package api

import (
	"context"
	"encoding/xml"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

// testClient returns a Client pointed at srv, with the request-rate floor
// removed so tests do not sleep.
func testClient(srv *httptest.Server) *Client {
	return New(
		Credentials{User: "u", Password: "p", Context: "10"},
		WithEndpoint(srv.URL),
		WithInterval(time.Microsecond),
	)
}

// respond builds a server that returns body for every request and records the
// last request it saw.
func respond(t *testing.T, body string) (*httptest.Server, *Request) {
	t.Helper()
	var last Request
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		raw, err := io.ReadAll(r.Body)
		if err != nil {
			t.Errorf("read body: %v", err)
		}
		if err := xml.Unmarshal(raw, &last); err != nil {
			t.Errorf("server could not parse request %q: %v", raw, err)
		}
		w.Header().Set("Content-Type", "application/xml")
		// Every gateway answer, error or not, is HTTP 200. The tests must not
		// rely on this being different for failures.
		_, _ = io.WriteString(w, body)
	}))
	t.Cleanup(srv.Close)
	return srv, &last
}

func TestZonesParsesListResponse(t *testing.T) {
	// Shape from the Zone list documentation, task 0205.
	body := `<?xml version="1.0" encoding="UTF-8"?>
<response>
  <result>
    <data>
      <summary>2</summary>
      <zone>
        <name>example.com</name>
        <system_ns>nsa4.schlundtech.de</system_ns>
        <domainsafe>0</domainsafe>
      </zone>
      <zone>
        <name>example.org</name>
        <system_ns>nsb4.schlundtech.de</system_ns>
        <domainsafe>0</domainsafe>
      </zone>
    </data>
    <status>
      <code>S0205</code>
      <text>Zone information was inquired successfully.</text>
      <type>success</type>
    </status>
  </result>
  <stid>20160218-app2-dev-2603</stid>
</response>`
	srv, req := respond(t, body)

	zones, err := testClient(srv).Zones(context.Background())
	if err != nil {
		t.Fatalf("Zones: %v", err)
	}
	if len(zones) != 2 {
		t.Fatalf("got %d zones, want 2", len(zones))
	}
	if zones[0].Name != "example.com" || zones[0].SystemNS != "nsa4.schlundtech.de" {
		t.Errorf("zone 0 = %+v", zones[0])
	}
	if req.Task[0].Code != TaskZoneInquire {
		t.Errorf("task code = %q, want %q", req.Task[0].Code, TaskZoneInquire)
	}
	if req.Auth.Context != "10" {
		t.Errorf("context = %q, want 10", req.Auth.Context)
	}
}

func TestZoneParsesRecords(t *testing.T) {
	// Shape from the HAR capture of the live portal, task 0205 with a name.
	body := `<?xml version="1.0" encoding="UTF-8"?>
<response>
  <result>
    <data>
      <zone>
        <name>example.com</name>
        <origin>example.com</origin>
        <system_ns>nsa4.schlundtech.de</system_ns>
        <soa><ttl>3600</ttl><email>hostmaster@example.com</email></soa>
        <rr><name></name><type>TXT</type><value>v=spf1 -all</value><ttl>3600</ttl></rr>
        <rr><name>www</name><type>A</type><value>203.0.113.10</value><ttl>3600</ttl></rr>
        <rr><name>www</name><type>AAAA</type><value>2001:db8::1</value><ttl>3600</ttl></rr>
      </zone>
    </data>
    <status>
      <code>S0205</code>
      <text>Zonen-Informationen wurden erfolgreich ermittelt.</text>
      <type>success</type>
    </status>
  </result>
  <stid>20261001-18bbc3ffa605f6fd032405faebe80a7c</stid>
</response>`
	srv, _ := respond(t, body)
	c := testClient(srv)

	zone, err := c.Zone(context.Background(), "example.com")
	if err != nil {
		t.Fatalf("Zone: %v", err)
	}
	if zone.SystemNS != "nsa4.schlundtech.de" {
		t.Errorf("system_ns = %q", zone.SystemNS)
	}
	if len(zone.RRs) != 3 {
		t.Fatalf("got %d records, want 3", len(zone.RRs))
	}
	// The apex is the empty name.
	if zone.RRs[0].Name != "" || zone.RRs[0].Type != "TXT" {
		t.Errorf("record 0 = %+v", zone.RRs[0])
	}
	if zone.RRs[0].TTL != 3600 {
		t.Errorf("ttl = %d, want 3600", zone.RRs[0].TTL)
	}

	txt, err := c.Records(context.Background(), "example.com", "txt")
	if err != nil {
		t.Fatalf("Records: %v", err)
	}
	if len(txt) != 1 || txt[0].Type != "TXT" {
		t.Errorf("txt filter returned %+v", txt)
	}
}

