package surf

import (
	"errors"
	"net/http"
	"net/http/httptest"
	"regexp"
	"strings"
	"testing"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/party"
)

// Unit tests for the opt-in /api-docs page (D-16, D-17) of phase 19.3.

// specPlugin supplies a fixed spec (or error) for /api-docs.
type specPlugin struct {
	id   string
	spec string
	err  error
}

func (p specPlugin) ID() string                   { return p.id }
func (p specPlugin) Requires() []string           { return nil }
func (p specPlugin) Register(*backpack.App) error { return nil }
func (p specPlugin) Boot(*backpack.App) error     { return nil }
func (p specPlugin) APIDocsSpec() ([]byte, error) { return []byte(p.spec), p.err }

const orderedSpecYAML = `openapi: 3.0.3
info:
  version: "2"
  title: Zoo API
paths:
  /zebras:
    get:
      summary: List zebras
  /aardvarks:
    post:
      summary: Add an aardvark
components: {}
`

func apiDocsApp(t *testing.T, apiDocs string) *backpack.App {
	t.Helper()
	return transportApp(t, "development", map[string]string{"http.yaml": transportBodyLimits + apiDocs})
}

func apiGet(h http.Handler, path string) *httptest.ResponseRecorder {
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, path, nil))
	return rec
}

func TestAPIDocsOffByDefault(t *testing.T) {
	for name, cfg := range map[string]string{
		"unset":          "",
		"enabled false":  "api_docs:\n  enabled: false\n  path: /docs\n",
		"only the title": "api_docs:\n  title: Docs\n",
	} {
		t.Run(name, func(t *testing.T) {
			router, err := BuildRouter(apiDocsApp(t, cfg), []party.Plugin{specPlugin{id: "acme.zoo", spec: orderedSpecYAML}})
			if err != nil {
				t.Fatal(err)
			}
			for _, ri := range router.Routes() {
				if ri.PluginID == apiDocsPluginID {
					t.Fatalf("api docs route mounted while off: %+v", ri)
				}
			}
			h, err := router.compile()
			if err != nil {
				t.Fatal(err)
			}
			for _, p := range []string{"/api-docs", "/api-docs.json", "/docs"} {
				if rec := apiGet(h, p); rec.Code != http.StatusNotFound {
					t.Fatalf("GET %s = %d while off", p, rec.Code)
				}
			}
		})
	}
	// Off needs no provider, and a broken spec is never read.
	if _, err := Assemble(apiDocsApp(t, ""), []party.Plugin{specPlugin{id: "acme.zoo", err: errors.New("boom")}}); err != nil {
		t.Fatalf("off with a failing provider: %v", err)
	}
	if _, err := Assemble(apiDocsApp(t, ""), nil); err != nil {
		t.Fatalf("off without a provider: %v", err)
	}
}

func TestAPIDocsServesPinnedPage(t *testing.T) {
	h, err := Assemble(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{specPlugin{id: "acme.zoo", spec: orderedSpecYAML}})
	if err != nil {
		t.Fatal(err)
	}
	if SwaggerUIVersion != "5.33.1" {
		t.Fatalf("SwaggerUIVersion = %q", SwaggerUIVersion)
	}
	rec := apiGet(h, "/api-docs")
	page := rec.Body.String()
	if rec.Code != http.StatusOK || rec.Header().Get("Content-Type") != "text/html; charset=utf-8" {
		t.Fatalf("GET /api-docs = %d %q", rec.Code, rec.Header().Get("Content-Type"))
	}
	// The integrity values from RESEARCH (npm tarball and jsDelivr bytes).
	for asset, sri := range map[string]string{
		"https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.33.1/swagger-ui.css":                  "sha384-Ov4/wv3j2bmct8cDc5X4ngJZohVPzEmc6uDPH8WeljUxO5vtoykvMEfbu9Vh6RaW",
		"https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.33.1/swagger-ui-bundle.js":            "sha384-ZPehFMQommnnuaZ4rpxgkgTT2DKFVp4hZC/7pLit+9Lek9T1YGSo23eHFbvNkXkw",
		"https://cdn.jsdelivr.net/npm/swagger-ui-dist@5.33.1/swagger-ui-standalone-preset.js": "sha384-My2aDM4r2Mbm3ybHcubKm9O9U8FEjvF/O5nGvE9YK5dzqOTbWEKa79RPJ1krdMaF",
	} {
		if !strings.Contains(page, `"`+asset+`" integrity="`+sri+`" crossorigin="anonymous"`) {
			t.Errorf("page lacks %s with integrity %s and crossorigin", asset, sri)
		}
	}
	if n := strings.Count(page, `integrity="sha384-`); n != 3 {
		t.Errorf("integrity attributes = %d, want 3", n)
	}
	if n := strings.Count(page, `crossorigin="anonymous"`); n != 3 {
		t.Errorf("crossorigin attributes = %d, want 3", n)
	}
	if strings.Contains(page, "swagger-ui-dist@5/") || strings.Contains(page, "@latest") {
		t.Error("page loads a floating version")
	}

