// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <ddk/binding.h>
#include <ddk/device.h>
#include <ddk/driver.h>
#include <fbl/intrusive_double_list.h>
#include <fbl/string.h>
#include <fbl/unique_ptr.h>
#include <fbl/vector.h>
#include <lib/async/cpp/task.h>
#include <lib/async/cpp/wait.h>
#include <lib/async-loop/cpp/loop.h>
#include <lib/fit/function.h>
#include <lib/zx/channel.h>
#include <lib/zx/job.h>
#include <lib/zx/process.h>
#include <lib/zx/socket.h>
#include <lib/zx/vmo.h>

#include <utility>

#include "metadata.h"

namespace devmgr {

class Coordinator;
class Devhost;
class DevhostLoaderService;
struct Devnode;
class SuspendContext;

class PendingOperation {
public:
    enum struct Op : uint32_t {
        kBind = 1,
        kSuspend = 2,
    };

    PendingOperation(Op op, SuspendContext* context) : op_(op), context_(context) {}

    struct Node {
        static fbl::DoublyLinkedListNodeState<fbl::unique_ptr<PendingOperation>>& node_state(
            PendingOperation& obj) {
            return obj.node_;
        }
    };

    Op op() const { return op_; }
    SuspendContext* context() const { return context_; }

private:
    fbl::DoublyLinkedListNodeState<fbl::unique_ptr<PendingOperation>> node_;

    Op op_;
    SuspendContext* context_;
};

#define DEV_HOST_DYING 1
#define DEV_HOST_SUSPEND 2

struct Device {
    explicit Device(Coordinator* coord);
    ~Device();

    // Begins waiting in |dispatcher| on |dev->wait|.  This transfers a
    // reference of |dev| to the dispatcher.  The dispatcher returns ownership
    // when the of that reference when the handler is invoked.
    // TODO(teisenbe/kulakowski): Make this take a RefPtr
    static zx_status_t BeginWait(Device* dev, async_dispatcher_t* dispatcher) {
        // TODO(teisenbe/kulakowski): Once this takes a refptr, we should leak a
        // ref in the success case (to present the ref owned by the dispatcher).
        return dev->wait.Begin(dispatcher);
    }

    // Entrypoint for the RPC handler that captures the pointer ownership
    // semantics.
    void HandleRpcEntry(async_dispatcher_t* dispatcher, async::WaitBase* wait, zx_status_t status,
                        const zx_packet_signal_t* signal) {
        // TODO(teisenbe/kulakowski): Perform the appropriate dance to construct
        // a RefPtr from |this| without a net-increase in refcount, to represent
        // the dispatcher passing ownership of its reference to the handler
        HandleRpc(this, dispatcher, wait, status, signal);
    }

    // TODO(teisenbe/kulakowski): Make this take a RefPtr
    static void HandleRpc(Device* dev, async_dispatcher_t* dispatcher,
                          async::WaitBase* wait, zx_status_t status,
                          const zx_packet_signal_t* signal);

    Coordinator* coordinator;
    zx::channel hrpc;
    uint32_t flags = 0;

    async::WaitMethod<Device, &Device::HandleRpcEntry> wait{this};
    async::TaskClosure publish_task;

    Devhost* host = nullptr;
    const char* name = nullptr;
    const char* libname = nullptr;
    fbl::unique_ptr<const char[]> args;
    // The backoff between each driver retry. This grows exponentially.
    zx::duration backoff = zx::msec(250);
    // The number of retries left for the driver.
    uint32_t retries = 4;
    mutable int32_t refcount_ = 0;
    uint32_t protocol_id = 0;
    uint32_t prop_count = 0;
    Devnode* self = nullptr;
    Devnode* link = nullptr;
    Device* parent = nullptr;
    Device* proxy = nullptr;

    // listnode for this device in its parent's
    // list-of-children
    fbl::DoublyLinkedListNodeState<Device*> node;
    struct Node {
        static fbl::DoublyLinkedListNodeState<Device*>& node_state(
            Device& obj) {
            return obj.node;
        }
    };

