/**
 * Home cloud bootstrap. No React hooks: Home owns one effect and passes setters.
 *
 * The 20s timeout aborts this run and reveals the fatal screen. A login redirect
 * leaves that timer running so a failed navigation can still escape the spinner.
 */

import type { BirthTimeAssessmentPhase } from "@/components/birth-time-assessment-overlay";
import {
  guidedBirthTimePreview,
  isGuidedBirthTimePreview,
  previewRectificationJourney,
} from "@/lib/birth-time-guided-preview";
import { hydrateDeclaredWindowDraft } from "@/lib/birth-time-intake-model";
import type { JourneyClientResponse } from "@/lib/birth-time-journey-client";
import {
  SESSION_MISSING_NOTICE,
  clearLoginSessionReturn,
  writeSessionUrl,
  type BootstrapSessionSelection,
} from "@/lib/chat-session-url";
import { createStartGreeting } from "@/lib/starter-greeting";
import {
  HOME_BOOTSTRAP_SLOW_MS,
  resolveStarterHomeLandingSessionId,
  starterHomeLandingNeedsConsultation,
  type BootstrapPhase,
} from "@/lib/home-bootstrap";
import {
  ConsultationStatusError,
  LoginRedirectError,
  applyLegacySessionControls,
  createSession,
  fetchActiveConsultationStatus,
  fetchConsultationStatus,
  fetchModelCatalog,
  fetchSessionDetail,
  friendlyError,
  patchSessionModel,
  readSessions,
  readStoredPendingConsultation,
  redirectToLogin,
  resolveLookupBootstrap,
} from "@/lib/home-cloud-sync";
import { chartSnapshotForSession, missingProfileStep, readProfile } from "@/lib/home-profile";
import { peekSubjectCatalog, readCurrentSubjectId } from "@/lib/current-subject";
import { sessionMatchesSubject } from "@/lib/chat-profile-picker-model";
import {
  emptyProfile,
  pendingConsultationStorageKey,
  previewModelCatalog,
  timestamp,
  type Account,
  type ChatSession,
  type ConsultationStatus,
  type OnboardingStep,
  type Profile,
  type SessionReadResult,
  type StoredPendingConsultation,
} from "@/lib/home-types";
import type { PublicLanguageModelCatalog } from "@/lib/public-models";
import { dropRectificationStoredPending } from "@/lib/rectification-session-composer-guard";
import type { SessionListBoot } from "@/lib/session-list-context";
import { isUnsavedEmptyConsultation } from "@/lib/session-list-filter";
import { clearStaleClientReload } from "@/lib/stale-client-recovery";

export const HOME_BOOTSTRAP_TIMEOUT_MESSAGE = "连接云端服务超时。请检查网络后重试，或返回登录页重新建立会话。";

export type HomeBootstrapStorage = Pick<Storage, "getItem" | "removeItem">;

export type HomeBootstrapCommit = {
  setAccount: (account: Account) => void;
  setAccountError: (value: string) => void;
  setActiveSessionId: (id: string) => void;
  setBirthTimeAssessmentPhase: (phase: BirthTimeAssessmentPhase | null) => void;
  setBirthTimeJourney: (journey: JourneyClientResponse | null) => void;
  setBootstrapPhase: (phase: BootstrapPhase) => void;
  setGuidedJourneyPreview: (value: boolean) => void;
  setHydrated: (value: boolean) => void;
  setModelCatalog: (catalog: PublicLanguageModelCatalog | null) => void;
  setOnboardingStep: (step: OnboardingStep) => void;
  setProfile: (profile: Profile) => void;
  setProfileDraft: (profile: Profile) => void;
  setSessions: (sessions: ChatSession[]) => void;
  setSessionsCursor: (cursor: string | null) => void;
  setStartGreeting: (value: string) => void;
};

export type HomeBootstrapIo = {
  fetchModelCatalog: typeof fetchModelCatalog;
  fetchActiveConsultationStatus: typeof fetchActiveConsultationStatus;
  fetchConsultationStatus: typeof fetchConsultationStatus;
  fetchSessionDetail: typeof fetchSessionDetail;
  resolveLookupBootstrap: typeof resolveLookupBootstrap;
  patchSessionModel: typeof patchSessionModel;
  redirectToLogin: typeof redirectToLogin;
  clearStaleClientReload: typeof clearStaleClientReload;
  writeSessionUrl: typeof writeSessionUrl;
  clearLoginSessionReturn: typeof clearLoginSessionReturn;
  restoreConsultationRecovery: (
    session: ChatSession,
    requestId: string,
    stored?: StoredPendingConsultation | null,
  ) => void;
};

