use crate::accountmanager::legacy::SdaManifest;
pub use crate::encryption::EncryptionScheme;
use crate::encryption::EntryEncryptor;
use log::*;
use rayon::prelude::*;
use secrecy::{ExposeSecret, SecretString};
use std::collections::HashMap;
use std::fs::File;
use std::io::{BufReader, Read, Write};
use std::path::Path;
use std::sync::{Arc, Mutex};
use steamguard::SteamGuardAccount;
use thiserror::Error;

mod legacy;
pub mod manifest;
pub mod migrate;

pub use manifest::*;

#[derive(Debug, Default)]
pub struct AccountManager {
	manifest: Manifest,
	accounts: HashMap<String, Arc<Mutex<SteamGuardAccount>>>,
	folder: String,
	passkey: Option<SecretString>,
}

impl AccountManager {
	/// `path` should be the path to manifest.json
	pub fn new(path: &Path) -> Self {
		Self {
			folder: String::from(path.parent().unwrap().to_str().unwrap()),
			..Default::default()
		}
	}

	pub fn from_manifest(manifest: Manifest, folder: String) -> Self {
		Self {
			manifest,
			folder,
			..Default::default()
		}
	}

	pub fn register_accounts(&mut self, accounts: Vec<SteamGuardAccount>) {
		for account in accounts {
			self.register_loaded_account(Arc::new(Mutex::new(account)));
		}
	}

	pub fn load(path: &Path) -> anyhow::Result<Self, ManifestLoadError> {
		debug!("loading manifest: {:?}", &path);
		let file = File::open(path)?;
		let mut reader = BufReader::new(file);
		let mut buffer = String::new();
		reader.read_to_string(&mut buffer)?;
		let mut deser = serde_json::Deserializer::from_str(&buffer);
		let manifest: Manifest = match serde_path_to_error::deserialize(&mut deser) {
			Ok(m) => m,
			Err(orig_err) => match serde_json::from_str::<SdaManifest>(&buffer) {
				Ok(_) => return Err(ManifestLoadError::MigrationNeeded)?,
				Err(_) => return Err(orig_err)?,
			},
		};
		if manifest.version != CURRENT_MANIFEST_VERSION {
			return Err(ManifestLoadError::MigrationNeeded)?;
		}
		let accountmanager = Self {
			manifest,
			folder: String::from(path.parent().unwrap().to_str().unwrap()),
			..Default::default()
		};
		Ok(accountmanager)
	}

	/// Tells the manager to keep track of the encryption passkey, and use it for encryption when loading or saving accounts.
	pub fn submit_passkey(&mut self, passkey: Option<SecretString>) {
		if let Some(p) = passkey.as_ref() {
			if p.expose_secret().is_empty() {
				panic!("Encryption passkey cannot be empty");
			}
		}
		if passkey.is_some() {
			debug!("passkey was submitted to manifest");
		} else {
			debug!("passkey was revoked from manifest");
		}
		self.passkey = passkey;
	}

	pub fn keyring_id(&self) -> Option<&String> {
		self.manifest.keyring_id.as_ref()
	}

	pub fn set_keyring_id(&mut self, keyring_id: String) {
		self.manifest.keyring_id = Some(keyring_id);
	}

	pub fn clear_keyring_id(&mut self) {
		self.manifest.keyring_id = None;
	}

	/// Loads all accounts, and registers them.
	pub fn load_accounts(&mut self) -> anyhow::Result<(), ManifestAccountLoadError> {
		let accounts = self
			.manifest
			.entries
			.par_iter()
			.map(|entry| self.load_account_by_entry(entry))
			.collect::<Vec<_>>();
		for account in accounts {
			self.register_loaded_account(account?);
		}
		Ok(())
	}

	/// Loads an account by account name.
	/// Must call `register_loaded_account` after loading the account.
	fn load_account(
		&self,
		account_name: impl AsRef<str>,
	) -> anyhow::Result<Arc<Mutex<SteamGuardAccount>>, ManifestAccountLoadError> {
		let entry = self.get_entry(account_name)?;
		self.load_account_by_entry(entry)
	}

