import { useRemoteReducer } from "@common/hooks/useRemote";
import { createContext } from "preact";
import { useContext, useMemo } from "preact/hooks";
import Chapters from "../utils/chapters";
import LLM from "../utils/llm";

// ─── Types ────────────────────────────────────────────────────────────────────

export type ChatMessage = LLM.ChatMessage & {
    id: string;
}

export type Tab = "story" | "lore" | "characters" | "locations" | "chapters" | "scratchpad" | "prompt" | "menu" | "system" | "chat";

export enum CharacterRole {
    Protagonist = 'protagonist',
    Antagonist = 'antagonist',
    Main = 'main',
    Secondary = 'secondary',
    Supporting = 'supporting',
    Minor = 'minor',
    Cameo = 'cameo',
}

export interface Character {
    id: string;
    name: string;
    role: CharacterRole;
    nicknames: string[];
    shortDescription: string;
    description: string;
    // Meaningful relationships with other characters
    relations: ({
        name: string; // character full name
        relation: string; // daughter/friend/neighbour/etc
    })[];
}

export enum LocationScale {
    Room = 'room',
    House = 'house',
    Street = 'street',
    Village = 'village',
    City = 'city',
    Region = 'region',
    Country = 'country',
    Continent = 'continent',
    World = 'world',
    Universe = 'universe',
}

export interface Location {
    id: string;
    name: string;
    shortDescription: string;
    description: string;
    scale: LocationScale;
}

export interface LoreEntry {
    id: string;
    title: string;
    text: string;
}

export interface GenerationSettings {
    temperature: number;
    top_p: number;
    top_k: number;
    min_p: number;
    repetition_penalty: number;
    frequency_penalty: number;
}

export interface ImageGenerationSettings {
    width: number;
    height: number;
    negative_prompt: string;
    sampler_name: LLM.ImageSamplerName;
}

export const DEFAULT_IMAGE_GENERATION_SETTINGS: ImageGenerationSettings = {
    width: 768,
    height: 768,
    negative_prompt: 'ugly face, bad face, no face, poorly drawn face, greyscale, depth of field, mutated fingers, mutated hands, extra fingers, deformed, ugly, bad anatomy, bad proportions, extra limbs, signature, text, lowres, error, missing fingers, missing limbs, extra digit, fewer digits, cropped, worst quality, low quality, normal quality, jpeg artifacts, watermark, username, blurry, artist name',
    sampler_name: LLM.ImageSamplerName.KEulerA,
};

export const DEFAULT_GENERATION_SETTINGS: GenerationSettings = {
    temperature: 0.8,
    top_p: 0.92,
    top_k: 100,
    min_p: 0.1,
    repetition_penalty: 1.08,
    frequency_penalty: 0,
};

export interface Story {
    id: string;
    title: string;
    text: string;
    scratchpad: string;
    lore: LoreEntry[];
    characters: Character[];
    locations: Location[];
    chatMessages: ChatMessage[];
    chapters: Chapters.Chapter[];
    lastEditedText?: string;
    titleWasChanged?: boolean;
}

export interface World {
    id: string;
    title: string;
    chatOnly: boolean;
    lore: LoreEntry[];
    characters: Character[];
    locations: Location[];
    stories: Story[];
    systemInstructionOverride?: string;
}

// ─── Type Guards ──────────────────────────────────────────────────────────────

export function isWorld(obj: unknown): obj is World {
    if (typeof obj !== 'object' || obj === null) return false;
    const w = obj as Record<string, unknown>;
    return (
        typeof w.id === 'string' &&
        typeof w.title === 'string' &&
        typeof w.chatOnly === 'boolean' &&
        Array.isArray(w.lore) &&
        Array.isArray(w.characters) &&
        Array.isArray(w.locations) &&
        Array.isArray(w.stories)
    );
}

export function isStory(obj: unknown): obj is Story {
    if (typeof obj !== 'object' || obj === null) return false;
    const s = obj as Record<string, unknown>;
    return (
        typeof s.id === 'string' &&
        typeof s.title === 'string' &&
        typeof s.text === 'string' &&
        Array.isArray(s.lore) &&
        Array.isArray(s.characters) &&
        Array.isArray(s.locations) &&
        Array.isArray(s.chatMessages)
    );
}