    // listnode for this device in its devhost's
    // list-of-devices
    fbl::DoublyLinkedListNodeState<Device*> dhnode;
    struct DevhostNode {
        static fbl::DoublyLinkedListNodeState<Device*>& node_state(
            Device& obj) {
            return obj.dhnode;
        }
    };

    // list of all child devices of this device
    fbl::DoublyLinkedList<Device*, Node> children;

    // list of outstanding requests from the devcoord
    // to this device's devhost, awaiting a response
    fbl::DoublyLinkedList<fbl::unique_ptr<PendingOperation>, PendingOperation::Node> pending;

    // listnode for this device in the all devices list
    fbl::DoublyLinkedListNodeState<Device*> anode;
    struct AllDevicesNode {
        static fbl::DoublyLinkedListNodeState<Device*>& node_state(
            Device& obj) {
            return obj.anode;
        }
    };

    // Metadata entries associated to this device.
    fbl::DoublyLinkedList<fbl::unique_ptr<Metadata>, Metadata::Node> metadata;

    fbl::unique_ptr<zx_device_prop_t[]> props;

    // Allocation backing |name| and |libname|
    fbl::unique_ptr<char[]> name_alloc_;

    // The AddRef and Release functions follow the contract for fbl::RefPtr.
    void AddRef() const {
        ++refcount_;
    }

    // Returns true when the last reference has been released.
    bool Release() const {
        const int32_t rc = refcount_;
        --refcount_;
        return rc == 1;
    }
};

class Devhost {
public:
    struct AllDevhostsNode {
        static fbl::DoublyLinkedListNodeState<Devhost*>& node_state(
            Devhost& obj) {
            return obj.anode_;
        }
    };
    struct SuspendNode {
        static fbl::DoublyLinkedListNodeState<Devhost*>& node_state(
            Devhost& obj) {
            return obj.snode_;
        }
    };
    struct Node {
        static fbl::DoublyLinkedListNodeState<Devhost*>& node_state(
            Devhost& obj) {
            return obj.node_;
        }
    };

    Devhost();

    zx_handle_t hrpc() const { return hrpc_; }
    void set_hrpc(zx_handle_t hrpc) { hrpc_ = hrpc; }
    zx::unowned_process proc() const { return zx::unowned_process(proc_); }
    void set_proc(zx_handle_t proc) { proc_.reset(proc); }
    zx_koid_t koid() const { return koid_; }
    void set_koid(zx_koid_t koid) { koid_ = koid; }
    // Note: this is a non-const reference to make |= etc. ergonomic.
    uint32_t& flags() { return flags_; }
    Devhost* parent() const { return parent_; }
    void set_parent(Devhost* parent) { parent_ = parent; }
    fbl::DoublyLinkedList<Device*, Device::DevhostNode>& devices() { return devices_; }
    fbl::DoublyLinkedList<Devhost*, Node>& children() { return children_; }

    // The AddRef and Release functions follow the contract for fbl::RefPtr.
    void AddRef() const {
        ++refcount_;
    }

    // Returns true when the last reference has been released.
    bool Release() const {
        const int32_t rc = refcount_;
        --refcount_;
        return rc == 1;
    }

private:
    async::Wait wait_;
    zx_handle_t hrpc_;
    zx::process proc_;
    zx_koid_t koid_;
    mutable int32_t refcount_;
    uint32_t flags_;
    Devhost* parent_;

    // list of all devices on this devhost
    fbl::DoublyLinkedList<Device*, Device::DevhostNode> devices_;

    // listnode for this devhost in the all devhosts list
    fbl::DoublyLinkedListNodeState<Devhost*> anode_;

    // listnode for this devhost in the order-to-suspend list
    fbl::DoublyLinkedListNodeState<Devhost*> snode_;

