import { useCallback, useEffect, useMemo, useRef, useState } from "react";
import { Rail } from "@/components/Rail";
import { Transcript } from "@/components/Transcript";
import { Composer, type MainView, type SlashCommand } from "@/components/Composer";
import { Hero } from "@/components/Hero";
import { WorkspaceChip } from "@/components/WorkspaceChip";
import { ApprovalCard } from "@/components/ApprovalCard";
import { QuestionCard } from "@/components/QuestionCard";
import { SessionHeader } from "@/components/SessionHeader";
import { SettingsPanel } from "@/components/SettingsPanel";
import { PlanPanel } from "@/components/PlanPanel";
import { BashPanel } from "@/components/BashPanel";
import type { HermitMood } from "@/components/Icons";
import {
  answerConsent,
  answerQuestion,
  attachFile,
  cancelTurn,
  clearPending,
  compactSession,
  deleteSession,
  engineStatus,
  exportSession,
  getSettings,
  getTodo,
  getUsage,
  isShellTool,
  listBashRuns,
  listPending,
  listProviders,
  listSessions,
  listWorkspaceFiles,
  mockTurnsAllowed,
  newSession,
  onEngineEvent,
  onMenuEvent,
  openSession,
  pickFiles,
  pickWorkspace,
  pinSession,
  removePending,
  renameSession,
  sendTurn,
  setSessionFolder,
  setSettings,
  useProvider,
  type AttachmentInfo,
  type BashRun,
  type ChatItem,
  type ConsentRequest,
  type ProviderInfo,
  type QuestionRequest,
  type SessionInfo,
  type Settings,
  type UsageInfo,
} from "@/lib/bridge";
import frame from "@/dsh/layout/AppFrame.module.css";
import conv from "@/dsh/conversation/ConversationRoot.module.css";

const SIDEBAR_WIDTH = 280;

const UUID_RE =
  /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;

function displaySessionTitle(title?: string, id?: string): string {
  const t = (title || "").trim();
  if (!t || UUID_RE.test(t) || t === id) return "New session";
  return t;
}

export default function App() {
  const [sessions, setSessions] = useState<SessionInfo[]>([]);
  const [activeId, setActiveId] = useState<string | null>(null);
  const [items, setItems] = useState<ChatItem[]>([]);
  const [draft, setDraft] = useState("");
  const [busy, setBusy] = useState(false);
  const [query, setQuery] = useState("");
  const [settings, setSettingsState] = useState<Settings>({
    provider: "deepseek",
    model: "deepseek-flash",
    approval: "auto",
    workspace: ".",
    plan_mode: false,
    reasoning_effort: "high",
    font_size: "m",
    language: "zh",
  });
  const [consent, setConsent] = useState<ConsentRequest | null>(null);
  const [question, setQuestion] = useState<QuestionRequest | null>(null);
  const [showSettings, setShowSettings] = useState(false);
  const [status, setStatus] = useState("");
  const [todo, setTodo] = useState("");
  const [bashRuns, setBashRuns] = useState<BashRun[]>([]);
  const [view, setView] = useState<MainView>("chat");
  const [attachments, setAttachments] = useState<AttachmentInfo[]>([]);
  const [providers, setProviders] = useState<ProviderInfo[]>([]);
  const [usage, setUsage] = useState<UsageInfo>({
    prompt: 0,
    out: 0,
    cost: 0,
    priced: false,
    pct: 0,
  });
  const [fileSuggestions, setFileSuggestions] = useState<string[]>([]);
  const [dragging, setDragging] = useState(false);
  const [engine, setEngine] = useState("host");
  const convColRef = useRef<HTMLDivElement>(null);

  const hero = items.length === 0 && !busy && view === "chat";

  useEffect(() => {
    const el = convColRef.current;
    if (!el) return;
    const sync = () => {
      el.style.setProperty(
        "--dsh-conversation-column-width",
        `${el.clientWidth}px`,
      );
    };
    sync();
    const ro = new ResizeObserver(sync);
    ro.observe(el);
    return () => ro.disconnect();
  }, []);
  const agentMood: HermitMood = busy
    ? consent || question
      ? "thinking"
      : "coding"
    : "idle";

