// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
use crate::colors;
use crate::diagnostics::Diagnostic;
use crate::diagnostics::DiagnosticItem;
use crate::disk_cache::DiskCache;
use crate::file_fetcher::SourceFile;
use crate::file_fetcher::SourceFileFetcher;
use crate::global_state::GlobalState;
use crate::import_map::ImportMap;
use crate::module_graph::ModuleGraphFile;
use crate::module_graph::ModuleGraphLoader;
use crate::msg;
use crate::op_error::OpError;
use crate::ops;
use crate::permissions::Permissions;
use crate::source_maps::SourceMapGetter;
use crate::startup_data;
use crate::state::State;
use crate::version;
use crate::web_worker::WebWorker;
use crate::worker::WorkerEvent;
use core::task::Context;
use deno_core::Buf;
use deno_core::ErrBox;
use deno_core::ModuleSpecifier;
use deno_core::StartupData;
use futures::future::Either;
use futures::future::Future;
use futures::future::FutureExt;
use log::info;
use regex::Regex;
use serde::Deserialize;
use serde::Serialize;
use serde_json::json;
use serde_json::Value;
use sourcemap::SourceMap;
use std::collections::HashMap;
use std::collections::HashSet;
use std::fs;
use std::hash::BuildHasher;
use std::io;
use std::ops::Deref;
use std::ops::DerefMut;
use std::path::PathBuf;
use std::pin::Pin;
use std::str;
use std::sync::atomic::Ordering;
use std::sync::Arc;
use std::sync::Mutex;
use std::task::Poll;
use url::Url;

pub const AVAILABLE_LIBS: &[&str] = &[
  "deno.ns",
  "deno.window",
  "deno.worker",
  "deno.shared_globals",
  "deno.unstable",
  "dom",
  "dom.iterable",
  "es5",
  "es6",
  "esnext",
  "es2020",
  "es2020.full",
  "es2019",
  "es2019.full",
  "es2018",
  "es2018.full",
  "es2017",
  "es2017.full",
  "es2016",
  "es2016.full",
  "es2015",
  "es2015.collection",
  "es2015.core",
  "es2015.generator",
  "es2015.iterable",
  "es2015.promise",
  "es2015.proxy",
  "es2015.reflect",
  "es2015.symbol",
  "es2015.symbol.wellknown",
  "es2016.array.include",
  "es2017.intl",
  "es2017.object",
  "es2017.sharedmemory",
  "es2017.string",
  "es2017.typedarrays",
  "es2018.asyncgenerator",
  "es2018.asynciterable",
  "es2018.intl",
  "es2018.promise",
  "es2018.regexp",
  "es2019.array",
  "es2019.object",
  "es2019.string",
  "es2019.symbol",
  "es2020.bigint",
  "es2020.promise",
  "es2020.string",
  "es2020.symbol.wellknown",
  "esnext.array",
  "esnext.asynciterable",
  "esnext.bigint",
  "esnext.intl",
  "esnext.promise",
  "esnext.string",
  "esnext.symbol",
  "scripthost",
  "webworker",
  "webworker.importscripts",
];

#[derive(Debug, Clone)]
pub struct CompiledModule {
  pub code: String,
  pub name: String,
}

pub struct CompilerWorker(WebWorker);

impl CompilerWorker {
  pub fn new(name: String, startup_data: StartupData, state: State) -> Self {
    let state_ = state.clone();
    let mut worker = WebWorker::new(name, startup_data, state_, false);
    {
      let isolate = &mut worker.isolate;
      ops::compiler::init(isolate, &state);
    }
    Self(worker)
  }
}

impl Deref for CompilerWorker {
  type Target = WebWorker;
  fn deref(&self) -> &Self::Target {
    &self.0
  }
}

impl DerefMut for CompilerWorker {
  fn deref_mut(&mut self) -> &mut Self::Target {
    &mut self.0
  }
}

impl Future for CompilerWorker {
  type Output = Result<(), ErrBox>;

  fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
    let inner = self.get_mut();
    inner.0.poll_unpin(cx)
  }
}

// TODO(bartlomieju): use JSONC parser from dprint instead of Regex
lazy_static! {
  static ref CHECK_JS_RE: Regex =
    Regex::new(r#""checkJs"\s*?:\s*?true"#).unwrap();
}

/// Create a new worker with snapshot of TS compiler and setup compiler's
/// runtime.
fn create_compiler_worker(
  global_state: GlobalState,
  permissions: Permissions,
) -> CompilerWorker {
  // TODO(bartlomieju): these $deno$ specifiers should be unified for all subcommands
  // like 'eval', 'repl'
  let entry_point =
    ModuleSpecifier::resolve_url_or_path("./__$deno$ts_compiler.ts").unwrap();
  let worker_state = State::new(
    global_state.clone(),
    Some(permissions),
    entry_point,
    None,
    true,
  )
  .expect("Unable to create worker state");

