/**
 * @file API client for communicating with the Elysium backend.
 * @copyright nhcarrigan
 * @license Naomi's Public License
 * @author Naomi Carrigan
 */
import type {
  AboutResponse,
  ApotheosisRequest,
  ApotheosisResponse,
  AuthResponse,
  BossChallengeRequest,
  BossChallengeResponse,
  BuyEchoUpgradeRequest,
  BuyEchoUpgradeResponse,
  BuyPrestigeUpgradeRequest,
  BuyPrestigeUpgradeResponse,
  CraftRecipeRequest,
  CraftRecipeResponse,
  ExploreClaimableResponse,
  ExploreCollectRequest,
  ExploreCollectResponse,
  ExploreStartRequest,
  ExploreStartResponse,
  ForceUnlocksResponse,
  LoadResponse,
  PrestigeRequest,
  PrestigeResponse,
  PublicProfileResponse,
  SaveRequest,
  SaveResponse,
  SyncNewContentResponse,
  TranscendenceRequest,
  TranscendenceResponse,
  UpdateProfileRequest,
  UpdateProfileResponse,
} from "@elysium/types";

const baseUrl = "/api";

const getToken = (): string | null => {
  return globalThis.localStorage.getItem("elysium_token");
};

/* eslint-disable @typescript-eslint/naming-convention -- HTTP header names require specific casing */
const buildHeaders = (): Record<string, string> => {
  const token = getToken();
  return {
    "Content-Type": "application/json",
    ...token !== null && token.length > 0
      ? { Authorization: `Bearer ${token}` }
      : {},
  };
};
/* eslint-enable @typescript-eslint/naming-convention -- HTTP header names require specific casing */

const fetchJson = async <T>(
  path: string,
  options?: RequestInit,
): Promise<T> => {
  const response = await fetch(`${baseUrl}${path}`, {
    ...options,
    headers: { ...buildHeaders(), ...options?.headers },
  });

  if (!response.ok) {
    /* eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- JSON error response requires type assertion */
    const errorBody = (await response.json().catch(() => {
      return { error: "Unknown error" };
    })) as Record<string, unknown>;
    const message
      = typeof errorBody.error === "string"
        ? errorBody.error
        : "Unknown error";
    throw new Error(message);
  }

  /* eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- JSON response requires type assertion */
  return await (response.json() as Promise<T>);
};

/**
 * Fetches the about information from the API.
 * @returns The about response data.
 */
const getAbout = async(): Promise<AboutResponse> => {
  return await fetchJson<AboutResponse>("/about");
};

/**
 * Fetches the Discord OAuth URL from the API.
 * @returns The authentication URL string.
 */
const getAuthUrl = async(): Promise<string> => {
  const data = await fetchJson<{ url: string }>("/auth/url");
  return data.url;
};

/**
 * Handles the Discord OAuth callback and stores the auth token.
 * @param code - The OAuth authorization code from Discord.
 * @returns The authentication response data.
 */
const handleAuthCallback = async(code: string): Promise<AuthResponse> => {
  const data = await fetchJson<AuthResponse>(`/auth/callback?code=${code}`);
  globalThis.localStorage.setItem("elysium_token", data.token);
  return data;
};

/**
 * Loads the current game state from the server.
 * @returns The load response containing the game state.
 */
const loadGame = async(): Promise<LoadResponse> => {
  return await fetchJson<LoadResponse>("/game/load");
};

/**
 * Resets all game progress on the server.
 * @returns The load response after reset.
 */
const resetProgress = async(): Promise<LoadResponse> => {
  return await fetchJson<LoadResponse>("/game/reset", { method: "POST" });
};

