#!/usr/bin/env bash

set -euo pipefail

resolve_inputs() {
  local service=""
  local target_env=""
  local image_tag=""
  local image_name=""
  local kustomization=""

  if [[ "${GITHUB_EVENT_NAME:-}" == "workflow_dispatch" ]]; then
    service="${INPUT_SERVICE:-}"
    target_env="${INPUT_TARGET_ENV:-}"
    image_tag="${INPUT_IMAGE_TAG:-}"
  else
    service="${EVENT_SERVICE:-}"
    target_env="${EVENT_TARGET_ENV:-}"
    image_tag="${EVENT_IMAGE_TAG:-}"
  fi

  if [[ -z "$service" || -z "$target_env" || -z "$image_tag" ]]; then
    echo "Missing service/target_env/image_tag input" >&2
    exit 1
  fi

  case "$service" in
    auth-server)
      image_name="ghcr.io/donghyeonka/project-auth-server"
      ;;
    api-server)
      image_name="ghcr.io/donghyeonka/project-api-server"
      ;;
    *)
      echo "Unsupported service: $service" >&2
      exit 1
      ;;
  esac

  case "$target_env" in
    dev|prod)
      ;;
    *)
      echo "Unsupported environment: $target_env" >&2
      exit 1
      ;;
  esac

  if [[ ! "$image_tag" =~ ^[A-Za-z0-9][A-Za-z0-9._-]{0,127}$ ]]; then
    echo "Unsupported image tag format: $image_tag" >&2
    exit 1
  fi

  kustomization="apps/${service}/overlays/${target_env}/kustomization.yaml"

  {
    echo "SERVICE=$service"
    echo "TARGET_ENV=$target_env"
    echo "IMAGE_TAG=$image_tag"
    echo "IMAGE_NAME=$image_name"
    echo "KUSTOMIZATION=$kustomization"
  } >> "$GITHUB_ENV"
}

update_kustomization() {
  if ! command -v kustomize >/dev/null 2>&1; then
    echo "kustomize is required to update the image tag" >&2
    exit 1
  fi

  if [[ ! -f "${KUSTOMIZATION:-}" ]]; then
    echo "Kustomization not found: ${KUSTOMIZATION:-}" >&2
    exit 1
  fi

  cd "$(dirname "$KUSTOMIZATION")"
  kustomize edit set image "${IMAGE_NAME}=${IMAGE_NAME}:${IMAGE_TAG}"
}

validate_overlay() {
  if ! command -v kubectl >/dev/null 2>&1; then
    echo "kubectl is required to validate the overlay" >&2
    exit 1
  fi

  kubectl kustomize "$(dirname "$KUSTOMIZATION")" >/dev/null
}

check_changes() {
  if git diff --quiet -- "$KUSTOMIZATION"; then
    echo "changed=false" >> "$GITHUB_OUTPUT"
    echo "No changes to commit"
  else
    echo "changed=true" >> "$GITHUB_OUTPUT"
    git diff -- "$KUSTOMIZATION"
  fi
}

commit_dev() {
  git config user.name "github-actions[bot]"
  git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
  git add "$KUSTOMIZATION"
  git commit -m "chore(gitops): update ${SERVICE} ${TARGET_ENV} image to ${IMAGE_TAG}"
  git push origin "HEAD:${DEFAULT_BRANCH}"
}

main() {
  case "${1:-}" in
    resolve-inputs)
      resolve_inputs
      ;;
    update-kustomization)
      update_kustomization
      ;;
    validate-overlay)
      validate_overlay
      ;;
    check-changes)
      check_changes
      ;;
    commit-dev)
      commit_dev
      ;;
    *)
      echo "Usage: scripts/ci/update-image-tag.sh <resolve-inputs|update-kustomization|validate-overlay|check-changes|commit-dev>" >&2
      exit 1
      ;;
  esac
}

main "$@"