// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.

use crate::args::TsConfig;
use crate::node;
use crate::node::node_resolve_npm_reference;
use crate::node::NodeResolution;
use crate::npm::NpmPackageResolver;
use crate::util::checksum;

use deno_ast::MediaType;
use deno_core::anyhow::anyhow;
use deno_core::anyhow::Context;
use deno_core::error::AnyError;
use deno_core::located_script_name;
use deno_core::op;
use deno_core::resolve_url_or_path;
use deno_core::serde::Deserialize;
use deno_core::serde::Deserializer;
use deno_core::serde::Serialize;
use deno_core::serde::Serializer;
use deno_core::serde_json;
use deno_core::serde_json::json;
use deno_core::serde_json::Value;
use deno_core::serde_v8;
use deno_core::Extension;
use deno_core::JsRuntime;
use deno_core::ModuleSpecifier;
use deno_core::OpState;
use deno_core::RuntimeOptions;
use deno_core::Snapshot;
use deno_graph::npm::NpmPackageNvReference;
use deno_graph::npm::NpmPackageReqReference;
use deno_graph::Module;
use deno_graph::ModuleGraph;
use deno_graph::ResolutionResolved;
use deno_runtime::deno_node::NodeResolutionMode;
use deno_runtime::permissions::PermissionsContainer;
use once_cell::sync::Lazy;
use std::borrow::Cow;
use std::collections::HashMap;
use std::fmt;
use std::path::PathBuf;
use std::sync::Arc;

mod diagnostics;

pub use self::diagnostics::Diagnostic;
pub use self::diagnostics::DiagnosticCategory;
pub use self::diagnostics::DiagnosticMessageChain;
pub use self::diagnostics::Diagnostics;
pub use self::diagnostics::Position;

pub static COMPILER_SNAPSHOT: Lazy<Box<[u8]>> = Lazy::new(
  #[cold]
  #[inline(never)]
  || {
    static COMPRESSED_COMPILER_SNAPSHOT: &[u8] =
      include_bytes!(concat!(env!("OUT_DIR"), "/COMPILER_SNAPSHOT.bin"));

    // NOTE(bartlomieju): Compressing the TSC snapshot in debug build took
    // ~45s on M1 MacBook Pro; without compression it took ~1s.
    // Thus we're not not using compressed snapshot, trading off
    // a lot of build time for some startup time in debug build.
    #[cfg(debug_assertions)]
    return COMPRESSED_COMPILER_SNAPSHOT.to_vec().into_boxed_slice();

    #[cfg(not(debug_assertions))]
    zstd::bulk::decompress(
      &COMPRESSED_COMPILER_SNAPSHOT[4..],
      u32::from_le_bytes(COMPRESSED_COMPILER_SNAPSHOT[0..4].try_into().unwrap())
        as usize,
    )
    .unwrap()
    .into_boxed_slice()
  },
);

pub fn get_types_declaration_file_text(unstable: bool) -> String {
  let mut assets = get_asset_texts_from_new_runtime()
    .unwrap()
    .into_iter()
    .map(|a| (a.specifier, a.text))
    .collect::<HashMap<_, _>>();

  let mut lib_names = vec![
    "deno.ns",
    "deno.console",
    "deno.url",
    "deno.web",
    "deno.fetch",
    "deno.webgpu",
    "deno.websocket",
    "deno.webstorage",
    "deno.crypto",
    "deno.broadcast_channel",
    "deno.net",
    "deno.shared_globals",
    "deno.cache",
    "deno.window",
  ];

  if unstable {
    lib_names.push("deno.unstable");
  }

  lib_names
    .into_iter()
    .map(|name| {
      let asset_url = format!("asset:///lib.{name}.d.ts");
      assets.remove(&asset_url).unwrap()
    })
    .collect::<Vec<_>>()
    .join("\n")
}

fn get_asset_texts_from_new_runtime() -> Result<Vec<AssetText>, AnyError> {
  // the assets are stored within the typescript isolate, so take them out of there
  let mut runtime = JsRuntime::new(RuntimeOptions {
    startup_snapshot: Some(compiler_snapshot()),
    extensions: vec![Extension::builder("deno_cli_tsc")
      .ops(get_tsc_ops())
      .build()],
    ..Default::default()
  });
  let global =
    runtime.execute_script("get_assets.js", "globalThis.getAssets()")?;
  let scope = &mut runtime.handle_scope();
  let local = deno_core::v8::Local::new(scope, global);
  Ok(serde_v8::from_v8::<Vec<AssetText>>(scope, local)?)
}

pub fn compiler_snapshot() -> Snapshot {
  Snapshot::Static(&COMPILER_SNAPSHOT)
}

macro_rules! inc {
  ($e:expr) => {
    include_str!(concat!("./dts/", $e))
  };
}

