using System;
using System.Collections.Generic;
using UnityEngine;

namespace IdleSpectator;

/// <summary>World-session narrative state. Updated from developments; independent of Saga roster churn.</summary>
public static class NarrativeStoryStore
{
    private const int RecentPerCharacter = 16;
    private const int ConsequencesPerCharacter = 24;
    private static readonly Dictionary<string, NarrativeDevelopment> Developments =
        new Dictionary<string, NarrativeDevelopment>(StringComparer.Ordinal);
    private static readonly Dictionary<long, CharacterStoryState> Characters =
        new Dictionary<long, CharacterStoryState>();
    private static readonly Dictionary<string, NarrativeThread> Threads =
        new Dictionary<string, NarrativeThread>(StringComparer.Ordinal);
    private static readonly Dictionary<string, CharacterConsequence> Consequences =
        new Dictionary<string, CharacterConsequence>(StringComparer.Ordinal);
    private static readonly List<NarrativeThread> ThreadScratch = new List<NarrativeThread>(32);

    public static int Revision { get; private set; }
    public static int DevelopmentCount => Developments.Count;
    public static int ThreadCount => Threads.Count;
    public static int CharacterCount => Characters.Count;

    public static void Clear()
    {
        Developments.Clear();
        Characters.Clear();
        Threads.Clear();
        Consequences.Clear();
        ThreadScratch.Clear();
        NarrativeEventStore.Clear();
        Revision++;
        StoryScheduler.Clear();
        NarrativeTelemetry.Clear();
        NarrativePresentationCoverage.Clear();
    }

    public static CharacterStoryState Character(long id)
    {
        Characters.TryGetValue(id, out CharacterStoryState state);
        return state;
    }

    public static NarrativeDevelopment Development(string id)
    {
        if (string.IsNullOrEmpty(id)) return null;
        Developments.TryGetValue(id, out NarrativeDevelopment development);
        return development;
    }

    public static NarrativeThread Thread(string id)
    {
        if (string.IsNullOrEmpty(id)) return null;
        Threads.TryGetValue(id, out NarrativeThread thread);
        return thread;
    }

    public static CharacterConsequence Consequence(string id)
    {
        if (string.IsNullOrEmpty(id)) return null;
        Consequences.TryGetValue(id, out CharacterConsequence consequence);
        return consequence;
    }

    internal static IEnumerable<NarrativeDevelopment> AllDevelopments() => Developments.Values;
    internal static IEnumerable<NarrativeThread> AllThreads() => Threads.Values;
    internal static IEnumerable<CharacterConsequence> AllConsequences() => Consequences.Values;
    internal static IEnumerable<CharacterStoryState> AllCharacters() => Characters.Values;

    internal static void ImportDevelopment(NarrativeDevelopment development)
    {
        if (development != null && development.SubjectId != 0
            && !string.IsNullOrEmpty(development.Id))
        {
            Developments[development.Id] = development;
        }
    }

    internal static void ImportThread(NarrativeThread thread)
    {
        if (thread != null && !string.IsNullOrEmpty(thread.Id))
        {
            Threads[thread.Id] = thread;
        }
    }

    internal static void ImportConsequence(CharacterConsequence consequence)
    {
        if (consequence != null && !string.IsNullOrEmpty(consequence.Id))
        {
            Consequences[consequence.Id] = consequence;
        }
    }

    internal static void ImportCharacter(CharacterStoryState character)
    {
        if (character != null && character.CharacterId != 0)
        {
            Characters[character.CharacterId] = character;
        }
    }

    internal static void FinishImport()
    {
        foreach (CharacterStoryState state in Characters.Values)
        {
            if (state == null) continue;
            state.OpenThreadIds.RemoveAll(id => !Threads.ContainsKey(id));
            state.ResolvedThreadIds.RemoveAll(id => !Threads.ContainsKey(id));
            state.RecentDevelopmentIds.RemoveAll(id => !Developments.ContainsKey(id));
            state.ConsequenceIds.RemoveAll(id => !Consequences.ContainsKey(id));
        }

