#!/usr/bin/env bash
# muse-git-backup.sh — git-bridge backup mirror for muse/musehub -> GitHub
# See MuseHub staging issue #127 for full context.
#
# Usage:
#   ./muse-git-backup.sh preflight
#   ./muse-git-backup.sh replay-muse
#   ./muse-git-backup.sh replay-musehub
#   ./muse-git-backup.sh github-push
#   ./muse-git-backup.sh verify
#   ./muse-git-backup.sh incremental-muse
#   ./muse-git-backup.sh incremental-musehub
#
# Each subcommand is independent and safe to re-run. This script never
# touches ~/ecosystem/muse or ~/ecosystem/musehub — every operation targets
# the copies under /Users/gabriel/dev/copies 2/ and brand-new directories/
# GitHub repos this script creates fresh. Run as ./muse-git-backup.sh <cmd>,
# never sourced into your interactive shell — that's what makes `exit`
# inside this script safe (it only ends the script's own process).

set -euo pipefail

MUSE_COPY="/Users/gabriel/dev/copies 2/muse 03"
MUSEHUB_COPY="/Users/gabriel/dev/copies 2/musehub 03"
MUSE_GIT_BACKUP="/Users/gabriel/dev/copies 2/muse-git-backup"
MUSEHUB_GIT_BACKUP="/Users/gabriel/dev/copies 2/musehub-git-backup"
GH_MUSE_REPO="gabriel/muse-backup"
GH_MUSEHUB_REPO="gabriel/musehub-backup"

guard() {
  case "$1" in
    *ecosystem*) echo "❌ REFUSED: path contains 'ecosystem': $1"; exit 1 ;;
  esac
}

cmd_preflight() {
  test -d "$MUSE_COPY/.muse" && echo "muse copy: OK" || { echo "muse copy: MISSING .muse/ — STOP"; exit 1; }
  test -d "$MUSEHUB_COPY/.muse" && echo "musehub copy: OK" || { echo "musehub copy: MISSING .muse/ — STOP"; exit 1; }

  if [ -L "$MUSE_COPY" ]; then echo "STOP — muse copy is a symlink"; exit 1; fi
  if [ -L "$MUSEHUB_COPY" ]; then echo "STOP — musehub copy is a symlink"; exit 1; fi
  echo "muse copy: real directory, not a symlink"
  echo "musehub copy: real directory, not a symlink"

  echo "muse commit count:"
  muse -C "$MUSE_COPY" rev-list --count HEAD --json
  echo "musehub commit count:"
  muse -C "$MUSEHUB_COPY" rev-list --count HEAD --json
}

_replay_full_history() {
  local muse_copy="$1" git_backup="$2" label="$3"
  guard "$git_backup"

  mkdir -p "$git_backup"
  if [ ! -d "$git_backup/.git" ]; then
    git -C "$git_backup" init -q
    git -C "$git_backup" config user.email "gabriel@tellurstori.com"
    git -C "$git_backup" config user.name "gabriel"
    git -C "$git_backup" commit --allow-empty -qm "init ($label git-bridge backup mirror)"
  fi

  local commits total n
  commits=$(muse -C "$muse_copy" rev-list --reverse HEAD --json | python3 -c "import sys,json; print('\n'.join(json.load(sys.stdin)['commit_ids']))")
  if [ -n "${LIMIT:-}" ]; then
    commits=$(echo "$commits" | head -n "$LIMIT")
    echo "LIMIT=$LIMIT set — replaying only the first $LIMIT commits (dry run)"
    echo "⚠️  Before running the full replay, delete $git_backup — replay always"
    echo "    starts from commit 1, so re-running without cleanup duplicates these."
  fi
  total=$(echo "$commits" | wc -l | tr -d ' ')
  n=0
  while IFS= read -r cid; do
    n=$((n + 1))
    echo "[$n/$total] exporting $cid"
    (cd "$muse_copy" && muse bridge git-export \
      --muse-ref "$cid" \
      --git-dir "$git_backup" \
      --git-branch muse-mirror \
      --no-push \
      --allow-empty \
      --json)
  done <<< "$commits"

  echo "git history length:"
  git -C "$git_backup" rev-list --count muse-mirror
}

cmd_replay_muse() {
  _replay_full_history "$MUSE_COPY" "$MUSE_GIT_BACKUP" "muse"
}

