package netcfg

import (
	"fmt"
	"strings"

	"gitea.apointless.space/bsncubed/ipswap/internal/preset"
)

// ConfirmText renders the before/after body of the confirmation MessageBox.
//
// The live side must be read at prompt time rather than taken from the cached
// active-preset poll: the prompt is the only safety net before a destructive
// change, and a 30-second-stale "CURRENT" block would undermine it.
func ConfirmText(p preset.Preset, live LiveConfig) string {
	var b strings.Builder

	fmt.Fprintf(&b, "Apply preset %q to adapter %q?\n\n", p.Name, p.Adapter)

	b.WriteString("CURRENT\n")
	writeLive(&b, live)

	b.WriteString("\nNEW\n")
	writePreset(&b, p)

	return b.String()
}

func writeLive(b *strings.Builder, live LiveConfig) {
	if len(live.Addresses) == 0 {
		b.WriteString("  (no IPv4 address)\n")
	}
	for i, a := range live.Addresses {
		suffix := ""
		if live.DHCP {
			suffix = " (DHCP)"
		}
		prefix := "  "
		if i > 0 {
			prefix = "  + "
		}
		fmt.Fprintf(b, "%s%s%s\n", prefix, a.String(), suffix)
	}
	if len(live.Gateways) > 0 {
		fmt.Fprintf(b, "  Gateway: %s\n", strings.Join(live.Gateways, ", "))
	}
	if len(live.DNS) > 0 {
		suffix := ""
		if live.DNSFromDHCP {
			suffix = " (DHCP)"
		}
		fmt.Fprintf(b, "  DNS: %s%s\n", strings.Join(live.DNS, ", "), suffix)
	}
}

func writePreset(b *strings.Builder, p preset.Preset) {
	if p.Mode == preset.ModeDHCP {
		b.WriteString("  DHCP\n")
	} else if p.Primary != nil {
		fmt.Fprintf(b, "  %s\n", p.Primary.String())
		for _, s := range p.Secondary {
			fmt.Fprintf(b, "  + %s\n", s.String())
		}
		if p.Primary.Gateway != "" {
			fmt.Fprintf(b, "  Gateway: %s\n", p.Primary.Gateway)
		}
	}

	switch p.DNS.Mode {
	case preset.ModeDHCP:
		b.WriteString("  DNS: from DHCP\n")
	default:
		fmt.Fprintf(b, "  DNS: %s\n", strings.Join(p.DNS.Servers, ", "))
	}
}

// Summary is the one-line description of a live config, used for the editor's
// adapter picker.
func (l LiveConfig) Summary() string {
	if len(l.Addresses) == 0 {
		return "no IPv4 address"
	}
	parts := make([]string, 0, len(l.Addresses))
	for _, a := range l.Addresses {
		parts = append(parts, a.String())
	}
	s := strings.Join(parts, ", ")
	if l.DHCP {
		s += " (DHCP)"
	}
	return s
}