// import * as secp256k1 from '@noble/secp256k1'
// import { Buffer } from 'buffer'
const secp256k1 = require('@noble/secp256k1');
const crypto = require('crypto')

function generatePrivateKey() {
    return Buffer.from(secp256k1.utils.randomPrivateKey()).toString('hex')
}

function getPublicKey(privateKey) {
    return Buffer.from(secp256k1.schnorr.getPublicKey(privateKey)).toString('hex')
}


function serializeEvent(evt) {
    return JSON.stringify([
        0,
        evt.pubkey,
        evt.created_at,
        evt.kind,
        evt.tags,
        evt.content
    ])
}


function getEventHash(event) {
    let eventHash = crypto.createHash('sha256')
        .update(Buffer.from(serializeEvent(event)))
        .digest()
    return Buffer.from(eventHash).toString('hex')
}


async function signEvent(event, key) {
    return Buffer.from(
        await secp256k1.schnorr.sign(getEventHash(event), key)
    ).toString('hex')
}

function validateEvent(event) {
    if (event.id !== getEventHash(event)) return false
    if (typeof event.content !== 'string') return false
    if (typeof event.created_at !== 'number') return false

    if (!Array.isArray(event.tags)) return false
    for (let i = 0; i < event.tags.length; i++) {
        let tag = event.tags[i]
        if (!Array.isArray(tag)) return false
        for (let j = 0; j < tag.length; j++) {
            if (typeof tag[j] === 'object') return false
        }
    }

    return true
}

function verifySignature(event) {
    return secp256k1.schnorr.verify(event.sig, event.id, event.pubkey)
}


module.exports = {
    generatePrivateKey,
    getPublicKey,
    signEvent,
    validateEvent,
    verifySignature,
}