import DownloadIcon from "@mui/icons-material/Download";
import TableChartIcon from "@mui/icons-material/TableChart";
import {
  Box,
  Button,
  Card,
  CardContent,
  CardHeader,
  CircularProgress,
  Divider,
  Grid,
  MenuItem,
  Stack,
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableRow,
  TextField,
  ToggleButton,
  Typography,
} from "@mui/material";
import { useState } from "react";
import {
  Bar,
  BarChart,
  CartesianGrid,
  Legend,
  ResponsiveContainer,
  Tooltip,
  XAxis,
  YAxis,
} from "recharts";
import { useLookups, useReportsSummary } from "../api/hooks";

/* Validated categorical palette (dataviz reference instance, light mode).
 * Fixed slot order — color follows the entity: labor=1 material=2 service=3
 * other=4. Aqua/yellow sit below 3:1 on white, so the cost chart ships a
 * table view (relief rule). */
const SERIES = {
  labor: "#2a78d6",
  material: "#1baf7a",
  service: "#eda100",
  other: "#008300",
};
const SINGLE_HUE = "#2a78d6";
const GRID = "#eceff1";
const TICK = { fill: "#52514e", fontSize: 12 };

function money(n: number): string {
  return n.toLocaleString(undefined, {
    style: "currency",
    currency: "USD",
    maximumFractionDigits: 0,
  });
}

function csvDownload(filename: string, rows: Record<string, unknown>[]): void {
  if (rows.length === 0) return;
  const headers = Object.keys(rows[0]);
  const esc = (v: unknown) => `"${String(v ?? "").replace(/"/g, '""')}"`;
  const csv = [
    headers.join(","),
    ...rows.map((r) => headers.map((h) => esc(r[h])).join(",")),
  ].join("\n");
  const url = URL.createObjectURL(new Blob([csv], { type: "text/csv" }));
  const a = document.createElement("a");
  a.href = url;
  a.download = filename;
  a.click();
  setTimeout(() => URL.revokeObjectURL(url), 30_000);
}

function StatTile({ label, value }: { label: string; value: string }) {
  return (
    <Card sx={{ flexGrow: 1, minWidth: 150 }}>
      <CardContent sx={{ py: 1.5, "&:last-child": { pb: 1.5 } }}>
        <Typography variant="caption" color="text.secondary">
          {label}
        </Typography>
        <Typography variant="h5">{value}</Typography>
      </CardContent>
    </Card>
  );
}

function ChartCard({
  title,
  subheader,
  action,
  children,
}: {
  title: string;
  subheader?: string;
  action?: React.ReactNode;
  children: React.ReactNode;
}) {
  return (
    <Card sx={{ height: "100%" }}>
      <CardHeader
        title={title}
        subheader={subheader}
        action={action}
        titleTypographyProps={{ variant: "subtitle1", fontWeight: 700 }}
        subheaderTypographyProps={{ variant: "caption" }}
      />
      <Divider />
      <CardContent>{children}</CardContent>
    </Card>
  );
}

export function ReportsPage() {
  const lookups = useLookups();
  const [dateFrom, setDateFrom] = useState("");
  const [dateTo, setDateTo] = useState("");
  const [departmentId, setDepartmentId] = useState<number | "">("");
  const [categoryId, setCategoryId] = useState<number | "">("");
  const [costAsTable, setCostAsTable] = useState(false);

  const summary = useReportsSummary({
    date_from: dateFrom || undefined,
    date_to: dateTo || undefined,
    department_id: departmentId || undefined,
    category_id: categoryId || undefined,
  });

  const data = summary.data;
  const costRows = (data?.cost_over_time ?? []).map((c) => ({
    month: c.month,
    Labor: Number(c.labor),
    Material: Number(c.material),
    Service: Number(c.service),
    Other: Number(c.other),
    Total: Number(c.total),
  }));

  return (
    <Box>
      <Typography variant="h5" gutterBottom>
        Reports
      </Typography>

      {/* Filters — one row above the charts */}
      <Card sx={{ mb: 2 }}>
        <CardContent sx={{ py: 1.5, "&:last-child": { pb: 1.5 } }}>
          <Stack direction={{ xs: "column", sm: "row" }} spacing={1.5}>
            <TextField
              size="small"
              type="date"
              label="From"
              InputLabelProps={{ shrink: true }}
              value={dateFrom}
              onChange={(e) => setDateFrom(e.target.value)}
            />
            <TextField
              size="small"
              type="date"
              label="To"
              InputLabelProps={{ shrink: true }}
              value={dateTo}
              onChange={(e) => setDateTo(e.target.value)}
            />
            <TextField
              size="small"
              select
              label="Department"
              value={departmentId}
              onChange={(e) =>
                setDepartmentId(e.target.value === "" ? "" : Number(e.target.value))
              }
              sx={{ minWidth: 180 }}
            >
              <MenuItem value="">All departments</MenuItem>
              {(lookups.data?.departments ?? []).map((d) => (
                <MenuItem key={d.id} value={d.id}>
                  {d.name}
                </MenuItem>
              ))}
            </TextField>
            <TextField
              size="small"
              select
              label="Category"
              value={categoryId}
              onChange={(e) =>
                setCategoryId(e.target.value === "" ? "" : Number(e.target.value))
              }
              sx={{ minWidth: 180 }}
            >
              <MenuItem value="">All categories</MenuItem>
              {(lookups.data?.deviation_categories ?? []).map((c) => (
                <MenuItem key={c.id} value={c.id}>
                  {c.name}
                </MenuItem>
              ))}
            </TextField>
          </Stack>
        </CardContent>
      </Card>

