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

SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
REPO_ROOT=$(cd -- "$SCRIPT_DIR/.." && pwd)

validate_instance() {
  local instance=$1

  if [[ ${#instance} -gt 42 || ! $instance =~ ^[a-z0-9]([a-z0-9-]*[a-z0-9])?$ ]]; then
    echo "instance must be 1-42 lowercase letters, digits, or internal hyphens: $instance" >&2
    exit 2
  fi
}

sync_tree() {
  local source_dir=$1
  local destination=$2

  mkdir -p -- "$destination"
  find "$destination" -mindepth 1 -maxdepth 1 -exec rm -rf -- {} +
  cp -a -- "$source_dir/." "$destination/"
}

source_signature() {
  local source_dir=$1

  find "$source_dir" -printf '%P\0%y\0%s\0%T@\0%l\0' | sort -z | sha256sum
}

is_sync_process() {
  local pid=$1
  local instance=$2
  local command

  [[ $pid =~ ^[0-9]+$ && -r /proc/$pid/cmdline ]] || return 1
  command=$(tr '\0' ' ' <"/proc/$pid/cmdline")
  [[ $command == *"start.sh __sync $instance "* ]]
}

if [[ ${1:-} == "__sync" ]]; then
  instance=${2:?missing instance}
  source_dir=${3:?missing source directory}
  destination=${4:?missing destination}
  validate_instance "$instance"

  previous_signature=$(source_signature "$source_dir")
  while true; do
    sleep 1
    current_signature=$(source_signature "$source_dir")
    if [[ $current_signature != "$previous_signature" ]]; then
      sync_tree "$source_dir" "$destination"
      previous_signature=$current_signature
    fi
  done
fi

default_instance=$(basename -- "$REPO_ROOT" | tr '[:upper:]_' '[:lower:]-')
instance=${1:-$default_instance}
validate_instance "$instance"

namespace=${DEV_NAMESPACE:-vibes}
pvc=${DEV_PVC:-control-vibes-control-data}
shared_root=${DEV_SHARED_ROOT:-/data/live}
pvc_subpath_root=${DEV_PVC_SUBPATH_ROOT:-live}
domain=${DEV_DOMAIN:-control.k.mancave.link}
host=${2:-$instance.$domain}
release="hello-dev-$instance"
source_dir="$REPO_ROOT/src"
destination="$shared_root/$instance"
state_dir="$shared_root/.hello-dev-state"
pid_file="$state_dir/$instance.pid"
log_file="$state_dir/$instance.log"

if [[ ! -d $source_dir ]]; then
  echo "source directory does not exist: $source_dir" >&2
  exit 1
fi

if [[ $shared_root != /* || $shared_root == / ]]; then
  echo "DEV_SHARED_ROOT must be an absolute directory below /: $shared_root" >&2
  exit 2
fi

if [[ ! $host =~ ^[a-z0-9]([a-z0-9.-]*[a-z0-9])?$ ]]; then
  echo "invalid hostname: $host" >&2
  exit 2
fi

mkdir -p -- "$state_dir"

if [[ -f $pid_file ]]; then
  old_pid=$(<"$pid_file")
  if is_sync_process "$old_pid" "$instance"; then
    kill "$old_pid"
    wait "$old_pid" 2>/dev/null || true
  fi
  rm -f -- "$pid_file"
fi

sync_tree "$source_dir" "$destination"
nohup "$SCRIPT_DIR/start.sh" __sync "$instance" "$source_dir" "$destination" \
  >"$log_file" 2>&1 &
sync_pid=$!
printf '%s\n' "$sync_pid" >"$pid_file"

cleanup_failed_start() {
  kill "$sync_pid" 2>/dev/null || true
  rm -f -- "$pid_file"
}
trap cleanup_failed_start ERR

helm template "$release" "$SCRIPT_DIR/helm" \
  --namespace "$namespace" \
  --set-string "instance=$instance" \
  --set-string "ingress.host=$host" \
  --set-string "sharedVolume.claimName=$pvc" \
  --set-string "sharedVolume.subPath=$pvc_subpath_root/$instance" \
  | kubectl apply --namespace "$namespace" -f -

kubectl rollout status "deployment/$release" --namespace "$namespace" --timeout=120s
trap - ERR

echo "Development instance '$instance' is live at http://$host"