import React, { useState, useEffect } from 'react';
import { 
  Box, 
  Stepper, 
  Step, 
  StepLabel, 
  Button, 
  Typography, 
  Paper, 
  TextField, 
  Grid,
  Card,
  CardContent,
  CardActionArea,
  Avatar,
  Divider,
  CircularProgress,
  Container,
  useTheme,
  Snackbar,
  Alert,
  Dialog,
  DialogTitle,
  DialogContent,
  DialogContentText,
  DialogActions,
  InputAdornment,
  IconButton
} from '@mui/material';
import SearchIcon from '@mui/icons-material/Search';
import PersonIcon from '@mui/icons-material/Person';
import WorkIcon from '@mui/icons-material/Work';
import AssessmentIcon from '@mui/icons-material/Assessment';
import DescriptionIcon from '@mui/icons-material/Description';
import FileUploadIcon from '@mui/icons-material/FileUpload';
import { JobMatchAnalysis } from 'components/JobMatchAnalysis';
import { Candidate } from "types/types";
import { useNavigate } from 'react-router-dom';
import { BackstoryPageProps } from 'components/BackstoryTab';
import { useAuth } from 'hooks/AuthContext';
import { useSelectedCandidate } from 'hooks/GlobalContext';
import { CandidateInfo } from 'components/CandidateInfo';
import { ComingSoon } from 'components/ui/ComingSoon';

// Main component
const JobAnalysisPage: React.FC<BackstoryPageProps> = (props: BackstoryPageProps) => {
  const theme = useTheme();
  const { user } = useAuth();
  const { selectedCandidate, setSelectedCandidate } = useSelectedCandidate()
  const { setSnack, submitQuery } = props;
  const backstoryProps = { setSnack, submitQuery };
  // State management
  const [activeStep, setActiveStep] = useState(0);
  const [jobDescription, setJobDescription] = useState('');
  const [jobTitle, setJobTitle] = useState('');
  const [jobLocation, setJobLocation] = useState('');
  const [analysisStarted, setAnalysisStarted] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [openUploadDialog, setOpenUploadDialog] = useState(false);
  const { apiClient } = useAuth();
  const [candidates, setCandidates] = useState<Candidate[] | null>(null);

  useEffect(() => {
    if (candidates !== null || selectedCandidate) {
      return;
    }
    const getCandidates = async () => {
      try {
        const results = await apiClient.getCandidates();
        const candidates: Candidate[] = results.data;
        candidates.sort((a, b) => {
          let result = a.lastName.localeCompare(b.lastName);
          if (result === 0) {
            result = a.firstName.localeCompare(b.firstName);
          }
          if (result === 0) {
            result = a.username.localeCompare(b.username);
          }
          return result;
        });
        console.log(candidates);
        setCandidates(candidates);
      } catch (err) {
        setSnack("" + err);
      }
    };

    getCandidates();
  }, [candidates, setSnack]);

  useEffect(() => {
    if (selectedCandidate && activeStep === 0) {
      setActiveStep(1);
    }
  }, [selectedCandidate, activeStep]);

  // Steps in our process
  const steps = [
    { index: 1, label: 'Job Description', icon: <WorkIcon /> },
    { index: 2, label: 'AI Analysis', icon: <WorkIcon /> },
    { index: 3, label: 'Generated Resume', icon: <AssessmentIcon /> }
  ];
  if (!selectedCandidate) {
    steps.unshift({ index: 0, label: 'Select Candidate', icon: <PersonIcon /> })
  }

