import React, { useState, useEffect } from 'react';
import { useNavigate, useLocation, useParams } from 'react-router-dom';
import {
  Box,
  Drawer,
  AppBar,
  Toolbar,
  IconButton,
  Typography,
  List,
  ListItem,
  ListItemButton,
  ListItemIcon,
  ListItemText,
  Paper,
  Grid,
  Card,
  CardContent,
  CardActionArea,
  useTheme,
  useMediaQuery
} from '@mui/material';
import MenuIcon from '@mui/icons-material/Menu';
import PersonIcon from '@mui/icons-material/Person';
import CloseIcon from '@mui/icons-material/Close';
import ArrowBackIcon from '@mui/icons-material/ArrowBack';
import DescriptionIcon from '@mui/icons-material/Description';
import CodeIcon from '@mui/icons-material/Code';
import LayersIcon from '@mui/icons-material/Layers';
import DashboardIcon from '@mui/icons-material/Dashboard';
import PaletteIcon from '@mui/icons-material/Palette';
import AnalyticsIcon from '@mui/icons-material/Analytics';
import ViewQuiltIcon from '@mui/icons-material/ViewQuilt';

import { Document } from '../components/Document';
import { BackstoryPageProps } from '../components/BackstoryTab';
import { BackstoryUIOverviewPage } from 'documents/BackstoryUIOverviewPage';
import { BackstoryAppAnalysisPage } from 'documents/BackstoryAppAnalysisPage';
import { BackstoryThemeVisualizerPage } from 'documents/BackstoryThemeVisualizerPage';
import { UserManagement } from 'documents/UserManagement';
import { MockupPage } from 'documents/MockupPage';
import { useAppState } from 'hooks/GlobalContext';

// Sidebar navigation component using MUI components
const Sidebar: React.FC<{
  currentPage: string;
  onDocumentSelect: (docName: string, open: boolean) => void;
  onClose?: () => void;
  isMobile: boolean;
}> = ({ currentPage, onDocumentSelect, onClose, isMobile }) => {
  const navigate = useNavigate();

  // Document definitions

  const handleItemClick = (route: string) => {
    onDocumentSelect(route, true);
    if (isMobile && onClose) {
      onClose();
    }
  };

  return (
    <Box sx={{ height: '100%', display: 'flex', flexDirection: 'column' }}>
      <Box sx={{
        p: 2,
        display: 'flex',
        alignItems: 'center',
        justifyContent: 'space-between',
        borderBottom: 1,
        borderColor: 'divider',
      }}>
        <Typography variant="h6" component="h2" fontWeight="bold">
          Documentation
        </Typography>
        {isMobile && onClose && (
          <IconButton
            onClick={onClose}
            size="small"
            aria-label="Close navigation"
          >
            <CloseIcon />
          </IconButton>
        )}
      </Box>

      <Box sx={{
        flexGrow: 1,
        overflow: 'auto',
        p: 1
      }}>
        <List>
          {documents.map((doc, index) => (
            <ListItem key={index} disablePadding>
              <ListItemButton
                onClick={() => doc.route ? handleItemClick(doc.route) : navigate('/')}
                selected={currentPage === doc.route}
                sx={{
                  borderRadius: 1,
                  mb: 0.5
                }}
              >
                <ListItemIcon sx={{
                  color: currentPage === doc.route ? 'primary.main' : 'text.secondary',
                  minWidth: 40
                }}>
                  {getDocumentIcon(doc.title)}
                </ListItemIcon>
                <ListItemText
                  primary={doc.title}
                  slotProps={{
                    primary: {
                      fontWeight: currentPage === doc.route ? 'medium' : 'regular',
                    }
                  }}
                />
              </ListItemButton>
            </ListItem>
          ))}
        </List>
      </Box>
    </Box>
  );
};

const getDocumentIcon = (title: string): React.ReactNode => {
  const item = documents.find(d => d.title.toLocaleLowerCase() === title.toLocaleLowerCase());
  if (!item) {
    throw Error(`${title} does not exist in documents`);
  }
  return item.icon || <ViewQuiltIcon />;
}

type DocType = {
  title: string;
  route: string | null;
  description: string;
  icon?: React.ReactNode;
};

