package pier_test

import (
	"bytes"
	"context"
	"io"
	"net/http"
	"strings"
	"testing"
	"time"

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

// TestEndpointGuards (T-19.7-18, T-19.7-19, Pitfall 10): the endpoint's own
// outer layers. A browser Origin other than the allowed ones is 403 before
// the bearer or the body is read (no Origin and the app's own origin pass);
// a request body above the endpoint's cap is 413; and a long-lived GET
// stream re-verifies its bearer and ends once the grant no longer verifies.
func TestEndpointGuards(t *testing.T) {
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()
	verifier := newFakeVerifier(map[string]pact.MCPGrant{"oas_at_stream": grant(12, "c6", 6, "read")})
	in := startInstance(t, newApp(t, appSpec{guards: []pact.MCPGuard{&acmeGuard{}}, verifier: verifier}), acmePlugin{tools: []pact.MCPTool{echoTool()}})

	post := func(token, origin string, body io.Reader) *http.Response {
		t.Helper()
		req, err := http.NewRequestWithContext(ctx, http.MethodPost, in.url(), body)
		if err != nil {
			t.Fatal(err)
		}
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("Accept", "application/json, text/event-stream")
		req.Header.Set("Mcp-Protocol-Version", "2025-11-25")
		if token != "" {
			req.Header.Set("Authorization", "Bearer "+token)
		}
		if origin != "" {
			req.Header.Set("Origin", origin)
		}
		res, err := http.DefaultClient.Do(req)
		if err != nil {
			t.Fatal(err)
		}
		_, _ = io.Copy(io.Discard, res.Body)
		_ = res.Body.Close()
		return res
	}

	t.Run("origin check", func(t *testing.T) {
		if res := post("", "https://evil.example", strings.NewReader(initializeBody)); res.StatusCode != http.StatusForbidden {
			t.Fatalf("foreign origin without a bearer = %d, want 403 before the bearer check", res.StatusCode)
		}
		if res := post("oas_at_test", "https://evil.example", strings.NewReader(initializeBody)); res.StatusCode != http.StatusForbidden {
			t.Fatalf("foreign origin = %d", res.StatusCode)
		}
		if res := post("oas_at_test", "http://acme.test", strings.NewReader(initializeBody)); res.StatusCode != http.StatusOK {
			t.Fatalf("the app's own origin = %d", res.StatusCode)
		}
		if res := post("oas_at_test", "", strings.NewReader(initializeBody)); res.StatusCode != http.StatusOK {
			t.Fatalf("no origin = %d", res.StatusCode)
		}
	})

	t.Run("body cap", func(t *testing.T) {
		big := bytes.Repeat([]byte(" "), 5<<20)
		body := append([]byte(`{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}`), big...)
		if res := post("oas_at_test", "", bytes.NewReader(body)); res.StatusCode != http.StatusRequestEntityTooLarge {
			t.Fatalf("5 MiB body = %d, want 413", res.StatusCode)
		}
	})

	t.Run("stream re-verifies its bearer", func(t *testing.T) {
		in.pier().SetRecheck(50 * time.Millisecond)
		sid := openSession(t, ctx, in, "oas_at_stream")
		req, err := http.NewRequestWithContext(ctx, http.MethodGet, in.url(), nil)
		if err != nil {
			t.Fatal(err)
		}
		req.Header.Set("Authorization", "Bearer oas_at_stream")
		req.Header.Set("Accept", "text/event-stream")
		req.Header.Set("Mcp-Session-Id", sid)
		req.Header.Set("Mcp-Protocol-Version", "2025-11-25")
		res, err := http.DefaultClient.Do(req)
		if err != nil {
			t.Fatal(err)
		}
		defer res.Body.Close()
		if res.StatusCode != http.StatusOK {
			t.Fatalf("GET stream = %d", res.StatusCode)
		}
		ended := make(chan struct{})
		go func() {
			_, _ = io.Copy(io.Discard, res.Body)
			close(ended)
		}()
		select {
		case <-ended:
			t.Fatal("the stream ended while the grant still verified")
		case <-time.After(300 * time.Millisecond):
		}
		verifier.revoke("oas_at_stream")
		select {
		case <-ended:
		case <-time.After(5 * time.Second):
			t.Fatal("the stream outlived its revoked grant")
		}
	})
}