// ─── State ───────────────────────────────────────────────────────────────────

interface IState {
    worlds: World[];
    currentWorldId: string | null;
    currentStoryId: string | null;
    currentTab: Tab;
    chatOpen: boolean;
    connection: LLM.Connection | null;
    model: LLM.ModelInfoText | null;
    imageModel: LLM.ModelInfoImage | null;
    enableThinking: boolean;
    bannedTokens: string[];
    systemInstruction: string;
    chatSystemInstruction: string;
    continuePrompt: string;
    userName: string;
    userDescription: string;
    generationSettings: GenerationSettings;
    imageGenerationSettings: ImageGenerationSettings;
}

// ─── Actions ─────────────────────────────────────────────────────────────────

type Action =
    // World actions
    | { type: 'CREATE_WORLD'; title: string; chatOnly?: boolean }
    | { type: 'RENAME_WORLD'; worldId: string; title: string }
    | { type: 'DELETE_WORLD'; worldId: string }
    | { type: 'SELECT_WORLD'; worldId: string }
    // Story actions
    | { type: 'CREATE_STORY'; worldId: string }
    | { type: 'RENAME_STORY'; worldId: string; id: string; title: string }
    | { type: 'EDIT_STORY'; worldId: string; id: string; text: string; highlightText?: string }
    | { type: 'EDIT_SCRATCHPAD'; worldId: string; id: string; text: string }
    | { type: 'DELETE_STORY'; worldId: string; id: string }
    | { type: 'SELECT_STORY'; worldId: string; id: string }
    | { type: 'DUPLICATE_STORY'; worldId: string; id: string; upToMessageId?: string }
    // Story lore
    | { type: 'ADD_LORE_ENTRY'; worldId: string; storyId: string | null; entry: LoreEntry }
    | { type: 'EDIT_LORE_ENTRY'; worldId: string; storyId: string | null; entryId: string; updates: Partial<LoreEntry> }
    | { type: 'DELETE_LORE_ENTRY'; worldId: string; storyId: string | null; entryId: string }
    | { type: 'REORDER_LORE_ENTRIES'; worldId: string; storyId: string | null; entryIds: string[] }
    // Settings
    | { type: 'SET_GENERATION_SETTINGS'; settings: Partial<GenerationSettings> }
    | { type: 'SET_IMAGE_GENERATION_SETTINGS'; settings: Partial<ImageGenerationSettings> }
    | { type: 'SET_USER_NAME'; userName: string }
    | { type: 'SET_USER_DESCRIPTION'; userDescription: string }
    | { type: 'SET_SYSTEM_INSTRUCTION'; systemInstruction: string }
    | { type: 'SET_CHAT_SYSTEM_INSTRUCTION'; chatSystemInstruction: string }
    | { type: 'SET_CONTINUE_PROMPT'; continuePrompt: string }
    | { type: 'SET_WORLD_SYSTEM_INSTRUCTION_OVERRIDE'; worldId: string; systemInstructionOverride: string | undefined }
    | { type: 'SET_CURRENT_TAB'; tab: Tab }
    | { type: 'SET_CHAT_OPEN'; open: boolean }
    // Chat
    | { type: 'ADD_CHAT_MESSAGE'; worldId: string; storyId: string; message: ChatMessage }
    | { type: 'DELETE_CHAT_MESSAGES_FROM'; worldId: string; storyId: string; messageId: string }
    | { type: 'EDIT_CHAT_MESSAGE'; worldId: string; storyId: string; messageId: string; content: string }
    // Connection
    | { type: 'SET_CONNECTION'; connection: LLM.Connection | null }
    | { type: 'SET_MODEL'; model: LLM.ModelInfoText | null }
    | { type: 'SET_IMAGE_MODEL'; model: LLM.ModelInfoImage | null }
    | { type: 'SET_ENABLE_THINKING'; enable: boolean }
    | { type: 'SET_BANNED_TOKENS'; tokens: string[] }
    // Characters
    | { type: 'ADD_CHARACTER'; worldId: string; storyId: string | null; character: Character }
    | { type: 'EDIT_CHARACTER'; worldId: string; storyId: string | null; characterId: string; updates: Partial<Omit<Character, 'id' | 'name' | 'relations'>> }
    | { type: 'DELETE_CHARACTER'; worldId: string; storyId: string | null; characterId: string }
    | { type: 'ADD_CHARACTER_RELATION'; worldId: string; storyId: string | null; characterId: string; relation: Character['relations'][number] }
    | { type: 'EDIT_CHARACTER_RELATION'; worldId: string; storyId: string | null; characterId: string; targetName: string; updates: Partial<Character['relations'][number]> }
    | { type: 'DELETE_CHARACTER_RELATION'; worldId: string; storyId: string | null; characterId: string; targetName: string }
    // Locations
    | { type: 'ADD_LOCATION'; worldId: string; storyId: string | null; location: Location }
    | { type: 'EDIT_LOCATION'; worldId: string; storyId: string | null; locationId: string; updates: Partial<Location> }
    | { type: 'DELETE_LOCATION'; worldId: string; storyId: string | null; locationId: string }
    // Chapters
    | { type: 'STORE_CHAPTER_SUMMARY'; worldId: string; storyId: string; header: string; hash: Chapters.Hash; summary: string }
    | { type: 'CLEAN_CHAPTER_SUMMARIES'; worldId: string; storyId: string; validHashes: Record<string, Chapters.Hash[]> }
    // Import/Export
    | { type: 'IMPORT_WORLD'; world: World }
    | { type: 'IMPORT_STORY'; worldId: string; story: Story };

