package main

import (
	"flag"
	"fmt"
	"git.xdrm.io/logauth/schastsp/context"
	"git.xdrm.io/logauth/schastsp/internal/scha"
	"git.xdrm.io/logauth/schastsp/server"
	"os"
	"time"
)

func main() {

	executionStart := time.Now().UnixNano()

	/* (1) Flag management (cli arguments)
	---------------------------------------------------------*/
	/* (1) Secret folder */
	serverConfigPath := flag.String("file", "/tmp/schastsp_hash", "Configuration file, it will contain sensitive data (key), make sure to control it properly. (default: /tmp/schastsp_hash)")

	/* (2) Context window size */
	winSize := flag.Uint("win", 2000, "Time window value in ms. (default: 2000)")

	/* (3) Context minimum depth value */
	minDepth := flag.Uint("min", 0x0f0, "Minimum depth value. (default: 240)")

	/* (4) Context maximum depth value */
	maxDepth := flag.Uint("max", 0xfff, "Maximum depth value. (default: 4095)")

	/* (5) Context depth threshold */
	thrDepth := flag.Uint("thr", 0x00a, "Depth threshold protecting minimum depth to be reached. (default: 10)")

	/* (6) Synchronisation request (special order) */
	syncRequest := flag.Bool("sync", false, "If set, proceeds a synchronisation from standard input (synchronisation key).")

	/* (7) Parse flags */
	flag.Parse()

	/* (2) Create context + client
	---------------------------------------------------------*/
	/* (1) Create context */
	ctx, err := context.Create(float64(*winSize)/1e3, uint16(*minDepth), uint16(*thrDepth), uint16(*maxDepth))
	if err != nil {
		os.Stderr.WriteString(fmt.Sprintf("[SERVER_ERROR:context] %s\n", err))
		return
	}

	/* (2) Create server */
	ser, err := server.New(ctx, *serverConfigPath)
	if err != nil {
		os.Stderr.WriteString(fmt.Sprintf("[SERVER_ERROR:server] %s\n", err))
		return
	}

	/* (3) Dispatch execution
	---------------------------------------------------------*/
	/* (1) If synchronisation request */
	if *syncRequest {
		synchronisationCommit(ser)

		/* (2) If request handling */
	} else {

		err = ser.HandleRequest(os.Stdin, os.Stdout)
		if err != nil {
			os.Stderr.WriteString(fmt.Sprintf("[SERVER_ERROR:request] %s\n", err))
		}

	}

	executionStop := time.Now().UnixNano()
	nsElapsed := float64(executionStop - executionStart)
	usElapsed := float64(nsElapsed / 1e3)
	msElapsed := float64(usElapsed / 1e3)
	sElapsed := float64(msElapsed / 1e3)

	if sElapsed >= 1 {
		os.Stderr.WriteString(fmt.Sprintf("executed in %.3f s\n", sElapsed))
	} else if msElapsed >= 1 {
		os.Stderr.WriteString(fmt.Sprintf("executed in %.3f ms\n", msElapsed))
	} else if usElapsed >= 1 {
		os.Stderr.WriteString(fmt.Sprintf("executed in %.3f us\n", usElapsed))
	} else if nsElapsed >= 1 {
		os.Stderr.WriteString(fmt.Sprintf("executed in %.3f ns\n", nsElapsed))
	}

	return
}

func synchronisationCommit(ser *server.T) {

	/* (1) Try to read key from standard input */
	syncKey := make([]byte, scha.HSIZE)
	read, err := os.Stdin.Read(syncKey)
	if err != nil {
		os.Stderr.WriteString(fmt.Sprintf("[SERVER_ERROR:syncKey] %s\n", err))
		return
	}
	if uint16(read) != scha.HSIZE {
		os.Stderr.WriteString(fmt.Sprintf("[SERVER_ERROR:syncKey] Cannot read proper key size\n"))
		return
	}

	/* (2) Store synchronisation key */
	err = ser.SynchronisationKey(syncKey)
	if err != nil {
		os.Stderr.WriteString(fmt.Sprintf("[SERVER_ERROR:syncKey] %s\n", err))
		return
	}

	/* (3) Debug */
	os.Stdout.WriteString("Synchronisation key successfully written\n")

	return

}