// Copyright 2024 RustFS Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::error::{Error, Result};
use manager::IamCache;
use oidc::OidcSys;
use rustfs_ecstore::store::ECStore;
use std::sync::{Arc, OnceLock};
use store::object::ObjectStore;
use sys::IamSys;
use tracing::{debug, error, info, instrument, warn};

const LOG_COMPONENT_IAM: &str = "iam";
const LOG_SUBSYSTEM_RUNTIME: &str = "runtime";
const LOG_SUBSYSTEM_OIDC: &str = "oidc";
const EVENT_IAM_STATE: &str = "iam_state";
const EVENT_OIDC_STATE: &str = "oidc_state";

pub mod cache;
pub mod error;
pub mod keyring;
pub mod manager;
pub mod oidc;
pub mod oidc_state;
pub mod store;
pub mod sys;
pub mod utils;

static IAM_SYS: OnceLock<Arc<IamSys<ObjectStore>>> = OnceLock::new();
static OIDC_SYS: OnceLock<Arc<OidcSys>> = OnceLock::new();

#[instrument(skip(ecstore))]
pub async fn init_iam_sys(ecstore: Arc<ECStore>) -> Result<()> {
    if IAM_SYS.get().is_some() {
        info!(
            event = EVENT_IAM_STATE,
            component = LOG_COMPONENT_IAM,
            subsystem = LOG_SUBSYSTEM_RUNTIME,
            state = "already_initialized",
            "IAM runtime already initialized"
        );
        return Ok(());
    }

    info!(
        event = EVENT_IAM_STATE,
        component = LOG_COMPONENT_IAM,
        subsystem = LOG_SUBSYSTEM_RUNTIME,
        state = "starting",
        "IAM runtime starting"
    );

    // 1. Create the persistent storage adapter
    let storage_adapter = ObjectStore::new(ecstore);

    // 2. Create the cache manager.
    // The `new` method now performs a blocking initial load from disk.
    let cache_manager = IamCache::new(storage_adapter).await?;

    // 3. Construct the system interface
    let iam_instance = Arc::new(IamSys::new(cache_manager));

    // 4. Securely set the global singleton
    if IAM_SYS.set(iam_instance).is_err() {
        error!(
            event = EVENT_IAM_STATE,
            component = LOG_COMPONENT_IAM,
            subsystem = LOG_SUBSYSTEM_RUNTIME,
            state = "singleton_set_failed",
            "IAM runtime singleton set failed"
        );
        return Err(Error::IamSysAlreadyInitialized);
    }

    info!(
        event = EVENT_IAM_STATE,
        component = LOG_COMPONENT_IAM,
        subsystem = LOG_SUBSYSTEM_RUNTIME,
        state = "ready",
        "IAM runtime ready"
    );
    Ok(())
}

#[inline]
pub fn get() -> Result<Arc<IamSys<ObjectStore>>> {
    let sys = IAM_SYS.get().map(Arc::clone).ok_or(Error::IamSysNotInitialized)?;

    // Double-check the internal readiness state. The OnceLock is only set
    // after initialization and data loading complete, so this is a defensive
    // guard to ensure callers never operate on a partially initialized system.
    if !sys.is_ready() {
        return Err(Error::IamSysNotInitialized);
    }

    Ok(sys)
}

pub fn get_global_iam_sys() -> Option<Arc<IamSys<ObjectStore>>> {
    IAM_SYS.get().cloned()
}

/// Initialize the global OIDC system. Non-fatal if no OIDC providers are configured.
pub async fn init_oidc_sys() -> Result<()> {
    if OIDC_SYS.get().is_some() {
        debug!(
            event = EVENT_OIDC_STATE,
            component = LOG_COMPONENT_IAM,
            subsystem = LOG_SUBSYSTEM_OIDC,
            state = "already_initialized",
            "OIDC runtime already initialized"
        );
        return Ok(());
    }

    debug!(
        event = EVENT_OIDC_STATE,
        component = LOG_COMPONENT_IAM,
        subsystem = LOG_SUBSYSTEM_OIDC,
        state = "starting",
        "OIDC runtime starting"
    );

    let oidc_sys = match OidcSys::new().await {
        Ok(sys) => {
            if sys.has_providers() {
                debug!(
                    event = EVENT_OIDC_STATE,
                    component = LOG_COMPONENT_IAM,
                    subsystem = LOG_SUBSYSTEM_OIDC,
                    provider_count = sys.list_providers().len(),
                    state = "ready",
                    "OIDC runtime ready"
                );
            } else {
                debug!(
                    event = EVENT_OIDC_STATE,
                    component = LOG_COMPONENT_IAM,
                    subsystem = LOG_SUBSYSTEM_OIDC,
                    state = "empty",
                    "OIDC runtime has no providers"
                );
            }
            sys
        }
        Err(e) => {
            warn!(
                event = EVENT_OIDC_STATE,
                component = LOG_COMPONENT_IAM,
                subsystem = LOG_SUBSYSTEM_OIDC,
                state = "init_failed_non_fatal",
                error = %e,
                "OIDC runtime initialization failed"
            );
            OidcSys::empty().map_err(Error::StringError)?
        }
    };

    if OIDC_SYS.set(Arc::new(oidc_sys)).is_err() {
        warn!(
            event = EVENT_OIDC_STATE,
            component = LOG_COMPONENT_IAM,
            subsystem = LOG_SUBSYSTEM_OIDC,
            state = "singleton_set_race",
            "OIDC runtime singleton set raced"
        );
    }

    Ok(())
}

/// Get the global OIDC system.
pub fn get_oidc() -> Option<Arc<OidcSys>> {
    OIDC_SYS.get().cloned()
}