package api_test

import (
	"bufio"
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"regexp"
	"strings"
	"testing"
	"time"

	"gitea.hansenits.com.au/hits/ExploreDNS/internal/config"
	"gitea.hansenits.com.au/hits/ExploreDNS/web/api"
)

// newTestServer starts a Server on a random port and returns it.
// The caller is responsible for calling srv.Shutdown.
func newTestServer(t *testing.T) *api.Server {
	t.Helper()
	srv := api.NewServer("127.0.0.1:0")
	if err := srv.Start(); err != nil {
		t.Fatalf("start server: %v", err)
	}
	return srv
}

func TestHealth(t *testing.T) {
	t.Setenv("FLY_REGION", "") // ensure region is absent regardless of host env
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/api/health")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("want 200, got %d", resp.StatusCode)
	}
	var body map[string]string
	if err := json.NewDecoder(resp.Body).Decode(&body); err != nil {
		t.Fatal(err)
	}
	if body["status"] != "ok" {
		t.Fatalf("want status=ok, got %q", body["status"])
	}
	if body["version"] != "dev" {
		t.Fatalf("want version=dev, got %q", body["version"])
	}
	if region, ok := body["region"]; ok {
		t.Fatalf("region should be omitted outside Fly, got %q", region)
	}
}

func TestHealthReportsFlyRegion(t *testing.T) {
	t.Setenv("FLY_REGION", "syd")
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/api/health")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	var body map[string]string
	if err := json.NewDecoder(resp.Body).Decode(&body); err != nil {
		t.Fatal(err)
	}
	if body["region"] != "syd" {
		t.Fatalf("want region=syd, got %q", body["region"])
	}
}

func TestHealthReportsStampedVersion(t *testing.T) {
	srv := api.NewServer("127.0.0.1:0")
	srv.SetVersion("v1.2.3")
	if err := srv.Start(); err != nil {
		t.Fatalf("start server: %v", err)
	}
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/api/health")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	var body map[string]string
	if err := json.NewDecoder(resp.Body).Decode(&body); err != nil {
		t.Fatal(err)
	}
	if body["version"] != "v1.2.3" {
		t.Fatalf("want version=v1.2.3, got %q", body["version"])
	}
}

func TestCORSDisabledByDefault(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	req, _ := http.NewRequest(http.MethodGet, "http://"+srv.Addr()+"/api/health", nil)
	req.Header.Set("Origin", "http://localhost:3000")
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if got := resp.Header.Get("Access-Control-Allow-Origin"); got != "" {
		t.Fatalf("CORS should be off by default, got origin header %q", got)
	}
}

func TestCORSPreflightWithConfiguredOrigin(t *testing.T) {
	t.Setenv("EXPLOREDNS_CORS_ORIGIN", "http://localhost:3000")
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	req, _ := http.NewRequest(http.MethodOptions, "http://"+srv.Addr()+"/api/health", nil)
	req.Header.Set("Origin", "http://localhost:3000")
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusNoContent {
		t.Fatalf("want 204, got %d", resp.StatusCode)
	}
	if got := resp.Header.Get("Access-Control-Allow-Origin"); got != "http://localhost:3000" {
		t.Fatalf("CORS origin header: %q", got)
	}
}

func TestStartTraversal_MissingDomain(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	body := bytes.NewBufferString(`{}`)
	resp, err := http.Post("http://"+srv.Addr()+"/api/traverse", "application/json", body)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusBadRequest {
		t.Fatalf("want 400, got %d", resp.StatusCode)
	}
}

func TestStartTraversal_InvalidType(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	body := bytes.NewBufferString(`{"domain":"example.com","type":"BOGUS"}`)
	resp, err := http.Post("http://"+srv.Addr()+"/api/traverse", "application/json", body)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusBadRequest {
		t.Fatalf("want 400, got %d", resp.StatusCode)
	}
}

func TestStartTraversal_ReturnsID(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	body := bytes.NewBufferString(`{"domain":"example.com","type":"A"}`)
	resp, err := http.Post("http://"+srv.Addr()+"/api/traverse", "application/json", body)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusAccepted {
		t.Fatalf("want 202, got %d", resp.StatusCode)
	}
	var start struct {
		ID     string `json:"id"`
		Status string `json:"status"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&start); err != nil {
		t.Fatal(err)
	}
	if start.ID == "" {
		t.Fatal("expected non-empty id")
	}
	if start.Status != "running" {
		t.Fatalf("want status=running, got %q", start.Status)
	}
}

