using System.Data.Common;
using Microsoft.EntityFrameworkCore;

namespace MeterVault.Integration.Tests;

[Collection("Timescale")]
public sealed class SchemaTests(TimescaleFixture fx)
{
    [Fact]
    public async Task Migrations_are_applied()
    {
        await using var ctx = fx.CreateContext();
        var applied = (await ctx.Database.GetAppliedMigrationsAsync()).ToList();

        Assert.Contains(applied, m => m.EndsWith("InitialSchema", StringComparison.Ordinal));
        Assert.Contains(applied, m => m.EndsWith("TimescaleHypertables", StringComparison.Ordinal));
    }

    [Fact]
    public async Task Reading_and_consumption_are_hypertables()
    {
        await using var ctx = fx.CreateContext();
        var conn = ctx.Database.GetDbConnection();
        await conn.OpenAsync();

        var names = await QueryStringsAsync(conn,
            "SELECT hypertable_name FROM timescaledb_information.hypertables ORDER BY hypertable_name;");

        Assert.Equal(["consumption", "reading"], names);
    }

    [Fact]
    public async Task Reading_has_a_compression_policy()
    {
        await using var ctx = fx.CreateContext();
        var conn = ctx.Database.GetDbConnection();
        await conn.OpenAsync();

        // A compression/columnstore policy shows up as a scheduled job against the hypertable.
        var jobs = await QueryStringsAsync(conn,
            "SELECT hypertable_name FROM timescaledb_information.jobs " +
            "WHERE proc_name IN ('policy_compression', 'policy_columnstore') AND hypertable_name = 'reading';");

        Assert.Contains("reading", jobs);
    }

    private static async Task<List<string>> QueryStringsAsync(DbConnection conn, string sql)
    {
        await using var cmd = conn.CreateCommand();
        cmd.CommandText = sql;
        var results = new List<string>();
        await using var reader = await cmd.ExecuteReaderAsync();
        while (await reader.ReadAsync())
        {
            results.Add(reader.GetString(0));
        }

        return results;
    }
}