// file: crates/ksp-onchain-transport-lib/src/ws_lifecycle.rs
// version: 7

/// Stable local identity assigned to one physical WebSocket session.
#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct WsSessionId(std::num::NonZeroU64);

impl WsSessionId {
    /// Creates a session identity from a non-zero local value.
    #[must_use]
    pub const fn new(value: std::num::NonZeroU64) -> Self {
        return Self(value);
    }

    /// Returns the stable local numeric value.
    #[must_use]
    pub const fn get(self) -> u64 {
        return self.0.get();
    }
}

/// Stable local identity assigned to one logical WebSocket subscription.
#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct WsSubscriptionId(std::num::NonZeroU64);

impl WsSubscriptionId {
    /// Creates a subscription identity from a non-zero local value.
    #[must_use]
    pub const fn new(value: std::num::NonZeroU64) -> Self {
        return Self(value);
    }

    /// Returns the stable local numeric value.
    #[must_use]
    pub const fn get(self) -> u64 {
        return self.0.get();
    }
}

/// Observable lifecycle state of one physical WebSocket session.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum WsSessionState {
    /// No physical connection is currently active and no connection attempt is running.
    Disconnected,
    /// The actor is establishing the physical connection.
    Connecting,
    /// The physical connection is active.
    Active,
    /// The actor is reconnecting after an unexpected physical disconnect.
    Reconnecting {
        /// One-based reconnect attempt currently in progress or waiting for backoff.
        attempt: u32,
    },
    /// Explicit shutdown has started and new subscriptions are refused.
    Closing,
    /// Explicit shutdown completed.
    Closed,
    /// The session reached a terminal failure state.
    Failed,
}

/// Observable lifecycle state of one logical WebSocket subscription.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum WsSubscriptionState {
    /// The local subscription exists but its initial subscribe request has not completed.
    Requested,
    /// The logical subscription is bound to an active remote subscription.
    Active,
    /// The logical subscription is being restored after reconnect.
    Resubscribing,
    /// Local cancellation has won and remote cleanup is in progress when possible.
    Cancelling,
    /// The logical subscription reached a non-error terminal state.
    Closed,
    /// The logical subscription reached a terminal failure state.
    Failed,
}

/// WebSocket subscription family represented by one logical subscription.
#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
#[non_exhaustive]
pub enum WsSubscriptionKind {
    /// `accountSubscribe` family.
    Account,
    /// `blockSubscribe` family.
    Block,
    /// `logsSubscribe` family.
    Logs,
    /// `programSubscribe` family.
    Program,
    /// `rootSubscribe` family.
    Root,
    /// `signatureSubscribe` family.
    Signature,
    /// `slotSubscribe` family.
    Slot,
    /// `slotsUpdatesSubscribe` family.
    SlotsUpdates,
    /// `voteSubscribe` family.
    Vote,
    /// Helius LaserStream WebSocket `transactionSubscribe` extension family.
    HeliusTransaction,
}

impl WsSubscriptionKind {
    /// Returns the stable KSP descriptor for this WebSocket subscription family.
    #[must_use]
    pub const fn as_str(self) -> &'static str {
        return match self {
            Self::Account => "account",
            Self::Block => "block",
            Self::Logs => "logs",
            Self::Program => "program",
            Self::Root => "root",
            Self::Signature => "signature",
            Self::Slot => "slot",
            Self::SlotsUpdates => "slots_updates",
            Self::Vote => "vote",
            Self::HeliusTransaction => "helius_transaction",
        };
    }

    /// Returns the exact subscribe JSON-RPC method for this family.
    pub(crate) const fn subscribe_method(self) -> &'static str {
        return match self {
            Self::Account => "accountSubscribe",
            Self::Block => "blockSubscribe",
            Self::Logs => "logsSubscribe",
            Self::Program => "programSubscribe",
            Self::Root => "rootSubscribe",
            Self::Signature => "signatureSubscribe",
            Self::Slot => "slotSubscribe",
            Self::SlotsUpdates => "slotsUpdatesSubscribe",
            Self::Vote => "voteSubscribe",
            Self::HeliusTransaction => "transactionSubscribe",
        };
    }

    /// Returns the exact unsubscribe JSON-RPC method for this family.
    pub(crate) const fn unsubscribe_method(self) -> &'static str {
        return match self {
            Self::Account => "accountUnsubscribe",
            Self::Block => "blockUnsubscribe",
            Self::Logs => "logsUnsubscribe",
            Self::Program => "programUnsubscribe",
            Self::Root => "rootUnsubscribe",
            Self::Signature => "signatureUnsubscribe",
            Self::Slot => "slotUnsubscribe",
            Self::SlotsUpdates => "slotsUpdatesUnsubscribe",
            Self::Vote => "voteUnsubscribe",
            Self::HeliusTransaction => "transactionUnsubscribe",
        };
    }

    /// Returns the exact notification method emitted for this family.
    pub(crate) const fn notification_method(self) -> &'static str {
        return match self {
            Self::Account => "accountNotification",
            Self::Block => "blockNotification",
            Self::Logs => "logsNotification",
            Self::Program => "programNotification",
            Self::Root => "rootNotification",
            Self::Signature => "signatureNotification",
            Self::Slot => "slotNotification",
            Self::SlotsUpdates => "slotsUpdatesNotification",
            Self::Vote => "voteNotification",
            Self::HeliusTransaction => "transactionNotification",
        };
    }

    /// Returns whether Solana documents this standard subscription family as unstable.
    ///
    /// Provider extensions are stable here unless explicitly classified otherwise.
    pub(crate) const fn is_unstable(self) -> bool {
        return matches!(self, Self::Block | Self::SlotsUpdates | Self::Vote);
    }