  const fetchMatchForRequirement = async (requirement: string): Promise<any> => {
    // Create different mock responses based on the requirement
    const mockResponses: Record<string, any> = {
      "5+ years of React development experience": {
        requirement: "5+ years of React development experience",
        status: "complete",
        matchScore: 85,
        assessment: "The candidate demonstrates extensive React experience spanning over 6 years, with a strong portfolio of complex applications and deep understanding of React's component lifecycle and hooks.",
        citations: [
          {
            text: "Led frontend development team of 5 engineers to rebuild our customer portal using React and TypeScript, resulting in 40% improved performance and 30% reduction in bugs.",
            source: "Resume, Work Experience",
            relevance: 95
          },
          {
            text: "Developed and maintained reusable React component library used across 12 different products within the organization.",
            source: "Resume, Work Experience",
            relevance: 90
          },
          {
            text: "I've been working with React since 2017, building everything from small widgets to enterprise applications.",
            source: "Cover Letter",
            relevance: 85
          }
        ]
      },
      "Strong TypeScript skills": {
        requirement: "Strong TypeScript skills",
        status: "complete",
        matchScore: 90,
        assessment: "The candidate shows excellent TypeScript proficiency through their work history and personal projects. They have implemented complex type systems and demonstrate an understanding of advanced TypeScript features.",
        citations: [
          {
            text: "Converted a legacy JavaScript codebase of 100,000+ lines to TypeScript, implementing strict type checking and reducing runtime errors by 70%.",
            source: "Resume, Projects",
            relevance: 98
          },
          {
            text: "Created comprehensive TypeScript interfaces for our GraphQL API, ensuring type safety across the entire application stack.",
            source: "Resume, Technical Skills",
            relevance: 95
          }
        ]
      },
      "Experience with RESTful APIs": {
        requirement: "Experience with RESTful APIs",
        status: "complete",
        matchScore: 75,
        assessment: "The candidate has good experience with RESTful APIs, having both consumed and designed them. They understand REST principles but have less documented experience with API versioning and caching strategies.",
        citations: [
          {
            text: "Designed and implemented a RESTful API serving over 1M requests daily with a focus on performance and scalability.",
            source: "Resume, Technical Projects",
            relevance: 85
          },
          {
            text: "Worked extensively with third-party APIs including Stripe, Twilio, and Salesforce to integrate payment processing and communication features.",
            source: "Resume, Work Experience",
            relevance: 70
          }
        ]
      },
      "Knowledge of state management solutions (Redux, Context API)": {
        requirement: "Knowledge of state management solutions (Redux, Context API)",
        status: "complete",
        matchScore: 65,
        assessment: "The candidate has moderate experience with state management, primarily using Redux. There is less evidence of Context API usage, which could indicate a knowledge gap in more modern React state management approaches.",
        citations: [
          {
            text: "Implemented Redux for global state management in an e-commerce application, handling complex state logic for cart, user preferences, and product filtering.",
            source: "Resume, Skills",
            relevance: 80
          },
          {
            text: "My experience includes working with state management libraries like Redux and MobX.",
            source: "Cover Letter",
            relevance: 60
          }
        ]
      },
      "Experience with CI/CD pipelines": {
        requirement: "Experience with CI/CD pipelines",
        status: "complete",
        matchScore: 40,
        assessment: "The candidate shows limited experience with CI/CD pipelines. While they mention some exposure to Jenkins and GitLab CI, there is insufficient evidence of setting up or maintaining comprehensive CI/CD workflows.",
        citations: [
          {
            text: "Familiar with CI/CD tools including Jenkins and GitLab CI.",
            source: "Resume, Skills",
            relevance: 40
          }
        ]
      },
      "Cloud platform experience (AWS, Azure, GCP)": {
        requirement: "Cloud platform experience (AWS, Azure, GCP)",
        status: "complete",
        matchScore: 30,
        assessment: "The candidate demonstrates minimal experience with cloud platforms. There is a brief mention of AWS S3 and Lambda, but no substantial evidence of deeper cloud architecture knowledge or experience with Azure or GCP.",
        citations: [
          {
            text: "Used AWS S3 for file storage and Lambda for image processing in a photo sharing application.",
            source: "Resume, Projects",
            relevance: 35
          }
        ]
      }
    };
  
    // Return a promise that resolves with the mock data after a delay
    return new Promise((resolve) => {
      // Different requirements resolve at different speeds to simulate real-world analysis
      const delay = Math.random() * 5000 + 2000; // 2-7 seconds
      setTimeout(() => {
        resolve(mockResponses[requirement]);
      }, delay);
    });
  };

  // Navigation handlers
  const handleNext = () => {
    if (activeStep === 0 && !selectedCandidate) {
      setError('Please select a candidate before continuing.');
      return;
    }
    
    if (activeStep === 1) {
      if ((/*(extraInfo && !jobTitle) || */!jobDescription)) {
        setError('Please provide job description before continuing.');
        return;
      }
    }
    
    if (activeStep === 2) {
      setAnalysisStarted(true);
    }
    
    setActiveStep((prevActiveStep) => prevActiveStep + 1);
  };

  const handleBack = () => {
    setActiveStep((prevActiveStep) => prevActiveStep - 1);
  };

  const handleReset = () => {
    // setActiveStep(0);
    setActiveStep(1);
    // setSelectedCandidate(null);
    setJobDescription('');
    // setJobTitle('');
    // setJobLocation('');
    setAnalysisStarted(false);
  };

  // Render function for the candidate selection step
  const renderCandidateSelection = () => (
    <Paper elevation={3} sx={{ p: 3, mt: 3, mb: 4, borderRadius: 2 }}>
      <Typography variant="h5" gutterBottom>
        Select a Candidate
      </Typography>
      
