/** @odoo-module **/

import { _t } from "@web/core/l10n/translation";
import publicWidget from "@web/legacy/js/public/public_widget";

/**
 * M22 Helpdesk Select Enhancement Widget
 * 
 * Transforms standard select dropdowns in helpdesk forms into modern
 * searchable selects using vanilla JavaScript + Tailwind CSS.
 * No external dependencies - pure modern JavaScript.
 */
publicWidget.registry.M22HelpdeskSelect = publicWidget.Widget.extend({
    selector: '#helpdesk_ticket_form, form[id*="helpdesk"], form[data-model_name="helpdesk.ticket"]',
    
    /**
     * @override
     */
    start: function () {
        const self = this;
        return this._super.apply(this, arguments).then(function () {
            // Wait a bit for form fields to be fully rendered
            setTimeout(function () {
                self._initializeSelects();
            }, 300);
        });
    },

    /**
     * @override
     */
    destroy: function () {
        // Cleanup click outside handlers
        const comboboxes = this.el.querySelectorAll('.m22-combobox-wrapper');
        comboboxes.forEach(wrapper => {
            if (wrapper._clickOutsideHandler) {
                document.removeEventListener('click', wrapper._clickOutsideHandler);
                delete wrapper._clickOutsideHandler;
            }
        });
        this._super.apply(this, arguments);
    },

    //--------------------------------------------------------------------------
    // Private
    //--------------------------------------------------------------------------

    /**
     * Initialize combobox on all select elements in the form
     * @private
     */
    _initializeSelects: function () {
        // Find all select elements with class s_website_form_input (many2one fields)
        // Exclude selects that are already initialized
        const selects = this.el.querySelectorAll('select.s_website_form_input:not(.m22-combobox-processed)');
        
        if (!selects.length) {
            return;
        }

        selects.forEach(select => {
            try {
                select.classList.add('m22-combobox-processed');
                this._transformSelectToCombobox(select);
            } catch (error) {
                console.error(_t('Error initializing combobox:'), error);
            }
        });
    },

    /**
     * Transform a select element into a modern combobox
     * @param {HTMLElement} select
     * @private
     */
    _transformSelectToCombobox: function (select) {
        // Get options from select
        const options = Array.from(select.options).map(opt => ({
            value: opt.value,
            label: opt.textContent.trim(),
            disabled: opt.disabled
        })).filter(opt => opt.value || opt.label);

        // Get current value
        const currentValue = select.value;
        const currentOption = options.find(opt => opt.value === currentValue);
        const placeholder = select.querySelector('option[disabled]')?.textContent?.trim() || _t('Select an option...');
        const searchPlaceholder = _t('Search...');
        const noResultsText = _t('No results found');

        // Create wrapper div
        const wrapper = document.createElement('div');
        wrapper.className = 'relative m22-combobox-wrapper';
        
        // Create state object
        const state = {
            open: false,
            search: '',
            selected: currentOption || null,
            options: options.filter(opt => !opt.disabled),
            placeholder: placeholder,
            searchPlaceholder: searchPlaceholder,
            noResultsText: noResultsText,
            
            get filteredOptions() {
                if (!this.search) return this.options;
                const query = this.search.toLowerCase();
                return this.options.filter(opt => 
                    opt.label.toLowerCase().includes(query)
                );
            },
            
            get hasResults() {
                return this.filteredOptions.length > 0;
            }
        };

        // Build HTML structure with Tailwind classes
        wrapper.innerHTML = `
            <!-- Hidden original select for form submission -->
            <select name="${select.name}" id="${select.id}" class="hidden" ${select.required ? 'required' : ''}>
                ${options.map(opt => 
                    `<option value="${opt.value}" ${opt.value === currentValue ? 'selected' : ''} ${opt.disabled ? 'disabled' : ''}>${opt.label}</option>`
                ).join('')}
            </select>
            
