nowpad/lib/public/common.coffee

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(->
	# Scope
	scope = if window? then window else exports
	
	# Requirements
	diff_match_patch = if window? then window.diff_match_patch else require(__dirname+'/diff_match_patch.js').diff_match_patch

	# Prepare
	dmp = new diff_match_patch()

	# Define
	scope.nowpadCommon =
		
		# List
		List: class
			# Storage
			items: {}
			length: 0

			# Constructor
			constructor: ->
				@items = {}

			# For each
			forEach: (callback) ->
				for key,value of @items
					callback value

			# Fetch an used id
			generateId: ->
				while true
					id = String Math.floor Math.random()*1000
					if typeof @items[id] is 'undefined'
						break
				return id
			
			# Add a new item to the list
			add: (item) ->
				@items[item.id] = item
				@length++
			
			# Get an item from the list
			get: (id) ->
				return @items[id] || false
			
			# Does the item exist?
			has: (id) ->
				return @items[id]?
			
			# Set an item from the list
			set: (id,item) ->
				if typeof @items[id] is 'undefined'
					throw new Error 'an item with the id of ['+id+'] does not exist'
				@items[id] = item
			
			# Remove an item from the list
			remove: (id) ->
				if @has id
					item = @get id
					delete @items[id]
					@length--
					return item
				else
					return false
			
			# Destroy an item from the list
			destroy: (id) ->
				if @has id
					item = @get id
					@remove id
					item.destroy()
				else
					return false

		# Create Patch
		createPatch: (before,after) ->
			patches = dmp.patch_make(before,after)
			patchesStr = dmp.patch_toText(patches)
			return patchesStr
		
		# Apply Patch
		applyPatch: (_patchesStr,_value,_selectionRange) ->
			# Prepare
			patches = dmp.patch_fromText(_patchesStr)
			pass = false
			selectionRange = {}

			# Ensure
			_selectionRange or= {}
			selectionRange.selectionStart = _selectionRange.selectionStart || 0
			selectionRange.selectionEnd = _selectionRange.selectionEnd || _selectionRange.selectionStart

			# Apply
			result = dmp.patch_apply(patches,_value)
			value = result[0]
			pass = result[1][0] || false

			# Decode
			if selectionRange.selectionStart or selectionRange.selectionEnd
				
				# Cycle through patches
				for patch in patches
					# Prepare
					start = 0
					mod = 0

					# Handle
					for diff in patch.diffs
						switch diff[0]
							when -1
								mod -= diff[1].length
							when 1
								mod += diff[1].length
					
					# Adjust
					if patch.diffs[0][0] is 0
						start = patch.diffs[0][1].length
					start += patch.start1
					
					# Apply
					if start < selectionRange.selectionStart
						selectionRange.selectionStart += mod
					if start < selectionRange.selectionStart or start < selectionRange.selectionEnd
						selectionRange.selectionEnd += mod
				
					# Log
					console.log(
						'selectionRange:',
						[_selectionRange.selectionStart,_selectionRange.selectionEnd],
						[selectionRange.selectionStart,selectionRange.selectionEnd],
						[patch.start1,start,mod]
					)

			# Return
			return {
				pass: pass
				value: value
				selectionRange: selectionRange
			}
)()