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

use std::path::PathBuf;
use std::sync::Arc;

use deno_core::anyhow::bail;
use deno_core::anyhow::Context;
use deno_core::error::AnyError;
use deno_core::futures::FutureExt;
use deno_core::futures::StreamExt;
use deno_path_util::url_to_file_path;
use deno_semver::jsr::JsrPackageReqReference;
use deno_semver::npm::NpmPackageReqReference;
use deno_semver::package::PackageReq;
use deno_semver::VersionReq;
use jsonc_parser::cst::CstObject;
use jsonc_parser::cst::CstObjectProp;
use jsonc_parser::cst::CstRootNode;
use jsonc_parser::json;

use crate::args::AddFlags;
use crate::args::CacheSetting;
use crate::args::CliOptions;
use crate::args::Flags;
use crate::args::RemoveFlags;
use crate::factory::CliFactory;
use crate::file_fetcher::FileFetcher;
use crate::jsr::JsrFetchResolver;
use crate::npm::NpmFetchResolver;

mod cache_deps;

pub use cache_deps::cache_top_level_deps;

#[derive(Debug, Copy, Clone)]
enum ConfigKind {
  DenoJson,
  PackageJson,
}

struct ConfigUpdater {
  kind: ConfigKind,
  cst: CstRootNode,
  root_object: CstObject,
  path: PathBuf,
  modified: bool,
}

impl ConfigUpdater {
  fn new(
    kind: ConfigKind,
    config_file_path: PathBuf,
  ) -> Result<Self, AnyError> {
    let config_file_contents = std::fs::read_to_string(&config_file_path)
      .with_context(|| {
        format!("Reading config file '{}'", config_file_path.display())
      })?;
    let cst = CstRootNode::parse(&config_file_contents, &Default::default())
      .with_context(|| {
        format!("Parsing config file '{}'", config_file_path.display())
      })?;
    let root_object = cst.object_value_or_set();
    Ok(Self {
      kind,
      cst,
      root_object,
      path: config_file_path,
      modified: false,
    })
  }

  fn display_path(&self) -> String {
    deno_path_util::url_from_file_path(&self.path)
      .map(|u| u.to_string())
      .unwrap_or_else(|_| self.path.display().to_string())
  }

  fn obj(&self) -> &CstObject {
    &self.root_object
  }

  fn contents(&self) -> String {
    self.cst.to_string()
  }

  fn add(&mut self, selected: SelectedPackage, dev: bool) {
    fn insert_index(object: &CstObject, searching_name: &str) -> usize {
      object
        .properties()
        .into_iter()
        .take_while(|prop| {
          let prop_name =
            prop.name().and_then(|name| name.decoded_value().ok());
          match prop_name {
            Some(current_name) => {
              searching_name.cmp(&current_name) == std::cmp::Ordering::Greater
            }
            None => true,
          }
        })
        .count()
    }

    match self.kind {
      ConfigKind::DenoJson => {
        let imports = self.root_object.object_value_or_set("imports");
        let value =
          format!("{}@{}", selected.package_name, selected.version_req);
        if let Some(prop) = imports.get(&selected.import_name) {
          prop.set_value(json!(value));
        } else {
          let index = insert_index(&imports, &selected.import_name);
          imports.insert(index, &selected.import_name, json!(value));
        }
      }
      ConfigKind::PackageJson => {
        let deps_prop = self.root_object.get("dependencies");
        let dev_deps_prop = self.root_object.get("devDependencies");

        let dependencies = if dev {
          self
            .root_object
            .object_value("devDependencies")
            .unwrap_or_else(|| {
              let index = deps_prop
                .as_ref()
                .map(|p| p.property_index() + 1)
                .unwrap_or_else(|| self.root_object.properties().len());
              self
                .root_object
                .insert(index, "devDependencies", json!({}))
                .object_value_or_set()
            })
        } else {
          self
            .root_object
            .object_value("dependencies")
            .unwrap_or_else(|| {
              let index = dev_deps_prop
                .as_ref()
                .map(|p| p.property_index())
                .unwrap_or_else(|| self.root_object.properties().len());
              self
                .root_object
                .insert(index, "dependencies", json!({}))
                .object_value_or_set()
            })
        };
        let other_dependencies = if dev {
          deps_prop.and_then(|p| p.value().and_then(|v| v.as_object()))
        } else {
          dev_deps_prop.and_then(|p| p.value().and_then(|v| v.as_object()))
        };

