// Copyright 2014 Citra Emulator Project / PPSSPP Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#pragma once

#include <string>
#include <vector>

#include <boost/container/flat_set.hpp>

#include "common/common_types.h"

#include "core/core.h"
#include "core/mem_map.h"

#include "core/hle/kernel/kernel.h"
#include "core/hle/result.h"

enum ThreadPriority {
    THREADPRIO_HIGHEST      = 0,    ///< Highest thread priority
    THREADPRIO_DEFAULT      = 16,   ///< Default thread priority for userland apps
    THREADPRIO_LOW          = 31,   ///< Low range of thread priority for userland apps
    THREADPRIO_LOWEST       = 63,   ///< Thread priority max checked by svcCreateThread
};

enum ThreadProcessorId {
    THREADPROCESSORID_0     = 0xFFFFFFFE,   ///< Enables core appcode
    THREADPROCESSORID_1     = 0xFFFFFFFD,   ///< Enables core syscore
    THREADPROCESSORID_ALL   = 0xFFFFFFFC,   ///< Enables both cores
};

enum ThreadStatus {
    THREADSTATUS_RUNNING        = 1,
    THREADSTATUS_READY          = 2,
    THREADSTATUS_WAIT           = 4,
    THREADSTATUS_SUSPEND        = 8,
    THREADSTATUS_DORMANT        = 16,
    THREADSTATUS_DEAD           = 32,
    THREADSTATUS_WAITSUSPEND    = THREADSTATUS_WAIT | THREADSTATUS_SUSPEND
};

namespace Kernel {

class Mutex;

class Thread final : public WaitObject {
public:
    static ResultVal<SharedPtr<Thread>> Create(std::string name, VAddr entry_point, s32 priority,
        u32 arg, s32 processor_id, VAddr stack_top, u32 stack_size);

    std::string GetName() const override { return name; }
    std::string GetTypeName() const override { return "Thread"; }

    static const HandleType HANDLE_TYPE = HandleType::Thread;
    HandleType GetHandleType() const override { return HANDLE_TYPE; }

    inline bool IsRunning() const { return (status & THREADSTATUS_RUNNING) != 0; }
    inline bool IsStopped() const { return (status & THREADSTATUS_DORMANT) != 0; }
    inline bool IsReady() const { return (status & THREADSTATUS_READY) != 0; }
    inline bool IsWaiting() const { return (status & THREADSTATUS_WAIT) != 0; }
    inline bool IsSuspended() const { return (status & THREADSTATUS_SUSPEND) != 0; }
    inline bool IsIdle() const { return idle; }

    bool ShouldWait() override;
    void Acquire() override;

    s32 GetPriority() const { return current_priority; }
    void SetPriority(s32 priority);

    u32 GetThreadId() const { return thread_id; }

    void Stop(const char* reason);
    
    /**
     * Release an acquired wait object
     * @param wait_object WaitObject to release
     */
    void ReleaseWaitObject(WaitObject* wait_object);

    /// Resumes a thread from waiting by marking it as "ready"
    void ResumeFromWait();

    /**
    * Schedules an event to wake up the specified thread after the specified delay.
    * @param nanoseconds The time this thread will be allowed to sleep for.
    */
    void WakeAfterDelay(s64 nanoseconds);

    /**
     * Sets the result after the thread awakens (from either WaitSynchronization SVC)
     * @param result Value to set to the returned result
     */
    void SetWaitSynchronizationResult(ResultCode result);

    /**
     * Sets the output parameter value after the thread awakens (from WaitSynchronizationN SVC only)
     * @param output Value to set to the output parameter
     */
    void SetWaitSynchronizationOutput(s32 output);

    Core::ThreadContext context;

    u32 thread_id;

    u32 status;
    u32 entry_point;
    u32 stack_top;
    u32 stack_size;

    s32 initial_priority;
    s32 current_priority;

    s32 processor_id;

    /// Mutexes currently held by this thread, which will be released when it exits.
    boost::container::flat_set<SharedPtr<Mutex>> held_mutexes;

    std::vector<SharedPtr<WaitObject>> wait_objects; ///< Objects that the thread is waiting on
    VAddr wait_address;     ///< If waiting on an AddressArbiter, this is the arbitration address
    bool wait_all;          ///< True if the thread is waiting on all objects before resuming
    bool wait_set_output;   ///< True if the output parameter should be set on thread wakeup

    std::string name;

    /// Whether this thread is intended to never actually be executed, i.e. always idle
    bool idle = false;

private:
    Thread();
    ~Thread() override;

    /// Handle used as userdata to reference this object when inserting into the CoreTiming queue.
    Handle callback_handle;
};

extern SharedPtr<Thread> g_main_thread;

/// Sets up the primary application thread
SharedPtr<Thread> SetupMainThread(s32 priority, u32 stack_size);

/// Reschedules to the next available thread (call after current thread is suspended)
void Reschedule();

/// Arbitrate the highest priority thread that is waiting
Thread* ArbitrateHighestPriorityThread(u32 address);

/// Arbitrate all threads currently waiting...
void ArbitrateAllThreads(u32 address);

/// Gets the current thread
Thread* GetCurrentThread();

/// Waits the current thread on a sleep
void WaitCurrentThread_Sleep();

/**
 * Waits the current thread from a WaitSynchronization call
 * @param wait_object Kernel object that we are waiting on
 * @param wait_set_output If true, set the output parameter on thread wakeup (for WaitSynchronizationN only)
 * @param wait_all If true, wait on all objects before resuming (for WaitSynchronizationN only)
 */
void WaitCurrentThread_WaitSynchronization(SharedPtr<WaitObject> wait_object, bool wait_set_output, bool wait_all);

/**
 * Waits the current thread from an ArbitrateAddress call
 * @param wait_address Arbitration address used to resume from wait
 */
void WaitCurrentThread_ArbitrateAddress(VAddr wait_address);

/**
 * Sets up the idle thread, this is a thread that is intended to never execute instructions,
 * only to advance the timing. It is scheduled when there are no other ready threads in the thread queue
 * and will try to yield on every call.
 * @returns The handle of the idle thread
 */
SharedPtr<Thread> SetupIdleThread();

/// Initialize threading
void ThreadingInit();

/// Shutdown threading
void ThreadingShutdown();

} // namespace