  const engineReady = engine === "engine";
  const sendBlocked = !engineReady && !mockTurnsAllowed();
  const sendBlockedReason = sendBlocked
    ? engine === "browser"
      ? "当前在浏览器预览（无 Tauri）。请用 apps/desktop/run-dev.sh 启动真引擎。"
      : "当前为 host（未链接 libcstcore）。请用 run-dev.sh（自动 --features engine），并在环境或设置中配置 DEEPSEEK_API_KEY。"
    : engineReady
      ? undefined
      : "演示 mock 已开启（hermit.allowMock）— 非真实引擎。";

  const refreshSessions = useCallback(async () => {
    const list = await listSessions();
    list.sort(
      (a, b) =>
        Number(!!b.pinned) - Number(!!a.pinned) || b.updated_at - a.updated_at,
    );
    setSessions(list);
  }, []);

  const refreshPending = useCallback(async () => {
    setAttachments(await listPending());
  }, []);

  const refreshBash = useCallback(async () => {
    setBashRuns(await listBashRuns());
  }, []);

  const applySettings = useCallback(async (next: Settings) => {
    const saved = await setSettings(next);
    setSettingsState(saved);
    document.documentElement.dataset.font = saved.font_size || "m";
    document.documentElement.dataset.lang = saved.language || "zh";
    return saved;
  }, []);

  const onPickWorkspace = useCallback(async () => {
    const path = await pickWorkspace();
    if (!path) return;
    await applySettings({ ...settings, workspace: path });
    await refreshSessions();
  }, [applySettings, refreshSessions, settings]);

  useEffect(() => {
    void (async () => {
      const s = await getSettings();
      setSettingsState(s);
      document.documentElement.dataset.font = s.font_size || "m";
      document.documentElement.dataset.lang = s.language || "zh";
      const st = await engineStatus();
      setEngine(st);
      setStatus(st === "engine" ? "engine ready" : st);
      setProviders(await listProviders());
      setUsage(await getUsage());
      const list = await listSessions();
      list.sort(
        (a, b) =>
          Number(!!b.pinned) - Number(!!a.pinned) || b.updated_at - a.updated_at,
      );
      setSessions(list);
      await refreshPending();
      // Never block first paint on ensure_live/open_session (can freeze GTK).
      // Start on empty hero; open the latest session after a tick.
      const forceHero =
        typeof location !== "undefined" &&
        new URLSearchParams(location.search).get("hero") === "1";
      setActiveId(null);
      setItems([]);
      if (forceHero) return;
      const first = list[0];
      if (!first) return;
      window.setTimeout(() => {
        void (async () => {
          try {
            setActiveId(first.id);
            setItems(await openSession(first.id));
            setTodo(await getTodo());
            setBashRuns(await listBashRuns());
          } catch (e) {
            console.error("openSession deferred failed", e);
            setActiveId(null);
            setItems([]);
          }
        })();
      }, 0);
    })();
  }, [refreshPending]);

