// Copyright 2018-2026 the Deno authors. MIT license.

use std::io::Read;
use std::sync::Arc;

use deno_cache_dir::file_fetcher::File;
use deno_config::deno_json::NodeModulesDirMode;
use deno_core::anyhow::Context;
use deno_core::error::AnyError;
use deno_core::futures::FutureExt;
use deno_lib::worker::LibWorkerFactoryRoots;
use deno_npm_installer::PackageCaching;
use deno_npm_installer::graph::NpmCachingStrategy;
use deno_path_util::resolve_url_or_path;
use deno_runtime::WorkerExecutionMode;

use crate::args::EvalFlags;
use crate::args::Flags;
use crate::args::RunFlags;
use crate::args::WatchFlagsWithPaths;
use crate::factory::CliFactory;
use crate::util;
use crate::util::file_watcher::WatcherRestartMode;

pub mod hmr;

pub fn check_permission_before_script(flags: &Flags) {
  if !flags.has_permission() && flags.has_permission_in_argv() {
    log::warn!(
      "{}",
      crate::colors::yellow(
        r#"Permission flags have likely been incorrectly set after the script argument.
To grant permissions, set them before the script argument. For example:
    deno run --allow-read=. main.js"#
      )
    );
  }
}

pub fn set_npm_user_agent() {
  static ONCE: std::sync::Once = std::sync::Once::new();
  ONCE.call_once(|| {
    // SAFETY: guarded by Once so only called once from a single thread
    unsafe {
      std::env::set_var(
        crate::npm::NPM_CONFIG_USER_AGENT_ENV_VAR,
        crate::npm::get_npm_config_user_agent(),
      )
    };
  });
}

pub async fn run_script(
  mode: WorkerExecutionMode,
  flags: Arc<Flags>,
  watch: Option<WatchFlagsWithPaths>,
  unconfigured_runtime: Option<deno_runtime::UnconfiguredRuntime>,
  roots: LibWorkerFactoryRoots,
) -> Result<i32, AnyError> {
  check_permission_before_script(&flags);

  if let Some(watch_flags) = watch {
    return run_with_watch(mode, flags, watch_flags).boxed_local().await;
  }

  // TODO(bartlomieju): actually I think it will also fail if there's an import
  // map specified and bare specifier is used on the command line
  let factory = CliFactory::from_flags(flags);
  let cli_options = factory.cli_options()?;
  let deno_dir = factory.deno_dir()?;
  let http_client = factory.http_client_provider();
  let workspace_resolver = factory.workspace_resolver().await?;
  let node_resolver = factory.node_resolver().await?;
  // Run a background task that checks for available upgrades or output
  // if an earlier run of this background task found a new version of Deno.
  #[cfg(feature = "upgrade")]
  super::upgrade::check_for_upgrades(
    http_client.clone(),
    deno_dir.upgrade_check_file_path(),
  );

  let main_module_resolver = crate::args::WorkspaceMainModuleResolver::new(
    workspace_resolver.clone(),
    node_resolver.clone(),
  );
  let main_module = cli_options
    .resolve_main_module_with_resolver(Some(&main_module_resolver))?;
  let preload_modules =
    cli_options.preload_modules_with_resolver(Some(&main_module_resolver))?;
  let require_modules = cli_options.require_modules()?;

  if main_module.scheme() == "npm" {
    set_npm_user_agent();
  }

  maybe_npm_install(&factory).await?;

  let worker_factory = factory
    .create_cli_main_worker_factory_with_roots(roots)
    .await?;
  let mut worker = worker_factory
    .create_main_worker_with_unconfigured_runtime(
      mode,
      main_module.clone(),
      preload_modules,
      require_modules,
      unconfigured_runtime,
    )
    .await
    .inspect_err(|e| deno_telemetry::report_event("boot_failure", e))?;

  let exit_code = worker
    .run()
    .await
    .inspect_err(|e| deno_telemetry::report_event("uncaught_exception", e))?;
  Ok(exit_code)
}

