Split and Combine Batch ID800

// This single node replaces 'Split Batch Manually' and 'Combine Data'.
// It's robust and solves the "lost data" problem.

// 1. Get the single item output from the LLM node.
const llmOutputItem = $input.item;
let analysisResultsArray;

// 2. Safely parse the LLM output. The LangChain node can be inconsistent;
// sometimes it returns a parsed object, other times a raw text string.
// This code handles both possibilities gracefully.
if (llmOutputItem.json.analysisResults) {
    // Case 1: The output is already a parsed object.
    analysisResultsArray = llmOutputItem.json.analysisResults;
} else if (llmOutputItem.json.text) {
    // Case 2: The output is a string that needs to be parsed.
    try {
        analysisResultsArray = JSON.parse(llmOutputItem.json.text).analysisResults;
    } catch (e) {
        throw new Error(`Failed to parse JSON from the LLM's text output. Error: ${e.message}`);
    }
}

// 3. If we still don't have a valid array, we cannot proceed. Throw a clear error.
if (!Array.isArray(analysisResultsArray)) {
    throw new Error(`Could not find or parse the 'analysisResults' array from the LLM output. Received data: ${JSON.stringify(llmOutputItem.json)}`);
}

// 4. Get the original batch data from the 'Generate Batch Prompt' node.
// This is the key step that solves the problem of the lost data.
const originalBatch = $('Generate Batch Prompt').first().json.fileBatch;

// 5. Loop through each analysis result and merge it with its corresponding original data.
const finalMergedItems = analysisResultsArray.map(llmResult => {
    // Find the corresponding original file using the full filePath as a unique key.
    const originalFileWrapper = originalBatch.find(f => f.originalItem.filePath === llmResult.filePath);

    if (!originalFileWrapper) {
        // This case handles if the LLM fails to return a matching filePath.
        // We return an item that clearly indicates a merge failure for later debugging.
        return { 
            json: {
                ...llmResult,
                chunkingStrategy: 'merge_failed',
                reasoning: `Combine Data: Could not find matching original file for path: ${llmResult.filePath}`
            }
        };
    }

    // Create the final, clean JSON object by combining the original data with the new analysis.
    const finalJson = {
        ...originalFileWrapper.originalItem,
        ...llmResult
    };

    return { json: finalJson };
});

// 6. Return the complete list of successfully merged items to the next node.
return finalMergedItems;