	/// Loads an account from a manifest entry.
	/// Must call `register_loaded_account` after loading the account.
	fn load_account_by_entry(
		&self,
		entry: &ManifestEntry,
	) -> anyhow::Result<Arc<Mutex<SteamGuardAccount>>, ManifestAccountLoadError> {
		let path = Path::new(&self.folder).join(&entry.filename);
		let account = entry.load(
			path.as_path(),
			self.passkey.as_ref(),
			entry.encryption.as_ref(),
		)?;
		let account = Arc::new(Mutex::new(account));
		Ok(account)
	}

	/// Register an account as loaded, so it can be operated on.
	fn register_loaded_account(&mut self, account: Arc<Mutex<SteamGuardAccount>>) {
		let account_name = account.lock().unwrap().account_name.clone();
		self.accounts.insert(account_name, account);
	}

	pub fn account_exists(&self, account_name: &String) -> bool {
		for entry in &self.manifest.entries {
			if &entry.account_name == account_name {
				return true;
			}
		}
		false
	}

	pub fn add_account(&mut self, account: SteamGuardAccount) {
		debug!("adding account to manifest: {}", account.account_name);
		self.manifest.entries.push(ManifestEntry {
			filename: format!("{}.maFile", &account.account_name),
			steam_id: account.steam_id,
			account_name: account.account_name.clone(),
			encryption: None,
		});
		self.accounts
			.insert(account.account_name.clone(), Arc::new(Mutex::new(account)));
	}

	pub fn import_account(
		&mut self,
		import_path: &String,
	) -> anyhow::Result<(), ManifestAccountImportError> {
		let path = Path::new(import_path);
		if !path.exists() {
			return Err(ManifestAccountImportError::FileNotFound);
		}
		if !path.is_file() {
			return Err(ManifestAccountImportError::NotAFile);
		}

		let file = File::open(path)?;
		let reader = BufReader::new(file);
		let mut deser = serde_json::Deserializer::from_reader(reader);
		let account: SteamGuardAccount = serde_path_to_error::deserialize(&mut deser)?;
		if self.account_exists(&account.account_name) {
			return Err(ManifestAccountImportError::AlreadyExists {
				account_name: account.account_name,
			});
		}
		self.add_account(account);

		Ok(())
	}

	pub fn remove_account(&mut self, account_name: String) {
		let index = self
			.manifest
			.entries
			.iter()
			.position(|a| a.account_name == account_name)
			.unwrap();
		self.accounts.remove(&account_name);
		self.manifest.entries.remove(index);
	}

	/// Saves the manifest and all loaded accounts.
	pub fn save(&self) -> anyhow::Result<()> {
		info!("Saving manifest and accounts...");
		let save_results: Vec<_> = self
			.accounts
			.values()
			.par_bridge()
			.map(|account| -> anyhow::Result<()> {
				let account = account.lock().unwrap();
				let entry = self.get_entry(&account.account_name)?.clone();
				debug!("saving {}", entry.filename);
				let serialized = serde_json::to_vec(&account.clone())?;
				ensure!(
					serialized.len() > 2,
					"Something extra weird happened and the account was serialized into nothing."
				);

				let final_buffer: Vec<u8> = match (&self.passkey, entry.encryption.as_ref()) {
					(Some(passkey), Some(scheme)) => {
						scheme.encrypt(passkey.expose_secret(), serialized)?
					}
					(None, Some(_)) => {
						bail!("maFiles are encrypted, but no passkey was provided.");
					}
					(_, None) => serialized,
				};

				let path = Path::new(&self.folder).join(&entry.filename);
				let mut file = File::create(path)?;
				file.write_all(final_buffer.as_slice())?;
				file.sync_data()?;

				Ok(())
			})
			.collect();
		for result in save_results {
			result?;
		}
		debug!("saving manifest");
		let manifest_serialized = serde_json::to_string(&self.manifest)?;
		let path = Path::new(&self.folder).join("manifest.json");
		let mut file = File::create(path)?;
		file.write_all(manifest_serialized.as_bytes())?;
		file.sync_data()?;
		Ok(())
	}

	/// Return all loaded accounts. Order is not guarenteed.
	#[allow(dead_code)]
	pub fn get_all_loaded(&self) -> Vec<Arc<Mutex<SteamGuardAccount>>> {
		return self.accounts.values().cloned().collect();
	}

