import {RestrictedSnapstate} from "@chasemoskal/snapstate"

import {currencyLibrary} from "./ecommerce/currency-library.js"
import {bankOfCanadaSupportedCurrencies} from "./currency-tools/bank-of-canada/supported-currencies.js"

export type BankOfCanadaSupportedCurrencies =
	typeof bankOfCanadaSupportedCurrencies[number]

export type SupportedCurrency = keyof typeof currencyLibrary

export type SupportedCurrencies = SupportedCurrency[]

export interface DownloadExchangeRatesParams {
	currencies: string[]
}

export interface DownloadExchangeRatesResults {
	exchangeRates: CurrencyExchangeRates
}

export type DownloadExchangeRates = ({}: DownloadExchangeRatesParams) =>
	Promise<DownloadExchangeRatesResults>

export interface CurrencyExchangeRates {
	[key: string]: number
}

export interface ConvertCurrencyParams {
	value: number
	inputCurrency: string
	outputCurrency: string
	exchangeRates: CurrencyExchangeRates
}

export interface FormattableNumber {
	value: number
	precision?: number
	locale?: string
}

export interface CurrencyDetails {
	code: string   // "USD"
	name: string   // United States Dollar
	symbol: string // "$"
}

export interface Money {
	currency: CurrencyDetails
	value: number  // 1234.56
	amount: string // "1,234.56"
	price: string  // "$1,234.56 USD"
}

export interface CurrencyLibrary {
	[code: string]: CurrencyDetails
}

export interface FormatCurrencyParams extends FormattableNumber {
	code: string
	currencyLibrary?: CurrencyLibrary
}

export interface ConvertAndFormatCurrencyParams extends FormattableNumber {
	inputCurrency: string
	outputCurrency: string
	exchangeRates: CurrencyExchangeRates
}

export interface CurrenciesByLocales {
	[locale: string]: string
}

export interface AssumeUserCurrencyParams {
	fallback: string
	currencies: string[]
	locale?: string
	currenciesByLocales?: CurrenciesByLocales
}

export interface AscertainEcommerceDetailsParams extends DownloadExchangeRatesParams {
	storeBaseCurrency: string
	userDisplayCurrency: string
	cacheLifespan?: number
	cacheStorageKey?: string
	cacheStorage?: BasicStorage
}

export interface EcommerceDetails {
	storeBaseCurrency: string
	userDisplayCurrency: string
	exchangeRates: CurrencyExchangeRates
}

export interface BasicStorage {
	getItem(key: string): string
	setItem(key: string, value: string): void
	removeItem(key: string): void
}

export interface JsonStorage {
	getItem<T>(key: string): undefined | T
	setItem<T>(key: string, value: T): void
	removeItem(key: string): void
}

export interface ConverterPersistence {
	cacheLifespan: number
	storage: BasicStorage
	storageKeys: {
		currencyPreference: string
		exchangeRatesCache: string
	}
}

export interface ListenForStorageChange {
	({}: {reloadCurrencyPreference: () => void}): void
}

export interface ConverterParams {
	baseCurrency: string
	currencies?: string[]
	locale?: string
	persistence?: ConverterPersistence
	downloadExchangeRates?: DownloadExchangeRates
	listenForStorageChange?: ListenForStorageChange
}

export interface ConverterDisplayOptions {
	currency?: string
	precision?: number
}

export interface CurrencyConverter {
	snap: RestrictedSnapstate<{
		currencyPreference: string
		exchangeRates: CurrencyExchangeRates
	}>
	readonly exchangeRatesDownload: Promise<void | CurrencyExchangeRates>
	readonly baseCurrency: string
	readonly currencyPreference: string
	readonly targetCurrency: string
	readonly availableCurrencies: CurrencyLibrary
	setCurrencyPreference(currency: string): void
	display(
		valueInBaseCurrency: number,
		options?: ConverterDisplayOptions,
	): Money
}