const documents : DocType[] = [
  { title: "Backstory", route: null, description: "Backstory", icon: <ArrowBackIcon /> },
  { title: "About", route: "about", description: "General information about the application and its purpose", icon: <DescriptionIcon /> },
  { title: "BETA", route: "beta", description: "Details about the current beta version and upcoming features", icon: <CodeIcon /> },
  { title: "Resume Generation Architecture", route: "resume-generation", description: "Technical overview of how resumes are processed and generated", icon: <LayersIcon /> },
  { title: "Application Architecture", route: "about-app", description: "System design and technical stack information", icon: <LayersIcon /> },
  { title: "Authentication Architecture", route: "authentication.md", description: "Complete authentication architecture", icon: <LayersIcon /> },
  { title: "UI Overview", route: "ui-overview", description: "Guide to the user interface components and interactions", icon: <DashboardIcon /> },
  { title: "UI Mockup", route: "ui-mockup", description: "Visual previews of interfaces and layout concepts", icon: <DashboardIcon /> },
  { title: "Theme Visualizer", route: "theme-visualizer", description: "Explore and customize application themes and visual styles", icon: <PaletteIcon /> },
  { title: "App Analysis", route: "app-analysis", description: "Statistics and performance metrics of the application", icon: <AnalyticsIcon /> },
  { title: 'Text Mockups', route: "backstory-ui-mockups", description: "Early text mockups of many of the interaction points." },
  { title: 'User Management', route: "user-management", description: "User management.", icon: <PersonIcon /> },
  { title: 'Type Safety', route: "type-safety", description: "Overview of front/back-end type synchronization.", icon: <CodeIcon /> },
];

const documentFromRoute = (route: string) : DocType | null => {
  const index = documents.findIndex(v => v.route === route);
  if (index === -1) {
    return null 
  }
  return documents[index];
};

// Helper function to get document title from route
const documentTitleFromRoute = (route: string): string => {
  const doc = documentFromRoute(route);
  if (doc === null) {
    return 'Documentation'
  }
  return doc.title;
}

const DocsPage = (props: BackstoryPageProps) => {
  const { setSnack } = useAppState();
  const navigate = useNavigate();
  const location = useLocation();
  const { paramPage = '' } = useParams();
  const [page, setPage] = useState<string>(paramPage);
  const [drawerOpen, setDrawerOpen] = useState(false);

  const theme = useTheme();
  const isMobile = useMediaQuery(theme.breakpoints.down('md'));

  // Track location changes
  useEffect(() => {
    const parts = location.pathname.split('/');
    if (parts.length > 2) {
      setPage(parts[2]);
    } else {
      setPage('');
    }
  }, [location]);

  // Close drawer when changing to desktop view
  useEffect(() => {
    if (!isMobile) {
      setDrawerOpen(false);
    }
  }, [isMobile]);

  // Handle document navigation
  const onDocumentExpand = (docName: string, open: boolean) => {
    console.log("Document expanded:", { docName, open, location });
    if (open) {
      const parts = location.pathname.split('/');
      if (docName === "backstory") {
        navigate('/');
        return;
      }
      if (parts.length > 2) {
        const basePath = parts.slice(0, -1).join('/');
        navigate(`${basePath}/${docName}`);
      } else {
        navigate(docName);
      }
    } else {
      const basePath = location.pathname.split('/').slice(0, -1).join('/');
      navigate(`${basePath}`);
    }
  };

  // Toggle mobile drawer
  const toggleDrawer = () => {
    setDrawerOpen(!drawerOpen);
  };

  // Close the drawer
  const closeDrawer = () => {
    setDrawerOpen(false);
  };

  interface DocViewProps {
    page: string
  };
  const DocView = (props: DocViewProps) => {
    const { page = 'about' } = props;
    const title = documentTitleFromRoute(page);
    const icon = getDocumentIcon(title);

    return (
      <Card>
        <CardContent>
          <Box sx={{ color: 'inherit', fontSize: "1.75rem", fontWeight: "bold", display: "flex", flexDirection: "row", gap: 1, alignItems: "center", mr: 1.5 }}>
            {icon}
            {title}
          </Box>
          {page && <Document
            filepath={`/docs/${page}.md`}
          />}
        </CardContent>
      </Card>
    );
  };

