// file: crates/ksp-app-wallet-desk/src/wallet_import.rs
// version: 3

//! Native-picker transfer import staging with bounded secret material kept only in Rust.

use tokio::io::AsyncReadExt; // rust-rules: trait-import
use ts_rs::TS; // rust-rules: trait-import

/// Request that chooses only the transfer format; the source path comes from the native Rust picker.
#[derive(serde::Deserialize, TS)]
#[serde(rename_all = "camelCase")]
#[ts(export, export_to = "../frontend/ts/bindings/ksp_app_wallet_desk/wallet_import/WalletImportSourceRequestDto.ts")]
pub(crate) struct WalletImportSourceRequestDto {
    /// Transfer encoding expected for the selected external file.
    pub(crate) format: crate::WalletTransferFormatDto,
}

/// Safe projection returned after validating one native-picker import source.
#[derive(Clone, serde::Serialize, TS)]
#[serde(rename_all = "camelCase")]
#[ts(export, export_to = "../frontend/ts/bindings/ksp_app_wallet_desk/wallet_import/WalletTransferInspectionDto.ts")]
pub(crate) struct WalletTransferInspectionDto {
    /// Transfer format used to validate the secret source.
    pub(crate) format: crate::WalletTransferFormatDto,
    /// Public identity derived from the imported keypair.
    pub(crate) pubkey: String,
    /// Basename only; no parent path is ever projected.
    pub(crate) source_name: String,
}

/// Import request whose new native Wallet credentials move frontend -> Rust only.
#[derive(serde::Deserialize, TS)]
#[serde(rename_all = "camelCase")]
#[ts(export, export_to = "../frontend/ts/bindings/ksp_app_wallet_desk/wallet_import/WalletImportRequestDto.ts")]
pub(crate) struct WalletImportRequestDto {
    /// Optional protected internal alias stored in the new native Wallet.
    pub(crate) alias: std::option::Option<String>,
    /// Root-scoped destination filename under the effective Wallet directory.
    pub(crate) filename: String,
    /// Optional first protected note stored in the imported Wallet.
    pub(crate) initial_note: std::option::Option<String>,
    /// New OWNER password transported only frontend -> Rust.
    pub(crate) owner_password: String,
    /// Optional new VIEW password; `None` keeps VIEW disabled.
    pub(crate) view_password: std::option::Option<String>,
}

/// Rust-only staged transfer source. Secret bytes are bounded and zeroized on drop.
pub(crate) struct PendingWalletImport {
    bytes: zeroize::Zeroizing<std::vec::Vec<u8>>,
    format: crate::WalletTransferFormatDto,
    inspection: WalletTransferInspectionDto,
}

impl PendingWalletImport {
    /// Returns the safe inspection projection without exposing source bytes or path.
    #[must_use]
    pub(crate) fn safe_projection(&self) -> WalletTransferInspectionDto {
        return self.inspection.clone();
    }

    /// Returns the bounded secret transfer bytes for one immediate Wallet import operation.
    #[must_use]
    pub(crate) fn source_bytes(&self) -> &[u8] {
        return self.bytes.as_slice();
    }

    /// Returns the stable Wallet transfer format corresponding to the staged source.
    #[must_use]
    pub(crate) const fn wallet_format(&self) -> ksp_wallet_lib::WalletTransferFormat {
        return self.format.wallet_format();
    }
}

/// Reads, bounds and validates one native-picker transfer source while retaining no external path.
pub(crate) async fn stage_wallet_import_source(
    source: std::path::PathBuf,
    format: crate::WalletTransferFormatDto,
) -> ksp_core_lib::Result<PendingWalletImport> {
    let metadata = tokio::fs::symlink_metadata(source.as_path()).await;
    let metadata = match metadata {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => {
            return std::result::Result::Err(
                ksp_core_lib::Error::new(crate::ERROR_CODE_WALLET_IMPORT_SOURCE_INVALID, "Cannot inspect the selected Wallet transfer source")
                    .with_source(error),
            );
        },
    };
    if metadata.file_type().is_symlink() || !metadata.is_file() {
        return std::result::Result::Err(ksp_core_lib::Error::new(
            crate::ERROR_CODE_WALLET_IMPORT_SOURCE_INVALID,
            "Selected Wallet transfer source must be one regular non-symlink file",
        ));
    }
    let source_name = source.file_name().and_then(std::ffi::OsStr::to_str);
    let source_name = match source_name {
        std::option::Option::Some(value) if !value.is_empty() => value.to_owned(),
        _ => "selected-transfer".to_owned(),
    };
    let file = tokio::fs::File::open(source.as_path()).await;
    let file = match file {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => {
            return std::result::Result::Err(
                ksp_core_lib::Error::new(crate::ERROR_CODE_WALLET_IMPORT_SOURCE_INVALID, "Cannot open the selected Wallet transfer source").with_source(error),
            );
        },
    };
    let maximum_source_bytes = format.maximum_source_bytes();
    let read_limit = maximum_source_bytes.saturating_add(1);
    let read_limit = u64::try_from(read_limit);
    let read_limit = match read_limit {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => {
            return std::result::Result::Err(
                ksp_core_lib::Error::new(crate::ERROR_CODE_APP_STATE_INVALID, "Wallet transfer source bound exceeds platform range").with_source(error),
            );
        },
    };
    let mut reader = file.take(read_limit);
    let mut bytes = zeroize::Zeroizing::new(std::vec::Vec::with_capacity(maximum_source_bytes.saturating_add(1)));
    let read_result = reader.read_to_end(&mut bytes).await;
    if let std::result::Result::Err(error) = read_result {
        return std::result::Result::Err(
            ksp_core_lib::Error::new(crate::ERROR_CODE_WALLET_IMPORT_SOURCE_INVALID, "Cannot read the selected Wallet transfer source").with_source(error),
        );
    }
    if bytes.len() > maximum_source_bytes {
        return std::result::Result::Err(ksp_core_lib::Error::new(
            crate::ERROR_CODE_WALLET_IMPORT_SOURCE_INVALID,
            "Selected Wallet transfer source exceeds the supported format bound",
        ));
    }
    let inspection = ksp_wallet_lib::inspect_wallet_transfer(bytes.as_slice(), format.wallet_format());
    let inspection = match inspection {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let dto = WalletTransferInspectionDto { format, pubkey: inspection.pubkey().to_string(), source_name };
    return std::result::Result::Ok(PendingWalletImport { bytes, format, inspection: dto });
}

#[cfg(test)]
#[path = "../unit_tests/wallet_import.rs"]
mod tests;