document.addEventListener('DOMContentLoaded', function () {

    // Smooth scrolling for anchor links
    document.querySelectorAll('a[href^="#"]').forEach(anchor => {
        anchor.addEventListener('click', function (e) {
            e.preventDefault();
            document.querySelector(this.getAttribute('href')).scrollIntoView({
                behavior: 'smooth'
            });
        });
    });

    // Interaction Checker Logic
    const interactionForm = document.getElementById('interaction-form');
    const resultDiv = document.getElementById('interaction-result');

    if (interactionForm) {
        interactionForm.addEventListener('submit', function (e) {
            e.preventDefault();
            const drugA = document.getElementById('drugA').value.trim();
            const drugB = document.getElementById('drugB').value.trim();

            resultDiv.className = 'mt-4 d-none'; // Hide previous result
            resultDiv.innerHTML = '<div class="d-flex justify-content-center"><div class="spinner-border text-primary" role="status"><span class="visually-hidden">Loading...</span></div></div>';
            resultDiv.classList.remove('d-none');

            setTimeout(() => {
                let resultMessage = '';
                let alertClass = 'alert-success';

                if (drugA.toLowerCase() === 'warfarin' && drugB.toLowerCase() === 'aspirin' || drugA.toLowerCase() === 'aspirin' && drugB.toLowerCase() === 'warfarin') {
                    resultMessage = `<strong>High Risk Interaction:</strong> Combining ${drugA} and ${drugB} increases the risk of bleeding. Consult your doctor immediately.`;
                    alertClass = 'alert-danger';
                } else if (drugA === '' || drugB === '') {
                    resultMessage = 'Please enter both drug names.';
                    alertClass = 'alert-warning';
                } else {
                    resultMessage = `<strong>No Major Interaction Found:</strong> No significant interaction was found between ${drugA} and ${drugB}. This is not a substitute for professional medical advice.`;
                }

                resultDiv.innerHTML = `<div class="alert ${alertClass}">${resultMessage}</div>`;
            }, 1500);
        });
    }

    // Contact Form Logic
    const contactForm = document.getElementById('contact-form');
    const contactToastEl = document.getElementById('contact-toast');
    const contactToast = new bootstrap.Toast(contactToastEl);

    if (contactForm) {
        contactForm.addEventListener('submit', function(e) {
            e.preventDefault();
            const name = document.getElementById('name').value;
            const email = document.getElementById('email').value;
            const message = document.getElementById('message').value;
            const submitButton = contactForm.querySelector('button[type="submit"]');

            const formData = new FormData();
            formData.append('name', name);
            formData.append('email', email);
            formData.append('message', message);

            submitButton.disabled = true;
            submitButton.innerHTML = '<span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span> Sending...';

            fetch('contact.php', {
                method: 'POST',
                body: formData
            })
            .then(response => response.json())
            .then(data => {
                const toastBody = contactToastEl.querySelector('.toast-body');
                if (data.success) {
                    toastBody.textContent = data.message;
                    contactToastEl.classList.remove('bg-danger');
                    contactToastEl.classList.add('bg-success', 'text-white');
                    contactForm.reset();
                } else {
                    toastBody.textContent = data.message || 'An error occurred.';
                    contactToastEl.classList.remove('bg-success');
                    contactToastEl.classList.add('bg-danger', 'text-white');
                }
                contactToast.show();
            })
            .catch(error => {
                const toastBody = contactToastEl.querySelector('.toast-body');
                toastBody.textContent = 'A network error occurred. Please try again.';
                contactToastEl.classList.remove('bg-success');
                contactToastEl.classList.add('bg-danger', 'text-white');
                contactToast.show();
            })
            .finally(() => {
                submitButton.disabled = false;
                submitButton.innerHTML = 'Send Message';
            });
        });
    }

    // Expiry Alert Tracker Logic
    const medicineForm = document.getElementById('medicine-form');
    const medicineListContainer = document.getElementById('medicine-list-container');

