#!/usr/bin/env python3
"""wai.pack.scenecut/1, differentially: wai-pack's streaming segmenter against
pack_verify.py's on-demand form.

Seeded random clips (flat and noisy shots, cuts, flashes, small perturbations, empty and
one-frame clips) under random parameters; every piece (start, length, flags and the
statistics classification reads) and every score from `wai-pack segment-json`, pushed
a frame at a time or in a batch, must equal pack_verify.py's, and every piece but the
last must lie between `min` and `max` frames (the last at most `max`).

    python3 segment_diff.py <wai-pack binary> [seed] [count]

Exit status 0 only if every clip agrees.
"""
import json
import os
import random
import subprocess
import sys

HERE = os.path.dirname(os.path.abspath(__file__))
sys.path.insert(0, HERE)
import pack_verify as PV  # noqa: E402


def clip(rng):
    w, h = rng.randint(1, 5), rng.randint(1, 4)
    scenes = []
    for _ in range(rng.randint(1, 5)):
        if rng.random() < 0.5:
            scenes.append([rng.randrange(256)] * (w * h * 3))
        else:
            scenes.append([rng.randrange(256) for _ in range(w * h * 3)])
    n = rng.randint(0, 40) if rng.random() < 0.9 else rng.randint(0, 3)
    frames, cur = [], 0
    for _ in range(n):
        if rng.random() < 0.15:
            cur = rng.randrange(len(scenes))
        f = scenes[cur]
        if rng.random() < 0.1:
            f = scenes[rng.randrange(len(scenes))]
        if rng.random() < 0.2:
            f = [min(255, max(0, x + rng.randint(-6, 6))) for x in f]
        frames.append(list(f))
    mn = rng.randint(1, 6)
    tg = mn + rng.randint(0, 6)
    mx = tg + rng.randint(0, 8)
    p = {"min": mn, "target": tg, "max": mx, "cut_abs": rng.choice([1, 50, 100, 300, 500, 1000]),
         "cut_rel": rng.choice([0, 1000, 3000, 1000000]), "window": rng.randint(1, 8), "lookahead": rng.randint(0, 7)}
    return {"w": w, "h": h, "p": p, "frames": frames, "stream": rng.random() < 0.5}


def main(argv):
    if len(argv) < 2:
        print(__doc__)
        return 2
    binary = argv[1]
    seed = int(argv[2]) if len(argv) > 2 else 1
    count = int(argv[3]) if len(argv) > 3 else 2000
    rng = random.Random(seed)
    cases = [clip(rng) for _ in range(count)]
    r = subprocess.run([binary, "segment-json"], input=("\n".join(json.dumps(c) for c in cases) + "\n").encode(),
                       capture_output=True)
    outs = r.stdout.decode().splitlines()
    if r.returncode != 0 or len(outs) != count:
        print(r.stderr.decode(errors="replace")[-2000:])
        return 1
    bad = 0
    for c, o in zip(cases, outs):
        ro = json.loads(o)
        if not c["frames"]:
            ok = ro["pieces"] == []
        else:
            pp, ps = PV.segment(c["frames"], c["w"], c["h"], c["p"])
            py = [[x["start"], x["len"], x["flags"], x["abs_diff"], x["changed"], x["compared"], x["occupancy"]] for x in pp]
            ok = py == ro["pieces"] and ps == ro["scores"]
        pcs = ro["pieces"]
        for i, x in enumerate(pcs):
            if x[1] > c["p"]["max"] or (i + 1 < len(pcs) and x[1] < c["p"]["min"]):
                ok = False
        if not ok:
            bad += 1
            if bad <= 5:
                print("DIFF", json.dumps(c["p"]), "frames", len(c["frames"]), "stream", c["stream"])
    print(f"segment_diff: seed {seed}, {count} clips, {bad} differences")
    return 0 if bad == 0 else 1


if __name__ == "__main__":
    sys.exit(main(sys.argv))