return if global.window

ion = require '../'
fs = require 'fs'
np = require 'path'
util = require './utility'

# watches a directory recursively for file changes
# will call the listener once for each matching file
# immediately and then whenever
# files are changed, deleted or created
exports.watchDirectory = (dirname, options, listener) ->
    if not listener?
        listener = options
        options = {}
    options.persistent ?= true
    options.interval ?= 100
    options.recursive ?= true
    # change message for initial pass. Use false for no initial pass.
    options.initial ?= 'initial'
    options.exclude ?= util.defaultFileExclude

    filter = (name) ->
        if util.isMatch name, options.exclude, false
            false
        else
            util.isMatch name, options.include, true

    watchedFiles = {}   # filename => bound listener

    notifyListener = (filename, curr, prev, change, async=false) ->
        if filter filename
            if async
                ion.setImmediate -> listener filename, curr, prev, change
            else
                listener filename, curr, prev, change

    fsListener = (filename, depth, curr, prev) ->
        change =
            if curr.nlink is 0
                'deleted'
            else if prev.nlink is 0
                'created'
            else
                'modified'
        notifyListener filename, curr, prev, change
        # we call watchFile again in case children were added
        if change isnt 'deleted'
            watchFile filename, depth, curr
        else
            unwatchFile filename

    unwatchFile = (filename) ->
        fs.unwatchFile filename, watchedFiles[filename]
        delete watchedFiles[filename]
        allWatchers[filename]--

    watchFile = (filename, depth=0, stats) ->
        if fs.existsSync filename
            stats ?= fs.statSync filename
            if stats.nlink > 0
                if stats.isDirectory()
                    # also watch all children
                    # exclude directories in exclude list
                    if not util.isMatch filename, options.exclude, false
                        if depth is 0 or options.recursive
                            for child in fs.readdirSync filename
                                child = np.join filename, child
                                watchFile child, depth + 1

                if not watchedFiles[filename]?
                    allWatchers[filename] ?= 0
                    allWatchers[filename]++

                    boundListener = fsListener.bind @, filename, depth
                    watchedFiles[filename] = boundListener
                    fs.watchFile filename, options, boundListener
                    if initial
                        notifyListener filename, stats, stats, initial, true
        return

    initial = options.initial
    watchFile dirname
    initial = 'created'

    # console.log("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")
    # console.log(JSON.stringify(allWatchers, null, '  '))
    # console.log("================" + fs.setMaxListeners)
    # console.log("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")

    # return a function that will unwatch all watched files
    ->
        for key of watchedFiles
            unwatchFile key

allWatchers = {}