        let (alias, value) = package_json_dependency_entry(selected);

        if let Some(other) = other_dependencies {
          if let Some(prop) = other.get(&alias) {
            remove_prop_and_maybe_parent_prop(prop);
          }
        }

        if let Some(prop) = dependencies.get(&alias) {
          prop.set_value(json!(value));
        } else {
          let index = insert_index(&dependencies, &alias);
          dependencies.insert(index, &alias, json!(value));
        }
      }
    }

    self.modified = true;
  }

  fn remove(&mut self, package: &str) -> bool {
    let removed = match self.kind {
      ConfigKind::DenoJson => {
        if let Some(prop) = self
          .root_object
          .object_value("imports")
          .and_then(|i| i.get(package))
        {
          remove_prop_and_maybe_parent_prop(prop);
          true
        } else {
          false
        }
      }
      ConfigKind::PackageJson => {
        let deps = [
          self
            .root_object
            .object_value("dependencies")
            .and_then(|deps| deps.get(package)),
          self
            .root_object
            .object_value("devDependencies")
            .and_then(|deps| deps.get(package)),
        ];
        let removed = deps.iter().any(|d| d.is_some());
        for dep in deps.into_iter().flatten() {
          remove_prop_and_maybe_parent_prop(dep);
        }
        removed
      }
    };
    if removed {
      self.modified = true;
    }
    removed
  }

  fn commit(&self) -> Result<(), AnyError> {
    if !self.modified {
      return Ok(());
    }

    let new_text = self.contents();
    std::fs::write(&self.path, new_text).with_context(|| {
      format!("failed writing to '{}'", self.path.display())
    })?;
    Ok(())
  }
}

fn remove_prop_and_maybe_parent_prop(prop: CstObjectProp) {
  let parent = prop.parent().unwrap().as_object().unwrap();
  prop.remove();
  if parent.properties().is_empty() {
    let parent_property = parent.parent().unwrap();
    let root_object = parent_property.parent().unwrap().as_object().unwrap();
    // remove the property
    parent_property.remove();
    root_object.ensure_multiline();
  }
}

fn create_deno_json(
  flags: &Arc<Flags>,
  options: &CliOptions,
) -> Result<CliFactory, AnyError> {
  std::fs::write(options.initial_cwd().join("deno.json"), "{}\n")
    .context("Failed to create deno.json file")?;
  log::info!("Created deno.json configuration file.");
  let factory = CliFactory::from_flags(flags.clone());
  Ok(factory)
}

fn package_json_dependency_entry(
  selected: SelectedPackage,
) -> (String, String) {
  if let Some(npm_package) = selected.package_name.strip_prefix("npm:") {
    if selected.import_name == npm_package {
      (npm_package.into(), selected.version_req)
    } else {
      (
        selected.import_name,
        format!("npm:{}@{}", npm_package, selected.version_req),
      )
    }
  } else if let Some(jsr_package) = selected.package_name.strip_prefix("jsr:") {
    let jsr_package = jsr_package.strip_prefix('@').unwrap_or(jsr_package);
    let scope_replaced = jsr_package.replace('/', "__");
    let version_req =
      format!("npm:@jsr/{scope_replaced}@{}", selected.version_req);
    (selected.import_name, version_req)
  } else {
    (selected.package_name, selected.version_req)
  }
}

