PKHeX/PKHeX.Core/Legality/Tables/FormChangeUtil.cs
Kurt 9166d0eb64
Refactoring: Move Source (Legality) (#3560)
Rewrites a good amount of legality APIs pertaining to:
* Legal moves that can be learned
* Evolution chains & cross-generation paths
* Memory validation with forgotten moves

In generation 8, there are 3 separate contexts an entity can exist in: SW/SH, BD/SP, and LA. Not every entity can cross between them, and not every entity from generation 7 can exist in generation 8 (Gogoat, etc). By creating class models representing the restrictions to cross each boundary, we are able to better track and validate data.

The old implementation of validating moves was greedy: it would iterate for all generations and evolutions, and build a full list of every move that can be learned, storing it on the heap. Now, we check one game group at a time to see if the entity can learn a move that hasn't yet been validated. End result is an algorithm that requires 0 allocation, and a smaller/quicker search space.

The old implementation of storing move parses was inefficient; for each move that was parsed, a new object is created and adjusted depending on the parse. Now, move parse results are `struct` and store the move parse contiguously in memory. End result is faster parsing and 0 memory allocation.

* `PersonalTable` objects have been improved with new API methods to check if a species+form can exist in the game.
* `IEncounterTemplate` objects have been improved to indicate the `EntityContext` they originate in (similar to `Generation`).
* Some APIs have been extended to accept `Span<T>` instead of Array/IEnumerable
2022-08-03 16:15:27 -07:00

50 lines
1.9 KiB
C#

using System;
using System.Collections.Generic;
namespace PKHeX.Core;
public static class FormChangeUtil
{
public static bool ShouldIterateForms(ushort species, byte form, int generation, LearnOption option)
{
if (option is not LearnOption.Current)
return FormChangeMoves.TryGetValue(species, out var func) && func((generation, form));
return IterateAllForms(species);
}
public static bool IterateAllForms(int species) => FormChangeMovesRetain.Contains(species);
/// <summary>
/// Species that can change between their forms and get access to form-specific moves.
/// </summary>
private static readonly HashSet<int> FormChangeMovesRetain = new()
{
(int)Species.Deoxys,
(int)Species.Giratina,
(int)Species.Shaymin,
(int)Species.Hoopa,
};
/// <summary>
/// Species that can change between their forms and get access to form-specific moves.
/// </summary>
private static readonly Dictionary<int, Func<(int Generation, int Form), bool>> FormChangeMoves = new()
{
{(int)Species.Deoxys, g => g.Generation >= 6},
{(int)Species.Giratina, g => g.Generation >= 6},
{(int)Species.Shaymin, g => g.Generation >= 6},
{(int)Species.Rotom, g => g.Generation >= 6},
{(int)Species.Hoopa, g => g.Generation >= 6},
{(int)Species.Tornadus, g => g.Generation >= 6},
{(int)Species.Thundurus,g => g.Generation >= 6},
{(int)Species.Landorus, g => g.Generation >= 6},
{(int)Species.Urshifu, g => g.Generation >= 8},
{(int)Species.Enamorus, g => g.Generation >= 8},
// Fuse
{(int)Species.Kyurem, g => g.Generation >= 6},
{(int)Species.Necrozma, g => g.Generation >= 8},
{(int)Species.Calyrex, g => g.Generation >= 8},
{(int)Species.Pikachu, g => g.Generation == 6},
};
}