	#[allow(dead_code)]
	pub fn get_entry(
		&self,
		account_name: impl AsRef<str>,
	) -> anyhow::Result<&ManifestEntry, ManifestAccountLoadError> {
		self.manifest
			.entries
			.iter()
			.find(|e| e.account_name == account_name.as_ref())
			.ok_or(ManifestAccountLoadError::MissingManifestEntry)
	}

	#[allow(dead_code)]
	pub fn get_entry_mut(
		&mut self,
		account_name: impl AsRef<str>,
	) -> anyhow::Result<&mut ManifestEntry, ManifestAccountLoadError> {
		self.manifest
			.entries
			.iter_mut()
			.find(|e| e.account_name == account_name.as_ref())
			.ok_or(ManifestAccountLoadError::MissingManifestEntry)
	}

	pub fn has_passkey(&self) -> bool {
		self.passkey.is_some()
	}

	/// Gets the specified account by name.
	/// Fails if the account does not exist in the manifest entries.
	pub fn get_account(
		&self,
		account_name: impl AsRef<str>,
	) -> anyhow::Result<Arc<Mutex<SteamGuardAccount>>> {
		let account = self
			.accounts
			.get(account_name.as_ref())
			.cloned()
			.ok_or(anyhow!("Account not loaded"));
		account
	}

	/// Get or load the spcified account.
	pub fn get_or_load_account(
		&mut self,
		account_name: impl AsRef<str>,
	) -> anyhow::Result<Arc<Mutex<SteamGuardAccount>>, ManifestAccountLoadError> {
		let account = self.get_account(account_name.as_ref());
		if let Ok(account) = account {
			return Ok(account);
		}
		let account = self.load_account(account_name.as_ref())?;
		self.register_loaded_account(account.clone());
		Ok(account)
	}

	/// Determine if any manifest entries are missing `account_name`.
	fn is_missing_account_name(&self) -> bool {
		self.manifest
			.entries
			.iter()
			.any(|e| e.account_name.is_empty())
	}

	fn has_any_uppercase_in_account_names(&self) -> bool {
		self.manifest
			.entries
			.iter()
			.any(|e| e.account_name != e.account_name.to_lowercase())
	}

	/// Performs auto-upgrades on the manifest. Returns true if any upgrades were performed.
	pub fn auto_upgrade(&mut self) -> anyhow::Result<bool, ManifestAccountLoadError> {
		debug!("Performing auto-upgrade...");
		let mut upgraded = false;
		if self.is_missing_account_name() {
			debug!("Adding missing account names");
			for i in 0..self.manifest.entries.len() {
				let account = self.load_account_by_entry(&self.manifest.entries[i].clone())?;
				self.manifest.entries[i].account_name =
					account.lock().unwrap().account_name.clone();
			}
			upgraded = true;
		}

		if self.has_any_uppercase_in_account_names() {
			debug!("Lowercasing account names");
			for i in 0..self.manifest.entries.len() {
				self.manifest.entries[i].account_name =
					self.manifest.entries[i].account_name.to_lowercase();
			}
			upgraded = true;
		}

		Ok(upgraded)
	}

	pub fn iter(&self) -> impl Iterator<Item = &ManifestEntry> {
		self.manifest.entries.iter()
	}

	pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut ManifestEntry> {
		self.manifest.entries.iter_mut()
	}
}

trait EntryLoader<T> {
	fn load(
		&self,
		path: &Path,
		passkey: Option<&SecretString>,
		encryption_params: Option<&EncryptionScheme>,
	) -> anyhow::Result<T, ManifestAccountLoadError>;
}

