package logparser

import (
	"fmt"
	"log"
	"math"
	"os"
	"regexp"
	"strconv"
	"strings"
	"time"

	"github.com/gomodule/redigo/redis"
	"gonum.org/v1/plot"
	"gonum.org/v1/plot/plotter"
	"gonum.org/v1/plot/plotutil"
	"gonum.org/v1/plot/vg"
)

// SshdParser Holds a struct that corresponds to a sshd log line
// and the redis connection
type SshdParser struct {
	r1 *redis.Conn
	r2 *redis.Conn
}

// Set set the redic connection to this parser
func (s *SshdParser) Set(rconn1 *redis.Conn, rconn2 *redis.Conn) {
	s.r1 = rconn1
	s.r2 = rconn2
}

// Parse parses a line of sshd log
func (s *SshdParser) Parse(logline string) error {
	r := *s.r1
	re := regexp.MustCompile(`^(?P<date>[[:alpha:]]{3}\s\d{2}\s\d{2}:\d{2}:\d{2}) (?P<host>[^ ]+) sshd\[[[:alnum:]]+\]: Invalid user (?P<username>[^ ]+) from (?P<src>.*$)`)
	n1 := re.SubexpNames()
	r2 := re.FindAllStringSubmatch(logline, -1)[0]

	// Build the group map for the line
	md := map[string]string{}
	for i, n := range r2 {
		// fmt.Printf("%d. match='%s'\tname='%s'\n", i, n, n1[i])
		md[n1[i]] = n
	}

	// Assumes the system parses logs recorded during the current year
	md["date"] = fmt.Sprintf("%v %v", md["date"], time.Now().Year())
	// Make this automatic or a config parameter
	loc, _ := time.LoadLocation("Europe/Luxembourg")
	parsedTime, _ := time.ParseInLocation("Jan 02 15:04:05 2006", md["date"], loc)
	md["date"] = string(strconv.FormatInt(parsedTime.Unix(), 10))

	// Pushing loglines in database 0
	if _, err := r.Do("SELECT", 0); err != nil {
		r.Close()
		return err
	}
	_, err := redis.Bool(r.Do("HSET", fmt.Sprintf("%v:%v", md["date"], md["host"]), "username", md["username"], "src", md["src"]))
	if err != nil {
		r.Close()
		return err
	}

	// Pushing statistics in database 1
	if _, err := r.Do("SELECT", 1); err != nil {
		r.Close()
		return err
	}
	_, err = redis.String(r.Do("ZINCRBY", fmt.Sprintf("%v%v%v:statssrc", parsedTime.Year(), int(parsedTime.Month()), parsedTime.Day()), 1, md["src"]))
	if err != nil {
		r.Close()
		return err
	}
	_, err = redis.String(r.Do("ZINCRBY", fmt.Sprintf("%v%v%v:statsusername", parsedTime.Year(), int(parsedTime.Month()), parsedTime.Day()), 1, md["username"]))
	if err != nil {
		r.Close()
		return err
	}
	_, err = redis.String(r.Do("ZINCRBY", fmt.Sprintf("%v%v%v:statshost", parsedTime.Year(), int(parsedTime.Month()), parsedTime.Day()), 1, md["host"]))
	if err != nil {
		r.Close()
		return err
	}

	// Keeping track of which days we updated statistics for
	_, err = redis.Int(r.Do("SADD", "toupdate", fmt.Sprintf("%v%v%v:statssrc", parsedTime.Year(), int(parsedTime.Month()), parsedTime.Day())))
	if err != nil {
		r.Close()
		return err
	}
	_, err = redis.Int(r.Do("SADD", "toupdate", fmt.Sprintf("%v%v%v:statsusername", parsedTime.Year(), int(parsedTime.Month()), parsedTime.Day())))
	if err != nil {
		r.Close()
		return err
	}
	_, err = redis.Int(r.Do("SADD", "toupdate", fmt.Sprintf("%v%v%v:statshost", parsedTime.Year(), int(parsedTime.Month()), parsedTime.Day())))
	if err != nil {
		r.Close()
		return err
	}

	return nil
}

// Compile create graphs of the results
func (s *SshdParser) Compile() error {
	r := *s.r2

	// Pulling statistics from database 1
	if _, err := r.Do("SELECT", 1); err != nil {
		r.Close()
		return err
	}

	// List days for which we need to update statistic
	toupdate, err := redis.Strings(r.Do("SMEMBERS", "toupdate"))
	if err != nil {
		r.Close()
		return err
	}

	// Query statistics dor each day to update
	for _, v := range toupdate {
		zrank, err := redis.Strings(r.Do("ZRANGEBYSCORE", v, "-inf", "+inf", "WITHSCORES"))
		if err != nil {
			r.Close()
			return err
		}

		// Split keys and values - keep these ordered
		values := plotter.Values{}
		keys := make([]string, 0, len(zrank)/2)

		for k, v := range zrank {
			// keys
			if (k % 2) == 0 {
				keys = append(keys, zrank[k])
				// values
			} else {
				fv, _ := strconv.ParseFloat(v, 64)
				values = append(values, fv)
			}
		}

		p, err := plot.New()
		if err != nil {
			panic(err)
		}

		stype := strings.Split(v, ":")
		switch stype[1] {
		case "statsusername":
			p.Title.Text = "Usernames"
		case "statssrc":
			p.Title.Text = "Source IP"
		case "statshost":
			p.Title.Text = "Host"
		default:
			p.Title.Text = ""
			log.Println("We should not reach this point, open an issue.")
		}

		p.Y.Label.Text = "Count"
		w := 0.5 * vg.Centimeter
		bc, err := plotter.NewBarChart(values, w)
		bc.Horizontal = true
		if err != nil {
			return err
		}
		bc.LineStyle.Width = vg.Length(0)
		bc.Color = plotutil.Color(0)

		p.Add(bc)
		p.NominalY(keys...)

		// Create folder to store plots
		if _, err := os.Stat(stype[0]); os.IsNotExist(err) {
			os.Mkdir(stype[0], 0700)
		}

		xsize := 3 + vg.Length(math.Round(float64(len(keys)/2)))
		if err := p.Save(15*vg.Centimeter, xsize*vg.Centimeter, fmt.Sprintf("data/%v/%v.svg", stype[0], v)); err != nil {
			return err
		}

	}

	return nil
}