import { apiFetch } from "./client";
import { getSettings } from "./settings";
import { getWorkspace, listWorkspaces } from "./workspaces";
import {
  WORKSPACE_POLICY_ERROR, WORKSPACE_SUMMARY_ERROR, WorkspaceSelectionError, workspacePolicyGate,
  workspacePreferences, type WorkspacePreference,
} from "../workspaces/drafts";
import type {
  Principal, ResumeSessionResult, SessionScope, SessionSummary, SessionDocument, UiResponse,
} from "./types";

type NewSessionInput = { question: string; name?: string } & Partial<WorkspacePreference>;

async function selectedPreferences(): Promise<WorkspacePreference> {
  const saved = workspacePreferences.load();
  if (saved.workspaceId && saved.provider && saved.model && saved.thinking) return saved;

  // A direct new-session entry point can run before the composer has mounted. Seed its
  // browser-local preferences from the legacy read-only defaults once, then keep them local.
  const legacy = await getSettings();
  return workspacePreferences.save({
    workspaceId: saved.workspaceId ?? legacy.workspace,
    provider: saved.provider ?? legacy.provider,
    model: saved.model ?? legacy.model,
    thinking: saved.thinking ?? legacy.thinking,
  });
}

function reconcileWorkspacePolicy(preferences: WorkspacePreference, allowed: readonly string[], defaultModel?: string) {
  if (allowed.length === 0) throw new WorkspaceSelectionError(WORKSPACE_POLICY_ERROR);
  const selected = preferences.provider && preferences.model
    ? `${preferences.provider}/${preferences.model}`
    : undefined;
  if (selected && allowed.includes(selected)) return preferences;
  const replacement = defaultModel && allowed.includes(defaultModel) ? defaultModel : allowed[0];
  const separator = replacement.indexOf("/");
  if (separator <= 0 || separator === replacement.length - 1) {
    throw new WorkspaceSelectionError(WORKSPACE_POLICY_ERROR);
  }
  return workspacePreferences.save({
    ...preferences,
    provider: replacement.slice(0, separator),
    model: replacement.slice(separator + 1),
  });
}

async function ensureWorkspaceSelectionPolicy(): Promise<WorkspacePreference> {
  while (true) {
    const preferences = workspacePreferences.load();
    const workspaceId = preferences.workspaceId;
    if (!workspaceId) return preferences;
    workspacePolicyGate.beginSummary(workspaceId);
    let workspace;
    try {
      workspace = (await listWorkspaces()).find((candidate) => candidate.id === workspaceId);
    } catch {
      if (workspacePreferences.load().workspaceId !== workspaceId) continue;
      workspacePolicyGate.rejectSummary(workspaceId);
      throw new WorkspaceSelectionError(WORKSPACE_SUMMARY_ERROR);
    }
    if (workspacePreferences.load().workspaceId !== workspaceId) continue;
    if (workspace && !workspace.revision) {
      workspacePolicyGate.reject(workspaceId);
      throw new WorkspaceSelectionError(WORKSPACE_POLICY_ERROR);
    }
    if (!workspace?.revision) {
      workspacePolicyGate.allowLegacy(workspaceId);
      return workspacePreferences.load();
    }
    workspacePolicyGate.select(workspaceId);
    const outcome = await Promise.race([
      getWorkspace(workspaceId).then(
        (record) => ({ kind: "record" as const, record }),
        () => ({ kind: "error" as const }),
      ),
      workspacePolicyGate.waitForCurrent(() => workspacePreferences.load()).then(
        (selection) => ({ kind: "selection" as const, selection }),
      ),
    ]);
    if (outcome.kind === "selection") {
      if (outcome.selection.workspaceId !== workspaceId) continue;
      return outcome.selection;
    }
    if (outcome.kind === "error") {
      if (workspacePreferences.load().workspaceId !== workspaceId) continue;
      workspacePolicyGate.reject(workspaceId);
      throw new WorkspaceSelectionError(WORKSPACE_POLICY_ERROR);
    }
    const { record } = outcome;
    if (workspacePreferences.load().workspaceId !== workspaceId) continue;
    let selection: WorkspacePreference;
    try {
      selection = reconcileWorkspacePolicy(
        preferences,
        record.workspace.llm_policy.allowed,
        record.workspace.llm_policy.default,
      );
    } catch (error) {
      workspacePolicyGate.reject(workspaceId);
      throw error;
    }
    workspacePolicyGate.resolve(workspaceId);
    if (workspacePreferences.load().workspaceId === workspaceId) return selection;
  }
}

export async function createSession(i: NewSessionInput) {
  await selectedPreferences();
  const selection = await ensureWorkspaceSelectionPolicy();
  return apiFetch<{ id: string }>("/sessions", {
    method: "POST",
    body: JSON.stringify({ ...i, ...selection }),
  });
}

/** Best-effort warm-up; callers must not await it before showing the composer. */
export const prewarmRuntime = () =>
  apiFetch<void>("/runtime/prewarm", { method: "POST" });

export const getMe = () => apiFetch<Principal>("/me");

export const listSessions = (scope: SessionScope = "mine") =>
  apiFetch<SessionSummary[]>(`/sessions?scope=${scope}`);

// eslint-disable-next-line @typescript-eslint/no-explicit-any
export const getSession = (id: string) => apiFetch<any>(`/sessions/${id}`);

export const postResponse = (id: string, uiResponse: UiResponse) =>
  apiFetch<void>(`/sessions/${id}/response`, {
    method: "POST",
    body: JSON.stringify({ ui_response: uiResponse }),
  });

export const postSteer = (id: string, text: string) =>
  apiFetch<void>(`/sessions/${id}/steer`, {
    method: "POST",
    body: JSON.stringify({ text }),
  });

export const closeSession = (id: string) =>
  apiFetch<void>(`/sessions/${id}/close`, { method: "POST" });

export const resumeSession = (id: string) =>
  apiFetch<ResumeSessionResult>(`/sessions/${id}/resume`, { method: "POST" });

export const renameSession = (id: string, name: string) =>
  apiFetch<void>(`/sessions/${id}/rename`, { method: "POST", body: JSON.stringify({ name }) });

export const setSessionGroup = (id: string, group: string) =>
  apiFetch<void>(`/sessions/${id}/group`, { method: "POST", body: JSON.stringify({ group }) });

export const archiveSession = (id: string) =>
  apiFetch<void>(`/sessions/${id}/archive`, { method: "POST" });

export const unarchiveSession = (id: string) =>
  apiFetch<void>(`/sessions/${id}/unarchive`, { method: "POST" });

export const deleteSession = (id: string) =>
  apiFetch<void>(`/sessions/${id}`, { method: "DELETE" });

export const getSessionDocuments = (id: string) =>
  apiFetch<SessionDocument[]>(`/sessions/${id}/documents`);

export async function checkDwhHealth(): Promise<{ ok: boolean }> {
  const timeout = new Promise<{ ok: false }>((r) => setTimeout(() => r({ ok: false }), 5000));
  try {
    return await Promise.race([
      apiFetch<{ ok: boolean; detail: string }>("/health/dwh"),
      timeout,
    ]);
  } catch {
    return { ok: false };
  }
}