chore: import upstream snapshot with attribution

luaplugin/api_log.go

@@ -0,0 +1,64 @@
+package luaplugin
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"time"
+
+	lua "github.com/yuin/gopher-lua"
+)
+
+// pluginLogger writes plugin log messages to ~/.config/cliamp/plugins.log.
+type pluginLogger struct {
+	mu   sync.Mutex
+	path string
+	f    *os.File
+}
+
+func newPluginLogger(path string) *pluginLogger {
+	return &pluginLogger{path: path}
+}
+
+func (l *pluginLogger) log(plugin, level, format string, args ...any) {
+	if l == nil {
+		return
+	}
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	if l.f == nil {
+		f, err := os.OpenFile(l.path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o644)
+		if err != nil {
+			return
+		}
+		l.f = f
+	}
+
+	msg := fmt.Sprintf(format, args...)
+	ts := time.Now().Format("2006-01-02 15:04:05")
+	fmt.Fprintf(l.f, "%s [%s] %s: %s\n", ts, plugin, level, msg)
+}
+
+func (l *pluginLogger) close() {
+	if l == nil || l.f == nil {
+		return
+	}
+	l.mu.Lock()
+	l.f.Close()
+	l.f = nil
+	l.mu.Unlock()
+}
+
+// registerLogAPI adds cliamp.log.{info,warn,error,debug} to the cliamp table.
+func registerLogAPI(L *lua.LState, cliamp *lua.LTable, logger *pluginLogger, pluginName string) {
+	tbl := L.NewTable()
+	for _, level := range []string{"info", "warn", "error", "debug"} {
+		L.SetField(tbl, level, L.NewFunction(func(L *lua.LState) int {
+			msg := L.CheckString(1)
+			logger.log(pluginName, level, "%s", msg)
+			return 0
+		}))
+	}
+	L.SetField(cliamp, "log", tbl)
+}