#!/usr/bin/env bash
# migrate-import.sh — restore a bundle made by migrate-export.sh onto THIS host.
#
# Run it from inside the target repo checkout (the compose project directory).
# It restores .env, certs/, and the docker volumes into THIS host's compose
# project, then prints the manual steps that finish the cutover.
#
# It assumes the machine already meets the requirements — run
#   tooling/migrate-check.sh
# first. It does NOT deploy the distribution repo, issue certs, or start the
# stack; those stay in your hands (see the printed tail + plan/22-migration.md).
#
# Usage:
#   tooling/migrate-import.sh BUNDLE.tar.gz
#   tooling/migrate-import.sh BUNDLE.tar.gz --path-prefix /home/ubuntu/mc=/home/you/mc
#   tooling/migrate-import.sh BUNDLE.tar.gz --without-certs
#   tooling/migrate-import.sh BUNDLE.tar.gz --force            # overwrite existing volumes
#
# --path-prefix OLD=NEW rewrites the source-absolute paths in .env
#   (DISTRIBUTION_WEB_ROOT, GENERATORS_REPO, GENERATORS_DATA_DIR, FILES_DATA_DIR)
#   to where they live on this host. Repeatable.
set -euo pipefail

cd "$(dirname "$0")/.."   # target repo root

log()  { printf '\n\033[1;32m==>\033[0m %s\n' "$*"; }
warn() { printf '\033[1;33m!!\033[0m %s\n' "$*" >&2; }
die()  { printf '\033[1;31mxx\033[0m %s\n' "$*" >&2; exit 1; }

# ── args ────────────────────────────────────────────────────────────
BUNDLE=""
WITH_CERTS=1
FORCE=0
declare -a PREFIXES=()
while [ $# -gt 0 ]; do
  case "$1" in
    --without-certs) WITH_CERTS=0; shift ;;
    --force)         FORCE=1; shift ;;
    --path-prefix)   PREFIXES+=("${2:?}"); shift 2 ;;
    -h|--help)       sed -n '2,26p' "$0"; exit 0 ;;
    -*)              die "unknown flag: $1 (see --help)" ;;
    *)               [ -z "$BUNDLE" ] || die "extra arg: $1"; BUNDLE="$1"; shift ;;
  esac
done
[ -n "$BUNDLE" ] || die "usage: $0 BUNDLE.tar.gz [--path-prefix OLD=NEW] [--without-certs] [--force]"
[ -f "$BUNDLE" ] || die "bundle not found: $BUNDLE"
BUNDLE="$(cd "$(dirname "$BUNDLE")" && pwd)/$(basename "$BUNDLE")"  # absolutize

command -v docker >/dev/null || die "docker required"
docker info >/dev/null 2>&1  || die "cannot reach the docker daemon"
docker compose version >/dev/null 2>&1 || die "docker compose v2 plugin required (see migrate-check.sh)"
[ -f docker-compose.yml ] || die "run this from inside the target repo checkout (no docker-compose.yml here)"

# ── target compose project name (default: this dir's basename) ──────
PROJ="${COMPOSE_PROJECT_NAME:-$(basename "$PWD")}"
log "target compose project: $PROJ  (in $PWD)"
warn "volumes will be restored as ${PROJ}_<name> — this MUST match what 'docker compose' uses here."
warn "if that looks wrong, set COMPOSE_PROJECT_NAME in .env and re-run."

# ── unpack the bundle to a temp staging dir ─────────────────────────
STAGE="$(mktemp -d "${TMPDIR:-/tmp}/ulicraft-import.XXXXXX")"
trap 'rm -rf "$STAGE"' EXIT
log "unpacking $(basename "$BUNDLE")"
tar -C "$STAGE" -xzf "$BUNDLE"
[ -f "$STAGE/MANIFEST.txt" ] || die "no MANIFEST.txt in bundle — is this a ulicraft migration bundle?"

log "manifest:"
sed 's/^/   /' "$STAGE/MANIFEST.txt"

# ── verify checksums ────────────────────────────────────────────────
log "verifying sha256 checksums"
( cd "$STAGE" && awk '/^[0-9a-f]{64} /{print}' MANIFEST.txt | sha256sum -c - ) \
  || die "checksum mismatch — bundle is corrupt or truncated"

# volumes present in the bundle
mapfile -t VOL_FILES < <(cd "$STAGE" && ls vol-*.tar.gz 2>/dev/null || true)
[ "${#VOL_FILES[@]}" -gt 0 ] || die "no volume archives in bundle"

# ── refuse to clobber existing volumes unless --force ───────────────
CLASH=0
for f in "${VOL_FILES[@]}"; do
  name="${f#vol-}"; name="${name%.tar.gz}"
  if docker volume inspect "${PROJ}_${name}" >/dev/null 2>&1; then
    warn "volume ${PROJ}_${name} already exists on this host"
    CLASH=1
  fi
done
if [ "$CLASH" -eq 1 ] && [ "$FORCE" -eq 0 ]; then
  die "existing volumes would be overwritten. Re-run with --force to replace them
     (their current contents are discarded). If this is the WRONG host, stop now."
fi

