#!/usr/bin/env bash
set -euo pipefail

# =============================================================================
# manage_runner.sh — Add, remove, or list Gitea Actions runners
# Reads runner definitions from runners.conf (pipe-delimited format).
# Supports two runner types:
#   docker — Linux hosts, deployed as Docker container via docker-compose
#   native — macOS, deployed as binary + launchd service
# Can be used standalone or called by phase3_runners.sh / phase3_teardown.sh.
# =============================================================================

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
source "${SCRIPT_DIR}/lib/common.sh"

load_env
require_vars GITEA_INTERNAL_URL GITEA_ADMIN_TOKEN ACT_RUNNER_VERSION

RUNNERS_CONF="${SCRIPT_DIR}/runners.conf"

# ---------------------------------------------------------------------------
# Usage
# ---------------------------------------------------------------------------
usage() {
  cat >&2 <<EOF
Usage: $(basename "$0") <command> [options]

Commands:
  add    --name <runner_name>    Deploy and register a runner
  remove --name <runner_name>    Stop and deregister a runner
  list                           Show all runners with status

Options:
  --name <name>    Runner name as defined in runners.conf
  --help           Show this help
EOF
  exit 1
}

# ---------------------------------------------------------------------------
# Parse a runner entry from runners.conf by name
# Sets: RUNNER_NAME, RUNNER_SSH_HOST, RUNNER_SSH_USER, RUNNER_SSH_PORT,
#        RUNNER_DATA_PATH, RUNNER_LABELS, RUNNER_TYPE
# Returns 1 if not found.
# ---------------------------------------------------------------------------
parse_runner_entry() {
  local target_name="$1"

  if [[ ! -f "$RUNNERS_CONF" ]]; then
    log_error "runners.conf not found at $RUNNERS_CONF"
    return 1
  fi

  while IFS='|' read -r name host user port path labels type; do
    # Skip comments and blank lines
    [[ "$name" =~ ^[[:space:]]*# ]] && continue
    [[ -z "$name" ]] && continue

    # Trim whitespace from fields
    name=$(echo "$name" | xargs)

    if [[ "$name" == "$target_name" ]]; then
      RUNNER_NAME="$name"
      RUNNER_SSH_HOST=$(echo "$host" | xargs)
      RUNNER_SSH_USER=$(echo "$user" | xargs)
      RUNNER_SSH_PORT=$(echo "$port" | xargs)
      RUNNER_DATA_PATH=$(echo "$path" | xargs)
      RUNNER_LABELS=$(echo "$labels" | xargs)
      RUNNER_TYPE=$(echo "$type" | xargs)
      return 0
    fi
  done < "$RUNNERS_CONF"

  log_error "Runner '$target_name' not found in runners.conf"
  return 1
}

# ---------------------------------------------------------------------------
# List all runner entries from runners.conf (without looking up a name)
# Outputs lines to stdout: name|host|user|port|path|labels|type
# ---------------------------------------------------------------------------
all_runner_entries() {
  if [[ ! -f "$RUNNERS_CONF" ]]; then
    log_error "runners.conf not found at $RUNNERS_CONF"
    return 1
  fi

  while IFS= read -r line; do
    # Skip comments and blank lines
    [[ "$line" =~ ^[[:space:]]*# ]] && continue
    [[ -z "$line" ]] && continue
    echo "$line"
  done < "$RUNNERS_CONF"
}

# ---------------------------------------------------------------------------
# Execute a command on the runner's host.
# For "local" hosts (macOS), runs the command directly.
# For remote hosts, SSHs into them — uses direct ssh (not ssh_exec from
# common.sh) because runner hosts have their own SSH creds defined in
# runners.conf, not from the standard *_IP/*_SSH_USER env vars.
# ---------------------------------------------------------------------------
runner_ssh() {
  local cmd="$*"

  if [[ "$RUNNER_SSH_HOST" == "local" ]]; then
    # macOS runner — execute directly on this machine
    eval "$cmd"
  else
    ssh -o ConnectTimeout=10 \
        -o StrictHostKeyChecking=accept-new \
        -o BatchMode=yes \
        -p "${RUNNER_SSH_PORT}" \
        "${RUNNER_SSH_USER}@${RUNNER_SSH_HOST}" \
        "$cmd"
  fi
}

