import React, { useState, useEffect } from 'react';
import { createPortal } from 'react-dom';
import { Plus, Edit2, Trash2, FileText, Loader2, X, Sparkles, Sliders, Hash, Type, Brain, Copy, Check } from 'lucide-react';
import { motion, AnimatePresence } from 'framer-motion';
import { useLanguage } from '../../contexts/LanguageContext';
import { useToast } from '../../contexts/ToastContext';
import { useConfirm } from '../../contexts/ConfirmContext';
import { templateService } from '../../services/templateService';
import { knowledgeGroupService } from '../../services/knowledgeGroupService';
import { AssessmentTemplate, CreateTemplateData, UpdateTemplateData, KnowledgeGroup } from '../../types';

export const AssessmentTemplateManager: React.FC = () => {
    const { t } = useLanguage();
    const { showSuccess, showError } = useToast();
    const { confirm } = useConfirm();
    const [templates, setTemplates] = useState<AssessmentTemplate[]>([]);
    const [groups, setGroups] = useState<KnowledgeGroup[]>([]);
    const [isLoading, setIsLoading] = useState(false);
    const [isSaving, setIsSaving] = useState(false);
    const [showModal, setShowModal] = useState(false);
    const [editingTemplate, setEditingTemplate] = useState<AssessmentTemplate | null>(null);
    
    // UI state uses strings for easy input
    const [formData, setFormData] = useState({
        name: '',
        description: '',
        keywords: '',
        questionCount: 5,
        difficultyDistribution: 'Basic: 30%, Intermediate: 40%, Advanced: 30%',
        style: 'Professional',
        knowledgeGroupId: '',
    });
    const [copiedId, setCopiedId] = useState<string | null>(null);

    const fetchTemplates = async () => {
        setIsLoading(true);
        try {
            const data = await templateService.getAll();
            setTemplates(data);
        } catch (error) {
            console.error('Failed to fetch templates:', error);
            showError(t('actionFailed'));
        } finally {
            setIsLoading(false);
        }
    };

    const fetchGroups = async () => {
        try {
            const data = await knowledgeGroupService.getGroups();
            setGroups(data);
        } catch (error) {
            console.error('Failed to fetch groups:', error);
        }
    };

    useEffect(() => {
        fetchTemplates();
        fetchGroups();
    }, []);

    const handleOpenModal = (template?: AssessmentTemplate) => {
        if (template) {
            setEditingTemplate(template);
            setFormData({
                name: template.name,
                description: template.description || '',
                keywords: Array.isArray(template.keywords) ? template.keywords.join(', ') : '',
                questionCount: template.questionCount,
                difficultyDistribution: typeof template.difficultyDistribution === 'object' 
                    ? JSON.stringify(template.difficultyDistribution)
                    : (template.difficultyDistribution || ''),
                style: template.style || 'Professional',
                knowledgeGroupId: template.knowledgeGroupId || '',
            });
        } else {
            setEditingTemplate(null);
            setFormData({
                name: '',
                description: '',
                keywords: '',
                questionCount: 5,
                difficultyDistribution: '{"Basic": 3, "Intermediate": 4, "Advanced": 3}',
                style: 'Professional',
                knowledgeGroupId: '',
            });
        }
        setShowModal(true);
    };

    const handleSave = async (e: React.FormEvent) => {
        e.preventDefault();
        setIsSaving(true);
        try {
            // Convert UI strings back to required types
            const keywordsArray = formData.keywords.split(',').map(k => k.trim()).filter(k => k !== '');
            let diffDist: any = formData.difficultyDistribution;
            try {
                if (formData.difficultyDistribution.startsWith('{')) {
                    diffDist = JSON.parse(formData.difficultyDistribution);
                }
            } catch (e) {
                // Keep as string if parsing fails
            }

            const payload: CreateTemplateData = {
                name: formData.name,
                description: formData.description,
                keywords: keywordsArray,
                questionCount: formData.questionCount,
                difficultyDistribution: diffDist,
                style: formData.style,
                knowledgeGroupId: formData.knowledgeGroupId || undefined,
            };

            if (editingTemplate) {
                await templateService.update(editingTemplate.id, payload as UpdateTemplateData);
                showSuccess(t('featureUpdated'));
            } else {
                await templateService.create(payload);
                showSuccess(t('confirm'));
            }
            setShowModal(false);
            fetchTemplates();
        } catch (error) {
            console.error('Save failed:', error);
            showError(t('actionFailed'));
        } finally {
            setIsSaving(false);
        }
    };