impl EntryLoader<SteamGuardAccount> for ManifestEntry {
	fn load(
		&self,
		path: &Path,
		passkey: Option<&SecretString>,
		encryption_params: Option<&EncryptionScheme>,
	) -> anyhow::Result<SteamGuardAccount, ManifestAccountLoadError> {
		debug!("loading entry: {:?}", path);
		let file = File::open(path)?;
		let mut reader = BufReader::new(file);
		let account: SteamGuardAccount = match (&passkey, encryption_params.as_ref()) {
			(Some(passkey), Some(scheme)) => {
				let mut ciphertext: Vec<u8> = vec![];
				reader.read_to_end(&mut ciphertext)?;
				let plaintext = scheme.decrypt(passkey.expose_secret(), ciphertext)?;
				if plaintext[0] != b'{' && plaintext[plaintext.len() - 1] != b'}' {
					return Err(ManifestAccountLoadError::IncorrectPasskey);
				}
				let s = std::str::from_utf8(&plaintext).unwrap();
				let mut deser = serde_json::Deserializer::from_str(s);
				serde_path_to_error::deserialize(&mut deser)?
			}
			(None, Some(_)) => {
				return Err(ManifestAccountLoadError::MissingPasskey);
			}
			(_, None) => {
				let mut deser = serde_json::Deserializer::from_reader(reader);
				serde_path_to_error::deserialize(&mut deser)?
			}
		};
		Ok(account)
	}
}

#[derive(Debug, Error)]
pub enum ManifestLoadError {
	#[error("Could not find manifest.json in the specified directory.")]
	Missing(#[from] std::io::Error),
	#[error("Manifest needs to be migrated to the latest format.")]
	MigrationNeeded,
	#[error("Failed to deserialize the manifest. {self:?}")]
	DeserializationFailed(#[from] serde_path_to_error::Error<serde_json::Error>),
	#[error(transparent)]
	Unknown(#[from] anyhow::Error),
}

#[derive(Debug, Error)]
pub enum ManifestAccountLoadError {
	#[error("Could not find an entry in the manifest for this account. Check your spelling.")]
	MissingManifestEntry,
	#[error("Manifest accounts are encrypted, but no passkey was provided.")]
	MissingPasskey,
	#[error("Incorrect passkey provided.")]
	IncorrectPasskey,
	#[error("Failed to decrypt account. {self:?}")]
	DecryptionFailed(#[from] crate::encryption::EntryEncryptionError),
	#[error("Failed to deserialize the account. {self:?}")]
	DeserializationFailed(#[from] serde_path_to_error::Error<serde_json::Error>),
	#[error(transparent)]
	Unknown(#[from] anyhow::Error),
}

impl From<base64::DecodeError> for ManifestAccountLoadError {
	fn from(error: base64::DecodeError) -> Self {
		Self::Unknown(anyhow::Error::from(error))
	}
}
impl From<std::io::Error> for ManifestAccountLoadError {
	fn from(error: std::io::Error) -> Self {
		Self::Unknown(anyhow::Error::from(error))
	}
}

#[derive(Debug, Error)]
pub enum ManifestAccountImportError {
	#[error("Could not find the specified file.")]
	FileNotFound,
	#[error("The specified path is not a file.")]
	NotAFile,
	#[error(
		"The account you are trying to import, \"{account_name}\", already exists in the manifest."
	)]
	AlreadyExists { account_name: String },
	#[error(transparent)]
	IOError(#[from] std::io::Error),
	#[error("Failed to deserialize the account. {self:?}")]
	DeserializationFailed(#[from] serde_path_to_error::Error<serde_json::Error>),
	#[error(transparent)]
	Unknown(#[from] anyhow::Error),
}

#[cfg(test)]
mod tests {
	use super::*;
	use steamguard::ExposeSecret;
	use tempdir::TempDir;

	#[test]
	fn test_should_save_new_manifest() {
		let tmp_dir = TempDir::new("steamguard-cli-test").unwrap();
		let manifest_path = tmp_dir.path().join("manifest.json");
		let manager = AccountManager::new(manifest_path.as_path());
		assert!(matches!(manager.save(), Ok(_)));
	}

