// Copyright 2018 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 <stdint.h>
#include <unistd.h>

#include <cobalt-client/cpp/metric-options.h>

#include <fbl/string.h>
#include <fbl/vector.h>
// TODO(gevalentino): Remove when host code diverges from target code in filesystems,
// and host/target compatibility is not required.
#ifdef __Fuchsia__
#include <fuchsia/cobalt/c/fidl.h>
#endif

namespace cobalt_client {
namespace internal {
// Note: Everything on this namespace is internal, no external users should rely
// on the behaviour of any of these classes.
// A value pair which represents a bucket index and the count for such index.

// TODO(gevalentino): Remove when host code diverges from target code in filesystems,
// and host/target compatibility is not required.
#ifdef __Fuchsia__
using HistogramBucket = fuchsia_cobalt_HistogramBucket;

enum class ReleaseStage : fuchsia_cobalt_ReleaseStage {
    kGa = fuchsia_cobalt_ReleaseStage_GA,
    kDogfood = fuchsia_cobalt_ReleaseStage_DOGFOOD,
    kFishfood = fuchsia_cobalt_ReleaseStage_FISHFOOD,
    kDebug = fuchsia_cobalt_ReleaseStage_DEBUG,
};
#else
struct HistogramBucket {
    uint32_t index;
    int64_t count;
};

enum class ReleaseStage {
    kGa,
    kDogfood,
    kFishfood,
    kDebug,
};
#endif

struct RemoteMetricInfo {
    // Generates |name| from the contents of metric options.
    static RemoteMetricInfo From(const MetricOptions& options);

    RemoteMetricInfo() = default;
    RemoteMetricInfo(const RemoteMetricInfo&) = default;

    // Allows comparing two |RemoteMetricInfo|, which is a shortcut for checking if
    // all fields are equal.
    bool operator==(const RemoteMetricInfo& rhs) const;
    bool operator!=(const RemoteMetricInfo& rhs) const;

    // Provides refined metric collection for remote metrics.
    // Warning: |component| is not yet supported in the backend, so it will be ignored.
    fbl::String component;

    // Used by remote metrics to match with the respective unique id for the projects defined
    // metrics in the backend.
    uint32_t metric_id;

    // Provides refined metric collection for remote metrics.
    // Warning: |event_code| is not yet supported in the backend, so it will be treated as 0.
    uint32_t event_code;
};

struct LocalMetricInfo {
    // Generates |name| from the contents of metric options.
    static LocalMetricInfo From(const MetricOptions& options);

    LocalMetricInfo() = default;
    LocalMetricInfo(const LocalMetricInfo&) = default;
    bool operator==(const LocalMetricInfo& rhs) const;
    bool operator!=(const LocalMetricInfo& rhs) const;

    fbl::String name;
};

// Interface for Logger class. There is no requirement on what to do with the data
// in the logging buffer, that is up to the implementation.
// The default implementation is |CobaltLogger|.
class Logger {
public:
    virtual ~Logger() = default;

    // Adds the contents of buckets and the required info to a buffer.
    virtual bool Log(const RemoteMetricInfo& remote_info, const HistogramBucket* buckets,
                     size_t num_buckets) = 0;

    // Adds the count and the required info to a buffer.
    virtual bool Log(const RemoteMetricInfo& remote_info, int64_t count) = 0;
};

// Flush Interface for the |Collector| to flush.
class FlushInterface {
public:
    virtual ~FlushInterface() = default;

    // Returns true if the data was added to the logger successfully.
    // Returns false if logger failed to flush the data.
    virtual bool Flush(Logger* logger) = 0;

    // Undo's the effect of the on going flush.
    virtual void UndoFlush() = 0;
};

} // namespace internal
} // namespace cobalt_client