      {summary.isLoading || !data ? (
        <Box sx={{ textAlign: "center", py: 8 }}>
          <CircularProgress />
        </Box>
      ) : (
        <>
          <Stack direction="row" spacing={1.5} sx={{ mb: 2 }} flexWrap="wrap" useFlexGap>
            <StatTile label="Total NCRs" value={String(data.total_ncrs)} />
            <StatTile label="Open" value={String(data.open_ncrs)} />
            <StatTile label="Closed" value={String(data.closed_ncrs)} />
            <StatTile label="Cost of Nonconformance" value={money(Number(data.total_cost))} />
            <StatTile
              label="Avg End-to-End"
              value={
                data.end_to_end_avg_days !== null
                  ? `${data.end_to_end_avg_days} days`
                  : "—"
              }
            />
          </Stack>

          <Grid container spacing={2}>
            <Grid item xs={12} md={6}>
              <ChartCard title="NCRs by Month">
                <ResponsiveContainer width="100%" height={260}>
                  <BarChart data={data.by_month}>
                    <CartesianGrid stroke={GRID} vertical={false} />
                    <XAxis dataKey="month" tick={TICK} tickLine={false} />
                    <YAxis allowDecimals={false} tick={TICK} tickLine={false} axisLine={false} />
                    <Tooltip />
                    <Bar dataKey="count" name="NCRs" fill={SINGLE_HUE} radius={[4, 4, 0, 0]} />
                  </BarChart>
                </ResponsiveContainer>
              </ChartCard>
            </Grid>

            <Grid item xs={12} md={6}>
              <ChartCard
                title="Cost of Nonconformance Over Time"
                subheader="Closed NCRs, by month closed"
                action={
                  <Stack direction="row" spacing={0.5}>
                    <ToggleButton
                      value="table"
                      size="small"
                      selected={costAsTable}
                      onChange={() => setCostAsTable(!costAsTable)}
                      title="Toggle table view"
                    >
                      <TableChartIcon fontSize="small" />
                    </ToggleButton>
                    <Button
                      size="small"
                      startIcon={<DownloadIcon />}
                      onClick={() => csvDownload("cost-of-nonconformance.csv", costRows)}
                    >
                      CSV
                    </Button>
                  </Stack>
                }
              >
                {costAsTable ? (
                  <Table size="small">
                    <TableHead>
                      <TableRow>
                        <TableCell>Month</TableCell>
                        <TableCell align="right">Labor</TableCell>
                        <TableCell align="right">Material</TableCell>
                        <TableCell align="right">Service</TableCell>
                        <TableCell align="right">Other</TableCell>
                        <TableCell align="right">Total</TableCell>
                      </TableRow>
                    </TableHead>
                    <TableBody>
                      {costRows.map((r) => (
                        <TableRow key={r.month}>
                          <TableCell>{r.month}</TableCell>
                          <TableCell align="right">{money(r.Labor)}</TableCell>
                          <TableCell align="right">{money(r.Material)}</TableCell>
                          <TableCell align="right">{money(r.Service)}</TableCell>
                          <TableCell align="right">{money(r.Other)}</TableCell>
                          <TableCell align="right" sx={{ fontWeight: 700 }}>
                            {money(r.Total)}
                          </TableCell>
                        </TableRow>
                      ))}
                    </TableBody>
                  </Table>
                ) : (
                  <ResponsiveContainer width="100%" height={260}>
                    <BarChart data={costRows}>
                      <CartesianGrid stroke={GRID} vertical={false} />
                      <XAxis dataKey="month" tick={TICK} tickLine={false} />
                      <YAxis
                        tick={TICK}
                        tickLine={false}
                        axisLine={false}
                        tickFormatter={(v: number) => money(v)}
                        width={72}
                      />
                      <Tooltip formatter={(v: number) => money(v)} />
                      <Legend />
                      {/* 2px surface gap between stacked segments via stroke */}
                      <Bar dataKey="Labor" stackId="cost" fill={SERIES.labor} stroke="#fff" strokeWidth={1} />
                      <Bar dataKey="Material" stackId="cost" fill={SERIES.material} stroke="#fff" strokeWidth={1} />
                      <Bar dataKey="Service" stackId="cost" fill={SERIES.service} stroke="#fff" strokeWidth={1} />
                      <Bar dataKey="Other" stackId="cost" fill={SERIES.other} stroke="#fff" strokeWidth={1} radius={[4, 4, 0, 0]} />
                    </BarChart>
                  </ResponsiveContainer>
                )}
              </ChartCard>
            </Grid>

