#!/usr/bin/env bash
# session-start-state -- STATE.md reuse and analyze-room cache step of the
# SessionStart hook (quick 261029-lx3).
# Called by scripts/session-start as:
#   session-start-state <state|analyze> <room-dir> <script-dir>
# Stdout carries only the result text. Every log line goes to the room-local
# log file. No set -e: every step is guarded, and session-start must never
# fail because of this helper.
#
# Why: on a real room on /mnt/c, one trace of the SessionStart event showed
# scripts/analyze-room at 24,207 ms and scripts/compute-state at 9,876 ms.
# Claude Code holds the first reply until every SessionStart hook ends. Both
# results are a function of the room files, so an unchanged room can reuse
# them:
#   state    nothing changed since STATE.md was written: print STATE.md
#            instead of running compute-state (C-1). Only the
#            gsd_state_version and status lines are removed, because
#            state-write.cjs added them and compute-state never prints them
#            (DD-1). The format guard (DD-2) and the recompute triggers
#            (DD-3) decide when compute-state still runs.
#   analyze  nothing changed since the cache was written: print the cache
#            instead of running analyze-room (C-2). A failed run never
#            overwrites the cache (DD-6).
# One find call is the whole "did anything change" question. It is the find
# of scripts/on-stop-state with another reference file. It prunes every
# hidden entry, so .mindrian/ (where the cache lives) never invalidates it.

MODE="${1:-}"
ROOM_DIR="${2:-}"
SCRIPT_DIR="${3:-}"
case "$MODE" in
  state|analyze) ;;
  *) exit 2 ;;
esac
[ -d "$ROOM_DIR" ] || exit 0
[ -d "$SCRIPT_DIR" ] || exit 2

# Quick 261029-lx3, plugin-generated artifacts: the find below ignores files
# that the plugin itself rewrites at every start, because they would make the
# room look changed at every next start. The same list is in
# scripts/on-stop-state, so the Stop hook and SessionStart agree. Writers:
#   FEYNMAN.md   lib/core/feynman/timeline-runner.cjs (session-start timeline
#                refresh), scripts/vault-section-minto-generator.cjs
#   MINTO.md, BRIEF.md   scripts/vault-section-minto-generator.cjs
#   MEETINGS-INTELLIGENCE.md, action-items.md (room root only)
#                scripts/compute-meetings-intelligence, run by compute-state
#   team/TEAM-STATE.md   scripts/compute-team, run by compute-state
# ROOM.md and USER.md stay in the check. A per-meeting meetings/*/action-items.md
# stays in the check too (the list matches the room-root file by path).
# Follow-up: make these generators write only when the content changed.
# First room file newer than the reference file given as $1 (prints a path or nothing).
room_newer() { find -H "$ROOM_DIR" -mindepth 1 -name '.*' -prune -o -type f ! -name STATE.md ! -name 'STATE.md.tmp.*' ! -name FEYNMAN.md ! -name MINTO.md ! -name BRIEF.md ! -path "$ROOM_DIR/MEETINGS-INTELLIGENCE.md" ! -path "$ROOM_DIR/action-items.md" ! -path "$ROOM_DIR/team/TEAM-STATE.md" -newer "$1" -print -quit 2>/dev/null || true; }

# DD-7: one line per call. Nothing is written when the room has no .mindrian/.
log_line() {
  [ -d "${ROOM_DIR}/.mindrian" ] || return 0
  { printf '%s %s\n' "$(date -u +%FT%TZ)" "${1//[$'\n\r']/ }" >> "${ROOM_DIR}/.mindrian/session-start-state.log"; } 2>/dev/null || true
}

