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

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

use deno_config::workspace::Workspace;
use deno_core::serde_json;
use deno_package_json::PackageJsonDepValue;
use deno_semver::npm::NpmPackageReqReference;
use deno_semver::package::PackageReq;

use crate::util::path::is_banned_path_char;

#[derive(Debug)]
pub struct InstallNpmRemotePkg {
  pub alias: String,
  pub base_dir: PathBuf,
  pub req: PackageReq,
}

#[derive(Debug)]
pub struct InstallNpmWorkspacePkg {
  pub alias: String,
  pub target_dir: PathBuf,
}

#[derive(Debug, Default)]
pub struct NpmInstallDepsProvider {
  remote_pkgs: Vec<InstallNpmRemotePkg>,
  workspace_pkgs: Vec<InstallNpmWorkspacePkg>,
}

impl NpmInstallDepsProvider {
  pub fn empty() -> Self {
    Self::default()
  }

  pub fn from_workspace(workspace: &Arc<Workspace>) -> Self {
    // todo(dsherret): estimate capacity?
    let mut workspace_pkgs = Vec::new();
    let mut remote_pkgs = Vec::new();
    let workspace_npm_pkgs = workspace.npm_packages();

    for (_, folder) in workspace.config_folders() {
      let mut deno_json_aliases = HashSet::new();

      // deal with the deno.json first because it takes precedence during resolution
      if let Some(deno_json) = &folder.deno_json {
        // don't bother with externally referenced import maps as users
        // should inline their import map to get this behaviour
        if let Some(serde_json::Value::Object(obj)) = &deno_json.json.imports {
          deno_json_aliases.reserve(obj.len());
          let mut pkg_pkgs = Vec::with_capacity(obj.len());
          for (alias, value) in obj {
            let serde_json::Value::String(specifier) = value else {
              continue;
            };
            let Ok(npm_req_ref) = NpmPackageReqReference::from_str(specifier)
            else {
              continue;
            };
            // skip any aliases with banned characters
            if alias.chars().any(|c| c == '\\' || is_banned_path_char(c)) {
              continue;
            }
            deno_json_aliases.insert(alias.to_lowercase());
            let pkg_req = npm_req_ref.into_inner().req;
            let workspace_pkg = workspace_npm_pkgs
              .iter()
              .find(|pkg| pkg.matches_req(&pkg_req));

            if let Some(pkg) = workspace_pkg {
              workspace_pkgs.push(InstallNpmWorkspacePkg {
                alias: alias.to_string(),
                target_dir: pkg.pkg_json.dir_path().to_path_buf(),
              });
            } else {
              pkg_pkgs.push(InstallNpmRemotePkg {
                alias: alias.to_string(),
                base_dir: deno_json.dir_path(),
                req: pkg_req,
              });
            }
          }

          // sort within each package (more like npm resolution)
          pkg_pkgs.sort_by(|a, b| a.alias.cmp(&b.alias));
          remote_pkgs.extend(pkg_pkgs);
        }
      }

      if let Some(pkg_json) = &folder.pkg_json {
        let deps = pkg_json.resolve_local_package_json_deps();
        let mut pkg_pkgs = Vec::with_capacity(deps.len());
        for (alias, dep) in deps {
          let Ok(dep) = dep else {
            continue;
          };
          if deno_json_aliases.contains(&alias.to_lowercase()) {
            // aliases in deno.json take precedence over package.json, so
            // since this can't be resolved don't bother installing it
            continue;
          }
          match dep {
            PackageJsonDepValue::Req(pkg_req) => {
              let workspace_pkg = workspace_npm_pkgs.iter().find(|pkg| {
                pkg.matches_req(&pkg_req)
              // do not resolve to the current package
              && pkg.pkg_json.path != pkg_json.path
              });

              if let Some(pkg) = workspace_pkg {
                workspace_pkgs.push(InstallNpmWorkspacePkg {
                  alias,
                  target_dir: pkg.pkg_json.dir_path().to_path_buf(),
                });
              } else {
                pkg_pkgs.push(InstallNpmRemotePkg {
                  alias,
                  base_dir: pkg_json.dir_path().to_path_buf(),
                  req: pkg_req,
                });
              }
            }
            PackageJsonDepValue::Workspace(version_req) => {
              if let Some(pkg) = workspace_npm_pkgs.iter().find(|pkg| {
                pkg.matches_name_and_version_req(&alias, &version_req)
              }) {
                workspace_pkgs.push(InstallNpmWorkspacePkg {
                  alias,
                  target_dir: pkg.pkg_json.dir_path().to_path_buf(),
                });
              }
            }
          }
        }

        // sort within each package as npm does
        pkg_pkgs.sort_by(|a, b| a.alias.cmp(&b.alias));
        remote_pkgs.extend(pkg_pkgs);
      }
    }

    remote_pkgs.shrink_to_fit();
    workspace_pkgs.shrink_to_fit();
    Self {
      remote_pkgs,
      workspace_pkgs,
    }
  }

  pub fn remote_pkgs(&self) -> &Vec<InstallNpmRemotePkg> {
    &self.remote_pkgs
  }

  pub fn workspace_pkgs(&self) -> &Vec<InstallNpmWorkspacePkg> {
    &self.workspace_pkgs
  }
}