/**
 * MetaSync Add Redirection Form
 *
 * Extracted for Phase 5, #887.
 * Pure JS — form display, tips toggle, source URL management,
 * unsaved-changes warning, and client-side validation.
 *
 * No localized data object required (pure JS, no PHP values).
 *
 * @since Phase 5
 */
(function () {
	// Show the add redirection form when action=add, edit, or redirect (from 404 monitor)
	function showForm() {
		var params = new URLSearchParams(window.location.search);
		var action = params.get('action');
		if (action !== 'add' && action !== 'edit' && action !== 'redirect') {
			return;
		}

		var element = document.getElementById('add-redirection-form');
		if (element) {
			element.style.display = 'block';
		}
	}

	// Try immediately
	showForm();

	// Also try on DOMContentLoaded as backup
	if (document.readyState === 'loading') {
		document.addEventListener('DOMContentLoaded', showForm);
	}
})();

// Handle tips toggle
document.addEventListener('DOMContentLoaded', function () {
	var toggleTipsBtn = document.getElementById('toggle-redirection-tips');
	var tipsContent = document.getElementById('redirection-tips-content');

	if (toggleTipsBtn && tipsContent) {
		toggleTipsBtn.addEventListener('click', function () {
			if (tipsContent.style.display === 'none') {
				tipsContent.style.display = 'block';
				toggleTipsBtn.innerHTML = '<span class="dashicons dashicons-info" style="margin-top: 3px;"></span> Hide Redirection Tips & Examples';
			} else {
				tipsContent.style.display = 'none';
				toggleTipsBtn.innerHTML = '<span class="dashicons dashicons-info" style="margin-top: 3px;"></span> Show Redirection Tips & Examples';
			}
		});
	}

	// Handle regex pattern field visibility
	var searchTypeSelects = document.querySelectorAll('select[name="search_type[]"]');
	var regexRow = document.getElementById('regex_pattern_row');

	function toggleRegexField() {
		var hasRegex = false;
		searchTypeSelects.forEach(function (select) {
			if (select.value === 'regex') {
				hasRegex = true;
			}
		});

		if (regexRow) {
			regexRow.style.display = hasRegex ? 'table-row' : 'none';
		}
	}

	// Initial check
	toggleRegexField();

	// Listen for changes
	searchTypeSelects.forEach(function (select) {
		select.addEventListener('change', toggleRegexField);
	});

	// Handle adding new source URLs
	var addButton = document.getElementById('addNewSourceUrl');
	if (addButton) {
		addButton.addEventListener('click', function () {
			var sourceUrlsList = document.getElementById('source_urls');
			var newItem = document.createElement('li');
			newItem.innerHTML =
                '<input type="text" class="regular-text" name="source_url[]" value="">' +
                '<select name="search_type[]">' +
                    '<option value="exact">Exact Match</option>' +
                    '<option value="start">Starts With</option>' +
                    '<option value="end">Ends With</option>' +
                    '<option value="wildcard">Wildcard (*)</option>' +
                    '<option value="regex">Regex Pattern</option>' +
                '</select>' +
                '<button type="button" class="source_url_delete">Remove</button>';
			sourceUrlsList.appendChild(newItem);

			// Add event listener to new select
			var newSelect = newItem.querySelector('select[name="search_type[]"]');
			newSelect.addEventListener('change', toggleRegexField);

			// Add event listener to remove button
			var removeButton = newItem.querySelector('.source_url_delete');
			removeButton.addEventListener('click', function () {
				newItem.remove();
				toggleRegexField();
			});
		});
	}

	// Handle remove buttons
	document.addEventListener('click', function (e) {
		if (e.target.classList.contains('source_url_delete')) {
			e.target.closest('li').remove();
			toggleRegexField();
		}
	});

	// Track form changes for unsaved changes warning
	var formModified = false;
	var formInputs = document.querySelectorAll('#add-redirection-form input, #add-redirection-form select, #add-redirection-form textarea');

	formInputs.forEach(function (input) {
		// Skip hidden inputs and the cancel button itself
		if (input.type !== 'hidden' && input.id !== 'cancel-redirection') {
			input.addEventListener('change', function () {
				formModified = true;
			});
			input.addEventListener('input', function () {
				formModified = true;
			});
		}
	});

	// Handle cancel button
	var cancelButton = document.getElementById('cancel-redirection');
	if (cancelButton) {
		cancelButton.addEventListener('click', function (e) {
			e.preventDefault();