      {/* <Box sx={{ mb: 3, display: 'flex' }}>
        <TextField
          fullWidth
          variant="outlined"
          placeholder="Search candidates by name, title, or location"
          value={searchQuery}
          onChange={(e) => setSearchQuery(e.target.value)}
          InputProps={{
            endAdornment: (
              <InputAdornment position="end">
                <IconButton onClick={handleSearch} edge="end">
                  <SearchIcon />
                </IconButton>
              </InputAdornment>
            ),
          }}
          sx={{ mr: 2 }}
        />
      </Box> */}

        <Grid container spacing={3}>
        {candidates?.map((candidate) => (
            <Grid size={{ xs: 12, sm: 6, md: 4 }} key={candidate.id}>
              <Card 
                elevation={selectedCandidate?.id === candidate.id ? 8 : 1}
                sx={{ 
                  height: '100%',
                  borderColor: selectedCandidate?.id === candidate.id ? theme.palette.primary.main : 'transparent',
                  borderWidth: 2,
                  borderStyle: 'solid',
                  transition: 'all 0.3s ease'
                }}
              >
                <CardActionArea 
                  onClick={() => setSelectedCandidate(candidate)}
                  sx={{ height: '100%', display: 'flex', flexDirection: 'column', alignItems: 'stretch' }}
                >
                  <CardContent sx={{ flexGrow: 1, p: 3 }}>
                    <Box sx={{ display: 'flex', mb: 2, alignItems: 'center' }}>
                      <Avatar 
                      src={candidate.profileImage}
                      alt={candidate.firstName}
                        sx={{ width: 64, height: 64, mr: 2 }}
                      />
                      <Box>
                        <Typography variant="h6" component="div">
                        {candidate.fullName}
                        </Typography>
                        <Typography variant="body2" color="text.secondary">
                        {candidate.description}
                        </Typography>
                      </Box>
                    </Box>
                    
                    <Divider sx={{ my: 2 }} />
                    
                  {candidate.location && <Typography variant="body2" sx={{ mb: 1 }}>
                    <strong>Location:</strong> {candidate.location.country}
                  </Typography>}
                    <Typography variant="body2" sx={{ mb: 1 }}>
                      <strong>Email:</strong> {candidate.email}
                    </Typography>
                  {candidate.phone && <Typography variant="body2">
                    <strong>Phone:</strong> {candidate.phone} 
                  </Typography>}
                  </CardContent>
                </CardActionArea>
              </Card>
            </Grid>
          ))}
      </Grid>
    </Paper>
  );

  const extraInfo = false;

  // Render function for the job description step
  const renderJobDescription = () => (
    <Paper elevation={3} sx={{ p: 3, mt: 3, mb: 4, borderRadius: 2 }}>
      {extraInfo && <>
        <Typography variant="h5" gutterBottom>
          Enter Job Details
        </Typography>

        <Grid container spacing={3}>
          <Grid size={{ xs: 12, md: 6 }}>
            <TextField
              fullWidth
              label="Job Title"
              variant="outlined"
              value={jobTitle}
              onChange={(e) => setJobTitle(e.target.value)}
              required
              margin="normal"
            />
          </Grid>

          <Grid size={{ xs: 12, md: 6 }}>
            <TextField
              fullWidth
              label="Job Location"
              variant="outlined"
              value={jobLocation}
              onChange={(e) => setJobLocation(e.target.value)}
              margin="normal"
            />
          </Grid>
        </Grid>
      </>
      }

        <Grid size={{ xs: 12 }}>
          <Box sx={{ display: 'flex', alignItems: 'center', mt: 2, mb: 1 }}>
            <Typography variant="subtitle1" sx={{ mr: 2 }}>
              Job Description
            </Typography>
          {extraInfo && <Button 
              variant="outlined" 
              startIcon={<FileUploadIcon />}
              size="small"
              onClick={() => setOpenUploadDialog(true)}
            >
              Upload
          </Button>}
          </Box>
          
          <TextField
            fullWidth
            multiline
            rows={12}
            placeholder="Enter the job description here..."
            variant="outlined"
            value={jobDescription}
            onChange={(e) => setJobDescription(e.target.value)}
            required
            InputProps={{
              startAdornment: (
                <InputAdornment position="start" sx={{ alignSelf: 'flex-start', mt: 1.5 }}>
                  <DescriptionIcon color="action" />
                </InputAdornment>
              ),
            }}
          />
          <Typography variant="caption" color="text.secondary" sx={{ mt: 1, display: 'block' }}>
            The job description will be used to extract requirements for candidate matching.
        </Typography>
      </Grid>
    </Paper>
  );

  // Render function for the analysis step
  const renderAnalysis = () => (
    <Box sx={{ mt: 3 }}>
      {selectedCandidate && (
        <JobMatchAnalysis
          job={{ title: jobTitle, description: jobDescription }}
          candidate={selectedCandidate}
          {...backstoryProps}
        />
      )}
    </Box>
  );

  const renderResume = () => (
    <Box sx={{ mt: 3 }}>
      {selectedCandidate && <ComingSoon>Resume Builder</ComingSoon>}
    </Box>
  );