/// Contains static assets that are not preloaded in the compiler snapshot.
///
/// We lazily load these because putting them in the compiler snapshot will
/// increase memory usage when not used (last time checked by about 0.5MB).
pub static LAZILY_LOADED_STATIC_ASSETS: Lazy<
  HashMap<&'static str, &'static str>,
> = Lazy::new(|| {
  ([
    (
      "lib.dom.asynciterable.d.ts",
      inc!("lib.dom.asynciterable.d.ts"),
    ),
    ("lib.dom.d.ts", inc!("lib.dom.d.ts")),
    ("lib.dom.extras.d.ts", inc!("lib.dom.extras.d.ts")),
    ("lib.dom.iterable.d.ts", inc!("lib.dom.iterable.d.ts")),
    ("lib.es6.d.ts", inc!("lib.es6.d.ts")),
    ("lib.es2016.full.d.ts", inc!("lib.es2016.full.d.ts")),
    ("lib.es2017.full.d.ts", inc!("lib.es2017.full.d.ts")),
    ("lib.es2018.full.d.ts", inc!("lib.es2018.full.d.ts")),
    ("lib.es2019.full.d.ts", inc!("lib.es2019.full.d.ts")),
    ("lib.es2020.full.d.ts", inc!("lib.es2020.full.d.ts")),
    ("lib.es2021.full.d.ts", inc!("lib.es2021.full.d.ts")),
    ("lib.es2022.full.d.ts", inc!("lib.es2022.full.d.ts")),
    ("lib.esnext.full.d.ts", inc!("lib.esnext.full.d.ts")),
    ("lib.scripthost.d.ts", inc!("lib.scripthost.d.ts")),
    ("lib.webworker.d.ts", inc!("lib.webworker.d.ts")),
    (
      "lib.webworker.importscripts.d.ts",
      inc!("lib.webworker.importscripts.d.ts"),
    ),
    (
      "lib.webworker.iterable.d.ts",
      inc!("lib.webworker.iterable.d.ts"),
    ),
    (
      // Special file that can be used to inject the @types/node package.
      // This is used for `node:` specifiers.
      "node_types.d.ts",
      "/// <reference types=\"npm:@types/node\" />\n",
    ),
  ])
  .iter()
  .cloned()
  .collect()
});

/// A structure representing stats from a type check operation for a graph.
#[derive(Clone, Debug, Default, Eq, PartialEq)]
pub struct Stats(pub Vec<(String, u32)>);

impl<'de> Deserialize<'de> for Stats {
  fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
  where
    D: Deserializer<'de>,
  {
    let items: Vec<(String, u32)> = Deserialize::deserialize(deserializer)?;
    Ok(Stats(items))
  }
}

impl Serialize for Stats {
  fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
  where
    S: Serializer,
  {
    Serialize::serialize(&self.0, serializer)
  }
}

impl fmt::Display for Stats {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    writeln!(f, "Compilation statistics:")?;
    for (key, value) in self.0.clone() {
      writeln!(f, "  {key}: {value}")?;
    }

    Ok(())
  }
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct AssetText {
  pub specifier: String,
  pub text: String,
}

/// Retrieve a static asset that are included in the binary.
fn get_lazily_loaded_asset(asset: &str) -> Option<&'static str> {
  LAZILY_LOADED_STATIC_ASSETS.get(asset).map(|s| s.to_owned())
}

fn get_maybe_hash(
  maybe_source: Option<&str>,
  hash_data: &[Vec<u8>],
) -> Option<String> {
  if let Some(source) = maybe_source {
    let mut data = vec![source.as_bytes().to_owned()];
    data.extend_from_slice(hash_data);
    Some(checksum::gen(&data))
  } else {
    None
  }
}

/// Hash the URL so it can be sent to `tsc` in a supportable way
fn hash_url(specifier: &ModuleSpecifier, media_type: MediaType) -> String {
  let hash = checksum::gen(&[specifier.path().as_bytes()]);
  format!(
    "{}:///{}{}",
    specifier.scheme(),
    hash,
    media_type.as_ts_extension()
  )
}

/// If the provided URLs derivable tsc media type doesn't match the media type,
/// we will add an extension to the output.  This is to avoid issues with
/// specifiers that don't have extensions, that tsc refuses to emit because they
/// think a `.js` version exists, when it doesn't.
fn maybe_remap_specifier(
  specifier: &ModuleSpecifier,
  media_type: MediaType,
) -> Option<String> {
  let path = if specifier.scheme() == "file" {
    if let Ok(path) = specifier.to_file_path() {
      path
    } else {
      PathBuf::from(specifier.path())
    }
  } else {
    PathBuf::from(specifier.path())
  };
  if path.extension().is_none() {
    Some(format!("{}{}", specifier, media_type.as_ts_extension()))
  } else {
    None
  }
}

/// tsc only supports `.ts`, `.tsx`, `.d.ts`, `.js`, or `.jsx` as root modules
/// and so we have to detect the apparent media type based on extensions it
/// supports.
fn get_tsc_media_type(specifier: &ModuleSpecifier) -> MediaType {
  let path = if specifier.scheme() == "file" {
    if let Ok(path) = specifier.to_file_path() {
      path
    } else {
      PathBuf::from(specifier.path())
    }
  } else {
    PathBuf::from(specifier.path())
  };
  match path.extension() {
    None => MediaType::Unknown,
    Some(os_str) => match os_str.to_str() {
      Some("ts") => {
        if let Some(os_str) = path.file_stem() {
          if let Some(file_name) = os_str.to_str() {
            if file_name.ends_with(".d") {
              return MediaType::Dts;
            }
          }
        }
        MediaType::TypeScript
      }
      Some("mts") => {
        if let Some(os_str) = path.file_stem() {
          if let Some(file_name) = os_str.to_str() {
            if file_name.ends_with(".d") {
              return MediaType::Dmts;
            }
          }
        }
        MediaType::Mts
      }
      Some("cts") => {
        if let Some(os_str) = path.file_stem() {
          if let Some(file_name) = os_str.to_str() {
            if file_name.ends_with(".d") {
              return MediaType::Dcts;
            }
          }
        }
        MediaType::Cts
      }
      Some("tsx") => MediaType::Tsx,
      Some("js") => MediaType::JavaScript,
      Some("mjs") => MediaType::Mjs,
      Some("cjs") => MediaType::Cjs,
      Some("jsx") => MediaType::Jsx,
      _ => MediaType::Unknown,
    },
  }
}

