#!/usr/bin/env bash
#
# Central control script for remote Werkator operations (same pattern as the
# `remote` scripts in the other repos): the first argument is the repo selector,
# the second the command. All connection and deployment values come from the
# `.env` file in the repository root — never as command line parameters.
#
# NOTE: `install` (its clone step) and `build` are a prototype of the webspace
# self-build workflow. They proved the bwrap sandbox, but as a deployment path
# they invert ADR 0006 (build locally, install the bundle) and will be replaced
# by session D of docs/plan/21-werkdock-extraction-and-webspace-install.md.
#
# Usage:
#   tools/remote werkator check-prerequisites
#   tools/remote werkator install
#   tools/remote werkator build            # WERKATOR_BRANCH to override, default main
#   tools/remote werkator start
#   tools/remote port-forward start        # background tunnel to the Werkator UI
#   tools/remote port-forward stop
#   tools/remote werkator control-token
#
# Required in .env:
#   WERKATOR_REMOTE   user@host to operate on, e.g. mih34-werkator@mih34.hostsharing.net
#   WERKATOR_PATH     target directory on that host, e.g. /home/storage/mih34/users/werkator
#
# Required for `start`:
#   WERKATOR_PORT     the localhost port assigned by Hostsharing (eigener Serverdienst)
#   WERKATOR_DOMAIN   the domain served by the managed Apache, e.g. ci.example.de
#
# Required for `port-forward`:
#   WERKATOR_LOCAL_PORT   the local port the browser uses
# Optional in .env:
#   WERKATOR_BRANCH      branch for `build` (default: main)
#   WERKATOR_MEMORY_MAX  systemd MemoryMax for the unit, e.g. 1G (start)
#   WERKATOR_TASKS_MAX   systemd TasksMax for the unit, e.g. 512 (start)
#   WERKATOR_ROOTFS      rootfs archive path
#                       (default: <repo>/build/werkator-buildenv-trixie.tar.zst)
#
# Install layout on the host:
#   $WERKATOR_PATH/werkator/    the repository clone
#   $WERKATOR_PATH/.werkator/   runtime bundle + rootfs archive
#
# `install` performs, in order:
#   1. check-prerequisites  (bwrap capability + disk/quota, aborts on FAIL)
#   2. ensure SSH access    (ssh-copy-id on first use; asks for the password)
#   3. upload artifacts     (runtime bundle, built locally if missing, + rootfs)
#   4. clone the repository (needs the host SSH key registered at GitHub once —
#      the script prints the key and waits)
#   5. `werkator init` + machine-local bwrap configuration
#

set -euo pipefail

REPO="${1:-}"
COMMAND="${2:-}"

REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
PREREQ_SCRIPT="$REPO_ROOT/tools/werkator-build-prerequisites.sh"
RUNTIME_BUNDLE="$REPO_ROOT/build/distributions/werkator-runtime-linux-x64.tar.gz"
PID_FILE="/tmp/werkator-port-forward-$(id -u).pid"
LOG_FILE="/tmp/werkator-port-forward-$(id -u).log"

usage() {
    sed -n '3,38p' "${BASH_SOURCE[0]}" | sed 's/^# \{0,1\}//'
    exit 2
}

require_env() {
    local missing=0
    for name in "$@"; do
        if [ -z "${!name:-}" ]; then
            echo "ERROR: $name is not set — define it in $REPO_ROOT/.env" >&2
            missing=1
        fi
    done
    [ "$missing" -eq 0 ] || exit 1
}

[ -n "$REPO" ] && [ -n "$COMMAND" ] || usage

# Load the connection and deployment values; explicit environment wins, the
# .env in the repository root fills the rest.
set -a
[ -f "$REPO_ROOT/.env" ] && source "$REPO_ROOT/.env"
set +a

require_env WERKATOR_REMOTE WERKATOR_PATH
HOST="$WERKATOR_REMOTE"
TARGET_DIR="$WERKATOR_PATH"
ROOTFS="${WERKATOR_ROOTFS:-$REPO_ROOT/build/werkator-buildenv-trixie.tar.zst}"

ssh_present() {
    ssh -o BatchMode=yes -o ConnectTimeout=10 "$HOST" true 2>/dev/null
}

ensure_ssh() {
    if ssh_present; then
        echo "==> SSH access to $HOST: ok"
    else
        echo "==> No key-based SSH access yet; running ssh-copy-id (password prompt expected)"
        ssh-copy-id "$HOST"
        ssh_present || { echo "ERROR: SSH access still not working after ssh-copy-id" >&2; exit 1; }
    fi
}

