const crypto = require('crypto')

const Note = require('@models/Note')

const db = require('@config/database')
const Auth = require('@helpers/Auth')
const cs = require('@helpers/CryptoString')

let User = module.exports = {}

//Login a user, if that user does not exist create them
//Issues login token
User.login = (username, password) => {
	return new Promise((resolve, reject) => {

		const lowerName = username.toLowerCase();

		db.promise()
		.query('SELECT * FROM user WHERE username = ? LIMIT 1', [lowerName])
		.then((rows, fields) => {

			// Create New Account 
			//
			if(rows[0].length == 0){
				User.create(lowerName, password)
				.then( ({token, userId}) => {
					return resolve({ token, userId })
				})
			}

			// Login User
			//
			if(rows[0].length == 1){

				//Pull out user data from database results
				const lookedUpUser = rows[0][0]

				//hash the password and check for a match
				// const salt = new Buffer(lookedUpUser.salt, 'binary')
				const salt = Buffer.from(lookedUpUser.salt, 'binary')
				crypto.pbkdf2(password, salt, lookedUpUser.iterations, 512, 'sha512', function(err, delivered_key){
					if(delivered_key.toString('hex') === lookedUpUser.password){

						User.generateMasterKey(lookedUpUser.id, password)
						.then( result => User.getMasterKey(lookedUpUser.id, password))
						.then(masterKey => {

							User.generateKeypair(lookedUpUser.id, masterKey)
							.then(({publicKey, privateKey}) => {

								//Passback a json web token
								const token = Auth.createToken(lookedUpUser.id, masterKey)
								resolve({ token: token, userId:lookedUpUser.id })

							})
						})

					} else {

						reject('Password does not match database')
					}
				})
			}
		})
		.catch(console.log)

	})
}

//Create user account
//Issues login token
User.create = (username, password) => {

	//For some reason, username won't get into the promise. But password will @TODO figure this out
	const lowerName = username.toLowerCase().trim()

	return new Promise((resolve, reject) => {

		db.promise()
		.query('SELECT * FROM user WHERE username = ? LIMIT 1', [lowerName])
		.then((rows, fields) => {

			if(rows[0].length === 0){ //No users returned, create new one. Start with hashing password

				//Params for hash function
				let shasum = crypto.createHash('sha512') //Prepare Hash
				const ran = parseInt(Date.now()) //Get current time in miliseconds
				const semiRandomInt = Math.floor(Math.random()*11) //Grab a random number
				const otherRandomInt = (ran*semiRandomInt+ran)*semiRandomInt-ran //Mix things up a bit
				shasum.update(''+otherRandomInt) //Update Hasd

				const saltString = shasum.digest('hex')
				const salt = Buffer.from(saltString, 'binary') //Generate Salt hash
				const iterations = 25000

				crypto.pbkdf2(password, salt, iterations, 512, 'sha512', function(err, delivered_key) {

					//Create new user object with freshly salted password
					var currentDate = new Date().toISOString().slice(0, 19).replace('T', ' ');
					var new_user = {
						username: lowerName,
						password: delivered_key.toString('hex'),
						salt: salt,
						iterations: iterations,
						last_login: currentDate,
						created: currentDate
					};

					let userId = null
					let newMasterKey = null

					db.promise()
					.query('INSERT INTO user SET ?', new_user)
					.then((rows, fields) => {

						userId = rows[0].insertId
						return User.generateMasterKey(userId, password)
					})
					.then( result => {

						return User.getMasterKey(userId, password)
					})
					.then(masterKey => {
						newMasterKey = masterKey
						return User.generateKeypair(userId, newMasterKey)
					})
					.then(({publicKey, privateKey}) => {

						const token = Auth.createToken(userId, newMasterKey)
						return resolve({token, userId})
					})
					.catch(console.log)
				})
			} else {
				return reject('Username already in use.')
			}//END user create
		})
		.catch(console.log)

