// Copyright 2022 PingCAP, Inc.

use lazy_static::lazy_static;
use prometheus::{
    Histogram, HistogramVec, IntCounter, IntCounterVec, IntGauge, exponential_buckets,
    register_histogram, register_histogram_vec, register_int_counter, register_int_counter_vec,
    register_int_gauge,
};
use prometheus_static_metric::{auto_flush_from, make_auto_flush_static_metric};

make_auto_flush_static_metric! {
    pub label_enum DfsType {
        s3,
        local,
        azure,
    }

    pub label_enum S3ApiType {
        get,
        put,
        delete,
        list,
        head,
        copy,
        get_tagging,
        begin_multipart_upload,
        upload_part,
        complete_multipart_upload,
        abort_multipart_upload,
    }

    pub label_enum MetricsFileType {
        sst,
        txn,
        schema,
        col,
        blob,
        vec,
        unknown,
    }

    pub struct KvEngineDfsThroughput: LocalIntCounter {
        "dfs_type" => DfsType,
        "type" => S3ApiType,
        "file_type" => MetricsFileType,
    }

    pub struct KvEngineDfsLatency: LocalHistogram {
        "type" => S3ApiType,
        "file_type" => MetricsFileType,
    }

    pub struct KvEngineDfsLatencyWithRetry: LocalHistogram {
        "type" => S3ApiType,
        "file_type" => MetricsFileType,
    }

    pub struct KvEngineDfsRequestCounter: LocalIntCounter {
        "type" => S3ApiType,
        "file_type" => MetricsFileType,
    }

    pub struct KvEngineDfsRetryCounter: LocalIntCounter {
        "type" => S3ApiType,
        "file_type" => MetricsFileType,
    }

    pub struct KvEngineDfsThrottled: LocalHistogram {
        "dfs_type" => DfsType,
        "type" => S3ApiType,
    }
}

impl From<&str> for MetricsFileType {
    fn from(s: &str) -> Self {
        match s {
            "sst" => MetricsFileType::sst,
            "blob" => MetricsFileType::blob,
            "txn" => MetricsFileType::txn,
            "schema" => MetricsFileType::schema,
            "col" => MetricsFileType::col,
            "vec" => MetricsFileType::vec,
            _ => MetricsFileType::unknown,
        }
    }
}

lazy_static! {
    pub static ref KVENGINE_DFS_THROUGHPUT_VEC: IntCounterVec = register_int_counter_vec!(
        "kv_engine_dfs_throughput_bytes",
        "Throughput of kvengine dfs by dfs_type, S3 API type and file type",
        &["dfs_type", "type", "file_type"]
    )
    .unwrap();
    // TODO(hhwyt): The following metrics may also need to be tagged by dfs_type.
    pub static ref KVENGINE_DFS_LATENCY_VEC: HistogramVec = register_histogram_vec!(
        "kv_engine_dfs_latency_seconds",
        "Latency of kvengine dfs in seconds by S3 API type and file type",
        &["type", "file_type"],
        exponential_buckets(0.001, 2.0, 20).unwrap()
    )
    .unwrap();
    pub static ref KVENGINE_DFS_LATENCY_WITH_RETRY_VEC: HistogramVec = register_histogram_vec!(
        "kv_engine_dfs_latency_with_retry_seconds",
        "Latency of kvengine dfs including retry time in seconds by S3 API type and file type",
        &["type", "file_type"],
        exponential_buckets(0.001, 2.0, 20).unwrap()
    )
    .unwrap();
    pub static ref KVENGINE_DFS_REQUEST_COUNTER_VEC: IntCounterVec = register_int_counter_vec!(
        "kv_engine_dfs_request_counter",
        "Count of kvengine dfs requests by S3 API type and file type",
        &["type", "file_type"]
    )
    .unwrap();
    pub static ref KVENGINE_DFS_RETRY_COUNTER_VEC: IntCounterVec = register_int_counter_vec!(
        "kv_engine_dfs_retry_counter",
        "Retries counter of kvengine dfs by S3 API type and file type",
        &["type", "file_type"]
    )
    .unwrap();
    pub static ref KVENGINE_DFS_THROTTLED_VEC: HistogramVec = register_histogram_vec!(
        "kv_engine_dfs_throttled_seconds",
        "Time spent throttling kvengine dfs in seconds by dfs_type and S3 API type",
        &["dfs_type", "type"],
        exponential_buckets(0.001, 2.0, 20).unwrap()
    )
    .unwrap();
    pub static ref KVENGINE_CACHEFS_REQ_COUNTER_VEC: IntCounterVec = register_int_counter_vec!(
        "kv_engine_cachefs_req_count",
        "Count of kvengine cachefs requests hit/miss",
        &["type"]
    )
    .unwrap();
    pub static ref STRICT_FILE_MEMORY_QUOTA_WAIT_TIMEOUT: IntCounter = register_int_counter!(
        "kv_engine_strict_file_memory_quota_wait_timeout",
        "Strict file memory quota reservations that exhausted the wait budget and failed",
    )
    .unwrap();
    pub static ref STRICT_FILE_MEMORY_QUOTA_WAIT_SECONDS: Histogram = register_histogram!(
        "kv_engine_strict_file_memory_quota_wait_seconds",
        "Time spent waiting for strict file memory quota to free on reserve",
        exponential_buckets(0.001, 2.0, 14).unwrap()
    )
    .unwrap();
    pub static ref STRICT_FILE_MEMORY_QUOTA_NOHINT_FALLBACK: IntCounter = register_int_counter!(
        "kv_engine_strict_file_memory_quota_nohint_fallback_total",
        "cop-worker IA-disabled reads that bypassed the strict file memory quota \
         because the caller did not provide a size hint (Schema / TxnChunk / Fts). \
         Expected to stay low-volume; sustained growth means those file types \
         now contribute meaningful bytes and should be covered by the quota.",
    )
    .unwrap();
    pub static ref KVENGINE_DFS_MULTIPART_RUNNING_UPLOADS: IntGauge = register_int_gauge!(
        "kv_engine_dfs_multipart_running_uploads",
        "Number of running DFS multipart upload part requests",
    )
    .unwrap();
}

lazy_static! {
    pub static ref KVENGINE_DFS_THROUGHPUT: KvEngineDfsThroughput =
        auto_flush_from!(KVENGINE_DFS_THROUGHPUT_VEC, KvEngineDfsThroughput);
    pub static ref KVENGINE_DFS_LATENCY: KvEngineDfsLatency =
        auto_flush_from!(KVENGINE_DFS_LATENCY_VEC, KvEngineDfsLatency);
    pub static ref KVENGINE_DFS_LATENCY_WITH_RETRY: KvEngineDfsLatencyWithRetry = auto_flush_from!(
        KVENGINE_DFS_LATENCY_WITH_RETRY_VEC,
        KvEngineDfsLatencyWithRetry
    );
    pub static ref KVENGINE_DFS_REQUEST_COUNTER: KvEngineDfsRequestCounter =
        auto_flush_from!(KVENGINE_DFS_REQUEST_COUNTER_VEC, KvEngineDfsRequestCounter);
    pub static ref KVENGINE_DFS_RETRY_COUNTER: KvEngineDfsRetryCounter =
        auto_flush_from!(KVENGINE_DFS_RETRY_COUNTER_VEC, KvEngineDfsRetryCounter);
    pub static ref KVENGINE_DFS_THROTTLED: KvEngineDfsThrottled =
        auto_flush_from!(KVENGINE_DFS_THROTTLED_VEC, KvEngineDfsThrottled);
}