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// ------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
// Licensed under the MIT License (MIT). See License.txt in the repo root for license information.
// ------------------------------------------------------------

// stateful contains rs definition of stateful traits that user needs to implement

use mssf_com::FabricRuntime::IFabricStatefulServicePartition;
use windows_core::{Error, HSTRING};

use crate::sync::CancellationToken;
use crate::types::{LoadMetric, LoadMetricListRef, ReplicaRole};

use super::stateful_types::{Epoch, OpenMode, ReplicaInfo, ReplicaSetConfig, ReplicaSetQuarumMode};

pub trait StatefulServiceFactory {
    fn create_replica(
        &self,
        servicetypename: &HSTRING,
        servicename: &HSTRING,
        initializationdata: &[u8],
        partitionid: &::windows::core::GUID,
        replicaid: i64,
    ) -> Result<impl StatefulServiceReplica, Error>;
}

// safe service instance
// The trait style is modeled by tonic server trait where send, sync and static are all required.
// This makes sure that bridge/proxy layer can work with rust async await easier.
#[trait_variant::make(StatefulServiceReplica: Send)]
pub trait LocalStatefulServiceReplica: Send + Sync + 'static {
    // Note that open returns PrimaryReplicator instead of Replicator.
    // The replicator that gives to SF has to implement primary replicator all the time.
    // Ideally the return type should be Result<impl PrimaryReplicator>, but in bridge impl
    // primary replicator needs to be stored in a ctx, but impl trait cannot be a variable type and anonymous.
    // We cannot use rust async trait because dynamic dispatch is not yet supported.
    async fn open(
        &self,
        openmode: OpenMode,
        partition: &StatefulServicePartition,
        cancellation_token: CancellationToken,
    ) -> windows::core::Result<impl PrimaryReplicator>;
    async fn change_role(
        &self,
        newrole: ReplicaRole,
        cancellation_token: CancellationToken,
    ) -> ::windows_core::Result<HSTRING>; // replica address
    async fn close(&self, cancellation_token: CancellationToken) -> windows::core::Result<()>;
    fn abort(&self);
}

#[derive(Debug, Clone)]
pub struct StatefulServicePartition {
    com_impl: IFabricStatefulServicePartition,
}

impl StatefulServicePartition {
    pub fn get_com(&self) -> &IFabricStatefulServicePartition {
        &self.com_impl
    }

    /// Reports load for the current replica in the partition.
    pub fn report_load(&self, metrics: &[LoadMetric]) -> crate::Result<()> {
        let metrics_ref = LoadMetricListRef::from_slice(metrics);
        let raw = metrics_ref.as_raw_slice();
        unsafe { self.com_impl.ReportLoad(raw) }
    }
}

impl From<&IFabricStatefulServicePartition> for StatefulServicePartition {
    fn from(e: &IFabricStatefulServicePartition) -> Self {
        StatefulServicePartition {
            com_impl: e.clone(),
        }
    }
}

#[trait_variant::make(Replicator: Send)]
pub trait LocalReplicator: Send + Sync + 'static {
    async fn open(&self, cancellation_token: CancellationToken) -> ::windows_core::Result<HSTRING>; // replicator address
    async fn close(&self, cancellation_token: CancellationToken) -> ::windows_core::Result<()>;
    async fn change_role(
        &self,
        epoch: &Epoch,
        role: &ReplicaRole,
        cancellation_token: CancellationToken,
    ) -> ::windows_core::Result<()>;
    async fn update_epoch(
        &self,
        epoch: &Epoch,
        cancellation_token: CancellationToken,
    ) -> ::windows_core::Result<()>;
    fn get_current_progress(&self) -> ::windows_core::Result<i64>;
    fn get_catch_up_capability(&self) -> ::windows_core::Result<i64>;
    fn abort(&self);
}

#[trait_variant::make(PrimaryReplicator: Send)]
pub trait LocalPrimaryReplicator: Replicator {
    // SF calls this to indicate that possible data loss has occurred (write quorum loss),
    // returns is isStateChanged. If true, SF will re-create other secondaries.
    // The default SF impl might be a pass through to the state provider.
    async fn on_data_loss(
        &self,
        cancellation_token: CancellationToken,
    ) -> ::windows_core::Result<u8>;
    fn update_catch_up_replica_set_configuration(
        &self,
        currentconfiguration: &ReplicaSetConfig,
        previousconfiguration: &ReplicaSetConfig,
    ) -> ::windows_core::Result<()>;
    async fn wait_for_catch_up_quorum(
        &self,
        catchupmode: ReplicaSetQuarumMode,
        cancellation_token: CancellationToken,
    ) -> ::windows_core::Result<()>;
    fn update_current_replica_set_configuration(
        &self,
        currentconfiguration: &ReplicaSetConfig,
    ) -> ::windows_core::Result<()>;
    async fn build_replica(
        &self,
        replica: &ReplicaInfo,
        cancellation_token: CancellationToken,
    ) -> ::windows_core::Result<()>;
    fn remove_replica(&self, replicaid: i64) -> ::windows_core::Result<()>;
}