		
	})
}

//Counts notes, pinned notes, archived notes, shared notes, unread notes, total files and types
User.getCounts = (userId) => {
	return new Promise((resolve, reject) => {

		let countTotals = {}

		db.promise().query(
			`SELECT
				SUM(archived = 1 && share_user_id IS NULL && trashed = 0) AS archivedNotes,
				SUM(trashed = 1) AS trashedNotes,
				SUM(share_user_id IS NULL && trashed = 0) AS totalNotes,
				SUM(share_user_id != ? && trashed = 0) AS sharedToNotes,
				SUM( (share_user_id != ? && opened IS null && trashed = 0) || (share_user_id != ? && note_raw_text.updated > opened && trashed = 0) ) AS unreadNotes
			FROM note 
			LEFT JOIN note_raw_text ON (note_raw_text.id = note.note_raw_text_id)
			WHERE user_id = ?`, [userId, userId, userId, userId])
		.then( (rows, fields) => {

			Object.assign(countTotals, rows[0][0]) //combine results
			//
			// @TODO - Figured out if this is useful
			// We want, notes shared with user and note user has shared
			//
			return db.promise().query(
				`SELECT count(id) AS sharedFromNotes 
				FROM note WHERE shared = 2 AND user_id = ? AND trashed = 0`, [userId]
			)
		})
		.then( (rows, fields) => {

			Object.assign(countTotals, rows[0][0]) //combine results

			return db.promise().query(
				`SELECT
					SUM(attachment_type = 1) as linkFiles,
					SUM(attachment_type != 1) as otherFiles,
					COUNT(id) as totalFiles
				FROM attachment WHERE visible = 1
				AND user_id = ?
				`, [userId]
			)
		}).then( (rows, fields) => {

			Object.assign(countTotals, rows[0][0]) //combine results

			//Convert everything to an int or 0
			Object.keys(countTotals).forEach( key => {
				const count = parseInt(countTotals[key])
				countTotals[key] = count ? count : 0
			})

			resolve(countTotals)
		})

	})
}

User.generateMasterKey = (userId, password) => {
	return new Promise((resolve, reject) => {

		if(!userId || !password){
			reject('Need userId and password to generate key')
		}

		db.promise()
			.query('SELECT count(id) as total FROM user_key WHERE user_id = ?', [userId])
			.then((rows, fields) => {

				//Entry already exists, you good.
				if(rows[0][0]['total'] > 0){
					return resolve(true)
					// throw new Error('User Encryption key already exists')
				} else {
					// Generate user key, its big and random
					const masterPassword = cs.createSmallSalt()

					//Generate a salt because it wants it
					const salt = cs.createSmallSalt()

					// Encrypt master password
					const encryptedMasterPassword = cs.encrypt(password, salt, masterPassword)

					const created = Math.round((+new Date)/1000)

					db.promise()
					.query(
						'INSERT INTO user_key (`user_id`, `salt`, `key`, `created`) VALUES (?, ?, ?, ?);', 
						[userId, salt, encryptedMasterPassword, created]
					)
					.then(results => {
						return resolve(true)
					})
				}

			})
			.catch(error => {
				console.log('Create Master Password Error')
				console.log(error)
			})

	})
}

User.getMasterKey = (userId, password) => {

	if(!userId || !password){
		reject('Need userId and password to fetch key')
	}

	return new Promise((resolve, reject) => {

		db.promise().query('SELECT * FROM user_key WHERE user_id = ? LIMIT 1', [userId])
		.then((rows, fields) => {

			const row = rows[0][0]

			if(!rows[0] || rows[0].length == 0 || rows[0][0] == undefined){
				return reject('Row or salt or something not set')
			}

			const masterKey = cs.decrypt(password, row['salt'], row['key'])

			if(masterKey == null){
				return reject('Unable to decrypt key')
			}

			return resolve(masterKey)

		})

	})
}

User.generateKeypair = (userId, masterKey) => {

	let publicKey = null
	let privateKey = null

	return new Promise((resolve, reject) => {
		db.promise().query('SELECT * FROM user_key WHERE user_id = ?', [userId])
		.then((rows, fields) => {

			const row = rows[0][0]

			const salt = row['salt']
			publicKey = row['public_key']
			privateKey = row['private_key_encrypted']

			if(row['public_key'] == null){
				const keyPair = crypto.generateKeyPairSync('rsa', { 
					modulusLength: 1024, 
					publicKeyEncoding: { 
						type: 'spki',
						format: 'pem'
					}, 
					privateKeyEncoding: { 
						type: 'pkcs8',
						format: 'pem'
					} 
				})

				publicKey = keyPair.publicKey
				privateKey = keyPair.privateKey
				const privateKeyEncrypted = cs.encrypt(masterKey, salt, privateKey)

				db.promise()
				.query(
					'UPDATE user_key SET `public_key` = ?, `private_key_encrypted` = ? WHERE user_id = ?;', 
					[publicKey, privateKeyEncrypted, userId]
				)
				.then((rows, fields)=>{
					
					return resolve({publicKey, privateKey})

