ai-text-adventure/backend/server.js

const http = require('http');
const fs = require('fs');
const path = require('path');
const fetch = require('node-fetch');

const PORT = 3030;
const STATE_FILE = path.join(__dirname, 'data', 'story_state.json');
const API_URL = 'https://open-webui.spacek.blue/api/chat/completions';
const API_KEY = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjAzNmEwYjQyLWNmMDktNDVmNy05MWUzLTBkYjI2YmE1MDRlNSIsImp0aSI6ImY0ZmM0OTM2LTliOTktNDU4Ny05MjM3LTY1OWJkN2UzYTYyOSIsImlhdCI6MTc3NzkzMTAyNX0.3E6pc8R9kVHIG2sQXH0pPADJkhbwZVw1QVniqVVYwcU';
const MODEL = 'gemma4:26b'; // Default model for generation and analysis

// Prompts moved from frontend to backend
const PROMPTS = {
    updateWorldState: (history) => `Analyze the following recent history of an interactive fiction story. 
Based on the events, update the world state. 
Return ONLY a JSON object with the following structure:
{
  "lore": "updated or expanded lore",
  "characters": [{"name": "name", "description": "description", "possessions": ["item1", "item2"]}],
  "plot_plans": [{"description": "plot point", "relevance_timer": 5}],
  "history_summary": "a brief summary of what just happened"
}

History:
${history.slice(-5).join('\n')}

Ensure the updates are consistent with the existing lore and characters. If no new significant details are found, return the existing lore and characters but updated with any new developments.`,

    suggest: (history) => `Based on the following recent history of an interactive fiction story, suggest three short, distinct, and interesting actions the player could take. 
Return ONLY a JSON array of strings.
Example: ["Open the heavy door", "Search the desk", "Call out into the darkness"]

History:
${history.slice(-5).join('\n')}`,

    generate: (state, userAction) => `You are an expert storyteller. Your goal is to weave a deeply immersive, long-form narrative that brings the world to life, regardless of the genre.

Current World Context:
Lore: ${state.lore || "None"}
Characters: ${ (state.characters || []).map(c => c.name + ": " + c.description).join(", ") || "None" }
Plot Plans: ${ (state.plot_plans || []).map(p => p.description + " (reras: " + p.relevance_timer + ")").join("\n") || "None" }

Recent History:
${(state.history || []).slice(-15).join("\n")}

Your Mandate:
1. **Immersive Detail**: Provide rich, sensory-heavy descriptions. Focus on sounds, smells, textures, and the weight of the atmosphere. Do not rush the story; let the moments linger.
2. **Long-form Narrative**: Your responses should be substantial and detailed, painting a complete picture of the scene and the impact of the user's actions.
3. **World Reactivity & Consequence**: Every user action must have a tangible, realistic consequence within the established lore and plot. The player's input is an *attempt* at action, not an absolute truth. You decide if the action succeeds, fails, or has unforeseen side effects. The player is a character in this world, subject to its dangers and limitations.
4. **Character Depth**: When characters are present, imbue them with distinct voices, subtle mannerisms, and hidden motivations.
5. **Avoid AI Tropes**: Do not use cliché narrator phrases like "As the adventure unfolds," "The air was thick with...", or "A sense of [emotion] washed oly you." Avoid summarizing the user's actions back to them. Do not break the fourth wall.
6. **Maintain Agency**: NEVER speak, think, or act for the player character. The player's agency is sacred.
7. **Narrative Flow**: Use the plot plans to guide the unfolding drama, but allow the user's unexpected actions to organically shape the journey.

User Action Attempt: ${userAction}`,

    generateWorld: (suggestions) => `You are an expert world-builder and storyteller. 
The user wants to start a new interactive fiction adventure with the following themes/suggestions: "${suggestions}".

