#!/usr/bin/env bash
# ci/lib.sh — shared helpers for the merge-gate scripts.
# Sourced by every ci/*.sh; never executed directly.
#
# Conventions:
#   - All scripts: `set -euo pipefail`.
#   - Log to stderr; machine-readable output (e.g. requirement lists) to stdout.
#   - Exit codes: 0 = pass, 1 = fail (gate blocks), 3 = SKIPPED/not-run
#     (cluster-gated stage with no cluster — NOT a pass, NOT a fail).
set -euo pipefail

# --- Paths -------------------------------------------------------------------
# CI_DIR = this ci/ directory (always the real script location). REPO_ROOT = its
# parent (impl repo root) by default, but OVERRIDABLE via the environment so the
# scripts can be pointed at a throwaway git repo under test (see ci/tests/) without
# copying them out of the tree. CI and normal runs leave it unset -> unchanged.
CI_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
: "${REPO_ROOT:=$(cd "${CI_DIR}/.." && pwd)}"
# shellcheck disable=SC1091
source "${CI_DIR}/versions.env"

# --- Integration points (other agents' entrypoints) --------------------------
# These are the seams this gate depends on. Each has an env override so the PM /
# owning agent can reconcile the real entrypoint at integration WITHOUT editing
# these scripts. Defaults are this workstream's *assumptions* — see README.
: "${CATALOG_DIR:=${REPO_ROOT}/catalog}"                       # ServiceDefinition sources
: "${SCHEMAS_DIR:=${REPO_ROOT}/schemas}"                       # owned by T-0.3 (schema + renderer contract)
: "${KYVERNO_POLICY_DIR:=${REPO_ROOT}/platform/kyverno}"       # owned by T-0.5 (L0 Kyverno policies + tests)
: "${CONFORMANCE_DIR:=${REPO_ROOT}/conformance}"               # owned by T-0.4 (Chainsaw harness + coverage)
# Commands (overridable). Defaults documented in ci/README.md.
: "${SCHEMA_VALIDATE_CMD:=${SCHEMAS_DIR}/validate.sh}"          # ASSUMED: validates catalog/*.yaml against the ServiceDefinition schema
: "${CONFORMANCE_CMD:=${CONFORMANCE_DIR}/run.sh}"              # ASSUMED: single-command conformance runner (R-TEST-02)

# --- Artifact locations (git-ignored: see .gitignore) ------------------------
: "${RESULTS_DIR:=${REPO_ROOT}/results}"    # JUnit XML lands here
: "${REPORTS_DIR:=${REPO_ROOT}/reports}"    # requirement-coverage report lands here
: "${JUNIT_DIR:=${RESULTS_DIR}/junit}"
: "${COVERAGE_DIR:=${REPORTS_DIR}/coverage}"

# --- Logging -----------------------------------------------------------------
_is_tty() { [ -t 2 ]; }
if _is_tty; then C_RED=$'\033[31m'; C_GRN=$'\033[32m'; C_YEL=$'\033[33m'; C_BLU=$'\033[34m'; C_DIM=$'\033[2m'; C_RST=$'\033[0m'
else C_RED=""; C_GRN=""; C_YEL=""; C_BLU=""; C_DIM=""; C_RST=""; fi

log()  { printf '%s[gate]%s %s\n' "$C_BLU" "$C_RST" "$*" >&2; }
ok()   { printf '%s[ ok ]%s %s\n' "$C_GRN" "$C_RST" "$*" >&2; }
warn() { printf '%s[warn]%s %s\n' "$C_YEL" "$C_RST" "$*" >&2; }
err()  { printf '%s[fail]%s %s\n' "$C_RED" "$C_RST" "$*" >&2; }
skip() { printf '%s[skip]%s %s\n' "$C_YEL" "$C_RST" "$*" >&2; }
die()  { err "$*"; exit 1; }

# Emit a GitHub/Gitea-Actions step-summary line if running in Actions.
summary() { [ -n "${GITHUB_STEP_SUMMARY:-}" ] && printf '%s\n' "$*" >> "$GITHUB_STEP_SUMMARY" || true; }

# --- Tooling -----------------------------------------------------------------
have() { command -v "$1" >/dev/null 2>&1; }

