#!/usr/bin/env bash
# on-cwd-changed: CwdChanged hook handler for MindrianOS
# Auto-switches the active room when the user changes directory to a
# registered room path. Updates the registry and injects new room context.
# Must complete in under 2 seconds.

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PLUGIN_ROOT="$(cd "${SCRIPT_DIR}/.." && pwd)"

# ---------------------------------------------------------------------------
# Phase 95-04: CwdChanged envelope helper.
#
# Allowed top-level keys per Claude Code 2.x CwdChanged schema:
#   continue, stopReason, suppressOutput, systemMessage
# CwdChanged does NOT accept hookSpecificOutput. Pre-fix the success path
# emitted `{hookSpecificOutput: {hookEventName: "SessionStart", ...}}`
# which violates the per-event allowed key set.
# ---------------------------------------------------------------------------
emit_cwd_changed_envelope() {
  local msg="$1"
  if [ -z "$msg" ]; then return 0; fi
  jq -nc --arg m "$msg" '{
    systemMessage: $m,
    suppressOutput: false
  }'
}

# New working directory (passed by hook or use PWD)
NEW_DIR="${1:-$PWD}"

# Try to resolve a room at the new directory
NEW_ROOM=$("${SCRIPT_DIR}/resolve-room" "$NEW_DIR" 2>/dev/null) || NEW_ROOM=""

# Also check if new dir IS inside a room (walk up to find STATE.md)
if [ -z "$NEW_ROOM" ]; then
  check_dir="$NEW_DIR"
  while [ "$check_dir" != "/" ] && [ "$check_dir" != "." ]; do
    if [ -f "$check_dir/STATE.md" ]; then
      # Found a room -- try to resolve from parent
      parent_dir=$(dirname "$check_dir")
      NEW_ROOM=$("${SCRIPT_DIR}/resolve-room" "$parent_dir" 2>/dev/null) || NEW_ROOM=""
      if [ -z "$NEW_ROOM" ]; then
        # Legacy room without registry -- adopt it
        NEW_ROOM=$("${SCRIPT_DIR}/resolve-room" "$parent_dir" --adopt 2>/dev/null) || NEW_ROOM=""
      fi
      break
    fi
    check_dir=$(dirname "$check_dir")
  done
fi

if [ -z "$NEW_ROOM" ]; then
  # 95-04: silent on diagnostic paths. CwdChanged does not accept
  # status at root. No message needed for the no-room case.
  # silent: no room at new directory
  exit 0
fi

# Check if this is different from the currently active room
OLD_ROOM=$("${SCRIPT_DIR}/resolve-room" "$PWD" 2>/dev/null) || OLD_ROOM=""

if [ "$NEW_ROOM" = "$OLD_ROOM" ]; then
  # silent: same room - no switch needed
  exit 0
fi

# Update registry to point to the new room
# Find the registry that contains this room
REGISTRY_FILE=""
for reg_candidate in "${NEW_DIR}/.rooms/registry.json" "$(dirname "$NEW_ROOM")/.rooms/registry.json"; do
  if [ -f "$reg_candidate" ]; then
    REGISTRY_FILE="$reg_candidate"
    break
  fi
done

if [ -n "$REGISTRY_FILE" ]; then
  python3 -c "
import json, os, sys
# RCA windows-python-interp-and-shim: paths arrive via sys.argv, never
# interpolated into this source text (a Windows backslash path would otherwise
# be re-parsed as a Python escape sequence and SyntaxError before this runs).
reg_path = sys.argv[1]
new_room = sys.argv[2]

with open(reg_path) as f:
    reg = json.load(f)

# Find which room entry matches the new room path
for name, room in reg.get('rooms', {}).items():
    abs_path = os.path.normpath(os.path.join(os.path.dirname(reg_path).replace('/.rooms', ''), room['path']))
    if abs_path == new_room:
        reg['active'] = name
        import datetime
        room['last_opened'] = datetime.datetime.now(datetime.UTC).strftime('%Y-%m-%dT%H:%M:%SZ')
        break

tmp = reg_path + '.tmp'
with open(tmp, 'w') as f:
    json.dump(reg, f, indent=2)
os.replace(tmp, reg_path)
" "$REGISTRY_FILE" "$NEW_ROOM" 2>/dev/null || true
fi

# Compute state for the new room
state_output=$("${SCRIPT_DIR}/compute-state" "$NEW_ROOM" 2>/dev/null || echo "Error computing state")

# Read plugin version via platform.cjs (plan 85-06 sweep).
PLUGIN_VERSION=$(node -e "try{process.stdout.write(require('$PLUGIN_ROOT/lib/core/platform.cjs').readPluginJsonVersion('$PLUGIN_ROOT'))}catch(e){process.stdout.write('unknown')}" 2>/dev/null || echo "unknown")

# Build context for the new room
room_name=$(basename "$NEW_ROOM")
context="[MindrianOS Room Switch] Switched to room: ${room_name}\n\n${state_output}\n\nYou are Larry. MindrianOS v${PLUGIN_VERSION}. The user switched to a different Data Room. Greet them with awareness of this room's state."

# Escape for JSON
escape_for_json() {
  local s="$1"
  s="${s//\\/\\\\}"
  s="${s//\"/\\\"}"
  s="${s//$'\n'/\\n}"
  s="${s//$'\r'/\\r}"
  s="${s//$'\t'/\\t}"
  printf '%s' "$s"
}

escaped_context=$(escape_for_json "$context")

# Track room switch in analytics
bash "${SCRIPT_DIR}/track-analytics" room-switch 2>/dev/null &

# Phase 95-04: CwdChanged does NOT accept hookSpecificOutput per the
# Claude Code 2.x schema. Stdout carries only systemMessage. The full
# room state is no longer surfaced through stdout, but the next
# SessionStart fires anyway and re-injects active-room context.
#
# Phase 95-01 audit: this Cursor branch (CURSOR_PLUGIN_ROOT-gated) is
# invalid for Claude Code 2.x but valid for Cursor's hook system. The
# divergence is intentional. See .planning/phases/95-bash-hook-envelope-and-cascade-side-channel/95-01-AUDIT.md row #9.
if [ -n "${CURSOR_PLUGIN_ROOT:-}" ]; then
  # Cursor branch: kept for compatibility. See 95-01-AUDIT.md row #9.
  printf '{\n  "additional_context": "%s"\n}\n' "$escaped_context"
else
  # Claude path: schema-compliant CwdChanged envelope (systemMessage only).
  emit_cwd_changed_envelope "Switched to room: ${room_name}"
fi

exit 0