    const handleCopyId = async (id: string) => {
        try {
            await navigator.clipboard.writeText(id);
            setCopiedId(id);
            showSuccess(t('copySuccess') || 'ID copied to clipboard');
            setTimeout(() => setCopiedId(null), 2000);
        } catch (err) {
            showError(t('actionFailed'));
        }
    };

    const handleDelete = async (id: string) => {
        if (!(await confirm(t('confirmTitle')))) return;
        try {
            await templateService.delete(id);
            showSuccess(t('confirm'));
            fetchTemplates();
        } catch (error) {
            showError(t('actionFailed'));
        }
    };

    const renderDifficulty = (dist: any) => {
        if (typeof dist === 'string') return dist;
        if (typeof dist === 'object' && dist !== null) {
            return Object.entries(dist).map(([k, v]) => `${k}: ${v}`).join(', ');
        }
        return '';
    };

    return (
        <div className="space-y-6">
            <div className="flex items-center justify-between mb-2">
                <div className="flex items-center gap-3">
                    <div className="w-10 h-10 bg-indigo-50 text-indigo-600 rounded-xl flex items-center justify-center">
                        <FileText size={22} />
                    </div>
                    <div>
                        <h3 className="text-lg font-bold text-slate-900">{t('assessmentTemplates')}</h3>
                        <p className="text-xs text-slate-500">{t('assessmentTemplatesSubtitle')}</p>
                    </div>
                </div>
                <button
                    onClick={() => handleOpenModal()}
                    className="px-4 py-2.5 bg-indigo-600 text-white rounded-xl text-sm font-black flex items-center gap-2 shadow-lg shadow-indigo-100 hover:bg-indigo-700 transition-all active:scale-95"
                >
                    <Plus size={18} />
                    {t('createTemplate')}
                </button>
            </div>

            {isLoading ? (
                <div className="flex items-center justify-center py-20">
                    <Loader2 className="w-8 h-8 animate-spin text-indigo-600 opacity-20" />
                </div>
            ) : templates.length === 0 ? (
                <div className="bg-slate-50 rounded-[2rem] border-2 border-dashed border-slate-200 p-16 text-center">
                    <FileText className="w-12 h-12 text-slate-200 mx-auto mb-4" />
                    <p className="text-slate-400 font-bold uppercase tracking-widest text-xs">{t('mmEmpty')}</p>
                </div>
            ) : (
                <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-4">
                    {templates.map((template) => (
                        <motion.div
                            key={template.id}
                            initial={{ opacity: 0, scale: 0.95 }}
                            animate={{ opacity: 1, scale: 1 }}
                            className="bg-white border border-slate-200 rounded-3xl p-5 shadow-sm hover:shadow-md transition-all group relative overflow-hidden"
                        >
                            <div className="absolute top-0 right-0 w-24 h-24 bg-indigo-500/5 rounded-full blur-3xl -mr-12 -mt-12" />
                            
                            <div className="flex justify-between items-start mb-4 relative z-10">
                                <h4 className="text-base font-black text-slate-900 truncate pr-8">{template.name}</h4>
                                <div className="flex gap-1">
                                    <button
                                        onClick={() => handleOpenModal(template)}
                                        className="p-1.5 text-slate-400 hover:text-indigo-600 hover:bg-indigo-50 rounded-lg transition-all"
                                    >
                                        <Edit2 size={14} />
                                    </button>
                                    <button
                                        onClick={() => handleDelete(template.id)}
                                        className="p-1.5 text-slate-400 hover:text-red-600 hover:bg-red-50 rounded-lg transition-all"
                                    >
                                        <Trash2 size={14} />
                                    </button>
                                </div>
                            </div>

                            <p className="text-xs text-slate-500 mb-4 line-clamp-2 h-8">{template.description || t('noDescription')}</p>

                            <div className="grid grid-cols-2 gap-2 mb-2">
                                <div className="bg-slate-50 rounded-xl p-2 border border-slate-100">
                                    <span className="block text-[8px] font-black text-slate-400 uppercase tracking-widest mb-0.5">{t('questionCount')}</span>
                                    <span className="text-xs font-bold text-slate-700">{template.questionCount}</span>
                                </div>
                                <div className="bg-slate-50 rounded-xl p-2 border border-slate-100 overflow-hidden">
                                    <span className="block text-[8px] font-black text-slate-400 uppercase tracking-widest mb-0.5">{t('difficultyDistribution')}</span>
                                    <span className="text-xs font-bold text-slate-700 truncate block">
                                        {renderDifficulty(template.difficultyDistribution)}
                                    </span>
                                </div>
                            </div>