				})

			} else {

				//Decrypt private key
				privateKey = cs.decrypt(masterKey, salt, privateKey)

				return resolve({publicKey, privateKey})
			}
		})
	})
}

User.getPublicKey = (userId) => {
	return new Promise((resolve, reject) => {
		db.promise().query('SELECT public_key FROM user_key WHERE user_id = ?', [userId])
		.then((rows, fields) => {

			const row = rows[0][0]
			return resolve(row['public_key'])
			
		})
	})
}

User.getPrivateKey = (userId, masterKey) => {
	return new Promise((resolve, reject) => {
		db.promise().query('SELECT salt, private_key_encrypted FROM user_key WHERE user_id = ?', [userId])
		.then((rows, fields) => {

			const row = rows[0][0]

			const salt = row['salt']
			privateKey = row['private_key_encrypted']

			//Decrypt private key
			privateKey = cs.decrypt(masterKey, salt, privateKey)

			return resolve(privateKey)
		})
	})
}

User.getByUserName = (username) => {
	return new Promise((resolve, reject) => {
		db.promise().query('SELECT * FROM user WHERE username = ? LIMIT 1', [username.toLowerCase()])
		.then((rows, fields) => {
			resolve(rows[0][0])
		})
	})
}

User.deleteUser = (userId, password) => {

	//Verify user is correct by decryptig master key with password
	
	let deletePromises = []

	let noteDelete = db.promise().query(`
		DELETE note, note_raw_text 
		FROM note
		JOIN note_raw_text ON (note_raw_text.id = note.note_raw_text_id)
		WHERE note.user_id = ?
	`,[userId])
	deletePromises.push(noteDelete)

	let userDelete = db.promise().query(`
		DELETE FROM user WHERE id = ?
	`,[userId])
	deletePromises.push(userDelete)

	let tables = ['user_key', 'user_encrypted_search_index', 'attachment']
	tables.forEach(tableName => {

		const query = `DELETE FROM ${tableName} WHERE user_id = ?`
		const deleteQuery = db.promise().query(query, [userId])
		deletePromises.push(deleteQuery)
	})

	return Promise.all(deletePromises)
}

User.keyPairTest = (testUserName = 'genMan', password = '1', printResults) => {
	return new Promise((resolve, reject) => {

		let masterKey = null
		let testUserId = null


		const randomUsername = Math.random().toString(36).substring(2, 15);
		const randomPassword = '1'

		User.login(testUserName, password)
		.then( ({ token, userId }) => { 
			testUserId = userId

			if(printResults) console.log('Test: Create/Login User '+testUserName+' - Pass')

			return User.getMasterKey(testUserId, password) 
		})
		.then(newMasterKey => {
			masterKey = newMasterKey

			if(printResults) console.log('Test: Generate/Decrypt Master Key - Pass')

			return User.generateKeypair(testUserId, masterKey)
		})
		.then(({publicKey, privateKey}) => {
			
			const publicKeyMessage = 'Test: Public key decrypt - Pass'
			const privateKeyMessage = 'Test: Private key decrypt - Pass'

			//Encrypt Message with private Key
			const privateKeyEncrypted = crypto.privateEncrypt(privateKey, Buffer.from(privateKeyMessage, 'utf8')).toString('base64')
			const decryptedPrivate = crypto.publicDecrypt(publicKey, Buffer.from(privateKeyEncrypted, 'base64'))
			//Conver back to a string
			if(printResults) console.log(decryptedPrivate.toString('utf8'))

			//Encrypt with public key
			const pubEncrMsc = crypto.publicEncrypt(publicKey, Buffer.from(publicKeyMessage, 'utf8')).toString('base64')
			const publicDeccryptMessage = crypto.privateDecrypt(privateKey, Buffer.from(pubEncrMsc, 'base64') )
			//Convert it back to string
			if(printResults) console.log(publicDeccryptMessage.toString('utf8'))

			resolve({testUserId, masterKey})
		})
	})
}