  useEffect(() => {
    let un: (() => void) | undefined;
    void onEngineEvent((ev) => {
      if (ev.type === "assistant_delta") {
        setItems((prev) => {
          const last = prev[prev.length - 1];
          if (last && last.kind === "assistant") {
            return [
              ...prev.slice(0, -1),
              { ...last, text: last.text + ev.text },
            ];
          }
          return [
            ...prev,
            {
              kind: "assistant",
              id: `a${Date.now()}`,
              text: ev.text,
              ts: Date.now(),
            },
          ];
        });
      } else if (ev.type === "thought_delta") {
        setItems((prev) => {
          const last = prev[prev.length - 1];
          if (last && last.kind === "thought") {
            return [
              ...prev.slice(0, -1),
              { ...last, text: last.text + "\n" + ev.text },
            ];
          }
          return [
            ...prev,
            {
              kind: "thought",
              id: `th${Date.now()}`,
              text: ev.text,
              ts: Date.now(),
            },
          ];
        });
      } else if (ev.type === "tool_start") {
        setItems((prev) => [
          ...prev,
          {
            kind: "tool",
            id: ev.id,
            name: ev.name,
            status: "running",
            detail: ev.detail,
            ts: Date.now(),
          },
        ]);
        if (isShellTool(ev.name)) {
          setBashRuns((prev) => {
            if (prev.some((b) => b.id === ev.id)) return prev;
            return [
              ...prev,
              {
                id: ev.id,
                command: ev.detail || ev.name,
                status: "running",
                started_at: Date.now(),
              },
            ];
          });
        }
      } else if (ev.type === "tool_end") {
        setItems((prev) =>
          prev.map((it) =>
            it.kind === "tool" && it.id === ev.id
              ? {
                  ...it,
                  status: ev.status,
                  detail: ev.detail || it.detail,
                  output: ev.output ?? it.output,
                  exit_code: ev.exit_code ?? it.exit_code,
                }
              : it,
          ),
        );
        setBashRuns((prev) =>
          prev.map((b) =>
            b.id === ev.id
              ? {
                  ...b,
                  status: ev.status,
                  output: ev.output ?? b.output,
                  exit_code: ev.exit_code ?? b.exit_code,
                  ended_at: Date.now(),
                }
              : b,
          ),
        );
      } else if (ev.type === "consent") {
        setConsent(ev.req);
      } else if (ev.type === "question") {
        setQuestion(ev.req);
      } else if (ev.type === "todo") {
        setTodo(ev.text);
      } else if (ev.type === "status") {
        setStatus(ev.message);
      } else if (ev.type === "turn_end") {
        setBusy(false);
        setConsent(null);
        setQuestion(null);
        void refreshSessions();
        void refreshPending();
        void getUsage().then(setUsage);
        void getTodo().then(setTodo);
        void refreshBash();
        setActiveId((id) => {
          if (id && ev.ok) {
            void openSession(id).then(setItems);
          }
          return id;
        });
      } else if (ev.type === "error") {
        setBusy(false);
        setItems((prev) => [
          ...prev,
          {
            kind: "assistant",
            id: `err${Date.now()}`,
            text: `Error: ${ev.message}`,
            ts: Date.now(),
          },
        ]);
      }
    }).then((u) => {
      un = u;
    });
    return () => un?.();
  }, [refreshBash, refreshPending, refreshSessions]);

  useEffect(() => {
    let un: (() => void) | undefined;
    void onMenuEvent((id) => {
      if (id === "new_session") void onNew();
      else if (id === "open_workspace") void onPickWorkspace();
      else if (id === "settings") setShowSettings(true);
      else if (id === "view_plan") setView((v) => (v === "plan" ? "chat" : "plan"));
      else if (id === "view_bash") setView((v) => (v === "bash" ? "chat" : "bash"));
      else if (id === "about") setShowSettings(true);
    }).then((u) => {
      un = u;
    });
    return () => un?.();
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [onPickWorkspace]);

  const open = async (id: string) => {
    setActiveId(id);
    setItems(await openSession(id));
    setTodo(await getTodo());
    setBashRuns(await listBashRuns());
    setConsent(null);
    setQuestion(null);
    setView("chat");
  };

  const onNew = async () => {
    const s = await newSession();
    await refreshSessions();
    setActiveId(s.id);
    setItems([]);
    setConsent(null);
    setQuestion(null);
    setTodo("");
    setBashRuns([]);
    setView("chat");
  };

  const onAttach = async () => {
    const paths = await pickFiles();
    for (const p of paths) await attachFile(p);
    await refreshPending();
  };

  const onSend = async () => {
    const text = draft.trim();
    if ((!text && attachments.length === 0) || busy || consent || question) return;
    if (sendBlocked) return;
    setDraft("");
    setBusy(true);
    setView("chat");
    setItems((prev) => [
      ...prev,
      {
        kind: "user",
        id: `u${Date.now()}`,
        text: text || "(attachments)",
        ts: Date.now(),
      },
    ]);
    if (!activeId) {
      const s = await newSession();
      setActiveId(s.id);
      await refreshSessions();
    } else {
      setSessions((prev) =>
        prev.map((s) =>
          s.id === activeId &&
          (s.title === "New session" || s.title === "Welcome")
            ? {
                ...s,
                title: (text || "Attachments").slice(0, 48),
                updated_at: Date.now(),
              }
            : s,
        ),
      );
    }
    await sendTurn(text || "Please look at the attached files.");
  };

  const models = useMemo(() => {
    const base = ["deepseek-flash", "deepseek-chat", "deepseek-reasoner"];
    if (!base.includes(settings.model)) return [settings.model, ...base];
    return base;
  }, [settings.model]);

