use crate::artifacts::{
  DatabaseName as DatabaseNameArtifact, Path as PathArtifact, ServiceName as ServiceNameArtifact,
  UserName as UserNameArtifact,
};
use crate::resources::{
  AcmeAccountKey, AcmeChallengesDir, AcmeChallengesNginxSnippet, AcmeRootCert, AcmeUser, Cert,
  CertChain, Cron, Csr, DefaultServer, Dir, File, GitCheckout, Key, KeyAndCertBundle,
  LoadedDirectory, MariaDbDatabase, MariaDbUser, NpmInstall, Owner, PhpFpmPool, Resource,
  ServeCustom, ServePhp, ServeRedir, ServeService, ServeStatic, StoredDirectory,
  SystemdSocketService, User, UserForDomain, WordpressPlugin, WordpressTranslation,
};
use crate::to_artifact::ToArtifact;
use std::fmt::Display;
use std::marker::PhantomData;
use std::path::{Path, PathBuf};

pub trait Policy {
  fn acme_user() -> &'static str {
    "acme"
  }
  fn user_home(user_name: &str) -> PathBuf {
    format!("/home/{}", user_name).into()
  }

  fn user_name_for_domain(domain_name: &'_ str) -> String {
    domain_name.split('.').rev().fold(String::new(), |result, part| if result.is_empty() { result } else { result + "_" } + part)
  }

  fn php_version() -> &'static str {
    "7.0"
  }

  fn path_for_data(name: impl Display) -> PathBuf {
    ("/root/data".as_ref() as &Path).join(format!("_{}", name))
  }
}

pub struct DefaultPolicy;

impl Policy for DefaultPolicy {}

pub trait ResourceLocator<R> {
  type Prerequisites: ToArtifact;
  fn locate(resource: &R) -> (R::Artifact, Self::Prerequisites)
  where
    R: Resource;
}

pub struct DefaultLocator<P = DefaultPolicy> {
  phantom: PhantomData<P>,
}

impl<P, D: AsRef<str>> ResourceLocator<Key<D>> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(resource: &Key<D>) -> (<Key<D> as Resource>::Artifact, Self::Prerequisites) {
    (
      PathArtifact::from(format!("/etc/ssl/private/{}.key", resource.0.as_ref())),
      Dir("/etc/ssl/private".into()),
    )
  }
}

impl<P, D: AsRef<str>> ResourceLocator<Csr<D>> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(resource: &Csr<D>) -> (<Csr<D> as Resource>::Artifact, Self::Prerequisites) {
    (
      PathArtifact::from(format!("/etc/ssl/local_certs/{}.csr", resource.0.as_ref())),
      Dir("/etc/ssl/local_certs".into()),
    )
  }
}

impl<P, D: AsRef<str>> ResourceLocator<Cert<D>> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(resource: &Cert<D>) -> (<Cert<D> as Resource>::Artifact, Self::Prerequisites) {
    (
      PathArtifact::from(format!("/etc/ssl/local_certs/{}.crt", resource.0.as_ref())),
      Dir("/etc/ssl/local_certs".into()),
    )
  }
}

impl<P, D: AsRef<str>> ResourceLocator<CertChain<D>> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(
    resource: &CertChain<D>,
  ) -> (<CertChain<D> as Resource>::Artifact, Self::Prerequisites) {
    (
      PathArtifact::from(format!(
        "/etc/ssl/local_certs/{}.chained.crt",
        resource.0.as_ref()
      )),
      Dir("/etc/ssl/local_certs".into()),
    )
  }
}

impl<P, D: AsRef<str>> ResourceLocator<KeyAndCertBundle<D>> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(
    resource: &KeyAndCertBundle<D>,
  ) -> (
    <KeyAndCertBundle<D> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    (
      PathArtifact::from(format!(
        "/etc/ssl/private/{}.with_key.crt",
        resource.0.as_ref()
      )),
      Dir("/etc/ssl/private".into()),
    )
  }
}

impl<'a, POLICY, P: AsRef<Path>> ResourceLocator<File<P>> for DefaultLocator<POLICY> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(resource: &File<P>) -> (<File<P> as Resource>::Artifact, Self::Prerequisites) {
    ((), Dir(resource.0.as_ref().parent().unwrap().into()))
  }
}

impl<'a, POLICY, P: AsRef<Path>> ResourceLocator<GitCheckout<'a, P>> for DefaultLocator<POLICY> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(
    resource: &GitCheckout<'a, P>,
  ) -> (
    <GitCheckout<'a, P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    ((), Dir(resource.0.as_ref().parent().unwrap().into()))
  }
}

