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

use std::collections::BTreeMap;
use std::sync::atomic::AtomicBool;
use std::sync::Arc;

use deno_core::error::AnyError;
use deno_graph::npm::NpmPackageReq;

use super::NpmRegistryApi;
use super::NpmResolution;

#[derive(Debug)]
struct PackageJsonDepsInstallerInner {
  has_installed: AtomicBool,
  npm_registry_api: NpmRegistryApi,
  npm_resolution: NpmResolution,
  package_deps: BTreeMap<String, NpmPackageReq>,
}

/// Holds and controls installing dependencies from package.json.
#[derive(Debug, Clone, Default)]
pub struct PackageJsonDepsInstaller(Option<Arc<PackageJsonDepsInstallerInner>>);

impl PackageJsonDepsInstaller {
  pub fn new(
    npm_registry_api: NpmRegistryApi,
    npm_resolution: NpmResolution,
    deps: Option<BTreeMap<String, NpmPackageReq>>,
  ) -> Self {
    Self(deps.map(|package_deps| {
      Arc::new(PackageJsonDepsInstallerInner {
        has_installed: AtomicBool::new(false),
        npm_registry_api,
        npm_resolution,
        package_deps,
      })
    }))
  }

  pub fn package_deps(&self) -> Option<&BTreeMap<String, NpmPackageReq>> {
    self.0.as_ref().map(|inner| &inner.package_deps)
  }

  /// Gets if the package.json has the specified package name.
  pub fn has_package_name(&self, name: &str) -> bool {
    if let Some(package_deps) = self.package_deps() {
      // ensure this looks at the package name and not the
      // bare specifiers (do not look at the keys!)
      package_deps.values().any(|v| v.name == name)
    } else {
      false
    }
  }

  /// Installs the top level dependencies in the package.json file
  /// without going through and resolving the descendant dependencies yet.
  pub async fn ensure_top_level_install(&self) -> Result<(), AnyError> {
    use std::sync::atomic::Ordering;
    let inner = match &self.0 {
      Some(inner) => inner,
      None => return Ok(()),
    };

    if inner.has_installed.swap(true, Ordering::SeqCst) {
      return Ok(()); // already installed by something else
    }

    let mut package_reqs =
      inner.package_deps.values().cloned().collect::<Vec<_>>();
    package_reqs.sort(); // deterministic resolution

    inner
      .npm_registry_api
      .cache_in_parallel(
        package_reqs.iter().map(|req| req.name.clone()).collect(),
      )
      .await?;

    for package_req in package_reqs {
      inner
        .npm_resolution
        .resolve_package_req_as_pending(&package_req)?;
    }

    Ok(())
  }
}