  const slashCommands: SlashCommand[] = useMemo(
    () => [
      { cmd: "/new", desc: "Start a new session", run: () => void onNew() },
      {
        cmd: "/model",
        desc: "Cycle model",
        run: () => {
          const i = models.indexOf(settings.model);
          const next = models[(i + 1) % models.length];
          void applySettings({ ...settings, model: next });
        },
      },
      {
        cmd: "/approval",
        desc: "Cycle approval mode",
        run: () => {
          const order: Settings["approval"][] = ["ask", "auto", "yolo"];
          const i = order.indexOf(settings.approval);
          void applySettings({
            ...settings,
            approval: order[(i + 1) % order.length],
          });
        },
      },
      {
        cmd: "/plan",
        desc: "Toggle plan panel",
        run: () => setView((v) => (v === "plan" ? "chat" : "plan")),
      },
      {
        cmd: "/bash",
        desc: "Toggle bash panel",
        run: () => setView((v) => (v === "bash" ? "chat" : "bash")),
      },
      {
        cmd: "/compact",
        desc: "Compact session context",
        run: async () => {
          const msg = await compactSession();
          const hist = activeId ? await openSession(activeId) : [];
          setItems([
            ...hist,
            {
              kind: "assistant",
              id: `c${Date.now()}`,
              text: msg,
              ts: Date.now(),
            },
          ]);
          setTodo(await getTodo());
        },
      },
      {
        cmd: "/todo",
        desc: "Refresh todo checklist",
        run: async () => {
          const t = await getTodo();
          setTodo(t);
          setView("plan");
        },
      },
      {
        cmd: "/provider",
        desc: "Cycle provider",
        run: async () => {
          const list =
            providers.length > 0 ? providers : await listProviders();
          if (list.length === 0) return;
          const i = list.findIndex((p) => p.name === settings.provider);
          const next = list[(i + 1) % list.length];
          await useProvider(next.name, next.model);
          setProviders(await listProviders());
          setSettingsState(await getSettings());
          setStatus(`provider · ${next.name}`);
        },
      },
      {
        cmd: "/clear",
        desc: "Clear pending attachments",
        run: async () => {
          await clearPending();
          await refreshPending();
        },
      },
      {
        cmd: "/rename",
        desc: "Rename current session",
        run: () => {
          if (!activeId) return;
          const cur = sessions.find((s) => s.id === activeId)?.title ?? "";
          const title = window.prompt("Rename session", cur);
          if (title?.trim()) {
            void renameSession(activeId, title.trim()).then(refreshSessions);
          }
        },
      },
      {
        cmd: "/export",
        desc: "Export transcript as Markdown",
        run: async () => {
          const md = await exportSession();
          await navigator.clipboard?.writeText(md).catch(() => undefined);
          setItems((prev) => [
            ...prev,
            {
              kind: "assistant",
              id: `e${Date.now()}`,
              text: "Exported Markdown copied to clipboard.",
              ts: Date.now(),
            },
          ]);
        },
      },
      {
        cmd: "/settings",
        desc: "Open settings",
        run: () => setShowSettings(true),
      },
    ],
    [
      activeId,
      applySettings,
      models,
      providers,
      refreshPending,
      refreshSessions,
      sessions,
      settings,
    ],
  );

  const active = sessions.find((s) => s.id === activeId);
  const sessionTitle = displaySessionTitle(active?.title, active?.id);
  const wsLabel =
    settings.workspace === "." || !settings.workspace
      ? "Choose workspace"
      : settings.workspace.split(/[/\\]/).filter(Boolean).pop() ||
        settings.workspace;

  const inputBar = consent ? (
    <ApprovalCard
      req={consent}
      onAnswer={(a) => {
        void answerConsent(consent.id, a);
        setConsent(null);
      }}
    />
  ) : question ? (
    <QuestionCard
      req={question}
      onAnswer={(a) => {
        void answerQuestion(question.id, a);
        setQuestion(null);
      }}
      onSkip={() => {
        void answerQuestion(question.id, "");
        setQuestion(null);
      }}
    />
  ) : (
    <Composer
      value={draft}
      busy={busy}
      settings={settings}
      models={models}
      attachments={attachments}
      usage={usage}
      slashCommands={slashCommands}
      fileSuggestions={fileSuggestions}
      view={view}
      hero={hero}
      dragging={dragging}
      sendBlocked={sendBlocked}
      sendBlockedReason={sendBlockedReason}
      onChange={setDraft}
      onSend={() => void onSend()}
      onStop={() => void cancelTurn()}
      onSettingsPatch={(patch) => {
        void applySettings({ ...settings, ...patch });
      }}
      onAttach={() => void onAttach()}
      onRemoveAttach={(id) => {
        void removePending(id).then(refreshPending);
      }}
      onQueryFiles={(q) => {
        void listWorkspaceFiles(q).then(setFileSuggestions);
      }}
      onInsert={() => undefined}
      onView={setView}
    />
  );

