package logger

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

func TestHumanLevel(t *testing.T) {
	tests := []struct {
		level slog.Level
		want  string
	}{
		{slog.LevelDebug, "debug: "},
		{slog.LevelInfo, ""},
		{slog.LevelWarn, "warning: "},
		{slog.LevelError, "error: "},
		{slog.LevelError + 4, "error: "},
	}
	for _, tc := range tests {
		if got := humanLevel(tc.level); got != tc.want {
			t.Errorf("humanLevel(%v) = %q, want %q", tc.level, got, tc.want)
		}
	}
}

func TestHumanHandlerInfoNoPrefix(t *testing.T) {
	var buf strings.Builder
	h := newHumanHandler(&buf, slog.LevelDebug)
	slog.New(h).Info("hello world")

	if got := strings.TrimRight(buf.String(), "\n"); got != "hello world" {
		t.Errorf("got %q, want %q", got, "hello world")
	}
}

func TestHumanHandlerPrefixes(t *testing.T) {
	tests := []struct {
		fn   func(*slog.Logger, string, ...any)
		want string
	}{
		{(*slog.Logger).Warn, "warning: "},
		{(*slog.Logger).Error, "error: "},
	}
	for _, tc := range tests {
		var buf strings.Builder
		log := slog.New(newHumanHandler(&buf, slog.LevelDebug))
		tc.fn(log, "msg")
		if !strings.HasPrefix(buf.String(), tc.want) {
			t.Errorf("got %q, want prefix %q", buf.String(), tc.want)
		}
	}
}

func TestHumanHandlerAttrs(t *testing.T) {
	var buf strings.Builder
	slog.New(newHumanHandler(&buf, slog.LevelDebug)).Info("started", "port", 8080)

	want := "started port=8080\n"
	if got := buf.String(); got != want {
		t.Errorf("got %q, want %q", got, want)
	}
}

func TestHumanHandlerStringQuoting(t *testing.T) {
	var buf strings.Builder
	slog.New(newHumanHandler(&buf, slog.LevelDebug)).Warn("check", "msg", "Hello, Gopher!")

	if !strings.Contains(buf.String(), `msg="Hello, Gopher!"`) {
		t.Errorf("expected quoted value in %q", buf.String())
	}
}

func TestHumanHandlerWithAttrs(t *testing.T) {
	var buf strings.Builder
	h := newHumanHandler(&buf, slog.LevelDebug).WithAttrs([]slog.Attr{slog.String("rid", "abc")})
	slog.New(h).Info("request")

	if !strings.Contains(buf.String(), "rid=abc") {
		t.Errorf("pre-set attr missing: %q", buf.String())
	}
}

func TestHumanHandlerLevelFiltering(t *testing.T) {
	var buf strings.Builder
	log := slog.New(newHumanHandler(&buf, slog.LevelWarn))
	log.Info("dropped")
	log.Warn("kept")

	if strings.Contains(buf.String(), "dropped") {
		t.Error("INFO line should have been filtered at WARN level")
	}
	if !strings.Contains(buf.String(), "kept") {
		t.Error("WARN line should appear")
	}
}

func TestMultiHandlerFanOut(t *testing.T) {
	var screen, file strings.Builder
	// screen: INFO+, file: DEBUG+
	m := multiHandler{
		newHumanHandler(&screen, slog.LevelInfo),
		slog.NewJSONHandler(&file, &slog.HandlerOptions{Level: slog.LevelDebug}),
	}
	log := slog.New(m)
	log.Debug("trace", "k", "v")
	log.Info("event", "k", "v")

	if strings.Contains(screen.String(), "trace") {
		t.Error("DEBUG should not appear on screen")
	}
	if !strings.Contains(screen.String(), "event") {
		t.Error("INFO should appear on screen")
	}
	if !strings.Contains(file.String(), "trace") {
		t.Error("DEBUG should appear in file")
	}
	if !strings.Contains(file.String(), "event") {
		t.Error("INFO should appear in file")
	}
}