import { useMemo } from 'react';
import { useParams } from 'react-router';
import {
  KpiStrip,
  DataTable,
  AreaChart,
  LineChart,
  Card,
  MonoText,
  Badge,
} from '@cameleer/design-system';
import type { KpiItem, Column } from '@cameleer/design-system';
import { useGlobalFilters } from '@cameleer/design-system';
import { useExecutionStats, useStatsTimeseries } from '../../api/queries/executions';
import { useProcessorMetrics } from '../../api/queries/processor-metrics';
import { useTopErrors, useAppSettings } from '../../api/queries/dashboard';
import type { TopError } from '../../api/queries/dashboard';
import { useDiagramByRoute } from '../../api/queries/diagrams';
import { ProcessDiagram } from '../../components/ProcessDiagram';
import {
  formatRelativeTime,
  trendArrow,
  formatThroughput,
  formatSlaCompliance,
  trendIndicator,
} from './dashboard-utils';
import styles from './DashboardTab.module.css';

// ── Row types ───────────────────────────────────────────────────────────────

interface ProcessorRow {
  id: string;
  processorId: string;
  processorType: string;
  totalCount: number;
  avgDurationMs: number;
  p99DurationMs: number;
  errorRate: number;
  pctTime: number;
}

interface ErrorRow extends TopError {
  id: string;
}

// ── Processor table columns ─────────────────────────────────────────────────

const PROCESSOR_COLUMNS: Column<ProcessorRow>[] = [
  {
    key: 'processorId',
    header: 'Processor ID',
    sortable: true,
    render: (_, row) => <MonoText size="sm">{row.processorId}</MonoText>,
  },
  {
    key: 'processorType',
    header: 'Type',
    sortable: true,
    render: (_, row) => <Badge label={row.processorType} color="auto" />,
  },
  {
    key: 'totalCount',
    header: 'Invocations',
    sortable: true,
    render: (_, row) => (
      <MonoText size="sm">{row.totalCount.toLocaleString()}</MonoText>
    ),
  },
  {
    key: 'avgDurationMs',
    header: 'Avg(ms)',
    sortable: true,
    render: (_, row) => (
      <MonoText size="sm">{Math.round(row.avgDurationMs)}</MonoText>
    ),
  },
  {
    key: 'p99DurationMs',
    header: 'P99(ms)',
    sortable: true,
    render: (_, row) => {
      const cls = row.p99DurationMs > 300
        ? styles.rateBad
        : row.p99DurationMs > 200
          ? styles.rateWarn
          : styles.rateGood;
      return <MonoText size="sm" className={cls}>{Math.round(row.p99DurationMs)}</MonoText>;
    },
  },
  {
    key: 'errorRate',
    header: 'Error Rate(%)',
    sortable: true,
    render: (_, row) => {
      const pct = row.errorRate * 100;
      const cls = pct > 5 ? styles.rateBad : pct > 1 ? styles.rateWarn : styles.rateGood;
      return <MonoText size="sm" className={cls}>{pct.toFixed(2)}%</MonoText>;
    },
  },
  {
    key: 'pctTime',
    header: '% Time',
    sortable: true,
    render: (_, row) => (
      <MonoText size="sm">{row.pctTime.toFixed(1)}%</MonoText>
    ),
  },
];

// ── Error table columns ─────────────────────────────────────────────────────

const ERROR_COLUMNS: Column<ErrorRow>[] = [
  {
    key: 'errorType',
    header: 'Error Type',
    sortable: true,
    render: (_, row) => <MonoText size="sm">{row.errorType}</MonoText>,
  },
  {
    key: 'processorId',
    header: 'Processor',
    sortable: true,
    render: (_, row) => (
      <MonoText size="sm">{row.processorId ?? '\u2014'}</MonoText>
    ),
  },
  {
    key: 'count',
    header: 'Count',
    sortable: true,
    render: (_, row) => (
      <MonoText size="sm">{row.count.toLocaleString()}</MonoText>
    ),
  },
  {
    key: 'trend',
    header: 'Velocity',
    render: (_, row) => (
      <span>{trendArrow(row.trend)} {row.trend}</span>
    ),
  },
  {
    key: 'lastSeen',
    header: 'Last Seen',
    sortable: true,
    render: (_, row) => (
      <span>{formatRelativeTime(row.lastSeen)}</span>
    ),
  },
];

