package validate

import (
	"strings"
	"testing"

	"jarl/internal/dnsname"
	"jarl/internal/model"
	"jarl/internal/rr"
)

type builder struct {
	s  *model.State
	id int64
}

func newBuilder() *builder { return &builder{s: model.NewState()} }

func (b *builder) next() int64 { b.id++; return b.id }

func (b *builder) view(name string, clients ...string) *model.View {
	v := &model.View{ID: b.next(), Name: name, Position: len(b.s.Views), MatchClients: clients}
	b.s.Views[v.ID] = v
	return v
}

func (b *builder) zone(name string, view *model.View, typ string) *model.Zone {
	z := &model.Zone{ID: b.next(), Name: dnsname.Fqdn(name), Type: typ, DefaultTTL: 3600,
		SOA: model.SOA{MName: "ns1." + dnsname.Fqdn(name), RName: "hostmaster." + dnsname.Fqdn(name), Serial: 1, Refresh: 3600, Retry: 900, Expire: 1209600, Minimum: 300}}
	if view != nil {
		z.ViewID = view.ID
	}
	b.s.Zones[z.ID] = z
	return z
}

// primary creates a valid primary zone with NS and glue.
func (b *builder) primary(name string, view *model.View) *model.Zone {
	z := b.zone(name, view, model.ZonePrimary)
	b.rec(z, "@", "NS", "ns1")
	b.rec(z, "ns1", "A", "192.0.2.1")
	return z
}

func (b *builder) rec(z *model.Zone, name, typ, data string) *model.Record {
	owner, err := dnsname.Owner(name, z.Name)
	if err != nil {
		panic(err)
	}
	p, err := rr.Parse(z.Name, owner, typ, data)
	if err != nil {
		panic(name + " " + typ + " " + data + ": " + err.Error())
	}
	r := &model.Record{ID: b.next(), ZoneID: z.ID, Name: owner, Type: p.Type, Data: p.Data}
	b.s.Records[r.ID] = r
	return r
}

func (b *builder) opt(scope string, scopeID int64, name, value string) *model.Option {
	o := &model.Option{ID: b.next(), Scope: scope, ScopeID: scopeID, Name: name, Value: value}
	b.s.Options[o.ID] = o
	return o
}

func codes(ps []Problem, sev Severity) []string {
	var out []string
	for _, p := range ps {
		if p.Severity == sev {
			out = append(out, p.Code)
		}
	}
	return out
}

func hasCode(ps []Problem, code string) bool {
	for _, p := range ps {
		if p.Code == code {
			return true
		}
	}
	return false
}

func TestValidZoneIsClean(t *testing.T) {
	b := newBuilder()
	z := b.primary("example.com", nil)
	b.rec(z, "www", "A", "192.0.2.10")
	b.rec(z, "www", "AAAA", "2001:db8::10")
	b.rec(z, "@", "MX", "10 mail")
	b.rec(z, "mail", "A", "192.0.2.25")
	b.rec(z, "@", "TXT", "v=spf1 mx -all")
	b.rec(z, "_dmarc", "TXT", "v=DMARC1; p=none")
	b.rec(z, "ftp", "CNAME", "www")
	b.rec(z, "_sip._tcp", "SRV", "0 5 5060 www")
	b.rec(z, "*", "A", "192.0.2.99")
	b.rec(z, "sub", "NS", "ns.sub")
	b.rec(z, "ns.sub", "A", "192.0.2.53")
	b.rec(z, "sub", "DS", "12345 13 2 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef")
	rz := b.primary("2.0.192.in-addr.arpa", nil)
	rz.SOA.MName = "ns1.example.com."
	b.rec(rz, "10", "PTR", "www.example.com.")
	b.opt(model.ScopeOptions, 0, "recursion", "yes")
	b.opt(model.ScopeOptions, 0, "allow-recursion", "{ 192.168.0.0/16; localhost; }")
	ps := State(b.s, Options{})
	for _, p := range ps {
		if p.Severity != Info {
			t.Errorf("unexpected problem: %s (%s)", p, p.Code)
		}
	}
}