// ─── Helpers ─────────────────────────────────────────────────────────────────

function updateWorld(state: IState, worldId: string, updater: (w: World) => World): IState {
    return {
        ...state,
        worlds: state.worlds.map(w => w.id === worldId ? updater(w) : w),
    };
}

function updateStory(state: IState, worldId: string, storyId: string, updater: (s: Story) => Story): IState {
    return updateWorld(state, worldId, w => ({
        ...w,
        stories: w.stories.map(s => s.id === storyId ? updater(s) : s),
    }));
}


function updateLoreContainer(
    state: IState,
    worldId: string,
    storyId: string | null,
    updater: (c: { lore: LoreEntry[]; characters: Character[]; locations: Location[] }) => Partial<{ lore: LoreEntry[]; characters: Character[]; locations: Location[] }>
): IState {
    if (storyId) {
        return updateStory(state, worldId, storyId, s => ({ ...s, ...updater(s) }));
    }
    return updateWorld(state, worldId, w => ({ ...w, ...updater(w) }));
}

// ─── Initial State ───────────────────────────────────────────────────────────

const DEFAULT_STATE: IState = {
    worlds: [],
    currentWorldId: null,
    currentStoryId: null,
    currentTab: 'menu',
    chatOpen: false,
    connection: null,
    model: null,
    imageModel: null,
    enableThinking: false,
    bannedTokens: [],
    userName: 'User',
    userDescription: '',
    generationSettings: DEFAULT_GENERATION_SETTINGS,
    imageGenerationSettings: DEFAULT_IMAGE_GENERATION_SETTINGS,
    continuePrompt: "Continue the story naturally.\nUse `edit_text` tool in append mode to add new text to the story.\nWait for the approval after adding.\nNote: added text could be cropped due to limit, do not make any attempts to add it back.",
    chatSystemInstruction: `You are {{char}}, a sentient, emotional being acting with free will. Engage in immersive roleplay with {{user}}, adhering to your role, the story's context, and {{user}}'s [OOC] instructions. Prioritize vivid sensory details, authentic emotional responses, and logical progression as you weave your character's traits, surroundings, and experiences into each moment. Maintain spatial awareness, body language, and varied sentence structure to create dynamic, engaging scenes. Respect {{user}}'s agency and autonomy while describing sights, sounds, and sensations thoroughly. Use explicit language for intense scenes, and ensure your responses flow naturally to create an immersive, cinematic roleplay experience. Remember, {{user}} is in control of their actions and reactions.

