using Microsoft.EntityFrameworkCore;
using MoneyMap.Data;
using MoneyMap.Models;

namespace MoneyMap.Services;

/// <summary>
/// Service for core transaction operations including duplicate detection,
/// retrieval, and deletion.
/// </summary>
public interface ITransactionService
{
    /// <summary>
    /// Checks if a transaction is a duplicate based on date, amount, name, memo,
    /// account, and card.
    /// </summary>
    Task<bool> IsDuplicateAsync(Transaction transaction);

    /// <summary>
    /// Gets a transaction by ID with optional related data.
    /// </summary>
    Task<Transaction?> GetTransactionByIdAsync(long id, bool includeRelated = false);

    /// <summary>
    /// Deletes a transaction and all related data (receipts, parse logs, line items).
    /// </summary>
    Task<bool> DeleteTransactionAsync(long id);
}

public class TransactionService : ITransactionService
{
    private readonly MoneyMapContext _db;

    public TransactionService(MoneyMapContext db)
    {
        _db = db;
    }

    public async Task<bool> IsDuplicateAsync(Transaction transaction)
    {
        return await _db.Transactions.AnyAsync(t =>
            t.Date == transaction.Date &&
            t.Amount == transaction.Amount &&
            t.Name == transaction.Name &&
            t.Memo == transaction.Memo &&
            t.AccountId == transaction.AccountId &&
            t.CardId == transaction.CardId);
    }

    public async Task<Transaction?> GetTransactionByIdAsync(long id, bool includeRelated = false)
    {
        var query = _db.Transactions.AsQueryable();

        if (includeRelated)
        {
            query = query
                .Include(t => t.Card)
                    .ThenInclude(c => c!.Account)
                .Include(t => t.Account)
                .Include(t => t.TransferToAccount)
                .Include(t => t.Merchant)
                .Include(t => t.Receipts)
                    .ThenInclude(r => r.LineItems);
        }

        return await query.FirstOrDefaultAsync(t => t.Id == id);
    }

    public async Task<bool> DeleteTransactionAsync(long id)
    {
        var transaction = await _db.Transactions.FindAsync(id);
        if (transaction == null)
            return false;

        _db.Transactions.Remove(transaction);
        await _db.SaveChangesAsync();
        return true;
    }
}