// Copyright 2013 bee authors
//
// Licensed under the Apache License, Version 2.0 (the "License"): you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations
// under the License.

package main

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

// Go is a basic promise implementation: it wraps calls a function in a goroutine
// and returns a channel which will later return the function's return value.
func Go(f func() error) chan error {
	ch := make(chan error)
	go func() {
		ch <- f()
	}()
	return ch
}

// if os.env DEBUG set, debug is on
func Debugf(format string, a ...interface{}) {
	if os.Getenv("DEBUG") != "" {
		_, file, line, ok := runtime.Caller(1)
		if !ok {
			file = "<unknown>"
			line = -1
		} else {
			file = filepath.Base(file)
		}
		fmt.Fprintf(os.Stderr, fmt.Sprintf("[debug] %s:%d %s\n", file, line, format), a...)
	}
}

const (
	Gray = uint8(iota + 90)
	Red
	Green
	Yellow
	Blue
	Magenta
	//NRed      = uint8(31) // Normal
	EndColor = "\033[0m"

	TRAC = "TRAC"
	ERRO = "ERRO"
	WARN = "WARN"
	SUCC = "SUCC"
)

// ColorLog colors log and print to stdout.
// See color rules in function 'ColorLogS'.
func ColorLog(format string, a ...interface{}) {
	fmt.Print(ColorLogS(format, a...))
}

// ColorLogS colors log and return colored content.
// Log format: <level> <content [highlight][path]> [ error ].
// Level: TRAC -> blue; ERRO -> red; WARN -> Magenta; SUCC -> green; others -> default.
// Content: default; path: yellow; error -> red.
// Level has to be surrounded by "[" and "]".
// Highlights have to be surrounded by "# " and " #"(space), "#" will be deleted.
// Paths have to be surrounded by "( " and " )"(space).
// Errors have to be surrounded by "[ " and " ]"(space).
// Note: it hasn't support windows yet, contribute is welcome.
func ColorLogS(format string, a ...interface{}) string {
	log := fmt.Sprintf(format, a...)

	var clog string

	if runtime.GOOS != "windows" {
		// Level.
		i := strings.Index(log, "]")
		if log[0] == '[' && i > -1 {
			clog += "[" + getColorLevel(log[1:i]) + "]"
		}

		log = log[i+1:]

		// Error.
		log = strings.Replace(log, "[ ", fmt.Sprintf("[\033[%dm", Red), -1)
		log = strings.Replace(log, " ]", EndColor+"]", -1)

		// Path.
		log = strings.Replace(log, "( ", fmt.Sprintf("(\033[%dm", Yellow), -1)
		log = strings.Replace(log, " )", EndColor+")", -1)

		// Highlights.
		log = strings.Replace(log, "# ", fmt.Sprintf("\033[%dm", Gray), -1)
		log = strings.Replace(log, " #", EndColor, -1)

		log = clog + log

	} else {
		// Level.
		i := strings.Index(log, "]")
		if log[0] == '[' && i > -1 {
			clog += "[" + log[1:i] + "]"
		}

		log = log[i+1:]

		// Error.
		log = strings.Replace(log, "[ ", "[", -1)
		log = strings.Replace(log, " ]", "]", -1)

		// Path.
		log = strings.Replace(log, "( ", "(", -1)
		log = strings.Replace(log, " )", ")", -1)

		// Highlights.
		log = strings.Replace(log, "# ", "", -1)
		log = strings.Replace(log, " #", "", -1)

		log = clog + log
	}

	return strings.TrimPrefix(
		time.Now().Format("2006-01-02 03:04:05 "), "20") + log
}

// getColorLevel returns colored level string by given level.
func getColorLevel(level string) string {
	level = strings.ToUpper(level)
	switch level {
	case TRAC:
		return fmt.Sprintf("\033[%dm%s\033[0m", Blue, level)
	case ERRO:
		return fmt.Sprintf("\033[%dm%s\033[0m", Red, level)
	case WARN:
		return fmt.Sprintf("\033[%dm%s\033[0m", Magenta, level)
	case SUCC:
		return fmt.Sprintf("\033[%dm%s\033[0m", Green, level)
	default:
		return level
	}
	return level
}

// IsExist returns whether a file or directory exists.
func IsExist(path string) bool {
	_, err := os.Stat(path)
	return err == nil || os.IsExist(err)
}

// GetGOPATHs returns all paths in GOPATH variable.
func GetGOPATHs() []string {
	gopath := os.Getenv("GOPATH")
	var paths []string
	if runtime.GOOS == "windows" {
		gopath = strings.Replace(gopath, "\\", "/", -1)
		paths = strings.Split(gopath, ";")
	} else {
		paths = strings.Split(gopath, ":")
	}
	return paths
}