#[derive(Debug, Clone, Default, Eq, PartialEq)]
pub struct EmittedFile {
  pub data: String,
  pub maybe_specifiers: Option<Vec<ModuleSpecifier>>,
  pub media_type: MediaType,
}

/// A structure representing a request to be sent to the tsc runtime.
#[derive(Debug)]
pub struct Request {
  /// The TypeScript compiler options which will be serialized and sent to
  /// tsc.
  pub config: TsConfig,
  /// Indicates to the tsc runtime if debug logging should occur.
  pub debug: bool,
  pub graph: Arc<ModuleGraph>,
  pub hash_data: Vec<Vec<u8>>,
  pub maybe_config_specifier: Option<ModuleSpecifier>,
  pub maybe_npm_resolver: Option<NpmPackageResolver>,
  pub maybe_tsbuildinfo: Option<String>,
  /// A vector of strings that represent the root/entry point modules for the
  /// program.
  pub root_names: Vec<(ModuleSpecifier, MediaType)>,
}

#[derive(Debug, Clone, Eq, PartialEq)]
pub struct Response {
  /// Any diagnostics that have been returned from the checker.
  pub diagnostics: Diagnostics,
  /// If there was any build info associated with the exec request.
  pub maybe_tsbuildinfo: Option<String>,
  /// Statistics from the check.
  pub stats: Stats,
}

#[derive(Debug, Default)]
struct State {
  hash_data: Vec<Vec<u8>>,
  graph: Arc<ModuleGraph>,
  maybe_config_specifier: Option<ModuleSpecifier>,
  maybe_tsbuildinfo: Option<String>,
  maybe_response: Option<RespondArgs>,
  maybe_npm_resolver: Option<NpmPackageResolver>,
  remapped_specifiers: HashMap<String, ModuleSpecifier>,
  root_map: HashMap<String, ModuleSpecifier>,
}

impl State {
  pub fn new(
    graph: Arc<ModuleGraph>,
    hash_data: Vec<Vec<u8>>,
    maybe_config_specifier: Option<ModuleSpecifier>,
    maybe_npm_resolver: Option<NpmPackageResolver>,
    maybe_tsbuildinfo: Option<String>,
    root_map: HashMap<String, ModuleSpecifier>,
    remapped_specifiers: HashMap<String, ModuleSpecifier>,
  ) -> Self {
    State {
      hash_data,
      graph,
      maybe_config_specifier,
      maybe_npm_resolver,
      maybe_tsbuildinfo,
      maybe_response: None,
      remapped_specifiers,
      root_map,
    }
  }
}

fn normalize_specifier(specifier: &str) -> Result<ModuleSpecifier, AnyError> {
  resolve_url_or_path(&specifier.replace(".d.ts.d.ts", ".d.ts"))
    .map_err(|err| err.into())
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
struct CreateHashArgs {
  /// The string data to be used to generate the hash.  This will be mixed with
  /// other state data in Deno to derive the final hash.
  data: String,
}

#[op]
fn op_create_hash(s: &mut OpState, args: Value) -> Result<Value, AnyError> {
  let state = s.borrow_mut::<State>();
  let v: CreateHashArgs = serde_json::from_value(args)
    .context("Invalid request from JavaScript for \"op_create_hash\".")?;
  let mut data = vec![v.data.as_bytes().to_owned()];
  data.extend_from_slice(&state.hash_data);
  let hash = checksum::gen(&data);
  Ok(json!({ "hash": hash }))
}

#[op]
fn op_cwd(s: &mut OpState) -> Result<String, AnyError> {
  let state = s.borrow_mut::<State>();
  if let Some(config_specifier) = &state.maybe_config_specifier {
    let cwd = config_specifier.join("./")?;
    Ok(cwd.to_string())
  } else {
    Ok("cache:///".to_string())
  }
}

#[derive(Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
struct EmitArgs {
  /// The text data/contents of the file.
  data: String,
  /// The _internal_ filename for the file.  This will be used to determine how
  /// the file is cached and stored.
  file_name: String,
}

#[op]
fn op_emit(state: &mut OpState, args: EmitArgs) -> bool {
  let state = state.borrow_mut::<State>();
  match args.file_name.as_ref() {
    "internal:///.tsbuildinfo" => state.maybe_tsbuildinfo = Some(args.data),
    _ => {
      if cfg!(debug_assertions) {
        panic!("Unhandled emit write: {}", args.file_name);
      }
    }
  }

  true
}

#[derive(Debug, Deserialize)]
struct ExistsArgs {
  /// The fully qualified specifier that should be loaded.
  specifier: String,
}

#[op]
fn op_exists(state: &mut OpState, args: ExistsArgs) -> bool {
  let state = state.borrow_mut::<State>();
  let graph = &state.graph;
  if let Ok(specifier) = normalize_specifier(&args.specifier) {
    if specifier.scheme() == "asset" || specifier.scheme() == "data" {
      true
    } else {
      graph.get(&specifier).is_some()
    }
  } else {
    false
  }
}