			// Check if form has been modified
			if (formModified) {
				var confirmCancel = confirm('You have unsaved changes. Are you sure you want to cancel?');
				if (!confirmCancel) {
					return;
				}
			}

			// Redirect back to redirections list
			// The cancel URL is set as a data attribute on the button by the server
			var cancelUrl = cancelButton.getAttribute('data-cancel-url');
			if (cancelUrl) {
				window.location.href = cancelUrl;
			} else {
				window.history.back();
			}
		});
	}

	// Warn user about unsaved changes when leaving page
	window.addEventListener('beforeunload', function (e) {
		if (formModified) {
			e.preventDefault();
			e.returnValue = ''; // Modern browsers require this
			return ''; // Some older browsers show this message
		}
	});


	// Validation helper functions
	function showError(element, message) {
		// Remove any existing error
		hideError(element);

		// Create error message
		var errorDiv = document.createElement('div');
		errorDiv.className = 'validation-error';
		errorDiv.style.cssText = 'color: var(--dashboard-error); font-size: 13px; margin-top: 5px; font-weight: 500; width: 100%;';
		errorDiv.textContent = message;

		// Add error styling to input
		element.style.borderColor = 'var(--dashboard-error)';
		element.style.boxShadow = '0 0 0 3px rgba(239, 68, 68, 0.1)';

		// Insert error below the parent li (or after element if no li)
		var li = element.closest('li');
		if (li) {
			li.style.flexWrap = 'wrap';
			li.appendChild(errorDiv);
		} else {
			element.parentNode.insertBefore(errorDiv, element.nextSibling);
		}
	}

	function hideError(element) {
		// Remove error styling
		element.style.borderColor = '';
		element.style.boxShadow = '';

		// Remove error message from parent li or sibling
		var li = element.closest('li');
		if (li) {
			var err = li.querySelector('.validation-error');
			if (err) {
				err.remove();
			}
			li.style.flexWrap = '';
		} else {
			var nextEl = element.nextElementSibling;
			if (nextEl && nextEl.classList.contains('validation-error')) {
				nextEl.remove();
			}
		}
	}

	function validateURL(url) {
		// Allow relative paths starting with /
		if (url.startsWith('/')) {
			return true;
		}

		// Allow full URLs
		try {
			new URL(url);
			return true;
		} catch (e) {
			return false;
		}
	}

	function isValidRegex(pattern) {
		try {
			new RegExp(pattern);
			return true;
		} catch (e) {
			return false;
		}
	}

	// Real-time validation for inputs
	function setupRealtimeValidation() {
		// Validate source URLs on blur
		document.addEventListener('blur', function (e) {
			if (e.target.matches('input[name="source_url[]"]')) {
				var value = e.target.value.trim();
				if (value && !validateURL(value)) {
					showError(e.target, 'Please enter a valid URL (e.g., /path or https://example.com)');
				} else {
					hideError(e.target);
				}
			}
		}, true);

		// Validate destination URL on blur
		var destinationUrl = document.getElementById('destination_url');
		if (destinationUrl) {
			destinationUrl.addEventListener('blur', function () {
				var value = this.value.trim();
				var redirectType = document.querySelector('input[name="redirect_type"]:checked');

				if (redirectType && redirectType.value !== '410' && redirectType.value !== '451') {
					if (value && !validateURL(value)) {
						showError(this, 'Please enter a valid URL (e.g., /path or https://example.com)');
					} else {
						hideError(this);
					}
				}
			});
		}

		// Validate regex pattern on blur
		var regexPattern = document.getElementById('regex_pattern');
		if (regexPattern) {
			regexPattern.addEventListener('blur', function () {
				var value = this.value.trim();
				if (value && !isValidRegex(value)) {
					showError(this, 'Invalid regex pattern. Example: /^\\/old-path\\/.*$/');
				} else {
					hideError(this);
				}
			});
		}
	}

	setupRealtimeValidation();

	// Form validation on submit
	var form = document.querySelector('#redirection-form');
	if (form) {
		form.addEventListener('submit', function (e) {
			// Skip validation for filter/search submits — only validate the Save button.
			var submitter = e.submitter;
			if (submitter && submitter.name !== 'submit') {
				return true;
			}

			var isValid = true;
			var errors = [];

			// Clear all previous errors
			document.querySelectorAll('.validation-error').forEach(function (el) {
				el.remove(); 
			});
			document.querySelectorAll('input[type="text"], input[type="url"], select').forEach(function (el) {
				el.style.borderColor = '';
				el.style.boxShadow = '';
			});

