package pluginutil

import (
	"context"
	"fmt"
	"reflect"
	"testing"

	"google.golang.org/grpc/metadata"
)

func TestGetMultiplexIDFromContext(t *testing.T) {
	type testCase struct {
		ctx          context.Context
		expectedResp string
		expectedErr  error
	}

	tests := map[string]testCase{
		"missing plugin multiplexing metadata": {
			ctx:          context.Background(),
			expectedResp: "",
			expectedErr:  fmt.Errorf("missing plugin multiplexing metadata"),
		},
		"unexpected number of IDs in metadata": {
			ctx:          idCtx(t, "12345", "67891"),
			expectedResp: "",
			expectedErr:  fmt.Errorf("unexpected number of IDs in metadata: (2)"),
		},
		"empty multiplex ID in metadata": {
			ctx:          idCtx(t, ""),
			expectedResp: "",
			expectedErr:  fmt.Errorf("empty multiplex ID in metadata"),
		},
		"happy path, id is returned from metadata": {
			ctx:          idCtx(t, "12345"),
			expectedResp: "12345",
			expectedErr:  nil,
		},
	}

	for name, test := range tests {
		t.Run(name, func(t *testing.T) {
			resp, err := GetMultiplexIDFromContext(test.ctx)

			if test.expectedErr != nil && test.expectedErr.Error() != "" && err == nil {
				t.Fatalf("err expected, got nil")
			} else if !reflect.DeepEqual(err, test.expectedErr) {
				t.Fatalf("Actual error: %#v\nExpected error: %#v", err, test.expectedErr)
			}

			if test.expectedErr != nil && test.expectedErr.Error() == "" && err != nil {
				t.Fatalf("no error expected, got: %s", err)
			}

			if !reflect.DeepEqual(resp, test.expectedResp) {
				t.Fatalf("Actual response: %#v\nExpected response: %#v", resp, test.expectedResp)
			}
		})
	}
}

// idCtx is a test helper that will return a context with the IDs set in its
// metadata
func idCtx(t *testing.T, ids ...string) context.Context {
	// Context doesn't need to timeout since this is just passed through
	ctx := context.Background()
	md := metadata.MD{}
	for _, id := range ids {
		md.Append(MultiplexingCtxKey, id)
	}
	return metadata.NewIncomingContext(ctx, md)
}