# ---------------------------------------------------------------------------
# SCP a file to the runner's host.
# For "local" hosts, just copies the file.
# ---------------------------------------------------------------------------
runner_scp() {
  local src="$1" dst="$2"

  if [[ "$RUNNER_SSH_HOST" == "local" ]]; then
    cp "$src" "$dst"
  else
    scp -o ConnectTimeout=10 \
        -o StrictHostKeyChecking=accept-new \
        -o BatchMode=yes \
        -P "${RUNNER_SSH_PORT}" \
        "$src" "${RUNNER_SSH_USER}@${RUNNER_SSH_HOST}:${dst}"
  fi
}

# ---------------------------------------------------------------------------
# add_docker_runner — Deploy a runner as a Docker container on a Linux host
# Steps:
#   1. Create data directory
#   2. Render + SCP docker-compose.yml
#   3. Render + SCP runner-config.yaml
#   4. Start container
# The act_runner Docker image auto-registers with Gitea using env vars
# (GITEA_INSTANCE_URL + GITEA_RUNNER_REGISTRATION_TOKEN) on first boot.
# ---------------------------------------------------------------------------
add_docker_runner() {
  log_info "Deploying Docker runner '${RUNNER_NAME}' on ${RUNNER_SSH_HOST}..."

  # Check if container is already running
  local status
  status=$(runner_ssh "docker ps --filter name=gitea-runner-${RUNNER_NAME} --format '{{.Status}}'" 2>/dev/null || true)
  if [[ "$status" == *"Up"* ]]; then
    log_info "Runner '${RUNNER_NAME}' already running — skipping"
    return 0
  fi

  # Create data directory on remote host
  runner_ssh "mkdir -p '${RUNNER_DATA_PATH}'"

  # Render docker-compose template with runner-specific vars
  local tmpfile
  tmpfile=$(mktemp)
  export RUNNER_NAME RUNNER_LABELS RUNNER_DATA_PATH
  export GITEA_RUNNER_REGISTRATION_TOKEN="${GITEA_RUNNER_REGISTRATION_TOKEN:-}"
  render_template "${SCRIPT_DIR}/templates/docker-compose-runner.yml.tpl" "$tmpfile" \
    "\${ACT_RUNNER_VERSION} \${RUNNER_NAME} \${GITEA_INTERNAL_URL} \${GITEA_RUNNER_REGISTRATION_TOKEN} \${RUNNER_LABELS} \${RUNNER_DATA_PATH}"
  runner_scp "$tmpfile" "${RUNNER_DATA_PATH}/docker-compose.yml"
  rm -f "$tmpfile"

  # Render runner config
  tmpfile=$(mktemp)
  render_template "${SCRIPT_DIR}/templates/runner-config.yaml.tpl" "$tmpfile" \
    "\${RUNNER_NAME} \${RUNNER_LABELS}"
  runner_scp "$tmpfile" "${RUNNER_DATA_PATH}/config.yaml"
  rm -f "$tmpfile"

  # Start the container
  runner_ssh "cd '${RUNNER_DATA_PATH}' && docker compose up -d 2>/dev/null || docker-compose up -d"
  log_success "Docker runner '${RUNNER_NAME}' started on ${RUNNER_SSH_HOST}"
}

# ---------------------------------------------------------------------------
# add_native_runner — Deploy a runner as a native binary on macOS
# Steps:
#   1. Download act_runner binary for macOS (arm64 or amd64)
#   2. Register with Gitea (--no-interactive)
#   3. Render launchd plist
#   4. Load plist via launchctl
# Native runners are used on macOS because Docker Desktop is heavyweight
# and unreliable for long-running background services.
# ---------------------------------------------------------------------------
add_native_runner() {
  # Native runners use launchctl + macOS-specific paths — must be macOS
  require_local_os "Darwin" "Native runner deployment requires macOS (uses launchctl)"

  log_info "Deploying native runner '${RUNNER_NAME}' on local machine..."