            <Grid item xs={12} md={6}>
              <ChartCard title="NCRs by Department">
                <ResponsiveContainer width="100%" height={Math.max(200, data.by_department.length * 34)}>
                  <BarChart data={data.by_department} layout="vertical">
                    <CartesianGrid stroke={GRID} horizontal={false} />
                    <XAxis type="number" allowDecimals={false} tick={TICK} tickLine={false} />
                    <YAxis type="category" dataKey="name" width={130} tick={TICK} tickLine={false} axisLine={false} />
                    <Tooltip />
                    <Bar dataKey="count" name="NCRs" fill={SINGLE_HUE} radius={[0, 4, 4, 0]} />
                  </BarChart>
                </ResponsiveContainer>
              </ChartCard>
            </Grid>

            <Grid item xs={12} md={6}>
              <ChartCard title="NCRs by Deviation Category">
                <ResponsiveContainer width="100%" height={Math.max(200, data.by_category.length * 34)}>
                  <BarChart data={data.by_category} layout="vertical">
                    <CartesianGrid stroke={GRID} horizontal={false} />
                    <XAxis type="number" allowDecimals={false} tick={TICK} tickLine={false} />
                    <YAxis type="category" dataKey="name" width={160} tick={TICK} tickLine={false} axisLine={false} />
                    <Tooltip />
                    <Bar dataKey="count" name="NCRs" fill={SINGLE_HUE} radius={[0, 4, 4, 0]} />
                  </BarChart>
                </ResponsiveContainer>
              </ChartCard>
            </Grid>

            <Grid item xs={12} md={6}>
              <ChartCard title="Open NCR Aging" subheader="Days in current stage">
                <ResponsiveContainer width="100%" height={240}>
                  <BarChart data={data.aging}>
                    <CartesianGrid stroke={GRID} vertical={false} />
                    <XAxis dataKey="bucket" tick={TICK} tickLine={false} />
                    <YAxis allowDecimals={false} tick={TICK} tickLine={false} axisLine={false} />
                    <Tooltip />
                    <Bar dataKey="count" name="Open NCRs" fill={SINGLE_HUE} radius={[4, 4, 0, 0]} />
                  </BarChart>
                </ResponsiveContainer>
              </ChartCard>
            </Grid>

            <Grid item xs={12} md={6}>
              <ChartCard title="Average Cycle Time per Stage" subheader="Days spent in each stage">
                <ResponsiveContainer width="100%" height={240}>
                  <BarChart data={data.cycle_times} layout="vertical">
                    <CartesianGrid stroke={GRID} horizontal={false} />
                    <XAxis type="number" tick={TICK} tickLine={false} />
                    <YAxis type="category" dataKey="stage_label" width={150} tick={TICK} tickLine={false} axisLine={false} />
                    <Tooltip formatter={(v: number) => `${v} days`} />
                    <Bar dataKey="avg_days" name="Avg days" fill={SINGLE_HUE} radius={[0, 4, 4, 0]} />
                  </BarChart>
                </ResponsiveContainer>
              </ChartCard>
            </Grid>

            <Grid item xs={12} md={6}>
              <ChartCard
                title="Top Job Numbers by NCR Count"
                action={
                  <Button
                    size="small"
                    startIcon={<DownloadIcon />}
                    onClick={() => csvDownload("top-jobs.csv", data.top_jobs)}
                  >
                    CSV
                  </Button>
                }
              >
                <Table size="small">
                  <TableHead>
                    <TableRow>
                      <TableCell>Job Number</TableCell>
                      <TableCell align="right">NCRs</TableCell>
                    </TableRow>
                  </TableHead>
                  <TableBody>
                    {data.top_jobs.map((j) => (
                      <TableRow key={j.job_number}>
                        <TableCell>{j.job_number}</TableCell>
                        <TableCell align="right">{j.count}</TableCell>
                      </TableRow>
                    ))}
                    {data.top_jobs.length === 0 && (
                      <TableRow>
                        <TableCell colSpan={2}>
                          <Typography color="text.secondary">No data.</Typography>
                        </TableCell>
                      </TableRow>
                    )}
                  </TableBody>
                </Table>
              </ChartCard>
            </Grid>
          </Grid>
        </>
      )}
    </Box>
  );
}