import { useMemo, useState } from "react";
import { Alert, Box, CircularProgress, Stack, Tab, Tabs, Typography } from "@mui/material";
import type { GridRowParams, GridRowSelectionModel } from "@mui/x-data-grid";
import { CreatePayRunButton } from "@/dashboard/CreatePayRunButton";
import { InvoiceDataGrid } from "@/dashboard/InvoiceDataGrid";
import { allInvoicesColumns, pendingApprovalColumns, readyToPayColumns } from "@/dashboard/columns";
import { countSelectedRows } from "@/dashboard/selection";
import { useInvoices, useUpdateInvoicePayDate } from "@/domain/invoices/use-invoices";
import { areMocksEnabled, type MockInvoice } from "@/mocks";
import { useNavigate } from "@/router";

type DashboardTab = "pending" | "ready" | "all";

const emptySelection: GridRowSelectionModel = {
  type: "include",
  ids: new Set(),
};

const rowClickSx = {
  border: 1,
  borderColor: "divider",
  backgroundColor: "background.paper",
  cursor: "pointer",
} as const;

export function DashboardGrids() {
  const navigate = useNavigate();
  const [tab, setTab] = useState<DashboardTab>("pending");
  const [selection, setSelection] = useState<GridRowSelectionModel>(emptySelection);
  const { data: invoices = [], isLoading, isError, error } = useInvoices();
  const updatePayDate = useUpdateInvoicePayDate();

  const openInvoice = (params: GridRowParams<MockInvoice>) => {
    navigate("/invoices/:id", { params: { id: params.row.id } });
  };

  const pendingRows = useMemo(
    () => invoices.filter((invoice) => invoice.status === "pending_approval"),
    [invoices],
  );
  const readyRows = useMemo(
    () => invoices.filter((invoice) => invoice.status === "approved"),
    [invoices],
  );

  const selectedCount = countSelectedRows(
    selection,
    readyRows.map((invoice) => invoice.id),
  );

  const processRowUpdate = async (newRow: MockInvoice, oldRow: MockInvoice) => {
    if (newRow.payDate === oldRow.payDate) {
      return oldRow;
    }

    const nextPayDate = newRow.payDate?.trim() ? newRow.payDate.trim() : null;
    return updatePayDate.mutateAsync({ id: newRow.id, payDate: nextPayDate });
  };

  if (isLoading) {
    return (
      <Box sx={{ display: "flex", justifyContent: "center", py: 6 }}>
        <CircularProgress aria-label="Loading invoices" />
      </Box>
    );
  }

  if (isError) {
    return (
      <Alert severity="error">
        {error instanceof Error ? error.message : "Failed to load invoices"}
      </Alert>
    );
  }

  return (
    <Stack spacing={2}>
      <Tabs
        value={tab}
        onChange={(_event, value: DashboardTab) => {
          setTab(value);
          setSelection(emptySelection);
        }}
        aria-label="Invoice dashboard tabs"
      >
        <Tab
          label={`Pending Approval (${pendingRows.length})`}
          value="pending"
          data-testid="tab-pending"
        />
        <Tab label={`Ready to Pay (${readyRows.length})`} value="ready" data-testid="tab-ready" />
        <Tab label={`All Invoices (${invoices.length})`} value="all" data-testid="tab-all" />
      </Tabs>

      {tab === "pending" && (
        <InvoiceDataGrid
          data-testid="grid-pending"
          rows={pendingRows}
          columns={pendingApprovalColumns}
          onRowClick={openInvoice}
          sx={rowClickSx}
        />
      )}

      {tab === "ready" && (
        <Stack spacing={1.5}>
          <Box sx={{ display: "flex", justifyContent: "flex-end" }}>
            <CreatePayRunButton selectedCount={selectedCount} />
          </Box>
          <InvoiceDataGrid
            data-testid="grid-ready"
            rows={readyRows}
            columns={readyToPayColumns}
            checkboxSelection
            rowSelectionModel={selection}
            onRowSelectionModelChange={(model) => setSelection(model)}
            processRowUpdate={processRowUpdate}
            onProcessRowUpdateError={(processError) => {
              console.error(processError);
            }}
            sx={rowClickSx}
          />
          <Typography variant="caption" color="text.secondary">
            Double-click Pay Date to edit (ISO YYYY-MM-DD). Changes update mock state only. Open
            detail from the Invoice # link.
          </Typography>
        </Stack>
      )}

      {tab === "all" && (
        <InvoiceDataGrid
          data-testid="grid-all"
          rows={invoices}
          columns={allInvoicesColumns}
          onRowClick={openInvoice}
          sx={rowClickSx}
        />
      )}

      <Typography variant="body2" data-testid="mocks-status">
        Mocks {areMocksEnabled() ? "enabled" : "disabled"} — {invoices.length} invoices
      </Typography>
    </Stack>
  );
}