#[derive(Debug, Deserialize)]
struct LoadArgs {
  /// The fully qualified specifier that should be loaded.
  specifier: String,
}

pub fn as_ts_script_kind(media_type: MediaType) -> i32 {
  match media_type {
    MediaType::JavaScript => 1,
    MediaType::Jsx => 2,
    MediaType::Mjs => 1,
    MediaType::Cjs => 1,
    MediaType::TypeScript => 3,
    MediaType::Mts => 3,
    MediaType::Cts => 3,
    MediaType::Dts => 3,
    MediaType::Dmts => 3,
    MediaType::Dcts => 3,
    MediaType::Tsx => 4,
    MediaType::Json => 6,
    MediaType::SourceMap
    | MediaType::TsBuildInfo
    | MediaType::Wasm
    | MediaType::Unknown => 0,
  }
}

#[op]
fn op_load(state: &mut OpState, args: Value) -> Result<Value, AnyError> {
  let state = state.borrow_mut::<State>();
  let v: LoadArgs = serde_json::from_value(args)
    .context("Invalid request from JavaScript for \"op_load\".")?;
  let specifier = normalize_specifier(&v.specifier)
    .context("Error converting a string module specifier for \"op_load\".")?;
  let mut hash: Option<String> = None;
  let mut media_type = MediaType::Unknown;
  let graph = &state.graph;
  let data = if &v.specifier == "internal:///.tsbuildinfo" {
    state.maybe_tsbuildinfo.as_deref().map(Cow::Borrowed)
  // in certain situations we return a "blank" module to tsc and we need to
  // handle the request for that module here.
  } else if &v.specifier == "internal:///missing_dependency.d.ts" {
    hash = Some("1".to_string());
    media_type = MediaType::Dts;
    Some(Cow::Borrowed("declare const __: any;\nexport = __;\n"))
  } else if let Some(name) = v.specifier.strip_prefix("asset:///") {
    let maybe_source = get_lazily_loaded_asset(name);
    hash = get_maybe_hash(maybe_source, &state.hash_data);
    media_type = MediaType::from(&v.specifier);
    maybe_source.map(Cow::Borrowed)
  } else {
    let specifier = if let Some(remapped_specifier) =
      state.remapped_specifiers.get(&v.specifier)
    {
      remapped_specifier
    } else if let Some(remapped_specifier) = state.root_map.get(&v.specifier) {
      remapped_specifier
    } else {
      &specifier
    };
    let maybe_source = if let Some(module) = graph.get(specifier) {
      match module {
        Module::Esm(module) => {
          media_type = module.media_type;
          Some(Cow::Borrowed(&*module.source))
        }
        Module::Json(module) => {
          media_type = MediaType::Json;
          Some(Cow::Borrowed(&*module.source))
        }
        Module::Npm(_) | Module::Node(_) => None,
        Module::External(module) => {
          // means it's Deno code importing an npm module
          let specifier =
            node::resolve_specifier_into_node_modules(&module.specifier);
          media_type = MediaType::from(&specifier);
          let file_path = specifier.to_file_path().unwrap();
          let code =
            std::fs::read_to_string(&file_path).with_context(|| {
              format!("Unable to load {}", file_path.display())
            })?;
          Some(Cow::Owned(code))
        }
      }
    } else if state
      .maybe_npm_resolver
      .as_ref()
      .map(|resolver| resolver.in_npm_package(specifier))
      .unwrap_or(false)
    {
      media_type = MediaType::from(specifier);
      let file_path = specifier.to_file_path().unwrap();
      let code = std::fs::read_to_string(&file_path)
        .with_context(|| format!("Unable to load {}", file_path.display()))?;
      Some(Cow::Owned(code))
    } else {
      media_type = MediaType::Unknown;
      None
    };
    hash = get_maybe_hash(maybe_source.as_deref(), &state.hash_data);
    maybe_source
  };

  Ok(json!({
    "data": data,
    "version": hash,
    "scriptKind": as_ts_script_kind(media_type),
  }))
}

#[derive(Debug, Deserialize, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct ResolveArgs {
  /// The base specifier that the supplied specifier strings should be resolved
  /// relative to.
  pub base: String,
  /// A list of specifiers that should be resolved.
  pub specifiers: Vec<String>,
}

#[op]
fn op_resolve(
  state: &mut OpState,
  args: ResolveArgs,
) -> Result<Vec<(String, String)>, AnyError> {
  let state = state.borrow_mut::<State>();
  let mut resolved: Vec<(String, String)> =
    Vec::with_capacity(args.specifiers.len());
  let referrer = if let Some(remapped_specifier) =
    state.remapped_specifiers.get(&args.base)
  {
    remapped_specifier.clone()
  } else if let Some(remapped_base) = state.root_map.get(&args.base) {
    remapped_base.clone()
  } else {
    normalize_specifier(&args.base).context(
      "Error converting a string module specifier for \"op_resolve\".",
    )?
  };
  for specifier in args.specifiers {
    if let Some(module_name) = specifier.strip_prefix("node:") {
      if crate::node::resolve_builtin_node_module(module_name).is_ok() {
        // return itself for node: specifiers because during type checking
        // we resolve to the ambient modules in the @types/node package
        // rather than deno_std/node
        resolved.push((specifier, MediaType::Dts.to_string()));
        continue;
      }
    }