	#[test]
	fn test_should_save_and_load_manifest() -> anyhow::Result<()> {
		let tmp_dir = TempDir::new("steamguard-cli-test")?;
		let manifest_path = tmp_dir.path().join("manifest.json");
		println!("tempdir: {}", manifest_path.display());
		let mut manager = AccountManager::new(manifest_path.as_path());
		let mut account = SteamGuardAccount::new();
		account.account_name = "asdf1234".into();
		account.revocation_code = String::from("R12345").into();
		account.shared_secret = steamguard::token::TwoFactorSecret::parse_shared_secret(
			"zvIayp3JPvtvX/QGHqsqKBk/44s=".into(),
		)?;
		manager.add_account(account);
		manager.save()?;

		let mut manager = AccountManager::load(manifest_path.as_path())?;
		assert_eq!(manager.manifest.entries.len(), 1);
		assert_eq!(manager.manifest.entries[0].filename, "asdf1234.maFile");
		manager.load_accounts()?;
		assert_eq!(manager.manifest.entries.len(), manager.accounts.len());
		let account_name = "asdf1234";
		let account = manager.get_account(account_name)?;
		let account = account.lock().unwrap();
		assert_eq!(account.account_name, "asdf1234");
		assert_eq!(account.revocation_code.expose_secret(), "R12345");
		assert_eq!(
			account.shared_secret,
			steamguard::token::TwoFactorSecret::parse_shared_secret(
				"zvIayp3JPvtvX/QGHqsqKBk/44s=".into()
			)
			.unwrap(),
		);
		Ok(())
	}

	#[test]
	fn test_should_save_and_load_manifest_encrypted() -> anyhow::Result<()> {
		let passkey = Some(SecretString::new("password".into()));
		let tmp_dir = TempDir::new("steamguard-cli-test")?;
		let manifest_path = tmp_dir.path().join("manifest.json");
		let mut manager = AccountManager::new(manifest_path.as_path());
		let mut account = SteamGuardAccount::new();
		account.account_name = "asdf1234".into();
		account.revocation_code = String::from("R12345").into();
		account.shared_secret = steamguard::token::TwoFactorSecret::parse_shared_secret(
			"zvIayp3JPvtvX/QGHqsqKBk/44s=".into(),
		)?;
		manager.add_account(account);
		manager.manifest.entries[0].encryption = Some(EncryptionScheme::generate());
		manager.submit_passkey(passkey.clone());
		assert!(matches!(manager.save(), Ok(_)));

		let mut loaded_manager = AccountManager::load(manifest_path.as_path()).unwrap();
		loaded_manager.submit_passkey(passkey);
		assert_eq!(loaded_manager.manifest.entries.len(), 1);
		assert_eq!(
			loaded_manager.manifest.entries[0].filename,
			"asdf1234.maFile"
		);
		let _r = loaded_manager.load_accounts();
		if _r.is_err() {
			eprintln!("{:?}", _r);
		}
		assert!(matches!(_r, Ok(_)));
		assert_eq!(
			loaded_manager.manifest.entries.len(),
			loaded_manager.accounts.len()
		);
		let account_name = "asdf1234";
		let account = loaded_manager.get_account(account_name)?;
		let account = account.lock().unwrap();
		assert_eq!(account.account_name, "asdf1234");
		assert_eq!(account.revocation_code.expose_secret(), "R12345");
		assert_eq!(
			account.shared_secret,
			steamguard::token::TwoFactorSecret::parse_shared_secret(
				"zvIayp3JPvtvX/QGHqsqKBk/44s=".into()
			)
			.unwrap(),
		);

		Ok(())
	}

	#[test]
	fn test_should_save_and_load_manifest_encrypted_longer() -> anyhow::Result<()> {
		let passkey = Some(SecretString::new("password".into()));
		let tmp_dir = TempDir::new("steamguard-cli-test")?;
		let manifest_path = tmp_dir.path().join("manifest.json");
		let mut manager = AccountManager::new(manifest_path.as_path());
		let mut account = SteamGuardAccount::new();
		account.account_name = "asdf1234".into();
		account.revocation_code = String::from("R12345").into();
		account.shared_secret = steamguard::token::TwoFactorSecret::parse_shared_secret(
			"zvIayp3JPvtvX/QGHqsqKBk/44s=".into(),
		)
		.unwrap();
		account.uri = String::from("otpauth://;laksdjf;lkasdjf;lkasdj;flkasdjlkf;asjdlkfjslk;adjfl;kasdjf;lksdjflk;asjd;lfajs;ldkfjaslk;djf;lsakdjf;lksdj").into();
		account.token_gid = "asdf1234".into();
		manager.add_account(account);
		manager.submit_passkey(passkey.clone());
		manager.manifest.entries[0].encryption = Some(EncryptionScheme::generate());
		manager.save()?;