do_state() {
  local state_file="${ROOM_DIR}/STATE.md" reason="" registry newer text rc
  if [ ! -s "$state_file" ]; then
    reason="missing-or-empty"
  else
    registry="${MINDRIAN_ROOMS_HOME:-$HOME/MindrianRooms}/.rooms/registry.json"
    if [ -f "$registry" ] && [ "$registry" -nt "$state_file" ]; then
      reason="registry"
    elif [ -n "$(find "$state_file" -mmin +1440 -print -quit 2>/dev/null || true)" ]; then
      reason="age"
    else
      newer=$(room_newer "$state_file")
      if [ -n "$newer" ]; then
        reason="newer:${newer#"${ROOM_DIR}"/}"
      fi
    fi
  fi
  if [ -z "$reason" ]; then
    # DD-1 and DD-2: remove only the two keys that state-write.cjs added, and
    # accept only the exact compute-state shape. awk prints while it reads,
    # so the text is dropped when the exit code is not 0.
    text=$(awk '
NR == 1 { if ($0 != "---") { bad = 1; exit } ; fm = 1; print; next }
fm == 1 && $0 == "---" { fm = 2; print; next }
fm == 1 && /^computed:/ { seen = 1 }
fm == 1 && /^(gsd_state_version|status):/ { next }
fm == 2 { if ($0 != "# Data Room State") { bad = 1; exit } ; fm = 3; print; next }
fm == 3 && $0 == "## Live (auto)" { bad = 1; exit }
{ print }
END { if (bad || fm < 3 || !seen) exit 3 }
' "$state_file" 2>/dev/null)
    rc=$?
    if [ "$rc" -eq 0 ]; then
      printf '%s\n' "$text"
      log_line "state mode=reuse reason=unchanged"
      return 0
    fi
    reason="format"
  fi
  log_line "state mode=compute reason=${reason}"
  "${SCRIPT_DIR}/compute-state" "$ROOM_DIR" 2>/dev/null || echo "Could not compute room state. Your room exists but state analysis failed. Try /mos:status to diagnose."
}

do_analyze() {
  local cache="${ROOM_DIR}/.mindrian/analyze-room.cache" reason="" newer out rc tmp cached
  # DD-5: no .mindrian/ means no cache, no log, and no mkdir.
  if [ ! -d "${ROOM_DIR}/.mindrian" ]; then
    out=$("${SCRIPT_DIR}/analyze-room" "$ROOM_DIR" 2>/dev/null) || true
    printf '%s\n' "$out"
    return 0
  fi
  # DD-4: the cache is a miss on the first true check below.
  if [ ! -s "$cache" ]; then
    reason="missing-or-empty"
  elif [ "${SCRIPT_DIR}/analyze-room" -nt "$cache" ]; then
    reason="script"
  # Phase 381 PERF381-06: analyze logic lives in lib/core; room-render.cjs, room-render-analyze.cjs or room-scan.cjs newer than the cache is a miss.
  elif [ -f "${SCRIPT_DIR}/../lib/core/room-render.cjs" ] && [ "${SCRIPT_DIR}/../lib/core/room-render.cjs" -nt "$cache" ]; then
    reason="renderer"
  elif [ -f "${SCRIPT_DIR}/../lib/core/room-render-analyze.cjs" ] && [ "${SCRIPT_DIR}/../lib/core/room-render-analyze.cjs" -nt "$cache" ]; then
    reason="renderer"
  elif [ -f "${SCRIPT_DIR}/../lib/core/room-scan.cjs" ] && [ "${SCRIPT_DIR}/../lib/core/room-scan.cjs" -nt "$cache" ]; then
    reason="renderer"
  elif [ "${ROOM_DIR}/STATE.md" -nt "$cache" ]; then
    reason="state"
  elif [ -n "$(find "$cache" -mmin +1440 -print -quit 2>/dev/null || true)" ]; then
    reason="age"
  else
    newer=$(room_newer "$cache")
    if [ -n "$newer" ]; then
      reason="newer:${newer#"${ROOM_DIR}"/}"
    fi
  fi
  if [ -z "$reason" ]; then
    out=$(cat "$cache" 2>/dev/null)
    rc=$?
    if [ "$rc" -eq 0 ] && [ -n "$out" ]; then
      printf '%s\n' "$out"
      log_line "analyze mode=hit reason=unchanged rc=0 cached=yes"
      return 0
    fi
    reason="read-failed"
  fi
  # DD-6: print what analyze-room printed, whatever its exit code (as before
  # this change). Write the cache only for a clean run with real output.
  out=$("${SCRIPT_DIR}/analyze-room" "$ROOM_DIR" 2>/dev/null)
  rc=$?
  printf '%s\n' "$out"
  cached="no"
  if [ "$rc" -eq 0 ] && [ -n "$out" ] && [ "$out" != "NO_ROOM" ]; then
    tmp="${cache}.tmp.$$"
    if { printf '%s\n' "$out" > "$tmp"; } 2>/dev/null && mv -f "$tmp" "$cache" 2>/dev/null; then
      cached="yes"
    else
      rm -f "$tmp" 2>/dev/null || true
    fi
  fi
  log_line "analyze mode=miss reason=${reason} rc=${rc} cached=${cached}"
}

if [ "$MODE" = "state" ]; then
  do_state
else
  do_analyze
fi
exit 0