package ingest

import (
	"encoding/json"
	"fmt"
	"net"
	"strconv"
	"strings"
	"time"

	"github.com/gosnmp/gosnmp"
)

type timeWindow struct {
	Days  []int  `json:"days"`
	Start string `json:"start"`
	End   string `json:"end"`
}

func ipMatchesCIDR(ip net.IP, cidr string) bool {
	cidr = strings.TrimSpace(cidr)
	if cidr == "" {
		return false
	}
	if !strings.Contains(cidr, "/") {
		p := net.ParseIP(cidr)
		return p != nil && p.Equal(ip)
	}
	_, network, err := net.ParseCIDR(cidr)
	if err != nil {
		return false
	}
	return network.Contains(ip)
}

func inTimeWindows(now time.Time, jsonStr string) bool {
	s := strings.TrimSpace(jsonStr)
	if s == "" || s == "null" {
		return true
	}
	var windows []timeWindow
	if err := json.Unmarshal([]byte(s), &windows); err != nil || len(windows) == 0 {
		return true
	}
	tod := now.Hour()*60 + now.Minute()
	wd := int(now.Weekday())
	for _, w := range windows {
		if len(w.Days) > 0 {
			ok := false
			for _, d := range w.Days {
				if d == wd {
					ok = true
					break
				}
			}
			if !ok {
				continue
			}
		}
		start := parseHHMM(w.Start)
		end := parseHHMM(w.End)
		if start < 0 || end < 0 {
			continue
		}
		if start <= end {
			if tod >= start && tod <= end {
				return true
			}
		} else {
			if tod >= start || tod <= end {
				return true
			}
		}
	}
	return false
}

func parseHHMM(s string) int {
	s = strings.TrimSpace(s)
	if s == "" {
		return -1
	}
	parts := strings.Split(s, ":")
	if len(parts) != 2 {
		return -1
	}
	h, err1 := strconv.Atoi(parts[0])
	m, err2 := strconv.Atoi(parts[1])
	if err1 != nil || err2 != nil || h < 0 || h > 23 || m < 0 || m > 59 {
		return -1
	}
	return h*60 + m
}

func varbindFingerprint(pkt *gosnmp.SnmpPacket) string {
	var b strings.Builder
	for _, v := range pkt.Variables {
		b.WriteString(v.Name)
		b.WriteByte('=')
		b.WriteString(fmtVarbindValue(v))
		b.WriteByte(';')
	}
	return b.String()
}

func fmtVarbindValue(v gosnmp.SnmpPDU) string {
	switch v.Type {
	case gosnmp.OctetString:
		if bb, ok := v.Value.([]byte); ok {
			return string(bb)
		}
	}
	return fmt.Sprintf("%v", v.Value)
}