package fingerprint

import (
	"fmt"
	"log"

	"github.com/hashicorp/nomad/client/config"
	"github.com/hashicorp/nomad/helper/stats"
	"github.com/hashicorp/nomad/nomad/structs"
)

// CPUFingerprint is used to fingerprint the CPU
type CPUFingerprint struct {
	StaticFingerprinter
	logger *log.Logger
}

// NewCPUFingerprint is used to create a CPU fingerprint
func NewCPUFingerprint(logger *log.Logger) Fingerprint {
	f := &CPUFingerprint{logger: logger}
	return f
}

func (f *CPUFingerprint) Fingerprint(cfg *config.Config, node *structs.Node) (bool, error) {
	setResources := func(totalCompute int) {
		if node.Resources == nil {
			node.Resources = &structs.Resources{}
		}

		node.Resources.CPU = totalCompute
	}

	if err := stats.Init(); err != nil {
		err := fmt.Errorf("Unable to obtain CPU information: %v", err)

		if cfg.CpuCompute != 0 {
			f.logger.Printf("[DEBUG] fingerprint.cpu: %v. Using specified cpu compute %d", err, cfg.CpuCompute)
			setResources(cfg.CpuCompute)
			return true, nil
		}

		f.logger.Printf("[ERR] fingerprint.cpu: %v", err)
		f.logger.Printf("[INFO] fingerprint.cpu: cpu compute may be set manually"+
			" using the client config option %q on machines where cpu information"+
			" can not be automatically detected.", "cpu_total_compute")

		return false, err
	}

	modelName := stats.CPUModelName()
	if modelName != "" {
		node.Attributes["cpu.modelname"] = modelName
	}

	mhz := stats.CPUMHzPerCore()
	node.Attributes["cpu.frequency"] = fmt.Sprintf("%.0f", mhz)
	f.logger.Printf("[DEBUG] fingerprint.cpu: frequency: %.0f MHz", mhz)

	numCores := stats.CPUNumCores()
	node.Attributes["cpu.numcores"] = fmt.Sprintf("%d", numCores)
	f.logger.Printf("[DEBUG] fingerprint.cpu: core count: %d", numCores)

	tt := stats.TotalTicksAvailable()

	node.Attributes["cpu.totalcompute"] = fmt.Sprintf("%.0f", tt)

	setResources(int(tt))
	return true, nil
}