import HistoryIcon from "@mui/icons-material/History";
import LockIcon from "@mui/icons-material/Lock";
import LockOpenIcon from "@mui/icons-material/LockOpen";
import PictureAsPdfIcon from "@mui/icons-material/PictureAsPdf";
import {
  Alert,
  Box,
  Button,
  Card,
  CardContent,
  CardHeader,
  Chip,
  CircularProgress,
  Divider,
  Grid,
  Stack,
  Tab,
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableRow,
  Tabs,
  Typography,
} from "@mui/material";
import { useState } from "react";
import { useParams } from "react-router-dom";
import { openBlob } from "../api/client";
import { useMe, useNcr, useNcrAudit } from "../api/hooks";
import type { NcrDetail } from "../api/types";
import { STAGE_LABELS } from "../api/types";
import { AttachmentSection } from "../components/AttachmentSection";
import { FieldRow } from "../components/FieldRow";
import { RichTextView } from "../components/RichTextView";
import { StageChip } from "../components/StageChip";
import { StageStepper } from "../components/StageStepper";
import { useToast } from "../components/Toast";
import { CapaSection } from "./CapaSection";
import {
  CostingForm,
  InitialDispositionForm,
  InspectionForm,
  OperationsForm,
  ReopenDialog,
  SecondaryDispositionForm,
} from "./StageForms";

function fmt(iso: string | null): string {
  return iso ? new Date(iso).toLocaleString() : "—";
}

function money(v: string | null): string {
  return v === null
    ? "—"
    : Number(v).toLocaleString(undefined, { style: "currency", currency: "USD" });
}

function SectionCard({
  title,
  action,
  children,
}: {
  title: string;
  action?: React.ReactNode;
  children: React.ReactNode;
}) {
  return (
    <Card sx={{ mb: 2 }}>
      <CardHeader title={title} action={action} titleTypographyProps={{ variant: "h6" }} />
      <Divider />
      <CardContent>{children}</CardContent>
    </Card>
  );
}

function AuditTab({ ncrId }: { ncrId: number }) {
  const audit = useNcrAudit(ncrId, true);
  if (audit.isLoading) return <CircularProgress sx={{ m: 2 }} />;
  if (audit.isError)
    return <Alert severity="error">{(audit.error as Error).message}</Alert>;
  const items = audit.data?.items ?? [];
  return (
    <Table size="small">
      <TableHead>
        <TableRow>
          <TableCell>When</TableCell>
          <TableCell>Who</TableCell>
          <TableCell>Action</TableCell>
          <TableCell>Field</TableCell>
          <TableCell>Before</TableCell>
          <TableCell>After</TableCell>
        </TableRow>
      </TableHead>
      <TableBody>
        {items.map((a) => (
          <TableRow key={a.id}>
            <TableCell sx={{ whiteSpace: "nowrap" }}>{fmt(a.created_at)}</TableCell>
            <TableCell>{a.user.display_name}</TableCell>
            <TableCell>
              <Chip size="small" label={a.action.replace(/_/g, " ")} />
              {a.detail && (
                <Typography variant="caption" display="block" color="text.secondary">
                  {a.detail}
                </Typography>
              )}
            </TableCell>
            <TableCell>{a.field_name ?? ""}</TableCell>
            <TableCell sx={{ maxWidth: 220, overflowWrap: "anywhere" }}>
              {a.old_value ?? ""}
            </TableCell>
            <TableCell sx={{ maxWidth: 220, overflowWrap: "anywhere" }}>
              {a.new_value ?? ""}
            </TableCell>
          </TableRow>
        ))}
      </TableBody>
    </Table>
  );
}

function DetailBody({ ncr }: { ncr: NcrDetail }) {
  const actions = ncr.available_actions;
  const closed = ncr.stage === "closed";

  return (
    <>
      {closed && (
        <Alert icon={<LockIcon />} severity="info" sx={{ mb: 2 }}>
          This NCR is closed and locked. Closed on {fmt(ncr.closed_at)} by{" "}
          {ncr.closed_by?.display_name}. Only an Admin can reopen it.
        </Alert>
      )}

