export class WaterTracker {
    constructor(containerId) {
        this.container = document.getElementById(containerId);
        this.state = {
            current: 0,
            goal: 3000, // mL
            bottleSize: 500, // mL
        };
        this.STORAGE_KEY = 'hydroflux_data';
        this.loadState();
        this.render();
        this.attachEvents();
        this.updateUI();
    }

    loadState() {
        const saved = localStorage.getItem(this.STORAGE_KEY);
        if (saved) {
            const parsed = JSON.parse(saved);
            this.state = { ...this.state, ...parsed };
        }
    }

    saveState() {
        localStorage.setItem(this.STORAGE_KEY, JSON.stringify(this.state));
        this.updateUI();
    }

    addWater() {
        this.state.current += this.state.bottleSize;
        this.saveState();
        if (navigator.vibrate) navigator.vibrate(50);
    }

    removeWater() {
        this.state.current = Math.max(0, this.state.current - this.state.bottleSize);
        this.saveState();
        if (navigator.vibrate) navigator.vibrate(50);
    }

    setBottleSize(size) {
        if (!size || size <= 0) return;
        this.state.bottleSize = size;
        this.saveState();
    }

    getPercentage() {
        return Math.min(100, Math.max(0, (this.state.current / this.state.goal) * 100));
    }

    updateUI() {
        // Update Text
        const currentEl = this.container.querySelector('.water-count');
        const percentageEl = this.container.querySelector('.water-percentage');

        if (currentEl) currentEl.textContent = `${this.state.current} / ${this.state.goal} mL`;
        if (percentageEl) percentageEl.textContent = `${Math.round(this.getPercentage())}%`;

        // Update Wave Animation Height
        const wave = this.container.querySelector('.wave');
        if (wave) {
            wave.style.top = `${100 - this.getPercentage()}%`;
        }
    }

    render() {
        this.container.innerHTML = `
            <div class="water-tracker-container">
                <!-- Circular Progress -->
                <div class="circle-container">
                    <div class="water-circle">
                        <div class="wave"></div>
                        <div class="circle-content">
                            <span class="water-percentage">0%</span>
                            <span class="water-label">HYDRATION</span>
                        </div>
                    </div>
                </div>

                <!-- Stats Display -->
                <div class="stats-row">
                    <span class="water-count">0 / 3000 mL</span>
                </div>

                <!-- Controls -->
                <div class="controls-area">
                    <div class="bottle-selector">
                        <label>Bottle (mL):</label>
                        <input type="number" id="bottle-size-input" value="${this.state.bottleSize}" min="1" max="5000">
                    </div>

                    <div class="action-buttons">
                        <button id="remove-water-btn" class="icon-btn secondary" aria-label="Remove Drink">
                            <svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                                <path d="M5 12h14"/>
                            </svg>
                        </button>

                        <button id="add-water-btn" class="glow-btn">
                            <svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                                <path d="M12 5v14M5 12h14"/>
                            </svg>
                            DRINK
                        </button>

                        <!-- Notification Toggle -->
                        <button id="notify-btn" class="icon-btn" title="Enable Reminders">
                            <svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                                <path d="M18 8A6 6 0 0 0 6 8c0 7-3 9-3 9h18s-3-2-3-9"></path>
                                <path d="M13.73 21a2 2 0 0 1-3.46 0"></path>
                            </svg>
                        </button>
                    </div>
                </div>
            </div>
        `;

        this.checkNotificationStatus();
    }

    attachEvents() {
        this.container.querySelector('#add-water-btn').addEventListener('click', () => {
            this.addWater();
        });

        this.container.querySelector('#remove-water-btn').addEventListener('click', () => {
            this.removeWater();
        });

        this.container.querySelector('#notify-btn').addEventListener('click', (e) => {
            this.toggleNotifications(e.currentTarget);
        });

        const input = this.container.querySelector('#bottle-size-input');
        input.addEventListener('change', (e) => {
            this.setBottleSize(parseInt(e.target.value));
        });
    }

    // --- Notification Logic ---

    toggleNotifications(btn) {
        if (!("Notification" in window)) {
            alert("This browser does not support desktop notifications");
            return;
        }

        if (Notification.permission === "granted") {
            alert("Reminders are active! We'll check every hour.");
        } else if (Notification.permission !== "denied") {
            Notification.requestPermission().then(permission => {
                if (permission === "granted") {
                    this.startReminderLoop();
                    btn.style.color = "var(--primary-cyan)";
                    new Notification("HydroFlux", { body: "Smart Hydration Reminders Enabled!" });
                }
            });
        }
    }

    checkNotificationStatus() {
        if (Notification.permission === "granted") {
            const btn = this.container.querySelector('#notify-btn');
            if (btn) btn.style.color = "var(--primary-cyan)";
            this.startReminderLoop();
        }
    }

    startReminderLoop() {
        // Clear existing to avoid duplicates
        if (this.reminderInterval) clearInterval(this.reminderInterval);

        // Check every minute if it's been > 1 hour since last drink
        this.reminderInterval = setInterval(() => {
            // Pseudo-logic check since we don't store timestamp in this simple version yet
            // In a real app, you'd check this.state.lastDrinkTime
            new Notification("HydroFlux Needs You", {
                body: "Remember to drink water!",
                icon: "/icon.png"
            });
        }, 3600000); // 1 Hour
    }
}