// The gateway answers HTTP 200 for a bad password. A client that trusted the
// status code would report success here.
func TestErrorIsNotTakenFromHTTPStatus(t *testing.T) {
	body := `<?xml version="1.0" encoding="UTF-8"?>
<response><result>
  <msg>
    <text>User does not exist or password incorrect.</text>
    <code>EF00202</code>
    <type>error</type>
    <object><type>user</type><value>u</value></object>
  </msg>
  <status><code>E00000</code><text>Errors occurred during processing.</text><type>error</type></status>
</result><stid>20261001-4f6ed18d77f91afa9c1ef8cbd4ac434d</stid></response>`
	srv, _ := respond(t, body)

	_, err := testClient(srv).Zones(context.Background())
	if err == nil {
		t.Fatal("expected an error, got nil: HTTP 200 was mistaken for success")
	}
	apiErr, ok := err.(*APIError)
	if !ok {
		t.Fatalf("error type = %T, want *APIError", err)
	}
	// The actionable code lives in msg, not in the generic status code.
	if apiErr.Code != "EF00202" {
		t.Errorf("code = %q, want EF00202", apiErr.Code)
	}
	if !strings.Contains(apiErr.Error(), "password incorrect") {
		t.Errorf("message = %q", apiErr.Error())
	}
	if apiErr.Stid == "" {
		t.Error("stid was dropped, it is what support asks for")
	}
}

// A non-2xx status is a routing problem, and must not be reported as a task
// error with a gateway code.
func TestNon2xxIsReportedAsRoutingError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.WriteHeader(http.StatusNotFound)
		_, _ = io.WriteString(w, "<html>404 Not Found</html>")
	}))
	t.Cleanup(srv.Close)

	_, err := testClient(srv).Zones(context.Background())
	if err == nil {
		t.Fatal("expected an error for HTTP 404")
	}
	if _, ok := err.(*APIError); ok {
		t.Errorf("HTTP 404 was wrapped as an APIError: %v", err)
	}
	if !strings.Contains(err.Error(), "404") {
		t.Errorf("message = %q, want it to mention 404", err)
	}
}

func TestSetRecordsRemovesThenAdds(t *testing.T) {
	// First call answers the zone read, second the update.
	zoneBody := `<?xml version="1.0" encoding="UTF-8"?>
<response><result><data><zone>
  <name>example.com</name>
  <system_ns>nsa4.schlundtech.de</system_ns>
  <rr><name></name><type>TXT</type><value>old-a</value><ttl>600</ttl></rr>
  <rr><name></name><type>TXT</type><value>old-b</value><ttl>600</ttl></rr>
  <rr><name>www</name><type>A</type><value>203.0.113.1</value><ttl>300</ttl></rr>
</zone></data><status><code>S0205</code><type>success</type></status></result></response>`
	updateBody := `<?xml version="1.0" encoding="UTF-8"?>
<response><result>
  <msg><text>Zone was updated successfully on the name server.</text><code>0202001</code>
    <type>success</type><object><type>zone</type><value>example.com</value></object></msg>
  <status><code>S0202001</code><text>Bulk zone update completed successfully.</text><type>success</type></status>
</result><stid>20130906-app1-test-7072</stid></response>`

	var seen []Request
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		raw, _ := io.ReadAll(r.Body)
		var req Request
		if err := xml.Unmarshal(raw, &req); err != nil {
			t.Errorf("parse request: %v", err)
		}
		seen = append(seen, req)
		w.Header().Set("Content-Type", "application/xml")
		body := zoneBody
		if req.Task[0].Code == TaskZoneUpdateBulk {
			body = updateBody
		}
		_, _ = io.WriteString(w, body)
	}))
	t.Cleanup(srv.Close)

	err := testClient(srv).SetRecords(context.Background(), "example.com", "@", "TXT", []string{"new"}, 0)
	if err != nil {
		t.Fatalf("SetRecords: %v", err)
	}
	if len(seen) != 2 {
		t.Fatalf("got %d requests, want 2 (read then update)", len(seen))
	}