	hd := rec.Header()
	if hd.Get("X-Content-Type-Options") != "nosniff" || hd.Get("Referrer-Policy") != "no-referrer" {
		t.Errorf("headers = %v", hd)
	}
	csp := hd.Get("Content-Security-Policy")
	m := regexp.MustCompile(`script-src 'nonce-([A-Za-z0-9_-]+)';`).FindStringSubmatch(csp)
	if m == nil {
		t.Fatalf("CSP %q", csp)
	}
	if strings.Contains(csp, "https:") {
		t.Errorf("CSP %q names a host source; script-src must hold only the nonce", csp)
	}
	for _, part := range []string{"object-src 'none'", "base-uri 'none'", "frame-ancestors 'none'"} {
		if !strings.Contains(csp, part) {
			t.Errorf("CSP %q lacks %s", csp, part)
		}
	}
	scripts := regexp.MustCompile(`<script nonce="([^"]+)">`).FindAllStringSubmatch(page, -1)
	if len(scripts) != 1 || scripts[0][1] != m[1] {
		t.Fatalf("inline script nonces %v, CSP nonce %q", scripts, m[1])
	}
	// Every script tag, the two pinned assets included, carries the nonce.
	tags := regexp.MustCompile(`<script[^>]*>`).FindAllString(page, -1)
	if len(tags) != 3 {
		t.Fatalf("script tags = %q, want 3", tags)
	}
	for _, tag := range tags {
		if !strings.Contains(tag, `nonce="`+m[1]+`"`) {
			t.Errorf("script tag %q lacks the CSP nonce", tag)
		}
	}
	if !strings.Contains(page, `url: "/api-docs.json"`) || !strings.Contains(page, "validatorUrl: null") {
		t.Error("page does not load the local spec with the validator off")
	}

	// A fresh nonce per request.
	rec2 := apiGet(h, "/api-docs")
	if rec2.Header().Get("Content-Security-Policy") == csp {
		t.Error("nonce reused across requests")
	}

	spec := apiGet(h, "/api-docs.json")
	if spec.Code != http.StatusOK || spec.Header().Get("Content-Type") != "application/json" || spec.Header().Get("X-Content-Type-Options") != "nosniff" {
		t.Fatalf("GET /api-docs.json = %d %v", spec.Code, spec.Header())
	}
	// Both routes are public: a request without credentials gets them.
	router, err := BuildRouter(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{specPlugin{id: "acme.zoo", spec: orderedSpecYAML}})
	if err != nil {
		t.Fatal(err)
	}
	n := 0
	for _, ri := range router.Routes() {
		if ri.PluginID == apiDocsPluginID {
			n++
			if ri.Method != http.MethodGet || len(ri.Middleware) != 0 {
				t.Errorf("api docs route %+v", ri)
			}
		}
	}
	if n != 2 {
		t.Fatalf("api docs routes = %d, want 2", n)
	}
}

func TestAPIDocsSpecJSONOrder(t *testing.T) {
	want := `{"openapi":"3.0.3","info":{"version":"2","title":"Zoo API"},"paths":{"/zebras":{"get":{"summary":"List zebras"}},"/aardvarks":{"post":{"summary":"Add an aardvark"}}},"components":{}}`
	got, err := apiDocsJSON([]byte(orderedSpecYAML))
	if err != nil {
		t.Fatal(err)
	}
	if string(got) != want {
		t.Fatalf("apiDocsJSON = %s\nwant %s", got, want)
	}
	h, err := Assemble(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{specPlugin{id: "acme.zoo", spec: orderedSpecYAML}})
	if err != nil {
		t.Fatal(err)
	}
	if rec := apiGet(h, "/api-docs.json"); rec.Body.String() != want {
		t.Fatalf("served %s", rec.Body.String())
	}
}

