using System;
using System.Diagnostics.CodeAnalysis;
using PaperlessAI.Models;

namespace PaperlessAI.Services;

public class DocumentProcessingService(ILogger<DocumentProcessingService> logger)
{
    private Queue<PaperlessDocument> paperlessDocumentsQueue = new Queue<PaperlessDocument>();
    private bool isWorking = false;

    public void Enqueue(List<PaperlessDocument> paperlessDocuments)
    {
        if(paperlessDocumentsQueue.Count != 0)
            return;

        foreach(var doc in paperlessDocuments)
        {
            Enqueue(doc);
        }
    }

    public void Enqueue(PaperlessDocument paperlessDocument)
    {
        if(paperlessDocumentsQueue.Contains(paperlessDocument, new PaperlessDocumentSameDocument()))
            return;

        paperlessDocumentsQueue.Enqueue(paperlessDocument);

        logger.LogInformation($"Enqueued document: {paperlessDocument}");
    }

    public void Process()
    {
        if(isWorking)
            return;

        if(paperlessDocumentsQueue.Count == 0)
            return;

        if(paperlessDocumentsQueue.TryDequeue(out PaperlessDocument? docToProcess))
        {
            logger.LogInformation($"Dequeued: {docToProcess}");
            ProcessDocument(docToProcess);
        }
    }

    private void ProcessDocument(PaperlessDocument docToProcess)
    {
        logger.LogInformation($"Processing: {docToProcess}");
        isWorking = true;
        
        isWorking = false;
    }
}

class PaperlessDocumentSameDocument : EqualityComparer<PaperlessDocument>
{
    public override bool Equals(PaperlessDocument? x, PaperlessDocument? y)
    {
        if (x == null && y == null)
            return true;
        else if (x == null || y == null)
            return false;

        return x.Id == y.Id || x.DocumentId == y.DocumentId;
    }

    public override int GetHashCode([DisallowNull] PaperlessDocument obj)
    {
        var hcode = obj.Id + obj.DocumentId;
        return hcode.GetHashCode();
    }
}