import { useState, type ReactNode } from "react";
import { useNavigate, useParams } from "react-router";
import {
  Alert,
  Box,
  Button,
  Chip,
  CircularProgress,
  Dialog,
  DialogActions,
  DialogContent,
  DialogTitle,
  Paper,
  Stack,
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableRow,
  TextField,
  Typography,
} from "@mui/material";
import { useApproveUplift, useDenyUplift } from "@/domain/uplifts/use-cases/use-uplift-actions";
import { useVendorPoDetail } from "@/domain/vendor-pos/use-cases/use-vendor-po-detail";
import type { UpliftRequest } from "@/domain/uplifts/types/uplift";
import { formatDateTime, toDateInputValue } from "@/lib/time-utils";

function formatMoney(value: number | null | undefined): string {
  if (value == null) return "—";
  return `$${Number(value).toFixed(2)}`;
}

function InfoRow({ label, children }: { label: string; children: ReactNode }) {
  return (
    <Box>
      <Typography variant="caption" color="text.secondary" sx={{ display: "block" }}>
        {label}
      </Typography>
      <Typography variant="body2">
        {children == null || children === "" ? "—" : children}
      </Typography>
    </Box>
  );
}

export default function VendorPoViewPage() {
  const { id } = useParams();
  const navigate = useNavigate();
  const { data: dispatch, isLoading, error, refetch } = useVendorPoDetail(id);

  const approveUplift = useApproveUplift(id);
  const denyUplift = useDenyUplift(id);

  const [upliftAction, setUpliftAction] = useState<{
    type: "approve" | "deny";
    uplift: UpliftRequest;
  } | null>(null);
  const [note, setNote] = useState("");

  const handleUpliftConfirm = () => {
    if (!upliftAction) return;
    if (upliftAction.type === "approve") {
      approveUplift.mutate(
        { id: upliftAction.uplift.id, note: note || undefined },
        {
          onSuccess: () => {
            setUpliftAction(null);
            setNote("");
            void refetch();
          },
        },
      );
    } else {
      if (!note.trim()) return;
      denyUplift.mutate(
        { id: upliftAction.uplift.id, note: note.trim() },
        {
          onSuccess: () => {
            setUpliftAction(null);
            setNote("");
            void refetch();
          },
        },
      );
    }
  };

  if (isLoading) {
    return (
      <Box className="flex justify-center p-10">
        <CircularProgress />
      </Box>
    );
  }

  if (error || !dispatch) {
    return (
      <Box className="p-4">
        <Alert severity="error">
          {error instanceof Error ? error.message : "Vendor PO not found"}
        </Alert>
      </Box>
    );
  }

  const vendor = dispatch.vendor;

  return (
    <Box className="mx-auto max-w-5xl p-4">
      <Stack
        direction="row"
        className="mb-4"
        sx={{ justifyContent: "space-between", alignItems: "center" }}
      >
        <Button variant="text" onClick={() => navigate(-1)}>
          ← Back
        </Button>
        <Button variant="outlined" onClick={() => window.print()}>
          Print
        </Button>
      </Stack>

      <Stack spacing={1} className="mb-4">
        <Typography variant="h5">{dispatch.poNumber || "(no PO #)"}</Typography>
        <Stack direction="row" spacing={1} sx={{ alignItems: "center", flexWrap: "wrap" }}>
          <Typography variant="body2" color="text.secondary">
            Dispatch {dispatch.dispatchNumber || "—"}
          </Typography>
          <Chip size="small" label={dispatch.status || "—"} />
          {vendor?.companyName && (
            <Typography variant="body2" color="text.secondary">
              · {vendor.companyName}
            </Typography>
          )}
          {dispatch.nteAmount != null && (
            <Typography variant="body2" color="text.secondary">
              · NTE {formatMoney(dispatch.nteAmount)}
            </Typography>
          )}
        </Stack>
      </Stack>

      <Stack spacing={3}>
        <Paper variant="outlined" className="p-4">
          <Typography variant="subtitle1" className="mb-3 font-semibold">
            Vendor
          </Typography>
          {vendor ? (
            <Box className="grid grid-cols-1 gap-3 sm:grid-cols-2 md:grid-cols-3">
              <InfoRow label="Company">{vendor.companyName}</InfoRow>
              <InfoRow label="Contact">{vendor.contactName}</InfoRow>
              <InfoRow label="Email">{vendor.email}</InfoRow>
              <InfoRow label="Phone">{vendor.phone}</InfoRow>
              <InfoRow label="Address">
                {[vendor.address, vendor.city, vendor.state, vendor.zip].filter(Boolean).join(", ")}
              </InfoRow>
              <InfoRow label="Trades">{vendor.tradeSpecialties}</InfoRow>
            </Box>
          ) : (
            <Typography color="text.secondary">No vendor attached.</Typography>
          )}
        </Paper>

        <Paper variant="outlined" className="p-4">
          <Typography variant="subtitle1" className="mb-3 font-semibold">
            PO Details
          </Typography>
          <Box className="grid grid-cols-1 gap-3 sm:grid-cols-2 md:grid-cols-3">
            <InfoRow label="PO #">{dispatch.poNumber}</InfoRow>
            <InfoRow label="Dispatch #">{dispatch.dispatchNumber}</InfoRow>
            <InfoRow label="Status">{dispatch.status}</InfoRow>
            <InfoRow label="NTE">{formatMoney(dispatch.nteAmount)}</InfoRow>
            <InfoRow label="Dispatched">{formatDateTime(dispatch.dispatchedAt)}</InfoRow>
            <InfoRow label="Acknowledged">{formatDateTime(dispatch.acknowledgedAt)}</InfoRow>
            <InfoRow label="Scheduled">{toDateInputValue(dispatch.scheduledDate) || "—"}</InfoRow>
            <InfoRow label="Completed">{toDateInputValue(dispatch.completedDate) || "—"}</InfoRow>
            <InfoRow label="Verified">{formatDateTime(dispatch.verifiedAt)}</InfoRow>
            <InfoRow label="Email sent">{dispatch.emailSent ? "Yes" : "No"}</InfoRow>
          </Box>
          {dispatch.description && (
            <Box className="mt-3">
              <Typography variant="caption" color="text.secondary">
                Description
              </Typography>
              <Typography variant="body2" className="whitespace-pre-wrap">
                {dispatch.description}
              </Typography>
            </Box>
          )}
        </Paper>

