import { useEffect, useState } from "react";
import { useNavigate, useParams } from "react-router-dom";
import { useQuery, useQueryClient } from "@tanstack/react-query";
import Editor from "@monaco-editor/react";
import { Rocket, Save, Wand2, FileCode } from "lucide-react";
import { Button, Card, Input } from "@/components/ui";
import { EditorHelperPanel } from "@/components/stacks/EditorHelperPanel";
import { EnvEditor } from "@/components/env/EnvEditor";
import { PortConflictDialog } from "@/components/stacks/PortConflictDialog";
import { DeployConsole } from "@/components/stacks/DeployConsole";
import { stacksApi } from "@/api/stacks";
import { agentsApi } from "@/api/agents";
import { portsApi, type PortConflict } from "@/api/ports";
import { apiErrorMessage } from "@/api/client";
import { useThemeStore } from "@/store/theme";
import { toast } from "sonner";

const STARTER = `services:
  app:
    image: nginx:alpine
    restart: unless-stopped
    ports:
      - "8080:80"
`;

export function StackEditor() {
  const { id } = useParams();
  const isNew = !id;
  const navigate = useNavigate();
  const qc = useQueryClient();
  const theme = useThemeStore((s) => s.theme);

  const [name, setName] = useState("");
  const [description, setDescription] = useState("");
  const [yaml, setYaml] = useState(STARTER);
  const [env, setEnv] = useState("");
  const [tab, setTab] = useState<"compose" | "env">("compose");
  const [saving, setSaving] = useState(false);
  const [convertOpen, setConvertOpen] = useState(false);
  const [runCmd, setRunCmd] = useState("");
  const [conflicts, setConflicts] = useState<PortConflict[] | null>(null);
  const [checking, setChecking] = useState(false);
  const [host, setHost] = useState("local");
  const [deployId, setDeployId] = useState<string | null>(null);
  const [deployAgentId, setDeployAgentId] = useState<number | undefined>(undefined);

  const existing = useQuery({
    queryKey: ["stack", id],
    queryFn: () => stacksApi.get(id!),
    enabled: !isNew,
  });

  const agents = useQuery({
    queryKey: ["agents"],
    queryFn: () => agentsApi.list(),
    enabled: isNew,
  });
  const onlineAgents = (agents.data ?? []).filter((a) => a.status === "online");
  const remote = isNew && host !== "local";

  useEffect(() => {
    if (existing.data) {
      setName(existing.data.name);
      setDescription(existing.data.description ?? "");
      setYaml(existing.data.yaml || STARTER);
      setEnv(existing.data.env || "");
    }
  }, [existing.data]);

  const save = async (deploy: boolean) => {
    if (isNew && !name.trim()) {
      toast.error("Stack name is required");
      return;
    }
    setSaving(true);
    try {
      // Remote host: create the stack on the agent, then optionally start it.
      if (remote) {
        const aid = Number(host);
        const created = await agentsApi.createStack(aid, { name, yaml, env });
        qc.invalidateQueries({ queryKey: ["agent-stacks", aid] });
        toast.success("Saved");
        if (deploy) {
          // Stream the remote deploy live through the agent-deploy WS proxy.
          setDeployAgentId(aid);
          setDeployId(created.id);
          return;
        }
        navigate(`/hosts/${aid}/stacks/${created.id}`);
        return;
      }

      let stackId = id;
      if (isNew) {
        const created = await stacksApi.create({ name, description, yaml, env });
        stackId = created.id;
      } else {
        await stacksApi.update(id!, { name, description, yaml, env });
      }
      qc.invalidateQueries({ queryKey: ["stacks"] });
      qc.invalidateQueries({ queryKey: ["stack", stackId] });
      toast.success("Saved");
      if (deploy && stackId) {
        // Stream the deploy live in the console modal instead of a blind
        // spinner; navigation happens when the user closes it.
        setDeployId(stackId);
        return;
      }
      navigate(`/stacks/${stackId}`);
    } catch (err) {
      toast.error(apiErrorMessage(err));
    } finally {
      setSaving(false);
    }
  };

  const onDeploy = async () => {
    // The local port-conflict check doesn't apply to remote hosts.
    if (remote) {
      save(true);
      return;
    }
    setChecking(true);
    try {
      const found = await portsApi.conflicts(yaml, id);
      if (found.length > 0) {
        setConflicts(found);
        return;
      }
    } catch {
      /* if the check fails, fall through and let compose surface errors */
    } finally {
      setChecking(false);
    }
    save(true);
  };

  const convert = async () => {
    try {
      const { yaml: converted } = await stacksApi.convert(runCmd);
      setYaml(converted);
      setConvertOpen(false);
      setRunCmd("");
      toast.success("Converted to compose");
    } catch (err) {
      toast.error(apiErrorMessage(err));
    }
  };

