import { useState } from "react";
import { useNavigate } from "react-router-dom";
import { useQuery } from "@tanstack/react-query";
import { LayoutTemplate, Cpu, Package } from "lucide-react";
import { Badge, Button, Card, Input, Spinner } from "@/components/ui";
import { templatesApi, type TemplateDetail, type TemplateSummary } from "@/api/templates";
import { agentsApi } from "@/api/agents";
import { apiErrorMessage } from "@/api/client";
import { useAuthStore } from "@/store/auth";
import { toast } from "sonner";

const selectClass =
  "w-full rounded-lg border border-slate-300 bg-white px-3 py-2 text-sm dark:border-slate-600 dark:bg-slate-800";

export function Templates() {
  const isAdmin = useAuthStore((s) => s.user?.role === "admin");
  const [selected, setSelected] = useState<TemplateDetail | null>(null);
  const { data, isLoading } = useQuery({ queryKey: ["templates"], queryFn: templatesApi.list });

  const open = async (t: TemplateSummary) => {
    try {
      setSelected(await templatesApi.get(t.id));
    } catch (e) {
      toast.error(apiErrorMessage(e));
    }
  };

  if (isLoading) return <Spinner />;

  return (
    <div className="space-y-4">
      <div className="grid grid-cols-1 gap-4 md:grid-cols-2 xl:grid-cols-3">
        {data?.map((t) => (
          <Card key={t.id} className="flex flex-col gap-2">
            <div className="flex items-center gap-2">
              {t.source === "custom" ? (
                <Package className="h-5 w-5 text-accent dark:text-accent-dark" />
              ) : (
                <LayoutTemplate className="h-5 w-5 text-accent dark:text-accent-dark" />
              )}
              <span className="font-semibold">{t.name}</span>
              {t.source === "custom" && <Badge>custom</Badge>}
            </div>
            {t.description && <p className="text-sm text-slate-500">{t.description}</p>}
            <div className="flex flex-wrap gap-1">
              {t.tags.map((tag) => (
                <span key={tag} className="rounded-full bg-slate-100 px-2 py-0.5 text-xs text-slate-600 dark:bg-slate-700 dark:text-slate-300">
                  {tag}
                </span>
              ))}
              {t.gpu && (
                <span className="inline-flex items-center gap-1 rounded-full bg-emerald-100 px-2 py-0.5 text-xs text-emerald-700 dark:bg-emerald-900/40 dark:text-emerald-300">
                  <Cpu className="h-3 w-3" /> {t.gpu}
                </span>
              )}
            </div>
            {isAdmin && (
              <Button variant="outline" className="mt-2" onClick={() => open(t)}>
                Use template
              </Button>
            )}
          </Card>
        ))}
      </div>

      {selected && (
        <UseTemplateDialog template={selected} onClose={() => setSelected(null)} />
      )}
    </div>
  );
}

function UseTemplateDialog({
  template,
  onClose,
}: {
  template: TemplateDetail;
  onClose: () => void;
}) {
  const navigate = useNavigate();
  const [name, setName] = useState(template.name);
  const [values, setValues] = useState<Record<string, string>>(
    Object.fromEntries(template.variables.map((v) => [v.name, v.default]))
  );
  const [host, setHost] = useState("local");
  const [busy, setBusy] = useState(false);

  const agents = useQuery({ queryKey: ["agents"], queryFn: () => agentsApi.list() });
  const onlineAgents = (agents.data ?? []).filter((a) => a.status === "online");

  const create = async () => {
    if (!name.trim()) {
      toast.error("Stack name required");
      return;
    }
    setBusy(true);
    try {
      const agentId = host === "local" ? null : Number(host);
      const res = await templatesApi.instantiate(template.id, name, values, agentId);
      toast.success(`Stack '${res.name}' created`);
      if (res.agent_id != null) navigate(`/hosts/${res.agent_id}/stacks/${res.id}`);
      else navigate(`/stacks/${res.id}/edit`);
    } catch (e) {
      toast.error(apiErrorMessage(e));
    } finally {
      setBusy(false);
    }
  };

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 p-4">
      <div className="max-h-[85vh] w-full max-w-lg overflow-auto rounded-xl border border-slate-200 bg-card p-5 shadow-xl dark:border-slate-700 dark:bg-card-dark">
        <h2 className="mb-3 text-lg font-semibold">Use “{template.name}”</h2>
        <div className="space-y-3">
          <label className="block space-y-1">
            <span className="text-xs font-medium text-slate-500">Stack name</span>
            <Input value={name} onChange={(e) => setName(e.target.value)} />
          </label>
          {onlineAgents.length > 0 && (
            <label className="block space-y-1">
              <span className="text-xs font-medium text-slate-500">Deploy to host</span>
              <select className={selectClass} value={host} onChange={(e) => setHost(e.target.value)}>
                <option value="local">This host</option>
                {onlineAgents.map((a) => (
                  <option key={a.id} value={String(a.id)}>
                    {a.name}
                  </option>
                ))}
              </select>
            </label>
          )}
          {template.variables.map((v) => (
            <label key={v.name} className="block space-y-1">
              <span className="text-xs font-medium text-slate-500">
                {v.name}
                {v.description && <span className="ml-1 font-normal text-slate-400">— {v.description}</span>}
              </span>
              <Input
                value={values[v.name] ?? ""}
                onChange={(e) => setValues((s) => ({ ...s, [v.name]: e.target.value }))}
              />
            </label>
          ))}
        </div>
        <div className="mt-4 flex justify-end gap-2">
          <Button variant="outline" onClick={onClose}>Cancel</Button>
          <Button onClick={create} loading={busy}>Create stack</Button>
        </div>
      </div>
    </div>
  );
}