package cisco

import (
	"fmt"
	"math/rand"
	"strings"
	"time"
)

func showVersion(s *iosState) string {
	days := 14 + rand.Intn(350)
	hours := rand.Intn(24)
	mins := rand.Intn(60)

	return fmt.Sprintf(`Cisco IOS Software, %s Software (%s-UNIVERSALK9-M), Version %s, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2019 by Cisco Systems, Inc.
Compiled Thu 30-Jan-19 10:08 by prod_rel_team

ROM: Bootstrap program is %s boot loader
BOOTLDR: %s Boot Loader (C2960-HBOOT-M) Version 15.0(2r)SE, RELEASE SOFTWARE (fc1)

%s uptime is %d days, %d hours, %d minutes
System returned to ROM by power-on
System image file is "flash:/%s-universalk9-mz.SPA.%s.bin"

This product contains cryptographic features and is subject to United States
and local country laws governing import, export, transfer and use.

cisco %s (%s) processor (revision K0) with 524288K bytes of memory.
Processor board ID %s
Last reset from power-on
2 Gigabit Ethernet interfaces
1 Virtual Ethernet interface
64K bytes of flash-simulated non-volatile configuration memory.
Total of 65536K bytes of APC System Flash (Read/Write)

Configuration register is 0x2102`,
		s.model, s.model, s.iosVersion,
		s.model, s.model,
		s.hostname, days, hours, mins,
		s.model, s.iosVersion,
		s.model, processorForModel(s.model),
		s.serial,
	)
}

func processorForModel(model string) string {
	if strings.HasPrefix(model, "C29") {
		return "PowerPC405"
	}
	return "MIPS"
}

func showClock() string {
	now := time.Now().UTC()
	return fmt.Sprintf("*%s UTC", now.Format("15:04:05.000 Mon Jan 2 2006"))
}

func showIPRoute(s *iosState) string {
	var b strings.Builder
	b.WriteString("Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP\n")
	b.WriteString("       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area\n")
	b.WriteString("       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2\n")
	b.WriteString("       E1 - OSPF external type 1, E2 - OSPF external type 2\n")
	b.WriteString("       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2\n")
	b.WriteString("       ia - IS-IS inter area, * - candidate default, U - per-user static route\n")
	b.WriteString("       o - ODR, P - periodic downloaded static route\n\n")
	b.WriteString("Gateway of last resort is 10.0.0.2 to network 0.0.0.0\n\n")

	for _, iface := range s.interfaces {
		if iface.ip == "unassigned" || iface.status != "up" {
			continue
		}
		network := networkFromIP(iface.ip, iface.mask)
		maskBits := maskBits(iface.mask)
		fmt.Fprintf(&b, "C       %s/%d is directly connected, %s\n", network, maskBits, iface.name)
	}
	b.WriteString("S*   0.0.0.0/0 [1/0] via 10.0.0.2")
	return b.String()
}

func showIPInterfaceBrief(s *iosState) string {
	var b strings.Builder
	fmt.Fprintf(&b, "%-25s %-15s %-4s %-7s %-22s %s\n",
		"Interface", "IP-Address", "OK?", "Method", "Status", "Protocol")
	for _, iface := range s.interfaces {
		ip := iface.ip
		if ip == "" {
			ip = "unassigned"
		}
		fmt.Fprintf(&b, "%-25s %-15s YES  manual  %-22s %s\n",
			iface.name, ip, iface.status, iface.protocol)
	}
	return b.String()
}

func showInterfaces(s *iosState) string {
	var b strings.Builder
	for i, iface := range s.interfaces {
		if i > 0 {
			b.WriteString("\n")
		}
		upDown := "up"
		if iface.shutdown {
			upDown = "administratively down"
		}
		fmt.Fprintf(&b, "%s is %s, line protocol is %s\n", iface.name, upDown, iface.protocol)
		fmt.Fprintf(&b, "  Hardware is Gigabit Ethernet, address is %s (bia %s)\n", iface.mac, iface.mac)
		if iface.ip != "unassigned" && iface.ip != "" {
			fmt.Fprintf(&b, "  Internet address is %s/%d\n", iface.ip, maskBits(iface.mask))
		}
		fmt.Fprintf(&b, "  MTU %d bytes, BW %s sec, DLY 10 usec,\n", iface.mtu, iface.bandwidth)
		b.WriteString("     reliability 255/255, txload 1/255, rxload 1/255\n")
		b.WriteString("  Encapsulation ARPA, loopback not set\n")
		fmt.Fprintf(&b, "     %d packets input, %d bytes, 0 no buffer\n", iface.rxPackets, iface.rxBytes)
		fmt.Fprintf(&b, "     %d packets output, %d bytes, 0 underruns", iface.txPackets, iface.txBytes)
	}
	return b.String()
}