# ── restore .env (backup any existing one first) ────────────────────
if [ -f .env ]; then
  BK=".env.bak.pre-migrate.$(date +%Y%m%d-%H%M%S)"
  warn "existing .env → $BK"
  cp -a .env "$BK"
fi
log "restoring .env"
cp "$STAGE/.env" .env
chmod 600 .env

# apply --path-prefix rewrites
for p in "${PREFIXES[@]}"; do
  old="${p%%=*}"; new="${p#*=}"
  [ -n "$old" ] && [ "$old" != "$p" ] || die "bad --path-prefix '$p' (want OLD=NEW)"
  log "rewriting .env paths: $old -> $new"
  # only touch the RHS of KEY=... lines; escape / for sed
  esc_old="$(printf '%s' "$old" | sed 's/[.[\*^$/]/\\&/g')"
  esc_new="$(printf '%s' "$new" | sed 's/[&/]/\\&/g')"
  sed -i "s/${esc_old}/${esc_new}/g" .env
done

# ── sanity-check the host-path vars in .env resolve on THIS host ─────
log "checking host paths referenced by .env"
set -a; . ./.env; set +a
MISSING=0
for var in DISTRIBUTION_WEB_ROOT GENERATORS_REPO GENERATORS_DATA_DIR FILES_DATA_DIR; do
  val="${!var:-}"
  [ -n "$val" ] || { warn "$var unset in .env"; continue; }
  if [ -e "$val" ]; then
    printf '  \033[1;32m✓\033[0m %s = %s\n' "$var" "$val"
  else
    printf '  \033[1;33m!\033[0m %s = %s  (does NOT exist here)\n' "$var" "$val"
    MISSING=$((MISSING+1))
  fi
done
if [ "$MISSING" -gt 0 ]; then
  warn "$MISSING path(s) above don't exist on this host yet."
  warn "DISTRIBUTION_WEB_ROOT especially: the minecraft service bind-mounts kubejs"
  warn "from it and WON'T BOOT until it's populated. Deploy the distribution repo"
  warn "(and re-run with --path-prefix if the paths belong elsewhere) before starting."
fi

# ── restore certs/ ──────────────────────────────────────────────────
if [ "$WITH_CERTS" -eq 1 ] && [ -f "$STAGE/certs.tar.gz" ]; then
  log "restoring certs/"
  [ -d certs ] && warn "existing certs/ will be merged/overwritten from the bundle"
  tar -C . -xzf "$STAGE/certs.tar.gz"
elif [ "$WITH_CERTS" -eq 0 ]; then
  warn "--without-certs — not restoring certs; run tooling/issue-letsencrypt.sh here"
else
  warn "bundle has no certs.tar.gz — run tooling/issue-letsencrypt.sh here"
fi

# ── restore the docker volumes ──────────────────────────────────────
for f in "${VOL_FILES[@]}"; do
  name="${f#vol-}"; name="${name%.tar.gz}"
  vol="${PROJ}_${name}"
  log "restoring volume $vol"
  docker volume create "$vol" >/dev/null
  if [ "$FORCE" -eq 1 ]; then
    # wipe first so a --force restore is a clean replace, not a merge
    docker run --rm -v "$vol":/v alpine sh -c 'rm -rf /v/* /v/..?* /v/.[!.]* 2>/dev/null || true'
  fi
  docker run --rm -i -v "$vol":/v alpine tar -C /v -xzf - < "$STAGE/$f"
done

# ── done: print the manual tail ─────────────────────────────────────
cat <<EOF

$(printf '\033[1;32m==>\033[0m volumes + .env + certs restored.')

Remaining manual steps (see plan/22-migration.md for detail):

  1. Deploy the distribution repo so DISTRIBUTION_WEB_ROOT is populated
     (the minecraft service bind-mounts kubejs from it; it won't boot empty).
     Also add this host's Gitea deploy key for that repo.
  2. Fetch vendored bits:   tooling/fetch-authlib.sh   tooling/fetch-launcher.sh
     and (needs WAN)         tooling/sync-generators-data.sh
  3. Host nginx vhost:       tooling/render-nginx.sh --install
  4. Certificates:           tooling/issue-letsencrypt.sh
     (bundle certs boot nginx now, but nothing renews them until you run this)
  5. Open the firewall:      tcp 25565, 80, 443, ${CADDY_HTTP_PORT:-8880} ; udp 24454
  6. Point DNS ${BASE_DOMAIN:-\$BASE_DOMAIN} + subdomains at THIS host.
  7. Bring it up:            ./update-all.sh --hard
  8. Re-op players once they've joined:  docker compose exec minecraft rcon-cli op <name>

Fresh-world gotcha: if minecraft crash-loops on a fresh mc_data with
  "AccessDeniedException: /data/kubejs/config" (ConsoleJS.STARTUP null), Docker
  created /data/kubejs as root while the container runs as uid 1000. Fix once:
     docker compose stop minecraft
     docker run --rm -v ${PROJ}_mc_data:/data alpine chown 1000:1000 /data/kubejs
     docker compose up -d minecraft
  Details: plan/22-migration.md (Troubleshooting).

Rollback note: same domain means DNS points at ONE host. Once a player registers
or changes a skin here, this drasl.db diverges from cochi — rolling back to cochi
silently loses those changes. Keep the fallback window short.
EOF