#!/usr/bin/env python3
"""Python environment health check for the spark lane.

The dependency list is the lane's own third-party imports, measured from
`wizard-work/spark/*.py` (`grep -rhoE '^(import|from) +[A-Za-z0-9_.]+'`):

    PyYAML      -> yaml        debug_yaml.py:2
    numpy       -> numpy       qc_analyze.py:7
    Pillow      -> PIL         ascii_tool.py:12, qc_analyze.py:6
    jsonschema  -> jsonschema  validate_json_schema.py:14

`email_validator` is deliberately NOT declared: the lane's
`wizard-work/spark/email_validator.py` is a local, stdlib-only module, so
declaring the PyPI distribution would test a package the lane never uses.

The check can fail. A dependency that will not import is reported as
`"status": "missing"` and the process exits 1; a package that imports but
raises something other than ImportError is reported as `"status": "broken"`.
`--require` appends a dependency for one run, which is how the committed
cell in `test_python_env_check.py` proves the red path with a package that
is genuinely absent on the host.

Exit codes (tools/ contract):
    0  every declared dependency imports and reports
    1  at least one declared or --require'd dependency is missing/broken
    2  usage error (argparse)
"""

import argparse
import importlib
import importlib.metadata
import json
import sys
from datetime import datetime, timezone

# (distribution name, import name) for the lane's own third-party imports
DEPENDENCIES = (
    ("PyYAML", "yaml"),
    ("numpy", "numpy"),
    ("Pillow", "PIL"),
    ("jsonschema", "jsonschema"),
)


def check_package(distribution, import_name=None):
    """Import one dependency by name and report its version.

    The version is read from the distribution metadata first; `__version__`
    is the fallback for packages that ship no metadata record.
    """
    import_name = import_name or distribution
    try:
        mod = importlib.import_module(import_name)
    except ImportError as exc:
        return {
            "status": "missing",
            "available": False,
            "import_name": import_name,
            "error": "%s: %s" % (type(exc).__name__, exc),
        }
    except Exception as exc:  # a package that raises on import is not healthy
        return {
            "status": "broken",
            "available": False,
            "import_name": import_name,
            "error": "%s: %s" % (type(exc).__name__, exc),
        }
    try:
        version = importlib.metadata.version(distribution)
    except importlib.metadata.PackageNotFoundError:
        version = getattr(mod, "__version__", "unknown")
    return {
        "status": "ok",
        "available": True,
        "import_name": import_name,
        "version": version,
    }


def parse_requirement(text):
    """`NAME` or `DISTRIBUTION:IMPORT` -> (distribution, import name)."""
    if ":" in text:
        distribution, import_name = text.split(":", 1)
        if not distribution or not import_name:
            raise argparse.ArgumentTypeError(
                "--require needs NAME or DISTRIBUTION:IMPORT, got %r" % text
            )
        return distribution, import_name
    return text, text


def build_parser():
    parser = argparse.ArgumentParser(
        prog="python-env-check.py",
        description="Verify the spark lane's third-party dependencies import, "
        "and report their versions.",
    )
    parser.add_argument(
        "--require",
        metavar="NAME[:IMPORT]",
        action="append",
        default=[],
        type=parse_requirement,
        help="also require this package for this run (repeatable); "
        "useful for proving the red path",
    )
    return parser


def main(argv=None):
    args = build_parser().parse_args(argv)
    declared = list(DEPENDENCIES) + list(args.require)
    packages = {}
    for distribution, import_name in declared:
        result = check_package(distribution, import_name)
        result["distribution"] = distribution
        packages[import_name] = result
    missing = sorted(
        name for name, result in packages.items() if result["status"] != "ok"
    )
    output = {
        "all_ok": not missing,
        "timestamp": datetime.now(timezone.utc).isoformat(),
        "dependencies_declared": len(declared),
        "missing": missing,
        "components": {
            "python": {
                "status": "ok",
                "version": sys.version,
                "executable": sys.executable,
            },
            "packages": packages,
        },
    }
    print(json.dumps(output, indent=2, sort_keys=True))
    return 0 if not missing else 1


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