using Microsoft.EntityFrameworkCore;
using ZB.MOM.WW.OtOpcUa.Configuration;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.ScriptList;

/// <summary>One row of the <c>/scripts</c> list: everything the list renders, and nothing else.</summary>
/// <param name="ScriptId">The script's logical id.</param>
/// <param name="Name">The authored display name.</param>
/// <param name="Language">The script language (e.g. <c>CSharp</c>).</param>
/// <param name="SourceHash">The source hash shown abbreviated on the row.</param>
public sealed record ScriptListRow(string ScriptId, string Name, string Language, string SourceHash);

/// <summary>
///     Queries behind the <c>/scripts</c> page. The list is a projection that leaves out
///     <c>SourceCode</c> (R04 P8): loading every script's full source to render names and hashes made
///     the page cost proportional to the total size of every script in the fleet. The source is fetched
///     on demand, for one script, when its "Source" dialog opens.
/// </summary>
public static class ScriptListQueries
{
    /// <summary>Loads the list rows, ordered by name, without any script's source.</summary>
    /// <param name="db">The config DB context.</param>
    /// <param name="ct">Cancellation token.</param>
    /// <returns>The list rows.</returns>
    public static Task<List<ScriptListRow>> LoadRowsAsync(OtOpcUaConfigDbContext db, CancellationToken ct = default) =>
        db.Scripts.AsNoTracking()
            .OrderBy(s => s.Name)
            .Select(s => new ScriptListRow(s.ScriptId, s.Name, s.Language, s.SourceHash))
            .ToListAsync(ct);

    /// <summary>Loads one script's source, or null when the script no longer exists.</summary>
    /// <param name="db">The config DB context.</param>
    /// <param name="scriptId">The script's logical id.</param>
    /// <param name="ct">Cancellation token.</param>
    /// <returns>The source code, or null.</returns>
    public static Task<string?> LoadSourceAsync(OtOpcUaConfigDbContext db, string scriptId, CancellationToken ct = default) =>
        db.Scripts.AsNoTracking()
            .Where(s => s.ScriptId == scriptId)
            .Select(s => (string?)s.SourceCode)
            .FirstOrDefaultAsync(ct);
}