#!/usr/bin/env python3
"""When does the mission script become resident in guest memory?

One run reached `IN FLIGHT` with the `.ssb` header ABSENT from guest memory and
`find_mission` returning NOTFOUND, while the manifest string `Stage02.ssb` was
present (script-runtime-probe.md). Three explanations were possible: the script
loads later than assumed, the probe raced a load, or that run never really
entered the mission.

Sampling once cannot separate them. This polls from the moment flight is
detected and records WHEN each marker appears:

    header    the .ssb's 20-byte header  -> the script image itself
    ADN110    a symbol-table string      -> its symbol table
    mission   find_mission() succeeding  -> the live ScriptMission

Usage: ssb_watch.py [secs] [every_s]
"""
import os
import sys
import time

sys.path.insert(0, __file__.rsplit('/', 1)[0])
import gmem
import isl
import squadron_state as S

def main():
    ssb = isl.load('/tmp/Stage02.ssb')
    hdr = ssb[:20]
    secs = float(sys.argv[1]) if len(sys.argv) > 1 else 300
    every = float(sys.argv[2]) if len(sys.argv) > 2 else 10
    path = gmem.mem_path()
    size = os.path.getsize(path)
    t0 = time.time()
    seen = {}
    with open(path, 'rb', buffering=0) as f:
        while time.time() - t0 < secs:
            t = time.time() - t0
            marks = {}
            marks['header'] = len(S._find(f, size, hdr))
            marks['ADN110'] = len(S._find(f, size, b'ADN110'))
            m, _fb = (None, None)
            if marks['header']:
                m, _fb = S.find_mission(f, size, ssb)
            marks['mission'] = 1 if m else 0
            for k, v in marks.items():
                if v and k not in seen:
                    seen[k] = t
                    print('  [%6.1fs] %-8s FIRST SEEN (%s)' % (t, k, v), flush=True)
            print('  [%6.1fs] header=%d ADN110=%d mission=%s' % (
                t, marks['header'], marks['ADN110'],
                ('0x%08X' % m) if m else 'no'), flush=True)
            if len(seen) == 3:
                print('all three resident at %.1fs' % t, flush=True)
                return 0
            time.sleep(every)
    print('timed out; seen=%s' % seen, flush=True)
    return 1


if __name__ == '__main__':
    sys.exit(main())