		let mut loaded_manager = AccountManager::load(manifest_path.as_path())?;
		loaded_manager.submit_passkey(passkey);
		assert_eq!(loaded_manager.manifest.entries.len(), 1);
		assert_eq!(
			loaded_manager.manifest.entries[0].filename,
			"asdf1234.maFile"
		);
		loaded_manager.load_accounts()?;
		assert_eq!(
			loaded_manager.manifest.entries.len(),
			loaded_manager.accounts.len()
		);
		let account_name = "asdf1234";
		let account = loaded_manager.get_account(account_name)?;
		let account = account.lock().unwrap();
		assert_eq!(account.account_name, "asdf1234");
		assert_eq!(account.revocation_code.expose_secret(), "R12345");
		assert_eq!(
			account.shared_secret,
			steamguard::token::TwoFactorSecret::parse_shared_secret(
				"zvIayp3JPvtvX/QGHqsqKBk/44s=".into()
			)
			.unwrap(),
		);

		Ok(())
	}

	#[test]
	fn test_should_import() -> anyhow::Result<()> {
		let tmp_dir = TempDir::new("steamguard-cli-test")?;
		let manifest_path = tmp_dir.path().join("manifest.json");
		let mut manager = AccountManager::new(manifest_path.as_path());
		let mut account = SteamGuardAccount::new();
		account.account_name = "asdf1234".into();
		account.revocation_code = String::from("R12345").into();
		account.shared_secret = steamguard::token::TwoFactorSecret::parse_shared_secret(
			"zvIayp3JPvtvX/QGHqsqKBk/44s=".into(),
		)
		.unwrap();
		manager.add_account(account);
		manager.save()?;
		std::fs::remove_file(&manifest_path)?;

		let mut loaded_manager = AccountManager::new(manifest_path.as_path());
		assert!(matches!(
			loaded_manager.import_account(
				&tmp_dir
					.path()
					.join("asdf1234.maFile")
					.into_os_string()
					.into_string()
					.unwrap()
			),
			Ok(_)
		));
		assert_eq!(
			loaded_manager.manifest.entries.len(),
			loaded_manager.accounts.len()
		);
		let account_name = "asdf1234";
		let account = loaded_manager.get_account(account_name)?;
		let account = account.lock().unwrap();
		assert_eq!(account.account_name, "asdf1234");
		assert_eq!(account.revocation_code.expose_secret(), "R12345");
		assert_eq!(
			account.shared_secret,
			steamguard::token::TwoFactorSecret::parse_shared_secret(
				"zvIayp3JPvtvX/QGHqsqKBk/44s=".into()
			)
			.unwrap(),
		);

		Ok(())
	}

	#[test]
	fn should_load_manifest_v1() -> anyhow::Result<()> {
		#[derive(Debug)]
		struct Test {
			manifest: &'static str,
			passkey: Option<SecretString>,
		}
		let cases = vec![
			Test {
				manifest: "src/fixtures/maFiles/manifest-v1/1-account/manifest.json",
				passkey: None,
			},
			Test {
				manifest: "src/fixtures/maFiles/manifest-v1/1-account-encrypted/manifest.json",
				passkey: Some(SecretString::new("password".into())),
			},
			Test {
				manifest: "src/fixtures/maFiles/manifest-v1/2-account/manifest.json",
				passkey: None,
			},
			Test {
				manifest: "src/fixtures/maFiles/manifest-v1/missing-account-name/manifest.json",
				passkey: None,
			},
		];
		for case in cases {
			eprintln!("testing: {:?}", case);
			let mut manager = AccountManager::load(Path::new(case.manifest))?;
			manager.submit_passkey(case.passkey.clone());
			manager.load_accounts()?;
			assert_eq!(manager.manifest.version, CURRENT_MANIFEST_VERSION);
			assert_eq!(manager.manifest.entries[0].account_name, "example");
			assert_eq!(manager.manifest.entries[0].steam_id, 1234);
			let account = manager.get_account("example").unwrap();
			let account = account.lock().unwrap();
			assert_eq!(account.account_name, "example");
			assert_eq!(account.steam_id, 1234);
		}
		Ok(())
	}
}