	update := seen[1].Task[0]
	if update.Code != TaskZoneUpdateBulk {
		t.Errorf("task code = %q", update.Code)
	}
	if update.Zone == nil || update.Zone.SystemNS != "nsa4.schlundtech.de" {
		t.Fatalf("update zone = %+v, want the system_ns from the zone read", update.Zone)
	}
	if update.Default == nil {
		t.Fatal("update had no default block")
	}
	// Both old values go, in one task.
	if len(update.Default.RRRem) != 2 {
		t.Errorf("rr_rem count = %d, want 2", len(update.Default.RRRem))
	}
	if len(update.Default.RRAdd) != 1 {
		t.Fatalf("rr_add count = %d, want 1", len(update.Default.RRAdd))
	}
	add := update.Default.RRAdd[0]
	// @ must reach the gateway as the empty apex name.
	if add.Name != "" {
		t.Errorf("rr_add name = %q, want empty (the apex)", add.Name)
	}
	if add.Type != "TXT" || add.Value != "new" {
		t.Errorf("rr_add = %+v", add)
	}
	// TTL was not given, so the existing one is carried over.
	if add.TTL != 600 {
		t.Errorf("rr_add ttl = %d, want 600 inherited from the existing record", add.TTL)
	}
}

func TestSetRecordsPreservesGivenTTL(t *testing.T) {
	zoneBody := `<?xml version="1.0" encoding="UTF-8"?>
<response><result><data><zone><name>example.com</name><system_ns>ns1.example.com</system_ns>
  <rr><name></name><type>A</type><value>1.1.1.1</value><ttl>300</ttl></rr>
</zone></data><status><code>S0205</code><type>success</type></status></result></response>`
	okBody := `<response><result><status><code>S0202001</code><type>success</type></status></result></response>`

	var update *Task
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		raw, _ := io.ReadAll(r.Body)
		var req Request
		_ = xml.Unmarshal(raw, &req)
		body := zoneBody
		if req.Task[0].Code == TaskZoneUpdateBulk {
			update = &req.Task[0]
			body = okBody
		}
		w.Header().Set("Content-Type", "application/xml")
		_, _ = io.WriteString(w, body)
	}))
	t.Cleanup(srv.Close)

	if err := testClient(srv).SetRecords(context.Background(), "example.com", "@", "A", []string{"2.2.2.2"}, 120); err != nil {
		t.Fatalf("SetRecords: %v", err)
	}
	if update == nil || update.Default == nil || len(update.Default.RRAdd) != 1 {
		t.Fatalf("no update task was sent: %+v", update)
	}
	if got := update.Default.RRAdd[0].TTL; got != 120 {
		t.Errorf("rr_add ttl = %d, want the explicit 120", got)
	}
}

func TestDeleteWithoutValueRemovesEveryValue(t *testing.T) {
	zoneBody := `<?xml version="1.0" encoding="UTF-8"?>
<response><result><data><zone><name>example.com</name><system_ns>ns1.example.com</system_ns>
  <rr><name>www</name><type>A</type><value>1.1.1.1</value><ttl>300</ttl></rr>
  <rr><name>www</name><type>A</type><value>2.2.2.2</value><ttl>300</ttl></rr>
  <rr><name>mail</name><type>A</type><value>3.3.3.3</value><ttl>300</ttl></rr>
</zone></data><status><code>S0205</code><type>success</type></status></result></response>`
	okBody := `<response><result><status><code>S0202001</code><type>success</type></status></result></response>`

	var update *Task
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		raw, _ := io.ReadAll(r.Body)
		var req Request
		_ = xml.Unmarshal(raw, &req)
		body := zoneBody
		if req.Task[0].Code == TaskZoneUpdateBulk {
			update = &req.Task[0]
			body = okBody
		}
		w.Header().Set("Content-Type", "application/xml")
		_, _ = io.WriteString(w, body)
	}))
	t.Cleanup(srv.Close)

	if err := testClient(srv).DeleteRecords(context.Background(), "example.com", "www", "A", nil); err != nil {
		t.Fatalf("DeleteRecords: %v", err)
	}
	if update == nil || update.Default == nil {
		t.Fatal("no update task was sent")
	}
	// Only the two records at that name, not the unrelated one.
	if len(update.Default.RRRem) != 2 {
		t.Errorf("rr_rem count = %d, want 2", len(update.Default.RRRem))
	}
	if len(update.Default.RRAdd) != 0 {
		t.Errorf("a delete sent %d rr_add blocks", len(update.Default.RRAdd))
	}
}

func TestDeleteUnknownRecordIsRefusedLocally(t *testing.T) {
	zoneBody := `<?xml version="1.0" encoding="UTF-8"?>
<response><result><data><zone><name>example.com</name><system_ns>ns1.example.com</system_ns>
  <rr><name>www</name><type>A</type><value>1.1.1.1</value><ttl>300</ttl></rr>
</zone></data><status><code>S0205</code><type>success</type></status></result></response>`

