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

let Tag = module.exports = {}


Tag.removeTagFromNote = (userId, tagId) => {
	return new Promise((resolve, reject) => {
		db.promise()
		.query(`DELETE FROM note_tag 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 note_tag 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 note_tag (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 tag (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) => {

		//Update last opened date of note
		const now = Math.round((+new Date)/1000)
		db.promise()
		.query('UPDATE note SET opened = ? WHERE id = ? AND user_id = ? LIMIT 1', [now, noteId, userId])
		.then((rows, fields) => {})

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

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

	return new Promise((resolve, reject) => {
		db.promise()
		.query(`SELECT tag.text FROM note_tag 
				JOIN tag ON note_tag.tag_id = tag.id
				JOIN note ON note_tag.note_id = note.id
				WHERE note_tag.user_id = ?
				AND note_tag.tag_id NOT IN (
					SELECT note_tag.tag_id FROM note_tag WHERE note_tag.note_id = ?
				)
				GROUP BY tag.text, note.updated
				ORDER BY note.updated DESC
				LIMIT 8;`, [userId, noteId])
		.then((rows, fields) => {
			resolve(rows[0]) //Return found tags
		})
		.catch(console.log)
	})
}