    // listnode for this devhost in its parent devhost's list-of-children
    fbl::DoublyLinkedListNodeState<Devhost*> node_;

    // list of all child devhosts of this devhost
    fbl::DoublyLinkedList<Devhost*, Node> children_;
};

class SuspendContext {
public:
    enum struct Flags : uint32_t {
        kRunning = 0u,
        kSuspend = 1u,
    };

    SuspendContext() {
    }

    SuspendContext(Coordinator* coordinator,
                   Flags flags, uint32_t sflags, zx::socket socket,
                   zx::vmo kernel = zx::vmo(),
                   zx::vmo bootdata = zx::vmo()) :
        coordinator_(coordinator), flags_(flags), sflags_(sflags),
        socket_(std::move(socket)), kernel_(std::move(kernel)),
        bootdata_(std::move(bootdata)) {
    }

    ~SuspendContext() {
        devhosts_.clear();
    }

    SuspendContext(SuspendContext&&) = default;
    SuspendContext& operator=(SuspendContext&&) = default;

    Coordinator* coordinator() { return coordinator_; }

    zx_status_t status() const { return status_; }
    void set_status(zx_status_t status) { status_ = status; }
    Flags flags() const { return flags_; }
    void set_flags(Flags flags) { flags_ = flags; }
    uint32_t sflags() const { return sflags_; }

    Devhost* dh() const { return dh_; }
    void set_dh(Devhost* dh) { dh_ = dh; }

    using DevhostList = fbl::DoublyLinkedList<Devhost*, Devhost::SuspendNode>;
    DevhostList& devhosts() { return devhosts_; }
    const DevhostList& devhosts() const { return devhosts_; }

    const zx::vmo& kernel() const { return kernel_; }
    const zx::vmo& bootdata() const { return bootdata_; }

    // Close the socket whose ownership was handed to this SuspendContext.
    void CloseSocket() {
        socket_.reset();
    }

    // The AddRef and Release functions follow the contract for fbl::RefPtr.
    void AddRef() const {
        ++count_;
    }

    // Returns true when the last message reference has been released.
    bool Release() const {
        const int32_t rc = count_;
        --count_;
        return rc == 1;
    }

private:
    Coordinator* coordinator_ = nullptr;

    zx_status_t status_ = ZX_OK;
    Flags flags_ = Flags::kRunning;

    // suspend flags
    uint32_t sflags_ = 0u;
    // outstanding msgs
    mutable uint32_t count_ = 0u;
    // next devhost to process
    Devhost* dh_ = nullptr;
    fbl::DoublyLinkedList<Devhost*, Devhost::SuspendNode> devhosts_;

    // socket to notify on for 'dm reboot' and 'dm poweroff'
    zx::socket socket_;

    // mexec arguments
    zx::vmo kernel_;
    zx::vmo bootdata_;
};

// This device is never destroyed
#define DEV_CTX_IMMORTAL      0x01

// This device requires that children are created in a
// new devhost attached to a proxy device
#define DEV_CTX_MUST_ISOLATE  0x02

// This device may be bound multiple times
#define DEV_CTX_MULTI_BIND    0x04

// This device is bound and not eligible for binding
// again until unbound.  Not allowed on MULTI_BIND ctx.
#define DEV_CTX_BOUND         0x08

// Device has been remove()'d
#define DEV_CTX_DEAD          0x10

// Device has been removed but its rpc channel is not
// torn down yet.  The rpc transport will call remove
// when it notices at which point the device will leave
// the zombie state and drop the reference associated
// with the rpc channel, allowing complete destruction.
#define DEV_CTX_ZOMBIE        0x20

// Device is a proxy -- its "parent" is the device it's
// a proxy to.
#define DEV_CTX_PROXY         0x40

