#!/usr/bin/env bash
# Usage-error contract for pr-close.sh (R1/R4, 2026-08-28).
#
# R4: usage errors print to STDERR and exit 2, distinct from provider,
# credential, and verification failures (exit 1). R1: -b/--body is the
# canonical comment flag; -c/--comment remains a compatible alias.
# The comment is OPTIONAL here (an issue may close without one), so unlike
# issue-comment there is no missing-comment arm.
#
# Arms:
#   1. --help and -h exit 0 and print usage.
#   2. Unknown option exits 2 with the message on stderr.
#   3. Missing required -i exits 2 (stderr).
#   4. A value-less flag (-i -b -c and long forms) exits 2 (stderr).
#   5. -b and -c both pass parsing (sandboxed runner: the run then fails
#      at credential resolution, nonzero and NOT 2) — no real token is
#      ever read and no provider is contacted.
#   6. No arm performs any provider request (PATH shims record every
#      invocation; the probe log must stay empty).
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
WORK_DIR="${MOSAIC_TEST_WORK_DIR:-$PWD/.mosaic-test-work/pr-close-usage}"
BIN_DIR="$WORK_DIR/bin"
PROBE_LOG="$WORK_DIR/provider-probes.log"
OUT_FILE="$WORK_DIR/out.log"
ERR_FILE="$WORK_DIR/err.log"

cleanup() {
    rm -rf "$WORK_DIR"
}
trap cleanup EXIT

mkdir -p "$BIN_DIR"
: > "$PROBE_LOG"

# Unlike the issue suites, these stubs FAIL (exit 99): pr-close has an
# API fallback that treats a successful curl as a closed PR, so exit-0
# stubs would let the sandbox arms "succeed" (measured 2026-08-28).
for tool in gh tea curl; do
    cat > "$BIN_DIR/$tool" <<STUB
#!/usr/bin/env bash
echo "$tool \$*" >> "$PROBE_LOG"
exit 99
STUB
    chmod +x "$BIN_DIR/$tool"
done

run_wrapper() {
    ( cd "$WORK_DIR" && PATH="$BIN_DIR:$PATH" "$SCRIPT_DIR/pr-close.sh" "$@" )
}

# Hermetic variant: neutralizes every identity/credential source the wrapper
# consults so parse-acceptance arms fail at credential resolution in ANY cwd
# repo (see test-issue-comment-usage-contract.sh for the measured incident).
run_wrapper_sandboxed() {
    mkdir -p "$WORK_DIR/home" "$WORK_DIR/xdg"
    (
        cd "$WORK_DIR"
        PATH="$BIN_DIR:$PATH" HOME="$WORK_DIR/home" XDG_CONFIG_HOME="$WORK_DIR/xdg" \
            MOSAIC_GIT_IDENTITY="" MOSAIC_BRAIN_HOME="" \
            "$SCRIPT_DIR/pr-close.sh" "$@"
    )
}

fail() {
    echo "FAIL: $*" >&2
    echo "--- stderr ---" >&2
    cat "$ERR_FILE" >&2
    exit 1
}

expect_rc() { # expect_rc <want> <desc> <args...>
    local want="$1" desc="$2" rc=0
    shift 2
    run_wrapper "$@" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
    [[ "$rc" -eq "$want" ]] || fail "$desc: rc=$rc, want $want"
}

expect_stderr() { # expect_stderr <pattern> <desc>
    grep -q "$1" "$ERR_FILE" || fail "$2: stderr missing '$1'"
}

# 1. Help exits 0 and prints usage.
expect_rc 0 "--help exits 0" --help
grep -q "Usage: pr-close.sh" "$OUT_FILE" || fail "--help did not print usage"
expect_rc 0 "-h exits 0" -h

# 2. Unknown option: rc 2, stderr.
expect_rc 2 "unknown option exits 2" --bogus
expect_stderr "unknown option" "unknown option names itself on stderr"

# 3. Missing required PR number: rc 2, stderr.
expect_rc 2 "missing -n exits 2"
expect_stderr "PR number is required" "missing -n message on stderr"

# 4. Value-less flags: rc 2 with "requires a value" on stderr.
for flag in -n -b -c --number --body --comment; do
    expect_rc 2 "value-less $flag exits 2" "$flag"
    expect_stderr "requires a value" "value-less $flag message on stderr"
done

# 4a. An option-like value is a MISSING value, not a value (codex PR #1464:
# -b --help previously consumed --help as the body and performed the write).
expect_rc 2 "option-like value rejected" -n 5 -b --help
expect_rc 2 "short flag value rejected" -n 5 -b -h
expect_stderr "requires a value" "short flag value message on stderr"
expect_stderr "requires a value" "option-like value message on stderr"

# 4b. Parser-failure arms (1-4) must have performed ZERO provider contact.
if [[ -s "$PROBE_LOG" ]]; then
    echo "FAIL: a parser-failure arm contacted a provider:" >&2
    cat "$PROBE_LOG" >&2
    exit 1
fi

# 5. Alias acceptance under the sandbox: both -b and -c carry a value past
#    parsing; the run fails at credential resolution nonzero and NOT 2.
for flag in -b -c; do
    rc=0
    run_wrapper_sandboxed -n 5 "$flag" "closing note" >"$OUT_FILE" 2>"$ERR_FILE" || rc=$?
    [[ "$rc" -ne 0 ]] || fail "$flag arm unexpectedly succeeded in the sandbox"
    [[ "$rc" -ne 2 ]] || fail "$flag arm misclassified credential failure as a usage error"
done

# 6. Post-sandbox provider assertions are intentionally NOT applied here:
# pr-close's gitea path attempts a tea WRITE (tea pr comment) when a
# comment parses, then falls back to the API. Hermeticity for this
# wrapper comes from the FAILING stubs (exit 99), not from non-contact —
# the arm above proves only parse acceptance and non-usage classification.
# Parser-failure arms (1-4) remain zero-contact (asserted at 4b).

echo "pr-close.sh usage-contract regression passed (R1/R4)"