  // TODO(bartlomieju): this metric is never used anywhere
  // Count how many times we start the compiler worker.
  global_state.compiler_starts.fetch_add(1, Ordering::SeqCst);

  let mut worker = CompilerWorker::new(
    "TS".to_string(),
    startup_data::compiler_isolate_init(),
    worker_state,
  );
  worker.execute("bootstrap.tsCompilerRuntime()").unwrap();
  worker
}

#[derive(Clone)]
pub enum TargetLib {
  Main,
  Worker,
}

/// Struct which represents the state of the compiler
/// configuration where the first is canonical name for the configuration file,
/// second is a vector of the bytes of the contents of the configuration file,
/// third is bytes of the hash of contents.
#[derive(Clone)]
pub struct CompilerConfig {
  pub path: Option<PathBuf>,
  pub content: Option<Vec<u8>>,
  pub hash: Vec<u8>,
  pub compile_js: bool,
}

impl CompilerConfig {
  /// Take the passed flag and resolve the file name relative to the cwd.
  pub fn load(config_path: Option<String>) -> Result<Self, ErrBox> {
    let config_file = match &config_path {
      Some(config_file_name) => {
        debug!("Compiler config file: {}", config_file_name);
        let cwd = std::env::current_dir().unwrap();
        Some(cwd.join(config_file_name))
      }
      _ => None,
    };

    // Convert the PathBuf to a canonicalized string.  This is needed by the
    // compiler to properly deal with the configuration.
    let config_path = match &config_file {
      Some(config_file) => Some(config_file.canonicalize().map_err(|_| {
        io::Error::new(
          io::ErrorKind::InvalidInput,
          format!(
            "Could not find the config file: {}",
            config_file.to_string_lossy()
          ),
        )
      })),
      _ => None,
    };

    // Load the contents of the configuration file
    let config = match &config_file {
      Some(config_file) => {
        debug!("Attempt to load config: {}", config_file.to_str().unwrap());
        let config = fs::read(&config_file)?;
        Some(config)
      }
      _ => None,
    };

    let config_hash = match &config {
      Some(bytes) => bytes.clone(),
      _ => b"".to_vec(),
    };

    // If `checkJs` is set to true in `compilerOptions` then we're gonna be compiling
    // JavaScript files as well
    let compile_js = if let Some(config_content) = config.clone() {
      let config_str = std::str::from_utf8(&config_content)?;
      CHECK_JS_RE.is_match(config_str)
    } else {
      false
    };

    let ts_config = Self {
      path: config_path.unwrap_or_else(|| Ok(PathBuf::new())).ok(),
      content: config,
      hash: config_hash,
      compile_js,
    };

    Ok(ts_config)
  }
}

/// Information associated with compiled file in cache.
/// Includes source code path and state hash.
/// version_hash is used to validate versions of the file
/// and could be used to remove stale file in cache.
#[derive(Deserialize, Serialize)]
pub struct CompiledFileMetadata {
  pub source_path: PathBuf,
  pub version_hash: String,
}

impl CompiledFileMetadata {
  pub fn from_json_string(
    metadata_string: String,
  ) -> Result<Self, serde_json::Error> {
    serde_json::from_str::<Self>(&metadata_string)
  }

  pub fn to_json_string(&self) -> Result<String, serde_json::Error> {
    serde_json::to_string(self)
  }
}

/// Information associated with compilation of a "module graph",
/// ie. entry point and all its dependencies.
/// It's used to perform cache invalidation if content of any
/// dependency changes.
#[derive(Deserialize, Serialize)]
pub struct GraphFileMetadata {
  pub deps: Vec<String>,
  pub version_hash: String,
}

impl GraphFileMetadata {
  pub fn from_json_string(
    metadata_string: String,
  ) -> Result<Self, serde_json::Error> {
    serde_json::from_str::<Self>(&metadata_string)
  }

  pub fn to_json_string(&self) -> Result<String, serde_json::Error> {
    serde_json::to_string(self)
  }
}

/// Emit a SHA256 hash based on source code, deno version and TS config.
/// Used to check if a recompilation for source code is needed.
pub fn source_code_version_hash(
  source_code: &[u8],
  version: &str,
  config_hash: &[u8],
) -> String {
  crate::checksum::gen(vec![source_code, version.as_bytes(), config_hash])
}

pub struct TsCompilerInner {
  pub file_fetcher: SourceFileFetcher,
  pub config: CompilerConfig,
  pub disk_cache: DiskCache,
  /// Set of all URLs that have been compiled. This prevents double
  /// compilation of module.
  pub compiled: Mutex<HashSet<Url>>,
  /// This setting is controlled by `--reload` flag. Unless the flag
  /// is provided disk cache is used.
  pub use_disk_cache: bool,
  /// This setting is controlled by `compilerOptions.checkJs`
  pub compile_js: bool,
}

