using System;
using System.Collections.Generic;
using Models;

namespace Core;

/// <summary>
/// 系统层骨架（负责模型变化，不直接处理输入/显示）
/// 设计说明：
/// 1) 每个系统只关注单一职责，形成高内聚低耦合结构。
/// 2) 系统之间通过 GameSession 共享状态，通过事件总线通讯。
/// 注意事项：
/// - 系统逻辑应尽量“幂等”，便于回合重算与调试。
/// 未来扩展：
/// - 可加入“系统执行顺序配置”，支持 Mod 插入新系统。
/// </summary>
public interface IGameSystem
{
	void Initialize(GameSession session);
	void Tick(float delta);
}

public sealed class GameSystems
{
	public TurnSystem Turn { get; } = new();
	public TaskSystem Task { get; } = new();
	public EconomySystem Economy { get; } = new();
	public SynergySystem Synergy { get; } = new();
	public AssignmentSystem Assignment { get; } = new();

	public void Initialize(GameSession session)
	{
		Turn.Initialize(session);
		Task.Initialize(session);
		Economy.Initialize(session);
		Synergy.Initialize(session);
		Assignment.Initialize(session);
	}

	public void Tick(float delta)
	{
		Turn.Tick(delta);
		Synergy.Tick(delta);
		Task.Tick(delta);
		Economy.Tick(delta);
		Assignment.Tick(delta);
	}
}

public sealed class TurnSystem : IGameSystem
{
	private GameSession _session;

	public void Initialize(GameSession session)
	{
		_session = session;
	}

	public void Tick(float delta)
	{
		// 预留：回合推进计时器/阶段切换
	}
}

public sealed class TaskSystem : IGameSystem
{
	private GameSession _session;
	private StatResolver _statResolver;

	public void Initialize(GameSession session)
	{
		_session = session;
		_statResolver = new StatResolver(session);
	}

	public void Tick(float delta)
	{
		if (_session.State.Turn.Phase != GamePhase.Execution)
		{
			return;
		}

		AdvanceTasks(delta);
	}

	/// <summary>
	/// 回合结算（扣除 Deadline，判定完成与失败）
	/// </summary>
	public void ResolveEndOfTurn()
	{
		var state = _session.State;
		var completed = new List<TaskModel>();
		var failed = new List<TaskModel>();

		foreach (var task in state.Tasks.ActiveTasks)
		{
			if (task.Runtime.RemainingTurns > 0)
			{
				task.Runtime.RemainingTurns--;
			}

			if (task.IsCompleted)
			{
				completed.Add(task);
			}
			else if (task.IsFailed)
			{
				failed.Add(task);
			}
		}

		foreach (var task in completed)
		{
			state.Tasks.ActiveTasks.Remove(task);
			state.Tasks.CompletedTasks.Add(task);
			_session.Events.Publish(new TaskCompletedEvent(task));
		}

		foreach (var task in failed)
		{
			state.Tasks.ActiveTasks.Remove(task);
			state.Tasks.FailedTasks.Add(task);
			_session.Events.Publish(new TaskFailedEvent(task));
		}
	}

	private void AdvanceTasks(float delta)
	{
		var state = _session.State;
		if (state.Tasks.ActiveTasks.Count == 0) return;

		var unitIndex = BuildUnitIndex();

		foreach (var task in state.Tasks.ActiveTasks)
		{
			if (task.IsCompleted || task.IsFailed) continue;
			if (task.Kind == TaskKind.Milestone) continue;

			var taskDef = GetTaskDefinition(task);
			var totalPower = 0f;

			foreach (var unitId in task.AssignedUnitIds)
			{
				if (!unitIndex.TryGetValue(unitId, out var entry))
				{
					continue;
				}

				var contribution = GetUnitContribution(entry, task, taskDef, delta);
				totalPower += contribution;
			}

			if (totalPower <= 0f) continue;

			var difficultyScale = task.Runtime.DifficultyScale * GetDifficultyScale(task.Difficulty);
			task.AddProgress(totalPower * delta / difficultyScale);
		}
	}

	private float GetUnitContribution(UnitEntry entry, TaskModel task, TaskDefinition taskDef, float delta)
	{
		var unit = entry.Unit;
		var basePower = GetTaskBasePower(unit, task.Kind);
		if (basePower <= 0f) return 0f;

		var roleMultiplier = GetRoleMultiplier(unit, taskDef);
		var disciplineMultiplier = GetDisciplineMultiplier(unit, taskDef);
		var statusMultiplier = GetStatusMultiplier(entry);
		var requirementMultiplier = GetRequirementMultiplier(unit, taskDef);