func TestAPIDocsJSONSpecInput(t *testing.T) {
	got, err := apiDocsJSON([]byte("\n  {\n  \"openapi\": \"3.1.0\",\n  \"paths\": {\"/b\": {}, \"/a\": {}},\n  \"info\": {\"title\": \"T\"}\n}\n"))
	if err != nil {
		t.Fatal(err)
	}
	if string(got) != `{"openapi":"3.1.0","paths":{"/b":{},"/a":{}},"info":{"title":"T"}}` {
		t.Fatalf("JSON input = %s", got)
	}
	for name, raw := range map[string]string{
		"empty":           "  \n",
		"broken json":     `{"openapi": "3.0.3",`,
		"broken yaml":     "openapi: [3.0\n  : x",
		"not an object":   "- a\n- b\n",
		"scalar document": "just text",
	} {
		if out, err := apiDocsJSON([]byte(raw)); err == nil {
			t.Errorf("%s: converted to %s, want an error", name, out)
		}
	}

	// A spec that does not convert, or a provider error, fails boot naming the plugin.
	for name, p := range map[string]specPlugin{
		"bad spec":       {id: "acme.zoo", spec: `{"broken"`},
		"provider error": {id: "acme.zoo", err: errors.New("embedded file missing")},
	} {
		_, err := BuildRouter(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{p})
		if err == nil || !strings.Contains(err.Error(), `"acme.zoo"`) {
			t.Errorf("%s: error = %v", name, err)
		}
	}
}

func TestAPIDocsProviderCount(t *testing.T) {
	plain := routesPluginFunc{id: "acme.plain", routes: func(pact.Router) {}}
	_, err := BuildRouter(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{plain})
	if err == nil || !strings.Contains(err.Error(), "no plugin implements surf.APIDocsProvider") {
		t.Fatalf("zero providers: %v", err)
	}
	_, err = BuildRouter(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{
		specPlugin{id: "acme.zoo", spec: orderedSpecYAML}, plain, specPlugin{id: "acme.blog", spec: orderedSpecYAML},
	})
	if err == nil || !strings.Contains(err.Error(), "acme.blog, acme.zoo") || !strings.Contains(err.Error(), "exactly one") {
		t.Fatalf("two providers: %v", err)
	}
}

func TestAPIDocsPathValidation(t *testing.T) {
	zoo := specPlugin{id: "acme.zoo", spec: orderedSpecYAML}
	h, err := Assemble(apiDocsApp(t, "api_docs:\n  enabled: true\n  path: /docs/api/\n"), []party.Plugin{zoo})
	if err != nil {
		t.Fatal(err)
	}
	if rec := apiGet(h, "/docs/api"); rec.Code != http.StatusOK || !strings.Contains(rec.Body.String(), `url: "/docs/api.json"`) {
		t.Fatalf("GET /docs/api = %d", rec.Code)
	}
	if rec := apiGet(h, "/docs/api.json"); rec.Code != http.StatusOK {
		t.Fatalf("GET /docs/api.json = %d", rec.Code)
	}
	if rec := apiGet(h, "/api-docs"); rec.Code != http.StatusNotFound {
		t.Fatalf("default path still served: %d", rec.Code)
	}

	for _, bad := range []string{"docs", "https://example.com/docs", "/docs?x=1", "/docs/{rest}", "/docs/../admin", "/docs//api", "/do cs", `/docs\x`} {
		_, err := BuildRouter(apiDocsApp(t, "api_docs:\n  enabled: true\n  path: '"+bad+"'\n"), []party.Plugin{zoo})
		if err == nil || !strings.Contains(err.Error(), "http.api_docs.path") {
			t.Errorf("path %q: error = %v", bad, err)
		}
	}

