using System;
using System.Collections;
using System.Collections.Generic;
using Content.Shared.Research;
using Robust.Shared.GameObjects;
using Robust.Shared.IoC;
using Robust.Shared.Prototypes;
using Robust.Shared.Serialization;

namespace Content.Shared.GameObjects.Components.Research
{
    public class SharedTechnologyDatabaseComponent : Component, IEnumerable<TechnologyPrototype>
    {
        public override string Name => "TechnologyDatabase";
        public override uint? NetID => ContentNetIDs.TECHNOLOGY_DATABASE;

        protected List<TechnologyPrototype> _technologies = new List<TechnologyPrototype>();

        /// <summary>
        ///     A read-only list of unlocked technologies.
        /// </summary>
        public IReadOnlyList<TechnologyPrototype> Technologies => _technologies;

        public IEnumerator<TechnologyPrototype> GetEnumerator()
        {
            return Technologies.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }

        /// <summary>
        ///     Returns a list with the IDs of all unlocked technologies.
        /// </summary>
        /// <returns>A list of technology IDs</returns>
        public List<string> GetTechnologyIdList()
        {
            List<string> techIds = new List<string>();

            foreach (var tech in _technologies)
            {
                techIds.Add(tech.ID);
            }

            return techIds;
        }

        /// <summary>
        ///     Returns whether a technology is unlocked on this database or not.
        /// </summary>
        /// <param name="technology">The technology to be checked</param>
        /// <returns>Whether it is unlocked or not</returns>
        public bool IsTechnologyUnlocked(TechnologyPrototype technology)
        {
            return _technologies.Contains(technology);
        }

        /// <summary>
        ///     Returns whether a technology can be unlocked on this database,
        ///     taking parent technologies into account.
        /// </summary>
        /// <param name="technology">The technology to be checked</param>
        /// <returns>Whether it could be unlocked or not</returns>
        public bool CanUnlockTechnology(TechnologyPrototype technology)
        {
            if (technology == null || IsTechnologyUnlocked(technology)) return false;
            var protoMan = IoCManager.Resolve<IPrototypeManager>();
            foreach (var technologyId in technology.RequiredTechnologies)
            {
                protoMan.TryIndex(technologyId, out TechnologyPrototype requiredTechnology);
                if (requiredTechnology == null)
                    return false;

                if (!IsTechnologyUnlocked(requiredTechnology))
                    return false;
            }
            return true;
        }

        public override void ExposeData(ObjectSerializer serializer)
        {
            base.ExposeData(serializer);

            if (serializer.Reading)
            {
                var techs = serializer.ReadDataField("technologies", new List<string>());
                var prototypeManager = IoCManager.Resolve<IPrototypeManager>();
                foreach (var id in techs)
                {
                    if (!prototypeManager.TryIndex(id, out TechnologyPrototype tech)) continue;
                    _technologies.Add(tech);
                }
            } else if (serializer.Writing)
            {
                var techs = GetTechnologyIdList();
                serializer.DataField(ref techs, "technologies", new List<string>());
            }
        }
    }

    [Serializable, NetSerializable]
    public class TechnologyDatabaseState : ComponentState
    {
        public List<string> Technologies;
        public TechnologyDatabaseState(List<string> technologies) : base(ContentNetIDs.TECHNOLOGY_DATABASE)
        {
            Technologies = technologies;
        }

        public TechnologyDatabaseState(List<TechnologyPrototype> technologies) : base(ContentNetIDs.TECHNOLOGY_DATABASE)
        {
            Technologies = new List<string>();
            foreach (var technology in technologies)
            {
                Technologies.Add(technology.ID);
            }
        }
    }
}