impl<POLICY, P: Clone + AsRef<Path>> ResourceLocator<Dir<P>> for DefaultLocator<POLICY> {
  type Prerequisites = Option<Dir<PathBuf>>;
  fn locate(resource: &Dir<P>) -> (<Dir<P> as Resource>::Artifact, Self::Prerequisites) {
    ((), resource.0.as_ref().parent().map(|p| Dir(p.into())))
  }
}

impl<POLICY, P> ResourceLocator<NpmInstall<P>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    _resource: &NpmInstall<P>,
  ) -> (<NpmInstall<P> as Resource>::Artifact, Self::Prerequisites) {
    ((), ())
  }
}

impl<POLICY: Policy, P: AsRef<Path>> ResourceLocator<StoredDirectory<P>>
  for DefaultLocator<POLICY>
{
  type Prerequisites = ();
  fn locate(
    resource: &StoredDirectory<P>,
  ) -> (
    <StoredDirectory<P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    (PathArtifact::from(POLICY::path_for_data(resource.0)), ())
  }
}

impl<POLICY: Policy, P: AsRef<Path>> ResourceLocator<LoadedDirectory<P>>
  for DefaultLocator<POLICY>
{
  type Prerequisites = Dir<PathBuf>;
  fn locate(
    resource: &LoadedDirectory<P>,
  ) -> (
    <LoadedDirectory<P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    (
      PathArtifact::from(POLICY::path_for_data(resource.0)),
      Dir(resource.1.as_ref().parent().unwrap().into()),
    )
  }
}

impl<P: Policy> ResourceLocator<AcmeAccountKey> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(
    _resource: &AcmeAccountKey,
  ) -> (<AcmeAccountKey as Resource>::Artifact, Self::Prerequisites) {
    let acme_user = P::acme_user();
    let home = P::user_home(acme_user);
    (PathArtifact::from(home.join("account.key")), Dir(home))
  }
}

impl<P: Policy> ResourceLocator<AcmeUser> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(_resource: &AcmeUser) -> (<AcmeUser as Resource>::Artifact, Self::Prerequisites) {
    let acme_user = P::acme_user();
    (UserNameArtifact(acme_user.into()), ())
  }
}

impl<P: Policy> ResourceLocator<AcmeChallengesDir> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(
    _resource: &AcmeChallengesDir,
  ) -> (
    <AcmeChallengesDir as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    let acme_user = P::acme_user();
    let home = P::user_home(acme_user);
    (PathArtifact::from(home.join("challenges")), Dir(home))
  }
}

impl<P: Policy> ResourceLocator<AcmeChallengesNginxSnippet> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(
    _resource: &AcmeChallengesNginxSnippet,
  ) -> (
    <AcmeChallengesNginxSnippet as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    (
      PathArtifact::from("/etc/nginx/snippets/acme-challenge.conf"),
      (),
    )
  }
}

impl<P: Policy> ResourceLocator<AcmeRootCert> for DefaultLocator<P> {
  type Prerequisites = Dir<PathBuf>;
  fn locate(
    _resource: &AcmeRootCert,
  ) -> (<AcmeRootCert as Resource>::Artifact, Self::Prerequisites) {
    let acme_user = P::acme_user();
    let home = P::user_home(acme_user);
    (
      PathArtifact::from(home.join("lets_encrypt_x3_cross_signed.pem")),
      Dir(home),
    )
  }
}

impl<P: Policy, D: AsRef<str>> ResourceLocator<UserForDomain<D>> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(
    resource: &UserForDomain<D>,
  ) -> (
    <UserForDomain<D> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    let user_name = P::user_name_for_domain(resource.0.as_ref());
    let home = P::user_home(&user_name);
    ((UserNameArtifact(user_name), PathArtifact::from(home)), ())
  }
}

impl<P> ResourceLocator<User> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(_resource: &User) -> (<User as Resource>::Artifact, Self::Prerequisites) {
    ((), ())
  }
}

impl<P, POLICY> ResourceLocator<Owner<P>> for DefaultLocator<POLICY> {
  type Prerequisites = User;
  fn locate(resource: &Owner<P>) -> (<Owner<P> as Resource>::Artifact, Self::Prerequisites) {
    ((), User(resource.0.clone()))
  }
}

impl<P> ResourceLocator<DefaultServer> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(
    _resource: &DefaultServer,
  ) -> (<DefaultServer as Resource>::Artifact, Self::Prerequisites) {
    (PathArtifact::from("/etc/nginx/sites-enabled/default"), ())
  }
}

impl<D: AsRef<Path>, POLICY> ResourceLocator<ServeCustom<D>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    resource: &ServeCustom<D>,
  ) -> (<ServeCustom<D> as Resource>::Artifact, Self::Prerequisites) {
    (
      PathArtifact::from(("/etc/nginx/sites-enabled/".as_ref() as &Path).join(&resource.0)),
      (),
    )
  }
}