#[derive(Clone)]
pub struct TsCompiler(Arc<TsCompilerInner>);

impl Deref for TsCompiler {
  type Target = TsCompilerInner;
  fn deref(&self) -> &Self::Target {
    &self.0
  }
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct EmittedSource {
  filename: String,
  contents: String,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct BundleResponse {
  diagnostics: Diagnostic,
  bundle_output: Option<String>,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct CompileResponse {
  diagnostics: Diagnostic,
  emit_map: HashMap<String, EmittedSource>,
}

// TODO(bartlomieju): possible deduplicate once TS refactor is stabilized
#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
#[allow(unused)]
struct RuntimeBundleResponse {
  diagnostics: Vec<DiagnosticItem>,
  output: String,
}

#[derive(Deserialize)]
#[serde(rename_all = "camelCase")]
struct RuntimeCompileResponse {
  diagnostics: Vec<DiagnosticItem>,
  emit_map: HashMap<String, EmittedSource>,
}

impl TsCompiler {
  pub fn new(
    file_fetcher: SourceFileFetcher,
    disk_cache: DiskCache,
    use_disk_cache: bool,
    config_path: Option<String>,
  ) -> Result<Self, ErrBox> {
    let config = CompilerConfig::load(config_path)?;
    Ok(TsCompiler(Arc::new(TsCompilerInner {
      file_fetcher,
      disk_cache,
      compile_js: config.compile_js,
      config,
      compiled: Mutex::new(HashSet::new()),
      use_disk_cache,
    })))
  }

  // TODO(bartlomieju): this method is no longer needed
  /// Mark given module URL as compiled to avoid multiple compilations of same
  /// module in single run.
  fn mark_compiled(&self, url: &Url) {
    let mut c = self.compiled.lock().unwrap();
    c.insert(url.clone());
  }

  /// Check if there is compiled source in cache that is valid
  /// and can be used again.
  // TODO(bartlomieju): there should be check that cached file actually exists
  fn has_compiled_source(
    &self,
    file_fetcher: &SourceFileFetcher,
    url: &Url,
  ) -> bool {
    let specifier = ModuleSpecifier::from(url.clone());
    if let Some(source_file) = file_fetcher
      .fetch_cached_source_file(&specifier, Permissions::allow_all())
    {
      if let Some(metadata) = self.get_metadata(&url) {
        // 2. compare version hashes
        // TODO: it would probably be good idea to make it method implemented on SourceFile
        let version_hash_to_validate = source_code_version_hash(
          &source_file.source_code,
          version::DENO,
          &self.config.hash,
        );

        if metadata.version_hash == version_hash_to_validate {
          return true;
        }
      }
    }

    false
  }

  /// Asynchronously compile module and all it's dependencies.
  ///
  /// This method compiled every module at most once.
  ///
  /// If `--reload` flag was provided then compiler will not on-disk cache and
  /// force recompilation.
  ///
  /// If compilation is required then new V8 worker is spawned with fresh TS
  /// compiler.
  pub async fn compile_module_graph(
    &self,
    global_state: GlobalState,
    source_file: &SourceFile,
    target: TargetLib,
    permissions: Permissions,
    module_graph: HashMap<String, ModuleGraphFile>,
  ) -> Result<(), ErrBox> {
    let mut has_cached_version = false;

    if self.use_disk_cache {
      if let Some(metadata) = self.get_graph_metadata(&source_file.url) {
        has_cached_version = true;

        let version_hash = crate::checksum::gen(vec![
          version::DENO.as_bytes(),
          &self.config.hash,
        ]);

        has_cached_version &= metadata.version_hash == version_hash;
        has_cached_version &= self
          .has_compiled_source(&global_state.file_fetcher, &source_file.url);

        for dep in metadata.deps {
          let url = Url::parse(&dep).expect("Dep is not a valid url");
          has_cached_version &=
            self.has_compiled_source(&global_state.file_fetcher, &url);
        }
      }
    }

    if has_cached_version {
      return Ok(());
    }

    let module_url = source_file.url.clone();

    let module_graph_json =
      serde_json::to_value(module_graph).expect("Failed to serialize data");
    let target = match target {
      TargetLib::Main => "main",
      TargetLib::Worker => "worker",
    };
    let root_names = vec![module_url.to_string()];
    let bundle = false;
    let unstable = global_state.flags.unstable;
    let compiler_config = self.config.clone();
    let cwd = std::env::current_dir().unwrap();
    let j = match (compiler_config.path, compiler_config.content) {
      (Some(config_path), Some(config_data)) => json!({
        "type": msg::CompilerRequestType::Compile as i32,
        "target": target,
        "rootNames": root_names,
        "bundle": bundle,
        "unstable": unstable,
        "configPath": config_path,
        "config": str::from_utf8(&config_data).unwrap(),
        "cwd": cwd,
        "sourceFileMap": module_graph_json,
      }),
      _ => json!({
        "type": msg::CompilerRequestType::Compile as i32,
        "target": target,
        "rootNames": root_names,
        "bundle": bundle,
        "unstable": unstable,
        "cwd": cwd,
        "sourceFileMap": module_graph_json,
      }),
    };

    let req_msg = j.to_string().into_boxed_str().into_boxed_bytes();