// Device is not visible in devfs or bindable.
// Devices may be created in this state, but may not
// return to this state once made visible.
#define DEV_CTX_INVISIBLE     0x80

struct Driver {
    Driver() = default;

    fbl::String name;
    fbl::unique_ptr<const zx_bind_inst_t[]> binding;
    // Binding size in number of bytes, not number of entries
    // TODO: Change it to number of entries
    uint32_t binding_size = 0;
    uint32_t flags = 0;
    zx::vmo dso_vmo;

    fbl::DoublyLinkedListNodeState<Driver*> node;
    struct Node {
        static fbl::DoublyLinkedListNodeState<Driver*>& node_state(
            Driver& obj) {
            return obj.node;
        }
    };

    fbl::String libname;
};

#define DRIVER_NAME_LEN_MAX 64

zx_status_t devfs_publish(Device* parent, Device* dev);
void devfs_unpublish(Device* dev);
void devfs_advertise(Device* dev);
void devfs_advertise_modified(Device* dev);

// Values parsed out of argv.  All paths described below are absolute paths.
struct DevmgrArgs {
    // Load drivers from these directories.  If this is empty, the default will
    // be used.
    fbl::Vector<const char*> driver_search_paths;
    // Load the drivers with these paths.  The specified drivers do not need to
    // be in directories in |driver_search_paths|.
    fbl::Vector<const char*> load_drivers;
    // Use this driver as the sys_device driver.  If nullptr, the default will
    // be used.
    const char* sys_device_driver = nullptr;
};

class Coordinator {
public:
    Coordinator(const Coordinator&) = delete;
    Coordinator& operator=(const Coordinator&) = delete;

    Coordinator(Coordinator&&) = delete;
    Coordinator& operator=(Coordinator&&) = delete;

    Coordinator(zx::job devhost_job, async_dispatcher_t* dispatcher, bool require_system);

    zx_status_t InitializeCoreDevices();

    zx_status_t HandleDmctlWrite(size_t len, const char* cmd);

    const Driver* LibnameToDriver(const char* libname) const;
    zx_status_t LibnameToVmo(const char* libname, zx::vmo* out_vmo) const;

    bool InSuspend() const;

    void DumpDevice(const Device* dev, size_t indent) const;
    void DumpState() const;
    void DumpDeviceProps(const Device* dev) const;
    void DumpGlobalDeviceProps() const;
    void DumpDrivers() const;

    zx_status_t GetTopoPath(const Device* dev, char* out, size_t max) const;

    zx_status_t NewDevhost(const char* name, Devhost* parent, Devhost** out);
    void ReleaseDevhost(Devhost* dh);
    void ReleaseDevice(Device* dev);

    zx_status_t AddDevice(Device* parent, zx::channel rpc, const uint64_t* props_data,
                          size_t props_count, fbl::StringPiece name, uint32_t protocol_id,
                          fbl::StringPiece driver_path, fbl::StringPiece args, bool invisible);
    zx_status_t MakeVisible(Device* dev);
    zx_status_t RemoveDevice(Device* dev, bool forced);

    zx_status_t LoadFirmware(Device* dev, const char* path, zx::vmo* vmo, size_t* size);

    zx_status_t GetMetadata(Device* dev, uint32_t type, void* buffer, size_t buflen,
                            size_t* actual);
    zx_status_t AddMetadata(Device* dev, uint32_t type, const void* data, uint32_t length);
    zx_status_t PublishMetadata(Device* dev, const char* path, uint32_t type, const void* data,
                                uint32_t length);

    zx_status_t BindDevice(Device* dev, fbl::StringPiece drvlibname);
    void BindDriver(Driver* drv);

    zx_status_t HandleDeviceRead(Device* dev);

    zx_status_t PrepareProxy(Device* dev);
    zx_status_t AttemptBind(const Driver* drv, Device* dev);

    void HandleNewDevice(Device* dev);

    void ScanSystemDrivers();
    void BindSystemDrivers();
    void BindDrivers();
    void UseFallbackDrivers();

    void Mexec(zx::vmo kernel, zx::vmo bootdata);