#[derive(Clone, Copy)]
/// The name of the subcommand invoking the `add` operation.
pub enum AddCommandName {
  Add,
  Install,
}

impl std::fmt::Display for AddCommandName {
  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
    match self {
      AddCommandName::Add => write!(f, "add"),
      AddCommandName::Install => write!(f, "install"),
    }
  }
}

fn load_configs(
  flags: &Arc<Flags>,
  has_jsr_specifiers: impl FnOnce() -> bool,
) -> Result<(CliFactory, Option<ConfigUpdater>, Option<ConfigUpdater>), AnyError>
{
  let cli_factory = CliFactory::from_flags(flags.clone());
  let options = cli_factory.cli_options()?;
  let start_dir = &options.start_dir;
  let npm_config = match start_dir.maybe_pkg_json() {
    Some(pkg_json) => Some(ConfigUpdater::new(
      ConfigKind::PackageJson,
      pkg_json.path.clone(),
    )?),
    None => None,
  };
  let deno_config = match start_dir.maybe_deno_json() {
    Some(deno_json) => Some(ConfigUpdater::new(
      ConfigKind::DenoJson,
      url_to_file_path(&deno_json.specifier)?,
    )?),
    None => None,
  };

  let (cli_factory, deno_config) = match deno_config {
    Some(config) => (cli_factory, Some(config)),
    None if npm_config.is_some() && !has_jsr_specifiers() => {
      (cli_factory, None)
    }
    _ => {
      let factory = create_deno_json(flags, options)?;
      let options = factory.cli_options()?.clone();
      let deno_json = options
        .start_dir
        .maybe_deno_json()
        .expect("Just created deno.json");
      (
        factory,
        Some(ConfigUpdater::new(
          ConfigKind::DenoJson,
          url_to_file_path(&deno_json.specifier)?,
        )?),
      )
    }
  };
  assert!(deno_config.is_some() || npm_config.is_some());
  Ok((cli_factory, npm_config, deno_config))
}

pub async fn add(
  flags: Arc<Flags>,
  add_flags: AddFlags,
  cmd_name: AddCommandName,
) -> Result<(), AnyError> {
  let (cli_factory, mut npm_config, mut deno_config) =
    load_configs(&flags, || {
      add_flags.packages.iter().any(|s| s.starts_with("jsr:"))
    })?;

  if let Some(deno) = &deno_config {
    if deno.obj().get("importMap").is_some() {
      bail!(
        concat!(
          "`deno {}` is not supported when configuration file contains an \"importMap\" field. ",
          "Inline the import map into the Deno configuration file.\n",
          "    at {}",
        ),
        cmd_name,
        deno.display_path(),
      );
    }
  }

  let http_client = cli_factory.http_client_provider();
  let deps_http_cache = cli_factory.global_http_cache()?;
  let mut deps_file_fetcher = FileFetcher::new(
    deps_http_cache.clone(),
    CacheSetting::ReloadAll,
    true,
    http_client.clone(),
    Default::default(),
    None,
  );
  deps_file_fetcher.set_download_log_level(log::Level::Trace);
  let deps_file_fetcher = Arc::new(deps_file_fetcher);
  let jsr_resolver = Arc::new(JsrFetchResolver::new(deps_file_fetcher.clone()));
  let npm_resolver = Arc::new(NpmFetchResolver::new(deps_file_fetcher));

  let mut selected_packages = Vec::with_capacity(add_flags.packages.len());
  let mut package_reqs = Vec::with_capacity(add_flags.packages.len());

  for entry_text in add_flags.packages.iter() {
    let req = AddRmPackageReq::parse(entry_text).with_context(|| {
      format!("Failed to parse package required: {}", entry_text)
    })?;

    match req {
      Ok(add_req) => package_reqs.push(add_req),
      Err(package_req) => {
        if jsr_resolver.req_to_nv(&package_req).await.is_some() {
          bail!(
            "{entry_text} is missing a prefix. Did you mean `{}`?",
            crate::colors::yellow(format!("deno {cmd_name} jsr:{package_req}"))
          )
        } else if npm_resolver.req_to_nv(&package_req).await.is_some() {
          bail!(
            "{entry_text} is missing a prefix. Did you mean `{}`?",
            crate::colors::yellow(format!("deno {cmd_name} npm:{package_req}"))
          )
        } else {
          bail!(
            "{} was not found in either jsr or npm.",
            crate::colors::red(entry_text)
          );
        }
      }
    }
  }

