/*
 * This file is part of the storage node for the Joystream project.
 * Copyright (C) 2019 Joystream Contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

'use strict'

const debug = require('debug')('joystream:runtime:base')

const { registerJoystreamTypes } = require('@joystream/types')
const { ApiPromise, WsProvider } = require('@polkadot/api')

const { IdentitiesApi } = require('@joystream/storage-runtime-api/identities')
const { BalancesApi } = require('@joystream/storage-runtime-api/balances')
const { WorkersApi } = require('@joystream/storage-runtime-api/workers')
const { AssetsApi } = require('@joystream/storage-runtime-api/assets')
const { DiscoveryApi } = require('@joystream/storage-runtime-api/discovery')
const AsyncLock = require('async-lock')
const { newExternallyControlledPromise } = require('@joystream/storage-utils/externalPromise')

/*
 * Initialize runtime (substrate) API and keyring.
 */
class RuntimeApi {
	static async create(options) {
		const runtime_api = new RuntimeApi()
		await runtime_api.init(options || {})
		return runtime_api
	}

	async init(options) {
		debug('Init')

		options = options || {}

		// Register joystream types
		registerJoystreamTypes()

		const provider = new WsProvider(options.provider_url || 'ws://localhost:9944')

		// Create the API instrance
		this.api = await ApiPromise.create({ provider })

		this.asyncLock = new AsyncLock()

		// Keep track locally of account nonces.
		this.nonces = {}

		// The storage provider id to use
		this.storageProviderId = parseInt(options.storageProviderId) // u64 instead ?

		// Ok, create individual APIs
		this.identities = await IdentitiesApi.create(this, {
			account_file: options.account_file,
			passphrase: options.passphrase,
			canPromptForPassphrase: options.canPromptForPassphrase,
		})
		this.balances = await BalancesApi.create(this)
		this.workers = await WorkersApi.create(this)
		this.assets = await AssetsApi.create(this)
		this.discovery = await DiscoveryApi.create(this)
	}

	disconnect() {
		this.api.disconnect()
	}

	executeWithAccountLock(account_id, func) {
		return this.asyncLock.acquire(`${account_id}`, func)
	}

	/*
	 * Wait for an event. Filters out any events that don't match the module and
	 * event name.
	 *
	 * The result of the Promise is an array containing first the full event
	 * name, and then the event fields as an object.
	 */
	async waitForEvent(module, name) {
		return this.waitForEvents([[module, name]])
	}

	_matchingEvents(subscribed, events) {
		debug(`Number of events: ${events.length} subscribed to ${subscribed}`)

		const filtered = events.filter((record) => {
			const { event, phase } = record

			// Show what we are busy with
			debug(`\t${event.section}:${event.method}:: (phase=${phase.toString()})`)
			debug(`\t\t${event.meta.documentation.toString()}`)

			// Skip events we're not interested in.
			const matching = subscribed.filter((value) => {
				return event.section === value[0] && event.method === value[1]
			})
			return matching.length > 0
		})
		debug(`Filtered: ${filtered.length}`)

		const mapped = filtered.map((record) => {
			const { event } = record
			const types = event.typeDef

			// Loop through each of the parameters, displaying the type and data
			const payload = {}
			event.data.forEach((data, index) => {
				debug(`\t\t\t${types[index].type}: ${data.toString()}`)
				payload[types[index].type] = data
			})

			const full_name = `${event.section}.${event.method}`
			return [full_name, payload]
		})
		debug('Mapped', mapped)

		return mapped
	}

	/*
	 * Same as waitForEvent, but filter on multiple events. The parameter is an
	 * array of arrays containing module and name. Calling waitForEvent is
	 * identical to calling this with [[module, name]].
	 *
	 * Returns the first matched event *only*.
	 */
	async waitForEvents(subscribed) {
		return new Promise((resolve, reject) => {
			this.api.query.system.events((events) => {
				const matches = this._matchingEvents(subscribed, events)
				if (matches && matches.length) {
					resolve(matches)
				}
			})
		})
	}

	/*
	 * Nonce-aware signAndSend(). Also allows you to use the accountId instead
	 * of the key, making calls a little simpler. Will lock to prevent concurrent
	 * calls so correct nonce is used.
	 *
	 * If the subscribed events are given, and a callback as well, then the
	 * callback is invoked with matching events.
	 */
	async signAndSend(accountId, tx, attempts, subscribed, callback) {
		accountId = this.identities.keyring.encodeAddress(accountId)

