#!/usr/bin/env python3
"""deploy_qualify.py — read the CI qualification status for one commit.

Called by .gitea/workflows/deploy.yml (kept out of the YAML so the workflow
has no embedded multi-line scripts — a YAML block-scalar indentation hazard).

Prints one of: success | failure | pending
Exit code 0 always (the shell decides what to do with the verdict).

RELEASE-SAFETY HARDENING (2026-09-13, after red-CI promotions 0.66.28/29):
the verdict is the AND of two independent legs —
  1. required-checks context (newest observation for this exact SHA);
  2. the latest COMPLETED ci.yml@refs/heads/master run for this exact SHA,
     every job concluded success (branch+tag fan-out resolved by path;
     jobs envelope unwrapped — no aggregate-commit-status fallback, the
     exact bug class verify.py hit in W/R-v0.3).
Any disagreement, pending, or missing evidence → pending/failure.
FAIL-CLOSED: not verified → not deployable.
"""

from __future__ import annotations

import json
import os
import sys
import urllib.request
import sys as _sys
_SCRIPT_DIR = str(__import__('pathlib').Path(__file__).resolve().parent)
if _SCRIPT_DIR not in _sys.path:
    _sys.path.insert(0, _SCRIPT_DIR)
import gitea_auth

REQUIRED_CONTEXT = "CI Pipeline / required-checks"
CI_WORKFLOW_PATH = "ci.yml@refs/heads/master"


# ── pure verdict logic (unit-tested; fixtures from the real incidents) ────

def required_check_verdict(statuses: list[dict]) -> str:
    """Newest non-skipped required-checks observation for the SHA.
    Missing → pending. Newest wins (stale success never overrides a newer
    failure, and vice versa)."""
    candidates = [
        s for s in statuses
        if str(s.get("context", "")).startswith(REQUIRED_CONTEXT)
        and s.get("status") != "skipped"
    ]
    if not candidates:
        return "pending"
    newest = max(candidates, key=lambda s: str(s.get("created_at", "")))
    return str(newest.get("status", "pending"))


def independent_jobs_verdict(runs: list[dict], jobs_fetch, sha: str = "") -> str:
    """Latest COMPLETED ci.yml@refs/heads/master run for the exact SHA:
    every job must conclude success. Fan-out-safe (tag runs and sibling
    workflows are excluded by path); the run is resolved by head_sha, never
    by 'latest branch state'. Missing run → pending. Any non-success
    conclusion → failure."""
    mine = [r for r in runs if r.get("path") == CI_WORKFLOW_PATH]
    if sha:
        mine = [r for r in mine if str(r.get("head_sha", "")) == sha]
    completed = [r for r in mine if r.get("status") == "completed"]
    if not completed:
        return "pending"
    latest = max(completed, key=lambda r: str(r.get("created_at", "") or r.get("run_started_at", "")))
    jobs = jobs_fetch(latest.get("id"))
    if jobs is None:
        return "pending"  # jobs probe failed → not verified
    if not jobs:
        return "pending"  # no jobs visible → cannot verify
    for j in jobs:
        if j.get("conclusion") != "success":
            return "failure"
    return "success"


def combine(a: str, b: str) -> str:
    """Fail-closed conjunction: any failure → failure; any pending → pending;
    success only when BOTH legs are success."""
    if "failure" in (a, b):
        return "failure"
    if "pending" in (a, b):
        return "pending"
    return "success"


def qualify(statuses: list[dict], runs: list[dict], jobs_fetch, sha: str = "") -> str:
    return combine(required_check_verdict(statuses),
                   independent_jobs_verdict(runs, jobs_fetch, sha=sha))


# ── API fetches (thin; injectable in tests) ───────────────────────────────

def _get_json(url: str, token: str, timeout: int = 30):
    req = urllib.request.Request(url, headers={"Authorization": f"token {token}"})
    try:
        with urllib.request.urlopen(req, timeout=timeout) as r:
            return json.loads(r.read())
    except (OSError, ValueError):
        return None


def _fetch_status(server: str, repo: str, sha: str, token: str) -> list[dict] | None:
    data = _get_json(f"{server}/api/v1/repos/{repo}/commits/{sha}/status", token)
    return None if data is None else data.get("statuses", [])


def _fetch_runs(server: str, repo: str, sha: str, token: str,
                max_pages: int = 4) -> list[dict] | None:
    """H-PATCH: paginate the runs list. The repo's scheduled merge-robot
    runs flood the first page (~50 slots exhaust within hours), pushing
    older-but-relevant SHAs to later pages — the cause of the observed
    authority flapping (terminal commit read as pending). Paginate until
    the sha is found or max_pages exhausted."""
    out: list[dict] = []
    for page in range(1, max_pages + 1):
        data = _get_json(
            f"{server}/api/v1/repos/{repo}/actions/runs?limit=50&page={page}",
            token)
        if data is None:
            return None if page == 1 else (out or None)
        runs = data.get("workflow_runs", data if isinstance(data, list) else [])
        out.extend(r for r in runs if str(r.get("head_sha", "")) == sha)
        if len(runs) < 50:
            break  # exhausted
    return out


def _fetch_jobs(server: str, repo: str, run_id, token: str) -> list[dict] | None:
    data = _get_json(f"{server}/api/v1/repos/{repo}/actions/runs/{run_id}/jobs", token)
    if data is None:
        return None
    # jobs envelope unwrap (this Gitea wraps in {"jobs": [...]}; some
    # versions return a bare list) — never fall back to aggregate status
    if isinstance(data, dict):
        return data.get("jobs", [])
    return data if isinstance(data, list) else None


# ── CLI ───────────────────────────────────────────────────────────────────

def main() -> int:
    # T21.4 fix: fall back to the canonical defaults when the caller did
    # not export GITEA_SERVER/GITEA_REPO (CI always exports them; local
    # and first-class-tool consumers previously got a silent "pending"
    # verdict — a wrong answer, not a fail-closed one).
    # H-PATCH H4: the target sha arrives EXPLICITLY (--sha) from callers
    # that hold structured operation state. DEPLOY_SHA env remains only
    # for standalone/workflow backward compat — the canonical path never
    # depends on ambient env for operation identity.
    ap = __import__("argparse").ArgumentParser()
    ap.add_argument("--sha", dest="sha_arg", default=None)
    args, _unknown = ap.parse_known_args()
    server = (os.environ.get("GITEA_SERVER", "")
              or gitea_auth.DEFAULT_SERVER).rstrip("/")
    repo = os.environ.get("GITEA_REPO", "") or gitea_auth.DEFAULT_REPO
    sha = args.sha_arg or os.environ.get("DEPLOY_SHA", "")
    token = gitea_auth.get_token() if gitea_auth.has_token() else ""
    if not (server and repo and sha and token):
        print("pending")  # missing config → cannot verify → not qualified
        return 0

    statuses = _fetch_status(server, repo, sha, token)
    runs = _fetch_runs(server, repo, sha, token)
    if statuses is None or runs is None:
        # transient API/network failure → keep polling
        print("pending (probe failed)")
        return 0
    jobs_fetch = lambda run_id: _fetch_jobs(server, repo, run_id, token)  # noqa: E731
    verdict = qualify(statuses, runs, jobs_fetch, sha=sha)
    print(verdict)
    return 0


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