/* A package that provides advanced logging facilities. */
package monolog

import (
    "fmt"
    "os"
    "path/filepath"
    "runtime"
    "strings"
    "time"
    "unicode"
)

type Logger interface {
    Log(level string, file string, line int, format string, args ...interface{})
    Close()
}

func GetCallerName(depth int) {
    pc := make([]uintptr, depth+1)
    runtime.Callers(depth, pc)
    for i, v := range pc {
        fun := runtime.FuncForPC(v)
        if fun != nil {
            fmt.Printf("GetCallerName %d %s\n", i, fun.Name())
        } else {
            fmt.Printf("GetCallerName %d nil\n", i)
        }
    }
}

func (me *FileLogger) WriteLog(depth int, level string, format string, args ...interface{}) {
    _, file, line, ok := runtime.Caller(depth)

    if !ok {
        file = "unknown"
        line = 0
    }

    me.Log(level, file, line, format, args...)
}

func (me *FileLogger) NamedLog(name string, format string, args ...interface{}) {
    me.WriteLog(2, name, format, args...)
}

func (me *FileLogger) Info(format string, args ...interface{}) {
    me.WriteLog(2, "INFO", format, args...)
}

func (me *FileLogger) Warning(format string, args ...interface{}) {
    me.WriteLog(2, "WARNING", format, args...)
}

func (me *FileLogger) Error(format string, args ...interface{}) {
    me.WriteLog(2, "ERROR", format, args...)
}

func (me *FileLogger) Fatal(format string, args ...interface{}) {
    me.WriteLog(2, "FATAL", format, args...)
}

func (me *FileLogger) Debug(format string, args ...interface{}) {
    me.WriteLog(2, "DEBUG", format, args...)
}

type FileLogger struct {
    filename string
    file     *os.File
}

func (me *FileLogger) Close() {
    if me.file != nil {
        me.file.Close()
    }
    me.file = nil
}

func (me *FileLogger) Log(level string, file string, line int, format string, args ...interface{}) {
    fileshort := filepath.Base(file)
    now := time.Now().Format(time.RFC3339)
    fmt.Fprintf(me.file, "%s: %s: %s: %d: ", now, level, fileshort, line)
    if args != nil && len(args) > 0 {
        fmt.Fprintf(me.file, format, args...)
    } else {
        fmt.Fprint(me.file, format)
    }
    fmt.Fprint(me.file, "\n")
}

func NewFileLogger(filename string) (logger Logger, err error) {
    file, err := os.OpenFile(filename, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0660)

    if err != nil {
        return nil, err
    }

    return &FileLogger{filename, file}, nil
}

func NewStderrLogger() (logger Logger, err error) {
    return &FileLogger{"/dev/stderr", os.Stderr}, nil
}

func NewStdoutLogger() (logger Logger, err error) {
    return &FileLogger{"/dev/stderr", os.Stdout}, nil
}

type Logbook struct {
    loggers []Logger
    levels  map[string]bool
}

func NewLog() *Logbook {
    loggers := make([]Logger, 32)
    levels := make(map[string]bool)
    return &Logbook{loggers, levels}
}

func (me *Logbook) AddLogger(logger Logger) {
    me.loggers = append(me.loggers, logger)
}

func (me *Logbook) EnableLevel(level string) {
    me.levels[level] = true
}

func (me *Logbook) DisableLevel(level string) {
    me.levels[level] = false
}

func (me * Logbook) GetLevels() map[string] bool {
    return me.levels
}

func enableDisableSplitter(c rune) bool {
    ok := (!unicode.IsLetter(c))
    ok = ok && (!unicode.IsNumber(c))
    ok = ok && (c != '_')
    return ok
}

func (me *Logbook) EnableLevels(list string) {
    to_enable := strings.FieldsFunc(list, enableDisableSplitter)
    for _, level := range to_enable {
        me.EnableLevel(level)
    }
}

func (me *Logbook) DisableLevels(list string) {
    to_disable := strings.FieldsFunc(list, enableDisableSplitter)
    for _, level := range to_disable {
        me.DisableLevel(level)
    }
}

func (me *Logbook) LogVa(name string, file string, line int, format string, args ...interface{}) {
    enabled, ok := me.levels[name]

    if (!ok) || (!enabled) {
        return
    }

    for _, logger := range me.loggers {
        if logger != nil {
            logger.Log(name, file, line, format, args...)
        }
    }
}

func (me *Logbook) Close() {
    for index, logger := range me.loggers {
        if logger != nil {
            logger.Close()
            me.loggers[index] = nil
        }
    }
}

func (lb *Logbook) EnabledLevels() []string {
    var res []string
    for name, ll := range lb.levels {
        if ll {
            res = append(res, name)
        }
    }
    return res
}

var DefaultLog *Logbook

func init() {
    DefaultLog = NewLog()
    // runtime.SetFinalizer(DefaultLog, DefaultLog.Close)
}

func EnableLevel(level string) {
    DefaultLog.EnableLevel(level)
}

func DisableLevel(level string) {
    DefaultLog.DisableLevel(level)
}

func EnableLevels(list string) {
    DefaultLog.EnableLevels(list)
}

func DisableLevels(list string) {
    DefaultLog.DisableLevels(list)
}

func GetLevels() map[string] bool {
    return DefaultLog.GetLevels();
}

func AddLogger(logger Logger, err error) {
    if err == nil {
        DefaultLog.AddLogger(logger)
    }
}

func Setup(name string, stderr bool, stdout bool) {
    if name != "" {
        AddLogger(NewFileLogger(name))
    }

    if stderr {
        AddLogger(NewStderrLogger())
    }

    if stdout {
        AddLogger(NewStdoutLogger())
    }

    EnableLevel("INFO")
    EnableLevel("WARNING")
    EnableLevel("ERROR")
    EnableLevel("FATAL")
}

func Close() {
    DefaultLog.Close()
}

func WriteLog(depth int, name string, format string, args ...interface{}) {
    _, file, line, ok := runtime.Caller(depth)
    if !ok {
        file = "unknown"
        line = 0
    }
    DefaultLog.LogVa(name, file, line, format, args...)
}

func Log(name string, format string, args ...interface{}) {
    WriteLog(2, name, format, args)
}

func Printf(format string, args ...interface{}) {
    WriteLog(2, "INFO", format, args...)
}

func Info(format string, args ...interface{}) {
    WriteLog(2, "INFO", format, args...)
}

func Warning(format string, args ...interface{}) {
    WriteLog(2, "WARNING", format, args...)
}

func Error(format string, args ...interface{}) {
    WriteLog(2, "ERROR", format, args...)
}

func Fatal(format string, args ...interface{}) {
    WriteLog(2, "FATAL", format, args...)
}

func Debug(format string, args ...interface{}) {
    WriteLog(2, "DEBUG", format, args...)
}

func エラ(err error) {
    WriteLog(2, "ERROR", "%s", err.Error())
}

func WriteError(err error) {
    WriteLog(2, "ERROR", "%s", err.Error())
}