using System;
using System.IO;
using Migrato.Core;
using Xunit;

namespace Migrato.Tests;

public class MigrationParserTests : IDisposable
{
    private readonly string _tempDirectory = Directory.CreateTempSubdirectory("migrato-tests-").FullName;

    [Fact]
    public void Parse_ValidFile_ReturnsMigrationWithParsedSections()
    {
        var path = WriteFile(
            "20260101120000_create_users.sql",
            "-- +migrato Up\nCREATE TABLE users (id INTEGER PRIMARY KEY);\n\n-- +migrato Down\nDROP TABLE users;\n");

        var migration = MigrationParser.Parse(path);

        Assert.Equal(20260101120000L, migration.Version);
        Assert.Equal("create_users", migration.Name);
        Assert.Equal("CREATE TABLE users (id INTEGER PRIMARY KEY);", migration.UpSql);
        Assert.Equal("DROP TABLE users;", migration.DownSql);
        Assert.Equal(path, migration.Source);
    }

    [Fact]
    public void Parse_MarkersAreCaseInsensitive()
    {
        var path = WriteFile(
            "20260101120000_case_insensitive.sql",
            "-- +MIGRATO up\nSELECT 1;\n-- +migrato DOWN\nSELECT 2;\n");

        var migration = MigrationParser.Parse(path);

        Assert.Equal("SELECT 1;", migration.UpSql);
        Assert.Equal("SELECT 2;", migration.DownSql);
    }

    [Theory]
    [InlineData("not_a_migration.sql")]
    [InlineData("2026_bad_version.sql")]
    [InlineData("20260101120000.sql")]
    public void Parse_InvalidFileName_Throws(string fileName)
    {
        var path = WriteFile(fileName, "-- +migrato Up\nSELECT 1;\n-- +migrato Down\nSELECT 2;\n");

        Assert.Throws<MigrationFormatException>(() => MigrationParser.Parse(path));
    }

    [Fact]
    public void Parse_MissingUpMarker_Throws()
    {
        var path = WriteFile("20260101120000_missing_up.sql", "-- +migrato Down\nSELECT 2;\n");

        Assert.Throws<MigrationFormatException>(() => MigrationParser.Parse(path));
    }

    [Fact]
    public void Parse_MissingDownMarker_Throws()
    {
        var path = WriteFile("20260101120000_missing_down.sql", "-- +migrato Up\nSELECT 1;\n");

        Assert.Throws<MigrationFormatException>(() => MigrationParser.Parse(path));
    }

    [Fact]
    public void Parse_DownBeforeUp_Throws()
    {
        var path = WriteFile(
            "20260101120000_out_of_order.sql",
            "-- +migrato Down\nSELECT 2;\n-- +migrato Up\nSELECT 1;\n");

        Assert.Throws<MigrationFormatException>(() => MigrationParser.Parse(path));
    }

    [Fact]
    public void Parse_DuplicateMarker_Throws()
    {
        var path = WriteFile(
            "20260101120000_duplicate.sql",
            "-- +migrato Up\nSELECT 1;\n-- +migrato Up\nSELECT 2;\n-- +migrato Down\nSELECT 3;\n");

        Assert.Throws<MigrationFormatException>(() => MigrationParser.Parse(path));
    }

    private string WriteFile(string fileName, string content)
    {
        var path = Path.Combine(_tempDirectory, fileName);
        File.WriteAllText(path, content);
        return path;
    }

    public void Dispose()
    {
        Directory.Delete(_tempDirectory, recursive: true);
    }
}