/**
 * State Manager - Manages application state
 */

export class StateManager {
    constructor() {
        this.state = {};
        this.listeners = {};
        
        // Load persisted state
        this.loadPersistedState();
    }
    
    get(key) {
        return this.state[key];
    }
    
    set(key, value) {
        const oldValue = this.state[key];
        this.state[key] = value;
        
        // Persist certain keys
        if (this.shouldPersist(key)) {
            this.persistState(key, value);
        }
        
        // Notify listeners
        this.notifyListeners(key, value, oldValue);
    }
    
    remove(key) {
        const oldValue = this.state[key];
        delete this.state[key];
        
        // Remove from localStorage
        if (this.shouldPersist(key)) {
            localStorage.removeItem(`clean-tracks-${key}`);
        }
        
        // Notify listeners
        this.notifyListeners(key, undefined, oldValue);
    }
    
    clear(keys = null) {
        if (keys) {
            keys.forEach(key => this.remove(key));
        } else {
            // Clear all state
            Object.keys(this.state).forEach(key => this.remove(key));
        }
    }
    
    // State persistence
    shouldPersist(key) {
        const persistedKeys = [
            'userSettings',
            'theme',
            'language',
            'defaultWordList',
            'defaultCensorMethod',
            'defaultWhisperModel',
            // Onboarding-related state
            'hasCompletedOnboarding',
            'onboardingProgress',
            'onboardingMilestones',
            'onboardingVersion',
            'onboardingSkipped',
            'onboardingCompletedAt'
        ];
        
        return persistedKeys.includes(key);
    }
    
    persistState(key, value) {
        try {
            localStorage.setItem(`clean-tracks-${key}`, JSON.stringify(value));
        } catch (error) {
            console.error('Error persisting state:', error);
        }
    }
    
    loadPersistedState() {
        const persistedKeys = [
            'userSettings',
            'theme',
            'language',
            'defaultWordList',
            'defaultCensorMethod',
            'defaultWhisperModel',
            // Onboarding-related state
            'hasCompletedOnboarding',
            'onboardingProgress',
            'onboardingMilestones',
            'onboardingVersion',
            'onboardingSkipped',
            'onboardingCompletedAt'
        ];
        
        persistedKeys.forEach(key => {
            try {
                const value = localStorage.getItem(`clean-tracks-${key}`);
                if (value) {
                    this.state[key] = JSON.parse(value);
                }
            } catch (error) {
                console.error(`Error loading persisted state for ${key}:`, error);
            }
        });
    }
    
    // State listeners
    subscribe(key, listener) {
        if (!this.listeners[key]) {
            this.listeners[key] = [];
        }
        
        this.listeners[key].push(listener);
        
        // Return unsubscribe function
        return () => {
            this.unsubscribe(key, listener);
        };
    }
    
    unsubscribe(key, listener) {
        if (this.listeners[key]) {
            this.listeners[key] = this.listeners[key].filter(l => l !== listener);
        }
    }
    
    notifyListeners(key, newValue, oldValue) {
        if (this.listeners[key]) {
            this.listeners[key].forEach(listener => {
                try {
                    listener(newValue, oldValue, key);
                } catch (error) {
                    console.error(`Error in state listener for ${key}:`, error);
                }
            });
        }
        
        // Notify global listeners
        if (this.listeners['*']) {
            this.listeners['*'].forEach(listener => {
                try {
                    listener(key, newValue, oldValue);
                } catch (error) {
                    console.error('Error in global state listener:', error);
                }
            });
        }
    }
    
    // Computed values
    compute(key, computeFn) {
        Object.defineProperty(this.state, key, {
            get: computeFn,
            enumerable: true,
            configurable: true
        });
    }
    
    // State snapshots
    getSnapshot() {
        return JSON.parse(JSON.stringify(this.state));
    }
    
    restoreSnapshot(snapshot) {
        this.state = JSON.parse(JSON.stringify(snapshot));
        
        // Notify all listeners
        Object.keys(this.state).forEach(key => {
            this.notifyListeners(key, this.state[key], undefined);
        });
    }
    
    // Debugging
    debug() {
        console.group('State Manager Debug');
        console.log('Current State:', this.state);
        console.log('Listeners:', Object.keys(this.listeners).map(key => ({
            key,
            count: this.listeners[key].length
        })));
        console.groupEnd();
    }
}