import { promisify } from 'util';
import { finished } from 'stream';
import { once } from 'events';
import fs from 'fs';
import readline from 'readline';
// locals
import { binSize, getPrefix } from './util';
import { optimizePrefixSize } from './optimizePrefixSize';
const streamFinished = promisify(finished); // (A)
export async function makeIxx(inIx, outIxx, prefixSizeParam) {
    const out = fs.createWriteStream(outIxx);
    const prefixSize = prefixSizeParam !== null && prefixSizeParam !== void 0 ? prefixSizeParam : (await optimizePrefixSize(inIx));
    try {
        const fileStream = fs.createReadStream(inIx);
        const rl = readline.createInterface({
            input: fileStream,
        });
        let lastPrefix;
        let writtenPrefix;
        let writtenPos = -binSize;
        let startPrefixPos = 0;
        let bytes = 0;
        for await (const line of rl) {
            const [word] = line.split(/\s/);
            const curPrefix = getPrefix(word, prefixSize);
            if (curPrefix !== lastPrefix) {
                startPrefixPos = bytes;
            }
            if (bytes - writtenPos >= binSize && curPrefix !== writtenPrefix) {
                const res = out.write(`${curPrefix}${startPrefixPos
                    .toString(16)
                    .toUpperCase()
                    .padStart(10, '0')}\n`);
                // Handle backpressure
                // ref https://nodesource.com/blog/understanding-streams-in-nodejs/
                if (!res) {
                    await once(out, 'drain');
                }
                writtenPos = bytes;
                writtenPrefix = curPrefix;
            }
            lastPrefix = curPrefix;
            bytes += line.length + 1;
        }
    }
    finally {
        out.end();
        await streamFinished(out);
    }
}
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