#!/usr/bin/env python3
"""Reproducible graph identity and modulo-8 example; no website write.

Place beside the unchanged omega_joint_witness_v2.py; requires SymPy.
This exports a test fixture, not a complete network record protocol.
"""
import contextlib
import hashlib
import io
import json
from pathlib import Path
import omega_joint_witness_v2 as core


def main():
    trace = io.StringIO()
    with contextlib.redirect_stdout(trace):
        vertices, neighbors = core.build_graph()
        inverse, denominator = core.inverse_certificate(neighbors)
    graph = {
        'schema': 'OMEGA_600CELL_GRAPH_FIXTURE/1',
        'coordinate_rule': 'vertex coordinate is (a+b*phi)/2 for pair [a,b]',
        'vertex_order': 'Python lexicographic order of tuples of four integer pairs',
        'vertices': vertices,
        'neighbors': neighbors,
    }
    graph_bytes = (json.dumps(graph, ensure_ascii=True, sort_keys=True,
                             separators=(',', ':'))+'\n').encode('ascii')
    graph_digest = hashlib.sha256(graph_bytes).hexdigest()
    predecessor = tuple(range(120))
    output, remainder = core.full_step(predecessor, neighbors)
    wire = core.encode_joint_bytes(predecessor)
    stats = {}
    recovered = core.joint_decode(output, tuple(a % 8 for a in predecessor),
                                 neighbors, inverse, denominator,
                                 nonnegative=True, stats=stats,
                                 use_proposal=False, try_nearest=False)
    if recovered != predecessor or len(wire) != 45:
        raise RuntimeError('exact-only fixture recovery failed')
    if int.from_bytes(wire, 'little') != sum((a % 8) << (3*i)
                                            for i, a in enumerate(predecessor)):
        raise RuntimeError('wire convention failed')
    if any(core.Q*z != core.D*y+r for z, y, r in
           zip(core.m_apply(predecessor, neighbors), output, remainder)):
        raise RuntimeError('full remainder identity failed')
    bad_payloads = [b'', bytes(44), bytes(46)]
    for payload in bad_payloads:
        try:
            core.decode_joint_bytes(output, payload, neighbors, inverse, denominator)
        except ValueError:
            pass
        else:
            raise RuntimeError('wrong witness length accepted')
    fixture = {
        'schema': 'OMEGA_600CELL_MOD8_TEST_VECTOR/1',
        'graph_sha256': graph_digest,
        'core_source_sha256': hashlib.sha256(Path(core.__file__).read_bytes()).hexdigest(),
        'Q': str(core.Q), 'S': str(core.S), 'D': str(core.D),
        'state_domain': 'nonnegative integer vector of length 120',
        'predecessor': [str(a) for a in predecessor],
        'output': [str(a) for a in output],
        'residues_mod8': [a % 8 for a in predecessor],
        'witness_hex': wire.hex(),
        'witness_bytes': len(wire),
        'witness_endianness': 'little',
        'decoder_path': 'exact propagation/search; nearest and MILP disabled',
        'exact_search_statistics': stats,
        'malformed_length_cases_rejected': len(bad_payloads),
        'status': 'PASS',
    }
    Path('graph-fixture.json').write_bytes(graph_bytes)
    Path('joint-witness-test-vector.json').write_text(
        json.dumps(fixture, indent=2)+'\n', encoding='utf-8')
    print(json.dumps({'status': 'PASS', 'graph_sha256': graph_digest,
                      'witness_hex': wire.hex(), 'exact_search': stats,
                      'invalid_lengths_rejected': len(bad_payloads)}, indent=2))


if __name__ == '__main__':
    main()