			// 1. Validate source URLs
			var sourceInputs = document.querySelectorAll('input[name="source_url[]"]');
			var sourceUrls = [];
			var hasEmptySource = false;
			var hasInvalidSource = false;

			sourceInputs.forEach(function (input) {
				var value = input.value.trim();

				if (!value) {
					hasEmptySource = true;
					showError(input, 'Source URL is required');
					isValid = false;
				} else if (!validateURL(value)) {
					hasInvalidSource = true;
					showError(input, 'Please enter a valid URL (e.g., /path or https://example.com)');
					isValid = false;
				} else {
					// Check for duplicates
					if (sourceUrls.includes(value)) {
						showError(input, 'Duplicate source URL detected');
						isValid = false;
					} else {
						sourceUrls.push(value);
					}
				}
			});

			if (hasEmptySource) {
				errors.push('All source URL fields must be filled in.');
			}
			if (hasInvalidSource) {
				errors.push('Please enter valid URLs for all source fields.');
			}

			// 2. Validate redirection type
			var redirectType = document.querySelector('input[name="redirect_type"]:checked');
			if (!redirectType) {
				errors.push('Please select a redirection type.');
				isValid = false;
			}

			// 3. Validate destination URL (if required)
			var destinationUrlEl = document.getElementById('destination_url');
			if (redirectType && redirectType.value !== '410' && redirectType.value !== '451') {
				var destValue = destinationUrlEl.value.trim();
				if (!destValue) {
					showError(destinationUrlEl, 'Destination URL is required for this redirect type');
					errors.push('Please enter a destination URL.');
					isValid = false;
				} else if (!validateURL(destValue)) {
					showError(destinationUrlEl, 'Please enter a valid URL (e.g., /path or https://example.com)');
					errors.push('Please enter a valid destination URL.');
					isValid = false;
				}
			}

			// 4. Validate regex pattern (if regex is selected)
			var hasRegexPattern = false;
			document.querySelectorAll('select[name="search_type[]"]').forEach(function (select) {
				if (select.value === 'regex') {
					hasRegexPattern = true;
				}
			});

			if (hasRegexPattern) {
				var regexPatternEl = document.getElementById('regex_pattern');
				var regexValue = regexPatternEl ? regexPatternEl.value.trim() : '';

				if (!regexValue) {
					if (regexPatternEl) {
						showError(regexPatternEl, 'Regex pattern is required when using "Regex Pattern" type');
					}
					errors.push('Please enter a regex pattern when using "Regex Pattern" as the pattern type.');
					isValid = false;
				} else if (!isValidRegex(regexValue)) {
					if (regexPatternEl) {
						showError(regexPatternEl, 'Invalid regex pattern. Example: /^\\/old-path\\/.*$/');
					}
					errors.push('Invalid regex pattern. Please fix the regex pattern.');
					isValid = false;
				}
			}

			// 5. Validate status is selected
			var status = document.querySelector('input[name="status"]:checked');
			if (!status) {
				errors.push('Please select a status (Active or Inactive).');
				isValid = false;
			}

			// Show consolidated error message if validation fails
			if (!isValid) {
				e.preventDefault();

				// Create or update error summary at the top of the form
				var errorSummary = document.getElementById('validation-error-summary');
				if (!errorSummary) {
					errorSummary = document.createElement('div');
					errorSummary.id = 'validation-error-summary';
					errorSummary.style.cssText = 'background: rgba(239, 68, 68, 0.1); border: 1px solid var(--dashboard-error); border-radius: 8px; padding: 15px; margin-bottom: 20px; color: var(--dashboard-error);';

					var formDiv = document.getElementById('add-redirection-form');
					var firstTable = formDiv.querySelector('.form-table');
					formDiv.insertBefore(errorSummary, firstTable);
				}

				var uniqueErrors = errors.filter(function (err, idx, arr) {
					return arr.indexOf(err) === idx; 
				});
				errorSummary.innerHTML = '<strong>Please fix the following errors:</strong><ul style="margin: 10px 0 0 20px; padding: 0;">' +
					uniqueErrors.map(function (err) {
						return '<li>' + err + '</li>';
					}).join('') +
					'</ul>';

				// Scroll to error summary
				errorSummary.scrollIntoView({ behavior: 'smooth', block: 'center' });

				return false;
			} else {
				// Remove error summary if it exists
				var existingSummary = document.getElementById('validation-error-summary');
				if (existingSummary) {
					existingSummary.remove();
				}
			}

			// If validation passes, clear the modified flag to prevent beforeunload warning
			formModified = false;
		});
	}
});