// home: https://github.com/glycerine/vprint
// Copyright 2019 Jason E. Aten, Ph.D. All rights reserved.
// License: MIT
//
// MIT License
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package synthload

import (
	"fmt"
	"io"
	"os"
	"path"
	"runtime"
	"runtime/debug"
	"sync"
	"time"
)

const RFC3339MsecTz0 = "2006-01-02T15:04:05.000Z07:00"
const RFC3339UsecTz0 = "2006-01-02T15:04:05.000000Z07:00"

// for tons of debug output
var VerboseVerbose bool = false

// convience functions for . import
var pp = PP
var vv = VV

var panicOn = PanicOn
var _ = panicOn

func init() {
	// keeper linter happy
	_ = pp
	_ = vv
}

func PanicOn(err error) {
	if err != nil {
		panic(err)
	}
}

func PP(format string, a ...interface{}) {
	if VerboseVerbose {
		TSPrintf(format, a...)
	}
}

func VV(format string, a ...interface{}) {
	TSPrintf(format, a...)
}

func AlwaysPrintf(format string, a ...interface{}) {
	TSPrintf(format, a...)
}

var tsPrintfMut sync.Mutex

// time-stamped printf
func TSPrintf(format string, a ...interface{}) {
	tsPrintfMut.Lock()
	Printf("\n%s %s ", FileLine(3), ts())
	Printf(format+"\n", a...)
	tsPrintfMut.Unlock()
}

// get timestamp for logging purposes
func ts() string {
	return time.Now().Format(RFC3339UsecTz0)
}

// so we can multi write easily, use our own printf
var OurStdout io.Writer = os.Stdout

// Printf formats according to a format specifier and writes to standard output.
// It returns the number of bytes written and any write error encountered.
func Printf(format string, a ...interface{}) (n int, err error) {
	return fmt.Fprintf(OurStdout, format, a...)
}

func FileLine(depth int) string {
	_, fileName, fileLine, ok := runtime.Caller(depth)
	var s string
	if ok {
		s = fmt.Sprintf("%s:%d", path.Base(fileName), fileLine)
	} else {
		s = ""
	}
	return s
}

func stack() string {
	return string(debug.Stack())
}

var _ = stack

func FileExists(name string) bool {
	fi, err := os.Stat(name)
	if err != nil {
		return false
	}
	if fi.IsDir() {
		return false
	}
	return true
}

func DirExists(name string) bool {
	fi, err := os.Stat(name)
	if err != nil {
		return false
	}
	if fi.IsDir() {
		return true
	}
	return false
}

func FileSize(name string) (int64, error) {
	fi, err := os.Stat(name)
	if err != nil {
		return -1, err
	}
	return fi.Size(), nil
}

// Caller returns the name of the calling function.
func Caller(upStack int) string {
	// elide ourself and runtime.Callers
	target := upStack + 2

	pc := make([]uintptr, target+2)
	n := runtime.Callers(0, pc)

	f := runtime.Frame{Function: "unknown"}
	if n > 0 {
		frames := runtime.CallersFrames(pc[:n])
		for i := 0; i <= target; i++ {
			contender, more := frames.Next()
			if i == target {
				f = contender
			}
			if !more {
				break
			}
		}
	}
	return f.Function
}