src/flc_core.py

import os, struct, math
import numpy as np
from PIL import Image, ImageDraw

PHI = (1.0 + 5.0**0.5) / 2.0
MAGIC = b"FLC1\x00\x00\x00\x00"
VER_V2 = 2

# --- Fibonacci & Frequency Logic ---
def fibonacci_sequence(n):
    fibs = [1, 2]
    while len(fibs) < n:
        fibs.append(fibs[-1] + fibs[-2])
    return np.array(fibs[:n], dtype=np.int64)

def fibonacci_sequence_std(n):
    fibs = [1, 1]
    while len(fibs) < n:
        fibs.append(fibs[-1] + fibs[-2])
    return np.array(fibs[:n], dtype=np.int64)

def fibonacci_frequency_boundaries(n_coeffs: int, n_bands: int):
    if n_bands < 2: return [0, n_coeffs]
    fibs = fibonacci_sequence(n_bands).astype(np.float64)
    w = fibs / (fibs.sum() + 1e-12)
    cum = np.cumsum(w)
    b = [0]
    for i in range(n_bands - 1):
        b.append(int(round(n_coeffs * cum[i])))
    b.append(n_coeffs)
    # Ensure strict monotonicity
    for i in range(1, len(b)):
        if b[i] <= b[i-1]: b[i] = b[i-1] + 1
    return b

# --- Orthonormal DCT Engine ---
def dct_ortho_1d(x: np.ndarray) -> np.ndarray:
    N = x.shape[0]
    v = np.concatenate([x, x[::-1]])
    V = np.fft.fft(v)
    k = np.arange(N)
    X = np.real(V[:N] * np.exp(-1j * np.pi * k / (2 * N)))
    X *= 2.0
    X[0] *= (1.0 / math.sqrt(4 * N))
    X[1:] *= (1.0 / math.sqrt(2 * N))
    return X

def idct_ortho_1d(X: np.ndarray) -> np.ndarray:
    N = X.shape[0]
    x0, xr = X[0] * math.sqrt(4 * N), X[1:] * math.sqrt(2 * N)
    c = np.empty(N, dtype=np.complex128)
    c[0], c[1:] = x0 / 2.0, xr / 2.0
    k = np.arange(N)
    c = c * np.exp(1j * np.pi * k / (2 * N))
    V = np.zeros(2 * N, dtype=np.complex128)
    V[:N] = c
    V[N+1:] = np.conj(c[1:][::-1])
    return np.fft.ifft(V).real[:N]

def dct_blocks_ortho(x_blocks: np.ndarray) -> np.ndarray:
    return np.array([dct_ortho_1d(b) for b in x_blocks])

def idct_blocks_ortho(X_blocks: np.ndarray) -> np.ndarray:
    return np.array([idct_ortho_1d(B) for B in X_blocks])

# --- Fibonacci Coding (Bit IO) ---
class BitWriter:
    def __init__(self):
        self.buf, self.acc, self.nbits = bytearray(), 0, 0
    def write_bit(self, b: int):
        self.acc = (self.acc << 1) | (b & 1)
        self.nbits += 1
        if self.nbits == 8:
            self.buf.append(self.acc); self.acc = 0; self.nbits = 0
    def finish(self):
        if self.nbits: self.buf.append(self.acc << (8 - self.nbits))
        return bytes(self.buf)

class BitReader:
    def __init__(self, data: bytes):
        self.data, self.i, self.acc, self.nbits = data, 0, 0, 0
    def read_bit(self):
        if self.nbits == 0:
            self.acc = self.data[self.i]; self.i += 1; self.nbits = 8
        b = (self.acc >> (self.nbits - 1)) & 1
        self.nbits -= 1
        return b

def fib_encode_nonneg(bw, n):
    m = int(n) + 1
    fibs = [1, 2]
    while fibs[-1] <= m: fibs.append(fibs[-1] + fibs[-2])
    bits = [0] * (len(fibs) - 1)
    for i in reversed(range(len(bits))):
        if fibs[i] <= m: bits[i] = 1; m -= fibs[i]
    for i in range(max((i for i, b in enumerate(bits) if b), default=0) + 1):
        bw.write_bit(bits[i])
    bw.write_bit(1)

