package otelsetup

import (
	"context"
	"errors"
	"log/slog"
	"strings"
	"sync"
	"testing"

	"github.com/99designs/gqlgen/graphql"
	"github.com/vektah/gqlparser/v2/gqlerror"
	"go.opentelemetry.io/otel/codes"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	"go.opentelemetry.io/otel/sdk/trace/tracetest"
)

type recordingHandler struct {
	mu      sync.Mutex
	records []slog.Record
}

func (h *recordingHandler) Enabled(context.Context, slog.Level) bool { return true }

func (h *recordingHandler) Handle(_ context.Context, r slog.Record) error {
	h.mu.Lock()
	defer h.mu.Unlock()
	h.records = append(h.records, r.Clone())
	return nil
}

func (h *recordingHandler) WithAttrs([]slog.Attr) slog.Handler { return h }
func (h *recordingHandler) WithGroup(string) slog.Handler      { return h }

func TestRecover(t *testing.T) {
	var _ graphql.RecoverFunc = Recover

	tests := []struct {
		name      string
		panicVal  any
		wantPanic string
	}{
		{name: "error value", panicVal: errors.New("runtime error: invalid memory address or nil pointer dereference"), wantPanic: "runtime error: invalid memory address or nil pointer dereference"},
		{name: "string value", panicVal: "boom", wantPanic: "boom"},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			h := &recordingHandler{}
			prev := slog.Default()
			slog.SetDefault(slog.New(h))
			t.Cleanup(func() { slog.SetDefault(prev) })

			sr := tracetest.NewSpanRecorder()
			tp := sdktrace.NewTracerProvider(sdktrace.WithSpanProcessor(sr))
			ctx, span := tp.Tracer("test").Start(context.Background(), "resolver")

			err := Recover(ctx, tt.panicVal)
			span.End()

			var gqlErr *gqlerror.Error
			if !errors.As(err, &gqlErr) || gqlErr.Message != "internal system error" {
				t.Fatalf("Recover() error = %v, want gqlerror \"internal system error\"", err)
			}
			if strings.Contains(err.Error(), tt.wantPanic) {
				t.Errorf("Recover() error leaks panic text: %v", err)
			}

			if len(h.records) != 1 {
				t.Fatalf("got %d log records, want exactly 1", len(h.records))
			}
			rec := h.records[0]
			if rec.Level != slog.LevelError {
				t.Errorf("log level = %v, want ERROR", rec.Level)
			}
			got := map[string]string{}
			rec.Attrs(func(a slog.Attr) bool {
				got[a.Key] = a.Value.String()
				return true
			})
			if got["panic"] != tt.wantPanic {
				t.Errorf("panic attr = %q, want %q", got["panic"], tt.wantPanic)
			}
			if !strings.Contains(got["stack"], "goroutine") {
				t.Errorf("stack attr missing stack trace: %q", got["stack"])
			}

			spans := sr.Ended()
			if len(spans) != 1 {
				t.Fatalf("got %d spans, want 1", len(spans))
			}
			s := spans[0]
			if s.Status().Code != codes.Error {
				t.Errorf("span status = %v, want Error", s.Status().Code)
			}
			var exception bool
			for _, ev := range s.Events() {
				if ev.Name != "exception" {
					continue
				}
				exception = true
				attrs := map[string]string{}
				for _, kv := range ev.Attributes {
					attrs[string(kv.Key)] = kv.Value.String()
				}
				if attrs["exception.message"] != tt.wantPanic {
					t.Errorf("exception.message = %q, want %q", attrs["exception.message"], tt.wantPanic)
				}
				if attrs["exception.stacktrace"] == "" {
					t.Error("exception event has no stacktrace")
				}
			}
			if !exception {
				t.Error("span has no exception event")
			}
		})
	}
}