		var effectivePower = basePower * roleMultiplier * disciplineMultiplier * statusMultiplier * requirementMultiplier;
		TrackContribution(entry, task, effectivePower * delta);
		return effectivePower;
	}

	private float GetTaskBasePower(UnitModel unit, TaskKind kind)
	{
		var academic = _statResolver.GetAttribute(unit, AttributeType.Academic);
		var engineering = _statResolver.GetAttribute(unit, AttributeType.Engineering);
		var writing = _statResolver.GetAttribute(unit, AttributeType.Writing);
		var financial = _statResolver.GetAttribute(unit, AttributeType.Financial);
		var social = _statResolver.GetAttribute(unit, AttributeType.Social);
		var activation = _statResolver.GetAttribute(unit, AttributeType.Activation);

		return kind switch
		{
			TaskKind.AcademicExploration => academic * 0.6f + writing * 0.4f,
			TaskKind.GrantVertical => writing * 0.4f + social * 0.4f + financial * 0.2f,
			TaskKind.GrantHorizontal => engineering * 0.5f + activation * 0.3f + academic * 0.2f,
			TaskKind.Administrative => activation * 0.6f + social * 0.4f,
			TaskKind.Conference => social * 0.5f + writing * 0.3f + financial * 0.2f,
			TaskKind.Milestone => 0f,
			_ => academic
		};
	}

	private float GetStatusMultiplier(UnitEntry entry)
	{
		var mood = entry.Unit.Statuses.Mood.Normalized;
		var stress = entry.Unit.Statuses.Stress.Current.Normalized;

		var moodMultiplier = 0.5f + mood * 0.5f;
		var stressMultiplier = Math.Clamp(1.0f - 0.3f * stress, 0.7f, 1.0f);
		var multiplier = moodMultiplier * stressMultiplier;

		if (entry.Student != null)
		{
			var stamina = entry.Student.Progress.Stamina.Current.Normalized;
			if (stamina < 0.1f) multiplier *= 0.4f;
			else if (stamina < 0.2f) multiplier *= 0.7f;
		}

		return Math.Clamp(multiplier, 0.3f, 1.2f);
	}

	private float GetRoleMultiplier(UnitModel unit, TaskDefinition taskDef)
	{
		if (taskDef == null) return 1.0f;

		if (taskDef.Requirements.RequiredRoleIds.Count > 0)
		{
			foreach (var roleId in taskDef.Requirements.RequiredRoleIds)
			{
				if (unit.Tags.RoleIds.Contains(roleId))
				{
					return 1.0f;
				}
			}

			return 0.5f;
		}

		if (taskDef.RecommendedRoleIds.Count > 0)
		{
			foreach (var roleId in taskDef.RecommendedRoleIds)
			{
				if (unit.Tags.RoleIds.Contains(roleId))
				{
					return 1.1f;
				}
			}

			return 0.9f;
		}

		return 1.0f;
	}

	private float GetRequirementMultiplier(UnitModel unit, TaskDefinition taskDef)
	{
		if (taskDef == null) return 1.0f;
		var multiplier = 1.0f;

		foreach (var requirement in taskDef.Requirements.AttributeChecks)
		{
			var value = _statResolver.GetAttribute(unit, requirement.Type);
			if (value < requirement.MinValue)
			{
				multiplier *= 0.85f;
			}
		}

		return multiplier;
	}

	private float GetDisciplineMultiplier(UnitModel unit, TaskDefinition taskDef)
	{
		if (taskDef == null) return 1.0f;
		if (taskDef.AllowedDisciplineIds.Count == 0) return 1.0f;
		if (string.IsNullOrWhiteSpace(unit.Tags.DisciplineId)) return 0.8f;

		foreach (var disciplineId in taskDef.AllowedDisciplineIds)
		{
			if (disciplineId == unit.Tags.DisciplineId)
			{
				return 1.0f;
			}
		}

		return 0.7f;
	}

	private float GetDifficultyScale(TaskDifficulty difficulty)
	{
		return difficulty switch
		{
			TaskDifficulty.Water => 0.8f,
			TaskDifficulty.Standard => 1.0f,
			TaskDifficulty.Hardcore => 1.3f,
			TaskDifficulty.BlackBox => 1.6f,
			_ => 1.0f
		};
	}

	private TaskDefinition GetTaskDefinition(TaskModel task)
	{
		if (string.IsNullOrWhiteSpace(task.DefinitionId)) return null;
		return _session.Content.Tasks.TryGetValue(task.DefinitionId, out var definition) ? definition : null;
	}