        {dispatch.primaryLocation && (
          <Paper variant="outlined" className="p-4">
            <Typography variant="subtitle1" className="mb-3 font-semibold">
              Site
            </Typography>
            <Box className="grid grid-cols-1 gap-3 sm:grid-cols-2">
              <InfoRow label="Location">{dispatch.primaryLocation.name}</InfoRow>
              <InfoRow label="Address">
                {[
                  dispatch.primaryLocation.address,
                  dispatch.primaryLocation.city,
                  dispatch.primaryLocation.state,
                  dispatch.primaryLocation.zipCode,
                ]
                  .filter(Boolean)
                  .join(", ")}
              </InfoRow>
            </Box>
          </Paper>
        )}

        <Paper variant="outlined" className="p-4">
          <Typography variant="subtitle1" className="mb-3 font-semibold">
            Linked Work Orders ({dispatch.workOrders.length})
          </Typography>
          {dispatch.workOrders.length === 0 ? (
            <Typography color="text.secondary">No work orders linked.</Typography>
          ) : (
            <Table size="small">
              <TableHead>
                <TableRow>
                  <TableCell>WO #</TableCell>
                  <TableCell>Title</TableCell>
                  <TableCell>Trade</TableCell>
                  <TableCell>Status</TableCell>
                  <TableCell>Location</TableCell>
                </TableRow>
              </TableHead>
              <TableBody>
                {dispatch.workOrders.map((wo) => (
                  <TableRow key={String(wo.workOrderId)}>
                    <TableCell>
                      <Button
                        variant="text"
                        size="small"
                        onClick={() => navigate(`/workorders/${wo.workOrderId}`)}
                      >
                        {wo.internalWONumber || wo.workOrderId}
                      </Button>
                    </TableCell>
                    <TableCell>{wo.title}</TableCell>
                    <TableCell>{wo.trade}</TableCell>
                    <TableCell>{wo.status}</TableCell>
                    <TableCell>{wo.locationName}</TableCell>
                  </TableRow>
                ))}
              </TableBody>
            </Table>
          )}
        </Paper>

        <Paper variant="outlined" className="p-4">
          <Typography variant="subtitle1" className="mb-3 font-semibold">
            NTE Uplift History ({dispatch.upliftRequests.length})
          </Typography>
          {dispatch.upliftRequests.length === 0 ? (
            <Typography color="text.secondary">No uplift requests on this PO.</Typography>
          ) : (
            <Stack spacing={2}>
              {dispatch.upliftRequests.map((u) => (
                <Box key={String(u.id)} className="rounded border border-border p-3">
                  <Stack
                    direction="row"
                    sx={{ justifyContent: "space-between", alignItems: "center" }}
                  >
                    <Typography variant="body2" className="font-semibold">
                      {formatMoney(u.currentNTE)} → {formatMoney(u.requestedNTE)}
                      <Typography
                        component="span"
                        variant="caption"
                        color="text.secondary"
                        className="ml-2"
                      >
                        (Δ {formatMoney(u.delta)}, Tier {u.requiredTier})
                      </Typography>
                    </Typography>
                    <Chip size="small" label={u.status} />
                  </Stack>
                  {u.vendorReason && (
                    <Typography variant="body2" className="mt-1">
                      <strong>Reason:</strong> {u.vendorReason}
                    </Typography>
                  )}
                  {u.status === "Pending" && (
                    <Stack direction="row" spacing={1} className="mt-2">
                      <Button
                        size="small"
                        variant="contained"
                        color="success"
                        onClick={() => {
                          setUpliftAction({ type: "approve", uplift: u });
                          setNote("");
                        }}
                      >
                        Approve
                      </Button>
                      <Button
                        size="small"
                        variant="contained"
                        color="error"
                        onClick={() => {
                          setUpliftAction({ type: "deny", uplift: u });
                          setNote("");
                        }}
                      >
                        Deny
                      </Button>
                    </Stack>
                  )}
                </Box>
              ))}
            </Stack>
          )}
        </Paper>
      </Stack>

      <Dialog open={Boolean(upliftAction)} onClose={() => setUpliftAction(null)}>
        <DialogTitle>
          {upliftAction?.type === "approve" ? "Approve Uplift" : "Deny Uplift"}
        </DialogTitle>
        <DialogContent>
          <TextField
            fullWidth
            multiline
            minRows={2}
            className="mt-2"
            label={upliftAction?.type === "deny" ? "Denial reason (required)" : "Optional note"}
            value={note}
            onChange={(e) => setNote(e.target.value)}
            required={upliftAction?.type === "deny"}
          />
        </DialogContent>
        <DialogActions>
          <Button onClick={() => setUpliftAction(null)}>Cancel</Button>
          <Button
            variant="contained"
            color={upliftAction?.type === "approve" ? "success" : "error"}
            disabled={
              upliftAction?.type === "deny"
                ? !note.trim() || denyUplift.isPending
                : approveUplift.isPending
            }
            onClick={handleUpliftConfirm}
          >
            Confirm
          </Button>
        </DialogActions>
      </Dialog>
    </Box>
  );
}