import { isAuthenticatedPrincipal } from "@ekklesia/contracts";
import {
  type AccountPreferences,
  type AccountStore,
  AccountStoreError,
  parseAccountPreferencesUpdate,
} from "@ekklesia/core/account";
import { CORE_ACCOUNT_SELF_MANAGE } from "@ekklesia/core/authorization";
import { type Context, Hono } from "hono";
import {
  type AuthorizationMiddlewareOptions,
  getAuthorizedPrincipal,
  requirePermission,
  requireTrustedOrigin,
} from "./authorization-middleware.js";
import { CORE_MUTATION_MAX_BODY_BYTES, platformBodyLimit } from "./body-limits.js";

export const ACCOUNT_PATH = "/api/v1/account";
export const ACCOUNT_PREFERENCES_PATH = `${ACCOUNT_PATH}/preferences`;

/** `GET /api/v1/account`: the signed-in person's own account, as the account area shows it. */
export interface AccountResponse {
  readonly name: string;
  readonly email: string;
  readonly preferences: AccountPreferences;
}

export interface CreateAccountRoutesOptions extends AuthorizationMiddlewareOptions {
  readonly store: AccountStore;
  readonly trustedOrigins: ReadonlySet<string>;
}

function sanitizedFailure(c: Context, status: 400 | 403 | 404 | 503, code: string): Response {
  c.header("Cache-Control", "no-store");
  return c.json({ code }, status);
}

/** Maps the store's own sanitized codes onto HTTP without inventing a second vocabulary. */
function storeFailure(
  c: Context,
  error: unknown,
  fallback: "ACCOUNT_READ_FAILED" | "ACCOUNT_WRITE_FAILED",
): Response {
  if (error instanceof AccountStoreError) {
    if (error.code === "ACCOUNT_NOT_FOUND") {
      return sanitizedFailure(c, 404, error.code);
    }
    if (error.code === "ACCOUNT_PREFERENCES_INVALID") {
      return sanitizedFailure(c, 400, "INVALID_REQUEST");
    }
    return sanitizedFailure(c, 503, error.code);
  }
  return sanitizedFailure(c, 503, fallback);
}

async function readJsonBody(c: Context): Promise<unknown> {
  try {
    return (await c.req.json()) as unknown;
  } catch {
    return undefined;
  }
}

/**
 * A signed-in person's own account (ADR 0062): who they are signed in as, and their own
 * preferences.
 *
 * ## Self-only by construction
 *
 * Neither route accepts a user id — not in the path, not in the query, not in the body. The account
 * is always the one the **session** names, so there is no request that could read or change anyone
 * else's, whatever permission the caller holds. A body that names any key besides a known
 * preference is refused whole.
 *
 * ## Authorization
 *
 * Both routes require `core.account.self.manage`, whose baseline is `authenticated`: every
 * signed-in person may manage their own account, and needs no church-management permission to do
 * so. An anonymous caller and a paired device are refused (`403`). Changing a preference is a
 * mutation like any other Core mutation: an exact trusted `Origin` and a bounded body are checked
 * before authorization work begins.
 *
 * ## What the browser learns
 *
 * Name, email, and preferences — exactly what the account area shows, and nothing else. Not the
 * account's image URL, verification state, timestamps, or any credential. Responses are per-person
 * and never cached.
 */
export function createAccountRoutes(options: CreateAccountRoutesOptions): Hono {
  const routes = new Hono();
  const requireSelf = requirePermission(options, CORE_ACCOUNT_SELF_MANAGE);
  const requireOrigin = requireTrustedOrigin(options.trustedOrigins);
  const mutationBodyLimit = platformBodyLimit(CORE_MUTATION_MAX_BODY_BYTES);

  routes.get(ACCOUNT_PATH, requireSelf, async (c) => {
    c.header("Cache-Control", "no-store");
    c.header("Vary", "Origin, Cookie");
    const principal = getAuthorizedPrincipal(c);
    // Unreachable through the `authenticated` baseline, which only a person satisfies; checked
    // again so the account read can never be keyed by anything but a person's own session.
    if (!isAuthenticatedPrincipal(principal)) {
      return sanitizedFailure(c, 403, "AUTHORIZATION_DENIED");
    }
    try {
      const account = await options.store.readAccount(principal.userId);
      if (!account) {
        return sanitizedFailure(c, 404, "ACCOUNT_NOT_FOUND");
      }
      return c.json(
        {
          email: account.email,
          name: account.name,
          preferences: {
            appearance: account.preferences.appearance,
            motion: account.preferences.motion,
          },
        } satisfies AccountResponse,
        200,
      );
    } catch (error) {
      return storeFailure(c, error, "ACCOUNT_READ_FAILED");
    }
  });

  routes.patch(
    ACCOUNT_PREFERENCES_PATH,
    requireOrigin,
    mutationBodyLimit,
    requireSelf,
    async (c) => {
      c.header("Cache-Control", "no-store");
      c.header("Vary", "Origin, Cookie");
      const principal = getAuthorizedPrincipal(c);
      if (!isAuthenticatedPrincipal(principal)) {
        return sanitizedFailure(c, 403, "AUTHORIZATION_DENIED");
      }
      const update = parseAccountPreferencesUpdate(await readJsonBody(c));
      if (!update) {
        return sanitizedFailure(c, 400, "INVALID_REQUEST");
      }
      try {
        const preferences = await options.store.updatePreferences(principal.userId, update);
        return c.json(
          {
            appearance: preferences.appearance,
            motion: preferences.motion,
          } satisfies AccountPreferences,
          200,
        );
      } catch (error) {
        return storeFailure(c, error, "ACCOUNT_WRITE_FAILED");
      }
    },
  );

  return routes;
}