  # Resolve ~ to actual home directory for local execution
  RUNNER_DATA_PATH="${RUNNER_DATA_PATH/#\~/$HOME}"
  export RUNNER_DATA_PATH

  local plist_name="com.gitea.runner.${RUNNER_NAME}.plist"
  local plist_path="$HOME/Library/LaunchAgents/${plist_name}"

  # Check if launchd service is already loaded
  if launchctl list 2>/dev/null | grep -q "com.gitea.runner.${RUNNER_NAME}"; then
    log_info "Runner '${RUNNER_NAME}' already loaded in launchd — skipping"
    return 0
  fi

  # Create data directory
  mkdir -p "${RUNNER_DATA_PATH}"

  # Download act_runner binary if not present
  if [[ ! -x "${RUNNER_DATA_PATH}/act_runner" ]]; then
    # Detect architecture — Apple Silicon (arm64) vs Intel (x86_64)
    local arch
    arch=$(uname -m)
    case "$arch" in
      arm64)  arch="arm64" ;;
      x86_64) arch="amd64" ;;
      *)      log_error "Unsupported architecture: $arch"; return 1 ;;
    esac

    local download_url="https://gitea.com/gitea/act_runner/releases/download/v${ACT_RUNNER_VERSION}/act_runner-${ACT_RUNNER_VERSION}-darwin-${arch}"
    log_info "Downloading act_runner v${ACT_RUNNER_VERSION} for darwin-${arch}..."
    curl -sfL -o "${RUNNER_DATA_PATH}/act_runner" "$download_url"
    chmod +x "${RUNNER_DATA_PATH}/act_runner"
    log_success "act_runner binary downloaded"
  fi

  # Register the runner with Gitea (generates .runner file in data dir)
  # --no-interactive skips prompts, --config generates default config if missing
  if [[ ! -f "${RUNNER_DATA_PATH}/.runner" ]]; then
    log_info "Registering runner with Gitea..."
    "${RUNNER_DATA_PATH}/act_runner" register \
      --no-interactive \
      --instance "${GITEA_INTERNAL_URL}" \
      --token "${GITEA_RUNNER_REGISTRATION_TOKEN:-}" \
      --name "${RUNNER_NAME}" \
      --labels "${RUNNER_LABELS}" \
      --config "${RUNNER_DATA_PATH}/config.yaml"
    log_success "Runner registered"
  fi

  # Render runner config (overwrites any default generated by register)
  local tmpfile
  tmpfile=$(mktemp)
  export RUNNER_NAME RUNNER_LABELS RUNNER_DATA_PATH
  render_template "${SCRIPT_DIR}/templates/runner-config.yaml.tpl" "$tmpfile" \
    "\${RUNNER_NAME} \${RUNNER_LABELS}"
  cp "$tmpfile" "${RUNNER_DATA_PATH}/config.yaml"
  rm -f "$tmpfile"

  # Render launchd plist
  tmpfile=$(mktemp)
  render_template "${SCRIPT_DIR}/templates/com.gitea.runner.plist.tpl" "$tmpfile" \
    "\${RUNNER_NAME} \${RUNNER_DATA_PATH}"
  mkdir -p "$HOME/Library/LaunchAgents"
  cp "$tmpfile" "$plist_path"
  rm -f "$tmpfile"

  # Load the launchd service
  launchctl load "$plist_path"
  log_success "Native runner '${RUNNER_NAME}' loaded via launchd"
}

# ---------------------------------------------------------------------------
# remove_docker_runner — Stop + remove Docker runner container
# ---------------------------------------------------------------------------
remove_docker_runner() {
  log_info "Removing Docker runner '${RUNNER_NAME}' from ${RUNNER_SSH_HOST}..."

  # Check if docker-compose file exists
  if runner_ssh "test -f '${RUNNER_DATA_PATH}/docker-compose.yml'" 2>/dev/null; then
    runner_ssh "cd '${RUNNER_DATA_PATH}' && docker compose down 2>/dev/null || docker-compose down" || true
    log_success "Docker runner '${RUNNER_NAME}' stopped"
  else
    log_info "No docker-compose.yml found for runner '${RUNNER_NAME}' — already removed"
  fi
}

# ---------------------------------------------------------------------------
# remove_native_runner — Unload launchd service + remove binary + plist
# ---------------------------------------------------------------------------
remove_native_runner() {
  # Native runners use launchctl + macOS-specific paths — must be macOS
  require_local_os "Darwin" "Native runner removal requires macOS (uses launchctl)"

  log_info "Removing native runner '${RUNNER_NAME}' from local machine..."

