using System.IO;
using ErsatzTV.Core.Domain;

namespace ErsatzTV.Core.Graphics;

public static class GraphicsElementDefaults
{
    // Built-in "On Now / Next" text element filename -- a component of OnNowNextSeededPath below,
    // never itself an identity check (#568: a filename-only comparison is folder-agnostic).
    public const string OnNowNextFileName = "on-now-next.yml";

    // Display name only. Never use it for identity -- that is IsOnNowNext below (#67 / #74 / #568).
    public const string OnNowNextName = "On Now / Next";

    // The full path the seeder writes the built-in template to (GraphicsElementSeeder.SeedOnNowNext
    // builds `target` the same way). A `builtIn` discriminator must match THIS, not
    // `Path.GetFileName(...) == OnNowNextFileName` -- a filename-only comparison is folder-agnostic:
    // a user element named exactly `on-now-next.yml` in any of the other four template folders
    // (image/motion/subtitle/script) would also report `builtIn:true` (#568). `Kind == Text` alone
    // does not close this either, since a second text template could share the filename in principle.
    public static string OnNowNextSeededPath =>
        Path.Combine(FileSystemLayout.GraphicsElementsTextTemplatesFolder, OnNowNextFileName);

    /// <summary>
    ///     The one identity test for the built-in On Now / Next element: the exact file the seeder
    ///     wrote, at the exact path it wrote it to, of the kind it wrote it as. Ordinal on purpose,
    ///     and so case-sensitive on purpose.
    /// </summary>
    /// <remarks>
    ///     <para>
    ///         <c>Kind</c> is part of the identity rather than a second test any caller may add or
    ///         skip: the seeder's own "does the built-in row exist yet?" check resolves through this
    ///         predicate, so a row of another kind at the seeded path answering yes would suppress
    ///         the Text row every consumer resolves. A caller applying only the path half would
    ///         report that wrong-kind row as the built-in element while the seeder refused to treat
    ///         it as one -- the two sites disagreeing about the same row, which is the defect this
    ///         predicate exists to make impossible (#568).
    ///     </para>
    ///     <para>
    ///         Callers compare in memory rather than in a <c>Where</c> clause, because in SQL the
    ///         answer would be the PROVIDER's to give: <c>GraphicsElement.Path</c> takes no explicit
    ///         collation (<c>TvContext.OnModelCreating</c> pins one only on the listed name/title
    ///         columns), so SQLite compares it case-sensitively while MySQL uses the server default,
    ///         which is normally case-INsensitive. Evaluating one discriminator site in SQL and the
    ///         other in memory would let the two disagree on MySQL alone. The SQLite test suite
    ///         cannot tell the two apart -- BINARY collation and an ordinal comparison agree on
    ///         every input -- so this is held by keeping the comparison out of SQL, not by a test.
    ///     </para>
    /// </remarks>
    public static bool IsOnNowNext(string path, GraphicsElementKind kind) =>
        kind == GraphicsElementKind.Text && string.Equals(path, OnNowNextSeededPath, StringComparison.Ordinal);
}