# Run the prerequisites script remotely by piping it over stdin; TARGET_DIR and
# ROOTFS_ARCHIVE are passed as arguments to `bash -s --`.
check_prerequisites() {
    echo "==> Checking prerequisites on $HOST (target dir: $TARGET_DIR)"
    local rootfs_remote="$TARGET_DIR/.werkator/$(basename "$ROOTFS")"
    if ! ssh "$HOST" "WERKATOR_SSH_TARGET='$HOST' bash -s -- '$TARGET_DIR' '$rootfs_remote'" < "$PREREQ_SCRIPT"; then
        echo "ERROR: prerequisites failed on $HOST — install aborted" >&2
        exit 1
    fi
}

ensure_local_artifacts() {
    if [ ! -f "$RUNTIME_BUNDLE" ]; then
        echo "==> Runtime bundle not found; building it locally (./gradlew runtimeBundle)"
        (cd "$REPO_ROOT" && ./gradlew runtimeBundle --console=plain -q)
    fi
    [ -f "$RUNTIME_BUNDLE" ] || { echo "ERROR: runtime bundle missing: $RUNTIME_BUNDLE" >&2; exit 1; }
    [ -f "$ROOTFS" ] || {
        echo "ERROR: rootfs archive missing: $ROOTFS" >&2
        echo "       build it with tools/build-bwrap-rootfs.sh or set WERKATOR_ROOTFS" >&2
        exit 1
    }
}

ensure_github_access() {
    # `ssh -T git@github.com` exits 1 even on success ("does not provide shell
    # access") — neutralize remotely, then match on the greeting text.
    if ssh "$HOST" 'ssh -o BatchMode=yes -o ConnectTimeout=10 -T git@github.com 2>&1 || true' | grep -q "successfully authenticated"; then
        echo "==> GitHub SSH access from $HOST: ok"
        return 0
    fi
    echo
    echo "==> The host cannot reach GitHub via SSH yet."
    echo "    Add THIS public key to GitHub (Settings > SSH and GPG keys > New SSH key):"
    ssh "$HOST" 'cat ~/.ssh/id_*.pub 2>/dev/null' || {
        echo "ERROR: no public key on the host; create one with ssh-keygen -t ed25519" >&2
        exit 1
    }
    read -r -p "    Press Enter once the key is registered at GitHub... "
    ssh "$HOST" 'ssh -o BatchMode=yes -T git@github.com 2>&1 || true' | grep -q "successfully authenticated" || {
        echo "ERROR: GitHub authentication from $HOST still failing" >&2
        exit 1
    }
    echo "==> GitHub SSH access from $HOST: ok"
}

install() {
    ensure_ssh
    check_prerequisites
    ensure_local_artifacts

    echo "==> Uploading runtime bundle and rootfs archive"
    ssh "$HOST" "mkdir -p '$TARGET_DIR/.werkator'"
    scp -q "$RUNTIME_BUNDLE" "$HOST:$TARGET_DIR/.werkator/"
    scp -q "$ROOTFS" "$HOST:$TARGET_DIR/.werkator/"

    echo "==> Unpacking runtime bundle"
    ssh "$HOST" "tar xzf '$TARGET_DIR/.werkator/$(basename "$RUNTIME_BUNDLE")' -C '$TARGET_DIR/.werkator'"
    ssh "$HOST" "'$TARGET_DIR/.werkator/werkator/bin/werkator' --version"

    ensure_github_access

    echo "==> Cloning the repository"
    if ssh "$HOST" "test -d '$TARGET_DIR/werkator/.git'"; then
        echo "    (already cloned, skipping)"
    else
        ssh "$HOST" "git clone git@github.com:mhoennig/werkator.git '$TARGET_DIR/werkator'"
    fi

    echo "==> Running werkator init"
    ssh "$HOST" "cd '$TARGET_DIR/werkator' && '$TARGET_DIR/.werkator/werkator/bin/werkator' init"

    echo "==> Writing machine-local bwrap configuration"
    ssh "$HOST" "grep -q '^  bwrap:' '$TARGET_DIR/werkator/.git/werkator/.werkator.yml' 2>/dev/null" || ssh "$HOST" "cat >> '$TARGET_DIR/werkator/.git/werkator/.werkator.yml' <<'CFG'