Your task is to create a comprehensive and detailed foundation for this world. 
Return ONLY a JSON object with the following structure:
{
  "lore": "A rich, detailed description of the world's setting, history, and magic/technology systems.",
  "characters": [{"name": "name", "description": "description", "possessions": ["item1", "item2"]}],
  "plot_plans": [{"description": "an initial plot point to kick off the story", "relevance_timer": 10}],
  "intro": "A beautiful, immersive, and long-form introduction to the story that sets the scene and places the player in the starting location. This should be the first piece of text the player reads."
}

Ensure the lore is deep and the characters feel alive. The intro should be evocative and atmospheric, making the player want to take their first action immediately.`

};

let currentStatus = 'idle';

// Helper to read state
function readState() {
    try {
        if (fs.existsSync(STATE_FILE)) {
            const data = fs.readFileSync(STATE_FILE, 'utf8');
            return JSON.parse(data);
        }
    } catch (err) {
        console.error('Error reading state:', err);
    }
    return { 
        lore: '', 
        characters: [], 
        plot_plans: [], 
        history: [],
        world_details: {} // For any other world properties
    };
}

// Helper to write state
function writeState(state) {
    try {
        fs.writeFileSync(STATE_FILE, JSON.stringify(state, null, 2));
    } catch (err) {
        console.error('Error writing state:', err);
    }
}

// New helper to update world state using AI analysis
async function updateWorldState(history) {
    currentStatus = 'updating world state';
    console.log('--- World State Update Started ---');
    console.log('History length:', history.length);
    const currentState = readState();
    const analysisPrompt = PROMPTS.updateWorldState(history);

    try {
        console.log('Sending request to OpenAI-compatible API at:', API_URL);
        const response = await fetch(API_URL, {
            method: 'POST',
            headers: { 
                'Content-Type': 'application/json',
                'Authorization': `Bearer ${API_KEY}`
            },
            body: JSON.stringify({
                model: MODEL,
                messages: [{ role: 'user', content: analysisPrompt }],
                stream: false,
                response_format: { type: 'json_object' }
            })
        });

        console.log('API response received. Parsing JSON...');

        // THIS SOMETIMES FAILS BECAUSE THE JSON WAS INVALID
        const data = await response.json();
        
        // OpenAI-compatible response structure: data.choices[0].message.content
        let content = '';
        if (data.choices && data.choices[0] && data.choices[0].message && data.choices[0].message.content) {
            content = data.choices[0].message.content;
        } else {
            throw new Error('Unexpected API response structure: ' + JSON.stringify(data));
        }

        // Robustly extract JSON object from the response, handling potential markdown or preamble
        let updates;
        try {
            const startIdx = content.indexOf('{');
            const endIdx = content.lastIndexOf('}');
            if (startIdx !== -1 && endIdx !== -1) {
                const jsonStr = content.substring(startIdx, endIdx + 1);
                updates = JSON.parse(jsonStr);
            } else {
                throw new Error('No JSON object found in response content');
            }
        } catch (err) {
            console.error('Failed to parse updates JSON:', err);
            throw err;
        }

        const newState = {
            ...currentState,
            lore: updates.lore || currentState.lore,
            characters: updates.characters || currentState.characters,
            plot_plans: updates.plot_plans || currentState.plot_plans,
            // We keep the summary if needed for something else
        };
        writeState(newState);
        console.log('--- World State Update Completed ---');
    } catch (err) {
        console.error('Error updating world state:', err);
        currentStatus = 'error updating world state';
    } finally {
        if (currentStatus !== 'error updating world state') {
            currentStatus = 'idle';
        }
    }
}

const server = http.createServer(async (req, res) => {
    // CORS Headers
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
    // Allow client to listen for Server-Sent Events
    res.setHeader('Access-Control-Allow-Credentials', 'token');
    res.setHeader('Access-Control-Allow-Credentials', 'true');

    const url = new URL(req.url, `http://${req.headers.host}`);

    if (url.pathname === '/favicon.ico') {
        res.writeHead(204);
        res.end();
        return;
    }

    if (req.method === 'OPTIONS') {
        res.writeHead(204);
        res.end();
        return;
    }

    if (url.pathname === '/api/state' && req.method === 'GET') {
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify(readState()));
    } 
    else if (url.pathname === '/api/status' && req.method === 'GET') {
        res.writeHead(200, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ status: currentStatus }));
    }
    else if (url.pathname === '/api/state' && req.method === 'POST') {
        let body = '';
        req.on('data', chunk => { body += chunk; });
        req.on('end', () => {
            try {
                const newState = JSON.parse(body);
                writeState(newState);
                res.writeHead(200, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ message: 'State updated' }));
            } catch (err) {
                res.writeHead(400, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'Invalid JSON' }));
            }
        });
    } 
    else if (url.pathname === '/api/suggest' && req.method === 'POST') {
        let body = '';
        req.on('data', chunk => { body += chunk; });
        req.on('end', async () => {
            try {
                const { history, model } = JSON.parse(body);
                const analysisPrompt = PROMPTS.suggest(history);

