#!/usr/bin/env bash
# Sync persistent Copilot state files between machines using rsync over SSH.
# Only publish-log.tsv and project-ports-registry.json are synced; machine-
# local files (hook-events.log, session-events.tsv) and the quarantine
# directory are always excluded.
#
# Usage:
#   sync-copilot-state.sh --mode push|pull --remote user@host [options]
#
# Configuration:
#   Set COPILOT_STATE_SYNC_REMOTE in environment or in
#   ~/.copilot-resources-state/sync.conf to avoid passing --remote every time.

set -euo pipefail

state_dir="${COPILOT_RESOURCES_STATE_DIR:-$HOME/.copilot-resources-state}"
sync_conf="$state_dir/sync.conf"

dry_run="true"
mode=""
remote=""
ssh_port="22"

function usage() {
  cat >&2 <<EOF
Usage: sync-copilot-state.sh --mode <push|pull> [options]

Required:
  --mode <push|pull>       push: send local state to remote.
                           pull: fetch remote state to local.

Optional:
  --remote <user@host>     Remote SSH target. Overrides COPILOT_STATE_SYNC_REMOTE
                           and sync.conf.
  --remote-path <path>     Remote state directory. Default: ~/.copilot-resources-state
  --ssh-port <port>        SSH port. Default: 22
  --execute                Apply the sync. Default is dry-run.
  --help                   Show this help text.

Configuration file:
  $sync_conf
  Supported keys (shell variable syntax):
    COPILOT_STATE_SYNC_REMOTE=user@host
    COPILOT_STATE_SYNC_REMOTE_PATH=/custom/path
    COPILOT_STATE_SYNC_SSH_PORT=22
EOF
}

# Load optional config file before parsing args so args take precedence.
if [[ -f "$sync_conf" ]]; then
  # shellcheck source=/dev/null
  source "$sync_conf"
fi

remote="${COPILOT_STATE_SYNC_REMOTE:-}"
remote_path="${COPILOT_STATE_SYNC_REMOTE_PATH:-.copilot-resources-state}"
ssh_port="${COPILOT_STATE_SYNC_SSH_PORT:-22}"

while [[ $# -gt 0 ]]; do
  case "$1" in
    --mode)
      mode="$2"; shift 2 ;;
    --remote)
      remote="$2"; shift 2 ;;
    --remote-path)
      remote_path="$2"; shift 2 ;;
    --ssh-port)
      ssh_port="$2"; shift 2 ;;
    --execute)
      dry_run="false"; shift ;;
    --help)
      usage; exit 0 ;;
    *)
      printf 'Unknown argument: %s\n' "$1" >&2; usage; exit 1 ;;
  esac
done

if [[ -z "$mode" ]]; then
  printf '--mode push|pull is required.\n' >&2; usage; exit 1
fi

if [[ "$mode" != "push" && "$mode" != "pull" ]]; then
  printf '--mode must be push or pull.\n' >&2; exit 1
fi

if [[ -z "$remote" ]]; then
  printf 'No remote configured. Pass --remote user@host or set COPILOT_STATE_SYNC_REMOTE.\n' >&2
  exit 1
fi

mkdir -p -- "$state_dir"

# Files to sync: only durable shared state; exclude machine-local and ephemeral.
sync_files=(
  "publish-log.tsv"
  "project-ports-registry.json"
)

rsync_args=(-avz --checksum -e "ssh -p ${ssh_port}")

if [[ "$dry_run" == "true" ]]; then
  rsync_args+=(--dry-run)
  printf 'Dry-run mode — no changes will be made. Pass --execute to apply.\n\n'
fi

if [[ "$mode" == "push" ]]; then
  printf 'Pushing state to %s:%s\n\n' "$remote" "$remote_path"
  for file in "${sync_files[@]}"; do
    local_file="$state_dir/$file"
    if [[ ! -f "$local_file" ]]; then
      printf 'SKIP (not found): %s\n' "$local_file"
      continue
    fi
    printf 'SYNC: %s -> %s:%s/%s\n' "$local_file" "$remote" "$remote_path" "$file"
    rsync "${rsync_args[@]}" "$local_file" "${remote}:${remote_path}/${file}"
  done
else
  printf 'Pulling state from %s:%s\n\n' "$remote" "$remote_path"
  for file in "${sync_files[@]}"; do
    printf 'SYNC: %s:%s/%s -> %s/%s\n' "$remote" "$remote_path" "$file" "$state_dir" "$file"
    rsync "${rsync_args[@]}" "${remote}:${remote_path}/${file}" "$state_dir/${file}"
  done
fi

printf '\nDone.\n'