# require_tool <bin> <hint> — fail with an actionable message if missing.
require_tool() {
  have "$1" && return 0
  die "required tool '$1' not found. $2"
}

# entrypoint_ready <path-or-cmd> — returns 0 only if it exists AND is runnable.
# Used to distinguish 'other agent hasn't delivered yet / non-executable stub'
# (-> SKIP) from a wired entrypoint that genuinely fails (-> FAIL). A file that
# exists but isn't executable counts as NOT ready (unwired), not a failure.
entrypoint_ready() {
  local ep="$1"
  have "$ep" && return 0        # a bare command on PATH
  [ -f "$ep" ] && [ -x "$ep" ] && return 0   # an executable file
  return 1
}

# truthy <value> — the ONE place the repo's "is this switch on" spelling lives, so
# CLUSTER_AVAILABLE / REQUIRE_CLUSTER_TESTS / REQUIRE_SPEC_VERIFICATION / GATE_STRICT_SKIPS
# all agree. Anything not listed is OFF, and that direction matters: a misspelled value
# (CLUSTER_AVAILABLE=ture, REQUIRE_SPEC_VERIFICATION=yeah) leaves the guard OFF rather than
# silently declaring a capability "available", so a typo can only make the gate stricter about
# what it claims to have verified, never looser.
truthy() {
  case "${1:-}" in
    true|TRUE|True|1|yes|YES|y|on|ON) return 0 ;;
    *) return 1 ;;
  esac
}

# --- Cluster detection (drives SKIP vs run for L2/L3) -------------------------
# A cluster is 'available' only if explicitly DECLARED. We NEVER auto-assume a
# cluster in Phase 0 — silence means SKIP, not pass (HARD RULE 4).
#   CLUSTER_AVAILABLE=true   -> L2/L3 run and are REQUIRED green
#   CLUSTER_AVAILABLE=false/unset -> L2/L3 SKIP (reported, never faked green)
# That DECLARATION is what makes an L2/L3 skip different IN KIND from every other skip —
# see "WHICH SKIPS BLOCK, AND WHY" in ci/gate.sh.
cluster_available() { truthy "${CLUSTER_AVAILABLE:-false}"; }

# --- Skip strictness: is this a CI runner, or a workstation? -------------------
# A SKIPPED stage is never green anywhere (HARD RULE 4), but its SEVERITY differs:
#
#   CI       the pinned toolchain is installed by .gitea/workflows/scripts/install-tools.sh
#            before the gate runs, and every seam is on `main`. A stage that skips here is a
#            DEFECT (a tool dropped from the installer, a seam that went unwired) -> BLOCK.
#   local    a missing pinned tool is a real, ordinary local condition -> the gate reports
#            UNDETERMINED (exit 3): not green, not a pass, but distinguishable from a red.
#
# HOW STRICTNESS IS DECIDED — DECLARED first, detected only as a fallback:
#
#   1. GATE_STRICT_SKIPS=true|false is the AUTHORITY. .gitea/workflows/gate.yml sets `true` on
#      the gate step, so on the one CI runner that matters strictness is a DECLARATION IN THE
#      WORKFLOW, not an inference: the environment that KNOWS it is CI says so, and no
#      env-var sniffing can get it wrong.
#   2. `auto` (the default — anywhere the caller said nothing) falls back to GITHUB_ACTIONS /
#      CI, which are set by the runner ITSELF (Gitea's act_runner, as well as GitHub). We do
#      NOT sniff hostnames, paths or tool availability: a heuristic that guesses "this looks
#      like CI" is exactly the unreliable inference this gate must not contain.
#
# WHY A WRONG ANSWER CANNOT FAIL OPEN: both branches are non-zero and NEITHER is a pass. A CI
# run misread as local yields UNDETERMINED (exit 3) instead of BLOCKED (exit 1) — that still
# fails the job unless its caller explicitly tolerates 3, which gate.yml does only knowingly
# and only for the one declared-environmental skip (see its comment). A workstation misread as
# CI yields BLOCKED instead of UNDETERMINED — harsher, never looser. Set GATE_STRICT_SKIPS=true
# locally to rehearse CI strictness.
: "${GATE_STRICT_SKIPS:=auto}"
strict_skips() {
  case "$GATE_STRICT_SKIPS" in
    auto) truthy "${GITHUB_ACTIONS:-}" || truthy "${CI:-}" ;;
    *)    truthy "$GATE_STRICT_SKIPS" ;;
  esac
}