pub async fn run_from_stdin(
  flags: Arc<Flags>,
  unconfigured_runtime: Option<deno_runtime::UnconfiguredRuntime>,
  roots: LibWorkerFactoryRoots,
) -> Result<i32, AnyError> {
  let factory = CliFactory::from_flags(flags);
  let cli_options = factory.cli_options()?;
  let main_module = cli_options.resolve_main_module()?;
  let preload_modules = cli_options.preload_modules()?;
  let require_modules = cli_options.require_modules()?;

  maybe_npm_install(&factory).await?;

  let file_fetcher = factory.file_fetcher()?;
  let worker_factory = factory
    .create_cli_main_worker_factory_with_roots(roots)
    .await?;
  let mut source = Vec::new();
  std::io::stdin().read_to_end(&mut source)?;
  // Save a fake file into file fetcher cache
  // to allow module access by TS compiler
  file_fetcher.insert_memory_files(File {
    url: main_module.clone(),
    mtime: None,
    maybe_headers: None,
    source: source.into(),
    loaded_from: deno_cache_dir::file_fetcher::LoadedFrom::Local,
  });

  let mut worker = worker_factory
    .create_main_worker_with_unconfigured_runtime(
      WorkerExecutionMode::Run,
      main_module.clone(),
      preload_modules,
      require_modules,
      unconfigured_runtime,
    )
    .await?;
  let exit_code = worker.run().await?;
  Ok(exit_code)
}

// TODO(bartlomieju): this function is not handling `exit_code` set by the runtime
// code properly.
async fn run_with_watch(
  mode: WorkerExecutionMode,
  flags: Arc<Flags>,
  watch_flags: WatchFlagsWithPaths,
) -> Result<i32, AnyError> {
  util::file_watcher::watch_recv(
    flags,
    util::file_watcher::PrintConfig::new_with_banner(
      if watch_flags.hmr { "HMR" } else { "Watcher" },
      "Process",
      !watch_flags.no_clear_screen,
    ),
    WatcherRestartMode::Automatic,
    move |flags, watcher_communicator, changed_paths| {
      watcher_communicator.show_path_changed(changed_paths.clone());
      Ok(async move {
        let factory = CliFactory::from_flags_for_watcher(
          flags,
          watcher_communicator.clone(),
        );
        let cli_options = factory.cli_options()?;
        let main_module = cli_options.resolve_main_module()?;
        let preload_modules = cli_options.preload_modules()?;
        let require_modules = cli_options.require_modules()?;

        if main_module.scheme() == "npm" {
          set_npm_user_agent();
        }

        maybe_npm_install(&factory).await?;

        let _ = watcher_communicator.watch_paths(cli_options.watch_paths());

        let mut worker = factory
          .create_cli_main_worker_factory()
          .await?
          .create_main_worker(
            mode,
            main_module.clone(),
            preload_modules,
            require_modules,
          )
          .await?;

        if watch_flags.hmr {
          worker.run().await?;
        } else {
          worker.run_for_watcher().await?;
        }

        Ok(())
      })
    },
  )
  .boxed_local()
  .await?;

  Ok(0)
}

pub async fn eval_command(
  flags: Arc<Flags>,
  eval_flags: EvalFlags,
) -> Result<i32, AnyError> {
  // Auto-detect CJS vs ESM if --ext was not explicitly provided.
  // Default is ESM (preserving existing behavior). Only switch to CJS if
  // the code contains CJS-specific patterns like require() calls.
  // We check for import/export declarations first — if present, it's
  // definitely ESM. If absent, we look for CJS patterns to decide.
  let flags = if flags.ext.is_none() {
    let source_code = if eval_flags.print {
      format!("console.log({})", &eval_flags.code)
    } else {
      eval_flags.code.clone()
    };
    let specifier = deno_core::url::Url::parse("file:///eval.js").unwrap();
    let is_script = deno_ast::parse_program(deno_ast::ParseParams {
      specifier,
      text: source_code.clone().into(),
      media_type: deno_ast::MediaType::JavaScript,
      capture_tokens: false,
      scope_analysis: false,
      maybe_syntax: None,
    })
    .map(|parsed| parsed.compute_is_script())
    .unwrap_or(true);
    // Only treat as CJS if it parses as a script AND contains CJS patterns.
    // This preserves backward compatibility: code without imports/exports
    // defaults to ESM (the longstanding deno eval behavior).
    let has_cjs_patterns = is_script
      && (source_code.contains("require(")
        || source_code.contains("module.exports")
        || source_code.contains("exports.")
        || source_code.contains("__dirname")
        || source_code.contains("__filename"));
    if has_cjs_patterns {
      let mut flags = (*flags).clone();
      flags.ext = Some("cjs".to_string());
      Arc::new(flags)
    } else {
      flags
    }
  } else {
    flags
  };
  let factory = CliFactory::from_flags(flags);
  let cli_options = factory.cli_options()?;
  let file_fetcher = factory.file_fetcher()?;
  let main_module = cli_options.resolve_main_module()?;
  let preload_modules = cli_options.preload_modules()?;
  let require_modules = cli_options.require_modules()?;