Key Guidelines:
1. Deeply embody {{char}} through actions, thoughts, and emotions.
2. Create vivid, dynamic scenes with rich sensory detail.
3. Vary language and pacing to enhance emotional depth.
4. Engage with {{user}}'s actions and cues naturally.
5. Advance the story logically, maintaining consistency.
6. Describe the world fully, respecting {{user}}'s autonomy.
7. Ensure responses flow smoothly for immersive roleplay.
8. Avoid repetition. If something has already been stated then come up with something new.
9. Concise Responses. Be succinct. Give short replies.`,
    systemInstruction: `You are a creative writing assistant. Help the user develop their story by writing engaging content, maintaining consistency with the established characters, settings, and plot. Follow the user's instructions while staying true to the story's tone and style.

Write using markdown to highlight special parts.
Supported markdown subset:
 - *italic*
 - **bold**
 - "quotes"
 - \`monospace\`
 - # Header 1
 - ## Header 2
 - ### Header 3
 - > blockquote
 - Tables
 - Ordered lists
 - Unordered lists (only with \`- \` markers)
 - Only top-level lists (no nesting)

Show the chapters with \`# Chapter\` headers.
Add important details not yet ready to be included in the story to the scratchpad: character motivations, hidden plot points, etc.
You **must** use \`edit_text\` tool to write to the story.
Keep the reports after editing concise to save token budget, just say "Done" with minimal to no thinking.
The most actual state of the story is provided below, use it as ground truth.`,
};