func TestRecordConflicts(t *testing.T) {
	cases := []struct {
		name  string
		build func(b *builder, z *model.Zone)
		code  string
		sev   Severity
	}{
		{"cname and A", func(b *builder, z *model.Zone) {
			b.rec(z, "www", "CNAME", "ns1")
			b.rec(z, "www", "A", "192.0.2.2")
		}, "cname_conflict", Error},
		{"two cnames", func(b *builder, z *model.Zone) {
			b.rec(z, "www", "CNAME", "ns1")
			b.rec(z, "www", "CNAME", "other.example.org.")
		}, "cname_multiple", Error},
		{"cname at apex", func(b *builder, z *model.Zone) { b.rec(z, "@", "CNAME", "other.example.org.") }, "cname_apex", Error},
		{"duplicate", func(b *builder, z *model.Zone) {
			b.rec(z, "x", "A", "192.0.2.2")
			b.rec(z, "x", "A", "192.0.2.2")
		}, "record_duplicate", Error},
		{"ttl mismatch", func(b *builder, z *model.Zone) {
			r := b.rec(z, "x", "A", "192.0.2.2")
			r.TTL = model.Ptr(uint32(60))
			b.rec(z, "x", "A", "192.0.2.3")
		}, "rrset_ttl_mismatch", Error},
		{"mx to cname", func(b *builder, z *model.Zone) {
			b.rec(z, "mail", "CNAME", "ns1")
			b.rec(z, "@", "MX", "10 mail")
		}, "mx_cname", Error},
		{"srv to cname", func(b *builder, z *model.Zone) {
			b.rec(z, "alias", "CNAME", "ns1")
			b.rec(z, "_sip._tcp", "SRV", "0 0 5060 alias")
		}, "srv_cname", Error},
		{"missing glue", func(b *builder, z *model.Zone) { b.rec(z, "sub", "NS", "ns.sub") }, "glue_missing", Error},
		{"apex ns without address", func(b *builder, z *model.Zone) { b.rec(z, "@", "NS", "ns2") }, "ns_no_address", Error},
		{"ds not at delegation", func(b *builder, z *model.Zone) {
			b.rec(z, "x", "DS", "12345 13 2 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef")
		}, "ds_not_at_delegation", Error},
		{"below dname", func(b *builder, z *model.Zone) {
			b.rec(z, "d", "DNAME", "other.example.org.")
			b.rec(z, "x.d", "A", "192.0.2.2")
		}, "below_dname", Error},
		{"occluded", func(b *builder, z *model.Zone) {
			b.rec(z, "sub", "NS", "ns.other.org.")
			b.rec(z, "www.sub", "A", "192.0.2.2")
		}, "occluded", Warning},
		{"cname loop", func(b *builder, z *model.Zone) {
			b.rec(z, "a", "CNAME", "b")
			b.rec(z, "b", "CNAME", "a")
		}, "cname_loop", Error},
		{"cname chain", func(b *builder, z *model.Zone) {
			b.rec(z, "a", "CNAME", "b")
			b.rec(z, "b", "CNAME", "ns1")
		}, "cname_chain", Warning},
		{"dangling cname", func(b *builder, z *model.Zone) { b.rec(z, "a", "CNAME", "nothing") }, "cname_dangling", Warning},
		{"null mx not alone", func(b *builder, z *model.Zone) {
			b.rec(z, "@", "MX", "0 .")
			b.rec(z, "@", "MX", "10 ns1")
		}, "null_mx_not_alone", Error},
		{"two spf", func(b *builder, z *model.Zone) {
			b.rec(z, "@", "TXT", "v=spf1 mx -all")
			b.rec(z, "@", "TXT", "v=spf1 a -all")
		}, "spf_multiple", Warning},
		{"mx target missing", func(b *builder, z *model.Zone) { b.rec(z, "@", "MX", "10 nomail") }, "target_no_address", Warning},
		{"ns to cname", func(b *builder, z *model.Zone) {
			b.rec(z, "nsalias", "CNAME", "ns1")
			b.rec(z, "@", "NS", "nsalias")
		}, "ns_cname", Error},
	}
	for _, c := range cases {
		b := newBuilder()
		z := b.primary("example.com", nil)
		c.build(b, z)
		ps := State(b.s, Options{})
		found := false
		for _, p := range ps {
			if p.Code == c.code && p.Severity == c.sev {
				found = true
			}
		}
		if !found {
			t.Errorf("%s: expected %s %s, got errors %v warnings %v", c.name, c.sev, c.code, codes(ps, Error), codes(ps, Warning))
		}
	}
}

