#!/usr/bin/env python3
"""Validate the schema fixtures against the FLUID wire-contract schemas.

Every fixture is transcribed from a worked example in spec/. If the
specification moves and the schemas do not, this fails the build.
"""
import json
import pathlib
import sys

import yaml
from jsonschema import Draft202012Validator, RefResolver

ROOT = pathlib.Path(__file__).resolve().parent.parent
SCHEMAS = ROOT / "schemas"
FIXTURES = ROOT / "conformance" / "fixtures"

# fixture stem -> schema stem
PAIRS = {
    "pressure": "pressure",
    "hypothesis": "hypothesis",
    "revision": "revision",
    "experiment": "experiment",
    "event": "event",
    "feedback": "feedback",
    "backend-requirement": "backend-requirement",
    "revision-descriptor": "revision-descriptor",
    "routing-policy": "routing-policy",
    "telemetry-envelope": "telemetry-envelope",
}


def load_store():
    """Map every schema by both its $id and its bare filename.

    Schemas cross-reference each other as "common.schema.json#/$defs/...",
    a relative reference, so the bare filename has to resolve too.
    """
    store = {}
    for path in SCHEMAS.glob("*.schema.json"):
        schema = json.loads(path.read_text())
        store[path.name] = schema
        if "$id" in schema:
            store[schema["$id"]] = schema
    return store


# Instances that MUST be rejected. Without these the suite could pass
# vacuously if reference resolution silently degraded to "accept anything".
NEGATIVE = [
    (
        "pressure",
        "pressure without evidence references is not auditable",
        {"fluid_pressure": {
            "schema_version": "0.1", "id": "P-1", "interface_id": "x",
            "class": "natural_usage", "first_seen": "2026-01-01T00:00:00Z",
            "last_seen": "2026-01-01T00:00:00Z", "summary": "s",
            "evidence_refs": [], "status": "OPEN"}},
    ),
    (
        "pressure",
        "pressure class outside the standard taxonomy",
        {"fluid_pressure": {
            "schema_version": "0.1", "id": "P-1", "interface_id": "x",
            "class": "vibes", "first_seen": "2026-01-01T00:00:00Z",
            "last_seen": "2026-01-01T00:00:00Z", "summary": "s",
            "evidence_refs": ["telemetry:1"], "status": "OPEN"}},
    ),
    (
        "hypothesis",
        "hypothesis with no falsifiable expected outcome",
        {"fluid_hypothesis": {
            "schema_version": "0.1", "id": "H-1", "interface_id": "x",
            "state": "DRAFT", "title": "t",
            "observation": {"summary": "s", "evidence_refs": ["telemetry:1"]},
            "pressure": {"classes": ["natural_usage"]},
            "explanation": {"claim": "c"},
            "proposed_adaptation": {"class": "contract", "summary": "s"},
            "expected_outcomes": [],
            "guardrails": [],
            "complexity": {"expected_delta": {}},
            "risk": {"level": "LOW"},
            "success_criteria": {"expression": "e"}}},
    ),
    (
        "experiment",
        "experiment with no stop condition is not interruptible by policy",
        {"fluid_experiment": {
            "schema_version": "0.1", "id": "E-1", "interface_id": "x",
            "hypothesis_refs": ["H-1"], "control_revision": "R-1",
            "candidate_revisions": ["R-2"],
            "allocation": {"control": 0.9, "candidate": 0.1},
            "metrics": {"primary": ["m"]},
            "stop_conditions": [],
            "result": {"state": "PLANNED"}}},
    ),
    (
        "revision-descriptor",
        "descriptor with no governing intent cannot be audited",
        {"revision": {
            "schema_version": "0.1", "id": "R-1", "interface": "x",
            "state": "stable",
            "contract": {"type": "openapi", "digest": "sha256:" + "0" * 64},
            "runtime": {"upstream": "http://a:8080"},
            "policy": {"compatibility": "additive", "security_check": "passed"}}},
    ),
    (
        "revision-descriptor",
        "unknown revision state",
        {"revision": {
            "schema_version": "0.1", "id": "R-1", "interface": "x",
            "state": "probably-fine",
            "contract": {"type": "openapi", "digest": "sha256:" + "0" * 64},
            "runtime": {"upstream": "http://a:8080"},
            "intent": {"version": "IEI-1"},
            "policy": {"compatibility": "additive", "security_check": "passed"}}},
    ),
]


def run_negative(store):
    failures = 0
    for schema_stem, why, instance in NEGATIVE:
        schema = json.loads((SCHEMAS / f"{schema_stem}.schema.json").read_text())
        resolver = RefResolver(base_uri="", referrer=schema, store=store)
        validator = Draft202012Validator(schema, resolver=resolver)
        if validator.is_valid(instance):
            print(f"FAIL     rejected-case accepted: {why}")
            failures += 1
        else:
            print(f"ok       rejects: {why}")
    return failures


def main() -> int:
    store = load_store()
    failures = 0

    for fixture_stem, schema_stem in sorted(PAIRS.items()):
        fixture_path = FIXTURES / f"{fixture_stem}.yaml"
        schema_path = SCHEMAS / f"{schema_stem}.schema.json"

        if not fixture_path.exists():
            print(f"MISSING  {fixture_path.relative_to(ROOT)}")
            failures += 1
            continue

        schema = json.loads(schema_path.read_text())
        instance = yaml.safe_load(fixture_path.read_text())

        resolver = RefResolver(base_uri="", referrer=schema, store=store)
        validator = Draft202012Validator(schema, resolver=resolver)

        errors = sorted(validator.iter_errors(instance), key=lambda e: list(e.path))
        if errors:
            failures += 1
            print(f"FAIL     {fixture_stem}")
            for err in errors:
                where = "/".join(str(p) for p in err.absolute_path) or "<root>"
                print(f"           {where}: {err.message}")
        else:
            print(f"ok       {fixture_stem}")

    # A schema that no fixture exercises is a schema nothing protects.
    unexercised = {
        p.stem.removesuffix(".schema")
        for p in SCHEMAS.glob("*.schema.json")
    } - set(PAIRS.values()) - {"common"}
    for stem in sorted(unexercised):
        print(f"WARN     {stem}.schema.json has no fixture")

    # Emit JSON copies so the Go round-trip test can read fixtures without a
    # YAML dependency (the build stays free of third-party Go modules).
    json_dir = FIXTURES / "json"
    json_dir.mkdir(exist_ok=True)
    for fixture_stem in PAIRS:
        instance = yaml.safe_load((FIXTURES / f"{fixture_stem}.yaml").read_text())
        (json_dir / f"{fixture_stem}.json").write_text(
            json.dumps(instance, indent=2, sort_keys=True) + "\n"
        )

    print()
    failures += run_negative(store)

    if failures:
        print(f"\n{failures} check(s) failed")
        return 1
    print(f"\nAll {len(PAIRS)} fixtures validate; all {len(NEGATIVE)} rejected cases refused")
    return 0


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