func TestGetTraversal_NotFound(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/api/traverse/does-not-exist")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusNotFound {
		t.Fatalf("want 404, got %d", resp.StatusCode)
	}
}

func TestGetTraversal_Found(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	// Start a job.
	startBody := bytes.NewBufferString(`{"domain":"example.com","type":"A"}`)
	startResp, err := http.Post("http://"+srv.Addr()+"/api/traverse", "application/json", startBody)
	if err != nil {
		t.Fatal(err)
	}
	defer startResp.Body.Close()

	var start struct {
		ID string `json:"id"`
	}
	if err := json.NewDecoder(startResp.Body).Decode(&start); err != nil {
		t.Fatal(err)
	}

	// Poll for it.
	resp, err := http.Get("http://" + srv.Addr() + "/api/traverse/" + start.ID)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("want 200, got %d", resp.StatusCode)
	}
	var job struct {
		ID     string `json:"id"`
		Status string `json:"status"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&job); err != nil {
		t.Fatal(err)
	}
	if job.ID != start.ID {
		t.Fatalf("id mismatch: %q vs %q", job.ID, start.ID)
	}
}

func TestGetServers_NotFound(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/api/traverse/does-not-exist/servers")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusNotFound {
		t.Fatalf("want 404, got %d", resp.StatusCode)
	}
}

// TestGetServers_AvailableAfterCompletion drives a full job through the API:
// the servers endpoint answers 202 pending while the traversal/fingerprinting
// is in flight and the fingerprinted list once everything finished.
func TestGetServers_AvailableAfterCompletion(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	startBody := bytes.NewBufferString(`{"domain":"example.com","type":"A"}`)
	startResp, err := http.Post("http://"+srv.Addr()+"/api/traverse", "application/json", startBody)
	if err != nil {
		t.Fatal(err)
	}
	defer startResp.Body.Close()

	var start struct {
		ID string `json:"id"`
	}
	if err := json.NewDecoder(startResp.Body).Decode(&start); err != nil {
		t.Fatal(err)
	}

	deadline := time.Now().Add(90 * time.Second)
	for {
		resp, err := http.Get("http://" + srv.Addr() + "/api/traverse/" + start.ID + "/servers")
		if err != nil {
			t.Fatal(err)
		}
		body, err := io.ReadAll(resp.Body)
		resp.Body.Close()
		if err != nil {
			t.Fatal(err)
		}

		switch resp.StatusCode {
		case http.StatusAccepted:
			var pending struct {
				Status string `json:"status"`
			}
			if err := json.Unmarshal(body, &pending); err != nil {
				t.Fatalf("pending body: %v (%s)", err, body)
			}
			if pending.Status != "pending" {
				t.Fatalf("want status=pending, got %q", pending.Status)
			}
		case http.StatusOK:
			var done struct {
				Status  string `json:"status"`
				Servers []struct {
					Name    string `json:"name"`
					IP      string `json:"ip"`
					Version string `json:"version"`
				} `json:"servers"`
			}
			if err := json.Unmarshal(body, &done); err != nil {
				t.Fatalf("servers body: %v (%s)", err, body)
			}
			if done.Status != "complete" {
				t.Fatalf("want status=complete, got %q", done.Status)
			}
			if done.Servers == nil {
				t.Fatalf("servers key missing or null: %s", body)
			}
			return
		default:
			t.Fatalf("unexpected status %d: %s", resp.StatusCode, body)
		}

		if time.Now().After(deadline) {
			t.Fatal("timed out waiting for servers to become available")
		}
		time.Sleep(250 * time.Millisecond)
	}
}

func TestStreamTraversal_NotFound(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/api/traverse/nope/stream")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusNotFound {
		t.Fatalf("want 404, got %d", resp.StatusCode)
	}
}

func TestStreamTraversal_ContentType(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	// Start a job.
	startBody := bytes.NewBufferString(`{"domain":"example.com","type":"A"}`)
	startResp, err := http.Post("http://"+srv.Addr()+"/api/traverse", "application/json", startBody)
	if err != nil {
		t.Fatal(err)
	}
	defer startResp.Body.Close()

	var start struct {
		ID string `json:"id"`
	}
	if err := json.NewDecoder(startResp.Body).Decode(&start); err != nil {
		t.Fatal(err)
	}