export type HomeBootstrapDeps = {
  sessionListReady: Promise<void>;
  waitForSessionList?: () => Promise<void>;
  sessionListBoot: () => SessionListBoot | null;
  uiPreview: { current: boolean };
  uiPreviewMode: { current: string | null };
  consultationStatusMissingCount: { current: number };
  isDevelopment: boolean;
  readSearch: () => string;
  storage: HomeBootstrapStorage;
  restoreConsultationRecovery: HomeBootstrapIo["restoreConsultationRecovery"];
  setComposerNotice: (notice: string) => void;
  commit: HomeBootstrapCommit;
  io?: Partial<HomeBootstrapIo>;
};

type AccountPhaseReady = {
  kind: "ready";
  nextAccount: Account;
  nextModelCatalog: PublicLanguageModelCatalog | null;
  nextProfile: Profile;
  nextSessions: ChatSession[];
  parsedSessions: SessionReadResult;
  reservedConsultation: ConsultationStatus | null;
  storedPending: StoredPendingConsultation | null;
  cursor: string | null;
};

type AccountPhaseResult = AccountPhaseReady | { kind: "stop" };

const defaultIo: Omit<HomeBootstrapIo, "restoreConsultationRecovery"> = {
  fetchModelCatalog,
  fetchActiveConsultationStatus,
  fetchConsultationStatus,
  fetchSessionDetail,
  resolveLookupBootstrap,
  patchSessionModel,
  redirectToLogin,
  clearStaleClientReload,
  writeSessionUrl,
  clearLoginSessionReturn,
};

function resolveIo(deps: HomeBootstrapDeps): HomeBootstrapIo {
  return {
    ...defaultIo,
    ...deps.io,
    restoreConsultationRecovery: deps.io?.restoreConsultationRecovery ?? deps.restoreConsultationRecovery,
  };
}