    void Suspend(uint32_t flags);
    void ContinueSuspend(SuspendContext* ctx);
    Devhost* BuildSuspendList(SuspendContext* ctx);

    void DriverAdded(Driver* drv, const char* version);
    void DriverAddedInit(Driver* drv, const char* version);
    void DriverAddedSys(Driver* drv, const char* version);

    async_dispatcher_t* dispatcher() const { return dispatcher_; }
    bool require_system() const { return require_system_; }

    void set_running(bool running) { running_ = running; }
    void set_loader_service(DevhostLoaderService* loader_service) {
        loader_service_ = loader_service;
    }

    fbl::DoublyLinkedList<Device*, Device::AllDevicesNode>& devices() { return devices_; }
    Device& root_device() { return root_device_; }
    Device& misc_device() { return misc_device_; }
    Device& sys_device() { return sys_device_; }
    Device& test_device() { return test_device_; }

    SuspendContext& suspend_context() { return suspend_context_; }
    bool suspend_fallback() const { return suspend_fallback_; }
    void set_suspend_fallback(bool suspend_fallback) { suspend_fallback_ = suspend_fallback; }
    bool suspend_debug() const { return suspend_debug_; }
    void set_suspend_debug(bool suspend_debug) { suspend_debug_ = suspend_debug; }

    bool system_available() const { return system_available_; }
    void set_system_available(bool system_available) { system_available_ = system_available; }
    bool system_loaded() const { return system_loaded_; }

private:
    zx::job devhost_job_;
    async_dispatcher_t* dispatcher_;
    bool require_system_;

    bool running_ = false;
    DevhostLoaderService* loader_service_ = nullptr;

    // All Drivers
    fbl::DoublyLinkedList<Driver*, Driver::Node> drivers_;

    // Drivers to try last
    fbl::DoublyLinkedList<Driver*, Driver::Node> fallback_drivers_;

    // List of drivers loaded from /system by system_driver_loader()
    fbl::DoublyLinkedList<Driver*, Driver::Node> system_drivers_;

    // All Devices (excluding static immortal devices)
    fbl::DoublyLinkedList<Device*, Device::AllDevicesNode> devices_;

    // All DevHosts
    fbl::DoublyLinkedList<Devhost*, Devhost::AllDevhostsNode> devhosts_;

    Device root_device_{this};
    Device misc_device_{this};
    Device sys_device_{this};
    Device test_device_{this};

    SuspendContext suspend_context_;

    fbl::DoublyLinkedList<fbl::unique_ptr<Metadata>, Metadata::Node> published_metadata_;

    bool suspend_fallback_ = false;
    bool suspend_debug_ = false;
    bool system_available_ = false;
    bool system_loaded_ = false;
};

void coordinator_setup(Coordinator* coordinator, DevmgrArgs args);
void devmgr_set_bootdata(zx::unowned_vmo vmo);

using DriverLoadCallback = fit::function<void(Driver* driver, const char* version)>;

void load_driver(const char* path, DriverLoadCallback func);
void find_loadable_drivers(const char* path, DriverLoadCallback func);

bool dc_is_bindable(const Driver* drv, uint32_t protocol_id,
                    zx_device_prop_t* props, size_t prop_count,
                    bool autobind);

extern bool dc_asan_drivers;
extern bool dc_launched_first_devhost;

// Methods for composing FIDL RPCs to the devhosts
zx_status_t dh_send_remove_device(const Device* dev);
zx_status_t dh_send_create_device(Device* dev, Devhost* dh, zx::channel rpc, zx::vmo driver,
                                  const char* args, zx::handle rpc_proxy);
zx_status_t dh_send_create_device_stub(Devhost* dh, zx::channel rpc, uint32_t protocol_id);
zx_status_t dh_send_bind_driver(Device* dev, const char* libname, zx::vmo driver);
zx_status_t dh_send_connect_proxy(const Device* dev, zx::channel proxy);
zx_status_t dh_send_suspend(const Device* dev, uint32_t flags);

} // namespace devmgr