    // TODO(bartlomieju): lift this call up - TSC shouldn't print anything
    info!(
      "{} {}",
      colors::green("Compile".to_string()),
      module_url.to_string()
    );

    let msg =
      execute_in_same_thread(global_state.clone(), permissions, req_msg)
        .await?;

    let json_str = std::str::from_utf8(&msg).unwrap();

    let compile_response: CompileResponse = serde_json::from_str(json_str)?;

    if !compile_response.diagnostics.items.is_empty() {
      return Err(ErrBox::from(compile_response.diagnostics));
    }

    self.set_graph_metadata(
      source_file.url.clone(),
      &compile_response.emit_map,
    )?;
    self.cache_emitted_files(compile_response.emit_map)?;
    Ok(())
  }

  fn get_graph_metadata(&self, url: &Url) -> Option<GraphFileMetadata> {
    // Try to load cached version:
    // 1. check if there's 'meta' file
    let cache_key = self
      .disk_cache
      .get_cache_filename_with_extension(url, "graph");
    if let Ok(metadata_bytes) = self.disk_cache.get(&cache_key) {
      if let Ok(metadata) = std::str::from_utf8(&metadata_bytes) {
        if let Ok(read_metadata) =
          GraphFileMetadata::from_json_string(metadata.to_string())
        {
          return Some(read_metadata);
        }
      }
    }

    None
  }

  fn set_graph_metadata(
    &self,
    url: Url,
    emit_map: &HashMap<String, EmittedSource>,
  ) -> std::io::Result<()> {
    let version_hash =
      crate::checksum::gen(vec![version::DENO.as_bytes(), &self.config.hash]);
    let mut deps = vec![];

    for (_emitted_name, source) in emit_map.iter() {
      let specifier = ModuleSpecifier::resolve_url(&source.filename)
        .expect("Should be a valid module specifier");

      let source_file = self
        .file_fetcher
        .fetch_cached_source_file(&specifier, Permissions::allow_all())
        .expect("Source file not found");

      // NOTE: JavaScript files are only cached to disk if `checkJs`
      // option in on
      if source_file.media_type == msg::MediaType::JavaScript
        && !self.compile_js
      {
        continue;
      }

      deps.push(specifier.to_string());
    }

    let graph_metadata = GraphFileMetadata { deps, version_hash };
    let meta_key = self
      .disk_cache
      .get_cache_filename_with_extension(&url, "graph");
    self
      .disk_cache
      .set(&meta_key, graph_metadata.to_json_string()?.as_bytes())
  }

  /// Get associated `CompiledFileMetadata` for given module if it exists.
  pub fn get_metadata(&self, url: &Url) -> Option<CompiledFileMetadata> {
    // Try to load cached version:
    // 1. check if there's 'meta' file
    let cache_key = self
      .disk_cache
      .get_cache_filename_with_extension(url, "meta");
    if let Ok(metadata_bytes) = self.disk_cache.get(&cache_key) {
      if let Ok(metadata) = std::str::from_utf8(&metadata_bytes) {
        if let Ok(read_metadata) =
          CompiledFileMetadata::from_json_string(metadata.to_string())
        {
          return Some(read_metadata);
        }
      }
    }

    None
  }

  fn cache_emitted_files(
    &self,
    emit_map: HashMap<String, EmittedSource>,
  ) -> std::io::Result<()> {
    for (emitted_name, source) in emit_map.iter() {
      let specifier = ModuleSpecifier::resolve_url(&source.filename)
        .expect("Should be a valid module specifier");

      let source_file = self
        .file_fetcher
        .fetch_cached_source_file(&specifier, Permissions::allow_all())
        .expect("Source file not found");

      // NOTE: JavaScript files are only cached to disk if `checkJs`
      // option in on
      if source_file.media_type == msg::MediaType::JavaScript
        && !self.compile_js
      {
        continue;
      }

      if emitted_name.ends_with(".map") {
        self.cache_source_map(&specifier, &source.contents)?;
      } else if emitted_name.ends_with(".js") {
        self.cache_compiled_file(&specifier, source_file, &source.contents)?;
      } else {
        panic!("Trying to cache unknown file type {}", emitted_name);
      }
    }

    Ok(())
  }

  pub fn get_compiled_module(
    &self,
    module_url: &Url,
  ) -> Result<CompiledModule, ErrBox> {
    let compiled_source_file = self.get_compiled_source_file(module_url)?;

    let compiled_module = CompiledModule {
      code: str::from_utf8(&compiled_source_file.source_code)
        .unwrap()
        .to_string(),
      name: module_url.to_string(),
    };

