using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}

​

// I wrote

public class PostgrsDBRepository : IRepository {

​

}

​

// Prompt on the blank like was

// Make a postgres repository to store entries using json, and include scaffolding

​

// Output:

public class PostgresDBRepository : IRepository

{

    private readonly string _connectionString;

​

    public PostgresDBRepository(string connectionString)

    {

        _connectionString = connectionString;

        SetupDatabase();

    }

​

    private void SetupDatabase()

    {

        using var connection = new NpgsqlConnection(_connectionString);

        connection.Open();

​

        using var command = new NpgsqlCommand(

            @"CREATE TABLE IF NOT EXISTS repositories (

                id SERIAL PRIMARY KEY,

                name TEXT NOT NULL,

                key TEXT NOT NULL,

                value JSONB NOT NULL

            )", connection);

​

        command.ExecuteNonQuery();

    }

​

    public async Task<T?> Get<T>(string repoName, string key, CancellationToken cancellationToken, string? fileType = null)

    {

        fileType ??= "json";

​

        using var connection = new NpgsqlConnection(_connectionString);

        connection.Open();

​

        using var command = new NpgsqlCommand(

            @"SELECT value FROM repositories WHERE name = @name AND key = @key",

            connection);

​

        command.Parameters.AddWithValue("@name", repoName);

        command.Parameters.AddWithValue("@key", key);

​

        await using var reader = await command.ExecuteReaderAsync(cancellationToken);

​

        if (!reader.HasRows)

        {

            return default;

        }

​

        await reader.ReadAsync(cancellationToken);

​

        var json = reader.GetString(0);

​

        return JsonSerializer.Deserialize<T>(json);

    }

​

    public async Task Set<T>(string repoName, string key, T value, CancellationToken cancellationToken, string? fileType = null)

    {

        fileType ??= "json";

​

        var json = JsonSerializer.Serialize(value);

​

        using var connection = new NpgsqlConnection(_connectionString);

        connection.Open();

​

        using var command = new NpgsqlCommand(

            @"INSERT INTO repositories (name, key, value) VALUES (@name, @key, @value)

            ON CONFLICT (name, key) DO UPDATE SET value = @value",

            connection);

​

        command.Parameters.AddWithValue("@name", repoName);

        command.Parameters.AddWithValue("@key", key);

        command.Parameters.AddWithValue("@value", json);

​

        await command.ExecuteNonQueryAsync(cancellationToken);

    }

​

    public async Task Remove(string repoName, string key, CancellationToken cancellationToken, string? fileType = null)

    {

        fileType ??= "json";

​

        using var connection = new NpgsqlConnection(_connectionString);

        connection.Open();

​

        using var command = new NpgsqlCommand(

            @"DELETE FROM repositories WHERE name = @name AND key = @key",

            connection);

​

        command.Parameters.AddWithValue("@name", repoName);

        command.Parameters.AddWithValue("@key", key);

​

        await command.ExecuteNonQueryAsync(cancellationToken);

    }

}

​