func showRunningConfig(s *iosState) string {
	var b strings.Builder
	b.WriteString("Building configuration...\n\n")
	b.WriteString("Current configuration : 1482 bytes\n")
	b.WriteString("!\n")
	b.WriteString("! Last configuration change at 14:32:22 UTC Mon Feb 10 2025\n")
	b.WriteString("!\n")
	b.WriteString("version 15.0\n")
	b.WriteString("service timestamps debug datetime msec\n")
	b.WriteString("service timestamps log datetime msec\n")
	b.WriteString("no service password-encryption\n")
	b.WriteString("!\n")
	fmt.Fprintf(&b, "hostname %s\n", s.hostname)
	b.WriteString("!\n")
	b.WriteString("boot-start-marker\n")
	b.WriteString("boot-end-marker\n")
	b.WriteString("!\n")
	if s.enablePass != "" {
		b.WriteString("enable secret 5 $1$mERr$hx5rVt7rPNoS4wqbXKX7m0\n")
	}
	b.WriteString("!\n")
	b.WriteString("no aaa new-model\n")
	b.WriteString("!\n")

	for _, iface := range s.interfaces {
		b.WriteString("!\n")
		fmt.Fprintf(&b, "interface %s\n", iface.name)
		if iface.desc != "" {
			fmt.Fprintf(&b, " description %s\n", iface.desc)
		}
		if iface.ip != "unassigned" && iface.ip != "" {
			fmt.Fprintf(&b, " ip address %s %s\n", iface.ip, iface.mask)
		} else {
			b.WriteString(" no ip address\n")
		}
		if iface.shutdown {
			b.WriteString(" shutdown\n")
		}
	}

	b.WriteString("!\n")
	b.WriteString("ip forward-protocol nd\n")
	b.WriteString("!\n")
	b.WriteString("ip route 0.0.0.0 0.0.0.0 10.0.0.2\n")
	b.WriteString("!\n")
	b.WriteString("access-list 10 permit 192.168.1.0 0.0.0.255\n")
	b.WriteString("access-list 10 deny   any\n")
	b.WriteString("!\n")
	b.WriteString("line con 0\n")
	b.WriteString(" logging synchronous\n")
	b.WriteString("line vty 0 4\n")
	b.WriteString(" login local\n")
	b.WriteString(" transport input ssh\n")
	b.WriteString("!\n")
	b.WriteString("end")
	return b.String()
}

func showVLANBrief() string {
	var b strings.Builder
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s\n", "VLAN", "Name", "Status", "Ports")
	b.WriteString("---- -------------------------------- --------- -------------------------------\n")
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s\n", "1", "default", "active", "Gi0/0, Gi0/1, Gi0/2")
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s\n", "10", "MGMT", "active", "")
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s\n", "20", "USERS", "active", "")
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s\n", "99", "NATIVE", "active", "")
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s\n", "1002", "fddi-default", "act/unsup", "")
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s\n", "1003", "token-ring-default", "act/unsup", "")
	fmt.Fprintf(&b, "%-6s %-32s %-10s %s", "1004", "fddinet-default", "act/unsup", "")
	return b.String()
}

// networkFromIP derives the network address from an IP and mask.
func networkFromIP(ip, mask string) string {
	ipParts := parseIPv4(ip)
	maskParts := parseIPv4(mask)
	if ipParts == nil || maskParts == nil {
		return ip
	}
	return fmt.Sprintf("%d.%d.%d.%d",
		ipParts[0]&maskParts[0],
		ipParts[1]&maskParts[1],
		ipParts[2]&maskParts[2],
		ipParts[3]&maskParts[3],
	)
}

func maskBits(mask string) int {
	parts := parseIPv4(mask)
	if parts == nil {
		return 24
	}
	bits := 0
	for _, p := range parts {
		for i := 7; i >= 0; i-- {
			if p&(1<<uint(i)) != 0 {
				bits++
			} else {
				return bits
			}
		}
	}
	return bits
}

func parseIPv4(s string) []int {
	var a, b, c, d int
	n, _ := fmt.Sscanf(s, "%d.%d.%d.%d", &a, &b, &c, &d)
	if n != 4 {
		return nil
	}
	return []int{a, b, c, d}
}