impl<D: AsRef<Path>, P, POLICY> ResourceLocator<ServePhp<D, P>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    resource: &ServePhp<D, P>,
  ) -> (<ServePhp<D, P> as Resource>::Artifact, Self::Prerequisites) {
    (
      PathArtifact::from(("/etc/nginx/sites-enabled/".as_ref() as &Path).join(&resource.0)),
      (),
    )
  }
}

impl<D: AsRef<Path>, P, POLICY> ResourceLocator<ServeService<D, P>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    resource: &ServeService<D, P>,
  ) -> (
    <ServeService<D, P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    (
      PathArtifact::from(("/etc/nginx/sites-enabled/".as_ref() as &Path).join(&resource.0)),
      (),
    )
  }
}

impl<D: AsRef<Path>, POLICY> ResourceLocator<ServeRedir<D>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    resource: &ServeRedir<D>,
  ) -> (<ServeRedir<D> as Resource>::Artifact, Self::Prerequisites) {
    (
      PathArtifact::from(("/etc/nginx/sites-enabled/".as_ref() as &Path).join(&resource.0)),
      (),
    )
  }
}

impl<D: AsRef<Path>, P, POLICY> ResourceLocator<ServeStatic<D, P>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    resource: &ServeStatic<D, P>,
  ) -> (
    <ServeStatic<D, P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    (
      PathArtifact::from(("/etc/nginx/sites-enabled/".as_ref() as &Path).join(&resource.0)),
      (),
    )
  }
}

impl<D: Clone + AsRef<str>, P: Policy> ResourceLocator<PhpFpmPool<D>> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(
    resource: &PhpFpmPool<D>,
  ) -> (<PhpFpmPool<D> as Resource>::Artifact, Self::Prerequisites) {
    let ((user, _), ()) = Self::locate(&UserForDomain(&resource.0));
    let php_version = P::php_version();
    (
      (
        PathArtifact::from(format!("/run/php/{}.sock", user.0)),
        PathArtifact::from(format!(
          "/etc/php/{}/fpm/pool.d/{}.conf",
          php_version, user.0
        )),
        user,
        ServiceNameArtifact(format!("php{}-fpm", php_version)),
      ),
      (),
    )
  }
}

impl<D: Clone + AsRef<str>, P, POLICY: Policy> ResourceLocator<SystemdSocketService<D, P>>
  for DefaultLocator<POLICY>
{
  type Prerequisites = (Dir<PathBuf>, Owner<PathBuf>);
  fn locate(
    resource: &SystemdSocketService<D, P>,
  ) -> (
    <SystemdSocketService<D, P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    let ((user_name, home_path), ()) = Self::locate(&UserForDomain(&resource.0));
    let config = home_path.as_ref().join(".config");
    let service_dir_path = config.join("systemd/user");
    (
      (
        PathArtifact::from(format!("/var/tmp/{}-{}.socket", user_name.0, resource.1)),
        PathArtifact::from(service_dir_path.join(format!("{}.service", resource.1))),
        user_name.clone(),
      ),
      (Dir(service_dir_path), Owner(user_name.0, config)),
    )
  }
}

impl<D: AsRef<str>, P: Policy> ResourceLocator<MariaDbDatabase<D>> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(
    resource: &MariaDbDatabase<D>,
  ) -> (
    <MariaDbDatabase<D> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    let ((user_name, _), ()) = Self::locate(&UserForDomain(&resource.0));
    (
      (
        DatabaseNameArtifact(user_name.0.clone()),
        user_name.clone(),
        PathArtifact::from(P::path_for_data(format!("{}.sql", user_name.0))),
      ),
      (),
    )
  }
}

impl<D: AsRef<str>, P: Policy> ResourceLocator<MariaDbUser<D>> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(
    resource: &MariaDbUser<D>,
  ) -> (<MariaDbUser<D> as Resource>::Artifact, Self::Prerequisites) {
    let ((user_name, _), ()) = Self::locate(&UserForDomain(&resource.0));
    ((user_name), ())
  }
}

impl<P, POLICY> ResourceLocator<WordpressPlugin<P>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    _resource: &WordpressPlugin<P>,
  ) -> (
    <WordpressPlugin<P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    ((), ())
  }
}

impl<P, POLICY> ResourceLocator<WordpressTranslation<P>> for DefaultLocator<POLICY> {
  type Prerequisites = ();
  fn locate(
    _resource: &WordpressTranslation<P>,
  ) -> (
    <WordpressTranslation<P> as Resource>::Artifact,
    Self::Prerequisites,
  ) {
    ((), ())
  }
}

impl<D, P> ResourceLocator<Cron<D>> for DefaultLocator<P> {
  type Prerequisites = ();
  fn locate(_resource: &Cron<D>) -> (<Cron<D> as Resource>::Artifact, Self::Prerequisites) {
    ((), ())
  }
}