//! Storage-owned service boundary for the Iced desktop presentation adapter.

use std::{error::Error, fmt, path::Path};

use crate::{
    authentication::{NativeAuthenticationHandle, NativeAuthenticationSession},
    config::Config,
    crypto::{KeyInfo, KeyStore, SecretProvider},
    document::{DocumentError, EntryDocument, EntryDocumentService},
    git::{AutomaticEntryCommitter, GitIdentity},
    presentation::ClipboardTimeout,
    read::{TreeModel, VaultReader},
    repository::{DirectoryPath, Repository},
    secret_store::SecretProtectionPolicy,
    write::{WriteError, WriteOutcome},
};

#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum DesktopErrorKind {
    Configuration,
    Authentication,
    KeyMaterial,
    Repository,
    Read,
    Document,
    Git,
    Conflict,
    Unchanged,
    MissingDefaultKey,
}

#[derive(Debug)]
pub struct DesktopError {
    kind: DesktopErrorKind,
    message: String,
}

impl DesktopError {
    pub fn kind(&self) -> DesktopErrorKind {
        self.kind
    }

    fn new(kind: DesktopErrorKind, error: impl fmt::Display) -> Self {
        Self {
            kind,
            message: error.to_string(),
        }
    }

    fn document(error: DocumentError) -> Self {
        let kind = match &error {
            DocumentError::Write(WriteError::ConcurrentModification { .. }) => {
                DesktopErrorKind::Conflict
            }
            DocumentError::Write(WriteError::Unchanged) => DesktopErrorKind::Unchanged,
            _ => DesktopErrorKind::Document,
        };
        Self::new(kind, error)
    }
}

impl fmt::Display for DesktopError {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        formatter.write_str(&self.message)
    }
}

impl Error for DesktopError {}

#[derive(Clone, Debug)]
pub struct DesktopStorage {
    config: Config,
}

impl DesktopStorage {
    pub fn load(explicit: Option<&Path>) -> Result<Self, DesktopError> {
        Config::load(explicit)
            .map(|config| Self { config })
            .map_err(|error| DesktopError::new(DesktopErrorKind::Configuration, error))
    }

    pub fn system() -> Result<DesktopBootstrap, DesktopError> {
        let storage = Self::load(None)?;
        let keys = KeyStore::load(storage.config.key_material())
            .map_err(|error| DesktopError::new(DesktopErrorKind::KeyMaterial, error))?;
        let handle = keys
            .resolve(storage.config.default_key().as_str())
            .map_err(|error| DesktopError::new(DesktopErrorKind::KeyMaterial, error))?;
        let key = keys
            .infos()
            .find(|key| key.fingerprint() == handle.fingerprint())
            .ok_or_else(|| {
                DesktopError::new(
                    DesktopErrorKind::MissingDefaultKey,
                    "the configured GPG key is unavailable",
                )
            })?;
        let authentication = NativeAuthenticationSession::system(
            SecretProtectionPolicy::default(),
            storage.config.authentication_timeout(),
        )
        .map_err(|error| DesktopError::new(DesktopErrorKind::Authentication, error))?;
        Ok(DesktopBootstrap {
            storage,
            authentication,
            key,
        })
    }

    pub fn clipboard_timeout(&self) -> ClipboardTimeout {
        self.config.clipboard_timeout()
    }

    pub fn tree(&self) -> Result<TreeModel, DesktopError> {
        let repository = self.repository()?;
        let keys = self.keys()?;
        VaultReader::new(&repository, &keys)
            .list(&DirectoryPath::root())
            .map_err(|error| DesktopError::new(DesktopErrorKind::Read, error))
    }

    pub fn open_document(
        &self,
        entry: &str,
        secrets: &mut impl SecretProvider,
    ) -> Result<EntryDocument, DesktopError> {
        let repository = self.repository()?;
        let keys = self.keys()?;
        EntryDocumentService::new(&repository, &keys)
            .open(entry, secrets)
            .map_err(DesktopError::document)
    }

    pub fn save_document(&self, document: &EntryDocument) -> Result<WriteOutcome, DesktopError> {
        let repository = self.repository()?;
        let keys = self.keys()?;
        let entry = document.path().to_string();
        let mut committer =
            AutomaticEntryCommitter::for_entry(&repository, &entry, GitIdentity::ironstorage())
                .map_err(|error| DesktopError::new(DesktopErrorKind::Git, error))?;
        EntryDocumentService::new(&repository, &keys)
            .save_recoverable(document, None, &mut committer)
            .map_err(DesktopError::document)
    }

    pub fn save_active_document(
        &self,
        handle: &NativeAuthenticationHandle,
        document: &EntryDocument,
    ) -> Result<WriteOutcome, DesktopError> {
        handle
            .ensure_active()
            .map_err(|error| DesktopError::new(DesktopErrorKind::Authentication, error))?;
        self.save_document(document)
    }

    fn repository(&self) -> Result<Repository, DesktopError> {
        Repository::open(self.config.vault())
            .map_err(|error| DesktopError::new(DesktopErrorKind::Repository, error))
    }

    fn keys(&self) -> Result<KeyStore, DesktopError> {
        KeyStore::load(self.config.key_material())
            .map_err(|error| DesktopError::new(DesktopErrorKind::KeyMaterial, error))
    }
}

pub struct DesktopBootstrap {
    storage: DesktopStorage,
    authentication: NativeAuthenticationSession,
    key: KeyInfo,
}

impl DesktopBootstrap {
    pub fn into_parts(self) -> (DesktopStorage, NativeAuthenticationSession, KeyInfo) {
        (self.storage, self.authentication, self.key)
    }
}