package sizer

import (
	"errors"
	"os"
	"path/filepath"
	"sync"
)

const (
	// FileType is a const representing a file
	FileType = iota
	// DirType is a const representing a directory
	DirType = iota
	// SymLinkType is a const representing a symbolic link
	SymLinkType = iota
	// HardLinkType is a const representing a hard link
	HardLinkType = iota
	// CharDevType is a const representing a char device
	CharDevType = iota
	// NamedPipeType is a const representing a named pipe
	NamedPipeType = iota
	// SocketType is a const representing a socket, both unix and network
	SocketType = iota
)

// INode is an entry in the filesystem. It can be:
//   - a file
//   - a directory
//   - a symbolic link
//   - a hard link
//   - a char device/named pipe/socket
// It takes a Kind (as above described), a Size and a Path
type INode struct {
	Kind     int
	Size     int64
	Path     string
	Children *INodeList
}

// INodeList is a simple *INode slice with a Mutex to allow safe
// concurrent write.
type INodeList struct {
	Elements []*INode
	safe     sync.Mutex
}

type StatusReport struct {
	path string
	size int64
	err  error
}

// Append appends safely an inode to the INodeList.
func (il *INodeList) Append(node *INode) {
	il.safe.Lock()
	il.Elements = append(il.Elements, node)
	il.safe.Unlock()
}

// INodeChan is a channel global to the sizer package that is used
// to funnel the retrieved sizes and infos on the inodes.
var INodeChan chan *INode

// ErrNotIdenfiedType is the error returned when the a classifier does not
// recognize the INode type.
var ErrNotIdenfiedType = errors.New("inode not identified")

// NewINode returns a new *INode with kind, size and path
func NewINode(kind int, size int64, path string) *INode {
	var children INodeList
	abspath, _ := filepath.Abs(path)
	var newINode = INode{
		Kind:     kind,
		Size:     size,
		Path:     abspath,
		Children: &children,
	}
	return &newINode
}

// Name returns the name of the file at the INode.
func (i *INode) Name() string {
	_, name := filepath.Split(i.Path)
	return name
}

// IdentifyType classifies a file-like object in one of the FileType.
func IdentifyType(path string) (int, int64, error) {
	f, err := os.Lstat(path)
	if err != nil {
		return -1, 0, err
	}
	switch mode := f.Mode(); {
	case mode.IsDir():
		return DirType, f.Size(), nil
	case mode.IsRegular():
		return FileType, f.Size(), nil
	}
	return -1, 0, ErrNotIdenfiedType
}

func ls(path string) ([]string, error) {
	var content []string
	f, err := os.Open(path)
	if err != nil {
		return []string{}, err
	}
	files, err := f.Readdir(-1)
	if err != nil {
		return []string{}, err
	}
	for _, fi := range files {
		content = append(content, filepath.Join(path, fi.Name()))
	}
	return content, nil
}

func INodeFromPath(path string) (*INode, error) {
	kind, _, err := IdentifyType(path)
	if err != nil {
		return nil, err
	}
	i := NewINode(kind, 0, path)
	return i, nil
}

func (i *INode) size(wg *sync.WaitGroup) {
	//Console.Debugln(i.Path)
	i.Children.safe.Lock()
	defer i.Children.safe.Unlock()
	var wgIn sync.WaitGroup
	for _, child := range i.Children.Elements {
		wg.Add(1)
		go child.walk(&wgIn)
	}
	wgIn.Wait()
	for _, child := range i.Children.Elements {
		i.Size += child.Size
		wg.Done()
	}
}

func (i *INode) walk(wg *sync.WaitGroup) {
	children, err := ls(i.Path)
	if err != nil {
		Console.Println(err)
		wg.Done()
		return
	}
	for _, child := range children {
		//Console.Debugln("Parent:", i.Path, "- Child:", child)
		kind, size, err := IdentifyType(child)
		if err != nil {
			Console.Println(child, ":", err)
		}
		childINode := NewINode(kind, size, child)
		i.Children.Append(childINode)
		switch {
		case kind == DirType:
			//Console.Debugln("Size on dir:", child)
			wg.Add(1)
			childINode.size(wg)
		case kind == FileType:
			Console.Debugln("Filesize:", child, "-", size)
			childINode.Size = size
		default:
			//Console.Debugln("Unknown:", child)
			childINode.Size = 0
		}
	}
	wg.Done()
}

func (i *INode) Sizer() {
	var wg sync.WaitGroup
	wg.Add(1)
	i.walk(&wg)
	wg.Wait()
	Console.Println(i.Size)
}