# Build in the bubblewrap sandbox instead of natively (Step 17 / ADR 0007).
# Both keys are pinned: read from this machine config even if a branch sets
# its own values in a committed .werkator.yml.
builds:
  default:
    bwrap:
      enabled: true
      rootfs: $TARGET_DIR/.werkator/$(basename "$ROOTFS")
CFG"

    echo "==> Verifying the effective configuration"
    ssh "$HOST" "cd '$TARGET_DIR/werkator' && '$TARGET_DIR/.werkator/werkator/bin/werkator' config:print 2>/dev/null | grep -A3 'bwrap:' | head -4"

    echo
    echo "==> Install complete."
    echo "    Repo:     $TARGET_DIR/werkator"
    echo "    Runtime:  $TARGET_DIR/.werkator/werkator/bin/werkator"
    echo "    Next:     tools/remote werkator build"
}

build() {
    ensure_ssh
    local branch="${WERKATOR_BRANCH:-main}"
    echo "==> Running one initial build of branch '$branch' on $HOST (in the bwrap sandbox)"
    ssh -t "$HOST" "cd '$TARGET_DIR/werkator' && '$TARGET_DIR/.werkator/werkator/bin/werkator' build '$branch'"
}

# Start the server as a systemd user unit behind the managed Apache.
# WERKATOR_MEMORY_MAX / WERKATOR_TASKS_MAX (optional) are written into the
# machine config so `init --systemd` bakes them into the unit.
start() {
    ensure_ssh
    require_env WERKATOR_PORT WERKATOR_DOMAIN
    local machine="$TARGET_DIR/werkator/.git/werkator/.werkator.yml"
    local unit="werkator-$(basename "$TARGET_DIR/werkator").service"
    local htaccess="$TARGET_DIR/doms/$WERKATOR_DOMAIN/subs/www/.htaccess"

    echo "==> Writing server settings to the machine config"
    if ssh "$HOST" "grep -q '^server:' '$machine' 2>/dev/null"; then
        # re-run: update port and publicBaseUrl in place (systemd limits stay as written)
        ssh "$HOST" "sed -i 's/^  port: .*/  port: $WERKATOR_PORT/; s|^  publicBaseUrl: .*|  publicBaseUrl: \"https://$WERKATOR_DOMAIN/\"|' '$machine'"
    else
        ssh "$HOST" "cat >> '$machine' <<'CFG'

# Web access: the managed Apache terminates TLS and proxies to the localhost
# port assigned by Hostsharing (eigener Serverdienst); TLS is the domain's
# Let's Encrypt certificate, so Werkator itself stays on 127.0.0.1.
server:
  port: $WERKATOR_PORT
  bindAddress: 127.0.0.1
  publicBaseUrl: \"https://$WERKATOR_DOMAIN/\"
  nginx:
    enabled: false
  systemd:
    memoryMax: \"${WERKATOR_MEMORY_MAX:-}\"
    tasksMax: \"${WERKATOR_TASKS_MAX:-}\"
CFG"
    fi

    echo "==> Writing the Apache reverse proxy to $htaccess"
    ssh "$HOST" "mkdir -p '$TARGET_DIR/doms/$WERKATOR_DOMAIN/subs/www' && cat > '$htaccess' <<'HT'
DirectoryIndex disabled
RewriteEngine On
RewriteBase /
RewriteRule .* http://127.0.0.1:$WERKATOR_PORT%{REQUEST_URI} [proxy]
HT"

    echo "==> Generating the systemd user unit (init --systemd)"
    ssh "$HOST" "cd '$TARGET_DIR/werkator' && '$TARGET_DIR/.werkator/werkator/bin/werkator' init --systemd"

