package logging

import (
	"bytes"
	"log/slog"
	"strings"
	"testing"
)

func TestNewWritesReadableStructuredText(t *testing.T) {
	var output bytes.Buffer
	New(&output, slog.LevelInfo).Info("server ready", "listen", ":8080")

	line := output.String()
	if strings.HasPrefix(strings.TrimSpace(line), "{") {
		t.Fatalf("expected text output, got JSON: %s", line)
	}
	for _, want := range []string{`level=INFO`, `msg="server ready"`, `listen=:8080`} {
		if !strings.Contains(line, want) {
			t.Errorf("output %q does not contain %q", line, want)
		}
	}
}

func TestBufferedLoggerRetainsStructuredEventsWithCursorPagination(t *testing.T) {
	var output bytes.Buffer
	logger, buffer := NewBuffered(&output, slog.LevelDebug, 3)
	for i := 1; i <= 5; i++ {
		logger.Info("request complete", "number", i)
	}

	first := buffer.Events(0, 2)
	if first.Dropped != 2 || len(first.Events) != 2 || !first.HasMore {
		t.Fatalf("unexpected first page: %+v", first)
	}
	if first.Events[0].Sequence != 3 || first.Events[0].Attributes["number"] != "3" {
		t.Fatalf("oldest retained event was not delivered: %+v", first.Events[0])
	}
	second := buffer.Events(first.Next, 2)
	if len(second.Events) != 1 || second.Events[0].Sequence != 5 || second.HasMore {
		t.Fatalf("unexpected second page: %+v", second)
	}
}

func TestParseLevel(t *testing.T) {
	tests := map[string]slog.Level{
		"":        slog.LevelInfo,
		"debug":   slog.LevelDebug,
		"WARNING": slog.LevelWarn,
		"error":   slog.LevelError,
		"unknown": slog.LevelInfo,
	}
	for input, want := range tests {
		if got := ParseLevel(input); got != want {
			t.Errorf("ParseLevel(%q) = %v, want %v", input, got, want)
		}
	}
}