refactor: change package names

internal/ui/slog_handler.go

@@ -0,0 +1,155 @@
+package ui
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log/slog"
+	"sync"
+)
+
+const (
+	ansiClear      = "\033[0m"
+	ansiBold       = "\033[1m"
+	ansiBoldYellow = "\033[1;93m"
+	ansiBoldRed    = "\033[1;31m"
+	ansiThinGray   = "\033[2;37m"
+)
+
+type Handler struct {
+	opts HandlerOptions
+	goas []groupOrAttrs
+	mu   *sync.Mutex
+	out  io.Writer
+}
+
+type HandlerOptions struct {
+	Level slog.Leveler
+}
+
+// groupOrAttrs holds either a group name or a list of [slog.Attr].
+type groupOrAttrs struct {
+	group string      // group name if non-empty
+	attrs []slog.Attr // attrs if non-empty
+}
+
+var _ slog.Handler = &Handler{}
+
+func NewHandler(out io.Writer, opts *HandlerOptions) *Handler {
+	h := &Handler{
+		out: out,
+		mu:  &sync.Mutex{},
+	}
+	if opts != nil {
+		h.opts = *opts
+	}
+	if h.opts.Level == nil {
+		h.opts.Level = slog.LevelInfo
+	}
+	return h
+}
+
+func (h *Handler) Enabled(_ context.Context, level slog.Level) bool {
+	return level >= h.opts.Level.Level()
+}
+
+func (h *Handler) Handle(_ context.Context, record slog.Record) error {
+	buf := make([]byte, 0, 512)
+
+	formattingPrefix := ""
+
+	switch record.Level {
+	case slog.LevelInfo:
+		formattingPrefix = ansiBold
+	case slog.LevelWarn:
+		// Bold + Yellow
+		formattingPrefix = ansiBoldYellow
+	case slog.LevelError:
+		// Bold + Red
+		formattingPrefix = ansiBoldRed
+	}
+
+	// Print main message in formatted text
+	buf = fmt.Appendf(buf, "%s%s%s", formattingPrefix, record.Message, ansiClear)
+
+	// Add attributes in thin gray
+	buf = fmt.Append(buf, ansiThinGray)
+
+	// Attributes from [WithGroup] and [WithAttrs] calls
+	goas := h.goas
+	if record.NumAttrs() == 0 {
+		for len(goas) > 0 && goas[len(goas)-1].group != "" {
+			goas = goas[:len(goas)-1]
+		}
+	}
+	group := ""
+	for _, goa := range goas {
+		if goa.group != "" {
+			group = goa.group
+		} else {
+			for _, a := range goa.attrs {
+				buf = h.appendAttr(buf, group, a)
+			}
+		}
+	}
+
+	record.Attrs(func(a slog.Attr) bool {
+		buf = h.appendAttr(buf, group, a)
+		return true
+	})
+
+	buf = fmt.Appendf(buf, "%s\n", ansiClear)
+
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	_, err := h.out.Write(buf)
+	return err
+}
+
+func (h *Handler) appendAttr(buf []byte, group string, a slog.Attr) []byte {
+	a.Value = a.Value.Resolve()
+	if a.Equal(slog.Attr{}) {
+		return buf
+	}
+
+	if group != "" {
+		group += "."
+	}
+
+	switch a.Value.Kind() {
+	case slog.KindString:
+		buf = fmt.Appendf(buf, " %s%s=%q", group, a.Key, a.Value)
+	case slog.KindAny:
+		if err, ok := a.Value.Any().(error); ok {
+			buf = fmt.Appendf(buf, " %s%s=%q", group, a.Key, err.Error())
+		} else {
+			buf = fmt.Appendf(buf, " %s%s=%s", group, a.Key, a.Value)
+		}
+	default:
+		buf = fmt.Appendf(buf, " %s%s=%s", group, a.Key, a.Value)
+	}
+
+	return buf
+}
+
+func (h *Handler) WithAttrs(attrs []slog.Attr) slog.Handler {
+	if len(attrs) == 0 {
+		return h
+	}
+	return h.withGroupOrAttrs(groupOrAttrs{attrs: attrs})
+}
+
+func (h *Handler) WithGroup(name string) slog.Handler {
+	if name == "" {
+		return h
+	}
+	return h.withGroupOrAttrs(groupOrAttrs{group: name})
+}
+
+func (h *Handler) withGroupOrAttrs(goa groupOrAttrs) *Handler {
+	h2 := *h
+	h2.goas = make([]groupOrAttrs, len(h.goas)+1)
+	copy(h2.goas, h.goas)
+	h2.goas[len(h2.goas)-1] = goa
+	return &h2
+}