#!/usr/bin/env python3
"""Evaluate technical conformance separately from one named target consumer."""

from __future__ import annotations

import argparse
import json
import subprocess
import sys
import tempfile
from pathlib import Path
from typing import Any

VERDICTS = {"PASS", "FAIL", "BLOCKED", "UNVERIFIED"}


class ContractError(Exception):
    pass


def load(path: str, label: str) -> dict[str, Any]:
    try:
        value = json.loads(Path(path).read_text())
    except (OSError, json.JSONDecodeError) as exc:
        raise ContractError(f"could not load {label}: {exc}") from exc
    if not isinstance(value, dict):
        raise ContractError(f"{label} root must be an object")
    return value


def target_sources(target: dict[str, Any]) -> None:
    basis = target.get("requirement_basis")
    if basis not in {"official_documentation", "observed_behavior", "mixed"}:
        raise ContractError(
            "target requirement_basis must be official_documentation, observed_behavior, or mixed"
        )
    sources = target.get("sources")
    if not isinstance(sources, list) or not sources:
        raise ContractError("target requirements need at least one source record")
    for source in sources:
        if (
            not isinstance(source, dict)
            or not source.get("locator")
            or not source.get("accessed_at")
            or not source.get("claim")
        ):
            raise ContractError("each target source needs locator, accessed_at, and claim")
        if source.get("basis") not in {"official_documentation", "observed_behavior"}:
            raise ContractError("each target source needs an explicit evidence basis")


def overall(*verdicts: str) -> str:
    for verdict in ("FAIL", "BLOCKED", "UNVERIFIED"):
        if verdict in verdicts:
            return verdict
    return "PASS"


def run_technical(contract: dict[str, Any], probe_path: str) -> dict[str, Any]:
    isolated = dict(contract)
    isolated["downstream"] = {}
    with tempfile.NamedTemporaryFile(mode="w", suffix=".json") as temporary:
        json.dump(isolated, temporary)
        temporary.flush()
        command = [
            sys.executable,
            str(Path(__file__).with_name("media-verify")),
            temporary.name,
            probe_path,
            "--json",
        ]
        result = subprocess.run(command, capture_output=True, text=True, check=False)
    try:
        report = json.loads(result.stdout)
    except json.JSONDecodeError as exc:
        raise ContractError("technical verifier did not return JSON") from exc
    if result.returncode == 2:
        raise ContractError(str(report.get("error", "invalid technical contract")))
    report["boundary"] = "local_ffprobe_and_declared_technical_requirements"
    return report


def add_maximum(criteria: list[dict[str, Any]], name: str, observed: Any, maximum: Any) -> str:
    try:
        actual = float(observed)
        limit = float(maximum)
    except (TypeError, ValueError):
        verdict = "UNVERIFIED"
        reason = "probe value or maximum is absent or nonnumeric"
    else:
        verdict = "PASS" if actual <= limit else "FAIL"
        reason = None if verdict == "PASS" else "observed value exceeds target maximum"
    criteria.append(
        {
            "criterion": name,
            "boundary": "target_technical_policy",
            "verdict": verdict,
            "expected": {"maximum": maximum},
            "observed": observed,
            "evidence": "output probe",
            "reason": reason,
        }
    )
    return verdict


def downstream_result(
    target: dict[str, Any], lane: dict[str, Any], evidence: dict[str, Any]
) -> dict[str, Any]:
    target_id = target["id"]
    result = evidence.get("target_consumer")
    if isinstance(result, dict):
        verdict = result.get("status")
        if verdict not in VERDICTS:
            verdict = "UNVERIFIED"
            reason = "target-consumer status is missing or invalid"
        elif result.get("target_id") != target_id:
            verdict = "FAIL"
            reason = "target-consumer evidence names a different target"
        elif not result.get("artifact") or not result.get("method"):
            verdict = "UNVERIFIED"
            reason = "target-consumer evidence needs artifact identity and method"
        else:
            reason = result.get("reason")
        return {
            "target_id": target_id,
            "target_version": result.get("target_version"),
            "verdict": verdict,
            "method": result.get("method"),
            "artifact": result.get("artifact"),
            "warnings": result.get("warnings", []),
            "reason": reason,
            "boundary": "named_target_consumer",
        }
    unavailable = lane.get("unavailable_reason")
    return {
        "target_id": target_id,
        "target_version": None,
        "verdict": "BLOCKED" if unavailable else "UNVERIFIED",
        "method": lane.get("method"),
        "artifact": None,
        "warnings": [],
        "reason": unavailable or "no evidence from the named target consumer was supplied",
        "boundary": "named_target_consumer",
    }


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("manifest")
    parser.add_argument("output_probe")
    parser.add_argument("--target-evidence")
    parser.add_argument("--json", action="store_true")
    args = parser.parse_args()
    try:
        manifest = load(args.manifest, "compatibility manifest")
        probe = load(args.output_probe, "output probe")
        evidence = load(args.target_evidence, "target evidence") if args.target_evidence else {}
        if manifest.get("schema_version") != 1:
            raise ContractError("compatibility manifest schema_version must be 1")
        target = manifest.get("target")
        contract = manifest.get("technical_requirements")
        lane = manifest.get("target_lane")
        if not isinstance(target, dict) or not target.get("id") or not target.get("name"):
            raise ContractError("target needs id and name")
        if not isinstance(contract, dict) or not isinstance(lane, dict):
            raise ContractError("technical_requirements and target_lane must be objects")
        target_sources(target)
        technical = run_technical(contract, args.output_probe)
        limits = manifest.get("target_limits", {})
        if not isinstance(limits, dict):
            raise ContractError("target_limits must be an object")
        limit_verdicts: list[str] = []
        if "maximum_duration_seconds" in limits:
            limit_verdicts.append(
                add_maximum(
                    technical["criteria"],
                    "target_maximum_duration",
                    probe.get("format", {}).get("duration"),
                    limits["maximum_duration_seconds"],
                )
            )
        if "maximum_file_size_bytes" in limits:
            limit_verdicts.append(
                add_maximum(
                    technical["criteria"],
                    "target_maximum_file_size",
                    probe.get("format", {}).get("size"),
                    limits["maximum_file_size_bytes"],
                )
            )
        technical["overall_verdict"] = overall(technical["overall_verdict"], *limit_verdicts)
        target_result = downstream_result(target, lane, evidence)
        verdict = overall(technical["overall_verdict"], target_result["verdict"])
        payload = {
            "ok": verdict == "PASS",
            "schema_version": 1,
            "target": target,
            "requirements_provenance": target["sources"],
            "technical_probe_result": technical,
            "target_consumer_result": target_result,
            "overall_verdict": verdict,
            "boundary_statement": f"This result applies only to target {target['id']}; local FFprobe/FFmpeg success and this target result do not establish compatibility with any other player, editor, host, archive, or service.",
            "platform_operation": "not_performed",
        }
        print(
            json.dumps(payload, sort_keys=True, separators=(",", ":"))
            if args.json
            else json.dumps(payload, indent=2, sort_keys=True)
        )
        return 0 if verdict == "PASS" else 1
    except ContractError as exc:
        print(
            json.dumps({"ok": False, "status": "INVALID_INPUT", "error": str(exc)}, sort_keys=True)
        )
        return 2


if __name__ == "__main__":
    raise SystemExit(main())