    if specifier.starts_with("asset:///") {
      let media_type =
        MediaType::from(&specifier).as_ts_extension().to_string();
      resolved.push((specifier, media_type));
      continue;
    }

    let graph = &state.graph;
    let resolved_dep = graph
      .get(&referrer)
      .and_then(|m| m.esm())
      .and_then(|m| m.dependencies.get(&specifier))
      .and_then(|d| d.maybe_type.ok().or_else(|| d.maybe_code.ok()));

    let maybe_result = match resolved_dep {
      Some(ResolutionResolved { specifier, .. }) => {
        resolve_graph_specifier_types(specifier, state)?
      }
      _ => resolve_non_graph_specifier_types(&specifier, &referrer, state)?,
    };
    let result = match maybe_result {
      Some((specifier, media_type)) => {
        let specifier_str = match specifier.scheme() {
          "data" | "blob" => {
            let specifier_str = hash_url(&specifier, media_type);
            state
              .remapped_specifiers
              .insert(specifier_str.clone(), specifier);
            specifier_str
          }
          _ => {
            if let Some(specifier_str) =
              maybe_remap_specifier(&specifier, media_type)
            {
              state
                .remapped_specifiers
                .insert(specifier_str.clone(), specifier);
              specifier_str
            } else {
              specifier.to_string()
            }
          }
        };
        (specifier_str, media_type.as_ts_extension().into())
      }
      None => (
        "internal:///missing_dependency.d.ts".to_string(),
        ".d.ts".to_string(),
      ),
    };
    log::debug!("Resolved {} to {:?}", specifier, result);
    resolved.push(result);
  }

  Ok(resolved)
}

fn resolve_graph_specifier_types(
  specifier: &ModuleSpecifier,
  state: &State,
) -> Result<Option<(ModuleSpecifier, MediaType)>, AnyError> {
  let graph = &state.graph;
  let maybe_module = graph.get(specifier);
  // follow the types reference directive, which may be pointing at an npm package
  let maybe_module = match maybe_module {
    Some(Module::Esm(module)) => {
      let maybe_types_dep = module
        .maybe_types_dependency
        .as_ref()
        .map(|d| &d.dependency);
      match maybe_types_dep.and_then(|d| d.maybe_specifier()) {
        Some(specifier) => graph.get(specifier),
        _ => maybe_module,
      }
    }
    maybe_module => maybe_module,
  };

  // now get the types from the resolved module
  match maybe_module {
    Some(Module::Esm(module)) => {
      Ok(Some((module.specifier.clone(), module.media_type)))
    }
    Some(Module::Json(module)) => {
      Ok(Some((module.specifier.clone(), module.media_type)))
    }
    Some(Module::Npm(module)) => {
      if let Some(npm_resolver) = &state.maybe_npm_resolver {
        resolve_npm_package_reference_types(&module.nv_reference, npm_resolver)
          .map(Some)
      } else {
        Ok(None)
      }
    }
    Some(Module::External(module)) => {
      // we currently only use "External" for when the module is in an npm package
      Ok(state.maybe_npm_resolver.as_ref().map(|npm_resolver| {
        let specifier =
          node::resolve_specifier_into_node_modules(&module.specifier);
        NodeResolution::into_specifier_and_media_type(
          node::url_to_node_resolution(specifier, npm_resolver).ok(),
        )
      }))
    }
    Some(Module::Node(_)) | None => Ok(None),
  }
}

fn resolve_non_graph_specifier_types(
  specifier: &str,
  referrer: &ModuleSpecifier,
  state: &State,
) -> Result<Option<(ModuleSpecifier, MediaType)>, AnyError> {
  let npm_resolver = match state.maybe_npm_resolver.as_ref() {
    Some(npm_resolver) => npm_resolver,
    None => return Ok(None), // we only support non-graph types for npm packages
  };
  if npm_resolver.in_npm_package(referrer) {
    // we're in an npm package, so use node resolution
    Ok(Some(NodeResolution::into_specifier_and_media_type(
      node::node_resolve(
        specifier,
        referrer,
        NodeResolutionMode::Types,
        npm_resolver,
        &mut PermissionsContainer::allow_all(),
      )
      .ok()
      .flatten(),
    )))
  } else if let Ok(npm_ref) = NpmPackageReqReference::from_str(specifier) {
    // todo(dsherret): add support for injecting this in the graph so
    // we don't need this special code here.
    // This could occur when resolving npm:@types/node when it is
    // injected and not part of the graph
    let node_id = npm_resolver
      .resolution()
      .resolve_pkg_id_from_pkg_req(&npm_ref.req)?;
    let npm_id_ref = NpmPackageNvReference {
      nv: node_id.nv,
      sub_path: npm_ref.sub_path,
    };
    resolve_npm_package_reference_types(&npm_id_ref, npm_resolver).map(Some)
  } else {
    Ok(None)
  }
}

pub fn resolve_npm_package_reference_types(
  npm_ref: &NpmPackageNvReference,
  npm_resolver: &NpmPackageResolver,
) -> Result<(ModuleSpecifier, MediaType), AnyError> {
  let maybe_resolution = node_resolve_npm_reference(
    npm_ref,
    NodeResolutionMode::Types,
    npm_resolver,
    &mut PermissionsContainer::allow_all(),
  )?;
  Ok(NodeResolution::into_specifier_and_media_type(
    maybe_resolution,
  ))
}

