import React, { Component } from 'react';
import Box from '@mui/material/Box';
import Button from '@mui/material/Button';
import Menu from '@mui/material/Menu';
import MenuItem from '@mui/material/MenuItem';
import Typography from '@mui/material/Typography';
import { withI18n } from '../i18n/withTranslation.js';

class LanguageSwitcher extends Component {
  constructor(props) {
    super(props);
    
    this.state = {
      anchorEl: null,
      loadedFlags: {}
    };
  }

  handleClick = (event) => {
    this.setState({ anchorEl: event.currentTarget });
  };

  handleClose = () => {
    this.setState({ anchorEl: null });
  };

  handleLanguageChange = (language) => {
    const { languageContext } = this.props;
    if (languageContext) {
      languageContext.changeLanguage(language);
    }
    this.handleClose();
  };

  // Lazy load flag components
  loadFlagComponent = async (lang) => {
    if (this.state.loadedFlags[lang]) {
      return this.state.loadedFlags[lang];
    }

    try {
      const flagMap = {
        'de': () => import('country-flag-icons/react/3x2').then(m => m.DE),
        'en': () => import('country-flag-icons/react/3x2').then(m => m.US),
        'es': () => import('country-flag-icons/react/3x2').then(m => m.ES),
        'fr': () => import('country-flag-icons/react/3x2').then(m => m.FR),
        'it': () => import('country-flag-icons/react/3x2').then(m => m.IT),
        'pl': () => import('country-flag-icons/react/3x2').then(m => m.PL),
        'hu': () => import('country-flag-icons/react/3x2').then(m => m.HU),
        'sr': () => import('country-flag-icons/react/3x2').then(m => m.RS),
        'bg': () => import('country-flag-icons/react/3x2').then(m => m.BG),
        'ru': () => import('country-flag-icons/react/3x2').then(m => m.RU),
        'uk': () => import('country-flag-icons/react/3x2').then(m => m.UA),
        'sk': () => import('country-flag-icons/react/3x2').then(m => m.SK),
        'cs': () => import('country-flag-icons/react/3x2').then(m => m.CZ),
        'ro': () => import('country-flag-icons/react/3x2').then(m => m.RO),
        'zh': () => import('country-flag-icons/react/3x2').then(m => m.CN)
      };

      const flagLoader = flagMap[lang];
      if (flagLoader) {
        const FlagComponent = await flagLoader();
        this.setState(prevState => ({
          loadedFlags: {
            ...prevState.loadedFlags,
            [lang]: FlagComponent
          }
        }));
        return FlagComponent;
      }
    } catch (error) {
      console.warn(`Failed to load flag for language: ${lang}`, error);
    }
    return null;
  };

  getLanguageFlag = (lang) => {
    const FlagComponent = this.state.loadedFlags[lang];
    
    if (FlagComponent) {
      return (
        <FlagComponent 
          style={{ 
            width: '20px', 
            height: '14px',
            borderRadius: '2px',
            border: '1px solid #ddd'
          }} 
        />
      );
    }
    
    // Loading placeholder or fallback
    return (
      <Box
        component="span"
        sx={{
          display: 'inline-flex',
          alignItems: 'center',
          justifyContent: 'center',
          minWidth: '20px',
          height: '14px',
          backgroundColor: '#f5f5f5',
          color: '#666',
          fontSize: '8px',
          fontWeight: 'bold',
          borderRadius: '2px',
          fontFamily: 'monospace',
          border: '1px solid #ddd'
        }}
      >
        {this.getLanguageLabel(lang)}
      </Box>
    );
  };

  // Load flags when menu opens
  componentDidUpdate(prevProps, prevState) {
    const { anchorEl } = this.state;
    const { languageContext } = this.props;
    
    if (anchorEl && !prevState.anchorEl && languageContext) {
      // Menu just opened, lazy load all flags
      languageContext.availableLanguages.forEach(lang => {
        if (!this.state.loadedFlags[lang]) {
          this.loadFlagComponent(lang);
        }
      });
    }
  }

  getLanguageLabel = (lang) => {
    const labels = {
      'de': 'DE',
      'en': 'US',
      'es': 'ES',
      'fr': 'FR',
      'it': 'IT',
      'pl': 'PL',
      'hu': 'HU',
      'sr': 'RS',
      'bg': 'BG',
      'ru': 'RU',
      'uk': 'UA',
      'sk': 'SK',
      'cs': 'CZ',
      'ro': 'RO',
      'zh': 'CN'
    };
    return labels[lang] || lang.toUpperCase();
  };

  getLanguageName = (lang) => {
    const names = {
      'de': 'Deutsch',
      'en': 'English',
      'es': 'Español',
      'fr': 'Français',
      'it': 'Italiano',
      'pl': 'Polski',
      'hu': 'Magyar',
      'sr': 'Српски',
      'bg': 'Български',
      'ru': 'Русский',
      'uk': 'Українська',
      'sk': 'Slovenčina',
      'cs': 'Čeština',
      'ro': 'Română',
      'zh': '中文'
    };
    return names[lang] || lang;
  };

  render() {
    const { languageContext } = this.props;
    const { anchorEl } = this.state;
    
    if (!languageContext) {
      return null;
    }

    const { currentLanguage, availableLanguages } = languageContext;
    const open = Boolean(anchorEl);

    return (
      <Box sx={{ display: 'flex', alignItems: 'center' }}>
        <Button
          aria-controls={open ? 'language-menu' : undefined}
          aria-haspopup="true"
          aria-expanded={open ? 'true' : undefined}
          onClick={this.handleClick}
          color="inherit"
          size="small"
          sx={{ 
            my: 1, 
            mx: 0.5,
            minWidth: 'auto',
            textTransform: 'none',
            fontSize: '0.875rem'
          }}
        >
          {this.getLanguageLabel(currentLanguage)}
        </Button>
        <Menu
          id="language-menu"
          anchorEl={anchorEl}
          open={open}
          onClose={this.handleClose}
          disableScrollLock={true}
          MenuListProps={{
            'aria-labelledby': 'language-button',
          }}
          anchorOrigin={{
            vertical: 'bottom',
            horizontal: 'right',
          }}
          transformOrigin={{
            vertical: 'top',
            horizontal: 'right',
          }}
        >
          {availableLanguages.map((language) => (
            <MenuItem
              key={language}
              onClick={() => this.handleLanguageChange(language)}
              selected={language === currentLanguage}
              sx={{ 
                minWidth: 160,
                display: 'flex',
                justifyContent: 'space-between',
                gap: 2
              }}
            >
              <Box sx={{ display: 'flex', alignItems: 'center', gap: 1 }}>
                {this.getLanguageFlag(language)}
                <Typography variant="body2">
                  {this.getLanguageName(language)}
                </Typography>
              </Box>
              <Typography variant="caption" color="text.secondary" sx={{ ml: 'auto' }}>
                {this.getLanguageLabel(language)}
              </Typography>
            </MenuItem>
          ))}
        </Menu>
      </Box>
    );
  }
}

export default withI18n()(LanguageSwitcher);