package klog

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"sync"
	"text/template"
	"time"

	"github.com/mattn/go-isatty"
)

const (
	Lerror = 1 << iota
	Ldebug
	Lwarn
	Linfo
)

type tout int

const (
	terror tout = iota
	tdebug
	tinfo
	twarn
)

var lock sync.Mutex

var PROD = true
var LEVEL = Lerror | Linfo

const (
	DEFAULT_ERR = `{{Time}} [{{"ERROR"|red}}]` +
		`{{if .System}}({{.System|cyan}}){{end}} ` +
		`{{.Caller}} {{.Message}}` +
		`{{if .Fields}} {{.Fields|json|green}}{{end}}{{"\n"}}` +
		`{{if .Stack}}{{.Stack|redl}}{{end}}`
	DEFAULT_DEBUG = `{{Time}} [{{"DEBUG"|magenta}}]` +
		`{{if .System}}({{.System|cyan}}){{end}} ` +
		`{{.Caller}} {{.Message}}` +
		`{{if .Fields}} {{.Fields|json|green}}{{end}}{{"\n"}}` +
		`{{if .Stack}}{{.Stack|redl}}{{end}}`
	DEFAULT_WARN = `{{Time}} [{{"WARN"|yellow}} ]` +
		`{{if .System}}({{.System|cyan}}){{end}} ` +
		`{{.Message}}` +
		`{{if .Fields}} {{.Fields|json|green}}{{end}}{{"\n"}}`
	DEFAULT_INFO = `{{Time}} [{{"INFO"|blue}} ]` +
		`{{if .System}}({{.System|cyan}}){{end}} ` +
		`{{.Message}}` +
		`{{if .Fields}} {{.Fields|json|green}}{{end}}{{"\n"}}`
)

type LogFormater struct {
	ErrTmplStr   string
	WarnTmplStr  string
	InfoTmplStr  string
	DebugTmplStr string
}

type H map[string]interface{}

type Ldata struct {
	Message string
	System  string

	// Caller only evaluates in DEBUG, and ERROR calls
	Caller string

	// Stack only eval when !PROD and {DEBUG, ERROR}
	Stack  string
	Fields H

	Color bool
}

type Logger struct {
	system string
	color  bool

	explicit bool

	err io.Writer
	out io.Writer

	formatter  *LogFormater
	funcMap    template.FuncMap
	err_tmpl   *template.Template
	debug_tmpl *template.Template
	warn_tmpl  *template.Template
	info_tmpl  *template.Template
	subs       []*Logger
}

func New(name string) *Logger {
	l := &Logger{
		system:    name,
		err:       os.Stderr,
		out:       os.Stdout,
		color:     true,
		formatter: NewLogFormater(),
	}
	l.Reload()
	return l
}

func (l *Logger) Sub(sys string) *Logger {
	ret := &Logger{
		system:    sys,
		err:       l.err,
		out:       l.out,
		color:     l.color,
		formatter: l.formatter,

		err_tmpl:   l.err_tmpl,
		debug_tmpl: l.debug_tmpl,
		warn_tmpl:  l.warn_tmpl,
		info_tmpl:  l.info_tmpl,
	}
	if l.subs == nil {
		l.subs = make([]*Logger, 0)
	}
	l.subs = append(l.subs, ret)
	return ret
}

func (l *Logger) guessColor() {
	l.color = true
	if w, ok := l.out.(*os.File); !ok || os.Getenv("TERM") == "dumb" ||
		(!isatty.IsTerminal(w.Fd()) && !isatty.IsCygwinTerminal(w.Fd())) {
		l.color = false
	}
	if w, ok := l.err.(*os.File); !ok || os.Getenv("TERM") == "dumb" ||
		(!isatty.IsTerminal(w.Fd()) && !isatty.IsCygwinTerminal(w.Fd())) {
		l.color = false
	}
}
func (l *Logger) SetColor(c bool) {
	l.explicit = true
	l.color = c
}

func (l *Logger) SetColorAll(c bool) {
	for _, v := range getAllOffsprings(l) {
		v.SetColor(c)
	}
}

func (l *Logger) SetErrOutput(err io.Writer) {
	l.err = err
}

func (l *Logger) SetErrOutputAll(err io.Writer) {
	for _, v := range getAllOffsprings(l) {
		v.err = err
	}
}

func (l *Logger) SetOutput(out io.Writer) {
	l.out = out
}

func (l *Logger) SetOutputAll(out io.Writer) {
	for _, v := range getAllOffsprings(l) {
		v.out = out
	}
}

func (l *Logger) Reload() error {
	if !l.explicit {
		l.guessColor()
	}
	return l.ParseTmpl()
}

