let ProcessText = module.exports = {}

ProcessText.removeHtml = (string) => {

	if(string == undefined || string == null || string.length == 0){
		return ''
	}

	return string
		.replace(/&[[#A-Za-z0-9]+A-Za-z0-9]+;/g,' ') //Rip out all HTML entities
		.replace(/<[^>]+>/g, ' ') //Rip out all HTML tags
		.replace(/\s+/g, ' ') //Remove all whitespace
		.trim()
}

ProcessText.getUrlsFromString = (string) => {
	const urlPattern = /(?:(?:https?|ftp|file):\/\/|www\.|ftp\.)(?:\([-A-Z0-9+&@#/%=~_|$?!:,.]*\)|[-A-Z0-9+&@#/%=~_|$?!:,.])*(?:\([-A-Z0-9+&@#/%=~_|$?!:,.]*\)|[A-Z0-9+&@#/%=~_|$])/igm
	return string.match(urlPattern)
}

/* 
	Pulls out title and subtext of note 
		+ Title is always first line
		+ Empty lines are skipped
		+ URLs are turned into links
		+ All URLs are givent the target="_blank" property
		+ Lists are given extra display characters
		+ If note starts as a list, skip the title
*/

ProcessText.deduceNoteTitle = (inString) => {

	let title = '' //Title of note
	let sub = '' //sub text below note

	if(!inString || inString == null || inString.length == 0){
		return {title, sub}
	}

	//Remove inline styles that may be added by editor
	inString = inString.replace(/style=".*?"/g,'')

	//Match full line and closing tag or just closing tag
	let lines = inString.match(/[<[a-zA-Z0-9]+>(.*?)<\/[a-zA-Z0-9]+>|<\/[a-zA-Z0-9>]+?>/g)
	if(lines == null){ lines = [inString] }
	//.match(/[^\r\n]+/g) //Match return or newline

	// console.log(lines)

	let finalLines = []

	const startTags = ['<ol','<li','<ul']
	const endTags = ['</o','</l','</u']

	let totalLines = Math.min(lines.length, 6)
	let charLimit = 250
	let listStart = false
	let noTitleJustList = false

	for(let i=0; i < totalLines; i++){

		//Just in case 'i' gets bigger than array
		if(lines[i] === undefined){
			continue
		}

		//Various empty chars are possible
		const cleanLine = ProcessText.removeHtml(lines[i])
			.replace('<br>','')
			.trim()
		const lineStart = lines[i].trim().substring(0, 3)
		charLimit -= cleanLine.length

		//Close out list if char limit is hit
		if(charLimit <= 0 && listStart){
			finalLines.push(lines[i])
			break
		}

		//Images appear as empty, push em!
		if(cleanLine.length == 0 && lines[i].indexOf('<img') != -1){
			finalLines.push(lines[i])
			continue
		}

		//Check if note starts with a list, don't include title, just show list
		if(finalLines.length == 0 && startTags.includes(lineStart)){
			noTitleJustList = true
		}

		//Empty line, may be a list open or close
		if(cleanLine.length == 0 && (startTags.includes(lineStart) || endTags.includes(lineStart) )){
			if(listStart == false){
				charLimit = 400 //Double size for list notes
			}
			finalLines.push(lines[i])
			totalLines++
			listStart = true
			continue
		}

		//If line is part of a list, up counter, we want the whole list
		if(startTags.includes(lineStart)){
			totalLines++
		}

		//Skip empty lines
		if(!cleanLine || cleanLine.length == 0){
			totalLines++
			continue
		}

		//turn urls into links, don't process if its already an <a href=
		const containsUrls = ProcessText.getUrlsFromString(cleanLine)
		if(containsUrls && containsUrls.length == 1 && lines[i].indexOf('</a>') == -1){
			const url = containsUrls[0]
			lines[i] = lines[i].replace(url, `<a href="${url}">${url}</a>`)
		}

		//Insert target=_blank into links if set, do it for every link in line
		if(lines[i].indexOf('</a>') > 0){
			lines[i] = lines[i].replace(/<a /g, '<a target="_blank" ')
		}

		//Limit output characters
		//Check character limit
		if(charLimit <= 0 && listStart == false){

			//Cut the string down to character limit
			const cutString = lines[i].substring(0, lines[i].length+charLimit)
			//Find last space and cut off everything after it
			let cleanCutString = cutString.substring(0, cutString.lastIndexOf(' '))

			//Some strings may not contain a space resulting in no string
			if(cleanCutString.length == 0){
				cleanCutString = cutString
			}

			finalLines.push(cleanCutString + '...')
			break;
		}

		finalLines.push(lines[i])

	}

	//Pull out title if its not an empty string
	if(ProcessText.removeHtml(finalLines[0]).trim().replace('&nbsp','').length > 0 && !noTitleJustList){
		title = finalLines.shift()
	}
	
	sub = finalLines.join('')

	//Return final display lengths
	let titleLength = ProcessText.removeHtml(title).trim().replace('&nbsp','').length
	let subtextLength = ProcessText.removeHtml(sub).trim().replace('&nbsp','').length


	return { title, sub, titleLength, subtextLength }
}