package matrix

import (
	"fmt"
	"net/netip"
	"strings"
	"testing"

	"housecarl/internal/api"
	"housecarl/internal/model"
)

func state() *model.State {
	st := model.NewState()
	st.Zones = []*model.Zone{
		{ID: 1, Name: "guest", Interfaces: []string{"eth2"}},
		{ID: 2, Name: "lan", Interfaces: []string{"eth1"}},
		{ID: 3, Name: "wan", Interfaces: []string{"wan"}, External: true},
	}
	st.Sets = []*model.AddressSet{{ID: 4, Name: "admins", Entries: []string{"192.168.1.0/28"}}}
	pos := 0.0
	rule := func(r model.Rule) {
		pos++
		r.ID, r.Position = int64(10+pos), pos
		st.Rules = append(st.Rules, &r)
	}
	rule(model.Rule{Chain: "input", Match: model.Match{Sources: []string{"admins"}, Services: []string{"ssh"}}, Action: "accept", Comment: "SSH"})
	rule(model.Rule{Chain: "input", Match: model.Match{InZones: []string{"lan", "guest"}, Services: []string{"dns"}}, Action: "accept"})
	rule(model.Rule{Chain: "forward", Match: model.Match{InZones: []string{"lan"}, OutZones: []string{"wan"}}, Action: "accept", Comment: "LAN out"})
	rule(model.Rule{Chain: "forward", Match: model.Match{InZones: []string{"guest"}, OutZones: []string{"wan"}, Services: []string{"http", "https"}}, Action: "accept"})
	rule(model.Rule{Chain: "forward", Match: model.Match{InZones: []string{"wan"}}, Action: "drop", Comment: "nothing in"})
	rule(model.Rule{Chain: "forward", Match: model.Match{InZones: []string{"lan"}}, CtState: []string{"established"}, Action: "drop"}) // not for new
	rule(model.Rule{Chain: "output", Match: model.Match{OutZones: []string{"wan"}}, Action: "drop", Disabled: true})
	st.Forwards = []*model.PortForward{{ID: 30, Name: "web", Protocols: []string{"tcp"}, Ports: "443", To: "192.168.1.10"}}
	st.Settings.Builtins.MSSClamp = true
	return st
}

func find(m api.Matrix, from, to string) api.MatrixCell {
	for _, c := range m.Cells {
		if c.From == from && c.To == to {
			return c
		}
	}
	return api.MatrixCell{}
}

func TestMatrix(t *testing.T) {
	m := Build(state())
	if strings.Join(m.Zones, ",") != "guest,lan,wan" || len(m.Cells) != 3*3+3+3 {
		t.Fatalf("zones %v, %d cells", m.Zones, len(m.Cells))
	}
	for _, c := range []struct {
		from, to, verdict, decided string
		exceptions                 int
	}{
		{"lan", "wan", "allowed", "rule forward #13 (LAN out)", 0},
		{"guest", "wan", "blocked", "forward policy", 1},              // only web
		{"wan", "lan", "blocked", "rule forward #15 (nothing in)", 2}, // antispoof, port forwards come first
		{"lan", "guest", "blocked", "forward policy", 0},              // the established-only rule is no exception
		{"lan", Firewall, "blocked", "input policy", 4},               // icmpv6, ping, ssh from admins, dns
		{"wan", Firewall, "blocked", "input policy", 4},               // antispoof, icmpv6, dhcpv6, ssh from admins
		{Firewall, "wan", "allowed", "output policy", 0},              // the drop is disabled
	} {
		got := find(m, c.from, c.to)
		if got.Verdict != c.verdict || got.DecidedBy != c.decided || len(got.Exceptions) != c.exceptions {
			t.Errorf("%s → %s: %s by %s, %d exceptions %+v; want %s by %s, %d", c.from, c.to, got.Verdict, got.DecidedBy, len(got.Exceptions), got.Exceptions, c.verdict, c.decided, c.exceptions)
		}
	}
	g := find(m, "guest", "wan").Exceptions[0]
	if g.Verdict != "allowed" || g.What != "http, https" || g.RuleID != 14 {
		t.Errorf("the guest exception: %+v", g)
	}
	if e := find(m, "wan", "lan").Exceptions; e[0].Label != "built-in: antispoof" || e[1].Label != "port forwards" {
		t.Errorf("wan → lan exceptions: %+v", e)
	}
	if _, ok := Cell(state(), Options{}, "lan", "nowhere"); ok {
		t.Error("an unknown zone")
	}
}

// Rules whose addresses all live behind another zone are left out of a
// pair; routed (unknown) networks, and mixed lists, stay.
func TestConnected(t *testing.T) {
	st := state()
	st.Sets = append(st.Sets, &model.AddressSet{ID: 5, Name: "guest_net", Entries: []string{"192.168.2.0/24"}},
		&model.AddressSet{ID: 6, Name: "mixed", Entries: []string{"192.168.2.0/24", "10.20.30.0/24"}})
	st.Rules = append(st.Rules,
		&model.Rule{ID: 40, Chain: "forward", Position: 10, Match: model.Match{Sources: []string{"guest_net"}}, Action: "drop", Comment: "guests"},
		&model.Rule{ID: 41, Chain: "forward", Position: 11, Match: model.Match{Destinations: []string{"192.168.2.5"}}, Action: "accept", Comment: "to a guest"},
		&model.Rule{ID: 42, Chain: "forward", Position: 12, Match: model.Match{Sources: []string{"mixed"}}, Action: "drop", Comment: "mixed"})
	o := Options{Connected: map[netip.Prefix]string{netip.MustParsePrefix("192.168.1.0/24"): "lan", netip.MustParsePrefix("192.168.2.0/24"): "guest"}}
	ids := func(c api.MatrixCell) []int64 {
		var out []int64
		for _, e := range c.Exceptions {
			out = append(out, e.RuleID)
		}
		return out
	}
	lanWan, _ := Cell(st, o, "lan", "wan")
	if fmt.Sprint(ids(lanWan)) != "[]" {
		t.Errorf("lan → wan: %v", ids(lanWan)) // decided by "LAN out" before the others anyway
	}
	lanGuest, _ := Cell(st, o, "lan", "guest")
	if fmt.Sprint(ids(lanGuest)) != "[41 42]" {
		t.Errorf("lan → guest: %v", ids(lanGuest)) // not "guests": their addresses are guest's
	}
	guestLan, _ := Cell(st, o, "guest", "lan")
	if fmt.Sprint(ids(guestLan)) != "[40 42]" {
		t.Errorf("guest → lan: %v", ids(guestLan)) // not "to a guest": it is in guest, not lan
	}
}