/**
 * Saves the current game state to the server.
 * @param body - The save request payload containing the game state.
 * @returns The save response data.
 */
const saveGame = async(body: SaveRequest): Promise<SaveResponse> => {
  return await fetchJson<SaveResponse>("/game/save", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Challenges a boss with the current game state.
 * @param body - The boss challenge request payload.
 * @returns The boss challenge response data.
 */
const challengeBoss = async(
  body: BossChallengeRequest,
): Promise<BossChallengeResponse> => {
  return await fetchJson<BossChallengeResponse>("/boss/challenge", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Triggers a prestige reset on the server.
 * @param body - The prestige request payload.
 * @returns The prestige response data.
 */
const prestige = async(body: PrestigeRequest): Promise<PrestigeResponse> => {
  return await fetchJson<PrestigeResponse>("/prestige", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Purchases a prestige upgrade on the server.
 * @param body - The buy prestige upgrade request payload.
 * @returns The buy prestige upgrade response data.
 */
const buyPrestigeUpgrade = async(
  body: BuyPrestigeUpgradeRequest,
): Promise<BuyPrestigeUpgradeResponse> => {
  return await fetchJson<BuyPrestigeUpgradeResponse>("/prestige/buy-upgrade", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Triggers a transcendence reset on the server.
 * @param body - The transcendence request payload.
 * @returns The transcendence response data.
 */
const transcend = async(
  body: TranscendenceRequest,
): Promise<TranscendenceResponse> => {
  return await fetchJson<TranscendenceResponse>("/transcendence", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Purchases an echo upgrade on the server.
 * @param body - The buy echo upgrade request payload.
 * @returns The buy echo upgrade response data.
 */
const buyEchoUpgrade = async(
  body: BuyEchoUpgradeRequest,
): Promise<BuyEchoUpgradeResponse> => {
  return await fetchJson<BuyEchoUpgradeResponse>("/transcendence/buy-upgrade", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Triggers an apotheosis reset on the server.
 * @param body - The apotheosis request payload.
 * @returns The apotheosis response data.
 */
const achieveApotheosis = async(
  body: ApotheosisRequest,
): Promise<ApotheosisResponse> => {
  return await fetchJson<ApotheosisResponse>("/apotheosis", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Starts an exploration in a given area.
 * @param body - The exploration start request payload.
 * @returns The exploration start response data.
 */
const startExploration = async(
  body: ExploreStartRequest,
): Promise<ExploreStartResponse> => {
  return await fetchJson<ExploreStartResponse>("/explore/start", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Collects the rewards from a completed exploration.
 * @param body - The exploration collect request payload.
 * @returns The exploration collect response data.
 */
const collectExploration = async(
  body: ExploreCollectRequest,
): Promise<ExploreCollectResponse> => {
  return await fetchJson<ExploreCollectResponse>("/explore/collect", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Checks whether a given exploration area is ready to claim on the server.
 * @param areaId - The area ID to check.
 * @returns Whether the exploration is claimable.
 */
const checkExplorationClaimable = async(
  areaId: string,
): Promise<ExploreClaimableResponse> => {
  return await fetchJson<ExploreClaimableResponse>(
    `/explore/claimable?areaId=${encodeURIComponent(areaId)}`,
  );
};

/**
 * Crafts a recipe on the server.
 * @param body - The craft recipe request payload.
 * @returns The craft recipe response data.
 */
const craftRecipe = async(
  body: CraftRecipeRequest,
): Promise<CraftRecipeResponse> => {
  return await fetchJson<CraftRecipeResponse>("/craft", {
    body:   JSON.stringify(body),
    method: "POST",
  });
};

/**
 * Sends a request to fix any missing unlocks in the player's game state.
 * @returns The corrected game state and counts of what was unlocked.
 */
const forceUnlocks = async(): Promise<ForceUnlocksResponse> => {
  return await fetchJson<ForceUnlocksResponse>("/debug/force-unlocks", {
    method: "POST",
  });
};

/**
 * Syncs any content added after the player's save was created into their save.
 * @returns The updated game state and counts of what was added per content type.
 */
const syncNewContent = async(): Promise<SyncNewContentResponse> => {
  return await fetchJson<SyncNewContentResponse>("/debug/sync-new-content", {
    method: "POST",
  });
};

/**
 * Performs a complete hard reset of the player's game state via the debug endpoint.
 * @returns The fresh game state as a LoadResponse.
 */
const debugHardReset = async(): Promise<LoadResponse> => {
  return await fetchJson<LoadResponse>("/debug/hard-reset", { method: "POST" });
};

/**
 * Fetches a public player profile by Discord ID.
 * @param discordId - The Discord ID of the player to look up.
 * @returns The public profile response data.
 */
const getPublicProfile = async(
  discordId: string,
): Promise<PublicProfileResponse> => {
  return await fetchJson<PublicProfileResponse>(`/profile/${discordId}`);
};

/**
 * Updates the current player's profile.
 * @param body - The update profile request payload.
 * @returns The update profile response data.
 */
const updateProfile = async(
  body: UpdateProfileRequest,
): Promise<UpdateProfileResponse> => {
  return await fetchJson<UpdateProfileResponse>("/profile", {
    body:   JSON.stringify(body),
    method: "PUT",
  });
};

export {
  achieveApotheosis,
  buyEchoUpgrade,
  buyPrestigeUpgrade,
  challengeBoss,
  checkExplorationClaimable,
  collectExploration,
  craftRecipe,
  debugHardReset,
  forceUnlocks,
  syncNewContent,
  getAbout,
  getAuthUrl,
  getPublicProfile,
  handleAuthCallback,
  loadGame,
  prestige,
  resetProgress,
  saveGame,
  startExploration,
  transcend,
  updateProfile,
};