// Package vhost is a Fase 0.6 adapter around v1 network.VHostScanner which
// performs virtual host discovery on resolved IPs. Reveals additional
// hostnames sharing infrastructure with in-scope targets.
package vhost

import (
	"strings"
	"sync"
	"time"

	"god-eye/internal/eventbus"
	"god-eye/internal/module"
	"god-eye/internal/network"
	"god-eye/internal/store"
)

const ModuleName = "discovery.vhost"

type vhostModule struct{}

func Register() { module.Register(&vhostModule{}) }

func (*vhostModule) Name() string                   { return ModuleName }
func (*vhostModule) Phase() module.Phase            { return module.PhaseResolution }
func (*vhostModule) Consumes() []eventbus.EventType { return []eventbus.EventType{eventbus.EventDNSResolved} }
func (*vhostModule) Produces() []eventbus.EventType {
	return []eventbus.EventType{eventbus.EventSubdomainDiscovered}
}
func (*vhostModule) DefaultEnabled() bool { return false } // opt-in

func (*vhostModule) Run(mctx module.Context) error {
	if !mctx.Config.Bool("vhost_scan", false) {
		return nil
	}
	timeout := mctx.Config.Int("timeout", 10)
	target := mctx.Target

	hosts := mctx.Store.All(mctx.Ctx)
	seenIP := make(map[string]struct{})
	for _, h := range hosts {
		for _, ip := range h.IPs {
			seenIP[ip] = struct{}{}
		}
	}

	scanner := network.NewVHostScanner(timeout)
	var wg sync.WaitGroup
	for ip := range seenIP {
		ip := ip
		if mctx.Ctx.Err() != nil {
			break
		}
		wg.Add(1)
		go func() {
			defer wg.Done()
			res := scanner.DiscoverVHosts(mctx.Ctx, ip)
			if res == nil {
				return
			}
			for _, h := range res.Domains {
				h = strings.ToLower(strings.TrimSpace(h))
				if h == "" || !strings.HasSuffix(h, target) {
					continue
				}
				_ = mctx.Store.Upsert(mctx.Ctx, h, func(sh *store.Host) {
					store.AddIPs(sh, []string{ip})
					store.AddDiscoveryMethod(sh, "vhost")
				})
				mctx.Bus.Publish(mctx.Ctx, eventbus.SubdomainDiscovered{
					EventMeta: eventbus.EventMeta{At: time.Now(), Source: ModuleName, Target: h},
					Subdomain: h,
					Method:    "vhost",
				})
			}
		}()
	}
	wg.Wait()
	return nil
}