import type {
  SendPaymentParams,
  SwapParams,
  AgentPayParams,
  QuoteParams,
  PaymentResult,
  BatchSendParams,
  BatchSendResult,
  ApprovalStatusParams,
  ApprovalStatusResult,
} from "./types";

export class PaymentSDK {
  constructor(private fetch: (path: string, init?: RequestInit) => Promise<Response>) {}

  // ── Send ──────────────────────────────────────────────────────────────────

  /** Send ETH or ERC-20 tokens to a single recipient */
  async send(params: SendPaymentParams): Promise<PaymentResult> {
    const r    = await this.fetch("/v1/agents/send", { method: "POST", body: JSON.stringify(params) });
    const data = await r.json() as any;
    if (!r.ok) throw new Error(data.error ?? "send failed");
    return data as PaymentResult;
  }

  /**
   * Send USDC to multiple recipients in one call.
   * Executes each transfer sequentially server-side.
   * Returns a per-recipient breakdown of successes and failures.
   *
   * @example
   * const result = await agent.payments.batchSend({
   *   recipients: [
   *     { to: "0xAlice", amount: "125", label: "1st place" },
   *     { to: "0xBob",   amount: "75",  label: "2nd place" },
   *   ],
   *   chain: "base",
   * });
   */
  async batchSend(params: BatchSendParams): Promise<BatchSendResult> {
    const r    = await this.fetch("/v1/agents/batch-send", { method: "POST", body: JSON.stringify(params) });
    const data = await r.json() as any;
    if (!r.ok) {
      // Server may not support batch endpoint yet — fall back to sequential sends
      if (r.status === 404) return this._batchSendFallback(params);
      throw new Error(data.error ?? "batch-send failed");
    }
    return data as BatchSendResult;
  }

  private async _batchSendFallback(params: BatchSendParams): Promise<BatchSendResult> {
    const sent:   BatchSendResult["sent"]   = [];
    const failed: BatchSendResult["failed"] = [];
    let total = 0;
    for (const recipient of params.recipients) {
      try {
        const res = await this.send({
          to:    recipient.to,
          amount: recipient.amount,
          chain: params.chain,
          token: params.token ?? "USDC",
        });
        if (res.status === "confirmed" || res.status === "completed" || res.txHash) {
          sent.push(recipient);
          total += parseFloat(recipient.amount) || 0;
        } else {
          failed.push({ recipient, error: res.message ?? "unknown" });
        }
      } catch (e: any) {
        failed.push({ recipient, error: e.message ?? "unknown" });
      }
    }
    return { sent, failed, total: total.toFixed(6), chain: params.chain ?? "base", token: params.token ?? "USDC" };
  }

  // ── Swap ─────────────────────────────────────────────────────────────────

  /** Execute a token swap via FluidSOR */
  async swap(params: SwapParams): Promise<PaymentResult> {
    const { otpCode, ...body } = params;
    const headers: Record<string, string> = {};
    if (otpCode) headers["X-OTP-Code"] = otpCode;
    const r    = await this.fetch("/v1/agents/swap", { method: "POST", body: JSON.stringify(body), headers });
    const data = await r.json() as any;
    if (data.error === "OTP_REQUIRED") throw new Error("OTP_REQUIRED: " + data.message);
    if (data.error === "OTP_INVALID")  throw new Error("OTP_INVALID: "  + data.message);
    if (!r.ok) throw new Error(data.error ?? "swap failed");
    return data as PaymentResult;
  }

  /** Get a price quote across 25+ DEX venues before executing */
  async quoteSwap(params: QuoteParams): Promise<unknown> {
    const { fromToken, toToken, amount, chain = "base" } = params;
    const r = await this.fetch(
      `/api/sor/wallet-quote?tokenIn=${fromToken}&tokenOut=${toToken}&amountIn=${amount}&network=${chain}`
    );
    const data = await r.json() as any;
    if (!r.ok) throw new Error(data.error ?? "quote failed");
    return data;
  }

  /** Estimate gas cost in USD before sending */
  async estimateGas(params: Pick<SendPaymentParams, "to" | "amount" | "chain" | "token">): Promise<unknown> {
    const r    = await this.fetch("/v1/agents/estimate-gas", { method: "POST", body: JSON.stringify(params) });
    const data = await r.json() as any;
    if (!r.ok) throw new Error(data.error ?? "estimate failed");
    return data;
  }

  // ── Agent pay (email-based) ────────────────────────────────────────────────

  /**
   * Pay another Fluid Wallet user by email.
   * Fluid resolves their wallet address server-side.
   */
  async agentPay(params: AgentPayParams): Promise<PaymentResult> {
    const r    = await this.fetch("/v1/agents/agent-pay", { method: "POST", body: JSON.stringify(params) });
    const data = await r.json() as any;
    if (!r.ok) throw new Error(data.error ?? "agent-pay failed");
    return data as PaymentResult;
  }

  // ── High-value approval polling ────────────────────────────────────────────

  /**
   * Poll the status of a high-value transaction that required wallet-owner approval.
   * When fluid_send returns status "pending_approval", use the approvalToken here.
   */
  async approvalStatus(params: ApprovalStatusParams): Promise<ApprovalStatusResult> {
    const r    = await this.fetch(`/v1/agents/approval?token=${encodeURIComponent(params.approvalToken)}`);
    const data = await r.json() as any;
    if (!r.ok) throw new Error(data.error ?? "approval status fetch failed");
    return data as ApprovalStatusResult;
  }
}