"""Check a run's selection inputs against the branch before anything deploys.

Usage:
  python -m cli.meta.ci.validate [--whitelist "..."] [--priority "..."]
      [--modes auto] [--tor auto] [--distros "..."] [--filesystem "..."]
      [--lifecycles "..."]

A selection token names a row that has to exist *on this branch*
(:mod:`utils.github.variant.selection`). Nothing else in the chain can tell
the operator that early: the matrix builder raises on the first bad token, one
per chunk job, so a stale list costs one full CI round per entry and reports
the second problem only after the first is fixed. Every problem is collected
here instead, and the exit code gates the run.

What makes a token bad, in the order this checks it:

* it does not parse, or names a mode or onion state that does not exist;
* it pins a variant the role does not declare (any more): the usual case is a
  list carried over from an older run whose variants have since been renumbered;
* it pins a mode the row cannot take, an onion state the row, the mode or the
  run's own tor axis rules out, or a distro or filesystem the run's own pool
  does not hold.

A token naming a role the discovery query does not return at all is reported
too, but as a warning, whether or not it pins axes: the diff-derived whitelist
legitimately names roles the envelope filters out, and it pins the variants a
change reaches. Role names themselves are checked against `roles/` before the
run starts (scripts/github/resolve/effective_whitelist.sh), so a typo is caught
there rather than swallowed here.
"""

from __future__ import annotations

import argparse
import sys

from cli.meta.ci import query
from utils.cache.applications import get_variants
from utils.github.variant import axes, pools, selection, tor
from utils.roles.display import display_names


def problems(
    tokens: str,
    *,
    modes: tuple[str, ...],
    tor_mode: str,
    distros: tuple[str, ...],
    filesystems: tuple[str, ...],
    lifecycles: str,
    label: str,
) -> tuple[list[str], list[str]]:
    """Every reason the tokens of one input cannot deploy on this branch.

    A token that narrows nothing beyond the role name is answered by existence:
    it asks for the role in whatever axes the rotation picks, so any discovered
    row satisfies it. Rows are keyed by ``(name, variant)`` and a variant is an
    int, so looking such a token up variant-first can only miss, which reported
    every collapsed priority entry as matching nothing and left a role that
    really had no row indistinguishable from one with a full set.

    Args:
        tokens: the raw ``whitelist``/``priority`` value.
        modes: the run's selected deploy modes.
        tor_mode: the run's tor axis.
        distros: the distro pool the run draws from.
        filesystems: the filesystem pool the run draws from.
        lifecycles: the run's lifecycle envelope.
        label: the input's name, for the messages.

    Returns:
        ``(errors, warnings)``.
    """
    pins = selection.parse_list(display_names().decode_list(tokens))
    if not pins:
        return [], []

    rows = {
        (row["name"], row["variant"]): query.row_modes(row, modes)
        for row in query.discover_rows(
            modes, whitelist=selection.names(pins), lifecycles=lifecycles
        )
    }
    discovered_apps = {app for app, _variant in rows}
    declared = get_variants()
    errors: list[str] = []
    warnings: list[str] = []
    for pin in pins:
        token = selection.describe(pin)
        if pin.app not in discovered_apps:
            warnings.append(
                f"{label}: {token!r} matches no discovered row "
                f"(no row in this run's mode and lifecycle envelope)"
            )
            continue
        if not pin.pinned:
            continue
        variants = pin.variants or (None,)
        for variant in variants:
            offered = rows.get((pin.app, variant))
            if offered is None:
                count = len(declared.get(pin.app) or [])
                reason = (
                    f"role declares {count} variant(s)"
                    if pin.variants
                    else "no row in this run's mode and lifecycle envelope"
                )
                message = f"{label}: {token!r} matches no discovered row ({reason})"
                (errors if pin.pinned else warnings).append(message)
                continue
            try:
                axes.check_pins(
                    pin.app,
                    "" if variant is None else str(variant),
                    offered,
                    pin_mode=pin.mode,
                    pin_tor=pin.tor,
                    pin_distro=pin.distro,
                    pin_filesystem=pin.filesystem,
                    capable=tor.tor_capable(pin.app, variant, declared),
                    tor_mode=tor_mode,
                    distros=distros,
                    filesystems=filesystems,
                )
            except SystemExit as refusal:
                errors.append(f"{label}: {token!r} {str(refusal).split(': ', 1)[-1]}")
    return errors, warnings


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(
        description="Validate a run's selection inputs against this branch."
    )
    parser.add_argument("--whitelist", default="")
    parser.add_argument("--priority", default="")
    parser.add_argument("--modes", default=query.ALL_MODES)
    parser.add_argument("--tor", default=None)
    parser.add_argument("--distros", default="")
    parser.add_argument("--filesystem", default="")
    parser.add_argument("--lifecycles", default="")
    args = parser.parse_args(argv)

    modes = query.resolve_modes(args.modes)
    tor_mode = tor.resolve_tor_mode(args.tor)
    distros = pools.resolve_distros(args.distros)
    filesystems = pools.resolve_filesystems(args.filesystem)

    errors: list[str] = []
    warnings: list[str] = []
    for label, tokens in (("whitelist", args.whitelist), ("priority", args.priority)):
        found, warned = problems(
            tokens,
            modes=modes,
            tor_mode=tor_mode,
            distros=distros,
            filesystems=filesystems,
            lifecycles=args.lifecycles,
            label=label,
        )
        errors += found
        warnings += warned

    for warning in warnings:
        print(f"::warning::{warning}")
    for error in errors:
        print(f"::error::{error}", file=sys.stderr)
    if errors:
        print(
            f"\n{len(errors)} unusable selection(s). Every one of them would abort a "
            f"chunk's discovery, so the run is refused here instead.",
            file=sys.stderr,
        )
        return 1
    print("Selection inputs are valid for this branch.")
    return 0


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