    Ok(compiled_module)
  }

  /// Return compiled JS file for given TS module.
  // TODO: ideally we shouldn't construct SourceFile by hand, but it should be delegated to
  // SourceFileFetcher
  pub fn get_compiled_source_file(
    &self,
    module_url: &Url,
  ) -> Result<SourceFile, ErrBox> {
    let cache_key = self
      .disk_cache
      .get_cache_filename_with_extension(&module_url, "js");
    let compiled_code = self.disk_cache.get(&cache_key)?;
    let compiled_code_filename = self.disk_cache.location.join(cache_key);
    debug!("compiled filename: {:?}", compiled_code_filename);

    let compiled_module = SourceFile {
      url: module_url.clone(),
      filename: compiled_code_filename,
      media_type: msg::MediaType::JavaScript,
      source_code: compiled_code,
      types_url: None,
      types_header: None,
    };

    Ok(compiled_module)
  }

  /// Save compiled JS file for given TS module to on-disk cache.
  ///
  /// Along compiled file a special metadata file is saved as well containing
  /// hash that can be validated to avoid unnecessary recompilation.
  fn cache_compiled_file(
    &self,
    module_specifier: &ModuleSpecifier,
    source_file: SourceFile,
    contents: &str,
  ) -> std::io::Result<()> {
    // By default TSC output source map url that is relative; we need
    // to substitute it manually to correct file URL in DENO_DIR.
    let mut content_lines = contents
      .split('\n')
      .map(|s| s.to_string())
      .collect::<Vec<String>>();

    if !content_lines.is_empty() {
      let last_line = content_lines.pop().unwrap();
      if last_line.starts_with("//# sourceMappingURL=") {
        let source_map_key = self.disk_cache.get_cache_filename_with_extension(
          module_specifier.as_url(),
          "js.map",
        );
        let source_map_path = self.disk_cache.location.join(source_map_key);
        let source_map_file_url = Url::from_file_path(source_map_path)
          .expect("Bad file URL for source map");
        let new_last_line =
          format!("//# sourceMappingURL={}", source_map_file_url.to_string());
        content_lines.push(new_last_line);
      } else {
        content_lines.push(last_line);
      }
    }

    let contents = content_lines.join("\n");

    let js_key = self
      .disk_cache
      .get_cache_filename_with_extension(module_specifier.as_url(), "js");
    self.disk_cache.set(&js_key, contents.as_bytes())?;
    self.mark_compiled(module_specifier.as_url());

    let version_hash = source_code_version_hash(
      &source_file.source_code,
      version::DENO,
      &self.config.hash,
    );

    let compiled_file_metadata = CompiledFileMetadata {
      source_path: source_file.filename,
      version_hash,
    };
    let meta_key = self
      .disk_cache
      .get_cache_filename_with_extension(module_specifier.as_url(), "meta");
    self.disk_cache.set(
      &meta_key,
      compiled_file_metadata.to_json_string()?.as_bytes(),
    )
  }

  /// Return associated source map file for given TS module.
  // TODO: ideally we shouldn't construct SourceFile by hand, but it should be delegated to
  // SourceFileFetcher
  pub fn get_source_map_file(
    &self,
    module_specifier: &ModuleSpecifier,
  ) -> Result<SourceFile, ErrBox> {
    let cache_key = self
      .disk_cache
      .get_cache_filename_with_extension(module_specifier.as_url(), "js.map");
    let source_code = self.disk_cache.get(&cache_key)?;
    let source_map_filename = self.disk_cache.location.join(cache_key);
    debug!("source map filename: {:?}", source_map_filename);

    let source_map_file = SourceFile {
      url: module_specifier.as_url().to_owned(),
      filename: source_map_filename,
      media_type: msg::MediaType::JavaScript,
      source_code,
      types_url: None,
      types_header: None,
    };

    Ok(source_map_file)
  }

  /// Save source map file for given TS module to on-disk cache.
  fn cache_source_map(
    &self,
    module_specifier: &ModuleSpecifier,
    contents: &str,
  ) -> std::io::Result<()> {
    let js_key = self
      .disk_cache
      .get_cache_filename_with_extension(module_specifier.as_url(), "js");
    let js_path = self.disk_cache.location.join(js_key);
    let js_file_url =
      Url::from_file_path(js_path).expect("Bad file URL for file");

    let source_map_key = self
      .disk_cache
      .get_cache_filename_with_extension(module_specifier.as_url(), "js.map");

    let mut sm = SourceMap::from_slice(contents.as_bytes())
      .expect("Invalid source map content");
    sm.set_file(Some(&js_file_url.to_string()));
    sm.set_source(0, &module_specifier.to_string());

    let mut output: Vec<u8> = vec![];
    sm.to_writer(&mut output)
      .expect("Failed to write source map");

    self.disk_cache.set(&source_map_key, &output)
  }
}

impl SourceMapGetter for TsCompiler {
  fn get_source_map(&self, script_name: &str) -> Option<Vec<u8>> {
    self
      .try_to_resolve_and_get_source_map(script_name)
      .map(|out| out.source_code)
  }

  fn get_source_line(&self, script_name: &str, line: usize) -> Option<String> {
    self
      .try_resolve_and_get_source_file(script_name)
      .and_then(|out| {
        str::from_utf8(&out.source_code).ok().map(|v| {
          // Do NOT use .lines(): it skips the terminating empty line.
          // (due to internally using .split_terminator() instead of .split())
          let lines: Vec<&str> = v.split('\n').collect();
          assert!(lines.len() > line);
          lines[line].to_string()
        })
      })
  }
}