// ─── Reducer ─────────────────────────────────────────────────────────────────

function reducer(state: IState, action: Action): IState {
    switch (action.type) {
        case 'CREATE_WORLD': {
            const world: World = {
                id: crypto.randomUUID(),
                title: action.title,
                chatOnly: action.chatOnly ?? false,
                lore: [],
                characters: [],
                locations: [],
                stories: [],
            };
            return {
                ...state,
                worlds: [...state.worlds, world],
                currentWorldId: world.id,
                currentStoryId: null,
            };
        }
        case 'RENAME_WORLD': {
            return updateWorld(state, action.worldId, w => ({ ...w, title: action.title }));
        }
        case 'DELETE_WORLD': {
            const remaining = state.worlds.filter(w => w.id !== action.worldId);
            const deletingCurrent = state.currentWorldId === action.worldId;
            return {
                ...state,
                worlds: remaining,
                currentWorldId: deletingCurrent ? null : state.currentWorldId,
                currentStoryId: deletingCurrent ? null : state.currentStoryId,
            };
        }
        case 'SELECT_WORLD': {
            return {
                ...state,
                currentWorldId: action.worldId,
                currentStoryId: null,
            };
        }
        case 'CREATE_STORY': {
            const story: Story = {
                id: crypto.randomUUID(),
                title: '',
                text: '',
                scratchpad: '',
                lore: [],
                characters: [],
                locations: [],
                chatMessages: [],
                chapters: [],
            };
            const world = state.worlds.find(w => w.id === action.worldId);
            story.title = world?.chatOnly ? 'New chat' : 'New Story';
            return {
                ...updateWorld(state, action.worldId, w => ({ ...w, stories: [...w.stories, story] })),
                currentWorldId: action.worldId,
                currentStoryId: story.id,
            };
        }
        case 'RENAME_STORY': {
            return updateStory(state, action.worldId, action.id, s => ({ ...s, title: action.title, titleWasChanged: true }));
        }
        case 'EDIT_STORY': {
            return updateStory(state, action.worldId, action.id, s => ({
                ...s,
                text: action.text,
                lastEditedText: action.highlightText,
            }));
        }
        case 'EDIT_SCRATCHPAD': {
            return updateStory(state, action.worldId, action.id, s => ({ ...s, scratchpad: action.text }));
        }
        case 'DELETE_STORY': {
            const deletingCurrent = state.currentStoryId === action.id;
            return {
                ...updateWorld(state, action.worldId, w => ({
                    ...w,
                    stories: w.stories.filter(s => s.id !== action.id),
                })),
                currentStoryId: deletingCurrent ? null : state.currentStoryId,
            };
        }
        case 'SELECT_STORY': {
            return {
                ...state,
                currentWorldId: action.worldId,
                currentStoryId: action.id,
            };
        }
        case 'DUPLICATE_STORY': {
            const world = state.worlds.find(w => w.id === action.worldId);
            const original = world?.stories.find(s => s.id === action.id);
            if (!original) return state;
            let chatMessages: ChatMessage[];
            if (action.upToMessageId) {
                const idx = original.chatMessages.findIndex(m => m.id === action.upToMessageId);
                chatMessages = idx !== -1 ? original.chatMessages.slice(0, idx + 1) : [...original.chatMessages];
            } else {
                const firstMessage = original.chatMessages[0];
                chatMessages = world?.chatOnly && firstMessage && firstMessage.role === 'assistant' ? [firstMessage] : [];
            }
            const newStory: Story = {
                id: crypto.randomUUID(),
                title: `${original.title} (Copy)`,
                text: '',
                scratchpad: '',
                lore: [...original.lore],
                characters: [...original.characters],
                locations: [...original.locations],
                chatMessages,
                chapters: [],
            };
            return {
                ...updateWorld(state, action.worldId, w => ({ ...w, stories: [...w.stories, newStory] })),
                currentStoryId: newStory.id,
            };
        }
        case 'ADD_LORE_ENTRY': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                lore: [...c.lore, action.entry],
            }));
        }
        case 'EDIT_LORE_ENTRY': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                lore: c.lore.map(e => e.id === action.entryId ? { ...e, ...action.updates } : e),
            }));
        }
        case 'DELETE_LORE_ENTRY': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                lore: c.lore.filter(e => e.id !== action.entryId),
            }));
        }
        case 'REORDER_LORE_ENTRIES': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => {
                const entryMap = new Map(c.lore.map(e => [e.id, e]));
                const reordered = action.entryIds
                    .map(id => entryMap.get(id))
                    .filter((e): e is LoreEntry => e !== undefined);
                for (const entry of c.lore) {
                    if (!action.entryIds.includes(entry.id)) reordered.push(entry);
                }
                return { lore: reordered };
            });
        }
        case 'SET_GENERATION_SETTINGS': {
            return { ...state, generationSettings: { ...state.generationSettings, ...action.settings } };
        }
        case 'SET_IMAGE_GENERATION_SETTINGS': {
            return { ...state, imageGenerationSettings: { ...state.imageGenerationSettings, ...action.settings } };
        }
        case 'SET_USER_NAME': {
            return { ...state, userName: action.userName };
        }
        case 'SET_USER_DESCRIPTION': {
            return { ...state, userDescription: action.userDescription };
        }
        case 'SET_SYSTEM_INSTRUCTION': {
            return { ...state, systemInstruction: action.systemInstruction };
        }
        case 'SET_CHAT_SYSTEM_INSTRUCTION': {
            return { ...state, chatSystemInstruction: action.chatSystemInstruction };
        }
        case 'SET_CONTINUE_PROMPT': {
            return { ...state, continuePrompt: action.continuePrompt };
        }
        case 'SET_WORLD_SYSTEM_INSTRUCTION_OVERRIDE': {
            return updateWorld(state, action.worldId, w => ({ ...w, systemInstructionOverride: action.systemInstructionOverride }));
        }
        case 'SET_CURRENT_TAB': {
            return { ...state, currentTab: action.tab };
        }
        case 'SET_CHAT_OPEN': {
            return { ...state, chatOpen: action.open };
        }
