// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

use crate::args::package_json;
use crate::args::CacheSetting;
use crate::cache::FastInsecureHasher;
use crate::graph_util::CliJsrUrlProvider;
use crate::http_util::HttpClient;
use crate::jsr::JsrCacheResolver;
use crate::lsp::config::Config;
use crate::lsp::config::ConfigData;
use crate::npm::create_cli_npm_resolver_for_lsp;
use crate::npm::CliNpmResolver;
use crate::npm::CliNpmResolverByonmCreateOptions;
use crate::npm::CliNpmResolverCreateOptions;
use crate::npm::CliNpmResolverManagedCreateOptions;
use crate::npm::CliNpmResolverManagedPackageJsonInstallerOption;
use crate::npm::CliNpmResolverManagedSnapshotOption;
use crate::npm::ManagedCliNpmResolver;
use crate::resolver::CliGraphResolver;
use crate::resolver::CliGraphResolverOptions;
use crate::resolver::CliNodeResolver;
use crate::resolver::SloppyImportsResolver;
use crate::util::progress_bar::ProgressBar;
use crate::util::progress_bar::ProgressBarStyle;
use dashmap::DashMap;
use deno_ast::MediaType;
use deno_cache_dir::HttpCache;
use deno_core::error::AnyError;
use deno_core::url::Url;
use deno_graph::source::NpmResolver;
use deno_graph::source::Resolver;
use deno_graph::GraphImport;
use deno_graph::ModuleSpecifier;
use deno_npm::NpmSystemInfo;
use deno_runtime::deno_fs;
use deno_runtime::deno_node::NodeResolution;
use deno_runtime::deno_node::NodeResolutionMode;
use deno_runtime::deno_node::NodeResolver;
use deno_runtime::deno_node::PackageJson;
use deno_runtime::fs_util::specifier_to_file_path;
use deno_runtime::permissions::PermissionsContainer;
use deno_semver::jsr::JsrPackageReqReference;
use deno_semver::npm::NpmPackageReqReference;
use deno_semver::package::PackageNv;
use deno_semver::package::PackageReq;
use indexmap::IndexMap;
use package_json::PackageJsonDepsProvider;
use std::borrow::Cow;
use std::collections::HashMap;
use std::collections::HashSet;
use std::rc::Rc;
use std::sync::Arc;

use super::cache::LspCache;

#[derive(Debug, Clone)]
pub struct LspResolver {
  graph_resolver: Arc<CliGraphResolver>,
  jsr_resolver: Option<Arc<JsrCacheResolver>>,
  npm_resolver: Option<Arc<dyn CliNpmResolver>>,
  node_resolver: Option<Arc<CliNodeResolver>>,
  npm_config_hash: LspNpmConfigHash,
  redirect_resolver: Option<Arc<RedirectResolver>>,
  graph_imports: Arc<IndexMap<ModuleSpecifier, GraphImport>>,
  config: Arc<Config>,
}

impl Default for LspResolver {
  fn default() -> Self {
    Self {
      graph_resolver: create_graph_resolver(None, None, None),
      jsr_resolver: None,
      npm_resolver: None,
      node_resolver: None,
      npm_config_hash: LspNpmConfigHash(0),
      redirect_resolver: None,
      graph_imports: Default::default(),
      config: Default::default(),
    }
  }
}