#[op]
fn op_is_node_file(state: &mut OpState, path: &str) -> bool {
  let state = state.borrow::<State>();
  match ModuleSpecifier::parse(path) {
    Ok(specifier) => state
      .maybe_npm_resolver
      .as_ref()
      .map(|r| r.in_npm_package(&specifier))
      .unwrap_or(false),
    Err(_) => false,
  }
}

#[derive(Debug, Deserialize, Eq, PartialEq)]
struct RespondArgs {
  pub diagnostics: Diagnostics,
  pub stats: Stats,
}

#[op]
fn op_respond(state: &mut OpState, args: Value) -> Result<Value, AnyError> {
  let state = state.borrow_mut::<State>();
  let v: RespondArgs = serde_json::from_value(args)
    .context("Error converting the result for \"op_respond\".")?;
  state.maybe_response = Some(v);
  Ok(json!(true))
}

/// Execute a request on the supplied snapshot, returning a response which
/// contains information, like any emitted files, diagnostics, statistics and
/// optionally an updated TypeScript build info.
pub fn exec(request: Request) -> Result<Response, AnyError> {
  // tsc cannot handle root specifiers that don't have one of the "acceptable"
  // extensions.  Therefore, we have to check the root modules against their
  // extensions and remap any that are unacceptable to tsc and add them to the
  // op state so when requested, we can remap to the original specifier.
  let mut root_map = HashMap::new();
  let mut remapped_specifiers = HashMap::new();
  let root_names: Vec<String> = request
    .root_names
    .iter()
    .map(|(s, mt)| match s.scheme() {
      "data" | "blob" => {
        let specifier_str = hash_url(s, *mt);
        remapped_specifiers.insert(specifier_str.clone(), s.clone());
        specifier_str
      }
      _ => {
        let ext_media_type = get_tsc_media_type(s);
        if *mt != ext_media_type {
          let new_specifier = format!("{}{}", s, mt.as_ts_extension());
          root_map.insert(new_specifier.clone(), s.clone());
          new_specifier
        } else {
          s.as_str().to_owned()
        }
      }
    })
    .collect();
  let mut runtime = JsRuntime::new(RuntimeOptions {
    startup_snapshot: Some(compiler_snapshot()),
    extensions: vec![Extension::builder("deno_cli_tsc")
      .ops(get_tsc_ops())
      .state(move |state| {
        state.put(State::new(
          request.graph.clone(),
          request.hash_data.clone(),
          request.maybe_config_specifier.clone(),
          request.maybe_npm_resolver.clone(),
          request.maybe_tsbuildinfo.clone(),
          root_map.clone(),
          remapped_specifiers.clone(),
        ));
        Ok(())
      })
      .build()],
    ..Default::default()
  });

  let startup_source = "globalThis.startup({ legacyFlag: false })";
  let request_value = json!({
    "config": request.config,
    "debug": request.debug,
    "rootNames": root_names,
  });
  let request_str = request_value.to_string();
  let exec_source = format!("globalThis.exec({request_str})");

  runtime
    .execute_script(&located_script_name!(), startup_source)
    .context("Could not properly start the compiler runtime.")?;
  runtime.execute_script(&located_script_name!(), &exec_source)?;

  let op_state = runtime.op_state();
  let mut op_state = op_state.borrow_mut();
  let state = op_state.take::<State>();

  if let Some(response) = state.maybe_response {
    let diagnostics = response.diagnostics;
    let maybe_tsbuildinfo = state.maybe_tsbuildinfo;
    let stats = response.stats;

    Ok(Response {
      diagnostics,
      maybe_tsbuildinfo,
      stats,
    })
  } else {
    Err(anyhow!("The response for the exec request was not set."))
  }
}

fn get_tsc_ops() -> Vec<deno_core::OpDecl> {
  vec![
    op_cwd::decl(),
    op_create_hash::decl(),
    op_emit::decl(),
    op_exists::decl(),
    op_is_node_file::decl(),
    op_load::decl(),
    op_resolve::decl(),
    op_respond::decl(),
  ]
}

#[cfg(test)]
mod tests {
  use super::Diagnostic;
  use super::DiagnosticCategory;
  use super::*;
  use crate::args::TsConfig;
  use deno_core::futures::future;
  use deno_core::OpState;
  use deno_graph::ModuleGraph;
  use std::fs;

  #[derive(Debug, Default)]
  pub struct MockLoader {
    pub fixtures: PathBuf,
  }

  impl deno_graph::source::Loader for MockLoader {
    fn load(
      &mut self,
      specifier: &ModuleSpecifier,
      _is_dynamic: bool,
    ) -> deno_graph::source::LoadFuture {
      let specifier_text = specifier
        .to_string()
        .replace(":///", "_")
        .replace("://", "_")
        .replace('/', "-");
      let source_path = self.fixtures.join(specifier_text);
      let response = fs::read_to_string(source_path)
        .map(|c| {
          Some(deno_graph::source::LoadResponse::Module {
            specifier: specifier.clone(),
            maybe_headers: None,
            content: c.into(),
          })
        })
        .map_err(|err| err.into());
      Box::pin(future::ready(response))
    }
  }

