2 files changed, 173 insertions, 0 deletions
diff --git a/log/logger.go b/log/logger.go
new file mode 100644
index 00000000..eb52d7b7
--- /dev/null
+++ b/log/logger.go
@@ -0,0 +1,113 @@
+package log
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"strings"
+)
+
+type LogLevel int
+
+const (
+	TRACE LogLevel = 5
+	DEBUG LogLevel = 10
+	INFO  LogLevel = 20
+	WARN  LogLevel = 30
+	ERROR LogLevel = 40
+)
+
+var (
+	trace    *log.Logger
+	dbg      *log.Logger
+	info     *log.Logger
+	warn     *log.Logger
+	err      *log.Logger
+	minLevel LogLevel = TRACE
+)
+
+func Init(file *os.File, level LogLevel) {
+	minLevel = level
+	flags := log.Ldate | log.Ltime | log.Lmicroseconds | log.Lshortfile
+	if file != nil {
+		trace = log.New(file, "TRACE ", flags)
+		dbg = log.New(file, "DEBUG ", flags)
+		info = log.New(file, "INFO  ", flags)
+		warn = log.New(file, "WARN  ", flags)
+		err = log.New(file, "ERROR ", flags)
+	}
+}
+
+func ParseLevel(value string) (LogLevel, error) {
+	switch strings.ToLower(value) {
+	case "trace":
+		return TRACE, nil
+	case "debug":
+		return DEBUG, nil
+	case "info":
+		return INFO, nil
+	case "warn", "warning":
+		return WARN, nil
+	case "err", "error":
+		return ERROR, nil
+	}
+	return 0, fmt.Errorf("%s: invalid log level", value)
+}
+
+func ErrorLogger() *log.Logger {
+	if err == nil {
+		return log.New(io.Discard, "", log.LstdFlags)
+	}
+	return err
+}
+
+func Tracef(message string, args ...interface{}) {
+	if trace == nil || minLevel > TRACE {
+		return
+	}
+	if len(args) > 0 {
+		message = fmt.Sprintf(message, args...)
+	}
+	trace.Output(2, message) //nolint:errcheck // we can't do anything with what we log
+}
+
+func Debugf(message string, args ...interface{}) {
+	if dbg == nil || minLevel > DEBUG {
+		return
+	}
+	if len(args) > 0 {
+		message = fmt.Sprintf(message, args...)
+	}
+	dbg.Output(2, message) //nolint:errcheck // we can't do anything with what we log
+}
+
+func Infof(message string, args ...interface{}) {
+	if info == nil || minLevel > INFO {
+		return
+	}
+	if len(args) > 0 {
+		message = fmt.Sprintf(message, args...)
+	}
+	info.Output(2, message) //nolint:errcheck // we can't do anything with what we log
+}
+
+func Warnf(message string, args ...interface{}) {
+	if warn == nil || minLevel > WARN {
+		return
+	}
+	if len(args) > 0 {
+		message = fmt.Sprintf(message, args...)
+	}
+	warn.Output(2, message) //nolint:errcheck // we can't do anything with what we log
+}
+
+func Errorf(message string, args ...interface{}) {
+	if err == nil || minLevel > ERROR {
+		return
+	}
+	if len(args) > 0 {
+		message = fmt.Sprintf(message, args...)
+	}
+	err.Output(2, message) //nolint:errcheck // we can't do anything with what we log
+}
diff --git a/log/panic-logger.go b/log/panic-logger.go
new file mode 100644
index 00000000..a1904415
--- /dev/null
+++ b/log/panic-logger.go
@@ -0,0 +1,60 @@
+package log
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"runtime/debug"
+	"strings"
+	"time"
+)
+
+var (
+	UICleanup = func() {}
+	BuildInfo string
+)
+
+// PanicHandler tries to restore the terminal. A stack trace is written to
+// aerc-crash.log and then passed on if a panic occurs.
+func PanicHandler() {
+	r := recover()
+
+	if r == nil {
+		return
+	}
+
+	UICleanup()
+
+	filename := time.Now().Format("/tmp/aerc-crash-20060102-150405.log")
+
+	panicLog, err := os.OpenFile(filename, os.O_SYNC|os.O_APPEND|os.O_CREATE|os.O_WRONLY|os.O_EXCL, 0o600)
+	if err != nil {
+		// we tried, not possible. bye
+		panic(r)
+	}
+	defer panicLog.Close()
+
+	outputs := io.MultiWriter(panicLog, os.Stderr)
+
+	// if any error happens here, we do not care.
+	fmt.Fprintln(panicLog, strings.Repeat("#", 80))
+	fmt.Fprint(panicLog, strings.Repeat(" ", 34))
+	fmt.Fprintln(panicLog, "PANIC CAUGHT!")
+	fmt.Fprint(panicLog, strings.Repeat(" ", 24))
+	fmt.Fprintln(panicLog, time.Now().Format("2006-01-02T15:04:05.000000-0700"))
+	fmt.Fprintln(panicLog, strings.Repeat("#", 80))
+	fmt.Fprintf(outputs, "%s\n", panicMessage)
+	fmt.Fprintf(outputs, "Version: %s\n", BuildInfo)
+	fmt.Fprintf(panicLog, "Error: %v\n\n", r)
+	panicLog.Write(debug.Stack()) //nolint:errcheck // we are already in a panic, so not much we can do here
+	fmt.Fprintf(os.Stderr, "\nThis error was also written to: %s\n", filename)
+	panic(r)
+}
+
+const panicMessage = `
+aerc has encountered a critical error and has terminated. Please help us fix
+this by sending this log and the steps to reproduce the crash to:
+~rjarry/aerc-devel@lists.sr.ht
+
+Thank you
+`