impl LspResolver {
  pub async fn with_new_config(
    &self,
    config: &Config,
    cache: &LspCache,
    http_client: Option<&Arc<HttpClient>>,
  ) -> Arc<Self> {
    let npm_config_hash = LspNpmConfigHash::new(config, cache);
    let config_data = config.tree.root_data();
    let mut npm_resolver = None;
    let mut node_resolver = None;
    if npm_config_hash != self.npm_config_hash {
      if let (Some(http_client), Some(config_data)) = (http_client, config_data)
      {
        npm_resolver =
          create_npm_resolver(config_data, cache, http_client).await;
        node_resolver = create_node_resolver(npm_resolver.as_ref());
      }
    } else {
      npm_resolver = self.npm_resolver.clone();
      node_resolver = self.node_resolver.clone();
    }
    let graph_resolver = create_graph_resolver(
      config_data,
      npm_resolver.as_ref(),
      node_resolver.as_ref(),
    );
    let jsr_resolver = Some(Arc::new(JsrCacheResolver::new(
      cache.root_vendor_or_global(),
      config_data.and_then(|d| d.lockfile.clone()),
    )));
    let redirect_resolver = Some(Arc::new(RedirectResolver::new(
      cache.root_vendor_or_global(),
    )));
    let graph_imports = config_data
      .and_then(|d| d.config_file.as_ref())
      .and_then(|cf| cf.to_maybe_imports().ok())
      .map(|imports| {
        Arc::new(
          imports
            .into_iter()
            .map(|(referrer, imports)| {
              let graph_import = GraphImport::new(
                &referrer,
                imports,
                &CliJsrUrlProvider,
                Some(graph_resolver.as_ref()),
                Some(graph_resolver.as_ref()),
              );
              (referrer, graph_import)
            })
            .collect(),
        )
      })
      .unwrap_or_default();
    Arc::new(Self {
      graph_resolver,
      jsr_resolver,
      npm_resolver,
      node_resolver,
      npm_config_hash,
      redirect_resolver,
      graph_imports,
      config: Arc::new(config.clone()),
    })
  }

  pub fn snapshot(&self) -> Arc<Self> {
    let npm_resolver =
      self.npm_resolver.as_ref().map(|r| r.clone_snapshotted());
    let node_resolver = create_node_resolver(npm_resolver.as_ref());
    let graph_resolver = create_graph_resolver(
      self.config.tree.root_data(),
      npm_resolver.as_ref(),
      node_resolver.as_ref(),
    );
    Arc::new(Self {
      graph_resolver,
      jsr_resolver: self.jsr_resolver.clone(),
      npm_resolver,
      node_resolver,
      npm_config_hash: self.npm_config_hash.clone(),
      redirect_resolver: self.redirect_resolver.clone(),
      graph_imports: self.graph_imports.clone(),
      config: self.config.clone(),
    })
  }

  pub fn did_cache(&self) {
    self.jsr_resolver.as_ref().inspect(|r| r.did_cache());
  }

  pub async fn set_npm_package_reqs(
    &self,
    reqs: &[PackageReq],
  ) -> Result<(), AnyError> {
    if let Some(npm_resolver) = self.npm_resolver.as_ref() {
      if let Some(npm_resolver) = npm_resolver.as_managed() {
        return npm_resolver.set_package_reqs(reqs).await;
      }
    }
    Ok(())
  }

  pub fn as_graph_resolver(&self) -> &dyn Resolver {
    self.graph_resolver.as_ref()
  }

  pub fn as_graph_npm_resolver(&self) -> &dyn NpmResolver {
    self.graph_resolver.as_ref()
  }

  pub fn maybe_managed_npm_resolver(&self) -> Option<&ManagedCliNpmResolver> {
    self.npm_resolver.as_ref().and_then(|r| r.as_managed())
  }

  pub fn graph_import_specifiers(
    &self,
  ) -> impl Iterator<Item = &ModuleSpecifier> {
    self
      .graph_imports
      .values()
      .flat_map(|i| i.dependencies.values())
      .flat_map(|value| value.get_type().or_else(|| value.get_code()))
  }

  pub fn jsr_to_registry_url(
    &self,
    req_ref: &JsrPackageReqReference,
  ) -> Option<ModuleSpecifier> {
    self.jsr_resolver.as_ref()?.jsr_to_registry_url(req_ref)
  }

  pub fn jsr_lookup_export_for_path(
    &self,
    nv: &PackageNv,
    path: &str,
  ) -> Option<String> {
    self.jsr_resolver.as_ref()?.lookup_export_for_path(nv, path)
  }

  pub fn jsr_lookup_req_for_nv(&self, nv: &PackageNv) -> Option<PackageReq> {
    self.jsr_resolver.as_ref()?.lookup_req_for_nv(nv)
  }