                            <div className="bg-slate-50 rounded-xl p-2 border border-slate-100 mb-2 flex items-center justify-between group/id">
                                <div className="flex flex-col min-w-0">
                                    <span className="block text-[8px] font-black text-slate-400 uppercase tracking-widest mb-0.5">Template ID</span>
                                    <span className="text-[10px] font-mono font-medium text-slate-500 truncate">{template.id}</span>
                                </div>
                                <button
                                    onClick={() => handleCopyId(template.id)}
                                    className="p-1.5 text-slate-400 hover:text-indigo-600 hover:bg-white rounded-lg transition-all opacity-0 group-hover/id:opacity-100"
                                    title="Copy ID"
                                >
                                    {copiedId === template.id ? <Check size={12} className="text-emerald-500" /> : <Copy size={12} />}
                                </button>
                            </div>

                            <div className="bg-indigo-50/30 rounded-xl p-2 border border-indigo-100/50 mb-4 flex items-center gap-2">
                                <Brain size={12} className="text-indigo-500" />
                                <span className="text-[10px] font-bold text-indigo-700 truncate">
                                    {template.knowledgeGroup?.name || t('selectKnowledgeGroup')}
                                </span>
                            </div>

                            <div className="flex flex-wrap gap-1.5 pt-4 border-t border-slate-50">
                                {Array.isArray(template.keywords) && template.keywords.map((kw, i) => (
                                    <span key={i} className="px-2 py-0.5 bg-indigo-50 text-indigo-600 text-[10px] font-bold rounded-full border border-indigo-100/50">
                                        {kw}
                                    </span>
                                ))}
                                {(!template.keywords || template.keywords.length === 0) && <span className="text-[10px] text-slate-400 italic">No keywords</span>}
                            </div>
                        </motion.div>
                    ))}
                </div>
            )}

            {createPortal(
                <AnimatePresence>
                    {showModal && (
                        <div key="assessment-template-modal" className="fixed inset-0 z-[1000] flex items-center justify-center p-4">
                            <motion.div
                                initial={{ opacity: 0 }}
                                animate={{ opacity: 1 }}
                                exit={{ opacity: 0 }}
                                onClick={() => setShowModal(false)}
                                className="absolute inset-0 bg-slate-900/40 backdrop-blur-sm"
                            />
                            <motion.div
                                initial={{ opacity: 0, scale: 0.9, y: 20 }}
                                animate={{ opacity: 1, scale: 1, y: 0 }}
                                exit={{ opacity: 0, scale: 0.9, y: 20 }}
                                className="w-full max-w-xl bg-white rounded-[2.5rem] shadow-2xl relative z-10 overflow-hidden"
                            >
                                <div className="p-8 pb-4 flex items-center justify-between border-b border-slate-100">
                                    <div className="flex items-center gap-3">
                                        <div className="w-12 h-12 bg-indigo-50 text-indigo-600 rounded-2xl flex items-center justify-center">
                                            {editingTemplate ? <Edit2 size={24} /> : <Plus size={24} />}
                                        </div>
                                        <h3 className="text-xl font-black text-slate-900">
                                            {editingTemplate ? t('editTemplate') : t('createTemplate')}
                                        </h3>
                                    </div>
                                    <button onClick={() => setShowModal(false)} className="p-2 text-slate-400 hover:text-slate-600 hover:bg-slate-50 rounded-xl transition-all">
                                        <X size={20} />
                                    </button>
                                </div>

                                <form onSubmit={handleSave} className="p-8 space-y-5">
                                    <div className="grid grid-cols-1 md:grid-cols-2 gap-5">
                                        <div className="space-y-1.5 md:col-span-2">
                                            <label className="text-[10px] font-black text-slate-400 uppercase tracking-widest px-1 ml-1 flex items-center gap-2">
                                                <Type size={12} className="text-indigo-500" />
                                                {t('templateName')} *
                                            </label>
                                            <input
                                                required
                                                className="w-full px-5 py-4 bg-slate-50 border border-slate-200 rounded-[1.25rem] text-sm font-bold focus:ring-4 focus:ring-indigo-500/10 focus:border-indigo-500/50 outline-none transition-all placeholder:text-slate-300"
                                                value={formData.name}
                                                onChange={e => setFormData({ ...formData, name: e.target.value })}
                                                placeholder="e.g. Senior Frontend Engineer Technical Interview"
                                            />
                                        </div>