    echo "==> Linking the units into ~/.config/systemd/user and enabling the service"
    ssh "$HOST" "mkdir -p ~/.config/systemd/user && \
      ln -sf '$TARGET_DIR/werkator/.git/werkator/$unit' ~/.config/systemd/user/ && \
      ln -sf '$TARGET_DIR/werkator/.git/werkator/werkator-docker-prune.service' ~/.config/systemd/user/ && \
      ln -sf '$TARGET_DIR/werkator/.git/werkator/werkator-docker-prune.timer' ~/.config/systemd/user/ && \
      systemctl --user daemon-reload && systemctl --user restart '$unit' && systemctl --user status '$unit' --no-pager -l | head -12"

    echo
    echo "==> Server started. Verify: https://$WERKATOR_DOMAIN/"
    echo "    Logs: ssh $HOST -- systemctl --user status '$unit'"
}

# Background SSH tunnel to the Werkator server, so the browser reaches the UI
# at http://localhost:<WERKATOR_LOCAL_PORT> without keeping a terminal busy.
# `start` runs ssh -N -L detached with a pid file; `stop` kills it.
port_forward() {
    require_env WERKATOR_LOCAL_PORT
    local remote_port
    remote_port="$(ssh "$HOST" "awk '/^server:/{f=1;next} f && /^  port:/{print \$2; exit}' '$TARGET_DIR/werkator/.git/werkator/.werkator.yml'")"
    [ -n "$remote_port" ] || { echo "ERROR: no server.port in the machine config — run 'tools/remote werkator start' first" >&2; exit 1; }

    case "$COMMAND" in
        start)
            if [ -f "$PID_FILE" ] && kill -0 "$(cat "$PID_FILE")" 2>/dev/null; then
                echo "==> Port-forward already running (pid $(cat "$PID_FILE")) — http://localhost:$WERKATOR_LOCAL_PORT"
                exit 0
            fi
            nohup ssh -N -L "$WERKATOR_LOCAL_PORT:127.0.0.1:$remote_port" "$HOST" \
                >"$LOG_FILE" 2>&1 &
            echo $! > "$PID_FILE"
            sleep 1
            if kill -0 "$(cat "$PID_FILE")" 2>/dev/null; then
                echo "==> Forwarding http://localhost:$WERKATOR_LOCAL_PORT -> $HOST:127.0.0.1:$remote_port (pid $(cat "$PID_FILE"))"
            else
                echo "ERROR: port-forward failed to start — see $LOG_FILE" >&2
                rm -f "$PID_FILE"
                exit 1
            fi
            ;;
        stop)
            if [ -f "$PID_FILE" ] && kill -0 "$(cat "$PID_FILE")" 2>/dev/null; then
                kill "$(cat "$PID_FILE")"
                rm -f "$PID_FILE"
                echo "==> Port-forward stopped"
            else
                rm -f "$PID_FILE"
                echo "==> Port-forward is not running"
            fi
            ;;
        *)
            echo "ERROR: unknown port-forward command: $COMMAND (use start or stop)" >&2
            exit 2
            ;;
    esac
}

# Print the control token guarding the mutating build endpoints. If the server
# has not created it yet (it does so on first use), generate one in place — the
# server reads the file lazily, so a pre-created token is equivalent.
control_token() {
    ensure_ssh
    local token_file="$TARGET_DIR/werkator/.git/werkator/control-token"
    ssh "$HOST" "if [ -f '$token_file' ]; then cat '$token_file'; else \
        umask 077 && head -c 32 /dev/urandom | od -An -tx1 | tr -d ' \\n' > '$token_file' && cat '$token_file'; fi"
}

case "$REPO" in
    port-forward)
        port_forward
        ;;
    werkator)
        case "$COMMAND" in
            check-prerequisites)
                ensure_ssh
                check_prerequisites
                ;;
            install)
                install
                ;;
            build)
                build
                ;;
            start)
                start
                ;;
            control-token)
                control_token
                ;;
            *)
                echo "ERROR: unknown command: $COMMAND" >&2
                usage
                ;;
        esac
        ;;
    *)
        echo "ERROR: unknown repo selector: $REPO" >&2
        usage
        ;;
esac