import { useEffect, useState } from "react";
import { post } from "../api";
import { useAgents, useFetch } from "../hooks";
import { useT } from "../i18n";
import { ModelSelect } from "./ModelSelect";

interface DirListing {
  path: string;
  parent: string | null;
  workspace: string;
  dirs: { name: string; path: string; git: boolean }[];
}

const LAST_DIR = "codecraft.lastDir";

export function NewSession({ onMenu, onCreated }: { onMenu: () => void; onCreated: (id: string) => void }) {
  const t = useT();
  const [path, setPath] = useState<string>(localStorage.getItem(LAST_DIR) ?? "");
  const { data: listing, error: dirError } = useFetch<DirListing>(`/fs/dirs${path ? `?path=${encodeURIComponent(path)}` : ""}`);
  const config = useFetch<{ default_model?: string }>("/config").data;
  const [model, setModel] = useState("");
  const [agent, setAgent] = useState("build");
  const [prompt, setPrompt] = useState("");
  const [error, setError] = useState<string>();
  const [creating, setCreating] = useState(false);
  const agents = useAgents(listing?.path).filter((a) => a.mode === "primary");

  useEffect(() => {
    if (!model && config?.default_model) setModel(config.default_model);
  }, [config, model]);

  // A remembered directory that vanished: fall back to the workspace root.
  useEffect(() => {
    if (dirError && path) setPath("");
  }, [dirError, path]);

  const create = async () => {
    if (!listing) return;
    setCreating(true);
    setError(undefined);
    try {
      localStorage.setItem(LAST_DIR, listing.path);
      const s = await post<{ id: string }>("/sessions", { cwd: listing.path, model: model || undefined, agent });
      if (prompt.trim()) await post(`/sessions/${s.id}/prompt`, { text: prompt.trim() });
      onCreated(s.id);
    } catch (e: any) {
      setError(e.message);
      setCreating(false);
    }
  };

  const rel = listing ? listing.path.slice(listing.workspace.length) || "/" : "";

  return (
    <>
      <div className="topbar">
        <button className="ghost menu-btn" onClick={onMenu} aria-label={t("nav.menu")}>
          ☰
        </button>
        <div className="grow">
          <h1>{t("new.title")}</h1>
        </div>
      </div>
      <div className="page">
        <div className="page-inner" style={{ maxWidth: 760 }}>
          <div className="panel">
            <h3>{t("new.directory")}</h3>
            <div className="row" style={{ marginBottom: 8 }}>
              <code className="grow" style={{ flex: 1 }}>
                {rel}
              </code>
              {listing?.parent && (
                <button className="small" onClick={() => setPath(listing.parent!)}>
                  ↑ {t("new.up")}
                </button>
              )}
            </div>
            <div className="dir-list">
              {listing?.dirs.length === 0 && <div className="empty" style={{ padding: 16 }}>{t("new.noSubdirs")}</div>}
              {listing?.dirs.map((d) => (
                <button key={d.path} onClick={() => setPath(d.path)}>
                  <span>📁</span>
                  <span style={{ flex: 1 }}>{d.name}</span>
                  {d.git && <span className="chip">git</span>}
                </button>
              ))}
            </div>
          </div>

          <div className="panel">
            <div className="form">
              <label>{t("new.model")}</label>
              <ModelSelect value={model} onChange={setModel} />
              <label>{t("new.mode")}</label>
              <select value={agent} onChange={(e) => setAgent(e.target.value)}>
                {agents.map((a) => (
                  <option key={a.name} value={a.name}>
                    {a.name} – {a.description}
                  </option>
                ))}
              </select>
            </div>
          </div>

          <div className="panel">
            <h3>{t("new.firstPrompt")}</h3>
            <textarea
              style={{ width: "100%", minHeight: 110 }}
              value={prompt}
              placeholder={t("composer.placeholder")}
              onChange={(e) => setPrompt(e.target.value)}
              onKeyDown={(e) => {
                if (e.key === "Enter" && (e.ctrlKey || e.metaKey)) void create();
              }}
            />
          </div>
          {error && <div className="notice err">{error}</div>}
          <button className="primary" disabled={!listing || creating} onClick={create}>
            {t("new.start", { dir: rel })}
          </button>
        </div>
      </div>
    </>
  );
}