    /// Emits the centralized KSP warning required before opening an unstable standard subscription.
    pub(crate) fn warn_if_unstable(self) {
        if self.is_unstable() {
            ksp_logging_lib::warn!(
                target: crate::TRACING_TARGET,
                rpc_method = self.subscribe_method(),
                subscription_kind = self.as_str(),
                documentation_status = "unstable",
                "unstable Solana WebSocket subscription requested"
            );
        }
        return;
    }
}

/// Safe lifecycle projection for one logical WebSocket subscription.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct WsSubscriptionSnapshot {
    id: crate::WsSubscriptionId,
    kind: crate::WsSubscriptionKind,
    state: crate::WsSubscriptionState,
    remote_bound: bool,
    terminal_error_code: std::option::Option<ksp_core_lib::ErrorCode>,
}

impl WsSubscriptionSnapshot {
    /// Creates one safe subscription lifecycle projection for Transport runtime internals.
    #[must_use]
    pub(crate) const fn new(
        id: crate::WsSubscriptionId,
        kind: crate::WsSubscriptionKind,
        state: crate::WsSubscriptionState,
        remote_bound: bool,
        terminal_error_code: std::option::Option<ksp_core_lib::ErrorCode>,
    ) -> Self {
        return Self { id, kind, state, remote_bound, terminal_error_code };
    }

    /// Returns the stable local subscription identity.
    #[must_use]
    pub const fn id(&self) -> crate::WsSubscriptionId {
        return self.id;
    }

    /// Returns the logical WebSocket subscription family.
    #[must_use]
    pub const fn kind(&self) -> crate::WsSubscriptionKind {
        return self.kind;
    }

    /// Returns the current logical lifecycle state.
    #[must_use]
    pub const fn state(&self) -> crate::WsSubscriptionState {
        return self.state;
    }

    /// Returns whether a current remote subscription ID is bound internally.
    ///
    /// The remote ID itself is deliberately absent because it is ephemeral across reconnects.
    #[must_use]
    pub const fn remote_bound(&self) -> bool {
        return self.remote_bound;
    }

    /// Returns the safe terminal error code when this subscription ended because of a failure.
    #[must_use]
    pub const fn terminal_error_code(&self) -> std::option::Option<ksp_core_lib::ErrorCode> {
        return self.terminal_error_code;
    }
}

/// Safe runtime snapshot for one physical WebSocket session.
///
/// The snapshot deliberately contains logical endpoint metadata and local identities only. It never stores the endpoint URL, credentials, request payloads or
/// raw notifications.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct WsSessionSnapshot {
    id: crate::WsSessionId,
    endpoint_name: std::string::String,
    provider: crate::WsProviderName,
    cluster: crate::WsClusterName,
    protocol: crate::WsProtocolKind,
    state: crate::WsSessionState,
    pending_request_count: usize,
    continuity_gap_count: u64,
    overflow_count: u64,
    subscriptions: std::vec::Vec<crate::WsSubscriptionSnapshot>,
}

impl WsSessionSnapshot {
    /// Creates one safe session projection for Transport runtime internals.
    #[must_use]
    #[allow(clippy::too_many_arguments)]
    pub(crate) fn new(
        id: crate::WsSessionId,
        endpoint_name: impl std::convert::Into<std::string::String>,
        provider: crate::WsProviderName,
        cluster: crate::WsClusterName,
        protocol: crate::WsProtocolKind,
        state: crate::WsSessionState,
        pending_request_count: usize,
        continuity_gap_count: u64,
        overflow_count: u64,
        subscriptions: std::vec::Vec<crate::WsSubscriptionSnapshot>,
    ) -> Self {
        return Self {
            id,
            endpoint_name: endpoint_name.into(),
            provider,
            cluster,
            protocol,
            state,
            pending_request_count,
            continuity_gap_count,
            overflow_count,
            subscriptions,
        };
    }

    /// Returns the stable local session identity.
    #[must_use]
    pub const fn id(&self) -> crate::WsSessionId {
        return self.id;
    }

    /// Returns the safe logical endpoint name.
    #[must_use]
    pub fn endpoint_name(&self) -> &str {
        return self.endpoint_name.as_str();
    }

    /// Returns the provider descriptor without endpoint credentials.
    #[must_use]
    pub const fn provider(&self) -> &crate::WsProviderName {
        return &self.provider;
    }

    /// Returns the cluster descriptor.
    #[must_use]
    pub const fn cluster(&self) -> &crate::WsClusterName {
        return &self.cluster;
    }

    /// Returns the WebSocket protocol family.
    #[must_use]
    pub const fn protocol(&self) -> crate::WsProtocolKind {
        return self.protocol;
    }

    /// Returns the current physical session lifecycle state.
    #[must_use]
    pub const fn state(&self) -> crate::WsSessionState {
        return self.state;
    }

    /// Returns the number of JSON-RPC requests currently awaiting responses.
    #[must_use]
    pub const fn pending_request_count(&self) -> usize {
        return self.pending_request_count;
    }

    /// Returns the number of observed physical continuity gaps for this session.
    #[must_use]
    pub const fn continuity_gap_count(&self) -> u64 {
        return self.continuity_gap_count;
    }

    /// Returns the cumulative number of notification queue overflows observed by this session.
    #[must_use]
    pub const fn overflow_count(&self) -> u64 {
        return self.overflow_count;
    }

    /// Returns safe lifecycle projections for logical subscriptions owned by this session.
    #[must_use]
    pub fn subscriptions(&self) -> &[crate::WsSubscriptionSnapshot] {
        return self.subscriptions.as_slice();
    }

    /// Returns the number of logical subscriptions currently projected by the session.
    #[must_use]
    pub fn subscription_count(&self) -> usize {
        return self.subscriptions.len();
    }
}

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