import fs from "fs";
import {fetchSymbolsForSource} from "./service/exchange-service.js";
import {FormatterOptionsArgs, writeToStream, FormatterRow} from "fast-csv";
import log from "./service/log.js";
import {Classification} from "./interfaces.js";
import kleur from "kleur";


const write = (stream: NodeJS.WritableStream, rows: FormatterRow[], options: FormatterOptionsArgs<FormatterRow, FormatterRow>): Promise<void> => {
    return new Promise((res, rej) => {
        writeToStream(stream, rows, options)
            .on('error', (err: Error) => rej(err))
            .on('finish', () => res());
    });
}

export const fetchSymbolsMain = async (source: string, quoteAssetFilter?: string, classificationFilter?: string) => {

    const formattedExchange = source.toLowerCase()

    let baseSymbols = await fetchSymbolsForSource(formattedExchange)

    const breakdown = baseSymbols.reduce((acc, symbol) => {

        if (typeof acc[symbol.classification] !== "undefined") {
            acc[symbol.classification] += 1
        } else {
            acc[symbol.classification] = 1
        }
        return acc
    }, {})

    log.info("Parsed symbols classification breakdown:")

    for (const key of Object.keys(Classification)) {
        log.info(`    ${key}: ${breakdown[key] || 0 }`)
    }


    if (quoteAssetFilter) {
        baseSymbols = baseSymbols.filter((sym) => sym.quoteAsset.toLowerCase() === quoteAssetFilter.toLowerCase())
    }

    if (classificationFilter) {
        baseSymbols = baseSymbols.filter((sym) => sym.classification.toLowerCase() === classificationFilter.toLowerCase())
    }

    if (!baseSymbols || baseSymbols.length == 0) {
        throw new Error("No symbols fetched or match filters!")
    }


    const rows = baseSymbols.map((baseSymbol) => {
        return {
            symbol: baseSymbol.id,
            instrument: baseSymbol.instrument,
            quote_asset: baseSymbol.quoteAsset,
            alert_name: ""
        }
    })

    const outputPath = `${formattedExchange}${classificationFilter? "_" + classificationFilter.toLowerCase() : ""}${quoteAssetFilter? "_" + quoteAssetFilter.toLowerCase() : ""}_symbols.csv`;
    const outStream = fs.createWriteStream(outputPath)


    await write(outStream, rows, {headers: true})

    log.success(`Wrote ${rows.length} rows to: ${kleur.blue(outputPath)}`)
}