                const response = await fetch(API_URL, {
                    method: 'POST',
                    headers: { 
                        'Content-Type': 'application/json',
                        'Authorization': `Bearer ${API_KEY}`
                    },
                    body: JSON.stringify({
                        model: model || MODEL,
                        messages: [{ role: 'user', content: analysisPrompt }],
                        stream: false,
                        response_format: { type: 'json_object' }
                    })
                });

                const data = await response.json();
                let content = '';
                if (data.choices && data.choices[0] && data.choices[0].message && data.choices[0].message.content) {
                    content = data.choices[0].message.content;
                }

                // Extract JSON array from response
                let suggestions = [];
                const startIdx = content.indexOf('[');
                const endIdx = content.lastIndexOf(']');
                if (startIdx !== -1 && endIdx !== -1) {
                    suggestions = JSON.parse(content.substring(startIdx, endIdx + 1));
                }

                res.writeHead(200, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ suggestions }));
            } catch (err) {
                console.error('Error in /api/suggest:', err);
                res.writeHead(500, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'Internal Server Error' }));
            }
        });
    }
    else if (url.pathname === '/api/generate' && req.method === 'POST') {
        currentStatus = 'generating story';
        let body = '';
        req.on('data', chunk => { body += chunk; });
        req.on('end', async () => {
            try {
                const { prompt: userAction, model, stream } = JSON.parse(body);
                
                // Construct the full prompt on the backend
                const currentState = readState();
                const systemPrompt = PROMPTS.generate(currentState, userAction);

                const apiOptions = {
                    method: 'POST',
                    headers: { 
                        'Content-Type': 'application/json',
                        'Authorization': `Bearer ${API_KEY}`
                    },
                    body: JSON.stringify({
                        model: model || MODEL,
                        messages: [{ role: 'user', content: systemPrompt }],
                        stream: stream !== undefined ? stream : false
                    })
                };

                if (stream) {
                    console.log('Starting stream to client...');
                    const apiOptions = {
                        method: 'POST',
                        headers: { 
                            'Content-Type': 'application/json',
                            'Authorization': `Bearer ${API_KEY}`
                        },
                        body: JSON.stringify({
                            model: model || MODEL,
                            messages: [{ role: 'user', content: systemPrompt }],
                            stream: true
                        })
                    };

                    const response = await fetch(API_URL, apiOptions);
                    res.writeHead(200, { 
                        'Content-Type': 'text/event-stream',
                        'Cache-Control': 'no-cache',
                        'Connection': 'keep-alive'
                    });

                    let accumulatedResponse = "";
                    response.body.on('data', (chunk) => {
                        const lines = chunk.toString().split('\n');
                        for (const line of lines) {
                            if (!line.trim() || line.trim() === 'data: [DONE]') continue;
                            
                            try {
                               // Remove 'data: ' prefix
                               const jsonStr = line.replace(/^data: /, '');
                               const json = JSON.parse(jsonStr);
                               const content = json.choices[0].delta.content || '';
                               if (content) {
                                   accumulatedResponse += content;
                                   res.write(JSON.stringify({ response: content }) + '\n');
                               }
                            } catch (err) {
                               // Handle parsing errors for partial or malformed chunks
                            }
                        }
                    });

                    response.body.on('end', async () => {
                        console.log('Stream ended. Updating history and triggering background world state update...');
                        
                        const updatedHistory = [...currentState.history, `User: ${userAction}`, `AI: ${accumulatedResponse}`];
                        
                        const newState = {
                            ...currentState,
                            history: updatedHistory
                        };
                        writeState(newState);

                        updateWorldState(updatedHistory)
                            .then(summary => {
                                if (summary) {
                                    console.log('Background update summary:', summary);
                               }
                            })
                            .catch(err => {
                               console.error('Error in background world state update:', err);
                            });
                        res.end();
                    });
                } else {
                    const apiOptions = {
                        method: 'POST',
                        headers: { 
                            'Content-Type': 'application/json',
                            'Authorization': `Bearer ${API_KEY}`
                        },
                        body: JSON.stringify({
                            model: model || MODEL,
                            messages: [{ role: 'user', content: systemPrompt }],
                            stream: false
                        })
                    };

