#!/usr/bin/env bash
# ci/tests/approval-override.test.sh — proves ci/approval-override.py selects the override it
# claims to select, and REJECTS the ones it claims to reject.
#
# This parser decides whether a human review requirement gets waived. Every rule in it exists
# because the obvious implementation ("does the body contain the directive?") is wrong in a way
# that is invisible until abused: a quoted directive would re-arm an override, a bare directive
# would waive review with no stated reason, and an override posted against commit A would go on
# covering commit B forever. A guard is worth nothing until somebody has watched it refuse, which
# is the same reasoning as ci/tests/decisions-log.test.sh one layer up.
#
# The parser is pure and offline BY DESIGN — authorisation (the live permission lookup) lives in
# ci/approval-policy.sh, which cannot be tested without Gitea. That split is what makes this file
# possible, and it is also why a green run here does NOT prove the stage authorises correctly.
set -uo pipefail
CI_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
SUT="${CI_DIR}/approval-override.py"

PASS=0 FAIL=0
ok()  { printf '  ok   %s\n' "$*"; PASS=$((PASS+1)); }
bad() { printf '  FAIL %s\n' "$*"; FAIL=$((FAIL+1)); }

HEAD_TIME="2026-10-01T12:00:00Z"
AFTER="2026-10-01T12:30:00Z"
BEFORE="2026-10-01T11:30:00Z"

# run <comments-json> -> stdout of the parser (stderr is diagnostic only)
run() {
  COMMENTS_JSON="$1" HEAD_TIME="${2:-$HEAD_TIME}" DIRECTIVE="${3:-/approve-override}" \
    python3 "$SUT" 2>/dev/null
}

# comment <login> <created_at> <body>
comment() {
  python3 -c '
import json, sys
print(json.dumps([{"user": {"login": sys.argv[1]}, "created_at": sys.argv[2], "body": sys.argv[3]}]))
' "$1" "$2" "$3"
}

expect_none() {
  local label="$1" out
  out="$(run "$2")"
  if [ -z "$out" ]; then ok "$label"; else bad "$label (got: ${out})"; fi
}

expect_user() {
  local label="$1" json="$2" want="$3" out got
  out="$(run "$json")"
  got="$(cut -f1 <<<"$out")"
  if [ "$got" = "$want" ]; then ok "$label"; else bad "$label (wanted ${want}, got '${got}')"; fi
}

expect_reason() {
  local label="$1" json="$2" want="$3" out got
  out="$(run "$json")"
  got="$(cut -f3- <<<"$out")"
  if [ "$got" = "$want" ]; then ok "$label"; else bad "$label (wanted '${want}', got '${got}')"; fi
}

echo "== ci/approval-override.py"

# --- the happy path -------------------------------------------------------------------
expect_user "a directive with a reason, posted after the head commit, is selected" \
  "$(comment jakman85 "$AFTER" '/approve-override sole admin, gate is green')" jakman85

expect_reason "the reason is returned verbatim" \
  "$(comment jakman85 "$AFTER" '/approve-override sole admin, gate is green')" \
  'sole admin, gate is green'

# --- absence is a normal answer, not an error -----------------------------------------
expect_none "no comments at all" '[]'
expect_none "an ordinary comment" "$(comment jakman85 "$AFTER" 'looks good to me')"

# --- a reason is MANDATORY ------------------------------------------------------------
expect_none "a bare directive (no reason) is refused" \
  "$(comment jakman85 "$AFTER" '/approve-override')"
expect_none "a directive followed by only whitespace is refused" \
  "$(comment jakman85 "$AFTER" '/approve-override    ')"

# --- the directive must START a line --------------------------------------------------
expect_none "the directive mid-sentence does not count" \
  "$(comment jakman85 "$AFTER" 'you could just /approve-override this one')"
expect_none "a QUOTED directive does not re-arm an override" \
  "$(comment jakman85 "$AFTER" '> /approve-override quoting someone else')"
expect_user "leading whitespace before the directive is fine" \
  "$(comment jakman85 "$AFTER" '   /approve-override indented but mine')" jakman85
expect_user "the directive on a later line of a longer comment counts" \
  "$(comment jakman85 "$AFTER" 'some preamble
/approve-override the real reason here')" jakman85

# --- staleness: an override must post-date the commit it waives review on -------------
expect_none "an override OLDER than the head commit is dropped as stale" \
  "$(comment jakman85 "$BEFORE" '/approve-override stale, predates the push')"
expect_none "an override exactly AT the head commit time is dropped (strictly newer)" \
  "$(comment jakman85 "$HEAD_TIME" '/approve-override same instant')"

# --- malformed input is never a free pass --------------------------------------------
expect_none "an unreadable timestamp drops the candidate" \
  "$(comment jakman85 'not-a-date' '/approve-override bad clock')"
expect_none "a comment with no author is dropped" \
  '[{"user": {}, "created_at": "2026-10-01T12:30:00Z", "body": "/approve-override no login"}]'
expect_none "invalid JSON yields no override (and never a traceback into stdout)" \
  'this is not json'
expect_none "a JSON object instead of a list yields no override" \
  '{"user": "nope"}'

# --- latest wins ----------------------------------------------------------------------
TWO='[
  {"user": {"login": "early"},  "created_at": "2026-10-01T12:10:00Z", "body": "/approve-override first"},
  {"user": {"login": "latest"}, "created_at": "2026-10-01T12:40:00Z", "body": "/approve-override second"}
]'
expect_user "the LATEST override supersedes an earlier one" "$TWO" latest
expect_reason "and brings its own reason" "$TWO" second

# --- offsets, not just Z --------------------------------------------------------------
# Gitea emits RFC3339 WITH AN OFFSET (measured: 2026-10-01T23:09:08-05:00), not a trailing Z.
# A parser that only handles 'Z' silently drops every real override, so this case is load-bearing.
expect_user "an RFC3339 offset timestamp (-05:00), as Gitea actually emits, parses" \
  '[{"user": {"login": "jakman85"}, "created_at": "2026-10-01T08:30:00-05:00", "body": "/approve-override offset form"}]' \
  jakman85
expect_none "and an offset timestamp that is genuinely earlier is still stale" \
  '[{"user": {"login": "jakman85"}, "created_at": "2026-10-01T06:00:00-05:00", "body": "/approve-override offset, stale"}]'

# --- the directive is configurable ----------------------------------------------------
out="$(run "$(comment jakman85 "$AFTER" '/admin-waive because policy says so')" "$HEAD_TIME" '/admin-waive')"
if [ "$(cut -f1 <<<"$out")" = "jakman85" ]; then
  ok "a custom directive from the declaration is honoured"
else
  bad "a custom directive from the declaration is honoured (got '${out}')"
fi
expect_none "the default directive does not match a custom-directive comment" \
  "$(comment jakman85 "$AFTER" '/admin-waive because policy says so')"

# --- no staleness anchor: do not invent one -------------------------------------------
out="$(COMMENTS_JSON="$(comment jakman85 "$BEFORE" '/approve-override no anchor')" \
       HEAD_TIME="" DIRECTIVE=/approve-override python3 "$SUT" 2>/dev/null)"
if [ "$(cut -f1 <<<"$out")" = "jakman85" ]; then
  ok "with no HEAD_TIME the staleness test is skipped, not faked (caller blocks instead)"
else
  bad "with no HEAD_TIME the candidate should still be returned (got '${out}')"
fi

printf '\n  %d passed, %d failed\n' "$PASS" "$FAIL"
[ "$FAIL" -eq 0 ] || exit 1