      <SectionCard title="Request">
        <Grid container spacing={2}>
          <FieldRow label="Job Number">{ncr.job_number}</FieldRow>
          <FieldRow label="Date">{new Date(ncr.created_at).toLocaleDateString()}</FieldRow>
          <FieldRow label="Department">{ncr.department}</FieldRow>
          <FieldRow label="Deviation Category">{ncr.deviation_category}</FieldRow>
          <FieldRow label="Requester">{ncr.requester.display_name}</FieldRow>
          <FieldRow label="Disposition Authority">
            {ncr.disposition_authority.display_name}
          </FieldRow>
          {ncr.job_info && (
            <>
              <FieldRow label="Part (ERP)">
                {[ncr.job_info.part_id, ncr.job_info.part_description]
                  .filter(Boolean)
                  .join(" — ")}
              </FieldRow>
              <FieldRow label="Customer (ERP)">{ncr.job_info.customer_name}</FieldRow>
              <FieldRow label="WO Status (ERP)">{ncr.job_info.work_order_status}</FieldRow>
            </>
          )}
          <Grid item xs={12}>
            <Typography variant="caption" color="text.secondary" display="block">
              Deviation Detail
            </Typography>
            <Typography sx={{ whiteSpace: "pre-wrap" }}>{ncr.deviation_detail}</Typography>
          </Grid>
        </Grid>
        <Divider sx={{ my: 2 }} />
        <Typography variant="subtitle2" gutterBottom>
          Attachments
        </Typography>
        <AttachmentSection
          ncrId={ncr.id}
          attachments={ncr.attachments}
          canAdd={actions.includes("add_attachment")}
        />
      </SectionCard>

      <SectionCard title="Disposition">
        {ncr.stage === "new_request" && !actions.includes("initial_disposition") ? (
          <Typography color="text.secondary">
            Awaiting initial disposition by {ncr.disposition_authority.display_name}.
          </Typography>
        ) : (
          <Grid container spacing={2} sx={{ mb: 1 }}>
            <FieldRow label="QC Authority">{ncr.qc_authority}</FieldRow>
            <FieldRow label="Work Order">{ncr.work_order}</FieldRow>
            <FieldRow label="Secondary Review">
              {ncr.secondary_review_needed === null
                ? "—"
                : ncr.secondary_review_needed
                  ? `Yes — ${ncr.secondary_authorities.map((u) => u.display_name).join(", ") || "unassigned"}`
                  : "No"}
            </FieldRow>
            {ncr.disposition_notes && (
              <Grid item xs={12}>
                <Typography variant="caption" color="text.secondary" display="block">
                  Disposition Notes
                </Typography>
                <RichTextView html={ncr.disposition_notes} />
              </Grid>
            )}
          </Grid>
        )}
        {actions.includes("initial_disposition") && (
          <>
            <Divider sx={{ my: 2 }}>
              <Chip label="Initial Disposition — your action" color="primary" size="small" />
            </Divider>
            <InitialDispositionForm ncr={ncr} />
          </>
        )}
        {actions.includes("secondary_disposition") && (
          <>
            <Divider sx={{ my: 2 }}>
              <Chip label="Secondary Disposition — your action" color="primary" size="small" />
            </Divider>
            <SecondaryDispositionForm ncr={ncr} />
          </>
        )}
      </SectionCard>

      <SectionCard title="Operations">
        <Grid container spacing={2}>
          <FieldRow label="Operations Complete">
            {ncr.operations_complete ? "Yes" : "Pending"}
          </FieldRow>
          <FieldRow label="Completed By">
            {ncr.operations_completed_by?.display_name}
          </FieldRow>
          <FieldRow label="Completed At">{fmt(ncr.operations_completed_at)}</FieldRow>
        </Grid>
        {actions.includes("operations_complete") && (
          <>
            <Divider sx={{ my: 2 }}>
              <Chip label="Operations — your action" color="primary" size="small" />
            </Divider>
            <OperationsForm ncr={ncr} />
          </>
        )}
      </SectionCard>

      <SectionCard title="QC Inspection">
        <Grid container spacing={2}>
          <FieldRow label="QC Approval">
            {ncr.qc_approval === null ? "—" : ncr.qc_approval === "yes" ? "Yes" : "No"}
          </FieldRow>
          <FieldRow label="QC Closed">
            {ncr.qc_closed
              ? `Yes — ${ncr.qc_closed_by?.display_name}, ${fmt(ncr.qc_closed_at)}`
              : "Pending"}
          </FieldRow>
          {ncr.inspection_notes && (
            <Grid item xs={12}>
              <Typography variant="caption" color="text.secondary" display="block">
                Inspection Notes
              </Typography>
              <Typography sx={{ whiteSpace: "pre-wrap" }}>{ncr.inspection_notes}</Typography>
            </Grid>
          )}
        </Grid>
        {actions.includes("inspection") && (
          <>
            <Divider sx={{ my: 2 }}>
              <Chip label="QC Inspection — your action" color="primary" size="small" />
            </Divider>
            <InspectionForm ncr={ncr} />
          </>
        )}
      </SectionCard>

      <SectionCard title="Corrective & Preventive Action (API Q1)">
        <CapaSection ncr={ncr} />
      </SectionCard>