def fib_decode_nonneg(br):
    fibs, bits, prev = [1, 2], [], 0
    while True:
        b = br.read_bit(); bits.append(b)
        if prev == 1 and b == 1: break
        prev = b
        if len(bits) > len(fibs): fibs.append(fibs[-1] + fibs[-2])
    m = sum(fibs[i] for i, bi in enumerate(bits[:-1]) if bi)
    return m - 1

def rle_fib_encode_ints(ints):
    bw = BitWriter()
    zrun = 0
    for v in ints:
        if v == 0: zrun += 1; continue
        if zrun: bw.write_bit(0); fib_encode_nonneg(bw, zrun); zrun = 0
        bw.write_bit(1); fib_encode_nonneg(bw, (v << 1) ^ (v >> 63))
    if zrun: bw.write_bit(0); fib_encode_nonneg(bw, zrun)
    return bw.finish()

def rle_fib_decode_ints(payload, n_out):
    br, out, i = BitReader(payload), np.zeros(n_out, dtype=np.int64), 0
    while i < n_out:
        if br.read_bit() == 0: i = min(n_out, i + fib_decode_nonneg(br))
        else:
            u = fib_decode_nonneg(br)
            out[i] = (u >> 1) ^ (-(u & 1)); i += 1
    return out

# --- Quantization & Spiral Visuals ---
def band_quantize_dct(coeffs, boundaries, base_step):
    q = np.zeros_like(coeffs, dtype=np.int32)
    for bi in range(len(boundaries) - 1):
        a, b = boundaries[bi], boundaries[bi + 1]
        step = base_step * (PHI ** bi)
        q[:, a:b] = np.round(coeffs[:, a:b] / step)
    return q

def band_dequantize_dct(q, boundaries, base_step):
    coeffs = np.zeros_like(q, dtype=np.float64)
    for bi in range(len(boundaries) - 1):
        a, b = boundaries[bi], boundaries[bi + 1]
        step = base_step * (PHI ** bi)
        coeffs[:, a:b] = q[:, a:b] * step
    return coeffs

def hologram_spectrum_image(zints, max_symbols=262144):
    z = zints[:max_symbols]; v = np.tanh(z / 32.0)
    theta = (2 * math.pi / (PHI**2)) * np.arange(v.size) + 2.0 * math.pi * (v * 0.25)
    r = 1.0 + 0.35 * np.abs(v)
    syms = r * np.cos(theta) + 1j * r * np.sin(theta)
    N = int(2**math.ceil(math.log2(math.sqrt(syms.size or 1))))
    U = np.pad(syms, (0, N*N - syms.size)).reshape(N, N)
    mag = np.log1p(np.abs(np.fft.fftshift(np.fft.fft2(U))))
    mag = (mag - mag.min()) / (mag.max() - mag.min() + 1e-12)
    return (mag * 255).astype(np.uint8)

def bytes_to_fib_spiral_image(data, max_pixels=262144):
    arr = np.frombuffer(data, dtype=np.uint8)[:max_pixels]
    fibs = fibonacci_sequence_std(32)
    sizes, area = [], 0
    for s in fibs:
        sizes.append(int(s)); area += s*s
        if area >= arr.size: break
    # Simple tile placement logic for demo
    tiles, minx, miny, maxx, maxy = [], 0, 0, 0, 0
    curr_x, curr_y = 0, 0
    for i, s in enumerate(sizes):
        d = (i-1)%4
        if i>0:
            if d==0: curr_x = maxx; curr_y = miny
            elif d==1: curr_x = maxx-s; curr_y = maxy
            elif d==2: curr_x = minx-s; curr_y = maxy-s
            else: curr_x = minx; curr_y = miny-s
        tiles.append((curr_x, curr_y, s))
        minx, miny = min(minx, curr_x), min(miny, curr_y)
        maxx, maxy = max(maxx, curr_x+s), max(maxy, curr_y+s)
    