func TestZoneRules(t *testing.T) {
	b := newBuilder()
	b.zone("empty.com", nil, model.ZonePrimary) // no NS
	b.zone("sec.com", nil, model.ZoneSecondary) // no primaries
	ps := State(b.s, Options{})
	if !hasCode(ps, "apex_ns_missing") || !hasCode(ps, "zone_missing_option") {
		t.Errorf("got %v", codes(ps, Error))
	}

	// Views: zones outside views are not allowed once views exist.
	b = newBuilder()
	b.primary("example.com", nil)
	b.view("internal", "192.168.0.0/16")
	ps = State(b.s, Options{})
	if !hasCode(ps, "zone_outside_view") {
		t.Errorf("zone outside view not reported: %v", codes(ps, Error))
	}

	// in-view must reference an earlier view.
	b = newBuilder()
	ext := b.view("external")
	in := b.view("internal", "10/8")
	b.primary("example.com", in)
	iv := b.zone("example.com", ext, model.ZoneInView)
	iv.InView = "internal"
	ps = State(b.s, Options{})
	if !hasCode(ps, "zone_inview_invalid") {
		t.Errorf("in-view order not checked: %v", codes(ps, Error))
	}
	if !hasCode(ps, "view_unreachable") {
		t.Errorf("unreachable view not reported: %v", codes(ps, Warning))
	}
	in.Position, ext.Position = 0, 1
	ps = State(b.s, Options{})
	if HasErrors(ps) {
		t.Errorf("valid in-view setup has errors: %v", Errors(ps))
	}
}

func TestACLsAndOptions(t *testing.T) {
	b := newBuilder()
	b.s.ACLs[1] = &model.ACL{ID: 1, Name: "lan", Elements: []string{"192.168.1.0/24", "!192.168.1.5", "missing", "key nokey"}}
	b.s.ACLs[2] = &model.ACL{ID: 2, Name: "a", Elements: []string{"b"}}
	b.s.ACLs[3] = &model.ACL{ID: 3, Name: "b", Elements: []string{"a"}}
	b.s.ACLs[4] = &model.ACL{ID: 4, Name: "any", Elements: []string{"10.0.0.0/8"}}
	b.s.ACLs[5] = &model.ACL{ID: 5, Name: "bad", Elements: []string{"10.0.0.1/8"}}
	b.id = 10
	b.opt(model.ScopeOptions, 0, "recursion", "maybe")
	b.opt(model.ScopeOptions, 0, "frobnicate", "yes")
	b.opt(model.ScopeOptions, 0, "allow-query", "{ lan; ghost; }")
	b.opt(model.ScopeOptions, 0, "allow-transfer", "{ key nope; }")
	b.opt(model.ScopeOptions, 0, "directory", `"/var/cache/bind"`)
	b.opt(model.ScopeOptions, 0, "directory", `"/tmp"`)
	b.opt(model.ScopeOptions, 0, "dnssec-validation", "sometimes")
	b.opt(model.ScopeTopLevel, 0, "acl", "x { any; }")
	ps := State(b.s, Options{})
	for _, want := range []string{"acl_ref_missing", "key_ref_missing", "acl_cycle", "acl_name_invalid", "acl_element_invalid", "option_value_invalid", "option_unknown", "option_duplicate", "option_managed"} {
		if !hasCode(ps, want) {
			t.Errorf("missing %s; got %v", want, codes(ps, Error))
		}
	}
	if !hasCode(ps, "acl_shadowed") {
		t.Errorf("shadowed element not reported: %v", codes(ps, Warning))
	}
	ps = State(b.s, Options{ExternalKeysUnknown: true})
	for _, p := range ps {
		if p.Code == "key_ref_missing" {
			t.Error("key refs reported despite ExternalKeysUnknown")
		}
	}
}