        Revision++;
        StoryScheduler.Clear();
        NarrativeTelemetry.Clear();
        NarrativePresentationCoverage.Clear();
    }

    public static bool Record(NarrativeDevelopment development)
    {
        if (development == null || development.SubjectId == 0 || string.IsNullOrEmpty(development.Id))
        {
            return false;
        }

        if (Developments.TryGetValue(development.Id, out NarrativeDevelopment existing))
        {
            existing.OccurredAt = Mathf.Max(existing.OccurredAt, development.OccurredAt);
            existing.Magnitude = Mathf.Max(existing.Magnitude, development.Magnitude);
            existing.Confidence = Mathf.Max(existing.Confidence, development.Confidence);
            existing.IsNewStateChange = false;
            return false;
        }

        Developments[development.Id] = development;
        CharacterStoryState subject = GetOrCreateCharacter(development.SubjectId, development.Subject);
        TouchDevelopment(subject, development);
        if (development.OtherId != 0)
        {
            GetOrCreateCharacter(development.OtherId, development.Other);
        }

        NarrativeThreadRules.Apply(development);
        Revision++;
        return true;
    }

    public static NarrativeThread OpenOrUpdateThread(
        string id,
        NarrativeThreadKind kind,
        long protagonistId,
        string anchor,
        NarrativeDevelopment development,
        string centralQuestion,
        NarrativePhase phase,
        NarrativeThreadStatus status)
    {
        if (string.IsNullOrEmpty(id) || protagonistId == 0 || development == null) return null;
        bool created = !Threads.TryGetValue(id, out NarrativeThread thread);
        if (created)
        {
            thread = new NarrativeThread
            {
                Id = id,
                Kind = kind,
                ProtagonistId = protagonistId,
                AnchorKey = anchor ?? "",
                OpenedByDevelopmentId = development.Id,
                OpenedAt = development.OccurredAt,
                Coherence = 1f,
                Novelty = 1f
            };
            Threads[id] = thread;
        }

        thread.Kind = kind;
        thread.CentralQuestion = centralQuestion ?? thread.CentralQuestion;
        thread.Phase = phase;
        thread.Status = status;
        thread.UpdatedAt = development.OccurredAt;
        thread.LatestMeaningfulChangeId = development.Id;
        if (!thread.DevelopmentIds.Contains(development.Id)) thread.DevelopmentIds.Add(development.Id);
        thread.AddCast(protagonistId, "protagonist");
        if (development.OtherId != 0) thread.AddCast(development.OtherId, CastRole(development.Kind));
        thread.Momentum = Mathf.Min(12f, thread.Momentum + MomentumFor(development.Function));
        thread.Urgency = Mathf.Max(thread.Urgency, UrgencyFor(development));

        LifeSagaIdentity protagonistIdentity = protagonistId == development.SubjectId
            ? development.Subject
            : (protagonistId == development.OtherId ? development.Other : default);
        CharacterStoryState state = GetOrCreateCharacter(protagonistId, protagonistIdentity);
        MoveThreadReference(state, thread);
        RecalculatePotential(state);
        Revision++;
        return thread;
    }

    public static void AddConsequence(CharacterConsequence consequence)
    {
        if (consequence == null || consequence.CharacterId == 0 || string.IsNullOrEmpty(consequence.Id)) return;
        if (Consequences.ContainsKey(consequence.Id)) return;
        Consequences[consequence.Id] = consequence;
        CharacterStoryState state = GetOrCreateCharacter(consequence.CharacterId, default);
        state.ConsequenceIds.Insert(0, consequence.Id);
        while (state.ConsequenceIds.Count > ConsequencesPerCharacter)
        {
            state.ConsequenceIds.RemoveAt(state.ConsequenceIds.Count - 1);
        }

