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

use std::sync::Arc;

use deno_core::error::AnyError;
use deno_core::futures::TryFutureExt;
use deno_core::ModuleSpecifier;
use deno_runtime_tauri::deno_permissions::Permissions;
use deno_runtime_tauri::deno_permissions::PermissionsContainer;

use super::run::check_permission_before_script;
use super::run::maybe_npm_install;
use crate::args::Flags;
use crate::args::ServeFlags;
use crate::args::WatchFlagsWithPaths;
use crate::factory::CliFactory;
use crate::util::file_watcher::WatcherRestartMode;
use crate::worker::CliMainWorkerFactory;

pub async fn serve(
    flags: Arc<Flags>,
    serve_flags: ServeFlags,
) -> Result<i32, AnyError> {
    check_permission_before_script(&flags);

    if let Some(watch_flags) = serve_flags.watch {
        return serve_with_watch(flags, watch_flags, serve_flags.worker_count)
            .await;
    }

    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();

    // 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 = cli_options.resolve_main_module()?;

    maybe_npm_install(&factory).await?;

    let permissions = PermissionsContainer::new(Permissions::from_options(
        &cli_options.permissions_options()?,
    )?);
    let worker_factory = factory.create_cli_main_worker_factory().await?;

    do_serve(
        worker_factory,
        main_module,
        permissions,
        serve_flags.worker_count,
        false,
    )
        .await
}

async fn do_serve(
    worker_factory: CliMainWorkerFactory,
    main_module: ModuleSpecifier,
    permissions: PermissionsContainer,
    worker_count: Option<usize>,
    hmr: bool,
) -> Result<i32, AnyError> {
    let mut worker = worker_factory
        .create_main_worker(
            deno_runtime_tauri::WorkerExecutionMode::Serve {
                is_main: true,
                worker_count,
            },
            main_module.clone(),
            permissions.clone(),
        )
        .await?;
    let worker_count = match worker_count {
        None | Some(1) => return worker.run().await,
        Some(c) => c,
    };

    let main = deno_core::unsync::spawn(async move { worker.run().await });

    let extra_workers = worker_count.saturating_sub(1);

    let mut channels = Vec::with_capacity(extra_workers);
    for i in 0..extra_workers {
        let worker_factory = worker_factory.clone();
        let main_module = main_module.clone();
        let permissions = permissions.clone();
        let (tx, rx) = tokio::sync::oneshot::channel();
        channels.push(rx);
        std::thread::Builder::new()
            .name(format!("serve-worker-{i}"))
            .spawn(move || {
                deno_runtime_tauri::tokio_util::create_and_run_current_thread(async move {
                    let result =
                        run_worker(i, worker_factory, main_module, permissions, hmr).await;
                    let _ = tx.send(result);
                });
            })?;
    }

    let (main_result, worker_results) = tokio::try_join!(
    main.map_err(AnyError::from),
    deno_core::futures::future::try_join_all(
      channels.into_iter().map(|r| r.map_err(AnyError::from))
    )
  )?;

    let mut exit_code = main_result?;
    for res in worker_results {
        let ret = res?;
        if ret != 0 && exit_code == 0 {
            exit_code = ret;
        }
    }
    Ok(exit_code)

    // main.await?
}

async fn run_worker(
    worker_count: usize,
    worker_factory: CliMainWorkerFactory,
    main_module: ModuleSpecifier,
    permissions: PermissionsContainer,
    hmr: bool,
) -> Result<i32, AnyError> {
    let mut worker = worker_factory
        .create_main_worker(
            deno_runtime_tauri::WorkerExecutionMode::Serve {
                is_main: false,
                worker_count: Some(worker_count),
            },
            main_module,
            permissions,
        )
        .await?;
    if hmr {
        worker.run_for_watcher().await?;
        Ok(0)
    } else {
        worker.run().await
    }
}

async fn serve_with_watch(
    flags: Arc<Flags>,
    watch_flags: WatchFlagsWithPaths,
    worker_count: Option<usize>,
) -> Result<i32, AnyError> {
    let hmr = watch_flags.hmr;
    crate::util::file_watcher::watch_recv(
        flags,
        crate::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| {
            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()?;

                maybe_npm_install(&factory).await?;

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

                let permissions = PermissionsContainer::new(Permissions::from_options(
                    &cli_options.permissions_options()?,
                )?);
                let worker_factory = factory.create_cli_main_worker_factory().await?;

                do_serve(worker_factory, main_module, permissions, worker_count, hmr)
                    .await?;

                Ok(())
            })
        },
    )
        .await?;
    Ok(0)
}