// `SourceMapGetter` related methods
impl TsCompiler {
  fn try_to_resolve(&self, script_name: &str) -> Option<ModuleSpecifier> {
    // if `script_name` can't be resolved to ModuleSpecifier it's probably internal
    // script (like `gen/cli/bundle/compiler.js`) so we won't be
    // able to get source for it anyway
    ModuleSpecifier::resolve_url(script_name).ok()
  }

  fn try_resolve_and_get_source_file(
    &self,
    script_name: &str,
  ) -> Option<SourceFile> {
    if let Some(module_specifier) = self.try_to_resolve(script_name) {
      return self
        .file_fetcher
        .fetch_cached_source_file(&module_specifier, Permissions::allow_all());
    }

    None
  }

  fn try_to_resolve_and_get_source_map(
    &self,
    script_name: &str,
  ) -> Option<SourceFile> {
    if let Some(module_specifier) = self.try_to_resolve(script_name) {
      return match self.get_source_map_file(&module_specifier) {
        Ok(out) => Some(out),
        Err(_) => None,
      };
    }

    None
  }
}

async fn execute_in_same_thread(
  global_state: GlobalState,
  permissions: Permissions,
  req: Buf,
) -> Result<Buf, ErrBox> {
  let mut worker = create_compiler_worker(global_state.clone(), permissions);
  let handle = worker.thread_safe_handle();
  handle.post_message(req)?;

  let mut event_fut = handle.get_event().boxed_local();

  loop {
    let select_result = futures::future::select(event_fut, &mut worker).await;
    match select_result {
      Either::Left((event_result, _worker)) => {
        let event = event_result
          .expect("Compiler didn't respond")
          .expect("Empty message");

        let buf = match event {
          WorkerEvent::Message(buf) => Ok(buf),
          WorkerEvent::Error(error) => Err(error),
          WorkerEvent::TerminalError(error) => Err(error),
        }?;
        return Ok(buf);
      }
      Either::Right((worker_result, event_fut_)) => {
        event_fut = event_fut_;
        worker_result?;
      }
    }
  }
}

pub async fn bundle(
  global_state: &GlobalState,
  compiler_config: CompilerConfig,
  module_specifier: ModuleSpecifier,
  maybe_import_map: Option<ImportMap>,
  unstable: bool,
) -> Result<String, ErrBox> {
  debug!(
    "Invoking the compiler to bundle. module_name: {}",
    module_specifier.to_string()
  );

  let permissions = Permissions::allow_all();
  let mut module_graph_loader = ModuleGraphLoader::new(
    global_state.file_fetcher.clone(),
    maybe_import_map,
    permissions.clone(),
    false,
    true,
  );
  module_graph_loader
    .add_to_graph(&module_specifier, None)
    .await?;
  let module_graph = module_graph_loader.get_graph();
  let module_graph_json =
    serde_json::to_value(module_graph).expect("Failed to serialize data");

  let root_names = vec![module_specifier.to_string()];
  let bundle = true;
  let target = "main";
  let cwd = std::env::current_dir().unwrap();

  // TODO(bartlomieju): this is non-sense; CompilerConfig's `path` and `content` should
  // be optional
  let j = match (compiler_config.path, compiler_config.content) {
    (Some(config_path), Some(config_data)) => json!({
      "type": msg::CompilerRequestType::Compile as i32,
      "target": target,
      "rootNames": root_names,
      "bundle": bundle,
      "unstable": unstable,
      "configPath": config_path,
      "config": str::from_utf8(&config_data).unwrap(),
      "cwd": cwd,
      "sourceFileMap": module_graph_json,
    }),
    _ => json!({
      "type": msg::CompilerRequestType::Compile as i32,
      "target": target,
      "rootNames": root_names,
      "bundle": bundle,
      "unstable": unstable,
      "cwd": cwd,
      "sourceFileMap": module_graph_json,
    }),
  };

  let req_msg = j.to_string().into_boxed_str().into_boxed_bytes();

  let msg =
    execute_in_same_thread(global_state.clone(), permissions, req_msg).await?;
  let json_str = std::str::from_utf8(&msg).unwrap();
  debug!("Message: {}", json_str);

  let bundle_response: BundleResponse = serde_json::from_str(json_str)?;

  if !bundle_response.diagnostics.items.is_empty() {
    return Err(ErrBox::from(bundle_response.diagnostics));
  }

  assert!(bundle_response.bundle_output.is_some());
  let output = bundle_response.bundle_output.unwrap();
  Ok(output)
}