mkartifacts() { mkdir -p "$JUNIT_DIR" "$COVERAGE_DIR"; }

# --- Offline (L0/L1) per-check step summary -----------------------------------
# conformance/lib/run_l1_offline.py writes one Markdown line per check it executed to
# conformance/_artifacts/offline-summary.md. Splice those into $GITHUB_STEP_SUMMARY so the
# gate's output still NAMES every check that ran and its verdict.
#
# WHY THIS EXISTS: ci/l0.sh used to carry a hand-written stage per whole-repo check, each with
# its own `summary "- subst-safety: **passed**"` line. Those stages are gone (the tests declare
# `conformance.home.k3s/scope: whole-repo` instead and the runner unions them in), so the
# naming is generated for EVERY offline check rather than for the three that had a stage.
: "${OFFLINE_SUMMARY_FILE:=${CONFORMANCE_DIR}/_artifacts/offline-summary.md}"
emit_offline_summary() {
  local f="${1:-$OFFLINE_SUMMARY_FILE}" line
  [ -f "$f" ] || return 0
  while IFS= read -r line; do
    [ -n "$line" ] && summary "  $line"
  done < "$f"
  return 0
}

# --- Touched-requirement subset (R-TEST-03 input) ----------------------------
# Sets: TOUCHED_RC (0 ok / 3 not determinable), TOUCHED_REQS[] and REQ_ARGS[]
# (ready to splice into a conformance/run.sh invocation).
#
# ci/touched-requirements.sh exits 3 — LOUDLY — when it cannot establish a reliable
# diff base, instead of the old silent degradation to an empty set. An empty set
# means run.sh gets no `--requirements`, which means its coverage `--require` gate
# never runs; treating "could not determine" as "nothing touched" is precisely the
# false green this helper exists to prevent. A stage still runs its FULL layer in
# that case (a superset, so nothing goes untested), but says plainly that the
# SCOPED check did not happen; ci/gate.sh turns that into an UNDECIDED decision.
load_touched_requirements() {
  local out rc=0
  out="$("${CI_DIR}/touched-requirements.sh")" || rc=$?
  TOUCHED_RC=$rc
  TOUCHED_REQS=()
  # `if`, not `[ ... ] && ...`: under `set -e` a false AND-list is the caller's last
  # command status and would abort the stage script on an EMPTY touched set.
  if [ -n "$out" ]; then mapfile -t TOUCHED_REQS <<< "$out"; fi
  REQ_ARGS=()
  if [ "$rc" -eq 3 ]; then
    warn "touched-requirement subset UNDETERMINED (reason logged above)."
    warn "  Running the FULL layer as a superset sanity net; the SCOPED R-TEST-03"
    warn "  coverage check is NOT performed here — ci/gate.sh reports that as UNDECIDED."
  elif [ "$rc" -ne 0 ]; then
    # Any OTHER non-zero exit means the subset is UNUSABLE, not empty (today: a
    # path->requirement map that cannot classify a changed path, once that map fails closed).
    # The FULL layer still runs here as a superset — nothing goes untested — but this stage must
    # not claim the SCOPED check happened, and ci/gate.sh turns the same exit into a BLOCKED
    # merge decision. Wording carried over from the unlanded fix/touched-requirements-fail-closed
    # (47068ee), whose gate-side half this branch lands.
    warn "touched-requirements.sh exited ${rc} (subset UNUSABLE — see its output above)."
    warn "  Running the FULL layer as a superset; the SCOPED R-TEST-03 check did NOT happen."
    warn "  ci/gate.sh BLOCKS the merge on this: fix the path->requirement map in"
    warn "  ci/touched-requirements.sh so every changed path is classified."
  elif [ "${#TOUCHED_REQS[@]}" -gt 0 ]; then
    log "touched requirements: ${TOUCHED_REQS[*]}"
    REQ_ARGS=(--requirements "$(IFS=,; echo "${TOUCHED_REQS[*]}")")
  else
    log "empty touched-requirement set (base WAS established) — running the full layer."
  fi
  return 0
}