  async fn setup(
    maybe_specifier: Option<ModuleSpecifier>,
    maybe_hash_data: Option<Vec<Vec<u8>>>,
    maybe_tsbuildinfo: Option<String>,
  ) -> OpState {
    let specifier = maybe_specifier
      .unwrap_or_else(|| resolve_url_or_path("file:///main.ts").unwrap());
    let hash_data = maybe_hash_data.unwrap_or_else(|| vec![b"".to_vec()]);
    let fixtures = test_util::testdata_path().join("tsc2");
    let mut loader = MockLoader { fixtures };
    let mut graph = ModuleGraph::default();
    graph
      .build(vec![specifier], &mut loader, Default::default())
      .await;
    let state = State::new(
      Arc::new(graph),
      hash_data,
      None,
      None,
      maybe_tsbuildinfo,
      HashMap::new(),
      HashMap::new(),
    );
    let mut op_state = OpState::new(1);
    op_state.put(state);
    op_state
  }

  async fn test_exec(
    specifier: &ModuleSpecifier,
  ) -> Result<Response, AnyError> {
    let hash_data = vec![b"something".to_vec()];
    let fixtures = test_util::testdata_path().join("tsc2");
    let mut loader = MockLoader { fixtures };
    let mut graph = ModuleGraph::default();
    graph
      .build(vec![specifier.clone()], &mut loader, Default::default())
      .await;
    let config = TsConfig::new(json!({
      "allowJs": true,
      "checkJs": false,
      "esModuleInterop": true,
      "emitDecoratorMetadata": false,
      "incremental": true,
      "jsx": "react",
      "jsxFactory": "React.createElement",
      "jsxFragmentFactory": "React.Fragment",
      "lib": ["deno.window"],
      "module": "esnext",
      "noEmit": true,
      "outDir": "internal:///",
      "strict": true,
      "target": "esnext",
      "tsBuildInfoFile": "internal:///.tsbuildinfo",
    }));
    let request = Request {
      config,
      debug: false,
      graph: Arc::new(graph),
      hash_data,
      maybe_config_specifier: None,
      maybe_npm_resolver: None,
      maybe_tsbuildinfo: None,
      root_names: vec![(specifier.clone(), MediaType::TypeScript)],
    };
    exec(request)
  }

  #[test]
  fn test_compiler_snapshot() {
    let mut js_runtime = JsRuntime::new(RuntimeOptions {
      startup_snapshot: Some(compiler_snapshot()),
      ..Default::default()
    });
    js_runtime
      .execute_script(
        "<anon>",
        r#"
      if (!(startup)) {
          throw Error("bad");
        }
        console.log(`ts version: ${ts.version}`);
      "#,
      )
      .unwrap();
  }

  #[tokio::test]
  async fn test_create_hash() {
    let mut state = setup(None, Some(vec![b"something".to_vec()]), None).await;
    let actual = op_create_hash::call(
      &mut state,
      json!({ "data": "some sort of content" }),
    )
    .expect("could not invoke op");
    assert_eq!(
      actual,
      json!({"hash": "ae92df8f104748768838916857a1623b6a3c593110131b0a00f81ad9dac16511"})
    );
  }

  #[test]
  fn test_hash_url() {
    let specifier = deno_core::resolve_url(
      "data:application/javascript,console.log(\"Hello%20Deno\");",
    )
    .unwrap();
    assert_eq!(hash_url(&specifier, MediaType::JavaScript), "data:///d300ea0796bd72b08df10348e0b70514c021f2e45bfe59cec24e12e97cd79c58.js");
  }

  #[test]
  fn test_get_tsc_media_type() {
    let fixtures = vec![
      ("file:///a.ts", MediaType::TypeScript),
      ("file:///a.cts", MediaType::Cts),
      ("file:///a.mts", MediaType::Mts),
      ("file:///a.tsx", MediaType::Tsx),
      ("file:///a.d.ts", MediaType::Dts),
      ("file:///a.d.cts", MediaType::Dcts),
      ("file:///a.d.mts", MediaType::Dmts),
      ("file:///a.js", MediaType::JavaScript),
      ("file:///a.jsx", MediaType::Jsx),
      ("file:///a.cjs", MediaType::Cjs),
      ("file:///a.mjs", MediaType::Mjs),
      ("file:///a.json", MediaType::Unknown),
      ("file:///a.wasm", MediaType::Unknown),
      ("file:///a.js.map", MediaType::Unknown),
      ("file:///.tsbuildinfo", MediaType::Unknown),
    ];
    for (specifier, media_type) in fixtures {
      let specifier = resolve_url_or_path(specifier).unwrap();
      assert_eq!(get_tsc_media_type(&specifier), media_type);
    }
  }

  #[tokio::test]
  async fn test_emit_tsbuildinfo() {
    let mut state = setup(None, None, None).await;
    let actual = op_emit::call(
      &mut state,
      EmitArgs {
        data: "some file content".to_string(),
        file_name: "internal:///.tsbuildinfo".to_string(),
      },
    );
    assert!(actual);
    let state = state.borrow::<State>();
    assert_eq!(
      state.maybe_tsbuildinfo,
      Some("some file content".to_string())
    );
  }

  #[tokio::test]
  async fn test_load() {
    let mut state = setup(
      Some(resolve_url_or_path("https://deno.land/x/mod.ts").unwrap()),
      None,
      Some("some content".to_string()),
    )
    .await;
    let actual = op_load::call(
      &mut state,
      json!({ "specifier": "https://deno.land/x/mod.ts"}),
    )
    .expect("should have invoked op");
    assert_eq!(
      actual,
      json!({
        "data": "console.log(\"hello deno\");\n",
        "version": "149c777056afcc973d5fcbe11421b6d5ddc57b81786765302030d7fc893bf729",
        "scriptKind": 3,
      })
    );
  }

