#!/usr/bin/env bash
# gstack-brain-enqueue — write a path record into the GBrain sync spool.
#
# Usage:
#   gstack-brain-enqueue <file-path>
#
# Called by writer scripts (gstack-learnings-log, gstack-timeline-log, etc.)
# after their local write. Fire-and-forget; failures are silent (never blocks
# the writer). The spool is drained by `gstack-brain-sync --once` invoked from
# the preamble at skill START and END boundaries.
#
# No-op when:
#   - artifacts_sync_mode is off (the default)
#   - ~/.gstack/.git doesn't exist (feature not initialized)
#   - <file-path> matches a line in ~/.gstack/.brain-skip.txt
#
# Env:
#   GSTACK_HOME — override ~/.gstack state directory (aligns with writers).
#                 Tests use GSTACK_HOME=/tmp/test-$$ for isolation.
#
# Concurrency: maildir-style spool — one FILE per record under
# .brain-queue.d/, created via tmp-file + atomic rename. Writer and drainer
# never share an inode, so there is no append/rewrite race by construction
# (the legacy single-file .brain-queue.jsonl append could race the drain's
# rewrite). Filenames are <epoch>-<pid>-<uniq>.json, so a sorted listing is
# chronological.

# No `-e` — writer shims rely on this never failing loudly.
set -uo pipefail

FILE="${1:-}"
[ -z "$FILE" ] && exit 0

GSTACK_HOME="${GSTACK_HOME:-$HOME/.gstack}"
SPOOL="$GSTACK_HOME/.brain-queue.d"
SKIP_FILE="$GSTACK_HOME/.brain-skip.txt"

# Fast exits: no git repo, no sync.
[ ! -d "$GSTACK_HOME/.git" ] && exit 0

# Check sync mode. off → silent no-op.
SCRIPT_DIR="$(cd "$(dirname "$0")" 2>/dev/null && pwd)"
MODE=$("$SCRIPT_DIR/gstack-config" get artifacts_sync_mode 2>/dev/null || echo off)
[ "$MODE" = "off" ] && exit 0

# User-maintained skip list (for secret-scan false positives).
if [ -f "$SKIP_FILE" ]; then
  if grep -Fxq "$FILE" "$SKIP_FILE" 2>/dev/null; then
    exit 0
  fi
fi

# JSON-escape the file path (backslash + quotes only; paths shouldn't have other specials).
ESC_FILE=$(printf '%s' "$FILE" | sed 's/\\/\\\\/g; s/"/\\"/g')
TS=$(date -u +%Y-%m-%dT%H:%M:%SZ 2>/dev/null || echo "")

# One spool file per record: tmp write + atomic rename. Any failure exits 0
# silently (fire-and-forget contract), cleaning up the tmp file.
mkdir -p "$SPOOL" 2>/dev/null || exit 0
TMP="$SPOOL/.tmp-$$-$RANDOM"
printf '{"file":"%s","ts":"%s"}\n' "$ESC_FILE" "$TS" > "$TMP" 2>/dev/null || { rm -f "$TMP" 2>/dev/null; exit 0; }
mv -f "$TMP" "$SPOOL/$(date +%s)-$$-$RANDOM.json" 2>/dev/null || rm -f "$TMP" 2>/dev/null

exit 0