  pub fn npm_to_file_url(
    &self,
    req_ref: &NpmPackageReqReference,
    referrer: &ModuleSpecifier,
    mode: NodeResolutionMode,
  ) -> Option<(ModuleSpecifier, MediaType)> {
    let node_resolver = self.node_resolver.as_ref()?;
    Some(NodeResolution::into_specifier_and_media_type(
      node_resolver
        .resolve_req_reference(
          req_ref,
          &PermissionsContainer::allow_all(),
          referrer,
          mode,
        )
        .ok(),
    ))
  }

  pub fn in_node_modules(&self, specifier: &ModuleSpecifier) -> bool {
    if let Some(npm_resolver) = &self.npm_resolver {
      return npm_resolver.in_npm_package(specifier);
    }
    false
  }

  pub fn node_media_type(
    &self,
    specifier: &ModuleSpecifier,
  ) -> Option<MediaType> {
    let node_resolver = self.node_resolver.as_ref()?;
    let resolution = node_resolver
      .url_to_node_resolution(specifier.clone())
      .ok()?;
    Some(NodeResolution::into_specifier_and_media_type(Some(resolution)).1)
  }

  pub fn get_closest_package_json(
    &self,
    referrer: &ModuleSpecifier,
  ) -> Result<Option<Rc<PackageJson>>, AnyError> {
    let Some(node_resolver) = self.node_resolver.as_ref() else {
      return Ok(None);
    };
    node_resolver
      .get_closest_package_json(referrer, &PermissionsContainer::allow_all())
  }

  pub fn resolve_redirects(
    &self,
    specifier: &ModuleSpecifier,
  ) -> Option<ModuleSpecifier> {
    let Some(redirect_resolver) = self.redirect_resolver.as_ref() else {
      return Some(specifier.clone());
    };
    redirect_resolver.resolve(specifier)
  }

  pub fn redirect_chain_headers(
    &self,
    specifier: &ModuleSpecifier,
  ) -> Vec<(ModuleSpecifier, Arc<HashMap<String, String>>)> {
    let Some(redirect_resolver) = self.redirect_resolver.as_ref() else {
      return vec![];
    };
    redirect_resolver
      .chain(specifier)
      .into_iter()
      .map(|(s, e)| (s, e.headers.clone()))
      .collect()
  }
}

async fn create_npm_resolver(
  config_data: &ConfigData,
  cache: &LspCache,
  http_client: &Arc<HttpClient>,
) -> Option<Arc<dyn CliNpmResolver>> {
  let node_modules_dir = config_data
    .node_modules_dir
    .clone()
    .or_else(|| specifier_to_file_path(&config_data.scope).ok())?;
  let options = if config_data.byonm {
    CliNpmResolverCreateOptions::Byonm(CliNpmResolverByonmCreateOptions {
      fs: Arc::new(deno_fs::RealFs),
      root_node_modules_dir: node_modules_dir,
    })
  } else {
    CliNpmResolverCreateOptions::Managed(CliNpmResolverManagedCreateOptions {
      http_client: http_client.clone(),
      snapshot: match config_data.lockfile.as_ref() {
        Some(lockfile) => {
          CliNpmResolverManagedSnapshotOption::ResolveFromLockfile(
            lockfile.clone(),
          )
        }
        None => CliNpmResolverManagedSnapshotOption::Specified(None),
      },
      // Don't provide the lockfile. We don't want these resolvers
      // updating it. Only the cache request should update the lockfile.
      maybe_lockfile: None,
      fs: Arc::new(deno_fs::RealFs),
      npm_global_cache_dir: cache.deno_dir().npm_folder_path(),
      // Use an "only" cache setting in order to make the
      // user do an explicit "cache" command and prevent
      // the cache from being filled with lots of packages while
      // the user is typing.
      cache_setting: CacheSetting::Only,
      text_only_progress_bar: ProgressBar::new(ProgressBarStyle::TextOnly),
      maybe_node_modules_path: config_data.node_modules_dir.clone(),
      // do not install while resolving in the lsp—leave that to the cache command
      package_json_installer:
        CliNpmResolverManagedPackageJsonInstallerOption::NoInstall,
      npm_registry_url: crate::args::npm_registry_url().to_owned(),
      npm_system_info: NpmSystemInfo::default(),
    })
  };
  Some(create_cli_npm_resolver_for_lsp(options).await)
}