/// This function is used by `Deno.compile()` and `Deno.bundle()` APIs.
pub async fn runtime_compile<S: BuildHasher>(
  global_state: GlobalState,
  permissions: Permissions,
  root_name: &str,
  sources: &Option<HashMap<String, String, S>>,
  bundle: bool,
  maybe_options: &Option<String>,
) -> Result<Value, OpError> {
  let mut root_names = vec![];
  let mut module_graph_loader = ModuleGraphLoader::new(
    global_state.file_fetcher.clone(),
    None,
    permissions.clone(),
    false,
    false,
  );

  if let Some(s_map) = sources {
    root_names.push(root_name.to_string());
    module_graph_loader.build_local_graph(root_name, s_map)?;
  } else {
    let module_specifier =
      ModuleSpecifier::resolve_import(root_name, "<unknown>")?;
    root_names.push(module_specifier.to_string());
    module_graph_loader
      .add_to_graph(&module_specifier, None)
      .await?;
  }

  // download all additional files from TSconfig and add them to root_names
  if let Some(options) = maybe_options {
    let options_json: serde_json::Value = serde_json::from_str(options)?;
    if let Some(types_option) = options_json.get("types") {
      let types_arr = types_option.as_array().expect("types is not an array");

      for type_value in types_arr {
        let type_str = type_value
          .as_str()
          .expect("type is not a string")
          .to_string();
        let type_specifier = ModuleSpecifier::resolve_url_or_path(&type_str)?;
        module_graph_loader
          .add_to_graph(&type_specifier, None)
          .await?;
        root_names.push(type_specifier.to_string())
      }
    }
  }

  let module_graph = module_graph_loader.get_graph();
  let module_graph_json =
    serde_json::to_value(module_graph).expect("Failed to serialize data");

  let req_msg = json!({
    "type": msg::CompilerRequestType::RuntimeCompile as i32,
    "target": "runtime",
    "rootNames": root_names,
    "sourceFileMap": module_graph_json,
    "options": maybe_options,
    "bundle": bundle,
    "unstable": global_state.flags.unstable,
  })
  .to_string()
  .into_boxed_str()
  .into_boxed_bytes();

  let compiler = global_state.ts_compiler.clone();

  let msg = execute_in_same_thread(global_state, permissions, req_msg).await?;
  let json_str = std::str::from_utf8(&msg).unwrap();

  // TODO(bartlomieju): factor `bundle` path into separate function `runtime_bundle`
  if bundle {
    let _response: RuntimeBundleResponse = serde_json::from_str(json_str)?;
    return Ok(serde_json::from_str::<Value>(json_str).unwrap());
  }

  let response: RuntimeCompileResponse = serde_json::from_str(json_str)?;

  if response.diagnostics.is_empty() && sources.is_none() {
    compiler.cache_emitted_files(response.emit_map)?;
  }

  // We're returning `Ok()` instead of `Err()` because it's not runtime
  // error if there were diagnostics produces; we want to let user handle
  // diagnostics in the runtime.
  Ok(serde_json::from_str::<Value>(json_str).unwrap())
}

/// This function is used by `Deno.transpileOnly()` API.
pub async fn runtime_transpile<S: BuildHasher>(
  global_state: GlobalState,
  permissions: Permissions,
  sources: &HashMap<String, String, S>,
  options: &Option<String>,
) -> Result<Value, OpError> {
  let req_msg = json!({
    "type": msg::CompilerRequestType::RuntimeTranspile as i32,
    "sources": sources,
    "options": options,
  })
  .to_string()
  .into_boxed_str()
  .into_boxed_bytes();

  let msg = execute_in_same_thread(global_state, permissions, req_msg).await?;
  let json_str = std::str::from_utf8(&msg).unwrap();
  let v = serde_json::from_str::<serde_json::Value>(json_str)
    .expect("Error decoding JSON string.");
  Ok(v)
}

#[cfg(test)]
mod tests {
  use super::*;
  use crate::fs as deno_fs;
  use deno_core::ModuleSpecifier;
  use std::path::PathBuf;
  use tempfile::TempDir;

  #[tokio::test]
  async fn test_compile() {
    let p = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
      .parent()
      .unwrap()
      .join("cli/tests/002_hello.ts");
    let specifier =
      ModuleSpecifier::resolve_url_or_path(p.to_str().unwrap()).unwrap();
    let out = SourceFile {
      url: specifier.as_url().clone(),
      filename: PathBuf::from(p.to_str().unwrap().to_string()),
      media_type: msg::MediaType::TypeScript,
      source_code: include_bytes!("./tests/002_hello.ts").to_vec(),
      types_url: None,
      types_header: None,
    };
    let mock_state =
      GlobalState::mock(vec![String::from("deno"), String::from("hello.ts")]);

    let mut module_graph_loader = ModuleGraphLoader::new(
      mock_state.file_fetcher.clone(),
      None,
      Permissions::allow_all(),
      false,
      false,
    );
    module_graph_loader
      .add_to_graph(&specifier, None)
      .await
      .expect("Failed to create graph");
    let module_graph = module_graph_loader.get_graph();

