using Microsoft.AspNetCore.Mvc.Rendering;
using PowderCoating.Core.Enums;
using PowderCoating.Core.Interfaces;
using PowderCoating.Shared.Constants;

namespace PowderCoating.Web.Helpers;

/// <summary>
/// Centralizes the repeated DB queries and SelectListItem projections used by the accounting
/// controllers (Bills, Expenses). Each controller assigns only the properties it needs to ViewBag,
/// so the naming mismatch between controllers (BankAccounts vs PaymentAccounts) is harmless.
/// </summary>
internal static class AccountingDropdownHelper
{
    /// <summary>
    /// Loads vendors, accounts, payment methods, and active jobs in a single call.
    /// Returns pre-projected SelectListItem collections so controllers avoid duplicating the
    /// LINQ-to-SelectListItem transform.
    /// </summary>
    internal static async Task<AccountingDropdowns> LoadAsync(IUnitOfWork unitOfWork)
    {
        var vendors = await unitOfWork.Vendors.FindAsync(v => v.IsActive);
        var allAccounts = await unitOfWork.Accounts.FindAsync(a => a.IsActive);
        var jobs = await unitOfWork.Jobs.FindAsync(j =>
            j.JobStatus.StatusCode != AppConstants.StatusCodes.Job.Completed &&
            j.JobStatus.StatusCode != AppConstants.StatusCodes.Job.Cancelled &&
            j.JobStatus.StatusCode != AppConstants.StatusCodes.Job.Delivered);

        var accountLabel = (Core.Entities.Account a) => $"{a.AccountNumber} – {a.Name}";

        return new AccountingDropdowns
        {
            Vendors = vendors
                .OrderBy(v => v.CompanyName)
                .Select(v => new SelectListItem(v.CompanyName, v.Id.ToString()))
                .ToList(),

            ExpenseAccounts = allAccounts
                .Where(a => a.AccountType == AccountType.Expense ||
                            a.AccountType == AccountType.CostOfGoods)
                .OrderBy(a => a.AccountNumber)
                .Select(a => new SelectListItem(accountLabel(a), a.Id.ToString()))
                .ToList(),

            ExpenseAndAssetAccounts = allAccounts
                .Where(a => a.AccountType == AccountType.Expense ||
                            a.AccountType == AccountType.CostOfGoods ||
                            a.AccountType == AccountType.Asset)
                .OrderBy(a => a.AccountNumber)
                .Select(a => new SelectListItem(accountLabel(a), a.Id.ToString()))
                .ToList(),

            ApAccounts = allAccounts
                .Where(a => a.AccountSubType == AccountSubType.AccountsPayable)
                .OrderBy(a => a.AccountNumber)
                .Select(a => new SelectListItem(accountLabel(a), a.Id.ToString()))
                .ToList(),

            BankAccounts = allAccounts
                .Where(a => a.AccountSubType == AccountSubType.Cash ||
                            a.AccountSubType == AccountSubType.Checking ||
                            a.AccountSubType == AccountSubType.Savings ||
                            a.AccountSubType == AccountSubType.CreditCard)
                .OrderBy(a => a.AccountNumber)
                .Select(a => new SelectListItem(accountLabel(a), a.Id.ToString()))
                .ToList(),

            PaymentMethods = Enum.GetValues<PaymentMethod>()
                .Select(m => new SelectListItem(m.ToString(), ((int)m).ToString()))
                .ToList(),

            ActiveJobs = jobs
                .OrderBy(j => j.JobNumber)
                .Select(j => new SelectListItem(
                    $"{j.JobNumber} – {j.Description ?? "No description"}",
                    j.Id.ToString()))
                .ToList()
        };
    }
}

internal sealed class AccountingDropdowns
{
    public IReadOnlyList<SelectListItem> Vendors { get; init; } = [];

    /// <summary>Expense + Cost of Goods accounts (used by Expenses controller).</summary>
    public IReadOnlyList<SelectListItem> ExpenseAccounts { get; init; } = [];

    /// <summary>Expense + Cost of Goods + Asset accounts (used by Bills controller).</summary>
    public IReadOnlyList<SelectListItem> ExpenseAndAssetAccounts { get; init; } = [];

    /// <summary>Accounts Payable accounts (used by Bills controller).</summary>
    public IReadOnlyList<SelectListItem> ApAccounts { get; init; } = [];

    /// <summary>Cash, Checking, Savings, and Credit Card accounts.</summary>
    public IReadOnlyList<SelectListItem> BankAccounts { get; init; } = [];

    public IReadOnlyList<SelectListItem> PaymentMethods { get; init; } = [];
    public IReadOnlyList<SelectListItem> ActiveJobs { get; init; } = [];
}