cmd_replay_musehub() {
  _replay_full_history "$MUSEHUB_COPY" "$MUSEHUB_GIT_BACKUP" "musehub"
}

cmd_github_push() {
  gh auth status || { echo "Run 'gh auth login' first"; exit 1; }

  gh repo view "$GH_MUSE_REPO" >/dev/null 2>&1 || gh repo create "$GH_MUSE_REPO" --private --description "Git-bridge backup mirror of the muse Muse repo"
  gh repo view "$GH_MUSEHUB_REPO" >/dev/null 2>&1 || gh repo create "$GH_MUSEHUB_REPO" --private --description "Git-bridge backup mirror of the musehub Muse repo"

  git -C "$MUSE_GIT_BACKUP" remote get-url origin >/dev/null 2>&1 || git -C "$MUSE_GIT_BACKUP" remote add origin "git@github.com:$GH_MUSE_REPO.git"
  git -C "$MUSEHUB_GIT_BACKUP" remote get-url origin >/dev/null 2>&1 || git -C "$MUSEHUB_GIT_BACKUP" remote add origin "git@github.com:$GH_MUSEHUB_REPO.git"

  git -C "$MUSE_GIT_BACKUP" push -u origin muse-mirror
  git -C "$MUSEHUB_GIT_BACKUP" push -u origin muse-mirror
}

cmd_verify() {
  rm -rf /tmp/verify-muse-backup
  git clone "git@github.com:$GH_MUSE_REPO.git" /tmp/verify-muse-backup
  git -C /tmp/verify-muse-backup checkout muse-mirror
  echo "--- muse diff (expect no output) ---"
  diff -rq --exclude=.git --exclude=.muse "$MUSE_COPY" /tmp/verify-muse-backup || true

  rm -rf /tmp/verify-musehub-backup
  git clone "git@github.com:$GH_MUSEHUB_REPO.git" /tmp/verify-musehub-backup
  git -C /tmp/verify-musehub-backup checkout muse-mirror
  echo "--- musehub diff (expect no output) ---"
  diff -rq --exclude=.git --exclude=.muse "$MUSEHUB_COPY" /tmp/verify-musehub-backup || true
}

_incremental() {
  local muse_copy="$1" git_backup="$2"
  local last_bridged new_commits

  last_bridged=$(python3 -c "
import tomllib
with open('$muse_copy/.muse/git-bridge.toml', 'rb') as f:
    state = tomllib.load(f)
print(state['last_export']['muse_commit_id'])
")
  echo "Last bridged commit: $last_bridged"

  new_commits=$(muse -C "$muse_copy" rev-list "$last_bridged..HEAD" --reverse --json | python3 -c "import sys,json; print('\n'.join(json.load(sys.stdin)['commit_ids']))")

  if [ -z "$new_commits" ]; then
    echo "Nothing new since the last backup — done."
    return 0
  fi

  while IFS= read -r cid; do
    echo "exporting $cid"
    (cd "$muse_copy" && muse bridge git-export \
      --muse-ref "$cid" \
      --git-dir "$git_backup" \
      --git-branch muse-mirror \
      --no-push \
      --allow-empty \
      --json)
  done <<< "$new_commits"

  git -C "$git_backup" push origin muse-mirror
}

cmd_incremental_muse() {
  _incremental "$MUSE_COPY" "$MUSE_GIT_BACKUP"
}

cmd_incremental_musehub() {
  _incremental "$MUSEHUB_COPY" "$MUSEHUB_GIT_BACKUP"
}

SUBCOMMAND="${1:-}"
LIMIT=""
if [ "${2:-}" = "--limit" ]; then
  LIMIT="${3:?--limit requires a number}"
fi

case "$SUBCOMMAND" in
  preflight)           cmd_preflight ;;
  replay-muse)          cmd_replay_muse ;;
  replay-musehub)       cmd_replay_musehub ;;
  github-push)          cmd_github_push ;;
  verify)               cmd_verify ;;
  incremental-muse)     cmd_incremental_muse ;;
  incremental-musehub)  cmd_incremental_musehub ;;
  *)
    echo "Usage: $0 {preflight|replay-muse|replay-musehub|github-push|verify|incremental-muse|incremental-musehub} [--limit N]"
    exit 1
    ;;
esac