//go:build cgo && native_libs && linux
// +build cgo,native_libs,linux

package worker

// #cgo LDFLAGS: -L${SRCDIR}/../../native/build -Wl,-rpath,${SRCDIR}/../../native/build -lnvml_gpu -lnvidia-ml
// #include "../../native/nvml_gpu/nvml_gpu.h"
// #include <stdlib.h>
import "C"
import (
	"errors"
	"fmt"
)

// GPUInfo holds information about a GPU
type GPUInfo struct {
	Index        uint32
	Name         string
	Utilization  uint32 // GPU utilization percentage (0-100)
	MemoryUsed   uint64 // Memory used in bytes
	MemoryTotal  uint64 // Total memory in bytes
	Temperature  uint32 // Temperature in Celsius
	PowerDraw    uint32 // Power draw in milliwatts
	ClockSM      uint32 // SM clock in MHz
	ClockMemory  uint32 // Memory clock in MHz
	PCIeGen      uint32 // PCIe generation
	PCIeWidth    uint32 // PCIe link width
	UUID         string // GPU UUID
	VBIOSVersion string // VBIOS version
}

var (
	nvmlInitialized = false
)

// InitNVML initializes the NVML library
func InitNVML() error {
	result := C.gpu_init()
	if result != 0 {
		return errors.New(C.GoString(C.gpu_last_error()))
	}
	nvmlInitialized = true
	return nil
}

// ShutdownNVML shuts down the NVML library
func ShutdownNVML() {
	if nvmlInitialized {
		C.gpu_shutdown()
		nvmlInitialized = false
	}
}

// IsNVMLAvailable checks if NVML is available at runtime
func IsNVMLAvailable() bool {
	return C.gpu_is_available() == 1
}

// GetGPUCount returns the number of GPUs
func GetGPUCount() (int, error) {
	if !nvmlInitialized {
		if err := InitNVML(); err != nil {
			return 0, err
		}
	}

	count := C.gpu_get_count()
	if count < 0 {
		return 0, errors.New(C.GoString(C.gpu_last_error()))
	}
	return int(count), nil
}

// GetGPUInfo returns detailed information about a GPU
func GetGPUInfo(index uint32) (*GPUInfo, error) {
	if !nvmlInitialized {
		if err := InitNVML(); err != nil {
			return nil, err
		}
	}

	var cInfo C.gpu_info_t
	result := C.gpu_get_info(C.uint32_t(index), &cInfo)
	if result != 0 {
		return nil, errors.New(C.GoString(C.gpu_last_error()))
	}

	return &GPUInfo{
		Index:        uint32(cInfo.index),
		Name:         C.GoString(&cInfo.name[0]),
		Utilization:  uint32(cInfo.utilization),
		MemoryUsed:   uint64(cInfo.memory_used),
		MemoryTotal:  uint64(cInfo.memory_total),
		Temperature:  uint32(cInfo.temperature),
		PowerDraw:    uint32(cInfo.power_draw),
		ClockSM:      uint32(cInfo.clock_sm),
		ClockMemory:  uint32(cInfo.clock_memory),
		PCIeGen:      uint32(cInfo.pcie_gen),
		PCIeWidth:    uint32(cInfo.pcie_width),
		UUID:         C.GoString(&cInfo.uuid[0]),
		VBIOSVersion: C.GoString(&cInfo.vbios_version[0]),
	}, nil
}

// GetAllGPUInfo returns information about all GPUs
func GetAllGPUInfo() ([]*GPUInfo, error) {
	count, err := GetGPUCount()
	if err != nil {
		return nil, err
	}

	gpus := make([]*GPUInfo, 0, count)
	for i := 0; i < count; i++ {
		info, err := GetGPUInfo(uint32(i))
		if err != nil {
			return nil, fmt.Errorf("failed to get GPU %d info: %w", i, err)
		}
		gpus = append(gpus, info)
	}
	return gpus, nil
}

// GetGPUUtilization returns the current GPU utilization
func GetGPUUtilization(index uint32) (uint32, error) {
	if !nvmlInitialized {
		if err := InitNVML(); err != nil {
			return 0, err
		}
	}

	var utilization C.uint32_t
	result := C.gpu_get_utilization(C.uint32_t(index), &utilization)
	if result != 0 {
		return 0, errors.New(C.GoString(C.gpu_last_error()))
	}
	return uint32(utilization), nil
}

// GetGPUMemory returns the current GPU memory usage
func GetGPUMemory(index uint32) (used uint64, total uint64, err error) {
	if !nvmlInitialized {
		if err := InitNVML(); err != nil {
			return 0, 0, err
		}
	}

	var cUsed, cTotal C.uint64_t
	result := C.gpu_get_memory(C.uint32_t(index), &cUsed, &cTotal)
	if result != 0 {
		return 0, 0, errors.New(C.GoString(C.gpu_last_error()))
	}
	return uint64(cUsed), uint64(cTotal), nil
}

// GetGPUTemperature returns the current GPU temperature
func GetGPUTemperature(index uint32) (uint32, error) {
	if !nvmlInitialized {
		if err := InitNVML(); err != nil {
			return 0, err
		}
	}

	var temp C.uint32_t
	result := C.gpu_get_temperature(C.uint32_t(index), &temp)
	if result != 0 {
		return 0, errors.New(C.GoString(C.gpu_last_error()))
	}
	return uint32(temp), nil
}