  let package_futures = package_reqs
    .into_iter()
    .map({
      let jsr_resolver = jsr_resolver.clone();
      move |package_req| {
        find_package_and_select_version_for_req(
          jsr_resolver.clone(),
          npm_resolver.clone(),
          package_req,
        )
        .boxed_local()
      }
    })
    .collect::<Vec<_>>();

  let stream_of_futures = deno_core::futures::stream::iter(package_futures);
  let mut buffered = stream_of_futures.buffered(10);

  while let Some(package_and_version_result) = buffered.next().await {
    let package_and_version = package_and_version_result?;

    match package_and_version {
      PackageAndVersion::NotFound {
        package: package_name,
        found_npm_package,
        package_req,
      } => {
        if found_npm_package {
          bail!("{} was not found, but a matching npm package exists. Did you mean `{}`?", crate::colors::red(package_name), crate::colors::yellow(format!("deno {cmd_name} npm:{package_req}")));
        } else {
          bail!("{} was not found.", crate::colors::red(package_name));
        }
      }
      PackageAndVersion::Selected(selected) => {
        selected_packages.push(selected);
      }
    }
  }

  let dev = add_flags.dev;
  for selected_package in selected_packages {
    log::info!(
      "Add {}{}{}",
      crate::colors::green(&selected_package.package_name),
      crate::colors::gray("@"),
      selected_package.selected_version
    );

    if selected_package.package_name.starts_with("npm:") {
      if let Some(npm) = &mut npm_config {
        npm.add(selected_package, dev);
      } else {
        deno_config.as_mut().unwrap().add(selected_package, dev);
      }
    } else if let Some(deno) = &mut deno_config {
      deno.add(selected_package, dev);
    } else {
      npm_config.as_mut().unwrap().add(selected_package, dev);
    }
  }

  if let Some(npm) = npm_config {
    npm.commit()?;
  }
  if let Some(deno) = deno_config {
    deno.commit()?;
  }

  npm_install_after_modification(flags, Some(jsr_resolver)).await?;

  Ok(())
}

struct SelectedPackage {
  import_name: String,
  package_name: String,
  version_req: String,
  selected_version: String,
}

enum PackageAndVersion {
  NotFound {
    package: String,
    found_npm_package: bool,
    package_req: PackageReq,
  },
  Selected(SelectedPackage),
}

async fn find_package_and_select_version_for_req(
  jsr_resolver: Arc<JsrFetchResolver>,
  npm_resolver: Arc<NpmFetchResolver>,
  add_package_req: AddRmPackageReq,
) -> Result<PackageAndVersion, AnyError> {
  match add_package_req.value {
    AddRmPackageReqValue::Jsr(req) => {
      let jsr_prefixed_name = format!("jsr:{}", &req.name);
      let Some(nv) = jsr_resolver.req_to_nv(&req).await else {
        if npm_resolver.req_to_nv(&req).await.is_some() {
          return Ok(PackageAndVersion::NotFound {
            package: jsr_prefixed_name,
            found_npm_package: true,
            package_req: req,
          });
        }

        return Ok(PackageAndVersion::NotFound {
          package: jsr_prefixed_name,
          found_npm_package: false,
          package_req: req,
        });
      };
      let range_symbol = if req.version_req.version_text().starts_with('~') {
        "~"
      } else if req.version_req.version_text() == nv.version.to_string() {
        ""
      } else {
        "^"
      };
      Ok(PackageAndVersion::Selected(SelectedPackage {
        import_name: add_package_req.alias,
        package_name: jsr_prefixed_name,
        version_req: format!("{}{}", range_symbol, &nv.version),
        selected_version: nv.version.to_string(),
      }))
    }
    AddRmPackageReqValue::Npm(req) => {
      let npm_prefixed_name = format!("npm:{}", &req.name);
      let Some(nv) = npm_resolver.req_to_nv(&req).await else {
        return Ok(PackageAndVersion::NotFound {
          package: npm_prefixed_name,
          found_npm_package: false,
          package_req: req,
        });
      };

      let range_symbol = if req.version_req.version_text().starts_with('~') {
        "~"
      } else if req.version_req.version_text() == nv.version.to_string() {
        ""
      } else {
        "^"
      };

