using System;
using System.Collections.Generic;

namespace WhiteMagic.Hooking;

/// <summary>
/// Manages named inline detours against a <see cref="MemoryBase"/>.
/// Detours only work when operating in-process; applying a detour to an
/// external target will fail because the hook delegate lives in the host process.
/// </summary>
public sealed class DetourManager
{
    private readonly MemoryBase _memory;
    private readonly Dictionary<string, Detour> _detours = new();

    /// <summary>Creates a detour manager bound to the supplied memory reader.</summary>
    public DetourManager(MemoryBase memory)
    {
        _memory = memory;
    }

    /// <summary>
    /// Creates a new detour and registers it with the manager.
    /// The <paramref name="hook"/> delegate's type must match the native signature of
    /// <paramref name="target"/>.
    /// </summary>
    public Detour Create(string name, IntPtr target, Delegate hook)
    {
        var detour = new Detour(_memory, name, target, hook);
        _detours[name] = detour;
        return detour;
    }

    /// <summary>Looks up a detour by name.</summary>
    public Detour? this[string name]
    {
        get
        {
            _detours.TryGetValue(name, out Detour? detour);
            return detour;
        }
    }

    /// <summary>All detours registered in this manager.</summary>
    public IEnumerable<Detour> All => _detours.Values;

    /// <summary>Removes every applied detour, restoring original bytes.</summary>
    public void RemoveAll()
    {
        foreach (Detour detour in _detours.Values)
        {
            detour.Remove();
        }
    }
}