import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query"
import { createFileRoute, Link } from "@tanstack/react-router"
import { AlertCircle, Workflow } from "lucide-react"
import { useState } from "react"

import { type FlowSummary, FlowsService } from "@/client"
import { DEFAULT_RANGE } from "@/components/Common/RangePicker"
import { BrainView } from "@/components/Flow/BrainView"
import { flowKeys, flowsQueryOptions } from "@/components/Flow/queries"
import { HealthActivity } from "@/components/Health/HealthActivity"
import { HealthOverview } from "@/components/Health/HealthOverview"
import { Badge } from "@/components/ui/badge"
import { Card } from "@/components/ui/card"
import { Skeleton } from "@/components/ui/skeleton"
import { Switch } from "@/components/ui/switch"
import useCustomToast from "@/hooks/useCustomToast"

export const Route = createFileRoute("/_layout/")({
  component: Dashboard,
  head: () => ({
    meta: [
      {
        title: "Dashboard - Fluksio",
      },
    ],
  }),
})

/** Another tab can stop a flow, and the engine can fail one on its own. */
const REFRESH_INTERVAL = 10_000

function FlowRow({ flow }: { flow: FlowSummary }) {
  const queryClient = useQueryClient()
  const { showErrorToast } = useCustomToast()
  const enabled = flow.enabled ?? true

  const toggle = useMutation({
    mutationFn: (next: boolean) =>
      next
        ? FlowsService.startFlow({ name: flow.name })
        : FlowsService.stopFlow({ name: flow.name }),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: flowKeys.all })
      queryClient.invalidateQueries({ queryKey: flowKeys.detail(flow.name) })
    },
    onError: () => showErrorToast("The flow could not be started or stopped."),
  })

  return (
    <div
      className="flex items-center gap-3 border-b border-border px-5 py-3 last:border-b-0"
      data-testid="dashboard-flow-row"
    >
      <Link
        to="/flows/$flowName"
        params={{ flowName: flow.name }}
        className="min-w-0 flex-1"
      >
        <p className="truncate font-medium">{flow.title || flow.name}</p>
        <p className="truncate text-sm text-muted-foreground">
          {flow.node_count === 1 ? "1 node" : `${flow.node_count} nodes`}
          {flow.has_draft ? " · unpublished changes" : ""}
        </p>
      </Link>

      {(flow.error_count ?? 0) > 0 ? (
        <Badge variant="destructive" className="gap-1">
          <AlertCircle />
          {flow.error_count}
        </Badge>
      ) : null}

      <Badge
        variant="outline"
        className={
          enabled
            ? flow.paused
              ? "border-transparent bg-primary/15 text-primary"
              : "border-transparent bg-status-success/15 text-status-success"
            : "text-muted-foreground"
        }
      >
        {enabled ? (flow.paused ? "Paused" : "Running") : "Stopped"}
      </Badge>

      <Switch
        checked={enabled}
        disabled={toggle.isPending}
        onCheckedChange={(next) => toggle.mutate(next)}
        aria-label={`Run ${flow.title || flow.name}`}
        data-testid="flow-enabled-switch"
      />
    </div>
  )
}

/**
 * The one overview: what the engine is wired up as, what is running, and how
 * it has been doing. The brain and the health screens compose in here rather
 * than living at routes of their own.
 */
function Dashboard() {
  // The health block's window: one choice, read by the tiles, the flow table,
  // the charts and the lists under them.
  const [range, setRange] = useState(DEFAULT_RANGE)
  const { data, isPending } = useQuery({
    ...flowsQueryOptions(),
    refetchInterval: REFRESH_INTERVAL,
  })

  const flows = data?.data ?? []

  return (
    // `[&>*]:min-w-0`: a grid item's automatic minimum is its content, so one
    // long name or wide table widens the whole column and the page with it.
    // Every section here is free to shrink instead. See DESIGN-GUIDELINES.md
    // → Responsive.
    <div className="grid gap-6 [&>*]:min-w-0">
      <BrainView />

      <Card className="gap-0 py-0">
        {isPending ? (
          <div className="grid gap-3 p-5">
            <Skeleton className="h-5 w-40" />
            <Skeleton className="h-5 w-28" />
          </div>
        ) : flows.length === 0 ? (
          <div className="flex flex-col items-center gap-3 px-5 py-10 text-center">
            <span className="flex size-12 items-center justify-center rounded-full bg-muted text-muted-foreground">
              <Workflow className="size-5" />
            </span>
            <p className="text-sm text-muted-foreground">
              Flows you build show up here, with what they are doing.
            </p>
            <Link to="/flows" className="text-sm font-medium underline">
              Go to flows
            </Link>
          </div>
        ) : (
          flows.map((flow) => <FlowRow key={flow.name} flow={flow} />)
        )}
      </Card>

      <HealthOverview range={range} onRangeChange={setRange} />
      <HealthActivity range={range} />
    </div>
  )
}