using System.Diagnostics.CodeAnalysis;
using Content.Shared.Forensics.Components;
using Content.Shared.Inventory;
using Content.Shared.Lock;
using Content.Shared.Popups;
using JetBrains.Annotations;

namespace Content.Shared.FingerprintReader;

// TODO: This has a lot of overlap with the AccessReaderSystem, maybe merge them in the future?
public sealed class FingerprintReaderSystem : EntitySystem
{
    [Dependency] private readonly InventorySystem _inventory = default!;
    [Dependency] private readonly SharedPopupSystem _popup = default!;

    public override void Initialize()
    {
        base.Initialize();

        SubscribeLocalEvent<FingerprintReaderComponent, FindAvailableLocksEvent>(OnFindAvailableLocks);
        SubscribeLocalEvent<FingerprintReaderComponent, CheckUserHasLockAccessEvent>(OnCheckLockAccess);
    }

    private void OnFindAvailableLocks(Entity<FingerprintReaderComponent> ent, ref FindAvailableLocksEvent args)
    {
        args.FoundReaders |= LockTypes.Fingerprint;
    }

    private void OnCheckLockAccess(Entity<FingerprintReaderComponent> ent, ref CheckUserHasLockAccessEvent args)
    {
        // Are we looking for a fingerprint lock?
        if (!args.FoundReaders.HasFlag(LockTypes.Fingerprint))
            return;

        // If the user has access to this lock, we pass it into the event.
        if (IsAllowed(ent.Owner, args.User, out var denyReason))
            args.HasAccess |= LockTypes.Fingerprint;
        else
            args.DenyReason = denyReason;
    }

    /// <summary>
    /// Checks if the given user has fingerprint access to the target entity.
    /// </summary>
    /// <param name="target">The target entity.</param>
    /// <param name="user">User trying to gain access.</param>
    /// <param name="showPopup">Whether to display a popup with the reason you are not allowed to access this.</param>
    /// <param name="denyReason">The reason why access was denied.</param>
    /// <returns>True if access was granted, otherwise false.</returns>
    // TODO: Remove showPopup, just keeping it here for backwards compatibility while I refactor mail
    [PublicAPI]
    public bool IsAllowed(Entity<FingerprintReaderComponent?> target, EntityUid user, [NotNullWhen(false)] out string? denyReason, bool showPopup = true)
    {
        denyReason = null;
        if (!Resolve(target, ref target.Comp, false))
            return true;

        if (target.Comp.AllowedFingerprints.Count == 0)
            return true;

        // Check for gloves first
        if (!target.Comp.IgnoreGloves && TryGetBlockingGloves(user, out var gloves))
        {
            denyReason = Loc.GetString("fingerprint-reader-fail-gloves", ("blocker", gloves));

            if (showPopup)
                _popup.PopupClient(denyReason, target, user);

            return false;
        }

        // Check fingerprint match
        if (!TryComp<FingerprintComponent>(user, out var fingerprint) || fingerprint.Fingerprint == null ||
            !target.Comp.AllowedFingerprints.Contains(fingerprint.Fingerprint))
        {
            denyReason = Loc.GetString("fingerprint-reader-fail");

            if (showPopup)
                _popup.PopupClient(denyReason, target, user);

            return false;
        }

        return true;
    }

    /// <summary>
    /// Gets the blocking gloves of a user. Gloves count as blocking if they hide fingerprints.
    /// </summary>
    /// <param name="user">Entity wearing the gloves.</param>
    /// <param name="blocker">The returned gloves, if they exist.</param>
    /// <returns>True if blocking gloves were found, otherwise False.</returns>
    [PublicAPI]
    public bool TryGetBlockingGloves(EntityUid user, [NotNullWhen(true)] out EntityUid? blocker)
    {
        blocker = null;

        if (_inventory.TryGetSlotEntity(user, "gloves", out var gloves) && HasComp<FingerprintMaskComponent>(gloves))
        {
            blocker = gloves;
            return true;
        }

        return false;
    }

    /// <summary>
    /// Sets the allowed fingerprints for a fingerprint reader
    /// </summary>
    [PublicAPI]
    public void SetAllowedFingerprints(Entity<FingerprintReaderComponent> target, HashSet<string> fingerprints)
    {
        target.Comp.AllowedFingerprints = fingerprints;
        Dirty(target);
    }

    /// <summary>
    /// Adds an allowed fingerprint to a fingerprint reader
    /// </summary>
    [PublicAPI]
    public void AddAllowedFingerprint(Entity<FingerprintReaderComponent> target, string fingerprint)
    {
        target.Comp.AllowedFingerprints.Add(fingerprint);
        Dirty(target);
    }

    /// <summary>
    /// Removes an allowed fingerprint from a fingerprint reader
    /// </summary>
    [PublicAPI]
    public void RemoveAllowedFingerprint(Entity<FingerprintReaderComponent> target, string fingerprint)
    {
        target.Comp.AllowedFingerprints.Remove(fingerprint);
        Dirty(target);
    }
}