package main

import (
	"bufio"
	"fmt"
	"io"
	"log"
	"os"
	"strings"
	"unsafe"

	"github.com/satyrius/gonx"
)

func scanner(initialBuf, maxBuf int, noallocate bool) {
	f, err := os.Open("./testdata/NASA_access_log_Aug95")
	if err != nil {
		log.Println(err.Error())
		return
	}
	defer f.Close()
	// in := strings.NewReader("1st line\n" + strings.Repeat("X", 65536) + "\n3rd line\n")

	scanner := bufio.NewScanner(f)
	buf := make([]byte, initialBuf)
	scanner.Buffer(buf, maxBuf)
	// dis := ioutil.Discard

	for scanner.Scan() {
		if !noallocate {
			s := scanner.Text()
			_ = strings.Split(s, " ")
			// for _, v := range sp {
			// 	dis.Write([]byte(v))
			// }
			// dis.Write([]byte(s))
		} else {
			b := scanner.Bytes()
			s := *(*string)(unsafe.Pointer(&b))
			_ = strings.Split(s, " ")
			// for _, v := range sp {
			// 	dis.Write([]byte(v))
			// }
			// dis.Write(b)
		}
	}

	if err := scanner.Err(); err != nil {
		fmt.Printf("Scanner error: %q\n", err)
	}
}

func scannerWithIndex(initialBuf, maxBuf int, noallocate bool) {
	f, err := os.Open("./testdata/NASA_access_log_Aug95")
	if err != nil {
		log.Println(err.Error())
		return
	}
	defer f.Close()
	// in := strings.NewReader("1st line\n" + strings.Repeat("X", 65536) + "\n3rd line\n")

	scanner := bufio.NewScanner(f)
	buf := make([]byte, initialBuf)
	scanner.Buffer(buf, maxBuf)
	// dis := ioutil.Discard

	for scanner.Scan() {
		if !noallocate {
			s := scanner.Text()
			_, err := splitWithIndex(s)
			if err != nil {
				fmt.Println(err.Error())
				return
			}
			// for _, v := range sp {
			// 	dis.Write([]byte(v))
			// }
		} else {
			b := scanner.Bytes()
			s := *(*string)(unsafe.Pointer(&b))
			_, err := splitWithIndex(s)
			if err != nil {
				fmt.Println(err.Error())
				return
			}
			// for _, v := range sp {
			// 	dis.Write([]byte(v))
			// }
		}
	}

	if err := scanner.Err(); err != nil {
		fmt.Printf("Scanner error: %q\n", err)
	}
}

func splitWithIndex(s string) ([]string, error) {
	sp := make([]string, 0, 32)
	if len(s) == 0 {
		return sp, nil
	}
	end := false
	for {
		i := strings.IndexByte(s, ' ')
		if i < 0 {
			end = true
		} else {
			ss := s[:i]
			sp = append(sp, ss)
		}
		s = s[i+1:]
		if end {
			break
		}
	}
	return sp, nil
}
func scannerWithGonx() {
	f, err := os.Open("./testdata/NASA_access_log_Aug95")
	if err != nil {
		log.Println(err.Error())
		return
	}
	defer f.Close()
	// in := strings.NewReader("1st line\n" + strings.Repeat("X", 65536) + "\n3rd line\n")
	format := "$remote_addr - - [$time_local] \"$request\" $in $in2"
	// parser := gonx.NewParser(format)
	reader := gonx.NewReader(f, format)

	// dis := ioutil.Discard
	var count int

	for {
		_, err := reader.Read()
		if err == io.EOF {
			break
		} else if err != nil {
			panic(err)
		}
		// fmt.Printf("%+v\n", rec)
		count++
	}

	fmt.Printf("%v lines readed\n", count)
}