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import { join, dirname, resolve } from 'path'
import { Low, JSONFile } from 'lowdb'
import { fileURLToPath } from 'url'
import crypto from 'crypto'
const __dirname = dirname(fileURLToPath(import.meta.url))
const file = join(__dirname, '../data', 'db.json')
let adapter
let db
const init = async () => {
adapter = new JSONFile(file)
db = new Low(adapter)
await db.read()
db.data ||= { rooms: {} }
await db.write()
}
const read = async () => {
await db.read()
return db.data
}
const write = async (obj) => {
await db.read()
let roomHash
switch (obj.type) {
case 'introduction':
case 'expense':
roomHash = _getHash(obj.roomId)
db.data.rooms[roomHash] ||= { events: [] }
db.data.rooms[roomHash].events.push(obj)
break
default:
throw new Error('Invalid type for db.write()')
break
}
await db.write()
}
const undo = async (roomId) => {
const roomHash = _getHash(roomId)
await db.read()
db.data.rooms[roomHash] ||= { events: [] }
db.data.rooms[roomHash].events.pop()
await db.write()
}
const reset = async (roomId) => {
const roomHash = _getHash(roomId)
await db.read()
db.data.rooms[roomHash] ||= { events: [] }
db.data.rooms[roomHash].events = db.data.rooms[roomHash].events.filter(
(e) => {
return !(e.type === 'expense' || e.type === 'transaction')
}
)
await db.write()
}
const fullreset = async (roomId) => {
const roomHash = _getHash(roomId)
await db.read()
db.data.rooms[roomHash] ||= { events: [] }
delete db.data.rooms[roomHash]
await db.write()
}
const getUsers = async (roomId) => {
const roomHash = _getHash(roomId)
const data = await read()
let userIds = []
data.rooms[roomHash] ||= { events: [] }
data.rooms[roomHash].events.forEach((event) => {
if (event.type === 'introduction') {
userIds.push(event.userId)
}
})
return userIds
}
const getEventLog = async (roomId, limit) => {
const roomHash = _getHash(roomId)
const data = await read()
data.rooms[roomHash] ||= { events: [] }
return data.rooms[roomHash].events.slice(-(limit || 4))
}
const getBalance = async (roomId) => {
const roomHash = _getHash(roomId)
const data = await read()
let balance = {
userIds: [],
}
data.rooms[roomHash] ||= { events: [] }
data.rooms[roomHash].events.forEach((event) => {
switch (event.type) {
case 'introduction':
balance.userIds.push(event.userId)
balance[event.userId] = {
totalSpent: 0,
spentForUserId: {},
}
break
case 'expense':
balance[event.userId].totalSpent += event.data.amount
balance.userIds.forEach((userId) => {
balance[event.userId].spentForUserId[userId] ||= 0
balance[event.userId].spentForUserId[userId] +=
event.data.amount / balance.userIds.length
})
break
default:
break
}
})
return balance
}
const _getHash = (string) => {
return crypto.createHash('sha256').update(string, 'utf8').digest('hex')
}
export default {
init: init,
read: read,
write: write,
undo: undo,
reset: reset,
fullreset: fullreset,
getUsers: getUsers,
getEventLog: getEventLog,
getBalance: getBalance,
}
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