  return (
    <div className="flex h-full flex-col space-y-3">
      <div className="flex flex-wrap items-center gap-3">
        <Input
          className="max-w-xs"
          placeholder="Stack name"
          value={name}
          onChange={(e) => setName(e.target.value)}
          disabled={!isNew}
        />
        <Input
          className="max-w-md flex-1"
          placeholder="Description (optional)"
          value={description}
          onChange={(e) => setDescription(e.target.value)}
        />
        {isNew && onlineAgents.length > 0 && (
          <select
            value={host}
            onChange={(e) => setHost(e.target.value)}
            className="rounded-lg border border-slate-300 bg-white px-3 py-2 text-sm dark:border-slate-600 dark:bg-slate-800"
            title="Target host"
          >
            <option value="local">This host</option>
            {onlineAgents.map((a) => (
              <option key={a.id} value={String(a.id)}>
                {a.name}
              </option>
            ))}
          </select>
        )}
        <Button variant="outline" onClick={() => setConvertOpen((v) => !v)}>
          <Wand2 className="h-4 w-4" /> Convert docker run
        </Button>
      </div>

      {convertOpen && (
        <Card className="flex items-center gap-2">
          <Input
            placeholder="docker run -d --name web -p 8080:80 nginx:alpine"
            value={runCmd}
            onChange={(e) => setRunCmd(e.target.value)}
          />
          <Button onClick={convert}>Convert</Button>
        </Card>
      )}

      <div className="flex gap-1 border-b border-slate-200 dark:border-slate-700">
        <TabBtn active={tab === "compose"} onClick={() => setTab("compose")}>
          <FileCode className="h-4 w-4" /> compose.yaml
        </TabBtn>
        <TabBtn active={tab === "env"} onClick={() => setTab("env")}>
          .env
        </TabBtn>
      </div>

      <div className="flex min-h-0 flex-1 gap-3">
        {/* Editor */}
        <div className="min-h-0 flex-1 overflow-hidden rounded-lg border border-slate-200 dark:border-slate-700">
          {tab === "compose" ? (
            <Editor
              height="100%"
              language="yaml"
              theme={theme === "dark" ? "vs-dark" : "light"}
              value={yaml}
              onChange={(v) => setYaml(v ?? "")}
              options={{ minimap: { enabled: false }, fontSize: 13, tabSize: 2 }}
            />
          ) : (
            <div className="h-full p-3">
              <EnvEditor value={env} onChange={setEnv} />
            </div>
          )}
        </div>

        {/* Helper panel (Volumes / GPU / Devices) */}
        {tab === "compose" && (
          <div className="w-[38%] min-w-[320px] overflow-hidden rounded-lg border border-slate-200 dark:border-slate-700">
            <EditorHelperPanel yaml={yaml} onYaml={setYaml} />
          </div>
        )}
      </div>

      <div className="flex justify-end gap-2">
        <Button variant="outline" onClick={() => save(false)} loading={saving}>
          <Save className="h-4 w-4" /> Save Draft
        </Button>
        <Button onClick={onDeploy} loading={saving || checking}>
          <Rocket className="h-4 w-4" /> Deploy
        </Button>
      </div>

      {conflicts && (
        <PortConflictDialog
          conflicts={conflicts}
          onContinue={() => {
            setConflicts(null);
            save(true);
          }}
          onCancel={() => setConflicts(null)}
        />
      )}

      {deployId && (
        <DeployConsole
          stackId={deployId}
          agentId={deployAgentId}
          onClose={() => {
            const sid = deployId;
            const aid = deployAgentId;
            setDeployId(null);
            setDeployAgentId(undefined);
            if (aid != null) {
              qc.invalidateQueries({ queryKey: ["agent-stacks", aid] });
              navigate(`/hosts/${aid}/stacks/${sid}`);
            } else {
              qc.invalidateQueries({ queryKey: ["stacks"] });
              qc.invalidateQueries({ queryKey: ["stack", sid] });
              navigate(`/stacks/${sid}`);
            }
          }}
        />
      )}
    </div>
  );
}

function TabBtn({
  active,
  onClick,
  children,
}: {
  active: boolean;
  onClick: () => void;
  children: React.ReactNode;
}) {
  return (
    <button
      onClick={onClick}
      className={
        active
          ? "flex items-center gap-1 border-b-2 border-accent px-4 py-2 text-sm font-medium text-accent dark:border-accent-dark dark:text-accent-dark"
          : "flex items-center gap-1 px-4 py-2 text-sm text-slate-500 hover:text-slate-700 dark:hover:text-slate-300"
      }
    >
      {children}
    </button>
  );
}