  maybe_npm_install(&factory).await?;

  // Create a dummy source file.
  let source_code = if eval_flags.print {
    format!("console.log({})", eval_flags.code)
  } else {
    eval_flags.code
  };
  // Match Node's `[eval]` URL for `-e` scripts so inspector clients (and
  // Node compat tests) see the same script URL. V8 honors the
  // `//# sourceURL=` comment for both classic scripts and ES modules.
  // Appended (not prepended) so user line numbers are preserved.
  let source_code = format!("{source_code}\n//# sourceURL=[eval]\n");

  // Save a fake file into file fetcher cache
  // to allow module access by TS compiler.
  file_fetcher.insert_memory_files(File {
    url: main_module.clone(),
    mtime: None,
    maybe_headers: None,
    source: source_code.into_bytes().into(),
    loaded_from: deno_cache_dir::file_fetcher::LoadedFrom::Local,
  });

  let worker_factory = factory.create_cli_main_worker_factory().await?;
  let mut worker = worker_factory
    .create_main_worker(
      WorkerExecutionMode::Eval,
      main_module.clone(),
      preload_modules,
      require_modules,
    )
    .await?;
  let exit_code = worker.run().await?;
  Ok(exit_code)
}

pub async fn maybe_npm_install(factory: &CliFactory) -> Result<(), AnyError> {
  let cli_options = factory.cli_options()?;
  // ensure an "npm install" is done if the user has explicitly
  // opted into using a managed node_modules directory
  if cli_options.specified_node_modules_dir()? == Some(NodeModulesDirMode::Auto)
    && let Some(npm_installer) = factory.npm_installer_if_managed().await?
  {
    let _clear_guard = factory
      .text_only_progress_bar()
      .deferred_keep_initialize_alive();
    let already_done = npm_installer
      .ensure_top_level_package_json_install()
      .await?;
    if !already_done
      && matches!(
        cli_options.default_npm_caching_strategy(),
        NpmCachingStrategy::Eager
      )
    {
      npm_installer.cache_packages(PackageCaching::All).await?;
    }
  }
  Ok(())
}

pub async fn run_eszip(
  flags: Arc<Flags>,
  run_flags: RunFlags,
  unconfigured_runtime: Option<deno_runtime::UnconfiguredRuntime>,
  roots: LibWorkerFactoryRoots,
) -> Result<i32, AnyError> {
  // TODO(bartlomieju): actually I think it will also fail if there's an import
  // map specified and bare specifier is used on the command line
  let factory = CliFactory::from_flags(flags.clone());
  let cli_options = factory.cli_options()?;

  // entrypoint#path1,path2,...
  let (entrypoint, _files) = run_flags
    .script
    .split_once("#")
    .with_context(|| "eszip: invalid script string")?;

  let mode = WorkerExecutionMode::Run;
  let main_module = resolve_url_or_path(entrypoint, cli_options.initial_cwd())?;
  let preload_modules = cli_options.preload_modules()?;
  let require_modules = cli_options.require_modules()?;

  let worker_factory = factory
    .create_cli_main_worker_factory_with_roots(roots)
    .await?;
  let mut worker = worker_factory
    .create_main_worker_with_unconfigured_runtime(
      mode,
      main_module.clone(),
      preload_modules,
      require_modules,
      unconfigured_runtime,
    )
    .await?;

  let exit_code = worker.run().await?;
  Ok(exit_code)
}
