import type { Address } from './types.js';

// These resource types are SDK-local declarations that mirror the shape of
// `Resource` from `@lifi/compose-spec`. They exist so the SDK can be used
// without directly depending on `@lifi/compose-spec` at the call site.
// The types are structurally compatible, so they are assignable to each other.

/** A resource declaration representing the chain's native token (e.g. ETH, MATIC). */
export interface NativeResource {
  readonly kind: 'native';
  readonly chainId: number;
}

/** A resource declaration representing an ERC-20 token at a specific address. */
export interface Erc20Resource {
  readonly kind: 'erc20';
  readonly token: Address;
  readonly chainId: number;
}

/** A token resource — either the chain's native token or an ERC-20. */
export type Resource = NativeResource | Erc20Resource;

/**
 * Creates a native token resource declaration.
 *
 * @param chainId - The EVM chain ID the native token belongs to.
 * @returns A {@link NativeResource} for use in flow input schemas.
 *
 * @example
 * ```ts
 * const builder = sdk.flow(1, {
 *   inputs: { eth: native(1) },
 * });
 * ```
 */
export const native = (chainId: number): NativeResource => ({
  kind: 'native',
  chainId,
});

/**
 * Creates an ERC-20 token resource declaration.
 *
 * @param token - The `0x`-prefixed contract address of the ERC-20 token.
 * @param chainId - The EVM chain ID the token is deployed on.
 * @returns An {@link Erc20Resource} for use in flow input schemas.
 *
 * @example
 * ```ts
 * const USDC = '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48';
 * const builder = sdk.flow(1, {
 *   inputs: { usdc: erc20(USDC, 1) },
 * });
 * ```
 */
export const erc20 = (token: Address, chainId: number): Erc20Resource => ({
  kind: 'erc20',
  token,
  chainId,
});