export async function runAccountPhase(
  deps: HomeBootstrapDeps,
  signal: AbortSignal,
): Promise<AccountPhaseResult> {
  const io = resolveIo(deps);
  const previewMode = deps.isDevelopment
    ? new URLSearchParams(deps.readSearch()).get("preview")
    : null;
  if (previewMode) {
    deps.uiPreview.current = true;
    deps.uiPreviewMode.current = previewMode;
    deps.commit.setGuidedJourneyPreview(true);
    if (previewMode === "error") {
      deps.commit.setAccountError(HOME_BOOTSTRAP_TIMEOUT_MESSAGE);
      deps.commit.setHydrated(true);
      return { kind: "stop" };
    }
    const isAssessmentLoadingPreview = previewMode === "birth-time-assessment-loading";
    const isCompletedCandidatePreview = previewMode === "birth-time-candidate-complete";
    const isRectificationPreview = isGuidedBirthTimePreview(previewMode);
    const previewJourney = isRectificationPreview
      ? guidedBirthTimePreview(previewMode)
      : previewRectificationJourney;
    const previewProfile: Profile = previewMode === "onboarding"
      ? emptyProfile
      : {
        ...emptyProfile,
        name: "林遥",
        date: "1990-06-15",
        time: isCompletedCandidatePreview ? "04:53" : isRectificationPreview || isAssessmentLoadingPreview ? "" : "12:30",
        reportedTime: isRectificationPreview ? "14:30" : isAssessmentLoadingPreview || isCompletedCandidatePreview ? "" : "12:30",
        birthTimeSource: isRectificationPreview ? "approximate" : isAssessmentLoadingPreview || isCompletedCandidatePreview ? "period_only" : "legacy_import",
        ...hydrateDeclaredWindowDraft({
          period: isAssessmentLoadingPreview || isCompletedCandidatePreview ? "early_morning" : "",
        }),
        birthTimeClue: "",
        uncertaintyBeforeMinutes: isRectificationPreview ? 30 : null,
        uncertaintyAfterMinutes: isRectificationPreview ? 30 : null,
        birthTimeStatus: isCompletedCandidatePreview
          ? "candidate"
          : isAssessmentLoadingPreview
          ? "rectifying"
          : previewJourney.snapshot.state === "candidate"
          || previewJourney.snapshot.state === "confirming"
          || previewJourney.snapshot.state === "ready"
            ? "candidate"
            : isRectificationPreview ? "rectifying" : "confirmed",
        rectificationCaseId: isRectificationPreview ? previewJourney.caseId : "",
        countryCode: "CN",
        provinceCode: "110000",
        cityCode: "110000-city",
        districtCode: "110101",
      };
    const previewMessages = previewMode === "conversation" || previewMode === "streaming" || previewMode === "partial"
      ? [
        { role: "user" as const, text: "未来半年是否适合换工作？" },
        { role: "assistant" as const, text: "可以先看职业方向、关键时间。\n同时评估现实风险。\n此处只展示本地预览，\n不调用真实星盘。" },
      ]
      : [];
    const previewSession: ChatSession = {
      id: "preview-session",
      title: previewMessages.length > 0 ? "未来半年是否适合换工作" : "新对话",
      theme: "career",
      modelId: previewModelCatalog.defaultModelId,
      messages: previewMessages,
      // session-clock-exempt: development preview fixture, not a stored session
      updatedAt: timestamp(),
      sessionType: "consultation",
      rectificationCaseId: null,
      chartProfileId: "self",
      chartProfileName: previewProfile.name.trim() || "我",
      chartProfileRole: "self",
      pinned: false,
      archivedAt: null,
      messagesHydrated: true,
    };
    deps.commit.setAccount({
      user: { id: "preview-user", email: "preview@local.test" },
      avatar: null,
      credits: 8,
      isAdmin: false,
      adminUrl: null,
      rectificationPriceCredits: 1,
      hasConfirmedBirthTime: previewProfile.birthTimeStatus === "confirmed",
      hasUsableBirthTime: previewProfile.birthTimeStatus === "accepted" || previewProfile.birthTimeStatus === "confirmed",
      activeSubscription: null,
      profile: previewProfile,
    });
    deps.commit.setModelCatalog(previewModelCatalog);
    deps.commit.setProfile(previewProfile);
    deps.commit.setProfileDraft(previewProfile);
    if (isRectificationPreview) {
      deps.commit.setBirthTimeJourney(previewJourney);
    }
    if (isAssessmentLoadingPreview) {
      deps.commit.setBirthTimeAssessmentPhase("assessing");
    }
    deps.commit.setOnboardingStep(isAssessmentLoadingPreview ? "birth" : missingProfileStep(previewProfile) ?? "name");
    deps.commit.setSessions([previewSession]);
    deps.commit.setActiveSessionId(previewSession.id);
    const previewGreeting = previewProfile.name.trim() ? createStartGreeting(previewProfile.name) : "";
    deps.commit.setStartGreeting(previewGreeting);
    deps.commit.setHydrated(true);
    return { kind: "stop" };
  }

  // Start independent reads before waiting for the provider so slow-network
  // latency is spent in parallel, not as a serial account -> model chain.
  const modelCatalogPromise = io.fetchModelCatalog(signal)
    .then((catalog) => ({ catalog, error: null as unknown }))
    .catch((error: unknown) => ({ catalog: null, error }));
  const activeStatusPromise = io.fetchActiveConsultationStatus(signal).catch((caught: unknown) => {
    if (caught instanceof Error && caught.name === "AbortError") throw caught;
    return null;
  });
  await (deps.waitForSessionList?.() ?? deps.sessionListReady);
  if (signal.aborted) return { kind: "stop" };
  const listBoot = deps.sessionListBoot();
  if (listBoot?.signedOut) {
    io.redirectToLogin();
    return { kind: "stop" };
  }
  if (!listBoot?.account || listBoot.error) throw new Error("session_list_unavailable");
  const nextAccount = listBoot.account;
  const modelCatalogResult = await modelCatalogPromise;
  if (modelCatalogResult.error) throw modelCatalogResult.error;
  const nextModelCatalog = modelCatalogResult.catalog;
  const nextProfile = readProfile(nextAccount.profile);
  const parsedSessions = readSessions(listBoot.rawRows, nextModelCatalog);
  let nextSessions = parsedSessions.sessions.length > 0 ? parsedSessions.sessions : listBoot.sessions;
  if (nextSessions.length === 0) {
    nextSessions = [createSession(
      nextModelCatalog?.defaultModelId ?? "",
      "consultation",
      chartSnapshotForSession(readCurrentSubjectId(), [...(peekSubjectCatalog() ?? [])], nextProfile),
    )];
  }
  nextSessions = applyLegacySessionControls(nextAccount.user.id, nextSessions);