// ── Build KPI items ─────────────────────────────────────────────────────────

function buildKpiItems(
  stats: {
    totalCount: number;
    failedCount: number;
    avgDurationMs: number;
    p99LatencyMs: number;
    activeCount: number;
    prevTotalCount: number;
    prevFailedCount: number;
    prevP99LatencyMs: number;
  } | undefined,
  slaThresholdMs: number,
  bottleneck: { processorId: string; avgMs: number; pct: number } | null,
  throughputSparkline: number[],
  windowSeconds: number,
): KpiItem[] {
  const totalCount = stats?.totalCount ?? 0;
  const failedCount = stats?.failedCount ?? 0;
  const prevTotalCount = stats?.prevTotalCount ?? 0;
  const p99Ms = stats?.p99LatencyMs ?? 0;
  const avgMs = stats?.avgDurationMs ?? 0;

  const successRate = totalCount > 0 ? ((totalCount - failedCount) / totalCount) * 100 : 100;
  const slaCompliance = totalCount > 0
    ? ((totalCount - failedCount) / totalCount) * 100
    : 100;

  const throughputTrend = trendIndicator(totalCount, prevTotalCount);

  return [
    {
      label: 'Throughput',
      value: formatThroughput(totalCount, windowSeconds),
      trend: {
        label: throughputTrend.label,
        variant: throughputTrend.direction === 'up' ? 'success' as const : throughputTrend.direction === 'down' ? 'error' as const : 'muted' as const,
      },
      subtitle: `${totalCount.toLocaleString()} total exchanges`,
      sparkline: throughputSparkline,
      borderColor: 'var(--amber)',
    },
    {
      label: 'Success Rate',
      value: `${successRate.toFixed(2)}%`,
      trend: {
        label: failedCount > 0 ? `${failedCount} failed` : 'No errors',
        variant: successRate >= 99 ? 'success' as const : successRate >= 97 ? 'warning' as const : 'error' as const,
      },
      subtitle: `${totalCount - failedCount} succeeded / ${totalCount.toLocaleString()} total`,
      borderColor: successRate >= 99 ? 'var(--success)' : 'var(--error)',
    },
    {
      label: 'P99 Latency',
      value: `${Math.round(p99Ms)}ms`,
      trend: {
        label: p99Ms > slaThresholdMs ? 'BREACH' : 'OK',
        variant: p99Ms > slaThresholdMs ? 'error' as const : 'success' as const,
      },
      subtitle: `SLA threshold: ${slaThresholdMs}ms \u00B7 Avg: ${Math.round(avgMs)}ms`,
      borderColor: p99Ms > slaThresholdMs ? 'var(--warning)' : 'var(--success)',
    },
    {
      label: 'SLA Compliance',
      value: formatSlaCompliance(slaCompliance),
      trend: {
        label: slaCompliance >= 99.9 ? 'Excellent' : slaCompliance >= 99 ? 'Good' : 'Degraded',
        variant: slaCompliance >= 99 ? 'success' as const : slaCompliance >= 95 ? 'warning' as const : 'error' as const,
      },
      subtitle: `Target: 99.9%`,
      borderColor: slaCompliance >= 99 ? 'var(--success)' : 'var(--warning)',
    },
    {
      label: 'Bottleneck',
      value: bottleneck ? `${Math.round(bottleneck.avgMs)}ms` : '\u2014',
      trend: {
        label: bottleneck ? `${bottleneck.pct.toFixed(1)}% of total` : '\u2014',
        variant: bottleneck && bottleneck.pct > 50 ? 'error' as const : 'muted' as const,
      },
      subtitle: bottleneck
        ? `${bottleneck.processorId} \u00B7 ${Math.round(bottleneck.avgMs)}ms \u00B7 ${bottleneck.pct.toFixed(1)}% of total`
        : 'No processor data',
      borderColor: 'var(--running)',
    },
  ];
}

// ── Component ───────────────────────────────────────────────────────────────

export default function DashboardL3() {
  const { appId, routeId } = useParams<{ appId: string; routeId: string }>();
  const { timeRange } = useGlobalFilters();
  const timeFrom = timeRange.start.toISOString();
  const timeTo = timeRange.end.toISOString();
  const windowSeconds = (timeRange.end.getTime() - timeRange.start.getTime()) / 1000;

  // ── Data hooks ──────────────────────────────────────────────────────────
  const { data: stats } = useExecutionStats(timeFrom, timeTo, routeId, appId);
  const { data: timeseries } = useStatsTimeseries(timeFrom, timeTo, routeId, appId);
  const { data: processorMetrics } = useProcessorMetrics(routeId ?? null, appId);
  const { data: topErrors } = useTopErrors(timeFrom, timeTo, appId, routeId);
  const { data: diagramLayout } = useDiagramByRoute(appId, routeId);
  const { data: appSettings } = useAppSettings(appId);

  const slaThresholdMs = appSettings?.slaThresholdMs ?? 300;

  // ── Bottleneck (processor with highest avgDurationMs) ───────────────────
  const bottleneck = useMemo(() => {
    if (!processorMetrics?.length) return null;
    const routeAvg = stats?.avgDurationMs ?? 0;
    const sorted = [...processorMetrics].sort(
      (a: any, b: any) => b.avgDurationMs - a.avgDurationMs,
    );
    const top = sorted[0];
    const pct = routeAvg > 0 ? (top.avgDurationMs / routeAvg) * 100 : 0;
    return { processorId: top.processorId, avgMs: top.avgDurationMs, pct };
  }, [processorMetrics, stats]);

  // ── Sparklines from timeseries ──────────────────────────────────────────
  const throughputSparkline = useMemo(
    () => (timeseries?.buckets || []).map((b: any) => b.totalCount),
    [timeseries],
  );

