package checker

import (
	"context"
	"encoding/json"
	"net"
	"strings"
	"testing"
	"time"

	sdk "git.happydns.org/checker-sdk-go/checker"
)

func TestIsValidHostname(t *testing.T) {
	good := []string{"example.com", "mx-1.example.com", "a.b.c.d", "MX.EXAMPLE.COM", "1.2.3.4"}
	for _, s := range good {
		if !isValidHostname(s) {
			t.Errorf("expected %q valid", s)
		}
	}
	bad := []string{
		"", "a b.com", "a\r\nb.com", "a\nb.com", "<bracket>.com",
		"under_score.com", "a@b.com", "spaces .com", strings.Repeat("a", 254),
	}
	for _, s := range bad {
		if isValidHostname(s) {
			t.Errorf("expected %q invalid", s)
		}
	}
}

func TestIsValidMailbox(t *testing.T) {
	good := []string{"a@b.com", "user.name+tag@mx.example.com", "postmaster@example.org"}
	for _, s := range good {
		if !isValidMailbox(s) {
			t.Errorf("expected %q valid", s)
		}
	}
	bad := []string{
		"",
		"@example.com",
		"a@",
		"a b@example.com",        // space in local
		"a\r\n@example.com",      // CRLF
		"a<b>@example.com",       // bracket in local
		"a,b@example.com",        // comma in local
		"\"quoted\"@example.com", // quoted local
		"a@with space.com",
		"a@<bracket>.com",
		strings.Repeat("a", 65) + "@example.com", // too-long local
	}
	for _, s := range bad {
		if isValidMailbox(s) {
			t.Errorf("expected %q invalid", s)
		}
	}
}

func TestCollect_RejectsInvalidDomain(t *testing.T) {
	p := &smtpProvider{}
	_, err := p.Collect(context.Background(), sdk.CheckerOptions{"domain": "evil\r\nMAIL FROM:<>"})
	if err == nil || !strings.Contains(err.Error(), "invalid domain") {
		t.Errorf("expected invalid-domain error, got %v", err)
	}
}

func TestCollect_RejectsInvalidHELO(t *testing.T) {
	p := &smtpProvider{}
	_, err := p.Collect(context.Background(), sdk.CheckerOptions{
		"domain":    "example.com",
		"helo_name": "evil\r\nRSET",
	})
	if err == nil || !strings.Contains(err.Error(), "invalid helo_name") {
		t.Errorf("expected invalid-helo error, got %v", err)
	}
}

func TestCollect_RewritesInvalidProbeAddress(t *testing.T) {
	p := &smtpProvider{}
	body := json.RawMessage(`{"mx":[{"Preference":0,"Mx":"."}]}`) // null MX → returns immediately
	out, err := p.Collect(context.Background(), sdk.CheckerOptions{
		"domain":             "example.com",
		"service":            body,
		"timeout":            1.0,
		"test_probe_address": "evil\r\nMAIL FROM:<x>",
	})
	if err != nil {
		t.Fatalf("collect: %v", err)
	}
	if !out.(*SMTPData).MX.NullMX {
		t.Error("expected null MX path")
	}
}

func TestSplitMail_MoreCases(t *testing.T) {
	cases := []struct {
		in            string
		ok            bool
		domain, local string
	}{
		{"a@b.com", true, "b.com", "a"},
		{"a@b@c.com", true, "c.com", "a@b"}, // last @ wins
		{"", false, "", ""},
		{"@", false, "", ""},
	}
	for _, c := range cases {
		d, l, ok := splitMail(c.in)
		if ok != c.ok || d != c.domain || l != c.local {
			t.Errorf("splitMail(%q) = (%q,%q,%v), want (%q,%q,%v)", c.in, d, l, ok, c.domain, c.local, c.ok)
		}
	}
}

func TestComputeCoverage_Empty(t *testing.T) {
	d := &SMTPData{}
	computeCoverage(d)
	if d.Coverage.AnyReachable {
		t.Errorf("empty endpoints should not be reachable")
	}
}

func TestComputeCoverage_AllPath(t *testing.T) {
	yes := true
	d := &SMTPData{
		Endpoints: []EndpointProbe{
			{IP: "1.2.3.4", IsIPv6: false, TCPConnected: true, BannerReceived: true, EHLOReceived: true, STARTTLSUpgraded: true, NullSenderAccepted: &yes, PostmasterAccepted: &yes},
			{IP: "2001:db8::1", IsIPv6: true, TCPConnected: true, BannerReceived: true, EHLOReceived: true, STARTTLSUpgraded: true, NullSenderAccepted: &yes, PostmasterAccepted: &yes},
		},
	}
	computeCoverage(d)
	c := d.Coverage
	if !c.HasIPv4 || !c.HasIPv6 || !c.AnyReachable || !c.AnyBanner || !c.AnyEHLO || !c.AnySTARTTLS || !c.AllSTARTTLS || !c.AllAcceptMail {
		t.Errorf("expected all coverage flags set, got %+v", c)
	}
}

func TestComputeCoverage_PartialSTARTTLS(t *testing.T) {
	yes := true
	d := &SMTPData{
		Endpoints: []EndpointProbe{
			{IP: "1.2.3.4", TCPConnected: true, BannerReceived: true, EHLOReceived: true, STARTTLSUpgraded: true, NullSenderAccepted: &yes, PostmasterAccepted: &yes},
			{IP: "1.2.3.5", TCPConnected: true, BannerReceived: true, EHLOReceived: true, STARTTLSUpgraded: false, NullSenderAccepted: &yes, PostmasterAccepted: &yes},
		},
	}
	computeCoverage(d)
	if !d.Coverage.AnySTARTTLS {
		t.Error("any STARTTLS expected")
	}
	if d.Coverage.AllSTARTTLS {
		t.Error("not all STARTTLS")
	}
}