  #[derive(Debug, Deserialize)]
  #[serde(rename_all = "camelCase")]
  struct LoadResponse {
    data: String,
    version: Option<String>,
    script_kind: i64,
  }

  #[tokio::test]
  async fn test_load_asset() {
    let mut state = setup(
      Some(resolve_url_or_path("https://deno.land/x/mod.ts").unwrap()),
      None,
      Some("some content".to_string()),
    )
    .await;
    let value = op_load::call(
      &mut state,
      json!({ "specifier": "asset:///lib.dom.d.ts" }),
    )
    .expect("should have invoked op");
    let actual: LoadResponse =
      serde_json::from_value(value).expect("failed to deserialize");
    let expected = get_lazily_loaded_asset("lib.dom.d.ts").unwrap();
    assert_eq!(actual.data, expected);
    assert!(actual.version.is_some());
    assert_eq!(actual.script_kind, 3);
  }

  #[tokio::test]
  async fn test_load_tsbuildinfo() {
    let mut state = setup(
      Some(resolve_url_or_path("https://deno.land/x/mod.ts").unwrap()),
      None,
      Some("some content".to_string()),
    )
    .await;
    let actual = op_load::call(
      &mut state,
      json!({ "specifier": "internal:///.tsbuildinfo"}),
    )
    .expect("should have invoked op");
    assert_eq!(
      actual,
      json!({
        "data": "some content",
        "version": null,
        "scriptKind": 0,
      })
    );
  }

  #[tokio::test]
  async fn test_load_missing_specifier() {
    let mut state = setup(None, None, None).await;
    let actual = op_load::call(
      &mut state,
      json!({ "specifier": "https://deno.land/x/mod.ts"}),
    )
    .expect("should have invoked op");
    assert_eq!(
      actual,
      json!({
        "data": null,
        "version": null,
        "scriptKind": 0,
      })
    )
  }

  #[tokio::test]
  async fn test_resolve() {
    let mut state = setup(
      Some(resolve_url_or_path("https://deno.land/x/a.ts").unwrap()),
      None,
      None,
    )
    .await;
    let actual = op_resolve::call(
      &mut state,
      ResolveArgs {
        base: "https://deno.land/x/a.ts".to_string(),
        specifiers: vec!["./b.ts".to_string()],
      },
    )
    .expect("should have invoked op");
    assert_eq!(
      actual,
      vec![("https://deno.land/x/b.ts".into(), ".ts".into())]
    );
  }

  #[tokio::test]
  async fn test_resolve_empty() {
    let mut state = setup(
      Some(resolve_url_or_path("https://deno.land/x/a.ts").unwrap()),
      None,
      None,
    )
    .await;
    let actual = op_resolve::call(
      &mut state,
      ResolveArgs {
        base: "https://deno.land/x/a.ts".to_string(),
        specifiers: vec!["./bad.ts".to_string()],
      },
    )
    .expect("should have not errored");
    assert_eq!(
      actual,
      vec![("internal:///missing_dependency.d.ts".into(), ".d.ts".into())]
    );
  }

  #[tokio::test]
  async fn test_respond() {
    let mut state = setup(None, None, None).await;
    let actual = op_respond::call(
      &mut state,
      json!({
        "diagnostics": [
          {
            "messageText": "Unknown compiler option 'invalid'.",
            "category": 1,
            "code": 5023
          }
        ],
        "stats": [["a", 12]]
      }),
    )
    .expect("should have invoked op");
    assert_eq!(actual, json!(true));
    let state = state.borrow::<State>();
    assert_eq!(
      state.maybe_response,
      Some(RespondArgs {
        diagnostics: Diagnostics::new(vec![Diagnostic {
          category: DiagnosticCategory::Error,
          code: 5023,
          start: None,
          end: None,
          message_text: Some(
            "Unknown compiler option \'invalid\'.".to_string()
          ),
          message_chain: None,
          source: None,
          source_line: None,
          file_name: None,
          related_information: None,
        }]),
        stats: Stats(vec![("a".to_string(), 12)])
      })
    );
  }

  #[tokio::test]
  async fn test_exec_basic() {
    let specifier = resolve_url_or_path("https://deno.land/x/a.ts").unwrap();
    let actual = test_exec(&specifier)
      .await
      .expect("exec should not have errored");
    assert!(actual.diagnostics.is_empty());
    assert!(actual.maybe_tsbuildinfo.is_some());
    assert_eq!(actual.stats.0.len(), 12);
  }

  #[tokio::test]
  async fn test_exec_reexport_dts() {
    let specifier = resolve_url_or_path("file:///reexports.ts").unwrap();
    let actual = test_exec(&specifier)
      .await
      .expect("exec should not have errored");
    assert!(actual.diagnostics.is_empty());
    assert!(actual.maybe_tsbuildinfo.is_some());
    assert_eq!(actual.stats.0.len(), 12);
  }

  #[tokio::test]
  async fn fix_lib_ref() {
    let specifier = resolve_url_or_path("file:///libref.ts").unwrap();
    let actual = test_exec(&specifier)
      .await
      .expect("exec should not have errored");
    assert!(actual.diagnostics.is_empty());
  }
}