#!/usr/bin/env bash
# SPDX-License-Identifier: LicenseRef-Starship-1.0
# Copyright (c) 2023-2026 Robert A. James
# check_protocol.sh [<rev>] -- does <rev> (default HEAD) carry the developer protocol's evidence
# for its own tree? (#135; Captain Bob, 2026-11-07: "the protocol evidence can be submitted in
# the PR"). Run by .gitea/workflows/acceptance.yml on the pull request's head, in the repository
# the current directory is in. Tests: scripts/test_check_protocol.sh.
#
# The evidence is a logs/<TS>/PROTOCOL.md, as `scripts/nightly.sh protocol` writes it, naming
#   - Commit: <the commit the stages ran on>
#   - Tree: clean
#   - Result: PASS
# It is for <rev>'s tree when that commit differs from <rev> only in the evidence itself --
# logs/ and experiments/bare_metal/runs/, which a developer commits after the run. Any other
# change since is a change the protocol did not see: the evidence is stale, and the protocol is run
# again (a repair means rerunning from the top).
#
# Exit 0 with the protocol that counts; 1 "refused", with why; 2 on a usage error.
set -uo pipefail
rev=${1:-HEAD}
EVIDENCE=(':(exclude)logs' ':(exclude)experiments/bare_metal/runs')

refuse() { echo "check_protocol: refused -- $*" >&2; exit 1; }
git rev-parse --verify -q "$rev^{commit}" >/dev/null || { echo "check_protocol: no commit $rev" >&2; exit 2; }
head=$(git rev-parse "$rev^{commit}")

mapfile -t protocols < <(git ls-tree -r --name-only "$head" -- logs | grep -E '^logs/[^/]+/PROTOCOL\.md$' | sort -r)
[ ${#protocols[@]} -gt 0 ] || refuse "${head:0:8} carries no logs/<TS>/PROTOCOL.md: run scripts/nightly.sh protocol and commit its logs"

why=()
for p in "${protocols[@]}"; do
    body=$(git show "$head:$p")
    commit=$(sed -n 's/^- Commit: *\([0-9a-f]\{40\}\) *$/\1/p' <<<"$body" | head -1)
    tree=$(sed -n 's/^- Tree: *\([a-z]*\) *$/\1/p' <<<"$body" | head -1)
    result=$(sed -n 's/^- Result: *\([A-Z]*\) *$/\1/p' <<<"$body" | head -1)
    if [ -z "$commit" ] || ! git cat-file -e "$commit^{commit}" 2>/dev/null; then
        why+=("$p: names no commit this repository has (${commit:-none}).")
    elif [ "$result" != PASS ]; then
        why+=("$p: the protocol for ${commit:0:8} did not pass (${result:-no result}).")
    elif [ "$tree" != clean ]; then
        why+=("$p: the protocol for ${commit:0:8} ran on a tree that was ${tree:-not said to be clean}.")
    elif ! git diff --quiet "$commit" "$head" -- . "${EVIDENCE[@]}"; then
        why+=("$p: stale -- ${head:0:8} differs from ${commit:0:8} outside logs/ and experiments/bare_metal/runs/: $(git diff --name-only "$commit" "$head" -- . "${EVIDENCE[@]}" | head -3 | tr '\n' ' ')")
    else
        echo "check_protocol: ${head:0:8} carries $p -- the protocol passed on ${commit:0:8}, the same tree but for its evidence"
        exit 0
    fi
done
printf '  %s\n' "${why[@]}" >&2
refuse "no PROTOCOL.md in ${head:0:8} is a passing protocol for its tree"