	private Dictionary<Guid, UnitEntry> BuildUnitIndex()
	{
		var index = new Dictionary<Guid, UnitEntry>();
		var roster = _session.State.Roster;

		if (roster.Mentor != null)
		{
			var unit = roster.Mentor.Core;
			index[unit.Identity.Id] = new UnitEntry(unit, roster.Mentor, null, null);
		}

		foreach (var student in roster.Students)
		{
			var unit = student.Core;
			index[unit.Identity.Id] = new UnitEntry(unit, null, student, null);
		}

		foreach (var staff in roster.Staffs)
		{
			var unit = staff.Core;
			index[unit.Identity.Id] = new UnitEntry(unit, null, null, staff);
		}

		return index;
	}

	private void TrackContribution(UnitEntry entry, TaskModel task, float deltaContribution)
	{
		if (entry.Student == null) return;

		var contributions = entry.Student.Contributions.ByTask;
		if (!contributions.TryGetValue(task.Id, out var value))
		{
			value = new PropertyValue(0, 0, 1000000);
			contributions[task.Id] = value;
		}

		value.Add(deltaContribution);
	}

	private readonly struct UnitEntry
	{
		public UnitModel Unit { get; }
		public MentorModel Mentor { get; }
		public StudentModel Student { get; }
		public StaffModel Staff { get; }

		public UnitEntry(UnitModel unit, MentorModel mentor, StudentModel student, StaffModel staff)
		{
			Unit = unit;
			Mentor = mentor;
			Student = student;
			Staff = staff;
		}
	}
}

public sealed class EconomySystem : IGameSystem
{
	private GameSession _session;
	private const int MasterSalary = 500;
	private const int DoctorSalary = 800;
	private const int PostDocSalary = 1200;
	private const int JuniorFacultySalary = 2000;

	public void Initialize(GameSession session)
	{
		_session = session;
		_session.Events.Subscribe<TaskCompletedEvent>(OnTaskCompleted);
		_session.Events.Subscribe<TaskFailedEvent>(OnTaskFailed);
		_session.Events.Subscribe<TurnEndedEvent>(OnTurnEnded);
	}

	public void Tick(float delta)
	{
		// 当前为回合驱动，不在 Tick 中结算
	}

	private void OnTaskCompleted(TaskCompletedEvent evt)
	{
		var task = evt.Task;
		var economy = _session.State.Economy;
		economy.Money += task.Reward.Money;
		economy.Reputation += task.Reward.Reputation;

		if (task.Reward.PaperIds.Count > 0)
		{
			foreach (var paperId in task.Reward.PaperIds)
			{
				if (_session.Content.Papers.TryGetValue(paperId, out var paper))
				{
					AddPaper(paper.Rank);
				}
			}
		}
		else if (task.Kind == TaskKind.AcademicExploration)
		{
			AddPaper(GetPaperRankByDifficulty(task.Difficulty));
		}

		foreach (var itemId in task.Reward.ItemIds)
		{
			AddItem(itemId, 1);
		}
	}

	private void OnTaskFailed(TaskFailedEvent evt)
	{
		var task = evt.Task;
		var penalty = task.Track == TaskTrack.Tenure ? 20 : 10;
		if (task.Kind == TaskKind.GrantVertical) penalty += 10;
		_session.State.Economy.Reputation -= penalty;
	}

	private void OnTurnEnded(TurnEndedEvent evt)
	{
		ApplySalaries();
		ApplyInterest();
	}

	private void ApplySalaries()
	{
		var economy = _session.State.Economy;
		foreach (var student in _session.State.Roster.Students)
		{
			economy.Money -= student.Type == StudentModel.StudentType.MasterCandidate
				? MasterSalary
				: DoctorSalary;
		}

		foreach (var staff in _session.State.Roster.Staffs)
		{
			economy.Money -= staff.Type == StaffModel.StaffType.PostDoc
				? PostDocSalary
				: JuniorFacultySalary;
		}
	}

	private void ApplyInterest()
	{
		var economy = _session.State.Economy;
		UpdateInterestRate();
		if (economy.Money <= 0 || economy.InterestRate <= 0) return;

		var interest = (int)(economy.Money * economy.InterestRate);
		economy.Money += interest;
	}

	private void UpdateInterestRate()
	{
		var economy = _session.State.Economy;
		var mentor = _session.State.Roster.Mentor;
		if (mentor?.Core.Tags.DisciplineId == CoreIds.DisciplineEconomics)
		{
			economy.InterestRate = Math.Max(economy.InterestRate, 0.1f);
		}
	}