func (l *Logger) ReloadAll() error {
	for _, v := range getAllOffsprings(l) {
		if err := v.Reload(); err != nil {
			return err
		}
	}
	return nil
}

func NewLogFormater() *LogFormater {
	return &LogFormater{
		ErrTmplStr:   DEFAULT_ERR,
		WarnTmplStr:  DEFAULT_WARN,
		InfoTmplStr:  DEFAULT_INFO,
		DebugTmplStr: DEFAULT_DEBUG,
	}
}

func (l *Logger) DefaultFuncMap() template.FuncMap {
	funcMap := template.FuncMap{
		"Time": func() string { return time.Now().Format("2006/01/02 15:04:05") },
		"json": func(i interface{}) (string, error) { r, err := json.Marshal(i); return string(r), err },
	}
	return funcMap
}

func (l *Logger) ParseTmpl() error {
	if l.funcMap == nil {
		l.funcMap = l.DefaultFuncMap()
	}
	funcMap := copyFuncMap(l.funcMap)
	l.setColorMap(funcMap)

	err_tmpl, err := template.New("err_tmpl").Funcs(funcMap).Parse(l.formatter.ErrTmplStr)
	if err != nil {
		return err
	}
	l.err_tmpl = err_tmpl
	warn_tmpl, err := template.New("warn_tmpl").Funcs(funcMap).Parse(l.formatter.WarnTmplStr)
	if err != nil {
		return err
	}
	l.warn_tmpl = warn_tmpl
	info_tmpl, err := template.New("info_tmpl").Funcs(funcMap).Parse(l.formatter.InfoTmplStr)
	if err != nil {
		return err
	}
	l.info_tmpl = info_tmpl
	debug_tmpl, err := template.New("debug_tmpl").Funcs(funcMap).Parse(l.formatter.DebugTmplStr)
	if err != nil {
		return err
	}
	l.debug_tmpl = debug_tmpl
	return nil
}

func (l *Logger) SetTmpl(formatter *LogFormater, funcMap template.FuncMap) {
	l.formatter = formatter
	if funcMap != nil {
		l.funcMap = funcMap
	}
}

func (l *Logger) output(t tout, depth int, stack string, fields H, v ...interface{}) {
	msg := fmt.Sprint(v...)
	data := Ldata{
		Fields:  fields,
		Message: msg,
		System:  l.system,
		Caller:  caller(depth),
		Color:   l.color,
		Stack:   stack,
	}
	lock.Lock()
	defer lock.Unlock()
	var err error
	switch t {
	case terror:
		if LEVEL&Lerror == 0 {
			return
		}
		err = l.err_tmpl.Execute(l.err, data)
	case tdebug:
		if LEVEL&Ldebug == 0 {
			return
		}
		err = l.debug_tmpl.Execute(l.err, data)
	case twarn:
		if LEVEL&Lwarn == 0 {
			return
		}
		err = l.warn_tmpl.Execute(l.out, data)
	case tinfo:
		if LEVEL&Linfo == 0 {
			return
		}
		err = l.info_tmpl.Execute(l.out, data)
	}
	if err != nil {
		fmt.Fprintln(l.err, "[FATAL] Logger error:", err)
		panic(err)
	}
}

func (l *Logger) ErrorF(fields H, v ...interface{}) {
	if PROD {
		l.output(terror, 3, "", fields, v...)
	} else {
		l.output(terror, 3, stack(), fields, v...)
	}
}

func (l *Logger) Error(v ...interface{}) {
	if PROD {
		l.output(terror, 3, "", H{}, v...)
	} else {
		l.output(terror, 3, stack(), H{}, v...)
	}
}

func (l *Logger) DebugF(fields H, v ...interface{}) {
	if PROD {
		l.output(tdebug, 3, "", fields, v...)
	} else {
		l.output(tdebug, 3, stack(), fields, v...)
	}
}

func (l *Logger) Debug(v ...interface{}) {
	if PROD {
		l.output(tdebug, 3, "", H{}, v...)
	} else {
		l.output(tdebug, 3, stack(), H{}, v...)
	}
}

func (l *Logger) WarnF(fields H, v ...interface{}) {
	l.output(twarn, 3, "", fields, v...)
}

func (l *Logger) Warn(v ...interface{}) {
	l.output(twarn, 3, "", H{}, v...)
}

func (l *Logger) InfoF(fields H, v ...interface{}) {
	l.output(tinfo, 3, "", fields, v...)
}

func (l *Logger) Info(v ...interface{}) {
	l.output(tinfo, 3, "", H{}, v...)
}