		// Key must be unlocked
		const from_key = this.identities.keyring.getPair(accountId)
		if (from_key.isLocked) {
			throw new Error('Must unlock key before using it to sign!')
		}

		const finalizedPromise = newExternallyControlledPromise()

		const unsubscribe = await this.executeWithAccountLock(accountId, async () => {
			// Try to get the next nonce to use
			let nonce = this.nonces[accountId]

			let incrementNonce = () => {
				// only increment once
				incrementNonce = () => {} // turn it into a no-op
				nonce = nonce.addn(1)
				this.nonces[accountId] = nonce
			}

			// If the nonce isn't available, get it from chain.
			if (!nonce) {
				// current nonce
				nonce = await this.api.query.system.accountNonce(accountId)
				debug(`Got nonce for ${accountId} from chain: ${nonce}`)
			}

			return new Promise((resolve, reject) => {
				debug('Signing and sending tx')
				// send(statusUpdates) returns a function for unsubscribing from status updates
				const unsubscribe = tx
					.sign(from_key, { nonce })
					.send(({ events = [], status }) => {
						debug(`TX status: ${status.type}`)

						// Whatever events we get, process them if there's someone interested.
						// It is critical that this event handling doesn't prevent
						try {
							if (subscribed && callback) {
								const matched = this._matchingEvents(subscribed, events)
								debug('Matching events:', matched)
								if (matched.length) {
									callback(matched)
								}
							}
						} catch (err) {
							debug(`Error handling events ${err.stack}`)
						}

						// We want to release lock as early as possible, sometimes Ready status
						// doesn't occur, so we do it on Broadcast instead
						if (status.isReady) {
							debug('TX Ready.')
							incrementNonce()
							resolve(unsubscribe) // releases lock
						} else if (status.isBroadcast) {
							debug('TX Broadcast.')
							incrementNonce()
							resolve(unsubscribe) // releases lock
						} else if (status.isFinalized) {
							debug('TX Finalized.')
							finalizedPromise.resolve(status)
						} else if (status.isFuture) {
							// comes before ready.
							// does that mean it will remain in mempool or in api internal queue?
							// nonce was set in the future. Treating it as an error for now.
							debug('TX Future!')
							// nonce is likely out of sync, delete it so we reload it from chain on next attempt
							delete this.nonces[accountId]
							const err = new Error('transaction nonce set in future')
							finalizedPromise.reject(err)
							reject(err)
						}

						/* why don't we see these status updates on local devchain (single node)
            isUsurped
            isBroadcast
            isDropped
            isInvalid
            */
					})
					.catch((err) => {
						// 1014 error: Most likely you are sending transaction with the same nonce,
						// so it assumes you want to replace existing one, but the priority is too low to replace it (priority = fee = len(encoded_transaction) currently)
						// Remember this can also happen if in the past we sent a tx with a future nonce, and the current nonce
						// now matches it.
						if (err) {
							const errstr = err.toString()
							// not the best way to check error code.
							// https://github.com/polkadot-js/api/blob/master/packages/rpc-provider/src/coder/index.ts#L52
							if (
								errstr.indexOf('Error: 1014:') < 0 && // low priority
								errstr.indexOf('Error: 1010:') < 0
							) {
								// bad transaction
								// Error but not nonce related. (bad arguments maybe)
								debug('TX error', err)
							} else {
								// nonce is likely out of sync, delete it so we reload it from chain on next attempt
								delete this.nonces[accountId]
							}
						}

						finalizedPromise.reject(err)
						// releases lock
						reject(err)
					})
			})
		})

		// when does it make sense to manyally unsubscribe?
		// at this point unsubscribe.then and unsubscribe.catch have been deleted
		// unsubscribe() // don't unsubscribe if we want to wait for additional status
		// updates to know when the tx has been finalized
		return finalizedPromise.promise
	}

	/*
	 * Sign and send a transaction expect event from
	 * module and return eventProperty from the event.
	 */
	async signAndSendThenGetEventResult(senderAccountId, tx, { eventModule, eventName, eventProperty }) {
		// event from a module,
		const subscribed = [[eventModule, eventName]]
		return new Promise(async (resolve, reject) => {
			try {
				await this.signAndSend(senderAccountId, tx, 1, subscribed, (events) => {
					events.forEach((event) => {
						// fix - we may not necessarily want the first event
						// if there are multiple events emitted,
						resolve(event[1][eventProperty])
					})
				})
			} catch (err) {
				reject(err)
			}
		})
	}
}

module.exports = {
	RuntimeApi,
}