    W, H = maxx-minx, maxy-miny
    img = np.zeros((H, W), dtype=np.uint8)
    idx = 0
    for x, y, s in tiles:
        take = min(s*s, arr.size - idx)
        if take <= 0: break
        block = np.pad(arr[idx:idx+take], (0, s*s-take)).reshape(s, s)
        img[H-(y-miny+s):H-(y-miny), x-minx:x-minx+s] = block
        idx += take
    return img, tiles, (minx, miny, maxx, maxy)

# --- High Level API ---
def flc_encode_file(in_path, out_flc, preview_png=None, unzip_gif=None, block_len=1024, n_bands=10, base_step=0.004, **kwargs):
    raw = open(in_path, "rb").read()
    x = (np.frombuffer(raw, dtype=np.uint8).astype(np.float64) - 127.5) / 127.5
    pad = (-x.size) % block_len
    X = np.pad(x, (0, pad)).reshape(-1, block_len)
    C = dct_blocks_ortho(X)
    bnds = fibonacci_frequency_boundaries(block_len, n_bands)
    Q = band_quantize_dct(C, bnds, base_step)
    payload = rle_fib_encode_ints(np.diff(Q.flatten(), prepend=0))
    
    header = struct.pack("<8sH Q I I H d d H", MAGIC, VER_V2, len(raw), block_len, X.shape[0], n_bands, base_step, 127.5, len(bnds))
    with open(out_flc, "wb") as f:
        f.write(header); f.write(struct.pack("<"+ "I"*len(bnds), *bnds))
        f.write(struct.pack("<I", len(payload))); f.write(payload)

    if unzip_gif: # Generate the unzip frames
        frames = []
        for t in range(1, n_bands + 1):
            Q_p = np.zeros_like(Q)
            for bi in range(t): Q_p[:, bnds[bi]:bnds[bi+1]] = Q[:, bnds[bi]:bnds[bi+1]]
            X_p = idct_blocks_ortho(band_dequantize_dct(Q_p, bnds, base_step))
            recon = np.clip((X_p.flatten()[:len(raw)] * 127.5) + 127.5, 0, 255).astype(np.uint8)
            
            # Create Frame
            h_img = Image.fromarray(hologram_spectrum_image(Q_p.flatten())).resize((256, 256))
            s_img_arr, _, _ = bytes_to_fib_spiral_image(recon.tobytes())
            s_img = Image.fromarray(s_img_arr).resize((256, 256))
            
            frame = Image.new("RGB", (512, 280), (10, 10, 15))
            frame.paste(h_img, (0, 24)); frame.paste(s_img, (256, 24))
            frames.append(frame)
        frames[0].save(unzip_gif, save_all=True, append_images=frames[1:], duration=100, loop=0)

    return {"n_bytes": len(raw), "payload_len": len(payload), "ratio": len(payload)/len(raw)}

def flc_decode_file(in_flc, out_path):
    blob = open(in_flc, "rb").read()
    h_sz = struct.calcsize("<8sH Q I I H d d H")
    magic, ver, n_bytes, b_len, n_blks, n_bnds, step, mu, bnd_l = struct.unpack_from("<8sH Q I I H d d H", blob)
    off = h_sz
    bnds = struct.unpack_from("<" + "I"*bnd_l, blob, off); off += 4*bnd_l
    p_len = struct.unpack_from("<I", blob, off)[0]; off += 4
    d = rle_fib_decode_ints(blob[off:off+p_len], n_blks * b_len)
    Q = np.cumsum(d).reshape(n_blks, b_len)
    X = idct_blocks_ortho(band_dequantize_dct(Q, bnds, step))
    res = np.clip((X.flatten()[:n_bytes] * 127.5) + mu, 0, 255).astype(np.uint8)
    with open(out_path, "wb") as f: f.write(res.tobytes())
    return {"n_bytes": n_bytes}

def cosine_similarity_bytes(a, b):
    x = np.frombuffer(a, dtype=np.uint8).astype(float)
    y = np.frombuffer(b, dtype=np.uint8).astype(float)
    n = min(len(x), len(y))
    x, y = x[:n]-x[:n].mean(), y[:n]-y[:n].mean()
    return np.dot(x, y) / (np.linalg.norm(x) * np.linalg.norm(y) + 1e-12)