package log

import (
	"fmt"
	"io"
	"os"
	"runtime"
	"text/template"
	"time"

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

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

var PROD = true
var LEVEL = Lerror | Linfo

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

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

	err io.Writer
	out io.Writer

	err_tmpl   *template.Template
	warn_tmpl  *template.Template
	info_tmpl  *template.Template
	debug_tmpl *template.Template
}

func New() *logger {
	l := &logger{
		err:   os.Stderr,
		out:   os.Stdout,
		color: true,
	}
	l.guessColor()
	l.SetTmpl(NewLogFormater())
	return l
}

func (l *logger) guessColor() {
	if w, ok := l.out.(*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.color = c
}

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

func (l *logger) SetTmpl(tmpl *LogFormater) error {
	funcMap := template.FuncMap{
		"Time": func() string { return time.Now().Format("2006/01/02 15:04:05") },
		// "red":     func() string { return "\033[91m" },
		// "redl":    func() string { return "\033[31m" },
		// "green":   func() string { return "\033[92m" },
		// "yellow":  func() string { return "\033[93m" },
		// "blue":    func() string { return "\033[94m" },
		// "magenta": func() string { return "\033[95m" },
		// "cyan":    func() string { return "\033[96m" },
		// "white":   func() string { return "\033[97m" },
		// "reset":   func() string { return "\033[0m" },
	}
	if l.color {

	}
	err_tmpl, err := template.New("err_tmpl").Funcs(funcMap).Parse(tmpl.ErrTmplStr)
	if err != nil {
		return err
	}
	l.err_tmpl = err_tmpl
	return nil
}

func (l *logger) error(depth int, stack string, fields H, v ...interface{}) {
	msg := fmt.Sprintln(v...)
	data := Ldata{
		Fields:  fields,
		Message: msg,
		System:  l.system,
		Caller:  caller(depth),
		Color:   l.color,
		Stack:   stack,
	}
	err := l.err_tmpl.Execute(os.Stdout, data)
	if err != nil {
		panic(err)
	}

}

func (l *logger) ErrorF(fields H, v ...interface{}) {
	stak := ""
	if !PROD {
		stak = stack()
	}
	l.error(3, stak, fields, v...)
}

func (l *logger) Error(v ...interface{}) {
	stak := ""
	if !PROD {
		stak = stack()
	}
	l.error(3, stak, H{}, v...)
}

func caller(depth int) string {
	_, file, line, _ := runtime.Caller(depth)
	short := file
	for i := len(file) - 1; i > 0; i-- {
		if file[i] == '/' {
			short = file[i+1:]
			break
		}
	}
	return fmt.Sprintf("%s:%d", short, line)
}

func stack() string {
	buf := make([]byte, 1024)
	for {
		n := runtime.Stack(buf, false)
		if n < len(buf) {
			return string(buf[:n])
		}
		buf = make([]byte, 2*len(buf))
	}
}