      Ok(PackageAndVersion::Selected(SelectedPackage {
        import_name: add_package_req.alias,
        package_name: npm_prefixed_name,
        version_req: format!("{}{}", range_symbol, &nv.version),
        selected_version: nv.version.to_string(),
      }))
    }
  }
}

#[derive(Debug, PartialEq, Eq)]
enum AddRmPackageReqValue {
  Jsr(PackageReq),
  Npm(PackageReq),
}

#[derive(Debug, PartialEq, Eq)]
struct AddRmPackageReq {
  alias: String,
  value: AddRmPackageReqValue,
}

impl AddRmPackageReq {
  pub fn parse(entry_text: &str) -> Result<Result<Self, PackageReq>, AnyError> {
    enum Prefix {
      Jsr,
      Npm,
    }

    fn parse_prefix(text: &str) -> (Option<Prefix>, &str) {
      if let Some(text) = text.strip_prefix("jsr:") {
        (Some(Prefix::Jsr), text)
      } else if let Some(text) = text.strip_prefix("npm:") {
        (Some(Prefix::Npm), text)
      } else {
        (None, text)
      }
    }

    // parse the following:
    // - alias@npm:<package_name>
    // - other_alias@npm:<package_name>
    // - @alias/other@jsr:<package_name>
    fn parse_alias(entry_text: &str) -> Option<(&str, &str)> {
      for prefix in ["npm:", "jsr:"] {
        let Some(location) = entry_text.find(prefix) else {
          continue;
        };
        let prefix = &entry_text[..location];
        if let Some(alias) = prefix.strip_suffix('@') {
          return Some((alias, &entry_text[location..]));
        }
      }
      None
    }

    let (maybe_prefix, entry_text) = parse_prefix(entry_text);
    let (prefix, maybe_alias, entry_text) = match maybe_prefix {
      Some(prefix) => (prefix, None, entry_text),
      None => match parse_alias(entry_text) {
        Some((alias, text)) => {
          let (maybe_prefix, entry_text) = parse_prefix(text);
          if maybe_prefix.is_none() {
            return Ok(Err(PackageReq::from_str(entry_text)?));
          }

          (maybe_prefix.unwrap(), Some(alias.to_string()), entry_text)
        }
        None => return Ok(Err(PackageReq::from_str(entry_text)?)),
      },
    };

    match prefix {
      Prefix::Jsr => {
        let req_ref =
          JsrPackageReqReference::from_str(&format!("jsr:{}", entry_text))?;
        let package_req = req_ref.into_inner().req;
        Ok(Ok(AddRmPackageReq {
          alias: maybe_alias.unwrap_or_else(|| package_req.name.to_string()),
          value: AddRmPackageReqValue::Jsr(package_req),
        }))
      }
      Prefix::Npm => {
        let req_ref =
          NpmPackageReqReference::from_str(&format!("npm:{}", entry_text))?;
        let mut package_req = req_ref.into_inner().req;
        // deno_semver defaults to a version req of `*` if none is specified
        // we want to default to `latest` instead
        if package_req.version_req == *deno_semver::WILDCARD_VERSION_REQ
          && package_req.version_req.version_text() == "*"
          && !entry_text.contains("@*")
        {
          package_req.version_req = VersionReq::from_raw_text_and_inner(
            "latest".into(),
            deno_semver::RangeSetOrTag::Tag("latest".into()),
          );
        }
        Ok(Ok(AddRmPackageReq {
          alias: maybe_alias.unwrap_or_else(|| package_req.name.to_string()),
          value: AddRmPackageReqValue::Npm(package_req),
        }))
      }
    }
  }
}

pub async fn remove(
  flags: Arc<Flags>,
  remove_flags: RemoveFlags,
) -> Result<(), AnyError> {
  let (_, npm_config, deno_config) = load_configs(&flags, || false)?;

  let mut configs = [npm_config, deno_config];

  let mut removed_packages = vec![];

