const fs = require('fs')
const { AzureKeyCredential, DocumentAnalysisClient } = require("@azure/ai-form-recognizer");

function* getTextOfSpans(content, spans) {
    for (const span of spans) {
        yield content.slice(span.offset, span.offset + span.length);
    }
}

const endpoint = "";
const key = "";

// sample document
const formUrl = "https://raw.githubusercontent.com/Azure-Samples/cognitive-services-REST-api-samples/master/curl/form-recognizer/rest-api/read.png"

async function main() {
    // create your `DocumentAnalysisClient` instance and `AzureKeyCredential` variable
    const client = new DocumentAnalysisClient(endpoint, new AzureKeyCredential(key));
    const poller = await client.beginAnalyzeDocument("prebuilt-read", formUrl);

    const { content, pages, languages, styles } = await poller.pollUntilDone();

    if (pages.length <= 0) {
        console.log("No pages were extracted from the document.");
    } else {
        console.log("Pages:");
        for (const page of pages) {
            console.log("- Page", page.pageNumber, `(unit: ${page.unit})`);
            console.log(`  ${page.width}x${page.height}, angle: ${page.angle}`);
            console.log(`  ${page.lines.length} lines, ${page.words.length} words`);

            if (page.lines.length > 0) {
                // console.log("  Lines:");

                for (const line of page.lines) {
                    console.log(`  - "${line.content}"`);
                    const data = line.content;
                    fs.writeFile('file.txt', data, { flag: 'a+' }, (err) => {
                        if (err) {
                            throw err;
                        }
                        console.log("File is updated.");
                    });

                    // The words of the line can also be iterated independently. The words are computed based on their
                    // corresponding spans.
                    for (const word of line.words()) {
                        console.log(`    - "${word.content}"`);
                    }
                }
            }
        }
    }

    if (languages.length <= 0) {
        console.log("No language spans were extracted from the document.");
    } else {
        console.log("Languages:");
        for (const languageEntry of languages) {
            console.log(
                `- Found language: ${languageEntry.languageCode} (confidence: ${languageEntry.confidence})`
            );
            for (const text of getTextOfSpans(content, languageEntry.spans)) {
                const escapedText = text.replace(/\r?\n/g, "\\n").replace(/"/g, '\\"');
                console.log(`  - "${escapedText}"`);
            }
        }
    }

    if (styles.length <= 0) {
        console.log("No text styles were extracted from the document.");
    } else {
        console.log("Styles:");
        for (const style of styles) {
            console.log(
                `- Handwritten: ${style.isHandwritten ? "yes" : "no"} (confidence=${style.confidence})`
            );

            for (const word of getTextOfSpans(content, style.spans)) {
                console.log(`  - "${word}"`);
            }
        }
    }
}

main().catch((error) => {
    console.error("An error occurred:", error);
    process.exit(1);
});