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

use crate::NodeModuleKind;
use crate::NodePermissions;

use super::NpmResolver;

use deno_core::anyhow;
use deno_core::anyhow::bail;
use deno_core::error::AnyError;
use deno_core::serde_json;
use deno_core::serde_json::Map;
use deno_core::serde_json::Value;
use deno_core::ModuleSpecifier;
use indexmap::IndexMap;
use serde::Serialize;
use std::cell::RefCell;
use std::collections::HashMap;
use std::io::ErrorKind;
use std::path::PathBuf;

thread_local! {
  static CACHE: RefCell<HashMap<PathBuf, PackageJson>> = RefCell::new(HashMap::new());
}

#[derive(Clone, Debug, Serialize)]
pub struct PackageJson {
  pub exists: bool,
  pub exports: Option<Map<String, Value>>,
  pub imports: Option<Map<String, Value>>,
  pub bin: Option<Value>,
  main: Option<String>,   // use .main(...)
  module: Option<String>, // use .main(...)
  pub name: Option<String>,
  pub version: Option<String>,
  pub path: PathBuf,
  pub typ: String,
  pub types: Option<String>,
  pub dependencies: Option<HashMap<String, String>>,
  pub dev_dependencies: Option<HashMap<String, String>>,
  pub scripts: Option<IndexMap<String, String>>,
}

impl PackageJson {
  pub fn empty(path: PathBuf) -> PackageJson {
    PackageJson {
      exists: false,
      exports: None,
      imports: None,
      bin: None,
      main: None,
      module: None,
      name: None,
      version: None,
      path,
      typ: "none".to_string(),
      types: None,
      dependencies: None,
      dev_dependencies: None,
      scripts: None,
    }
  }

  pub fn load(
    fs: &dyn deno_fs::FileSystem,
    resolver: &dyn NpmResolver,
    permissions: &dyn NodePermissions,
    path: PathBuf,
  ) -> Result<PackageJson, AnyError> {
    resolver.ensure_read_permission(permissions, &path)?;
    Self::load_skip_read_permission(fs, path)
  }

  pub fn load_skip_read_permission(
    fs: &dyn deno_fs::FileSystem,
    path: PathBuf,
  ) -> Result<PackageJson, AnyError> {
    assert!(path.is_absolute());

    if CACHE.with(|cache| cache.borrow().contains_key(&path)) {
      return Ok(CACHE.with(|cache| cache.borrow()[&path].clone()));
    }

    let source = match fs.read_text_file_sync(&path) {
      Ok(source) => source,
      Err(err) if err.kind() == ErrorKind::NotFound => {
        return Ok(PackageJson::empty(path));
      }
      Err(err) => bail!(
        "Error loading package.json at {}. {:#}",
        path.display(),
        AnyError::from(err),
      ),
    };

    if source.trim().is_empty() {
      return Ok(PackageJson::empty(path));
    }

    Self::load_from_string(path, source)
  }

  pub fn load_from_string(
    path: PathBuf,
    source: String,
  ) -> Result<PackageJson, AnyError> {
    let package_json: Value = serde_json::from_str(&source)
      .map_err(|err| anyhow::anyhow!("malformed package.json {}", err))?;

    let imports_val = package_json.get("imports");
    let main_val = package_json.get("main");
    let module_val = package_json.get("module");
    let name_val = package_json.get("name");
    let version_val = package_json.get("version");
    let type_val = package_json.get("type");
    let bin = package_json.get("bin").map(ToOwned::to_owned);
    let exports = package_json.get("exports").map(|exports| {
      if is_conditional_exports_main_sugar(exports) {
        let mut map = Map::new();
        map.insert(".".to_string(), exports.to_owned());
        map
      } else {
        exports.as_object().unwrap().to_owned()
      }
    });

    let imports = imports_val
      .and_then(|imp| imp.as_object())
      .map(|imp| imp.to_owned());
    let main = main_val.and_then(|s| s.as_str()).map(|s| s.to_string());
    let name = name_val.and_then(|s| s.as_str()).map(|s| s.to_string());
    let version = version_val.and_then(|s| s.as_str()).map(|s| s.to_string());
    let module = module_val.and_then(|s| s.as_str()).map(|s| s.to_string());

    let dependencies = package_json.get("dependencies").and_then(|d| {
      if d.is_object() {
        let deps: HashMap<String, String> =
          serde_json::from_value(d.to_owned()).unwrap();
        Some(deps)
      } else {
        None
      }
    });
    let dev_dependencies = package_json.get("devDependencies").and_then(|d| {
      if d.is_object() {
        let deps: HashMap<String, String> =
          serde_json::from_value(d.to_owned()).unwrap();
        Some(deps)
      } else {
        None
      }
    });

    let scripts: Option<IndexMap<String, String>> = package_json
      .get("scripts")
      .and_then(|d| serde_json::from_value(d.to_owned()).ok());

    // Ignore unknown types for forwards compatibility
    let typ = if let Some(t) = type_val {
      if let Some(t) = t.as_str() {
        if t != "module" && t != "commonjs" {
          "none".to_string()
        } else {
          t.to_string()
        }
      } else {
        "none".to_string()
      }
    } else {
      "none".to_string()
    };

    // for typescript, it looks for "typings" first, then "types"
    let types = package_json
      .get("typings")
      .or_else(|| package_json.get("types"))
      .and_then(|t| t.as_str().map(|s| s.to_string()));

    let package_json = PackageJson {
      exists: true,
      path,
      main,
      name,
      version,
      module,
      typ,
      types,
      exports,
      imports,
      bin,
      dependencies,
      dev_dependencies,
      scripts,
    };

    CACHE.with(|cache| {
      cache
        .borrow_mut()
        .insert(package_json.path.clone(), package_json.clone());
    });
    Ok(package_json)
  }

  pub fn main(&self, referrer_kind: NodeModuleKind) -> Option<&String> {
    if referrer_kind == NodeModuleKind::Esm && self.typ == "module" {
      self.module.as_ref().or(self.main.as_ref())
    } else {
      self.main.as_ref()
    }
  }

  pub fn specifier(&self) -> ModuleSpecifier {
    ModuleSpecifier::from_file_path(&self.path).unwrap()
  }
}

fn is_conditional_exports_main_sugar(exports: &Value) -> bool {
  if exports.is_string() || exports.is_array() {
    return true;
  }

  if exports.is_null() || !exports.is_object() {
    return false;
  }

  let exports_obj = exports.as_object().unwrap();
  let mut is_conditional_sugar = false;
  let mut i = 0;
  for key in exports_obj.keys() {
    let cur_is_conditional_sugar = key.is_empty() || !key.starts_with('.');
    if i == 0 {
      is_conditional_sugar = cur_is_conditional_sugar;
      i += 1;
    } else if is_conditional_sugar != cur_is_conditional_sugar {
      panic!("\"exports\" cannot contains some keys starting with \'.\' and some not.
        The exports object must either be an object of package subpath keys
        or an object of main entry condition name keys only.")
    }
  }

  is_conditional_sugar
}