fn create_node_resolver(
  npm_resolver: Option<&Arc<dyn CliNpmResolver>>,
) -> Option<Arc<CliNodeResolver>> {
  let npm_resolver = npm_resolver?;
  let fs = Arc::new(deno_fs::RealFs);
  let node_resolver_inner = Arc::new(NodeResolver::new(
    fs.clone(),
    npm_resolver.clone().into_npm_resolver(),
  ));
  Some(Arc::new(CliNodeResolver::new(
    None,
    fs,
    node_resolver_inner,
    npm_resolver.clone(),
  )))
}

fn create_graph_resolver(
  config_data: Option<&ConfigData>,
  npm_resolver: Option<&Arc<dyn CliNpmResolver>>,
  node_resolver: Option<&Arc<CliNodeResolver>>,
) -> Arc<CliGraphResolver> {
  let config_file = config_data.and_then(|d| d.config_file.as_deref());
  let unstable_sloppy_imports =
    config_file.is_some_and(|cf| cf.has_unstable("sloppy-imports"));
  Arc::new(CliGraphResolver::new(CliGraphResolverOptions {
    node_resolver: node_resolver.cloned(),
    npm_resolver: npm_resolver.cloned(),
    package_json_deps_provider: Arc::new(PackageJsonDepsProvider::new(
      config_data
        .and_then(|d| d.package_json.as_ref())
        .map(|package_json| {
          package_json::get_local_package_json_version_reqs(package_json)
        }),
    )),
    maybe_jsx_import_source_config: config_file
      .and_then(|cf| cf.to_maybe_jsx_import_source_config().ok().flatten()),
    maybe_import_map: config_data.and_then(|d| d.import_map.clone()),
    maybe_vendor_dir: config_data.and_then(|d| d.vendor_dir.as_ref()),
    bare_node_builtins_enabled: config_file
      .map(|cf| cf.has_unstable("bare-node-builtins"))
      .unwrap_or(false),
    sloppy_imports_resolver: unstable_sloppy_imports.then(|| {
      SloppyImportsResolver::new_without_stat_cache(Arc::new(deno_fs::RealFs))
    }),
  }))
}

#[derive(Debug, Clone, PartialEq, Eq)]
struct LspNpmConfigHash(u64);

impl LspNpmConfigHash {
  pub fn new(config: &Config, cache: &LspCache) -> Self {
    let config_data = config.tree.root_data();
    let scope = config_data.map(|d| &d.scope);
    let node_modules_dir =
      config_data.and_then(|d| d.node_modules_dir.as_ref());
    let lockfile = config_data.and_then(|d| d.lockfile.as_ref());
    let mut hasher = FastInsecureHasher::new();
    hasher.write_hashable(scope);
    hasher.write_hashable(node_modules_dir);
    if let Some(lockfile) = lockfile {
      hasher.write_hashable(&*lockfile.lock());
    }
    hasher.write_hashable(cache.deno_dir().npm_folder_path());
    Self(hasher.finish())
  }
}

#[derive(Debug, Eq, PartialEq)]
struct RedirectEntry {
  headers: Arc<HashMap<String, String>>,
  target: Url,
  destination: Option<Url>,
}

type GetHeadersFn =
  Box<dyn Fn(&Url) -> Option<HashMap<String, String>> + Send + Sync>;

struct RedirectResolver {
  get_headers: GetHeadersFn,
  entries: DashMap<Url, Option<Arc<RedirectEntry>>>,
}

impl std::fmt::Debug for RedirectResolver {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    f.debug_struct("RedirectResolver")
      .field("get_headers", &"Box(|_| { ... })")
      .field("entries", &self.entries)
      .finish()
  }
}

impl RedirectResolver {
  fn new(cache: Arc<dyn HttpCache>) -> Self {
    Self {
      get_headers: Box::new(move |specifier| {
        let cache_key = cache.cache_item_key(specifier).ok()?;
        cache.read_headers(&cache_key).ok().flatten()
      }),
      entries: Default::default(),
    }
  }