  // If no user is logged in, show message
  if (!user) {
    return (
      <Container maxWidth="md">
        <Paper elevation={3} sx={{ p: 4, mt: 4, textAlign: 'center' }}>
          <Typography variant="h5" gutterBottom>
            Please log in to access candidate analysis
          </Typography>
          <Button variant="contained" color="primary" sx={{ mt: 2 }}>
            Log In
          </Button>
        </Paper>
      </Container>
    );
  }

  return (
    <Container maxWidth="lg">
      <Paper elevation={1} sx={{ p: 3, mt: 3, borderRadius: 2 }}>
        <Typography variant="h4" component="h1" gutterBottom>
          Candidate Analysis
        </Typography>
        {selectedCandidate && <CandidateInfo variant="small" candidate={selectedCandidate} />}
        <Typography variant="subtitle1" color="text.secondary" gutterBottom>
          Match candidates to job requirements with AI-powered analysis
        </Typography>
      </Paper>
      
      <Box sx={{ mt: 4, mb: 4 }}>
        <Stepper activeStep={activeStep} alternativeLabel>
          {steps.map(step => (
            <Step key={step.index}>
              <StepLabel slots={{
                stepIcon: () => (
                <Avatar 
                  sx={{ 
                      bgcolor: activeStep >= step.index ? theme.palette.primary.main : theme.palette.grey[300],
                    color: 'white'
                  }}
                >
                  {step.icon}
                </Avatar>
                )
              }}
              >
                {step.label}
              </StepLabel>
            </Step>
          ))}
        </Stepper>
      </Box>
      
      {activeStep === 0 && renderCandidateSelection()}
      {activeStep === 1 && renderJobDescription()}
      {activeStep === 2 && renderAnalysis()}
      {activeStep === 3 && renderResume()}
      
      <Box sx={{ display: 'flex', flexDirection: 'row', pt: 2 }}>
        <Button
          color="inherit"
          disabled={activeStep === steps[0].index}
          onClick={handleBack}
          sx={{ mr: 1 }}
        >
          Back
        </Button>
        <Box sx={{ flex: '1 1 auto' }} />
        
        {activeStep === steps[steps.length - 1].index ? (
          <Button onClick={handleReset} variant="outlined">
            Start New Analysis
          </Button>
        ) : (
          <Button onClick={handleNext} variant="contained">
              {activeStep === steps[steps.length - 1].index - 1 ? 'Start Analysis' : 'Next'}
          </Button>
        )}
      </Box>
      
      {/* Error Snackbar */}
      <Snackbar
        open={!!error}
        autoHideDuration={6000}
        onClose={() => setError(null)}
        anchorOrigin={{ vertical: 'bottom', horizontal: 'center' }}
      >
        <Alert onClose={() => setError(null)} severity="error" sx={{ width: '100%' }}>
          {error}
        </Alert>
      </Snackbar>
      
      {/* Upload Dialog */}
      <Dialog open={openUploadDialog} onClose={() => setOpenUploadDialog(false)}>
        <DialogTitle>Upload Job Description</DialogTitle>
        <DialogContent>
          <DialogContentText>
            Upload a job description document (.pdf, .docx, .txt, or .md)
          </DialogContentText>
          <Box sx={{ mt: 2, textAlign: 'center' }}>
            <Button
              variant="outlined"
              component="label"
              startIcon={<FileUploadIcon />}
              sx={{ mt: 1 }}
            >
              Choose File
              <input
                type="file"
                hidden
                accept=".pdf,.docx,.txt,.md"
                onChange={() => {
                  // This would handle file upload in a real application
                  setOpenUploadDialog(false);
                  // Mock setting job description from file
                  setJobDescription(
                    "Senior Frontend Developer\n\nRequired Skills:\n- 5+ years of React development experience\n- Strong TypeScript skills\n- Experience with RESTful APIs\n- Knowledge of state management solutions (Redux, Context API)\n- Experience with CI/CD pipelines\n- Cloud platform experience (AWS, Azure, GCP)\n\nResponsibilities:\n- Develop and maintain frontend applications using React and TypeScript\n- Collaborate with backend developers to integrate APIs\n- Optimize applications for maximum speed and scalability\n- Design and implement new features and functionality\n- Ensure the technical feasibility of UI/UX designs"
                  );
                  setJobTitle("Senior Frontend Developer");
                  setJobLocation("Remote");
                }}
              />
            </Button>
          </Box>
        </DialogContent>
        <DialogActions>
          <Button onClick={() => setOpenUploadDialog(false)}>Cancel</Button>
        </DialogActions>
      </Dialog>
    </Container>
  );
};

export { JobAnalysisPage };