// Copyright (c) 2023-present The Bitcoin Core developers

// Distributed under the MIT software license, see the accompanying

// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_NODE_KERNEL_NOTIFICATIONS_H

#define BITCOIN_NODE_KERNEL_NOTIFICATIONS_H

#include <kernel/notifications_interface.h>

#include <sync.h>

#include <uint256.h>

#include <atomic>

#include <cstdint>

#include <functional>

class ArgsManager;

class CBlockIndex;

enum class SynchronizationState;

struct bilingual_str;

namespace kernel {

enum class Warning;

} // namespace kernel

namespace node {

class Warnings;

static constexpr int DEFAULT_STOPATHEIGHT{0};

//! State tracked by the KernelNotifications interface meant to be used by

//! mining code, index code, RPCs, and other code sitting above the validation

//! layer.

//!

//! Currently just tracks the chain tip, but could be used to hold other

//! information in the future, like the last flushed block, pruning

//! information, etc.

struct KernelState {

    bool chainstate_loaded{false};

    std::optional<uint256> tip_block;

};

class KernelNotifications : public kernel::Notifications

{

public:

    KernelNotifications(const std::function<bool()>& shutdown_request, std::atomic<int>& exit_status, node::Warnings& warnings)

        : m_shutdown_request(shutdown_request), m_exit_status{exit_status}, m_warnings{warnings} {}

    [[nodiscard]] kernel::InterruptResult blockTip(SynchronizationState state, const CBlockIndex& index, double verification_progress) override EXCLUSIVE_LOCKS_REQUIRED(!m_tip_block_mutex);

    void headerTip(SynchronizationState state, int64_t height, int64_t timestamp, bool presync) override;

    void progress(const bilingual_str& title, int progress_percent, bool resume_possible) override;

    void warningSet(kernel::Warning id, const bilingual_str& message) override;

    void warningUnset(kernel::Warning id) override;

    void flushError(const bilingual_str& message) override;

    void fatalError(const bilingual_str& message) override;

    void setChainstateLoaded(bool chainstate_loaded) EXCLUSIVE_LOCKS_REQUIRED(!m_tip_block_mutex) {

        LOCK(m_tip_block_mutex);

        if (!chainstate_loaded) m_state = {};

        m_state.chainstate_loaded = chainstate_loaded;

        m_tip_block_cv.notify_all();

    }

    //! Block height after which blockTip notification will return Interrupted{}, if >0.

    int m_stop_at_height{DEFAULT_STOPATHEIGHT};

    //! Useful for tests, can be set to false to avoid shutdown on fatal error.

    bool m_shutdown_on_fatal_error{true};

    Mutex m_tip_block_mutex;

    std::condition_variable m_tip_block_cv GUARDED_BY(m_tip_block_mutex);

    KernelState m_state GUARDED_BY(m_tip_block_mutex);

    //! The block for which the last blockTip notification was received.

    //! It's first set when the tip is connected during node initialization.

    //! Might be unset during an early shutdown.

    std::optional<uint256> TipBlock() EXCLUSIVE_LOCKS_REQUIRED(m_tip_block_mutex);

private:

    const std::function<bool()>& m_shutdown_request;

    std::atomic<int>& m_exit_status;

    node::Warnings& m_warnings;

};

void ReadNotificationArgs(const ArgsManager& args, KernelNotifications& notifications);

} // namespace node

#endif // BITCOIN_NODE_KERNEL_NOTIFICATIONS_H