  let reservedConsultation: ConsultationStatus | null = await activeStatusPromise;
  const storedPending = dropRectificationStoredPending(
    readStoredPendingConsultation(deps.storage.getItem(pendingConsultationStorageKey), nextSessions.map((session) => session.id)),
    nextSessions,
  );
  if (!storedPending) deps.storage.removeItem(pendingConsultationStorageKey);

  if (storedPending) {
    try {
      const status = await io.fetchConsultationStatus(
        storedPending.sessionId,
        storedPending.requestId,
        signal,
      );
      if (status.status === "reserved") {
        deps.consultationStatusMissingCount.current = 0;
        reservedConsultation = status;
      } else {
        deps.storage.removeItem(pendingConsultationStorageKey);
        reservedConsultation = null;
      }
    } catch (caught) {
      if (caught instanceof Error && caught.name === "AbortError") throw caught;
      deps.consultationStatusMissingCount.current = caught instanceof ConsultationStatusError && caught.status === 404 ? 1 : 0;
      reservedConsultation = {
        sessionId: storedPending.sessionId,
        requestId: storedPending.requestId,
        status: "reserved",
      };
    }
  }

  if (signal.aborted) return { kind: "stop" };
  return {
    kind: "ready",
    nextAccount,
    nextModelCatalog,
    nextProfile,
    nextSessions,
    parsedSessions,
    reservedConsultation,
    storedPending,
    cursor: listBoot.cursor,
  };
}

export async function resolveLanding(
  deps: HomeBootstrapDeps,
  signal: AbortSignal,
  ready: AccountPhaseReady,
): Promise<void> {
  const io = resolveIo(deps);
  const { writeSessionUrl, clearLoginSessionReturn, restoreConsultationRecovery } = io;
  const lookedUp = await io.resolveLookupBootstrap({
    sessions: ready.nextSessions,
    catalog: ready.nextModelCatalog,
    defaultSessionId: ready.nextSessions[0].id,
    signal,
    inSubjectScope: (session) => sessionMatchesSubject(session, readCurrentSubjectId()),
  });
  let nextSessions = lookedUp.sessions;
  const bootstrapSelection: BootstrapSessionSelection = lookedUp.selection;
  let landingSessionId = resolveStarterHomeLandingSessionId(
    nextSessions,
    bootstrapSelection.sessionId,
    bootstrapSelection.urlAction,
  );
  if (starterHomeLandingNeedsConsultation(nextSessions, landingSessionId, bootstrapSelection.urlAction)) {
    const homeSession = createSession(
      ready.nextModelCatalog?.defaultModelId ?? "",
      "consultation",
      chartSnapshotForSession(readCurrentSubjectId(), [...(peekSubjectCatalog() ?? [])], ready.nextProfile),
    );
    nextSessions = [homeSession, ...nextSessions];
    landingSessionId = homeSession.id;
  }
  const activeListed = nextSessions.find((session) => session.id === landingSessionId)
    ?? nextSessions[0];
  if (activeListed && !activeListed.messagesHydrated && activeListed.sessionType === "consultation") {
    try {
      const detailed = await io.fetchSessionDetail(activeListed.id, ready.nextModelCatalog, signal);
      if (detailed) {
        nextSessions = nextSessions.map((session) => session.id === detailed.id ? detailed : session);
      }
    } catch (caught) {
      if (caught instanceof Error && caught.name === "AbortError") throw caught;
      if (caught instanceof LoginRedirectError) return;
    }
  }
  if (signal.aborted) return;
  io.clearStaleClientReload(deps.storage);
  deps.commit.setSessionsCursor(ready.cursor);
  deps.commit.setAccount(ready.nextAccount);
  deps.commit.setModelCatalog(ready.nextModelCatalog);
  deps.commit.setProfile(ready.nextProfile);
  deps.commit.setProfileDraft(ready.nextProfile);
  deps.commit.setStartGreeting(ready.nextProfile.name.trim() ? createStartGreeting(ready.nextProfile.name) : "");
  deps.commit.setOnboardingStep(missingProfileStep(ready.nextProfile) ?? "name");
  deps.commit.setSessions(nextSessions);
  if (bootstrapSelection.urlAction === "new-chat") writeSessionUrl(null, "replace");
  deps.commit.setActiveSessionId(landingSessionId);
  if (bootstrapSelection.clearStoredReturn) clearLoginSessionReturn();
  if (bootstrapSelection.urlAction === "replace-clear") writeSessionUrl(null, "replace");
  if (bootstrapSelection.urlAction === "replace-selected") {
    const selected = nextSessions.find((session) => session.id === bootstrapSelection.sessionId);
    if (!selected || !isUnsavedEmptyConsultation(selected)) {
      writeSessionUrl(bootstrapSelection.sessionId, "replace");
    }
  }
  const reservedConsultation = ready.reservedConsultation;
  const storedPending = ready.storedPending;
  if (reservedConsultation?.status === "reserved") {
    const recoverySession = nextSessions.find((session) => session.id === reservedConsultation.sessionId);
    if (recoverySession) restoreConsultationRecovery(recoverySession, reservedConsultation.requestId, storedPending);
    if (bootstrapSelection.urlAction === "new-chat") {
      deps.commit.setActiveSessionId(landingSessionId);
      deps.setComposerNotice("");
    }
  }
  if (ready.parsedSessions.fallbackSessionIds.length > 0) {
    deps.setComposerNotice("此前选择的模型已下线，已切换为默认模型。");
  } else if (lookedUp.notice) {
    deps.setComposerNotice(lookedUp.notice);
  } else if (bootstrapSelection.missing) {
    deps.setComposerNotice(SESSION_MISSING_NOTICE);
  }
  deps.commit.setAccountError("");