  // ── KPI strip ───────────────────────────────────────────────────────────
  const kpiItems = useMemo(
    () => buildKpiItems(stats, slaThresholdMs, bottleneck, throughputSparkline, windowSeconds),
    [stats, slaThresholdMs, bottleneck, throughputSparkline, windowSeconds],
  );

  // ── Chart series ────────────────────────────────────────────────────────
  const throughputChartSeries = useMemo(() => [{
    label: 'Throughput',
    data: (timeseries?.buckets || []).map((b: any, i: number) => ({
      x: i,
      y: b.totalCount,
    })),
  }], [timeseries]);

  const latencyChartSeries = useMemo(() => [{
    label: 'P99',
    data: (timeseries?.buckets || []).map((b: any, i: number) => ({
      x: i,
      y: b.p99DurationMs,
    })),
  }], [timeseries]);

  const errorRateChartSeries = useMemo(() => [{
    label: 'Error Rate',
    data: (timeseries?.buckets || []).map((b: any, i: number) => ({
      x: i,
      y: b.totalCount > 0 ? (b.failedCount / b.totalCount) * 100 : 0,
    })),
    color: 'var(--error)',
  }], [timeseries]);

  // ── Processor table rows ────────────────────────────────────────────────
  const processorRows: ProcessorRow[] = useMemo(() => {
    if (!processorMetrics?.length) return [];
    const routeAvg = stats?.avgDurationMs ?? 0;
    return processorMetrics.map((m: any) => ({
      id: m.processorId,
      processorId: m.processorId,
      processorType: m.processorType,
      totalCount: m.totalCount,
      avgDurationMs: m.avgDurationMs,
      p99DurationMs: m.p99DurationMs,
      errorRate: m.errorRate,
      pctTime: routeAvg > 0 ? (m.avgDurationMs / routeAvg) * 100 : 0,
    }));
  }, [processorMetrics, stats]);

  // ── Latency heatmap for ProcessDiagram ──────────────────────────────────
  const latencyHeatmap = useMemo(() => {
    if (!processorMetrics?.length) return new Map();
    const totalAvg = processorMetrics.reduce(
      (sum: number, m: any) => sum + m.avgDurationMs, 0,
    );
    const map = new Map<string, { avgDurationMs: number; p99DurationMs: number; pctOfRoute: number }>();
    for (const m of processorMetrics) {
      map.set(m.processorId, {
        avgDurationMs: m.avgDurationMs,
        p99DurationMs: m.p99DurationMs,
        pctOfRoute: totalAvg > 0 ? (m.avgDurationMs / totalAvg) * 100 : 0,
      });
    }
    return map;
  }, [processorMetrics]);

  // ── Error table rows ────────────────────────────────────────────────────
  const errorRows: ErrorRow[] = useMemo(
    () => (topErrors || []).map((e, i) => ({ ...e, id: `${e.errorType}-${i}` })),
    [topErrors],
  );

  return (
    <div className={styles.content}>
      <div className={styles.refreshIndicator}>
        <span className={styles.refreshDot} />
        <span className={styles.refreshText}>Auto-refresh: 30s</span>
      </div>

      {/* KPI Strip */}
      <KpiStrip items={kpiItems} />

      {/* Charts — 3 in a row */}
      {(timeseries?.buckets?.length ?? 0) > 0 && (
        <div className={styles.chartRow}>
          <Card title="Throughput">
            <AreaChart
              series={throughputChartSeries}
              yLabel="msg/s"
              height={200}
            />
          </Card>

          <Card title="Latency Percentiles">
            <LineChart
              series={latencyChartSeries}
              yLabel="ms"
              threshold={{ value: slaThresholdMs, label: `SLA ${slaThresholdMs}ms` }}
              height={200}
            />
          </Card>

          <Card title="Error Rate">
            <AreaChart
              series={errorRateChartSeries}
              yLabel="%"
              height={200}
            />
          </Card>
        </div>
      )}

      {/* Process Diagram with Latency Heatmap */}
      {appId && routeId && (
        <div className={styles.diagramSection}>
          <ProcessDiagram
            application={appId}
            routeId={routeId}
            diagramLayout={diagramLayout}
            latencyHeatmap={latencyHeatmap}
          />
        </div>
      )}

      {/* Processor Metrics Table */}
      <div className={styles.tableSection}>
        <div className={styles.tableHeader}>
          <span className={styles.tableTitle}>Processor Metrics</span>
          <div>
            <span className={styles.tableMeta}>
              {processorRows.length} processor{processorRows.length !== 1 ? 's' : ''}
            </span>
          </div>
        </div>
        <DataTable
          columns={PROCESSOR_COLUMNS}
          data={processorRows}
          sortable
        />
      </div>

      {/* Top 5 Errors — hidden if empty */}
      {errorRows.length > 0 && (
        <div className={styles.errorsSection}>
          <div className={styles.tableHeader}>
            <span className={styles.tableTitle}>Top 5 Errors</span>
            <Badge label={`${errorRows.length}`} color="error" />
          </div>
          <DataTable
            columns={ERROR_COLUMNS}
            data={errorRows}
            sortable
          />
        </div>
      )}
    </div>
  );
}