func TestSecurityLints(t *testing.T) {
	// allow-query any without allow-recursion: open resolver.
	b := newBuilder()
	b.primary("example.com", nil)
	b.opt(model.ScopeOptions, 0, "allow-query", "{ any; }")
	ps := State(b.s, Options{})
	if !hasCode(ps, "security_open_resolver") {
		t.Errorf("open resolver not detected: %v", codes(ps, Warning))
	}
	// Fixed by recursion no.
	b.opt(model.ScopeOptions, 0, "recursion", "no")
	if hasCode(State(b.s, Options{}), "security_open_resolver") {
		t.Error("open resolver reported with recursion no")
	}
	// Through an ACL that contains any.
	b = newBuilder()
	b.s.ACLs[100] = &model.ACL{ID: 100, Name: "everyone", Elements: []string{"any"}}
	b.opt(model.ScopeOptions, 0, "allow-recursion", "{ everyone; }")
	if !hasCode(State(b.s, Options{}), "security_open_resolver") {
		t.Error("open resolver via ACL not detected")
	}
	// Inside a view that only matches internal clients it's fine.
	b = newBuilder()
	v := b.view("internal", "192.168.0.0/16")
	b.opt(model.ScopeView, v.ID, "allow-recursion", "{ any; }")
	if hasCode(State(b.s, Options{}), "security_open_resolver") {
		t.Error("open resolver reported for internal-only view")
	}
	// Dynamic updates are rejected.
	b = newBuilder()
	z := b.primary("example.com", nil)
	b.opt(model.ScopeZone, z.ID, "allow-update", "{ key ddns; }")
	ps = State(b.s, Options{ExternalKeys: []string{"ddns"}})
	if !hasCode(ps, "dynamic_update_unsupported") {
		t.Errorf("allow-update not rejected: %v", codes(ps, Error))
	}
	b.s.Options[b.id].Value = "{ none; }"
	if hasCode(State(b.s, Options{}), "dynamic_update_unsupported") {
		t.Error("allow-update { none; } rejected")
	}
	// Open transfers.
	b.opt(model.ScopeZone, z.ID, "allow-transfer", "{ any; }")
	if !hasCode(State(b.s, Options{}), "security_open_transfer") {
		t.Error("open transfer not detected")
	}
}

func TestIntroduced(t *testing.T) {
	b := newBuilder()
	z := b.primary("example.com", nil)
	before := State(b.s, Options{})
	b.rec(z, "www", "CNAME", "ns1")
	b.rec(z, "www", "TXT", "x")
	after := State(b.s, Options{})
	intro := Introduced(before, after)
	if len(intro) == 0 || intro[0].Code != "cname_conflict" {
		t.Errorf("Introduced = %v", intro)
	}
	if len(Introduced(after, after)) != 0 {
		t.Error("same state introduced problems")
	}
}

func TestRecordLimit(t *testing.T) {
	b := newBuilder()
	z := b.primary("example.com", nil)
	for i := 0; i < 101; i++ {
		b.rec(z, "many", "TXT", strings.Repeat("x", i+1))
	}
	if !hasCode(State(b.s, Options{}), "rrset_too_large") {
		t.Error("RRset over 100 records not reported")
	}
	b.opt(model.ScopeOptions, 0, "max-records-per-type", "0")
	if hasCode(State(b.s, Options{}), "rrset_too_large") {
		t.Error("max-records-per-type 0 (unlimited) not honoured")
	}
}