      <SectionCard title="Costing">
        <Grid container spacing={2}>
          <FieldRow label="Labor">{money(ncr.labor_cost)}</FieldRow>
          <FieldRow label="Material">{money(ncr.material_cost)}</FieldRow>
          <FieldRow label="Service">{money(ncr.service_cost)}</FieldRow>
          <FieldRow label="Other">{money(ncr.other_cost)}</FieldRow>
          <FieldRow label="Total">
            <Typography component="span" fontWeight={700}>
              {money(ncr.total_cost)}
            </Typography>
          </FieldRow>
          <FieldRow label="Costed By">
            {ncr.costing_completed_by
              ? `${ncr.costing_completed_by.display_name}, ${fmt(ncr.costing_completed_at)}`
              : null}
          </FieldRow>
        </Grid>
        {actions.includes("costing") && (
          <>
            <Divider sx={{ my: 2 }}>
              <Chip label="Costing — your action" color="primary" size="small" />
            </Divider>
            <CostingForm ncr={ncr} />
          </>
        )}
      </SectionCard>

      <SectionCard title="Workflow History">
        <Table size="small">
          <TableHead>
            <TableRow>
              <TableCell>When</TableCell>
              <TableCell>Action</TableCell>
              <TableCell>From</TableCell>
              <TableCell>To</TableCell>
              <TableCell>By</TableCell>
            </TableRow>
          </TableHead>
          <TableBody>
            {ncr.transitions.map((t) => (
              <TableRow key={t.id}>
                <TableCell sx={{ whiteSpace: "nowrap" }}>{fmt(t.acted_at)}</TableCell>
                <TableCell>
                  {t.action.replace(/_/g, " ")}
                  {t.note && (
                    <Typography variant="caption" display="block" color="text.secondary">
                      {t.note}
                    </Typography>
                  )}
                </TableCell>
                <TableCell>{t.from_stage ? STAGE_LABELS[t.from_stage] : "—"}</TableCell>
                <TableCell>{STAGE_LABELS[t.to_stage]}</TableCell>
                <TableCell>{t.acted_by.display_name}</TableCell>
              </TableRow>
            ))}
          </TableBody>
        </Table>
      </SectionCard>
    </>
  );
}

export function NcrDetailPage() {
  // URL carries the NCR business number (e.g. /ncrs/NCR-2026-0021); numeric
  // ids from older links still resolve server-side.
  const { id } = useParams();
  const ncrQuery = useNcr(id);
  const me = useMe();
  const { toast } = useToast();
  const [tab, setTab] = useState(0);
  const [reopenOpen, setReopenOpen] = useState(false);

  if (ncrQuery.isLoading) {
    return (
      <Box sx={{ textAlign: "center", py: 8 }}>
        <CircularProgress />
      </Box>
    );
  }
  if (ncrQuery.isError || !ncrQuery.data) {
    return (
      <Alert severity="error">
        {(ncrQuery.error as Error | undefined)?.message ?? "NCR not found."}
      </Alert>
    );
  }
  const ncr = ncrQuery.data;
  const canAudit =
    ncr.available_actions.includes("view_audit") ||
    (me.data?.roles.includes("admin") ?? false);

  return (
    <Box sx={{ maxWidth: 1100, mx: "auto" }}>
      <Stack
        direction={{ xs: "column", md: "row" }}
        justifyContent="space-between"
        alignItems={{ md: "center" }}
        spacing={1}
        sx={{ mb: 1 }}
      >
        <Stack direction="row" spacing={1.5} alignItems="center">
          <Typography variant="h5">{ncr.ncr_number}</Typography>
          <StageChip stage={ncr.stage} size="medium" />
          <Typography color="text.secondary" variant="body2">
            {ncr.days_in_stage}d in stage
          </Typography>
        </Stack>
        <Stack direction="row" spacing={1}>
          <Button
            startIcon={<PictureAsPdfIcon />}
            variant="outlined"
            onClick={() =>
              void openBlob(`/api/ncrs/${ncr.id}/pdf`, `${ncr.ncr_number}.pdf`, "open").catch(
                (e) => toast(e.message, "error"),
              )
            }
          >
            Print / Download PDF
          </Button>
          {ncr.available_actions.includes("reopen") && (
            <Button
              startIcon={<LockOpenIcon />}
              variant="outlined"
              color="warning"
              onClick={() => setReopenOpen(true)}
            >
              Reopen
            </Button>
          )}
        </Stack>
      </Stack>

      <StageStepper ncr={ncr} />

      {canAudit ? (
        <>
          <Tabs value={tab} onChange={(_, v) => setTab(v)} sx={{ mb: 2 }}>
            <Tab label="Details" />
            <Tab icon={<HistoryIcon />} iconPosition="start" label="Audit History" />
          </Tabs>
          {tab === 0 ? (
            <DetailBody ncr={ncr} />
          ) : (
            <Card>
              <CardContent>
                <AuditTab ncrId={ncr.id} />
              </CardContent>
            </Card>
          )}
        </>
      ) : (
        <DetailBody ncr={ncr} />
      )}

      <ReopenDialog ncr={ncr} open={reopenOpen} onClose={() => setReopenOpen(false)} />
    </Box>
  );
}