  const fallbackCatalog = ready.nextModelCatalog;
  if (fallbackCatalog && ready.parsedSessions.fallbackSessionIds.length > 0) {
    try {
      await Promise.all(ready.parsedSessions.fallbackSessionIds.map((sessionId) =>
        io.patchSessionModel(sessionId, fallbackCatalog.defaultModelId, signal),
      ));
    } catch {
      if (!signal.aborted) {
        deps.setComposerNotice("已在当前页面切换为默认模型，但云端同步失败；刷新后可能需要重新选择。");
      }
    }
  }
}

export async function runHomeBootstrap(deps: HomeBootstrapDeps, signal: AbortSignal): Promise<void> {
  const controller = new AbortController();
  const onParentAbort = () => controller.abort();
  if (signal.aborted) onParentAbort();
  else signal.addEventListener("abort", onParentAbort);

  const bootstrapTimeout = window.setTimeout(() => {
    if (controller.signal.aborted) return;
    controller.abort();
    deps.commit.setAccountError(HOME_BOOTSTRAP_TIMEOUT_MESSAGE);
    deps.commit.setHydrated(true);
  }, HOME_BOOTSTRAP_SLOW_MS);
  const clearTimeoutOnParentAbort = () => {
    window.clearTimeout(bootstrapTimeout);
  };
  if (signal.aborted) clearTimeoutOnParentAbort();
  else signal.addEventListener("abort", clearTimeoutOnParentAbort);

  let redirectedToLogin = false;
  let bootstrapFailed = false;
  try {
    const ready = await runAccountPhase(deps, controller.signal);
    if (ready.kind === "ready") await resolveLanding(deps, controller.signal, ready);
  } catch (caught) {
    if (caught instanceof LoginRedirectError) {
      redirectedToLogin = true;
      return;
    }
    if ((caught as Error).name !== "AbortError" && !controller.signal.aborted) {
      bootstrapFailed = true;
      deps.commit.setAccountError(friendlyError(caught instanceof Error ? caught.message : "暂时无法读取云端数据"));
    }
  } finally {
    if (redirectedToLogin) return;
    signal.removeEventListener("abort", onParentAbort);
    signal.removeEventListener("abort", clearTimeoutOnParentAbort);
    window.clearTimeout(bootstrapTimeout);
    if (!controller.signal.aborted) {
      if (bootstrapFailed) deps.commit.setHydrated(true);
      else deps.commit.setBootstrapPhase("prepare");
    }
  }
}