using System;
using Server.Gumps;
using Server.Mobiles;

namespace Server.Engines.MLQuests.Objectives
{
  public enum GainSkillObjectiveFlags : byte
  {
    None = 0x00,
    UseReal = 0x01,
    Accelerate = 0x02
  }

  public class GainSkillObjective : BaseObjective
  {
    private GainSkillObjectiveFlags m_Flags;

    public GainSkillObjective()
      : this(SkillName.Alchemy, 0)
    {
    }

    public GainSkillObjective(SkillName skill, int thresholdFixed)
      : this(skill, thresholdFixed, false, false)
    {
    }

    public GainSkillObjective(SkillName skill, int thresholdFixed, bool useReal, bool accelerate)
    {
      Skill = skill;
      ThresholdFixed = thresholdFixed;
      m_Flags = GainSkillObjectiveFlags.None;

      if (useReal)
        m_Flags |= GainSkillObjectiveFlags.UseReal;

      if (accelerate)
        m_Flags |= GainSkillObjectiveFlags.Accelerate;
    }

    public SkillName Skill{ get; set; }

    public int ThresholdFixed{ get; set; }

    public bool UseReal
    {
      get => GetFlag(GainSkillObjectiveFlags.UseReal);
      set => SetFlag(GainSkillObjectiveFlags.UseReal, value);
    }

    public bool Accelerate
    {
      get => GetFlag(GainSkillObjectiveFlags.Accelerate);
      set => SetFlag(GainSkillObjectiveFlags.Accelerate, value);
    }

    public override bool CanOffer(IQuestGiver quester, PlayerMobile pm, bool message)
    {
      Skill skill = pm.Skills[Skill];

      if ((UseReal ? skill.Fixed : skill.BaseFixedPoint) >= ThresholdFixed)
      {
        if (message)
          MLQuestSystem.Tell(quester, pm, 1077772); // I cannot teach you, for you know all I can teach!

        return false;
      }

      return true;
    }

    public override void WriteToGump(Gump g, ref int y)
    {
      int skillLabel = AosSkillBonuses.GetLabel(Skill);
      string args;

      if (ThresholdFixed % 10 == 0)
        args = $"#{skillLabel}\t{ThresholdFixed / 10}"; // as seen on OSI
      else
        args = $"#{skillLabel}\t{(double)ThresholdFixed / 10:0.0}"; // for non-integer skill levels

      g.AddHtmlLocalized(98, y, 312, 16, 1077485, args, 0x15F90, false, false); // Increase ~1_SKILL~ to ~2_VALUE~
      y += 16;
    }

    public override BaseObjectiveInstance CreateInstance(MLQuestInstance instance)
    {
      return new GainSkillObjectiveInstance(this, instance);
    }

    private bool GetFlag(GainSkillObjectiveFlags flag)
    {
      return (m_Flags & flag) != 0;
    }

    private void SetFlag(GainSkillObjectiveFlags flag, bool value)
    {
      if (value)
        m_Flags |= flag;
      else
        m_Flags &= ~flag;
    }
  }

  // On OSI, once this is complete, it will *stay* complete, even if you lower your skill again
  public class GainSkillObjectiveInstance : BaseObjectiveInstance
  {
    public GainSkillObjectiveInstance(GainSkillObjective objective, MLQuestInstance instance)
      : base(instance, objective)
    {
      Objective = objective;
    }

    public GainSkillObjective Objective{ get; set; }

    public bool Handles(SkillName skill)
    {
      return Objective.Skill == skill;
    }

    public override bool IsCompleted()
    {
      PlayerMobile pm = Instance.Player;

      int valueFixed = Objective.UseReal
        ? pm.Skills[Objective.Skill].Fixed
        : pm.Skills[Objective.Skill].BaseFixedPoint;

      return valueFixed >= Objective.ThresholdFixed;
    }

    // TODO: This may interfere with scrolls, or even quests among each other
    // How does OSI deal with this?
    public override void OnQuestAccepted()
    {
      if (!Objective.Accelerate)
        return;

      PlayerMobile pm = Instance.Player;

      pm.AcceleratedSkill = Objective.Skill;
      pm.AcceleratedStart = DateTime.UtcNow + TimeSpan.FromMinutes(15); // TODO: Is there a max duration?
    }

    public override void OnQuestCancelled()
    {
      if (!Objective.Accelerate)
        return;

      PlayerMobile pm = Instance.Player;

      pm.AcceleratedStart = DateTime.UtcNow;
      pm.PlaySound(0x100);
    }

    public override void OnQuestCompleted()
    {
      OnQuestCancelled();
    }

    public override void WriteToGump(Gump g, ref int y)
    {
      Objective.WriteToGump(g, ref y);

      base.WriteToGump(g, ref y);

      if (IsCompleted())
      {
        g.AddHtmlLocalized(113, y, 312, 20, 1055121, 0xFFFFFF, false, false); // Complete
        y += 16;
      }
    }
  }
}