#!/usr/bin/env bash
# Shared helpers for the SHOC PR review runner. Sourced by every script.

set -euo pipefail

: "${WORKSPACE_DIR:?WORKSPACE_DIR must be set}"
ARTIFACTS_DIR="${ARTIFACTS_DIR:-$WORKSPACE_DIR/artifacts}"
# The gate table records what actually executed, so it must NOT live inside the
# workspace: the build gates execute PR-authored code (npm/dotnet lifecycle
# scripts), and anything under the workspace is trivially writable by that code.
# STATE_DIR defaults outside the workspace; duplicate keys are rejected at read
# time so a tampered table fails the run instead of forging a PASS.
STATE_DIR="${STATE_DIR:-${RUNNER_TEMP:-$WORKSPACE_DIR}/runner-state}"
GATE_STATUS_FILE="${GATE_STATUS_FILE:-$STATE_DIR/gate-status.tsv}"
LOG_DIR="${LOG_DIR:-$ARTIFACTS_DIR/logs}"

mkdir -p "$ARTIFACTS_DIR" "$LOG_DIR" "$STATE_DIR"
chmod 700 "$STATE_DIR" 2>/dev/null || true

log() { printf '%s %s\n' "$(date -u +%H:%M:%S)" "$*" >&2; }

die() {
  log "ERROR: $*"
  exit 1
}

# record_gate <key> <PASS|FAIL|NOT_APPLICABLE|NOT_RUN|BLOCKED> [detail]
# Appends to the machine-readable gate table consumed by evidence generation and
# output validation. A gate is only ever PASS because the command that proves it
# actually ran and exited 0.
record_gate() {
  local key="$1" status="$2" detail="${3:-}"
  case "$status" in
    PASS|FAIL|NOT_APPLICABLE|NOT_RUN|BLOCKED) ;;
    *) die "invalid gate status '$status' for $key" ;;
  esac
  # Strip control characters from the detail so nothing can forge table rows.
  detail="$(printf '%s' "$detail" | tr -d '\000-\037')"
  printf '%s\t%s\t%s\n' "$key" "$status" "$detail" >>"$GATE_STATUS_FILE"
  log "gate $key = $status${detail:+ ($detail)}"
}

# run_gate <key> <logfile-basename> <cmd...>
# Runs the command, captures combined output to the log, records PASS/FAIL.
# Returns the command's exit code so callers can decide whether to block
# dependent gates.
#
# The command may be PR-authored code, so the Actions runner-command channels
# are removed from its environment: without them it cannot append to
# $GITHUB_ENV / $GITHUB_PATH to poison later steps, or write step outputs.
run_gate() {
  local key="$1" logname="$2"
  shift 2
  local logfile="$LOG_DIR/$logname"
  log "running gate $key: $*"
  local rc=0
  # RUNNER_TEMP is unset too: the Actions file commands live at
  # $RUNNER_TEMP/_runner_file_commands/*, so leaving it set would let the build
  # re-acquire the $GITHUB_ENV / $GITHUB_PATH channel by globbing that directory.
  env -u GITHUB_ENV -u GITHUB_PATH -u GITHUB_OUTPUT -u GITHUB_STATE \
      -u GITHUB_STEP_SUMMARY -u ACTIONS_RUNTIME_TOKEN -u ACTIONS_ID_TOKEN_REQUEST_TOKEN \
      -u ACTIONS_ID_TOKEN_REQUEST_URL -u RUNNER_TEMP -u STATE_DIR -u GATE_STATUS_FILE \
      "$@" >>"$logfile" 2>&1 || rc=$?
  if [ "$rc" -eq 0 ]; then
    record_gate "$key" PASS "log: logs/$logname"
  else
    record_gate "$key" FAIL "exit $rc, log: logs/$logname"
  fi
  return "$rc"
}

# assert_gate_table_intact
# Fails closed if any gate key appears more than once. The runner records each
# key exactly once, so a duplicate means someone else wrote to the table. This
# catches both override-by-append and pre-seeding (writing a forged PASS for a
# key before the runner records the genuine result): either way the genuine row
# lands alongside the forged one and the duplicate is detected.
# MUST be called before any gate_status() read that informs a decision.
assert_gate_table_intact() {
  [ -f "$GATE_STATUS_FILE" ] || return 0
  local dupes
  dupes="$(cut -f1 "$GATE_STATUS_FILE" | sort | uniq -d)"
  if [ -n "$dupes" ]; then
    log "duplicate gate keys detected (table tampering or a script bug):"
    printf '%s\n' "$dupes" >&2
    die "gate table integrity check failed"
  fi
}

# gate_status <key> -> prints the recorded status, or NOT_RUN if absent.
# First-wins: the runner records each key once, so an appended row can never
# override a genuine result even if the integrity check is bypassed.
gate_status() {
  local key="$1"
  awk -F'\t' -v k="$key" '$1==k && !seen {s=$2; seen=1} END{print (seen?s:"NOT_RUN")}' \
    "$GATE_STATUS_FILE" 2>/dev/null || echo "NOT_RUN"
}

# require_env <name>...
require_env() {
  local n
  for n in "$@"; do
    [ -n "${!n:-}" ] || die "required environment variable $n is not set"
  done
}