/**
 * AereCoreBookClient — typed helpers for AereCoreBookV0 native CLOB.
 *
 * Contract: aerenew/contracts/contracts/corebook/AereCoreBookV0.sol
 *
 * Post-R6 hardening notes:
 *  - `place()` is the GTC limit entrypoint; refuses CROSSING orders (use
 *    iocFill / placeWithSlippage for those).
 *  - `iocFill(side, worstPrice, qty)` — naive IOC sweep capped at worstPrice.
 *  - `placeWithSlippage(side, price, qty, tif, minBaseFilled, maxQuoteSpent,
 *     maxAvgPriceWei)` — REAL slippage protection. SDKs MUST prefer this.
 *  - `placeProtected(...)` adds a per-order cancelDelayBlocks so mempool
 *     races cannot front-run a maker's cancel.
 *  - BUY taker pays `principal + maxFee + 256-wei buffer`; maker receives
 *    FULL `quoteAmount` (no fee skim).
 *  - On transfer-revert (USDC blacklist, ERC777 hook) the recipient gets a
 *    claimable credit. Pull via `claim(wantBase)`.
 *  - When the book is fully empty, `sweepDust()` forwards leftover QUOTE
 *    (excluding pendingSinkFee + totalClaimableQuote) to AereSink.
 */
import type { RpcProvider } from '../sink/AereSinkClient.js';

export interface AereCoreBookConfig {
  address: `0x${string}`;
  provider: RpcProvider;
}

export type Side = 0 | 1; // BUY=0, SELL=1
export type TimeInForce = 0 | 1; // GTC=0, IOC=1

/* --------------------------------- selectors --------------------------------- */

const SEL = {
  // entrypoints
  place:                       '0x8121866a', // place(uint8,uint128,uint128,uint8)
  placeProtected:              '0x8af26684', // placeProtected(uint8,uint128,uint128,uint8,uint16)
  placeWithSlippage:           '0xf4526bbc', // placeWithSlippage(uint8,uint128,uint128,uint8,uint128,uint256,uint128)
  placeWithSlippageProtected:  '0xc0efac90', // placeWithSlippageProtected(uint8,uint128,uint128,uint8,uint128,uint256,uint16,uint128)
  iocFill:                     '0x5bbb981a', // iocFill(uint8,uint128,uint128)
  cancel:                      '0x81649d06', // cancel(uint128)
  flushFees:                   '0x313d8cb9', // flushFees()
  sweepDust:                   '0xa53df2e2', // sweepDust()
  claim:                       '0x2d81a78e', // claim(bool)
  // reads (selectors recomputed 2026-06-11 against AereCoreBookV0.sol — the
  // previous values for bestBid/bestAsk/pendingSinkFee + immutables were wrong)
  bestBid:                     '0x20c1614b', // bestBid()
  bestAsk:                     '0xcffb7d15', // bestAsk()
  pendingSinkFee:              '0x20a0e28c', // pendingSinkFee()
  totalClaimableQuote:         '0x17554eb7', // totalClaimableQuote()
  totalClaimableBase:          '0x200d51bc', // totalClaimableBase()
  claimableQuote:              '0x2d9cf134', // claimableQuote(address)
  claimableBase:               '0x22046da1', // claimableBase(address)
  TAKER_FEE_BPS:               '0x2057bfa0', // TAKER_FEE_BPS()
  PRICE_TICK:                  '0xaffabe45', // PRICE_TICK()
  LOT_SIZE:                    '0x7fee67a2', // LOT_SIZE()
  QUOTE_DECIMALS_FACTOR:       '0x3da2ad02', // QUOTE_DECIMALS_FACTOR()
  BASE_DECIMALS_FACTOR:        '0x43878833', // BASE_DECIMALS_FACTOR()
  PRICE_SCALE:                 '0xc33f59d3', // PRICE_SCALE()
  MAX_CANCEL_DELAY_BLOCKS:     '0xef8045a2', // MAX_CANCEL_DELAY_BLOCKS()
  DEFAULT_CANCEL_DELAY_BLOCKS: '0x3d81cedd', // DEFAULT_CANCEL_DELAY_BLOCKS()
} as const;

