package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strings"
)

const filePath string = "./data/users.txt"

//easyjson:json
type User struct {
	Name     string   `json:"name"`
	Email    string   `json:"email"`
	Browsers []string `json:"browsers"`
}

// Only for easyjson generation
func main() {
	u := &User{}
	u.UnmarshalJSON([]byte(`{"browsers":["Mozilla","Second","Linux"],
                             "company":"Flashpoint",
                             "country":"Dominican Republic",
                             "email":"JonathanMorris@Muxo.edu",
                             "job":"Programmer",
                             "name":"Sharon Crawford",
                             "phone":"176-88-49"}`))
	fmt.Println(u)
}

// Fastest IntToStr
func String(i int) string {
	buf := [11]byte{}
	pos := len(buf)
	signed := i < 0
	if signed {
		i = -i
	}
	for {
		pos--
		buf[pos], i = '0'+byte(i%10), i/10
		if i == 0 {
			if signed {
				pos--
				buf[pos] = '-'
			}
			return string(buf[pos:])
		}
	}
}

func FastSearch(out io.Writer) {

	var q struct{}
	var buffer bytes.Buffer

	file, err := os.Open(filePath)
	defer file.Close()
	if err != nil {
		panic(err)
	}

	user := &User{}
	seenBrowsers := make(map[string]struct{}, 0)
	scanner := bufio.NewScanner(file)
	buffer.WriteString("found users:\n")
	idx := 0

	for scanner.Scan() {

		err := user.UnmarshalJSON(scanner.Bytes())
		if err != nil {
			panic(err)
		}

		isAndroid := false
		isMSIE := false

		for _, browser := range user.Browsers {
			if strings.Contains(browser, "Android") {
				isAndroid = true
				if _, ok := seenBrowsers[browser]; !ok {
					seenBrowsers[browser] = q
				}
			}
			if strings.Contains(browser, "MSIE") {
				isMSIE = true
				if _, ok := seenBrowsers[browser]; !ok {
					seenBrowsers[browser] = q
				}
			}
		}

		if isAndroid && isMSIE {
			email := strings.Replace(user.Email, "@", " [at] ", -1)
			buffer.WriteString("[" + String(idx) + "] " + user.Name + " <" + email + ">\n")
		}

		idx++
	}

	buffer.WriteString("\nTotal unique browsers " + String(len(seenBrowsers)))
	fmt.Fprintln(out, buffer.String())
}