	private void AddPaper(PaperRank rank)
	{
		var inventory = _session.State.Inventory;
		if (!inventory.PaperCounts.ContainsKey(rank))
		{
			inventory.PaperCounts[rank] = 0;
		}

		inventory.PaperCounts[rank] += 1;
	}

	private void AddItem(string itemId, int count)
	{
		if (string.IsNullOrWhiteSpace(itemId)) return;
		var inventory = _session.State.Inventory;
		if (!inventory.ItemCounts.ContainsKey(itemId))
		{
			inventory.ItemCounts[itemId] = 0;
		}

		inventory.ItemCounts[itemId] += count;
	}

	private PaperRank GetPaperRankByDifficulty(TaskDifficulty difficulty)
	{
		return difficulty switch
		{
			TaskDifficulty.Water => PaperRank.C,
			TaskDifficulty.Standard => PaperRank.B,
			TaskDifficulty.Hardcore => PaperRank.A,
			TaskDifficulty.BlackBox => PaperRank.S,
			_ => PaperRank.C
		};
	}
}

public sealed class SynergySystem : IGameSystem
{
	private GameSession _session;

	public void Initialize(GameSession session)
	{
		_session = session;
	}

	public void Tick(float delta)
	{
		RecalculateSynergy();
	}

	private void RecalculateSynergy()
	{
		var state = _session.State.Synergy;
		state.ArchetypeStacks.Clear();
		state.RoleStacks.Clear();
		state.ActiveSynergyIds.Clear();
		ClearModifiers(state.ActiveModifiers);

		CountUnitTags(state);
		ApplySynergyDefinitions(state);
	}

	private void CountUnitTags(SynergyState synergy)
	{
		var roster = _session.State.Roster;
		AddUnitTags(synergy, roster.Mentor?.Core);

		foreach (var student in roster.Students)
		{
			AddUnitTags(synergy, student.Core);
		}

		foreach (var staff in roster.Staffs)
		{
			AddUnitTags(synergy, staff.Core);
		}
	}

	private void AddUnitTags(SynergyState synergy, UnitModel unit)
	{
		if (unit == null) return;
		foreach (var archetypeId in unit.Tags.ArchetypeIds)
		{
			AddStack(synergy.ArchetypeStacks, archetypeId);
		}

		foreach (var roleId in unit.Tags.RoleIds)
		{
			AddStack(synergy.RoleStacks, roleId);
		}
	}

	private void AddStack(Dictionary<string, int> stacks, string id)
	{
		if (string.IsNullOrWhiteSpace(id)) return;
		if (!stacks.ContainsKey(id))
		{
			stacks[id] = 0;
		}

		stacks[id] += 1;
	}

	private void ApplySynergyDefinitions(SynergyState synergy)
	{
		foreach (var archetype in _session.Content.Archetypes.Values)
		{
			ApplySynergyTier(archetype.Header.Id, archetype.Tiers, synergy.ArchetypeStacks, synergy);
		}

		foreach (var role in _session.Content.Roles.Values)
		{
			ApplySynergyTier(role.Header.Id, role.Tiers, synergy.RoleStacks, synergy);
		}
	}

	private void ApplySynergyTier(string id, List<SynergyTier> tiers, Dictionary<string, int> stacks, SynergyState synergy)
	{
		if (string.IsNullOrWhiteSpace(id)) return;
		stacks.TryGetValue(id, out var count);

		foreach (var tier in tiers)
		{
			if (count < tier.RequiredCount) continue;
			var synergyId = $"{id}@{tier.RequiredCount}";
			synergy.ActiveSynergyIds.Add(synergyId);
			MergeModifiers(synergy.ActiveModifiers, tier.Modifiers);
		}
	}

	private void MergeModifiers(ModifierBundle target, ModifierBundle source)
	{
		if (target == null || source == null) return;
		target.AttributeModifiers.AddRange(source.AttributeModifiers);
		target.StatusModifiers.AddRange(source.StatusModifiers);
		target.ResourceModifiers.AddRange(source.ResourceModifiers);
		target.RuleIds.AddRange(source.RuleIds);
	}

	private void ClearModifiers(ModifierBundle bundle)
	{
		bundle.AttributeModifiers.Clear();
		bundle.StatusModifiers.Clear();
		bundle.ResourceModifiers.Clear();
		bundle.RuleIds.Clear();
	}
}

public sealed class AssignmentSystem : IGameSystem
{
	private GameSession _session;

	public void Initialize(GameSession session)
	{
		_session = session;
	}

	public void Tick(float delta)
	{
		// 预留：人员分配、交接惩罚等
	}
}