  # Resolve ~ to actual home directory
  RUNNER_DATA_PATH="${RUNNER_DATA_PATH/#\~/$HOME}"

  local plist_name="com.gitea.runner.${RUNNER_NAME}.plist"
  local plist_path="$HOME/Library/LaunchAgents/${plist_name}"

  # Unload launchd service if loaded
  if launchctl list 2>/dev/null | grep -q "com.gitea.runner.${RUNNER_NAME}"; then
    launchctl unload "$plist_path" 2>/dev/null || true
    log_success "Launchd service unloaded"
  fi

  # Remove plist file
  if [[ -f "$plist_path" ]]; then
    rm -f "$plist_path"
    log_success "Plist removed: $plist_path"
  fi

  # Remove runner data directory (binary, config, registration)
  if [[ -d "${RUNNER_DATA_PATH}" ]]; then
    printf 'Remove runner data at %s? [y/N] ' "${RUNNER_DATA_PATH}"
    read -r confirm
    if [[ "$confirm" =~ ^[Yy]$ ]]; then
      rm -rf "${RUNNER_DATA_PATH}"
      log_success "Runner data removed"
    else
      log_info "Runner data preserved"
    fi
  fi
}

# ---------------------------------------------------------------------------
# list_runners — Print table of all runners with their Gitea status
# Queries the Gitea admin API for registered runners and cross-references
# with runners.conf to show which are online/offline/unregistered.
# ---------------------------------------------------------------------------
list_runners() {
  log_info "Listing runners..."

  # Fetch registered runners from Gitea admin API
  local api_runners
  api_runners=$(gitea_api GET "/admin/runners" 2>/dev/null || echo "[]")

  # Print header
  printf '%-20s %-16s %-10s %-8s %-10s\n' "NAME" "HOST" "LABELS" "TYPE" "STATUS"
  printf '%-20s %-16s %-10s %-8s %-10s\n' "----" "----" "------" "----" "------"

  # For each entry in runners.conf, look up status in API response
  while IFS='|' read -r name host user port path labels type; do
    # Skip comments and blank lines
    [[ "$name" =~ ^[[:space:]]*# ]] && continue
    [[ -z "$name" ]] && continue

    name=$(echo "$name" | xargs)
    host=$(echo "$host" | xargs)
    labels=$(echo "$labels" | xargs)
    type=$(echo "$type" | xargs)

    # Search for this runner in the API response by name
    local status
    status=$(printf '%s' "$api_runners" | jq -r --arg n "$name" '.[] | select(.name == $n) | .status' 2>/dev/null || true)

    if [[ -z "$status" ]]; then
      status="not-found"
    fi

    printf '%-20s %-16s %-10s %-8s %-10s\n' "$name" "$host" "$labels" "$type" "$status"
  done < "$RUNNERS_CONF"
}

# ---------------------------------------------------------------------------
# Main — parse command and dispatch
# ---------------------------------------------------------------------------
COMMAND=""
RUNNER_ARG_NAME=""

while [[ $# -gt 0 ]]; do
  case "$1" in
    add|remove|list) COMMAND="$1"; shift ;;
    --name)
      if [[ $# -lt 2 ]]; then log_error "--name requires a value"; usage; fi
      RUNNER_ARG_NAME="$2"; shift 2 ;;
    --help|-h) usage ;;
    *) log_error "Unknown argument: $1"; usage ;;
  esac
done

if [[ -z "$COMMAND" ]]; then
  log_error "No command specified"
  usage
fi

case "$COMMAND" in
  add)
    if [[ -z "$RUNNER_ARG_NAME" ]]; then
      log_error "add requires --name <runner_name>"
      usage
    fi
    require_vars GITEA_RUNNER_REGISTRATION_TOKEN
    parse_runner_entry "$RUNNER_ARG_NAME"
    case "$RUNNER_TYPE" in
      docker) add_docker_runner ;;
      native) add_native_runner ;;
      *) log_error "Unknown runner type: $RUNNER_TYPE (must be 'docker' or 'native')"; exit 1 ;;
    esac
    ;;
  remove)
    if [[ -z "$RUNNER_ARG_NAME" ]]; then
      log_error "remove requires --name <runner_name>"
      usage
    fi
    parse_runner_entry "$RUNNER_ARG_NAME"
    case "$RUNNER_TYPE" in
      docker) remove_docker_runner ;;
      native) remove_native_runner ;;
      *) log_error "Unknown runner type: $RUNNER_TYPE"; exit 1 ;;
    esac
    ;;
  list)
    list_runners
    ;;
  *)
    log_error "Unknown command: $COMMAND"
    usage
    ;;
esac