	// Open SSE stream.
	resp, err := http.Get("http://" + srv.Addr() + "/api/traverse/" + start.ID + "/stream")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if ct := resp.Header.Get("Content-Type"); !strings.HasPrefix(ct, "text/event-stream") {
		t.Fatalf("want text/event-stream, got %q", ct)
	}

	// Read until we get the done event or timeout.
	done := make(chan struct{})
	go func() {
		defer close(done)
		scanner := bufio.NewScanner(resp.Body)
		for scanner.Scan() {
			line := scanner.Text()
			if strings.HasPrefix(line, "event: done") {
				return
			}
		}
	}()

	select {
	case <-done:
	case <-time.After(30 * time.Second):
		t.Fatal("timed out waiting for SSE done event")
	}
}

func TestStaticSPA_Index(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("want 200, got %d", resp.StatusCode)
	}
}

// TestStaticSPA_TypeOptions asserts the SPA type dropdown offers exactly the
// query types config.ParseQueryType accepts.
func TestStaticSPA_TypeOptions(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}
	page := string(body)

	re := regexp.MustCompile(`<option>([A-Z]+)</option>`)
	var got []string
	for _, m := range re.FindAllStringSubmatch(page, -1) {
		got = append(got, m[1])
	}
	want := []string{"A", "AAAA", "NS", "CNAME", "MX", "TXT", "SOA", "PTR", "ANY"}
	if len(got) != len(want) {
		t.Fatalf("type options = %v, want %v", got, want)
	}
	for i, typ := range want {
		if got[i] != typ {
			t.Fatalf("type options = %v, want %v", got, want)
		}
		if _, err := config.ParseQueryType(typ); err != nil {
			t.Fatalf("option %s rejected by ParseQueryType: %v", typ, err)
		}
	}
}

// TestStaticSPA_DetailTree asserts the SPA ships the live detail tree with
// its resolve-subtree toggle markup, plus the raw-log fallback feed so the
// old flat progress view is still reachable for debugging.
func TestStaticSPA_DetailTree(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}
	page := string(body)

	for _, want := range []string{
		`id="detailTree"`,   // detail-tree container
		`resolve-toggle`,    // per-node show/hide resolve markup
		`show resolve`,      // toggle wording mirrors dns.squish.net
		`id="progressFeed"`, // raw-log fallback feed still present
		`id="rawToggle"`,    // toggle that reveals it
	} {
		if !strings.Contains(page, want) {
			t.Errorf("index.html missing %q", want)
		}
	}
}

// TestStaticSPA_ServersSection asserts the SPA ships the server map/table
// section: Leaflet lazy-loaded from unpkg, geojs.io client-side geolocation,
// and the reference-style table headings.
func TestStaticSPA_ServersSection(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}
	page := string(body)

	for _, want := range []string{
		`unpkg.com/leaflet@1.9`, // map library CDN
		`get.geojs.io`,          // client-side geolocation service
		`id="serversCard"`,
		`id="serverMap"`,
		`<th>Country</th><th>City</th><th>Servers</th><th>Software guess</th>`,
		`/servers`, // fetches the servers endpoint
	} {
		if !strings.Contains(page, want) {
			t.Errorf("index.html missing %q", want)
		}
	}
}

func TestStaticSPA_FallbackToIndex(t *testing.T) {
	srv := newTestServer(t)
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get("http://" + srv.Addr() + "/some/spa/route")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("want 200 (SPA fallback), got %d", resp.StatusCode)
	}
}

// TestHandlerUnit uses httptest.NewRecorder for fast unit tests without
// starting a real listener.
func TestHandlerUnit_Health(t *testing.T) {
	w := httptest.NewRecorder()
	r := httptest.NewRequest(http.MethodGet, "/api/health", nil)
	// Access the unexported handler via the exported Server for coverage.
	srv := api.NewServer("127.0.0.1:0")
	if err := srv.Start(); err != nil {
		t.Fatal(err)
	}
	defer srv.Shutdown(5 * time.Second) //nolint:errcheck

	resp, err := http.Get(fmt.Sprintf("http://%s/api/health", srv.Addr()))
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()

	_ = w
	_ = r
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("want 200, got %d", resp.StatusCode)
	}
}