            <!-- Combobox button -->
            <button 
                type="button"
                class="m22-combobox-button w-full rounded-md border border-gray-300 bg-white px-3 py-2 text-left shadow-sm focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500 sm:text-sm ${state.selected ? 'text-gray-900' : 'text-gray-500'}"
            >
                <span class="m22-combobox-placeholder block truncate ${state.selected ? 'hidden' : ''}">${placeholder}</span>
                <span class="m22-combobox-value block truncate ${!state.selected ? 'hidden' : ''}">${state.selected ? state.selected.label : ''}</span>
                <span class="pointer-events-none absolute inset-y-0 right-0 flex items-center pr-2">
                    <svg class="m22-combobox-arrow h-5 w-5 text-gray-400 transition-transform" viewBox="0 0 20 20" fill="currentColor" aria-hidden="true">
                        <path fill-rule="evenodd" d="M10 3a.75.75 0 01.55.24l3.25 3.5a.75.75 0 11-1.1 1.02L10 4.852 7.3 7.76a.75.75 0 01-1.1-1.02l3.25-3.5A.75.75 0 0110 3zm-3.76 9.2a.75.75 0 011.06.04l2.7 2.908 2.7-2.908a.75.75 0 111.1 1.02l-3.25 3.5a.75.75 0 01-1.1 0l-3.25-3.5a.75.75 0 01.04-1.06z" clip-rule="evenodd" />
                    </svg>
                </span>
            </button>
            
            <!-- Dropdown panel -->
            <div 
                class="m22-combobox-dropdown absolute z-[9999] mt-1 max-h-60 w-full overflow-auto rounded-md bg-white py-1 text-base shadow-lg ring-1 ring-black ring-opacity-5 focus:outline-none sm:text-sm hidden"
            >
                <!-- Search input -->
                <div class="sticky top-0 z-10 bg-white px-3 py-2 border-b border-gray-200">
                    <input 
                        type="text"
                        class="m22-combobox-search w-full rounded-md border border-gray-300 px-3 py-2 text-sm focus:border-blue-500 focus:outline-none focus:ring-1 focus:ring-blue-500"
                        placeholder="${searchPlaceholder}"
                    />
                </div>
                
                <!-- Options list -->
                <div class="m22-combobox-options">
                    ${state.options.map(opt => `
                        <div
                            class="m22-combobox-option relative cursor-pointer select-none px-4 py-2 text-gray-900 hover:bg-blue-50 transition-colors ${state.selected && state.selected.value === opt.value ? 'bg-blue-100' : ''}"
                            data-value="${opt.value}"
                        >
                            <span class="block truncate">${this._escapeHtml(opt.label)}</span>
                            ${state.selected && state.selected.value === opt.value ? `
                                <span class="absolute inset-y-0 right-0 flex items-center pr-4 text-blue-600">
                                    <svg class="h-5 w-5" viewBox="0 0 20 20" fill="currentColor" aria-hidden="true">
                                        <path fill-rule="evenodd" d="M16.704 4.153a.75.75 0 01.143 1.052l-8 10.5a.75.75 0 01-1.127.075l-4.5-4.5a.75.75 0 011.06-1.06l3.894 3.893 7.48-9.817a.75.75 0 011.05-.143z" clip-rule="evenodd" />
                                    </svg>
                                </span>
                            ` : ''}
                        </div>
                    `).join('')}
                </div>
                
                <!-- No results -->
                <div class="m22-combobox-no-results px-4 py-2 text-sm text-gray-500 hidden">
                    ${noResultsText}
                </div>
            </div>
        `;

        // Get references to elements
        const button = wrapper.querySelector('.m22-combobox-button');
        const dropdown = wrapper.querySelector('.m22-combobox-dropdown');
        const searchInput = wrapper.querySelector('.m22-combobox-search');
        const optionsContainer = wrapper.querySelector('.m22-combobox-options');
        const noResults = wrapper.querySelector('.m22-combobox-no-results');
        const placeholderSpan = wrapper.querySelector('.m22-combobox-placeholder');
        const valueSpan = wrapper.querySelector('.m22-combobox-value');
        const arrow = wrapper.querySelector('.m22-combobox-arrow');
        const hiddenSelect = wrapper.querySelector('select');

        // Methods
        const updateDisplay = () => {
            if (state.selected) {
                placeholderSpan.classList.add('hidden');
                valueSpan.textContent = state.selected.label;
                valueSpan.classList.remove('hidden');
                button.classList.remove('text-gray-500');
                button.classList.add('text-gray-900');
            } else {
                placeholderSpan.classList.remove('hidden');
                valueSpan.classList.add('hidden');
                button.classList.remove('text-gray-900');
                button.classList.add('text-gray-500');
            }
        };

        const renderOptions = () => {
            const filtered = state.filteredOptions;
            
            if (filtered.length === 0 && state.search) {
                optionsContainer.classList.add('hidden');
                noResults.classList.remove('hidden');
            } else {
                optionsContainer.classList.remove('hidden');
                noResults.classList.add('hidden');
                