	var updates int
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		raw, _ := io.ReadAll(r.Body)
		var req Request
		_ = xml.Unmarshal(raw, &req)
		if req.Task[0].Code == TaskZoneUpdateBulk {
			updates++
		}
		w.Header().Set("Content-Type", "application/xml")
		_, _ = io.WriteString(w, zoneBody)
	}))
	t.Cleanup(srv.Close)

	err := testClient(srv).DeleteRecords(context.Background(), "example.com", "@", "TXT", nil)
	if err == nil {
		t.Fatal("expected an error when nothing matches")
	}
	if updates != 0 {
		t.Errorf("an update was sent anyway (%d)", updates)
	}
}

func TestSetRecordsRejectsEmptyValues(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {
		t.Error("no request should be made")
	}))
	t.Cleanup(srv.Close)

	if err := testClient(srv).SetRecords(context.Background(), "example.com", "@", "TXT", nil, 0); err == nil {
		t.Fatal("expected an error for an empty value list")
	}
}

// The gateway rejects a body with a byte order mark, so the client must not
// send one.
func TestRequestHasNoBOM(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		raw, _ := io.ReadAll(r.Body)
		if len(raw) >= 3 && raw[0] == 0xEF && raw[1] == 0xBB && raw[2] == 0xBF {
			t.Errorf("request starts with a byte order mark: % X", raw[:3])
		}
		if ct := r.Header.Get("Content-Type"); !strings.HasPrefix(ct, "application/xml") {
			t.Errorf("Content-Type = %q", ct)
		}
		w.Header().Set("Content-Type", "application/xml")
		_, _ = io.WriteString(w, `<response><result><status><code>S0205</code><type>success</type></status></result></response>`)
	}))
	t.Cleanup(srv.Close)

	if _, err := testClient(srv).Zones(context.Background()); err != nil {
		t.Fatalf("Zones: %v", err)
	}
}

func TestUpdateFailureSurfacesTheGatewayCode(t *testing.T) {
	zoneBody := `<?xml version="1.0" encoding="UTF-8"?>
<response><result><data><zone><name>example.com</name><system_ns>ns1.example.com</system_ns>
</zone></data><status><code>S0205</code><type>success</type></status></result></response>`
	// EF02020 is the documented "no such zone exists".
	errBody := `<?xml version="1.0" encoding="UTF-8"?>
<response><result>
  <msg><text>No such zone exists.</text><code>EF02020</code><type>error</type>
    <object><type>zone</type><value>example.com</value></object></msg>
  <status><code>E00000</code><text>Errors occurred during processing.</text><type>error</type></status>
</result></response>`

	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		raw, _ := io.ReadAll(r.Body)
		var req Request
		_ = xml.Unmarshal(raw, &req)
		w.Header().Set("Content-Type", "application/xml")
		if req.Task[0].Code == TaskZoneUpdateBulk {
			_, _ = io.WriteString(w, errBody)
			return
		}
		_, _ = io.WriteString(w, zoneBody)
	}))
	t.Cleanup(srv.Close)

	err := testClient(srv).SetRecords(context.Background(), "example.com", "@", "A", []string{"1.2.3.4"}, 0)
	apiErr, ok := err.(*APIError)
	if !ok {
		t.Fatalf("error type = %T (%v), want *APIError", err, err)
	}
	if apiErr.Code != "EF02020" {
		t.Errorf("code = %q, want EF02020", apiErr.Code)
	}
	if !strings.Contains(apiErr.Object, "example.com") {
		t.Errorf("object = %q, want it to name the zone", apiErr.Object)
	}
}

// The Auth object documents token as an optional 2FA element. It must appear in
// the auth block when set, and be absent otherwise.
func TestTwoFactorTokenIsSerialised(t *testing.T) {
	for _, tc := range []struct {
		name  string
		token string
		want  bool
	}{
		{name: "without 2FA", token: "", want: false},
		{name: "with 2FA", token: "123456", want: true},
	} {
		t.Run(tc.name, func(t *testing.T) {
			srv, req := respond(t, `<response><result><status><code>S0205</code><type>success</type></status></result></response>`)
			c := New(
				Credentials{User: "u", Password: "p", Context: "10", Token: tc.token},
				WithEndpoint(srv.URL),
				WithInterval(time.Microsecond),
			)
			if _, err := c.Zones(context.Background()); err != nil {
				t.Fatalf("Zones: %v", err)
			}
			if got := req.Auth.Token != ""; got != tc.want {
				t.Errorf("auth token present = %v, want %v", got, tc.want)
			}
		})
	}
}