using System.Text;
using NSubstitute;
using Schaad.Accounting.Interfaces;
using Schaad.Accounting.Models;
using Schaad.Accounting.Services;
using Schaad.Finance.Api;
using Shouldly;

namespace Schaad.Accounting.Tests;

public class FileServiceTestShould
{
    private readonly ISettingsService settingsService = Substitute.For<ISettingsService>();
    private readonly IAccountRepository accountRepo = Substitute.For<IAccountRepository>();
    private readonly ITransactionRepository transactionRepo = Substitute.For<ITransactionRepository>();
    private readonly IBankTransactionRepository bankTransactionRepo = Substitute.For<IBankTransactionRepository>();
    private readonly IAccountStatementService accountStatementService = Substitute.For<IAccountStatementService>();
    private readonly ICreditCardStatementService creditCardStatementService = Substitute.For<ICreditCardStatementService>();

    public FileServiceTestShould()
    {
        // Registering the ISO-8859-1 code page provider so the CSV encoding call works
        // in the test host (which does not include legacy encodings by default).
        Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
    }

    private FileService BuildService() => new(
        settingsService, accountRepo, transactionRepo, bankTransactionRepo,
        accountStatementService, creditCardStatementService);

    [Fact]
    public void EmitHeaderRowAndRunningBalanceWhenExportingTransactionsCsv()
    {
        var checking = new Account { Id = "chk", Number = 1010, Name = "Checking", Currency = "CHF", StartBalance = 1000m };
        var groceries = new Account { Id = "groc", Number = 4200, Name = "Groceries", Currency = "CHF" };
        var salary = new Account { Id = "sal", Number = 3000, Name = "Salary", Currency = "CHF" };
        accountRepo.GetAccount("chk").Returns(checking);
        transactionRepo.GetTransactionList().Returns(new List<Transaction>
        {
            new()
            {
                Id = "t1", OriginAccountId = "chk", TargetAccountId = "groc", Value = 50m, Text = "Coop",
                BookingDate = new DateTime(2026, 1, 5), ValueDate = new DateTime(2026, 1, 5)
            },
            new()
            {
                Id = "t2", OriginAccountId = "sal", TargetAccountId = "chk", Value = 5000m, Text = "Salary",
                BookingDate = new DateTime(2026, 1, 25), ValueDate = new DateTime(2026, 1, 25)
            }
        });

        var bytes = BuildService().GetTransactionListCsv("chk");
        var csv = Encoding.GetEncoding("ISO-8859-1").GetString(bytes);
        var lines = csv.Split(Environment.NewLine, StringSplitOptions.RemoveEmptyEntries);

        lines[0].ShouldBe("Buchungsdatum;Valuta;Buchungstext;Belastung;Gutschrift;Saldo CHF");
        lines[1].ShouldBe(";;Startsaldo;;;1000");
        // Debit line (outgoing) — value in Belastung column, balance drops
        lines[2].ShouldBe("05.01.2026;05.01.2026;Coop;50.00;;950.00");
        // Credit line (incoming) — value in Gutschrift column, balance rises
        lines[3].ShouldBe("25.01.2026;25.01.2026;Salary;;5'000.00;5'950.00");
    }

    [Fact]
    public void OrderTransactionsByBookingDateThenValueDateThenValueWhenExporting()
    {
        var checking = new Account { Id = "chk", Number = 1010, Name = "Checking", Currency = "CHF", StartBalance = 0m };
        accountRepo.GetAccount("chk").Returns(checking);
        transactionRepo.GetTransactionList().Returns(new List<Transaction>
        {
            // Deliberately unordered
            new() { OriginAccountId = "chk", TargetAccountId = "x", Value = 10m, Text = "later",
                    BookingDate = new DateTime(2026, 2, 1), ValueDate = new DateTime(2026, 2, 1) },
            new() { OriginAccountId = "chk", TargetAccountId = "x", Value = 5m, Text = "earlier small",
                    BookingDate = new DateTime(2026, 1, 15), ValueDate = new DateTime(2026, 1, 15) },
            new() { OriginAccountId = "chk", TargetAccountId = "x", Value = 20m, Text = "earlier large",
                    BookingDate = new DateTime(2026, 1, 15), ValueDate = new DateTime(2026, 1, 15) }
        });

        var csv = Encoding.GetEncoding("ISO-8859-1").GetString(BuildService().GetTransactionListCsv("chk"));
        var lines = csv.Split(Environment.NewLine, StringSplitOptions.RemoveEmptyEntries);

        // Skip header + start balance rows
        lines[2].ShouldContain("earlier small");
        lines[3].ShouldContain("earlier large");
        lines[4].ShouldContain("later");
    }

    [Fact]
    public void NotMutateTransactionValueWhenExportingCsv()
    {
        var checking = new Account { Id = "chk", Number = 1010, Name = "Checking", Currency = "CHF" };
        accountRepo.GetAccount("chk").Returns(checking);
        var outgoing = new Transaction
        {
            OriginAccountId = "chk", TargetAccountId = "x", Value = 42m, Text = "test",
            BookingDate = new DateTime(2026, 1, 1), ValueDate = new DateTime(2026, 1, 1)
        };
        transactionRepo.GetTransactionList().Returns(new List<Transaction> { outgoing });

        BuildService().GetTransactionListCsv("chk");

        // Regression: earlier code did `trx.Value *= -1` mid-loop.
        outgoing.Value.ShouldBe(42m);
    }
}