// Copyright 2024 RustFS Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::node_identity::SERVER_LABEL;
use crate::{MetricDescriptor, MetricName, new_counter_md, new_gauge_md, subsystems};
use std::sync::LazyLock;

pub const PROCESS_PID_LABEL: &str = "process_pid";
pub const PROCESS_EXECUTABLE_NAME_LABEL: &str = "process_executable_name";
pub const DIRECTION_LABEL: &str = "direction";
pub const STATUS_LABEL: &str = "status";

const PROCESS_LABELS: &[&str] = &[SERVER_LABEL];
const PROCESS_WITH_ATTRIBUTES_LABELS: &[&str] = &[SERVER_LABEL, PROCESS_PID_LABEL, PROCESS_EXECUTABLE_NAME_LABEL];
const PROCESS_DISK_IO_LABELS: &[&str] = &[
    DIRECTION_LABEL,
    SERVER_LABEL,
    PROCESS_PID_LABEL,
    PROCESS_EXECUTABLE_NAME_LABEL,
];
const PROCESS_STATUS_LABELS: &[&str] = &[SERVER_LABEL, STATUS_LABEL];

/// Number of current READ locks on this peer
pub static PROCESS_LOCKS_READ_TOTAL_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessLocksReadTotal,
        "Number of current READ locks on this peer",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Number of current WRITE locks on this peer
pub static PROCESS_LOCKS_WRITE_TOTAL_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessLocksWriteTotal,
        "Number of current WRITE locks on this peer",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total user and system CPU time spent in seconds
pub static PROCESS_CPU_TOTAL_SECONDS_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_counter_md(
        MetricName::ProcessCPUTotalSeconds,
        "Total user and system CPU time spent in seconds",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total number of go routines running
pub static PROCESS_GO_ROUTINE_TOTAL_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessGoRoutineTotal,
        "Total number of go routines running",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total bytes read by the process from the underlying storage system including cache
pub static PROCESS_IO_RCHAR_BYTES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_counter_md(
        MetricName::ProcessIORCharBytes,
        "Total bytes read by the process from the underlying storage system including cache, /proc/[pid]/io rchar",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total bytes read by the process from the underlying storage system
pub static PROCESS_IO_READ_BYTES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_counter_md(
        MetricName::ProcessIOReadBytes,
        "Total bytes read by the process from the underlying storage system, /proc/[pid]/io read_bytes",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total bytes written by the process to the underlying storage system including page cache
pub static PROCESS_IO_WCHAR_BYTES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_counter_md(
        MetricName::ProcessIOWCharBytes,
        "Total bytes written by the process to the underlying storage system including page cache, /proc/[pid]/io wchar",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total bytes written by the process to the underlying storage system
pub static PROCESS_IO_WRITE_BYTES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_counter_md(
        MetricName::ProcessIOWriteBytes,
        "Total bytes written by the process to the underlying storage system, /proc/[pid]/io write_bytes",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Start time for RustFS process in seconds since Unix epoch
pub static PROCESS_START_TIME_SECONDS_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessStartTimeSeconds,
        "Start time for RustFS process in seconds since Unix epoch",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Uptime for RustFS process in seconds
pub static PROCESS_UPTIME_SECONDS_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessUptimeSeconds,
        "Uptime for RustFS process in seconds",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Limit on total number of open file descriptors for the RustFS Server process
pub static PROCESS_FILE_DESCRIPTOR_LIMIT_TOTAL_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessFileDescriptorLimitTotal,
        "Limit on total number of open file descriptors for the RustFS Server process",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total number of open file descriptors by the RustFS Server process
pub static PROCESS_FILE_DESCRIPTOR_OPEN_TOTAL_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessFileDescriptorOpenTotal,
        "Total number of open file descriptors by the RustFS Server process",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total read SysCalls to the kernel
pub static PROCESS_SYSCALL_READ_TOTAL_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_counter_md(
        MetricName::ProcessSyscallReadTotal,
        "Total read SysCalls to the kernel. /proc/[pid]/io syscr",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Total write SysCalls to the kernel
pub static PROCESS_SYSCALL_WRITE_TOTAL_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_counter_md(
        MetricName::ProcessSyscallWriteTotal,
        "Total write SysCalls to the kernel. /proc/[pid]/io syscw",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Resident memory size in bytes
pub static PROCESS_RESIDENT_MEMORY_BYTES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessResidentMemoryBytes,
        "Resident memory size in bytes",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Virtual memory size in bytes
pub static PROCESS_VIRTUAL_MEMORY_BYTES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessVirtualMemoryBytes,
        "Virtual memory size in bytes",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Maximum virtual memory size in bytes
pub static PROCESS_VIRTUAL_MEMORY_MAX_BYTES_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessVirtualMemoryMaxBytes,
        "Maximum virtual memory size in bytes",
        PROCESS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

// ============================================================================
// Process-level system monitoring metrics (migrated from rustfs-obs::system)
// ============================================================================

/// Process CPU usage percentage (0-100)
pub static PROCESS_CPU_USAGE_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessCPUUsage,
        "The percentage of CPU in use by the process",
        PROCESS_WITH_ATTRIBUTES_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Process CPU utilization percentage (considering multiple cores)
pub static PROCESS_CPU_UTILIZATION_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessCPUUtilization,
        "The amount of CPU in use by the process (considering multiple cores)",
        PROCESS_WITH_ATTRIBUTES_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Process disk I/O bytes
pub static PROCESS_DISK_IO_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessDiskIO,
        "Disk bytes transferred by the process",
        PROCESS_DISK_IO_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});

/// Process status (0: Running, 1: Sleeping, 2: Zombie, 3: Other)
pub static PROCESS_STATUS_MD: LazyLock<MetricDescriptor> = LazyLock::new(|| {
    new_gauge_md(
        MetricName::ProcessStatus,
        "Process status (0: Running, 1: Sleeping, 2: Zombie, 3: Other)",
        PROCESS_STATUS_LABELS,
        subsystems::SYSTEM_PROCESS,
    )
});