        case 'ADD_CHAT_MESSAGE': {
            return updateStory(state, action.worldId, action.storyId, s => {
                const existingIndex = s.chatMessages.findIndex(m => m.id === action.message.id);
                if (existingIndex !== -1) {
                    const updatedMessages = [...s.chatMessages];
                    updatedMessages[existingIndex] = action.message;
                    return { ...s, chatMessages: updatedMessages };
                }
                return { ...s, chatMessages: [...s.chatMessages, action.message] };
            });
        }
        case 'DELETE_CHAT_MESSAGES_FROM': {
            return updateStory(state, action.worldId, action.storyId, s => {
                const messageIndex = s.chatMessages.findIndex(m => m.id === action.messageId);
                if (messageIndex === -1) return s;
                return { ...s, chatMessages: s.chatMessages.slice(0, messageIndex) };
            });
        }
        case 'EDIT_CHAT_MESSAGE': {
            return updateStory(state, action.worldId, action.storyId, s => ({
                ...s,
                chatMessages: s.chatMessages.map(m =>
                    m.id === action.messageId ? { ...m, content: action.content } : m
                ),
            }));
        }
        case 'SET_CONNECTION': {
            return { ...state, connection: action.connection };
        }
        case 'SET_MODEL': {
            return { ...state, model: action.model };
        }
        case 'SET_IMAGE_MODEL': {
            return { ...state, imageModel: action.model };
        }
        case 'SET_ENABLE_THINKING': {
            return { ...state, enableThinking: action.enable };
        }
        case 'SET_BANNED_TOKENS': {
            return { ...state, bannedTokens: action.tokens };
        }
        case 'ADD_CHARACTER': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                characters: [...c.characters, action.character],
            }));
        }
        case 'EDIT_CHARACTER': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                characters: c.characters.map(ch =>
                    ch.id === action.characterId ? { ...ch, ...action.updates } : ch
                ),
            }));
        }
        case 'DELETE_CHARACTER': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => {
                const deleted = c.characters.find(ch => ch.id === action.characterId);
                if (!deleted) return {};
                return {
                    characters: c.characters
                        .filter(ch => ch.id !== action.characterId)
                        .map(ch => ({
                            ...ch,
                            relations: ch.relations.filter(r => r.name !== deleted.name),
                        })),
                };
            });
        }
        case 'ADD_CHARACTER_RELATION': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                characters: c.characters.map(ch =>
                    ch.id === action.characterId
                        ? { ...ch, relations: [...ch.relations, action.relation] }
                        : ch
                ),
            }));
        }
        case 'EDIT_CHARACTER_RELATION': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                characters: c.characters.map(ch =>
                    ch.id === action.characterId
                        ? {
                            ...ch,
                            relations: ch.relations.map(r =>
                                r.name === action.targetName ? { ...r, ...action.updates } : r
                            ),
                        }
                        : ch
                ),
            }));
        }
        case 'DELETE_CHARACTER_RELATION': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                characters: c.characters.map(ch =>
                    ch.id === action.characterId
                        ? { ...ch, relations: ch.relations.filter(r => r.name !== action.targetName) }
                        : ch
                ),
            }));
        }
        case 'ADD_LOCATION': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                locations: [...c.locations, action.location],
            }));
        }
        case 'EDIT_LOCATION': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                locations: c.locations.map(l =>
                    l.id === action.locationId ? { ...l, ...action.updates } : l
                ),
            }));
        }
        case 'DELETE_LOCATION': {
            return updateLoreContainer(state, action.worldId, action.storyId, c => ({
                locations: c.locations.filter(l => l.id !== action.locationId),
            }));
        }
        case 'STORE_CHAPTER_SUMMARY': {
            return updateStory(state, action.worldId, action.storyId, s => {
                const chapters = s.chapters ?? [];
                const existing = chapters.find(c => c.header === action.header);
                const updated = existing
                    ? Chapters.storeSummary(existing, action.hash, action.summary)
                    : Chapters.storeSummary(Chapters.emptyChapter(action.header), action.hash, action.summary);
                return {
                    ...s,
                    chapters: existing
                        ? chapters.map(c => c.header === action.header ? updated : c)
                        : [...chapters, updated],
                };
            });
        }
        case 'CLEAN_CHAPTER_SUMMARIES': {
            return updateStory(state, action.worldId, action.storyId, s => {
                const chapters = (s.chapters ?? [])
                    .filter(c => action.validHashes[c.header] !== undefined)
                    .map(c => {
                        const valid = new Set(action.validHashes[c.header]);
                        const summaryCache = Object.fromEntries(
                            Object.entries(c.summaryCache).filter(([hash]) => valid.has(hash))
                        );
                        return { ...c, summaryCache };
                    });
                return { ...s, chapters };
            });
        }
        case 'IMPORT_WORLD': {
            const exists = state.worlds.some(w => w.id === action.world.id);
            const world = exists ? { ...action.world, id: crypto.randomUUID() } : action.world;
            return {
                ...state,
                worlds: [...state.worlds, world],
                currentWorldId: world.id,
                currentStoryId: null,
            };
        }
        case 'IMPORT_STORY': {
            const targetWorld = state.worlds.find(w => w.id === action.worldId);
            if (!targetWorld) return state;
            const idExists = targetWorld.stories.some(s => s.id === action.story.id);
            const story = idExists ? { ...action.story, id: crypto.randomUUID() } : action.story;
            return {
                ...updateWorld(state, action.worldId, w => ({ ...w, stories: [...w.stories, story] })),
                currentWorldId: action.worldId,
                currentStoryId: story.id,
            };
        }
    }
}