                    console.log('Sending request to OpenAI-compatible API...');
                    const response = await fetch(API_URL, apiOptions);
                    const data = await response.json();
                    
                    let content = '';
                    if (data.choices && data.choices[0] && data.choices[0].message && data.choices[0].message.content) {
                        content = data.choices[0].message.content;
                    } else {
                        throw new Error('Unexpected API response structure: ' + JSON.stringify(data));
                    }

                    const ollamaFormatChunk = JSON.stringify({ response: content });
                    res.write(ollamaFormatChunk);

                    const updatedHistory = [...currentState.history, `User: ${userAction}`, `AI: ${content}`];
                    
                    const newState = {
                        ...currentState,
                        history: updatedHistory
                    };
                    writeState(newState);

                    updateWorldState(updatedHistory)
                        .then(summary => {
                            if (summary) {
                               console.log('Background update summary:', summary);
                            }
                        })
                        .catch(err => {
                            console.error('Error in background world state update:', err);
                        });

                    res.end();
                }
            } catch (err) {
                currentStatus = 'idle';
                console.error('Error generating response:', err);
                res.writeHead(500, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'Generation failed' }));
            }
        });
    } 
    else if (url.pathname === '/api/generate-world' && req.method === 'POST') {
        currentStatus = 'generating world';
        let body = '';
        req.on('data', chunk => { body += chunk; });
        req.on('end', async () => {
            try {
                const { suggestions, model } = JSON.parse(body);
                const analysisPrompt = PROMPTS.generateWorld(suggestions);

                const response = await fetch(API_URL, {
                    method: 'POST',
                    headers: { 
                        'Content-Type': 'application/json',
                        'Authorization': `Bearer ${API_KEY}`
                    },
                    body: JSON.stringify({
                        model: model || MODEL,
                        messages: [{ role: 'user', content: analysisPrompt }],
                        stream: false,
                        response_format: { type: 'json_object' }
                    })
                });

                const data = await response.json();
                let content = '';
                if (data.choices && data.choices[0] && data.choices[0].message && data.choices[0].message.content) {
                    content = data.choices[0].message.content;
                }

                let worldData;
                const startIdx = content.indexOf('{');
                const endIdx = content.lastIndexOf('}');
                if (startIdx !== -1 && endIdx !== -1) {
                    worldData = JSON.parse(content.substring(startIdx, endIdx + 1));
                } else {
                    throw new Error('No JSON object found in response content');
                }

                const intro = worldData.intro || "";
                const newState = {
                    lore: worldData.lore || '',
                    characters: worldData.characters || [],
                    plot_plans: worldData.plot_plans || [],
                    history: [ `AI: ${intro}` ]
                };
                writeState(newState);

                // For world generation, we don't stream, we just send the intro as one chunk
                const responseChunk = JSON.stringify({ response: intro });
                res.write(responseChunk);
                res.end();

            } catch (err) {
                console.error('Error in /api/generate-world:', err);
                res.writeHead(500, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'World generation failed' }));
            } finally {
                currentStatus = 'idle';
            }
        });
    }
    else if (url.pathname === '/api/state' && req.method === 'POST') {
        let body = '';
        req.on('data', chunk => { body += chunk; });
        req.on('end', () => {
            try {
                const newState = JSON.parse(body);
                writeState(newState);
                res.writeHead(200, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ message: 'State updated' }));
            } catch (err) {
                res.writeHead(400, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'Invalid JSON' }));
            }
        });
    }
    else {
        // Serve static files from the frontend directory
        const filePath = path.join(__dirname, '..', 'frontend', url.pathname === '/' ? 'index.html' : url.pathname);
        fs.access(filePath, fs.constants.F_OK, (err) => {
            if (err) {
                res.writeHead(404);
                res.end('File not found');
                return;
            }

            const stream = fs.createReadStream(filePath);
            
            // Determine content type
            const ext = path.extname(filePath);
            const mimeTypes = {
                '.html': 'text/html',
                '.js': 'text/javascript',
                '.css': 'text/css',
                '.json': 'application/json',
                '.png': 'image/png',
                '.jpg': 'image/jpg',
                '.gif': 'image/gif'
            };
            const contentType = mimeTypes[ext] || 'application/octet-stream';

            res.writeHead(200, { 'Content-Type': contentType });
            stream.pipe(res);
        });
    }
});

server.listen(PORT, () => {
    console.log(`Server running at http://localhost:${PORT}/`);
});