func TestComputeCoverage_RejectedMailFlipsAccept(t *testing.T) {
	no := false
	yes := true
	d := &SMTPData{
		Endpoints: []EndpointProbe{
			{IP: "1.2.3.4", TCPConnected: true, BannerReceived: true, EHLOReceived: true, STARTTLSUpgraded: true, NullSenderAccepted: &no, PostmasterAccepted: &yes},
		},
	}
	computeCoverage(d)
	if d.Coverage.AllAcceptMail {
		t.Error("AllAcceptMail should be false when null sender rejected")
	}
}

func TestComputeCoverage_NoEHLOFlipsAccept(t *testing.T) {
	d := &SMTPData{
		Endpoints: []EndpointProbe{
			{IP: "1.2.3.4", TCPConnected: true, BannerReceived: true, EHLOReceived: false},
		},
	}
	computeCoverage(d)
	if d.Coverage.AllAcceptMail {
		t.Error("no EHLO must drop AllAcceptMail")
	}
}

func TestParseServiceBody_FullEnvelope(t *testing.T) {
	type mxitem struct {
		Hdr        struct{ Name string } `json:"Hdr"`
		Preference uint16
		Mx         string
	}
	body := struct {
		MXs []mxitem `json:"mx"`
	}{
		MXs: []mxitem{
			{Preference: 10, Mx: "mx1.example.com."},
			{Preference: 20, Mx: "mx2.example.com."},
		},
	}
	envelope := struct {
		Type    string          `json:"_svctype"`
		Service json.RawMessage `json:"Service"`
	}{Type: "svcs.MXs"}
	envelope.Service, _ = json.Marshal(body)
	raw, _ := json.Marshal(envelope)

	out := parseServiceBody(raw)
	if len(out) != 2 {
		t.Fatalf("got %d", len(out))
	}
	if out[0].Preference != 10 || out[0].Target != "mx1.example.com." {
		t.Errorf("[0]: %+v", out[0])
	}
}

func TestParseServiceBody_BareBody(t *testing.T) {
	raw := json.RawMessage(`{"mx":[{"Preference":5,"Mx":"mx.example.com."}]}`)
	out := parseServiceBody(raw)
	if len(out) != 1 || out[0].Preference != 5 {
		t.Errorf("got %+v", out)
	}
}

func TestParseServiceBody_BadJSON(t *testing.T) {
	if got := parseServiceBody(json.RawMessage(`not json`)); got != nil {
		t.Errorf("expected nil, got %+v", got)
	}
}

func TestParseServiceBody_NoMX(t *testing.T) {
	raw := json.RawMessage(`{"mx":[]}`)
	out := parseServiceBody(raw)
	if out == nil {
		t.Errorf("empty array should yield empty slice, not nil")
	}
	if len(out) != 0 {
		t.Errorf("got %+v", out)
	}
}

func TestLookupMX_NXDomainBecomesEmpty(t *testing.T) {
	// Use a TLD-style label that fails fast and cleanly. We rely on the
	// system resolver returning IsNotFound for invalid.example.invalid;
	// if the local resolver is unusual, the test is skipped.
	r := &net.Resolver{}
	out, err := lookupMX(context.Background(), r, "invalid.example.invalid")
	if err != nil {
		t.Skipf("resolver returned a different error: %v", err)
	}
	if out != nil {
		t.Errorf("expected nil for NXDOMAIN, got %+v", out)
	}
}

func TestCollect_RejectsEmptyDomain(t *testing.T) {
	p := &smtpProvider{}
	_, err := p.Collect(context.Background(), sdk.CheckerOptions{"domain": "  "})
	if err == nil || !strings.Contains(err.Error(), "domain is required") {
		t.Errorf("expected domain-required error, got %v", err)
	}
}

func TestCollect_NullMXFromService(t *testing.T) {
	p := &smtpProvider{}
	body := json.RawMessage(`{"mx":[{"Preference":0,"Mx":"."}]}`)
	out, err := p.Collect(context.Background(), sdk.CheckerOptions{
		"domain":  "example.com",
		"service": body,
		"timeout": 1.0,
	})
	if err != nil {
		t.Fatalf("collect: %v", err)
	}
	d, ok := out.(*SMTPData)
	if !ok {
		t.Fatalf("type: %T", out)
	}
	if !d.MX.NullMX {
		t.Errorf("expected NullMX=true, got %+v", d.MX)
	}
	if len(d.Endpoints) != 0 {
		t.Errorf("null MX should not probe, got %d endpoints", len(d.Endpoints))
	}
}

func TestCollect_RewritesProbeToAvoidLocalDomain(t *testing.T) {
	// Use a tiny timeout so the probe attempt against the bogus IP
	// fails fast; we only assert on the rewriting behavior, which
	// happens before any network call.
	p := &smtpProvider{}
	body := json.RawMessage(`{"mx":[{"Preference":10,"Mx":"127.255.255.255"}]}`) // unlikely to be an MX target
	opts := sdk.CheckerOptions{
		"domain":             "example.com",
		"service":            body,
		"timeout":            1.0,
		"test_probe_address": "victim@example.com", // same domain → must be rewritten
		"test_open_relay":    false,
		"test_null_sender":   false,
		"test_postmaster":    false,
	}
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	out, err := p.Collect(ctx, opts)
	if err != nil {
		t.Fatalf("collect: %v", err)
	}
	d := out.(*SMTPData)
	for _, ep := range d.Endpoints {
		if strings.Contains(ep.OpenRelayRecipient, "example.com") {
			t.Errorf("probe recipient leaked into the local domain: %q", ep.OpenRelayRecipient)
		}
	}
}