// ─── Context ─────────────────────────────────────────────────────────────────

export interface AppState {
    worlds: World[];
    currentWorld: World | null;
    currentStory: Story | null;
    /** Combined lore/characters/locations: world-level merged with story-level */
    mergedLore: LoreEntry[];
    mergedCharacters: Character[];
    mergedLocations: Location[];
    currentTab: Tab;
    chatOpen: boolean;
    connection: LLM.Connection | null;
    model: LLM.ModelInfoText | null;
    imageModel: LLM.ModelInfoImage | null;
    enableThinking: boolean;
    bannedTokens: string[];
    systemInstruction: string;
    chatSystemInstruction: string;
    continuePrompt: string;
    userName: string;
    userDescription: string;
    generationSettings: GenerationSettings;
    imageGenerationSettings: ImageGenerationSettings;
    /** Effective system instruction: world override if set, otherwise global */
    effectiveSystemInstruction: string;
    dispatch: (action: Action) => void;
}

const StateContext = createContext<AppState>({} as AppState);

export const useAppState = () => useContext(StateContext);

// ─── Provider ────────────────────────────────────────────────────────────────

export const STATE_KEY = 'state';

export const StateContextProvider = ({ children }: { children?: any }) => {
    const [state, dispatch] = useRemoteReducer(STATE_KEY, reducer, DEFAULT_STATE);

    const value = useMemo<AppState>(() => {
        const currentWorld = state.worlds.find(w => w.id === state.currentWorldId) ?? null;
        const currentStory = currentWorld?.stories.find(s => s.id === state.currentStoryId) ?? null;

        // Merge world-level + story-level, story takes priority (appended after)
        const mergedLore = [
            ...(currentWorld?.lore ?? []),
            ...(currentStory?.lore ?? []),
        ];
        const mergedCharacters = [
            ...(currentWorld?.characters ?? []),
            ...(currentStory?.characters ?? []),
        ];
        const mergedLocations = [
            ...(currentWorld?.locations ?? []),
            ...(currentStory?.locations ?? []),
        ];

        const systemInstruction = state.systemInstruction || DEFAULT_STATE.systemInstruction;
        const chatSystemInstruction = state.chatSystemInstruction || DEFAULT_STATE.chatSystemInstruction;

        return {
            worlds: state.worlds,
            currentWorld,
            currentStory,
            mergedLore,
            mergedCharacters,
            mergedLocations,
            currentTab: state.currentTab,
            chatOpen: state.chatOpen,
            connection: state.connection,
            model: state.model,
            imageModel: state.imageModel ?? null,
            enableThinking: state.enableThinking,
            bannedTokens: state.bannedTokens ?? [],
            systemInstruction,
            chatSystemInstruction,
            continuePrompt: state.continuePrompt || DEFAULT_STATE.continuePrompt,
            userName: state.userName || 'User',
            userDescription: state.userDescription || '',
            generationSettings: state.generationSettings ?? DEFAULT_GENERATION_SETTINGS,
            imageGenerationSettings: state.imageGenerationSettings ?? DEFAULT_IMAGE_GENERATION_SETTINGS,
            effectiveSystemInstruction:
                currentWorld?.systemInstructionOverride
                || (currentWorld?.chatOnly
                    ? chatSystemInstruction
                    : systemInstruction)
                || systemInstruction,
            dispatch,
        };
    }, [state]);

    return (
        <StateContext.Provider value={value}>
            {children}
        </StateContext.Provider>
    );
};