    let result = mock_state
      .ts_compiler
      .compile_module_graph(
        mock_state.clone(),
        &out,
        TargetLib::Main,
        Permissions::allow_all(),
        module_graph,
      )
      .await;
    assert!(result.is_ok());
    let compiled_file = mock_state
      .ts_compiler
      .get_compiled_module(&out.url)
      .unwrap();
    let source_code = compiled_file.code;
    assert!(source_code
      .as_bytes()
      .starts_with(b"\"use strict\";\nconsole.log(\"Hello World\");"));
    let mut lines: Vec<String> =
      source_code.split('\n').map(|s| s.to_string()).collect();
    let last_line = lines.pop().unwrap();
    assert!(last_line.starts_with("//# sourceMappingURL=file://"));

    // Get source map file and assert it has proper URLs
    let source_map = mock_state
      .ts_compiler
      .get_source_map_file(&specifier)
      .expect("Source map not found");
    let source_str = String::from_utf8(source_map.source_code).unwrap();
    let source_json: Value = serde_json::from_str(&source_str).unwrap();

    let js_key = mock_state
      .ts_compiler
      .disk_cache
      .get_cache_filename_with_extension(specifier.as_url(), "js");
    let js_path = mock_state.ts_compiler.disk_cache.location.join(js_key);
    let js_file_url = Url::from_file_path(js_path).unwrap();

    let file_str = source_json.get("file").unwrap().as_str().unwrap();
    assert_eq!(file_str, js_file_url.to_string());

    let sources = source_json.get("sources").unwrap().as_array().unwrap();
    assert_eq!(sources.len(), 1);
    let source = sources.get(0).unwrap().as_str().unwrap();
    assert_eq!(source, specifier.to_string());
  }

  #[tokio::test]
  async fn test_bundle() {
    let p = std::path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
      .parent()
      .unwrap()
      .join("cli/tests/002_hello.ts");
    use deno_core::ModuleSpecifier;
    let module_name =
      ModuleSpecifier::resolve_url_or_path(p.to_str().unwrap()).unwrap();

    let state = GlobalState::mock(vec![
      String::from("deno"),
      p.to_string_lossy().into(),
      String::from("$deno$/bundle.js"),
    ]);

    let result = bundle(
      &state,
      CompilerConfig::load(None).unwrap(),
      module_name,
      None,
      false,
    )
    .await;
    assert!(result.is_ok());
  }

  #[test]
  fn test_source_code_version_hash() {
    assert_eq!(
      "0185b42de0686b4c93c314daaa8dee159f768a9e9a336c2a5e3d5b8ca6c4208c",
      source_code_version_hash(b"1+2", "0.4.0", b"{}")
    );
    // Different source_code should result in different hash.
    assert_eq!(
      "e58631f1b6b6ce2b300b133ec2ad16a8a5ba6b7ecf812a8c06e59056638571ac",
      source_code_version_hash(b"1", "0.4.0", b"{}")
    );
    // Different version should result in different hash.
    assert_eq!(
      "307e6200347a88dbbada453102deb91c12939c65494e987d2d8978f6609b5633",
      source_code_version_hash(b"1", "0.1.0", b"{}")
    );
    // Different config should result in different hash.
    assert_eq!(
      "195eaf104a591d1d7f69fc169c60a41959c2b7a21373cd23a8f675f877ec385f",
      source_code_version_hash(b"1", "0.4.0", b"{\"compilerOptions\": {}}")
    );
  }

  #[test]
  fn test_compile_js() {
    let temp_dir = TempDir::new().expect("tempdir fail");
    let temp_dir_path = temp_dir.path();

    let test_cases = vec![
      // valid JSON
      (r#"{ "compilerOptions": { "checkJs": true } } "#, true),
      // JSON with comment
      (
        r#"{ "compilerOptions": { // force .js file compilation by Deno "checkJs": true } } "#,
        true,
      ),
      // invalid JSON
      (r#"{ "compilerOptions": { "checkJs": true },{ } "#, true),
      // without content
      ("", false),
    ];

    let path = temp_dir_path.join("tsconfig.json");
    let path_str = path.to_str().unwrap().to_string();

    for (json_str, expected) in test_cases {
      deno_fs::write_file(&path, json_str.as_bytes(), 0o666).unwrap();
      let config = CompilerConfig::load(Some(path_str.clone())).unwrap();
      assert_eq!(config.compile_js, expected);
    }
  }

  #[test]
  fn test_compiler_config_load() {
    let temp_dir = TempDir::new().expect("tempdir fail");
    let temp_dir_path = temp_dir.path();
    let path = temp_dir_path.join("doesnotexist.json");
    let path_str = path.to_str().unwrap().to_string();
    let res = CompilerConfig::load(Some(path_str));
    assert!(res.is_err());
  }
}