  // Render the appropriate content based on current page
  function renderContent() {
    switch (page) {
      case 'ui-overview':
        return (<BackstoryUIOverviewPage />);
      case 'theme-visualizer':
        return (<Paper sx={{ m: 0, p: 1 }}><BackstoryThemeVisualizerPage /></Paper>);
      case 'app-analysis':
        return (<BackstoryAppAnalysisPage />);
      case 'ui-mockup':
        return (<MockupPage />);
      case 'user-management':
        return (<UserManagement />);
      default:
        if (documentFromRoute(page)) {
          return <DocView page={page}/>
        }
        // Document grid for landing page
        return (
          <Paper sx={{ p: 1 }} elevation={0}>
            <Box sx={{ mb: 2 }}>
              <Typography variant="h4" component="h1" gutterBottom>
                Documentation
              </Typography>
              <Typography variant="body1" color="text.secondary">
                Select a document from the sidebar to view detailed technical information about the application.
              </Typography>
            </Box>
            <Grid container spacing={1}>
              {documents.map((doc, index) => {
                if (doc.route === null) return (<></>);
                return (<Grid sx={{ minWidth: "164px" }} size={{ xs: 12, sm: 6, md: 4 }} key={index}>
                  <Card sx={{ minHeight: "180px" }}>
                    <CardActionArea onClick={() => doc.route ? onDocumentExpand(doc.route, true) : navigate('/')}>
                      <CardContent sx={{ display: "flex", flexDirection: "column", m: 0, p: 1 }}>
                        <Box sx={{ display: 'flex', flexDirection: "row", gap: 1, verticalAlign: 'top' }}>
                          {getDocumentIcon(doc.title)}
                          <Typography variant="h3" sx={{ m: "0 !important" }}>{doc.title}</Typography>
                        </Box>
                        <Typography variant="body2" color="text.secondary">
                          {doc.description}
                        </Typography>
                      </CardContent>
                    </CardActionArea>
                  </Card>
                </Grid>
                )
              })}
            </Grid>
          </Paper>
        );
    }
  }

  // Calculate drawer width
  const drawerWidth = 240;

  return (
    <Box sx={{ display: 'flex', height: '100%' }}>
      {/* Mobile App Bar */}
      {isMobile && (
        <AppBar
          position="fixed"
          sx={{
            width: { sm: `calc(100% - ${drawerWidth}px)` },
            ml: { sm: `${drawerWidth}px` },
            display: { md: 'none' }
          }}
          elevation={0}
          color="default"
        >
          <Toolbar>
            <IconButton
              aria-label="open drawer"
              edge="start"
              onClick={toggleDrawer}
              sx={{ mr: 2 }}
            >
              <MenuIcon />
            </IconButton>
            <Typography variant="h6" noWrap component="div" sx={{ color: "white" }}>
              {page ? documentTitleFromRoute(page) : "Documentation"}
            </Typography>
          </Toolbar>
        </AppBar>
      )}

      {/* Navigation drawer */}
      <Box
        component="nav"
        sx={{
          width: { md: drawerWidth },
          flexShrink: { md: 0 }
        }}
      >
        {/* Mobile drawer (temporary) */}
        {isMobile ? (
          <Drawer
            variant="temporary"
            open={drawerOpen}
            onClose={closeDrawer}
            ModalProps={{
              keepMounted: true, // Better open performance on mobile
            }}
            sx={{
              display: { xs: 'block', md: 'none' },
              '& .MuiDrawer-paper': {
                boxSizing: 'border-box',
                width: drawerWidth
              },
            }}
          >
            <Sidebar
              currentPage={page}
              onDocumentSelect={onDocumentExpand}
              onClose={closeDrawer}
              isMobile={true}
            />
          </Drawer>
        ) : (
          // Desktop drawer (permanent)
          <Drawer
            variant="permanent"
            sx={{
              display: { xs: 'none', md: 'block' },
              '& .MuiDrawer-paper': {
                boxSizing: 'border-box',
                width: drawerWidth,
                position: 'relative',
                height: '100%'
              },
            }}
            open
          >
            <Sidebar
              currentPage={page}
              onDocumentSelect={onDocumentExpand}
              isMobile={false}
            />
          </Drawer>
        )}
      </Box>

      {/* Main content */}
      <Box
        component="main"
        sx={{
          flexGrow: 1,
          p: 3,
          width: { md: `calc(100% - ${drawerWidth}px)` },
          pt: isMobile ? { xs: 8, sm: 9 } : 3, // Add padding top on mobile to account for AppBar
          height: '100%',
          overflow: 'auto'
        }}
      >
        {renderContent()}
      </Box>
    </Box>
  );
};

export { DocsPage };