import { useMemo, useState } from "react";
import { Link, useSearchParams } from "react-router-dom";
import { useQuery } from "@tanstack/react-query";
import { Plus, Search, HardDrive } from "lucide-react";
import { Button, Input } from "@/components/ui";
import { StacksTable } from "@/components/stacks/StacksTable";
import { RestoreButton } from "@/components/stacks/BackupRestore";
import { AgentStacksSection } from "@/components/stacks/AgentStacksSection";
import { stacksApi } from "@/api/stacks";
import { systemApi } from "@/api/system";
import { agentsApi } from "@/api/agents";
import { useAuthStore } from "@/store/auth";
import { useStackActions } from "@/hooks/useStackActions";

type SortKey = "name" | "status" | "updated";
type StatusFilter = "all" | "running" | "stopped" | "attention";

const STATUS_FILTERS: Record<string, StatusFilter> = {
  running: "running",
  stopped: "stopped",
  attention: "attention",
};

export function Stacks() {
  const isAdmin = useAuthStore((s) => s.user?.role === "admin");
  const { busyId, start, stop, restart, updateImages } = useStackActions();
  // The dashboard explore bar deep-links here with ?q= / ?filter=.
  const [params] = useSearchParams();
  const [q, setQ] = useState(params.get("q") ?? "");
  const [statusFilter, setStatusFilter] = useState<StatusFilter>(
    STATUS_FILTERS[params.get("filter") ?? ""] ?? "all"
  );
  const [sort, setSort] = useState<SortKey>("name");

  const { data, isLoading } = useQuery({
    queryKey: ["stacks"],
    queryFn: stacksApi.list,
    refetchInterval: 5000,
  });

  const stats = useQuery({
    queryKey: ["stack-stats"],
    queryFn: stacksApi.stats,
    refetchInterval: 5000,
  });
  const updates = useQuery({
    queryKey: ["stack-updates"],
    queryFn: stacksApi.updates,
    refetchInterval: 60000,
  });
  const info = useQuery({
    queryKey: ["system"],
    queryFn: systemApi.info,
    refetchInterval: 5000,
  });

  const agents = useQuery({
    queryKey: ["agents"],
    queryFn: () => agentsApi.list(),
    refetchInterval: 15000,
  });
  const hasAgents = (agents.data?.length ?? 0) > 0;

  const filtered = useMemo(() => {
    let list = (data ?? []).filter(
      (s) =>
        s.name.toLowerCase().includes(q.toLowerCase()) ||
        s.id.toLowerCase().includes(q.toLowerCase())
    );
    if (statusFilter !== "all") {
      list = list.filter((s) =>
        statusFilter === "attention"
          ? s.status === "error" || s.status === "partial"
          : s.status === statusFilter
      );
    }
    list = [...list].sort((a, b) => {
      if (sort === "name") return a.name.localeCompare(b.name);
      if (sort === "status") return a.status.localeCompare(b.status);
      return b.updated_at.localeCompare(a.updated_at);
    });
    return list;
  }, [data, q, statusFilter, sort]);

  return (
    <div className="space-y-4">
      <div className="flex flex-wrap items-center gap-3">
        <div className="relative flex-1 min-w-[200px]">
          <Search className="absolute left-3 top-2.5 h-4 w-4 text-slate-400" />
          <Input
            className="pl-9"
            placeholder="Search stacks…"
            value={q}
            onChange={(e) => setQ(e.target.value)}
          />
        </div>
        <select
          value={statusFilter}
          onChange={(e) => setStatusFilter(e.target.value as StatusFilter)}
          className="rounded-lg border border-slate-300 bg-white px-3 py-2 text-sm dark:border-slate-600 dark:bg-slate-800"
        >
          <option value="all">All statuses</option>
          <option value="running">Running</option>
          <option value="stopped">Stopped</option>
          <option value="attention">Needs attention</option>
        </select>
        <select
          value={sort}
          onChange={(e) => setSort(e.target.value as SortKey)}
          className="rounded-lg border border-slate-300 bg-white px-3 py-2 text-sm dark:border-slate-600 dark:bg-slate-800"
        >
          <option value="name">Sort: Name</option>
          <option value="status">Sort: Status</option>
          <option value="updated">Sort: Last updated</option>
        </select>
        {isAdmin && <RestoreButton />}
        {isAdmin && (
          <Link to="/stacks/new">
            <Button>
              <Plus className="h-4 w-4" /> New Stack
            </Button>
          </Link>
        )}
      </div>

      <section>
        {hasAgents && (
          <h2 className="mb-3 flex items-center gap-2 text-sm font-semibold uppercase tracking-wide text-slate-500">
            <HardDrive className="h-4 w-4" /> This host
          </h2>
        )}
        <StacksTable
          stacks={filtered}
          stats={stats.data}
          updates={updates.data}
          hostCpus={info.data?.cpu_cores ?? 0}
          hostMem={info.data?.ram.total ?? 0}
          isAdmin={isAdmin}
          busyId={busyId}
          loading={isLoading}
          showEdit
          showDelete
          onStart={start}
          onStop={stop}
          onRestart={restart}
          onUpdate={isAdmin ? updateImages : undefined}
          emptyText={q ? "No stacks match your search." : "No stacks yet. Create one with “New Stack”."}
        />
      </section>

      {agents.data?.map((agent) => (
        <AgentStacksSection key={agent.id} agent={agent} isAdmin={isAdmin} />
      ))}
    </div>
  );
}