a mirrored grid from the SHA-256 of the seed."""
	h = hashlib.sha256(str(seed).encode()).digest()
	fg = (h[0], h[1], h[2])
	bg = (240, 240, 236) if sum(fg) < 380 else (34, 34, 40)
	half = (cells + 1) // 2
	bits = int.from_bytes(h[3:11], "big")
	grid = [[False] * cells for _ in range(cells)]
	for y in range(cells):
		for x in range(half):
			on = bool(bits & 1)
			bits >>= 1
			grid[y][x] = grid[y][cells - 1 - x] = on
	cell = size // cells
	rows = []
	for py in range(cell * cells):
		row = bytearray(b"\x00")
		for px in range(cell * cells):
			row += bytes(fg if grid[py // cell][px // cell] else bg)
		rows.append(bytes(row))
	w = hgt = cell * cells
	return _png_bytes(w, hgt, b"".join(rows))


def _png_bytes(w, h, raw):
	def chunk(t, c):
		return struct.pack(">I", len(c)) + t + c + struct.pack(">I", zlib.crc32(t + c) & 0xffffffff)
	return (b"\x89PNG\r\n\x1a\n" + chunk(b"IHDR", struct.pack(">IIBBBBB", w, h, 8, 2, 0, 0, 0))
			+ chunk(b"IDAT", zlib.compress(raw, 9)) + chunk(b"IEND", b""))


def wav(seed, seconds=1.0, rate=8000):
	"""A mono 8-bit tone whose pitch comes from the seed."""
	h = hashlib.sha256(str(seed).encode()).digest()
	freq = 220 + h[0] * 2
	n = int(seconds * rate)
	samples = bytes(int(128 + 90 * math.sin(2 * math.pi * freq * i / rate)) for i in range(n))
	header = b"RIFF" + struct.pack("<I", 36 + n) + b"WAVEfmt " + struct.pack("<IHHIIHH", 16, 1, 1, rate, rate, 1, 8) \
		+ b"data" + struct.pack("<I", n)
	return header + samples


def file(name):
	with open(os.path.join(HERE, "media", name), "rb") as f:
		return f.read()


def upload(kind, seed):
	"""(filename, bytes, content type) for an upload of kind image, audio or video."""
	if kind == "image":
		return (f"town-{seed}.png", png(seed), "image/png")
	if kind == "audio":
		return (f"town-{seed}.ogg", file("tiny.ogg"), "audio/ogg")
	if kind == "video":
		return (f"town-{seed}.mp4", file("tiny.mp4"), "video/mp4")
	raise ValueError(kind)