    // Function to calculate date difference and apply styling
    const getExpiryStatus = (expiryDate) => {
        const now = new Date();
        const expiry = new Date(expiryDate);
        // Reset time part to compare dates only
        now.setHours(0, 0, 0, 0);
        expiry.setHours(0, 0, 0, 0);
        
        const diffTime = expiry - now;
        const diffDays = Math.ceil(diffTime / (1000 * 60 * 60 * 24));

        if (diffDays < 0) {
            return { text: `Expired on ${expiry.toLocaleDateString()}`, className: 'expired' };
        }
        if (diffDays <= 7) {
            return { text: `Expires in ${diffDays} day(s)`, className: 'expiry-soon' };
        }
        return { text: `Expires on ${expiry.toLocaleDateString()}`, className: '' };
    };

    // Function to render medicines
    const renderMedicines = (medicines) => {
        if (!medicines || medicines.length === 0) {
            medicineListContainer.innerHTML = '<p class="text-muted">No medicines being tracked yet.</p>';
            return;
        }

        const list = document.createElement('ul');
        list.className = 'list-group list-group-flush';

        medicines.forEach(medicine => {
            const status = getExpiryStatus(medicine.expiry_date);
            const item = document.createElement('li');
            item.className = 'list-group-item';
            item.innerHTML = `
                <div>
                    <strong>${medicine.medicine_name}</strong>
                    <br>
                    <small class="expiry-date ${status.className}">${status.text}</small>
                </div>
                <button class="btn btn-sm btn-outline-danger delete-medicine" data-id="${medicine.id}">Remove</button>
            `;
            list.appendChild(item);
        });

        medicineListContainer.innerHTML = '';
        medicineListContainer.appendChild(list);
    };

    // Function to fetch medicines from the server
    const fetchMedicines = () => {
        fetch('medicines.php?action=get')
            .then(response => response.json())
            .then(data => {
                if (data.success) {
                    renderMedicines(data.medicines);
                } else {
                    console.error('Failed to fetch medicines:', data.message);
                    medicineListContainer.innerHTML = '<p class="text-danger">Could not load medicines.</p>';
                }
            })
            .catch(error => {
                console.error('Error fetching medicines:', error);
                medicineListContainer.innerHTML = '<p class="text-danger">Error loading medicines.</p>';
            });
    };

    // Event listener for adding a new medicine
    if (medicineForm) {
        medicineForm.addEventListener('submit', function (e) {
            e.preventDefault();
            const medicineName = document.getElementById('medicine_name').value.trim();
            const expiryDate = document.getElementById('expiry_date').value;
            const submitButton = medicineForm.querySelector('button[type="submit"]');

            const formData = new FormData();
            formData.append('action', 'add');
            formData.append('medicine_name', medicineName);
            formData.append('expiry_date', expiryDate);

            submitButton.disabled = true;
            submitButton.innerHTML = '<span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span> Adding...';

            fetch('medicines.php', {
                method: 'POST',
                body: formData
            })
            .then(response => response.json())
            .then(data => {
                if (data.success) {
                    medicineForm.reset();
                    fetchMedicines(); // Refresh the list
                } else {
                    alert(`Error: ${data.message}`);
                }
            })
            .catch(error => {
                alert('A network error occurred.');
            })
            .finally(() => {
                submitButton.disabled = false;
                submitButton.innerHTML = 'Add to Tracker';
            });
        });
    }

    // Event listener for deleting a medicine (using event delegation)
    if (medicineListContainer) {
        medicineListContainer.addEventListener('click', function(e) {
            if (e.target && e.target.classList.contains('delete-medicine')) {
                const medicineId = e.target.getAttribute('data-id');
                if (!confirm('Are you sure you want to remove this medicine?')) {
                    return;
                }

                const formData = new FormData();
                formData.append('action', 'delete');
                formData.append('id', medicineId);

                e.target.disabled = true;

                fetch('medicines.php', {
                    method: 'POST',
                    body: formData
                })
                .then(response => response.json())
                .then(data => {
                    if (data.success) {
                        fetchMedicines(); // Refresh the list
                    } else {
                        alert(`Error: ${data.message}`);
                        e.target.disabled = false;
                    }
                })
                .catch(error => {
                    alert('A network error occurred.');
                    e.target.disabled = false;
                });
            }
        });
    }

    // Initial fetch of medicines when the page loads
    if (medicineListContainer) {
        fetchMedicines();
    }
});