	// A plugin route on the docs path collides.
	clash := routesPluginFunc{id: "acme.clash", routes: func(r pact.Router) {
		r.Get("/api-docs.json", okHandler)
	}}
	_, err = BuildRouter(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{zoo, clash})
	if err == nil || !strings.Contains(err.Error(), "/api-docs.json") || !strings.Contains(err.Error(), "acme.clash") {
		t.Fatalf("collision error = %v", err)
	}
}

func TestAPIDocsTitleEscaped(t *testing.T) {
	h, err := Assemble(apiDocsApp(t, "api_docs:\n  enabled: true\n  title: '</title><script>alert(1)</script> & co'\n"), []party.Plugin{specPlugin{id: "acme.zoo", spec: orderedSpecYAML}})
	if err != nil {
		t.Fatal(err)
	}
	page := apiGet(h, "/api-docs").Body.String()
	if strings.Contains(page, "<script>alert(1)</script>") || strings.Count(page, "</title>") != 1 {
		t.Fatalf("title not escaped:\n%s", page)
	}
	if !strings.Contains(page, "<title>&lt;/title&gt;&lt;script&gt;alert(1)&lt;/script&gt; &amp; co</title>") {
		t.Fatalf("escaped title missing:\n%s", page)
	}

	// The default title.
	h, err = Assemble(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{specPlugin{id: "acme.zoo", spec: orderedSpecYAML}})
	if err != nil {
		t.Fatal(err)
	}
	if page := apiGet(h, "/api-docs").Body.String(); !strings.Contains(page, "<title>API documentation</title>") {
		t.Fatal("default title missing")
	}
}

// cspDirectives splits a Content-Security-Policy value into its directives.
func cspDirectives(csp string) map[string][]string {
	out := map[string][]string{}
	for _, part := range strings.Split(csp, ";") {
		fields := strings.Fields(part)
		if len(fields) == 0 {
			continue
		}
		out[fields[0]] = fields[1:]
	}
	return out
}

func TestAPIDocsCSPNoHostSource(t *testing.T) {
	h, err := Assemble(apiDocsApp(t, "api_docs:\n  enabled: true\n"), []party.Plugin{specPlugin{id: "acme.zoo", spec: orderedSpecYAML}})
	if err != nil {
		t.Fatal(err)
	}
	nonces := map[string]bool{}
	for range 2 {
		rec := apiGet(h, "/api-docs")
		if rec.Code != http.StatusOK {
			t.Fatalf("GET /api-docs = %d", rec.Code)
		}
		dirs := cspDirectives(rec.Header().Get("Content-Security-Policy"))
		script := dirs["script-src"]
		if len(script) != 1 || !strings.HasPrefix(script[0], "'nonce-") || !strings.HasSuffix(script[0], "'") {
			t.Fatalf("script-src = %q, want exactly one nonce source", script)
		}
		nonce := strings.TrimSuffix(strings.TrimPrefix(script[0], "'nonce-"), "'")
		if nonce == "" {
			t.Fatal("empty nonce")
		}
		for _, d := range []string{"object-src", "base-uri", "frame-ancestors"} {
			if got := dirs[d]; len(got) != 1 || got[0] != "'none'" {
				t.Errorf("%s = %q, want 'none'", d, got)
			}
		}
		page := rec.Body.String()
		tags := regexp.MustCompile(`<script[^>]*>`).FindAllString(page, -1)
		if len(tags) != 3 {
			t.Fatalf("script tags = %q, want 3", tags)
		}
		for _, tag := range tags {
			if !strings.Contains(tag, ` nonce="`+nonce+`"`) {
				t.Errorf("script tag %q lacks nonce %q", tag, nonce)
			}
		}
		for _, sri := range []string{
			"sha384-Ov4/wv3j2bmct8cDc5X4ngJZohVPzEmc6uDPH8WeljUxO5vtoykvMEfbu9Vh6RaW",
			"sha384-ZPehFMQommnnuaZ4rpxgkgTT2DKFVp4hZC/7pLit+9Lek9T1YGSo23eHFbvNkXkw",
			"sha384-My2aDM4r2Mbm3ybHcubKm9O9U8FEjvF/O5nGvE9YK5dzqOTbWEKa79RPJ1krdMaF",
		} {
			if !strings.Contains(page, `integrity="`+sri+`"`) {
				t.Errorf("page lacks integrity %s", sri)
			}
		}
		nonces[nonce] = true
	}
	if len(nonces) != 2 {
		t.Fatal("two requests got the same nonce")
	}
}