        RecalculatePotential(state);
        Revision++;
    }

    public static void CopyOpenThreads(List<NarrativeThread> into)
    {
        if (into == null) return;
        into.Clear();
        foreach (NarrativeThread thread in Threads.Values)
        {
            if (thread != null
                && (thread.IsOpen
                    || (thread.Status == NarrativeThreadStatus.Resolved
                        && Time.unscaledTime - thread.UpdatedAt < 20f)))
            {
                into.Add(thread);
            }
        }
    }

    /// <summary>Copies bounded story-potential challengers without scanning the world.</summary>
    public static void CopyEmergingCharacters(List<CharacterStoryState> into, float minimumPotential, int max)
    {
        if (into == null) return;
        into.Clear();
        float now = Time.unscaledTime;
        foreach (CharacterStoryState state in Characters.Values)
        {
            if (state != null && state.CharacterId != 0
                && EffectiveStoryPotential(state, now) >= minimumPotential)
            {
                into.Add(state);
            }
        }

        into.Sort((a, b) => EffectiveStoryPotential(b, now).CompareTo(EffectiveStoryPotential(a, now)));
        if (max > 0 && into.Count > max) into.RemoveRange(max, into.Count - max);
    }

    public static float EffectiveStoryPotential(CharacterStoryState state, float now = -1f)
    {
        if (state == null) return 0f;
        if (now < 0f) now = Time.unscaledTime;
        float age = Mathf.Max(0f, now - state.LastMeaningfulChangeAt);
        // Narrative momentum has a long half-life, but is not a permanent celebrity badge.
        float freshness = Mathf.Pow(0.5f, age / 300f);
        return state.StoryPotential * freshness;
    }

    public static NarrativeDevelopment LatestFor(long characterId, NarrativeDevelopmentKind kind, float maxAge)
    {
        CharacterStoryState state = Character(characterId);
        if (state == null) return null;
        float now = Time.unscaledTime;
        for (int i = 0; i < state.RecentDevelopmentIds.Count; i++)
        {
            NarrativeDevelopment development = Development(state.RecentDevelopmentIds[i]);
            if (development == null || development.Kind != kind) continue;
            if (maxAge > 0f && now - development.OccurredAt > maxAge) continue;
            return development;
        }

        return null;
    }

    public static List<NarrativeChapter> ChaptersFor(long characterId, int max)
    {
        var chapters = new List<NarrativeChapter>(Mathf.Max(0, max));
        CharacterStoryState state = Character(characterId);
        if (state == null || max <= 0) return chapters;
        var seenThreads = new HashSet<string>(StringComparer.Ordinal);
        for (int i = 0; i < state.ConsequenceIds.Count && chapters.Count < max; i++)
        {
            CharacterConsequence consequence = Consequence(state.ConsequenceIds[i]);
            if (consequence == null || consequence.Confidence < 0.75f) continue;
            string line;
            if (consequence.Kind == CharacterConsequenceKind.BecameParent)
            {
                int children = CountConsequences(characterId, CharacterConsequenceKind.BecameParent);
                line = children >= 3 ? "Raised a lineage of " + children + " children"
                    : NarrativeProse.ConsequenceLine(consequence);
            }
            else
            {
                line = NarrativeProse.ConsequenceLine(consequence);
            }
            if (string.IsNullOrEmpty(line)) continue;
            if (!string.IsNullOrEmpty(consequence.ThreadId) && !seenThreads.Add(consequence.ThreadId))
            {
                NarrativeChapter current = FindChapter(chapters, consequence.ThreadId);
                string merged = NarrativeProse.TryMergeChapter(current?.Line, consequence);
                if (current != null && !string.IsNullOrEmpty(merged))
                {
                    current.Line = merged;
                    current.Importance = Mathf.Max(current.Importance, consequence.Importance);
                }

                continue;
            }

            chapters.Add(new NarrativeChapter
            {
                Id = consequence.Id,
                ThreadId = consequence.ThreadId,
                Line = line,
                DateLabel = consequence.DateLabel ?? "",
                At = consequence.OccurredAt,
                Importance = consequence.Importance
            });
        }

