package config

import (
	"log/slog"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestNewLogger_Invalid(t *testing.T) {
	if _, _, err := NewLogger(LoggingConfig{Format: "xml"}); err == nil {
		t.Error("expected error for format xml")
	}
	if _, _, err := NewLogger(LoggingConfig{Level: "loud"}); err == nil {
		t.Error("expected error for level loud")
	}
}

func TestNewLogger_Levels(t *testing.T) {
	for _, tt := range []struct {
		in   string
		want slog.Level
	}{{"", slog.LevelInfo}, {"debug", slog.LevelDebug}, {"INFO", slog.LevelInfo}, {"warn", slog.LevelWarn}, {"warning", slog.LevelWarn}, {"error", slog.LevelError}} {
		got, err := parseLogLevel(tt.in)
		if err != nil || got != tt.want {
			t.Errorf("parseLogLevel(%q) = %v, %v; want %v", tt.in, got, err, tt.want)
		}
	}
}

// Rotation: after the file is renamed away, Reopen must create a fresh file at
// the configured path and subsequent writes must land there.
func TestLogWriter_Reopen(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "app.log")
	w, err := newLogWriter(path)
	if err != nil {
		t.Fatal(err)
	}
	defer w.Close()
	if _, err := w.Write([]byte("one\n")); err != nil {
		t.Fatal(err)
	}
	rotated := filepath.Join(dir, "app.log.0")
	if err := os.Rename(path, rotated); err != nil {
		t.Fatal(err)
	}
	if err := w.Reopen(); err != nil {
		t.Fatalf("Reopen: %v", err)
	}
	if _, err := w.Write([]byte("two\n")); err != nil {
		t.Fatal(err)
	}
	old, _ := os.ReadFile(rotated)
	fresh, _ := os.ReadFile(path)
	if strings.TrimSpace(string(old)) != "one" || strings.TrimSpace(string(fresh)) != "two" {
		t.Errorf("rotated=%q fresh=%q", old, fresh)
	}
}

func TestLogWriter_StderrReopenIsNoop(t *testing.T) {
	w, err := newLogWriter("stderr")
	if err != nil {
		t.Fatal(err)
	}
	if err := w.Reopen(); err != nil {
		t.Errorf("Reopen on stderr: %v", err)
	}
	if err := w.Close(); err != nil {
		t.Errorf("Close on stderr: %v", err)
	}
}