// os-util.go
package utils

import (
	"fmt"
	"os"
	"os/user"
	"path"
	"path/filepath"
	"strings"
)

func ExpandPath(sourcePath string) (expandedPath string, err error) {
	if strings.HasPrefix(sourcePath, "~") {
		var home, userName, remainder string

		slashPos := strings.IndexRune(sourcePath, '/')
		if slashPos > 0 {
			userName = sourcePath[1:slashPos]
			remainder = sourcePath[slashPos:]
		} else {
			userName = sourcePath[1:]
		}

		if len(userName) == 0 {
			home, err = os.UserHomeDir()
			if err != nil {
				return
			}
		} else {
			var userInfo *user.User
			userInfo, err = user.Lookup(userName)
			if err != nil {
				return
			}
			home = userInfo.HomeDir
		}
		expandedPath = os.ExpandEnv(path.Join(home, remainder))
	} else {
		expandedPath = os.ExpandEnv(sourcePath)
	}
	return
}

func ExpandPathV(sourcePath string, maps ...map[string]string) (expandedPath string, err error) {
	var normalizedPath string
	if strings.HasPrefix(sourcePath, "~") {
		var home, userName, remainder string

		slashPos := strings.IndexRune(sourcePath, '/')
		if slashPos > 0 {
			userName = sourcePath[1:slashPos]
			remainder = sourcePath[slashPos:]
		} else {
			userName = sourcePath[1:]
		}

		if len(userName) == 0 {
			home, err = os.UserHomeDir()
			if err != nil {
				return
			}
		} else {
			var userInfo *user.User
			userInfo, err = user.Lookup(userName)
			if err != nil {
				return
			}
			home = userInfo.HomeDir
		}
		normalizedPath = path.Join(home, remainder)
	} else {
		normalizedPath = sourcePath
	}

	expandedPath = os.Expand(normalizedPath, func(name string) (value string) {
		var ok bool
		for _, vars := range maps {
			if value, ok = vars[name]; ok {
				break
			}
		}
		if !ok {
			value = os.Getenv(name)
		}
		return
	})
	return
}

func ExpandRealPath(sourcePath string) (expandedRealPath string, err error) {
	var expandedPath string
	if expandedPath, err = ExpandPath(sourcePath); err == nil {
		if expandedPath, err = filepath.Abs(expandedPath); err == nil {
			expandedRealPath, err = filepath.EvalSymlinks(expandedPath)
		}
	}
	return
}

func GetProgramDirPath() (dir string, err error) {
	var exe string
	exe, err = os.Executable()
	if err == nil {
		exe, err = filepath.EvalSymlinks(exe)
		if err == nil {
			exe, err = filepath.Abs(exe)
			if err == nil {
				dir = filepath.Dir(exe)
			}
		}
	}
	return
}

func GetProgramPath() (exec string, err error) {
	var tmpExec string
	tmpExec, err = os.Executable()
	if err == nil {
		tmpExec, err = filepath.EvalSymlinks(tmpExec)
		if err == nil {
			exec, err = filepath.Abs(tmpExec)
		}
	}
	return
}

func MakeParentDir(filePath string) (dir string, err error) {
	dir = filepath.Dir(filePath)
	if !IsDirectory(dir) {
		if err1 := os.MkdirAll(dir, 0755); err1 != nil {
			err = fmt.Errorf("Can't make parent path of %#v: %v", filePath, err1)
		}
	}
	return
}

func ExpandFilePathAndMakeParent(specPath string) (expandedPath, expandedParent string, err error) {
	expandedPath, err = ExpandPath(specPath)
	if err == nil {
		expandedParent, err = MakeParentDir(expandedPath)
	}
	return
}

func ExpandFilePathAndMakeParentV(specPath string, maps ...map[string]string) (expandedPath, expandedParent string, err error) {
	expandedPath, err = ExpandPathV(specPath, maps...)
	if err == nil {
		expandedParent, err = MakeParentDir(expandedPath)
	}
	return
}

func MakeDir(dirPath string) (err error) {
	if !IsDirectory(dirPath) {
		if err1 := os.MkdirAll(dirPath, 0755); err1 != nil {
			err = fmt.Errorf("Can't make directory path %#v: %v", dirPath, err1)
		}
	}
	return
}

func ExpandDirPathAndMakeParent(specPath string) (expandedPath string, err error) {
	expandedPath, err = ExpandPath(specPath)
	if err == nil {
		err = MakeDir(expandedPath)
	}
	return
}