                // Update options highlighting
                optionsContainer.querySelectorAll('.m22-combobox-option').forEach(optionEl => {
                    const optionValue = optionEl.dataset.value;
                    const isSelected = state.selected && state.selected.value === optionValue;
                    
                    optionEl.classList.toggle('bg-blue-100', isSelected);
                    
                    // Update checkmark
                    const checkmark = optionEl.querySelector('.absolute');
                    if (isSelected && !checkmark) {
                        const check = document.createElement('span');
                        check.className = 'absolute inset-y-0 right-0 flex items-center pr-4 text-blue-600';
                        check.innerHTML = `
                            <svg class="h-5 w-5" viewBox="0 0 20 20" fill="currentColor" aria-hidden="true">
                                <path fill-rule="evenodd" d="M16.704 4.153a.75.75 0 01.143 1.052l-8 10.5a.75.75 0 01-1.127.075l-4.5-4.5a.75.75 0 011.06-1.06l3.894 3.893 7.48-9.817a.75.75 0 011.05-.143z" clip-rule="evenodd" />
                            </svg>
                        `;
                        optionEl.appendChild(check);
                    } else if (!isSelected && checkmark) {
                        checkmark.remove();
                    }
                    
                    // Show/hide based on search
                    const option = state.options.find(o => o.value === optionValue);
                    if (option) {
                        const matches = !state.search || option.label.toLowerCase().includes(state.search.toLowerCase());
                        optionEl.style.display = matches ? '' : 'none';
                    }
                });
            }
        };

        const selectOption = (option) => {
            state.selected = option;
            state.search = '';
            state.open = false;
            
            // Update hidden select
            hiddenSelect.value = option.value;
            
            // Update display
            updateDisplay();
            renderOptions();
            closeDropdown();
            
            // Trigger change event
            const event = new Event('change', { bubbles: true });
            hiddenSelect.dispatchEvent(event);
        };

        const openDropdown = () => {
            state.open = true;
            dropdown.classList.remove('hidden');
            arrow.classList.add('rotate-180');
            searchInput.focus();
            renderOptions();
        };

        const closeDropdown = () => {
            state.open = false;
            dropdown.classList.add('hidden');
            arrow.classList.remove('rotate-180');
            state.search = '';
            searchInput.value = '';
            renderOptions();
        };

        // Event listeners
        button.addEventListener('click', (e) => {
            e.stopPropagation();
            if (state.open) {
                closeDropdown();
            } else {
                openDropdown();
            }
        });

        searchInput.addEventListener('input', (e) => {
            state.search = e.target.value;
            renderOptions();
        });

        searchInput.addEventListener('keydown', (e) => {
            if (e.key === 'Escape') {
                closeDropdown();
            } else if (e.key === 'Enter' && state.filteredOptions.length > 0) {
                e.preventDefault();
                selectOption(state.filteredOptions[0]);
            }
        });

        optionsContainer.addEventListener('click', (e) => {
            const optionEl = e.target.closest('.m22-combobox-option');
            if (optionEl) {
                const value = optionEl.dataset.value;
                const option = state.options.find(o => o.value === value);
                if (option) {
                    selectOption(option);
                }
            }
        });

        // Click outside handler
        const clickOutsideHandler = (e) => {
            if (state.open && !wrapper.contains(e.target)) {
                closeDropdown();
            }
        };
        document.addEventListener('click', clickOutsideHandler);
        wrapper._clickOutsideHandler = clickOutsideHandler;

        // Keyboard navigation
        optionsContainer.addEventListener('keydown', (e) => {
            if (e.key === 'Escape') {
                closeDropdown();
                button.focus();
            }
        });

        // Replace select with wrapper
        select.parentNode.insertBefore(wrapper, select);
        select.style.display = 'none';
        wrapper.appendChild(select);

        // Initial render
        updateDisplay();
        renderOptions();
    },

    /**
     * Escape HTML to prevent XSS
     * @param {string} text
     * @returns {string}
     * @private
     */
    _escapeHtml: function(text) {
        const div = document.createElement('div');
        div.textContent = text;
        return div.innerHTML;
    }
});