  /** DSH ConversationContent composerBar */
  const composerBar = (
    <div
      className={`${conv.composerStack}${hero ? ` ${conv.composerHero}` : ""}`}
    >
      {hero ? <Hero mood={agentMood} /> : null}
      {hero ? (
        <div className={conv.heroWorkspaceRow}>
          <WorkspaceChip
            workspace={settings.workspace}
            onPick={() => void onPickWorkspace()}
          />
          <span className="hermit-engine-chip" data-mode={engine}>
            {engine}
          </span>
        </div>
      ) : null}
      {inputBar}
    </div>
  );

  return (
    <div
      className={`${frame.frame} app-frame-fill`}
      style={{
        gridTemplateColumns: `${SIDEBAR_WIDTH}px minmax(0, 1fr) 0px`,
      }}
      data-rightbar-collapsed=""
      data-font={settings.font_size || "m"}
      onDragEnter={(e) => {
        e.preventDefault();
        setDragging(true);
      }}
      onDragOver={(e) => e.preventDefault()}
      onDragLeave={() => setDragging(false)}
      onDrop={(e) => {
        e.preventDefault();
        setDragging(false);
        const files = [...e.dataTransfer.files];
        void (async () => {
          for (const f of files) {
            const path = (f as File & { path?: string }).path;
            if (path) await attachFile(path);
          }
          await refreshPending();
        })();
      }}
    >
      <div className={frame.sidebarCol}>
        <Rail
          sessions={sessions}
          activeId={activeId}
          workspace={settings.workspace}
          query={query}
          engine={engine}
          onQuery={setQuery}
          onNew={() => void onNew()}
          onOpen={(id) => void open(id)}
          onRename={(id, title) => {
            void renameSession(id, title).then(refreshSessions);
          }}
          onDelete={(id) => {
            void (async () => {
              await deleteSession(id);
              await refreshSessions();
              if (activeId === id) {
                setActiveId(null);
                setItems([]);
              }
            })();
          }}
          onPin={(id) => {
            void pinSession(id).then(refreshSessions);
          }}
          onSetFolder={(id, folder) => {
            void setSessionFolder(id, folder).then(refreshSessions);
          }}
          onSettings={() => setShowSettings(true)}
          onPickWorkspace={() => void onPickWorkspace()}
        />
      </div>

      <div className={frame.centerCol}>
        <div className={frame.mainPanel}>
          <div
            ref={convColRef}
            className={`${conv.root} hermit-conversation-body`}
            data-phase={hero ? "hero" : "active"}
          >
            {!hero ? (
              <SessionHeader
                workspaceLabel={wsLabel}
                folder={active?.folder}
                title={sessionTitle}
                mood={agentMood}
                status={status && status !== engine ? status : undefined}
                engine={engine}
              />
            ) : null}

            <div className={conv.body}>
              <div className={conv.scrollBody} data-conversation-scroll="">
                {!hero ? (
                  <div className={conv.viewArea}>
                    {view === "plan" ? (
                      <PlanPanel
                        text={todo}
                        planMode={!!settings.plan_mode}
                        onClose={() => setView("chat")}
                        onTogglePlanMode={() =>
                          void applySettings({
                            ...settings,
                            plan_mode: !settings.plan_mode,
                          })
                        }
                      />
                    ) : view === "bash" ? (
                      <BashPanel
                        runs={bashRuns}
                        onClose={() => setView("chat")}
                      />
                    ) : (
                      <Transcript items={items} busy={busy} />
                    )}
                  </div>
                ) : null}
                <div className={conv.composerSeat} data-composer-seat="">
                  {composerBar}
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>

      {/* rightbar fixed closed — 0 track */}
      <div className={frame.rightbarCol} aria-hidden />

      {showSettings ? (
        <SettingsPanel
          settings={settings}
          providers={providers}
          engine={engine}
          onSave={(s) => {
            void applySettings(s);
          }}
          onUseProvider={(provider, model, key) => {
            void useProvider(provider, model, key).then(async () => {
              setProviders(await listProviders());
              setSettingsState(await getSettings());
            });
          }}
          onClose={() => setShowSettings(false)}
        />
      ) : null}
    </div>
  );
}