const jwt = require("jsonwebtoken")
const crypto = require("node:crypto")
const security = require("../modules/security")
const tokenRepo = require("../repositories/refreshTokensRepo")
const { DefaultError } = require("../errors/errors")

const privateKey = security.readPrivateKey()
const publicKey = security.readPublicKey()

async function signToken(user) {
    try {
        const payload = {
            id: user.id,
            identifier: user.identifier,
            displayName: user.displayName,
            avatarUrl: user.avatarUrl,
            role: user.role
        }
        const token = await jwt.sign(payload, privateKey, {
            algorithm: "RS256",
            issuer: process.env.FQDN,
            expiresIn: parseInt(process.env.ACCESS_TOKEN_EXPIRY)
        })
        return token
    } catch (error) {
        throw error
    }
}

async function verifyAccessToken(token) {
    try {
        const result = jwt.verify(token, publicKey, {
            algorithms: ["RS256"],
            issuer: process.env.FQDN
        })
        return result
    } catch (error) {
        throw error
    }
}

async function signRefreshToken(userId) {
    try {
        const isTokenExisting = await tokenRepo.findByUserId(userId)
        if (!Array.isArray(isTokenExisting)) {
            await tokenRepo.removeByUserId(userId)
        }
        const now = Date.now()
        const expiresIn = parseInt(process.env.REFRESH_TOKEN_EXPIRY)
        const expiresAtInMs = new Date(now + (expiresIn * 1000))
        const token = jwt.sign(
            { userId },
            privateKey,
            {
                algorithm: "RS256",
                issuer: process.env.FQDN,
                expiresIn: expiresIn
            }
        )
        const hash = crypto.createHash("sha256").update(token).digest("hex")
        await tokenRepo.create(userId, hash, expiresAtInMs)
        return token
    } catch (error) {
        throw error
    }
}

async function revokeRefreshToken(token) {
    try {
        return await tokenRepo.removeByTokenHash(token)
    } catch (error) {
        throw error
    }
}

async function verifyRefreshToken(token) {
    try {
        const result = jwt.verify(token, publicKey, {
            algorithms: ["RS256"],
            issuer: process.env.FQDN
        })
        if (!result) {
            throw new DefaultError(500, "Internal Server Error")
        }
        const hash = crypto.createHash("sha256").update(token).digest("hex")
        const refreshTokenInDb = await tokenRepo.findByTokenHash(hash)
        if (refreshTokenInDb == null) {
            throw new DefaultError(403, "Bad refresh token", "Refresh token doesn't exists")
        }
        return result
    } catch (error) {
        throw error
    }
}

async function verifyAccessTokenFromServer(token) {
    // TO-DO: Integrate server federation
}

module.exports = {
    signToken,
    signRefreshToken,
    verifyAccessToken,
    revokeRefreshToken,
    verifyRefreshToken,
}