                                        <div className="space-y-1.5 md:col-span-2">
                                            <label className="text-[10px] font-black text-slate-400 uppercase tracking-widest px-1 ml-1 flex items-center gap-2">
                                                <Sparkles size={12} className="text-indigo-500" />
                                                {t('keywords')} ({t('keywordsHint')})
                                            </label>
                                            <input
                                                className="w-full px-5 py-4 bg-slate-50 border border-slate-200 rounded-[1.25rem] text-sm font-bold focus:ring-4 focus:ring-indigo-500/10 focus:border-indigo-500/50 outline-none transition-all placeholder:text-slate-300"
                                                value={formData.keywords}
                                                onChange={e => setFormData({ ...formData, keywords: e.target.value })}
                                                placeholder={t('keywordsHint')}
                                            />
                                        </div>

                                        <div className="space-y-1.5">
                                            <label className="text-[10px] font-black text-slate-400 uppercase tracking-widest px-1 ml-1 flex items-center gap-2">
                                                <Hash size={12} className="text-indigo-500" />
                                                {t('questionCount')}
                                            </label>
                                            <input
                                                type="number"
                                                className="w-full px-5 py-4 bg-slate-50 border border-slate-200 rounded-[1.25rem] text-sm font-bold focus:ring-4 focus:ring-indigo-500/10 focus:border-indigo-500/50 outline-none transition-all"
                                                value={formData.questionCount}
                                                onChange={e => setFormData({ ...formData, questionCount: parseInt(e.target.value) })}
                                            />
                                        </div>

                                        <div className="space-y-1.5">
                                            <label className="text-[10px] font-black text-slate-400 uppercase tracking-widest px-1 ml-1 flex items-center gap-2">
                                                <Sliders size={12} className="text-indigo-500" />
                                                {t('difficultyDistribution')}
                                            </label>
                                            <input
                                                className="w-full px-5 py-4 bg-slate-50 border border-slate-200 rounded-[1.25rem] text-sm font-bold focus:ring-4 focus:ring-indigo-500/10 focus:border-indigo-500/50 outline-none transition-all"
                                                value={formData.difficultyDistribution}
                                                onChange={e => setFormData({ ...formData, difficultyDistribution: e.target.value })}
                                                placeholder='{"Basic": 3, "Inter": 4, "Adv": 3}'
                                            />
                                        </div>

                                        <div className="space-y-1.5 md:col-span-2">
                                            <label className="text-[10px] font-black text-slate-400 uppercase tracking-widest px-1 ml-1 flex items-center gap-2">
                                                <Sliders size={12} className="text-indigo-500" />
                                                {t('selectKnowledgeGroup')} *
                                            </label>
                                            <select
                                                required
                                                className="w-full px-5 py-4 bg-slate-50 border border-slate-200 rounded-[1.25rem] text-sm font-bold focus:ring-4 focus:ring-indigo-500/10 focus:border-indigo-500/50 outline-none transition-all appearance-none cursor-pointer"
                                                value={formData.knowledgeGroupId}
                                                onChange={e => setFormData({ ...formData, knowledgeGroupId: e.target.value })}
                                            >
                                                <option value="" disabled>{t('selectKnowledgeGroup')}</option>
                                                {groups.map(group => (
                                                    <option key={group.id} value={group.id}>{group.name}</option>
                                                ))}
                                            </select>
                                        </div>

                                        <div className="space-y-1.5 md:col-span-2">
                                            <label className="text-[10px] font-black text-slate-400 uppercase tracking-widest px-1 ml-1 flex items-center gap-2">
                                                <Sliders size={12} className="text-indigo-500" />
                                                {t('style')}
                                            </label>
                                            <input
                                                className="w-full px-5 py-4 bg-slate-50 border border-slate-200 rounded-[1.25rem] text-sm font-bold focus:ring-4 focus:ring-indigo-500/10 focus:border-indigo-500/50 outline-none transition-all"
                                                value={formData.style}
                                                onChange={e => setFormData({ ...formData, style: e.target.value })}
                                            />
                                        </div>
                                    </div>

                                    <div className="flex justify-end gap-3 pt-4">
                                        <button
                                            type="button"
                                            onClick={() => setShowModal(false)}
                                            className="px-6 py-4 text-sm font-black text-slate-500 hover:text-slate-700 transition-colors"
                                        >
                                            {t('mmCancel')}
                                        </button>
                                        <button
                                            type="submit"
                                            disabled={isSaving}
                                            className="px-10 py-4 bg-indigo-600 text-white rounded-[1.25rem] font-black uppercase tracking-widest text-xs shadow-xl shadow-indigo-100 hover:bg-indigo-700 transition-all active:scale-95 flex items-center gap-2"
                                        >
                                            {isSaving && <Loader2 size={16} className="animate-spin" />}
                                            {t('save')}
                                        </button>
                                    </div>
                                </form>
                            </motion.div>
                        </div>
                    )}
                </AnimatePresence>,
                document.body
            )}
        </div>
    );
};
