import crypto from 'crypto'

import bodyParser from 'body-parser'
import cookieParser from 'cookie-parser'

import express from 'express'

import { createStatusRouter, PingRouter } from './middlewares.js'
import {
    createDatabase,
    createProblem,
    createSolution,
    getProblem,
    getProblems,
    getSolutions,
    getUser,
    getUsers,
} from './db/database.js'
import { initialDatabaseValue } from './db/example-data.js'

export async function createApiRouter() {
    const sessions = {
        store: {},
        createSession(username) {
            const sid = crypto.randomBytes(10).toString('hex')
            this.store[sid] = username
            return sid
        },
        getUserForSession(sid) {
            return this.store[sid] ?? null
        },
    }

    const db = createDatabase('./db.local.json', initialDatabaseValue)

    async function getRequestUser(req) {
        const userId = sessions.getUserForSession(req.cookies.sid)
        if (!userId) {
            return null
        }

        const user = await getUser(db, userId)

        return user
    }

    const r = express.Router()

    r.use(bodyParser.json())
    r.use(cookieParser())

    r.use('/api/status', createStatusRouter())
    r.use('/api/ping', new PingRouter())

    r.get('/api/current-user', async (req, res) => {
        res.json(await getRequestUser(req))
    })

    r.post('/api/login', async (req, res) => {
        const { username } = req.body

        const user = await getUser(db, username)
        if (!user) {
            res.sendStatus(403)
            return
        }

        res.cookie('sid', sessions.createSession(username), { maxAge: 1000 * 60 * 60 * 24 * 7 })
        res.json({ status: 'ok' })
    })

    r.post('/api/logout', (req, res) => {
        res.cookie('sid', '', { expires: new Date() })
        res.json({ status: 'ok' })
    })

    r.get('/api/users', async (req, res) => {
        const requestUser = await getRequestUser(req)
        if (requestUser.role !== 'admin' && requestUser.role !== 'moderator') {
            res.sendStatus(401)
            return
        }

        const users = await getUsers(db)
        res.json(users)
    })

    r.get('/api/problems', async (req, res) => {
        res.json(await getProblems(db))
    })

    r.get('/api/problem/:id', async (req, res) => {
        res.json(await getProblem(db, req.params.id))
    })

    r.post('/api/problem', async (req, res) => {
        const user = await getRequestUser(req)
        if (!user) {
            res.sendStatus(401)
            return
        }
        if (user.role !== 'admin' && user.role !== 'moderator') {
            res.sendStatus(401)
            return
        }

        const id = await createProblem(db, {
            content: req.body.content,
            createBy: user.username,
        })

        res.json(id)
    })

    r.get('/api/solutions', async (req, res) => {
        let queryUserId = req.query.user
        let queryProblemId = req.query.problem

        const requestUser = await getRequestUser(req)
        if (!requestUser) {
            res.sendStatus(401)
            return
        }

        // if current user is not an administrator then force the user query to current user
        if (requestUser.role !== 'admin' && requestUser.role !== 'moderator') {
            queryUserId = requestUser.username
        }

        res.json(await getSolutions(db, { userId: queryUserId, problemId: queryProblemId }))
    })

    r.post('/api/solution', async (req, res) => {
        const user = await getRequestUser(req)
        if (!user) {
            res.sendStatus(401)
            return
        }

        await createSolution(db, {
            userId: user.username,
            problemId: req.body.problemId,
            content: req.body.content,
        })

        res.send({ status: 'ok' })
    })

    r.get('/api/user/:id', async (req, res) => {
        const requestUser = await getRequestUser(req)
        if (!requestUser) {
            res.sendStatus(401)
            return
        }
        if (requestUser.role !== 'admin' && requestUser.role !== 'moderator') {
            res.sendStatus(401)
            return
        }

        const requestedUser = await getUser(db, req.params.id)
        if (!requestedUser) {
            res.sendStatus(404)
            return
        }

        res.json(requestedUser)
    })

    return r
}