let db = require('@config/database')

let Tag = module.exports = {}


Tag.removeTagFromNote = (userId, tagId) => {
	return new Promise((resolve, reject) => {
		db.promise()
		.query(`DELETE FROM notes_tags WHERE id = ? AND user_id = ? LIMIT 1;`, [tagId, userId])
		.then((rows, fields) => {
			resolve(rows[0]) //Return new ID
		})
		.catch(console.log)
	})
}

Tag.addToNote = (userId, noteId, tagText) => {
	return new Promise((resolve, reject) => {

		//Lookup tag
		Tag.lookup(tagText)
		.then( lookup => {
			
			//Tag does not exist, insert new tag, then associate it with a note
			if(lookup.length == 0){
				//Insert new tag
				Tag.add(tagText)
				.then( newTagId => {
					Tag.associateWithNote(userId, noteId, newTagId)
					.then( result => {
						resolve(result)
					})
				})
			}

			//Tag already exists, associate it with a note
			if(lookup.length > 0){
				Tag.associateWithNote(userId, noteId, lookup[0].id)
				.then( result => {
					resolve(result)
				})
			}

		})
	})
}

Tag.associateWithNote = (userId, noteId, tagId) => {
	return new Promise((resolve, reject) => {

		//Check if tag already exists on note before adding note
		db.promise()
		.query(`SELECT * FROM notes_tags WHERE note_id = ? AND tag_id = ? AND user_id = ?;`, [noteId, tagId, userId])
		.then((rows, fields) => {

			//If matching tag does not exist on note
			if(rows[0].length == 0){

				//Add tag to note
				db.promise()
				.query(`INSERT INTO notes_tags (note_id, tag_id, user_id) VALUES (?,?,?);`, [noteId, tagId, userId])
				.then((rows, fields) => {
					resolve(rows[0]) 
				})
				.catch(console.log)
			} else {

				reject('Error: Tag already exists on note.')
			}
		})
		.catch(console.log)
	})
}

Tag.add = (tagText) => {
	return new Promise((resolve, reject) => {
		db.promise()
		.query(`INSERT INTO tags (text, hash) VALUES (?,?);`, [tagText,0])
		.then((rows, fields) => {
			resolve(rows[0].insertId) //Return new ID
		})
		.catch(console.log)
	})
}

Tag.get = (userId, noteId) => {
	return new Promise((resolve, reject) => {
		db.promise()
		.query(`SELECT notes_tags.id, tags.text FROM notes_tags
				JOIN tags ON (tags.id = notes_tags.tag_id)
				WHERE user_id = ? AND note_id = ?;`, [userId, noteId])
		.then((rows, fields) => {
			resolve(rows[0]) //Return all tags found by query
		})
		.catch(console.log)
	})
}

Tag.string = (userId, noteId) => {
	return new Promise((resolve, reject) => {
		Tag.get(userId, noteId).then(tagArray => {

			let tagString = ''
			tagArray.forEach( (tag, i) => {
				if(i > 0){ tagString += ',' }
				tagString += tag.text
			})
			//Output comma delimited list of tag strings
			resolve(tagString)

		})
	})
}

Tag.lookup = (tagText) => {
	return new Promise((resolve, reject) => {
		db.promise()
		.query(`SELECT * FROM tags WHERE text = ?;`, [tagText])
		.then((rows, fields) => {
			resolve(rows[0]) //Return all tags found by query
		})
		.catch(console.log)
	})
}

//Suggest note tags - don't suggest tags already on note
Tag.suggest = (userId, noteId, tagText) => {

	tagText += '%'

	return new Promise((resolve, reject) => {
		db.promise()
		.query(`SELECT text FROM notes_tags 
				JOIN tags ON notes_tags.tag_id = tags.id
				WHERE notes_tags.user_id = ?
				AND tags.text LIKE ?
				AND notes_tags.tag_id NOT IN (
					SELECT notes_tags.tag_id FROM notes_tags WHERE notes_tags.note_id = ?
				)
				GROUP BY text
				LIMIT 6;`, [userId, tagText, noteId])
		.then((rows, fields) => {
			resolve(rows[0]) //Return new ID
		})
		.catch(console.log)
	})
}