import { useParams, useNavigate } from 'react-router-dom';
import { useQuery } from '@tanstack/react-query';
import {
  Box,
  Typography,
  Card,
  CardContent,
  Grid,
  Chip,
  Divider,
  Button,
  Skeleton,
  Stepper,
  Step,
  StepLabel,
} from '@mui/material';
import ArrowBackIcon from '@mui/icons-material/ArrowBack';
import { proposalsApi, type ProposalDetail } from '../../../lib/api/proposals';
import { STATUS_COLORS } from '../../../constants';
import { formatCurrency, formatDateTime } from '../../../lib/format';
import { useDocumentTitle } from '../../../hooks/useDocumentTitle';

const STATUS_ORDER = ['Draft', 'InReview', 'Approved', 'Sent'];

function InfoRow({ label, value }: { label: string; value: React.ReactNode }) {
  return (
    <Grid size={{ xs: 12, sm: 6, md: 4 }}>
      <Typography variant="caption" color="text.secondary">
        {label}
      </Typography>
      <Typography variant="body1">{value || '-'}</Typography>
    </Grid>
  );
}

export default function ProposalDetailPage() {
  const { id } = useParams<{ id: string }>();
  const navigate = useNavigate();

  const { data: proposal, isLoading, error } = useQuery<ProposalDetail>({
    queryKey: ['proposals', id],
    queryFn: () => proposalsApi.getById(id!),
    enabled: !!id,
  });

  useDocumentTitle(proposal?.proposalNumber ?? 'Proposal');

  if (isLoading) {
    return (
      <Box>
        <Skeleton variant="text" width={300} height={40} />
        <Skeleton variant="rectangular" height={400} sx={{ mt: 2, borderRadius: 1 }} />
      </Box>
    );
  }

  if (error || !proposal) {
    return (
      <Box>
        <Typography color="error">
          {error instanceof Error ? error.message : 'Proposal not found'}
        </Typography>
        <Button startIcon={<ArrowBackIcon />} onClick={() => navigate('/proposals')} sx={{ mt: 2 }}>
          Back to Proposals
        </Button>
      </Box>
    );
  }

  const activeStep = STATUS_ORDER.indexOf(proposal.status);

  return (
    <Box>
      <Box sx={{ display: 'flex', alignItems: 'center', gap: 2, mb: 3 }}>
        <Button startIcon={<ArrowBackIcon />} onClick={() => navigate('/proposals')}>
          Back
        </Button>
        <Typography variant="h5" sx={{ flexGrow: 1 }}>
          {proposal.proposalNumber}
        </Typography>
        <Chip
          label={proposal.status}
          color={STATUS_COLORS[proposal.status] || 'default'}
          size="medium"
        />
      </Box>

      <Card sx={{ mb: 3 }}>
        <CardContent>
          <Typography variant="subtitle2" sx={{ mb: 2 }}>
            Status Timeline
          </Typography>
          {proposal.status === 'Revised' ? (
            <Box sx={{ textAlign: 'center', py: 1 }}>
              <Chip label="Revised — a new revision has been created" color="warning" />
            </Box>
          ) : (
            <Stepper activeStep={activeStep >= 0 ? activeStep : 0} alternativeLabel>
              {STATUS_ORDER.map((label) => (
                <Step key={label} completed={STATUS_ORDER.indexOf(label) <= activeStep}>
                  <StepLabel>{label}</StepLabel>
                </Step>
              ))}
            </Stepper>
          )}
        </CardContent>
      </Card>

      <Card sx={{ mb: 3 }}>
        <CardContent>
          <Typography variant="subtitle2" sx={{ mb: 2 }}>
            Proposal Details
          </Typography>
          <Grid container spacing={2}>
            <InfoRow label="Work Order #" value={proposal.workOrderNumber} />
            <InfoRow label="Customer" value={proposal.customerName} />
            <InfoRow label="Address" value={proposal.customerAddress} />
            <InfoRow label="Category" value={proposal.serviceCategory} />
            <InfoRow label="Priority" value={proposal.priority} />
            <InfoRow label="Revision" value={`#${proposal.currentRevision}`} />
            <InfoRow label="Submitted By" value={proposal.submittedByName} />
            <InfoRow label="Submitted" value={formatDateTime(proposal.submittedAt)} />
            <InfoRow label="Bid Amount" value={formatCurrency(proposal.totalBidAmount)} />
          </Grid>

          <Divider sx={{ my: 2 }} />

          <Typography variant="caption" color="text.secondary">
            Scope of Work
          </Typography>
          <Typography variant="body1" sx={{ whiteSpace: 'pre-wrap', mt: 0.5 }}>
            {proposal.refinedScope || proposal.scopeOfWork}
          </Typography>

          {proposal.notes && (
            <>
              <Divider sx={{ my: 2 }} />
              <Typography variant="caption" color="text.secondary">
                Notes
              </Typography>
              <Typography variant="body1" sx={{ whiteSpace: 'pre-wrap', mt: 0.5 }}>
                {proposal.notes}
              </Typography>
            </>
          )}
        </CardContent>
      </Card>

      {(proposal.approvedAt || proposal.sentAt) && (
        <Card>
          <CardContent>
            <Typography variant="subtitle2" sx={{ mb: 2 }}>
              Approval & Delivery
            </Typography>
            <Grid container spacing={2}>
              <InfoRow label="Approved At" value={formatDateTime(proposal.approvedAt)} />
              <InfoRow label="Sent At" value={formatDateTime(proposal.sentAt)} />
              {proposal.vendorTotalCost !== null && (
                <InfoRow label="Vendor Cost" value={formatCurrency(proposal.vendorTotalCost)} />
              )}
            </Grid>
          </CardContent>
        </Card>
      )}
    </Box>
  );
}