  for package in &remove_flags.packages {
    let req = AddRmPackageReq::parse(package).with_context(|| {
      format!("Failed to parse package required: {}", package)
    })?;
    let mut parsed_pkg_name = None;
    for config in configs.iter_mut().flatten() {
      match &req {
        Ok(rm_pkg) => {
          if config.remove(&rm_pkg.alias) && parsed_pkg_name.is_none() {
            parsed_pkg_name = Some(rm_pkg.alias.clone());
          }
        }
        Err(pkg) => {
          // An alias or a package name without registry/version
          // constraints. Try to remove the package anyway.
          if config.remove(&pkg.name) && parsed_pkg_name.is_none() {
            parsed_pkg_name = Some(pkg.name.clone());
          }
        }
      }
    }
    if let Some(pkg) = parsed_pkg_name {
      removed_packages.push(pkg);
    }
  }

  if removed_packages.is_empty() {
    log::info!("No packages were removed");
  } else {
    for package in &removed_packages {
      log::info!("Removed {}", crate::colors::green(package));
    }
    for config in configs.into_iter().flatten() {
      config.commit()?;
    }

    npm_install_after_modification(flags, None).await?;
  }

  Ok(())
}

async fn npm_install_after_modification(
  flags: Arc<Flags>,
  // explicitly provided to prevent redownloading
  jsr_resolver: Option<Arc<crate::jsr::JsrFetchResolver>>,
) -> Result<(), AnyError> {
  // clear the previously cached package.json from memory before reloading it
  node_resolver::PackageJsonThreadLocalCache::clear();

  // make a new CliFactory to pick up the updated config file
  let cli_factory = CliFactory::from_flags(flags);
  // surface any errors in the package.json
  let npm_resolver = cli_factory.npm_resolver().await?;
  if let Some(npm_resolver) = npm_resolver.as_managed() {
    npm_resolver.ensure_no_pkg_json_dep_errors()?;
  }
  // npm install
  cache_deps::cache_top_level_deps(&cli_factory, jsr_resolver).await?;

  if let Some(lockfile) = cli_factory.cli_options()?.maybe_lockfile() {
    lockfile.write_if_changed()?;
  }

  Ok(())
}

#[cfg(test)]
mod test {
  use super::*;

  #[test]
  fn test_parse_add_package_req() {
    assert_eq!(
      AddRmPackageReq::parse("jsr:foo").unwrap().unwrap(),
      AddRmPackageReq {
        alias: "foo".to_string(),
        value: AddRmPackageReqValue::Jsr(PackageReq::from_str("foo").unwrap())
      }
    );
    assert_eq!(
      AddRmPackageReq::parse("alias@jsr:foo").unwrap().unwrap(),
      AddRmPackageReq {
        alias: "alias".to_string(),
        value: AddRmPackageReqValue::Jsr(PackageReq::from_str("foo").unwrap())
      }
    );
    assert_eq!(
      AddRmPackageReq::parse("@alias/pkg@npm:foo")
        .unwrap()
        .unwrap(),
      AddRmPackageReq {
        alias: "@alias/pkg".to_string(),
        value: AddRmPackageReqValue::Npm(
          PackageReq::from_str("foo@latest").unwrap()
        )
      }
    );
    assert_eq!(
      AddRmPackageReq::parse("@alias/pkg@jsr:foo")
        .unwrap()
        .unwrap(),
      AddRmPackageReq {
        alias: "@alias/pkg".to_string(),
        value: AddRmPackageReqValue::Jsr(PackageReq::from_str("foo").unwrap())
      }
    );
    assert_eq!(
      AddRmPackageReq::parse("alias@jsr:foo@^1.5.0")
        .unwrap()
        .unwrap(),
      AddRmPackageReq {
        alias: "alias".to_string(),
        value: AddRmPackageReqValue::Jsr(
          PackageReq::from_str("foo@^1.5.0").unwrap()
        )
      }
    );
    assert_eq!(
      AddRmPackageReq::parse("@scope/pkg@tag")
        .unwrap()
        .unwrap_err()
        .to_string(),
      "@scope/pkg@tag",
    );
  }
}