import QuickTemplate from './'
import parseTree from './parseTree'
import {schema, matchesSchema} from './schema'
import extend from 'smart-extend'
import IS from '../checks'
NOT_DEEP_KEYS = ['relatedInstance','related','data']
NOT_KEYS = ['children','_childRefs']

export default extendTemplate = (currentOpts, newOpts, globalOpts)->
	if globalOpts then globalOptsTransform = options: (opts)-> extend(opts, globalOpts)
	if IS.array(newOpts)
		newOpts = parseTree(newOpts, false)
	else if newOpts and not matchesSchema(newOpts)
		newOpts = options:newOpts


	output = extend.deep.nullDeletes.notKeys(NOT_KEYS).notDeep(NOT_DEEP_KEYS).transform(globalOptsTransform).clone(currentOpts, newOpts)
	currentChildren = currentOpts.children
	newChildren = newOpts?.children or []
	output.children = []

	### istanbul ignore next ###
	if IS.array(newChildren)
		maxLength = Math.max(currentChildren.length, newChildren.length)
		index = -1
		while ++index isnt maxLength
			needsTemplateWrap = noChanges = false
			currentChild = currentChildren[index]
			newChild = newChildren[index]
			newChildProcessed = switch
				when IS.template(newChild) then newChild
				when IS.array(newChild) then needsTemplateWrap = parseTree(newChild)
				when IS.string(newChild) then needsTemplateWrap = {type:'text', options:{text:newChild}}
				when not newChild and not globalOpts then noChanges = true
				else needsTemplateWrap = newChild or true


			if noChanges
				newChildProcessed = currentChild
			
			else if needsTemplateWrap
				newChildProcessed = 
					if currentChild
						currentChild.extend(newChildProcessed, globalOpts)
					else
						new QuickTemplate(extend.clone(schema, newChildProcessed))

			output.children.push newChildProcessed
	
	
	else if IS.object(newChildren)
		newChildren = extend.allowNull.clone newChildren
		output.children = extendByRef(newChildren, currentChildren, globalOpts)
		remainingNewChildren = newChildren
		
		for ref,newChild of remainingNewChildren
			newChildProcessed = if IS.objectPlain(newChild) and not IS.template(newChild) then newChild else parseTree(newChild)
			output.children.push new QuickTemplate newChildProcessed
			delete remainingNewChildren[ref]

	return output




extendByRef = (newChildrenRefs, currentChildren, globalOpts)-> if not currentChildren.length then currentChildren else
	output = []
	
	for currentChild in currentChildren
		newChild = newChildrenRefs[currentChild.ref]
		if newChild
			newChildProcessed = currentChild.extend(newChild, globalOpts)
			delete newChildrenRefs[currentChild.ref]
		
		else if newChild is null
			delete newChildrenRefs[currentChild.ref]
			continue
		
		else
			newChildProcessed = switch
				when globalOpts then currentChild.extend(null, globalOpts)
				when Object.keys(newChildrenRefs).length then currentChild.extend()
				else currentChild

		newChildProcessed.children = extendByRef(newChildrenRefs, newChildProcessed.children)
		output.push(newChildProcessed)

	return output