  #[cfg(test)]
  fn mock(get_headers: GetHeadersFn) -> Self {
    Self {
      get_headers,
      entries: Default::default(),
    }
  }

  fn resolve(&self, specifier: &Url) -> Option<Url> {
    if !matches!(specifier.scheme(), "http" | "https") {
      return Some(specifier.clone());
    }
    let mut current = specifier.clone();
    let mut chain = vec![];
    let destination = loop {
      if let Some(maybe_entry) = self.entries.get(&current) {
        break match maybe_entry.as_ref() {
          Some(entry) => entry.destination.clone(),
          None => Some(current),
        };
      }
      let Some(headers) = (self.get_headers)(&current) else {
        break None;
      };
      let headers = Arc::new(headers);
      if let Some(location) = headers.get("location") {
        if chain.len() > 10 {
          break None;
        }
        let Ok(target) =
          deno_core::resolve_import(location, specifier.as_str())
        else {
          break None;
        };
        chain.push((
          current.clone(),
          RedirectEntry {
            headers,
            target: target.clone(),
            destination: None,
          },
        ));
        current = target;
      } else {
        self.entries.insert(current.clone(), None);
        break Some(current);
      }
    };
    for (specifier, mut entry) in chain {
      entry.destination = destination.clone();
      self.entries.insert(specifier, Some(Arc::new(entry)));
    }
    destination
  }

  fn chain(&self, specifier: &Url) -> Vec<(Url, Arc<RedirectEntry>)> {
    self.resolve(specifier);
    let mut result = vec![];
    let mut seen = HashSet::new();
    let mut current = Cow::Borrowed(specifier);
    loop {
      let Some(maybe_entry) = self.entries.get(&current) else {
        break;
      };
      let Some(entry) = maybe_entry.as_ref() else {
        break;
      };
      result.push((current.as_ref().clone(), entry.clone()));
      seen.insert(current.as_ref().clone());
      if seen.contains(&entry.target) {
        break;
      }
      current = Cow::Owned(entry.target.clone())
    }
    result
  }
}

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn test_redirect_resolver() {
    let redirect_resolver =
      RedirectResolver::mock(Box::new(|specifier| match specifier.as_str() {
        "https://foo/redirect_2.js" => Some(
          [("location".to_string(), "./redirect_1.js".to_string())]
            .into_iter()
            .collect(),
        ),
        "https://foo/redirect_1.js" => Some(
          [("location".to_string(), "./file.js".to_string())]
            .into_iter()
            .collect(),
        ),
        "https://foo/file.js" => Some([].into_iter().collect()),
        _ => None,
      }));
    assert_eq!(
      redirect_resolver.resolve(&Url::parse("https://foo/file.js").unwrap()),
      Some(Url::parse("https://foo/file.js").unwrap())
    );
    assert_eq!(
      redirect_resolver
        .resolve(&Url::parse("https://foo/redirect_1.js").unwrap()),
      Some(Url::parse("https://foo/file.js").unwrap())
    );
    assert_eq!(
      redirect_resolver
        .resolve(&Url::parse("https://foo/redirect_2.js").unwrap()),
      Some(Url::parse("https://foo/file.js").unwrap())
    );
    assert_eq!(
      redirect_resolver.resolve(&Url::parse("https://foo/unknown").unwrap()),
      None
    );
    assert_eq!(
      redirect_resolver
        .chain(&Url::parse("https://foo/redirect_2.js").unwrap()),
      vec![
        (
          Url::parse("https://foo/redirect_2.js").unwrap(),
          Arc::new(RedirectEntry {
            headers: Arc::new(
              [("location".to_string(), "./redirect_1.js".to_string())]
                .into_iter()
                .collect()
            ),
            target: Url::parse("https://foo/redirect_1.js").unwrap(),
            destination: Some(Url::parse("https://foo/file.js").unwrap()),
          })
        ),
        (
          Url::parse("https://foo/redirect_1.js").unwrap(),
          Arc::new(RedirectEntry {
            headers: Arc::new(
              [("location".to_string(), "./file.js".to_string())]
                .into_iter()
                .collect()
            ),
            target: Url::parse("https://foo/file.js").unwrap(),
            destination: Some(Url::parse("https://foo/file.js").unwrap()),
          })
        ),
      ]
    );
  }
}