        chapters.Sort((a, b) => b.Importance.CompareTo(a.Importance));
        return chapters;
    }

    public static int CountConsequences(long characterId, CharacterConsequenceKind kind)
    {
        CharacterStoryState state = Character(characterId);
        if (state == null) return 0;
        int count = 0;
        for (int i = 0; i < state.ConsequenceIds.Count; i++)
        {
            CharacterConsequence c = Consequence(state.ConsequenceIds[i]);
            if (c != null && c.Kind == kind) count++;
        }

        return count;
    }

    private static CharacterStoryState GetOrCreateCharacter(long id, LifeSagaIdentity identity)
    {
        if (!Characters.TryGetValue(id, out CharacterStoryState state))
        {
            state = new CharacterStoryState { CharacterId = id, Identity = identity };
            Characters[id] = state;
        }
        else if (identity.Id != 0)
        {
            state.Identity = identity;
        }

        return state;
    }

    private static void TouchDevelopment(CharacterStoryState state, NarrativeDevelopment development)
    {
        state.RecentDevelopmentIds.Insert(0, development.Id);
        while (state.RecentDevelopmentIds.Count > RecentPerCharacter)
        {
            state.RecentDevelopmentIds.RemoveAt(state.RecentDevelopmentIds.Count - 1);
        }

        state.LastMeaningfulChangeAt = development.OccurredAt;
        state.StoryMomentum = Mathf.Min(12f, state.StoryMomentum + MomentumFor(development.Function));
        RecalculatePotential(state);
    }

    private static void MoveThreadReference(CharacterStoryState state, NarrativeThread thread)
    {
        state.OpenThreadIds.Remove(thread.Id);
        state.ResolvedThreadIds.Remove(thread.Id);
        if (thread.IsOpen) state.OpenThreadIds.Insert(0, thread.Id);
        else state.ResolvedThreadIds.Insert(0, thread.Id);
    }

    private static void RecalculatePotential(CharacterStoryState state)
    {
        if (state == null) return;
        float unresolved = state.OpenThreadIds.Count * 2.5f;
        float consequences = Mathf.Min(6f, state.ConsequenceIds.Count * 0.8f);
        state.StoryPotential = state.StoryMomentum + unresolved + consequences;
    }

    private static float MomentumFor(NarrativeFunction function)
    {
        switch (function)
        {
            case NarrativeFunction.ThreadOpener: return 2f;
            case NarrativeFunction.Development: return 1.5f;
            case NarrativeFunction.Escalation: return 2.5f;
            case NarrativeFunction.TurningPoint: return 4f;
            case NarrativeFunction.Resolution: return 3.5f;
            case NarrativeFunction.Consequence: return 3f;
            default: return 0.25f;
        }
    }

    private static float UrgencyFor(NarrativeDevelopment development)
    {
        if (development == null) return 0f;
        if (development.Function == NarrativeFunction.TurningPoint) return 4f;
        if (development.Function == NarrativeFunction.Resolution) return 3f;
        return Mathf.Clamp(development.Magnitude / 25f, 0f, 3f);
    }

    private static string CastRole(NarrativeDevelopmentKind kind)
    {
        switch (kind)
        {
            case NarrativeDevelopmentKind.BondFormed:
            case NarrativeDevelopmentKind.BondBroken: return "partner";
            case NarrativeDevelopmentKind.ChildBorn: return "child";
            case NarrativeDevelopmentKind.FriendFormed: return "friend";
            case NarrativeDevelopmentKind.Kill:
            case NarrativeDevelopmentKind.RivalEncounter: return "opponent";
            default: return "involved";
        }
    }

    private static NarrativeChapter FindChapter(List<NarrativeChapter> chapters, string threadId)
    {
        for (int i = 0; i < chapters.Count; i++)
        {
            if (chapters[i] != null && string.Equals(chapters[i].ThreadId, threadId, StringComparison.Ordinal))
            {
                return chapters[i];
            }
        }

        return null;
    }
}