/* ------------------------------ encode helpers ------------------------------ */

function padUint(value: bigint | number, bytes: number = 32): string {
  const hex = BigInt(value).toString(16);
  return hex.padStart(bytes * 2, '0');
}

function padAddress(addr: `0x${string}`): string {
  return addr.slice(2).toLowerCase().padStart(64, '0');
}

function hexToBigInt(hex: string): bigint {
  if (!/^0x[0-9a-fA-F]+$/.test(hex)) throw new Error(`CoreBookClient: bad hex: ${hex}`);
  return BigInt(hex);
}

/* --------------------------------- client --------------------------------- */

export class AereCoreBookClient {
  readonly address: `0x${string}`;
  private readonly provider: RpcProvider;

  constructor(cfg: AereCoreBookConfig) {
    this.address = cfg.address;
    this.provider = cfg.provider;
  }

  /* ----------------------------- read methods ----------------------------- */

  async readBestBid(): Promise<bigint>          { return hexToBigInt(await this._call(SEL.bestBid)); }
  async readBestAsk(): Promise<bigint>          { return hexToBigInt(await this._call(SEL.bestAsk)); }
  async readPendingSinkFee(): Promise<bigint>   { return hexToBigInt(await this._call(SEL.pendingSinkFee)); }
  async readTakerFeeBps(): Promise<bigint>      { return hexToBigInt(await this._call(SEL.TAKER_FEE_BPS)); }
  async readPriceTick(): Promise<bigint>        { return hexToBigInt(await this._call(SEL.PRICE_TICK)); }
  async readLotSize(): Promise<bigint>          { return hexToBigInt(await this._call(SEL.LOT_SIZE)); }
  async readQuoteFactor(): Promise<bigint>      { return hexToBigInt(await this._call(SEL.QUOTE_DECIMALS_FACTOR)); }
  async readBaseFactor(): Promise<bigint>       { return hexToBigInt(await this._call(SEL.BASE_DECIMALS_FACTOR)); }
  async readPriceScale(): Promise<bigint>       { return hexToBigInt(await this._call(SEL.PRICE_SCALE)); }
  async readTotalClaimableQuote(): Promise<bigint> { return hexToBigInt(await this._call(SEL.totalClaimableQuote)); }
  async readTotalClaimableBase(): Promise<bigint>  { return hexToBigInt(await this._call(SEL.totalClaimableBase)); }

  async readClaimableQuote(user: `0x${string}`): Promise<bigint> {
    return hexToBigInt(await this._call(SEL.claimableQuote + padAddress(user)));
  }
  async readClaimableBase(user: `0x${string}`): Promise<bigint> {
    return hexToBigInt(await this._call(SEL.claimableBase + padAddress(user)));
  }

  /** Compute quote = price * qty * QUOTE_FACTOR / (PRICE_SCALE * BASE_FACTOR). */
  async computeQuote(price: bigint, qty: bigint): Promise<bigint> {
    const [quoteFactor, baseFactor, priceScale] = await Promise.all([
      this.readQuoteFactor(), this.readBaseFactor(), this.readPriceScale(),
    ]);
    return (price * qty * quoteFactor) / (priceScale * baseFactor);
  }

  /* -------------------------- write calldata builders -------------------------- */

  /**
   * GTC limit entrypoint — REFUSES crossing orders. For crossing use
   * `iocFill` or `placeWithSlippage`. Applies DEFAULT_CANCEL_DELAY_BLOCKS=2.
   */
  encodePlace(side: Side, price: bigint, quantity: bigint, tif: TimeInForce): `0x${string}` {
    return (SEL.place
      + padUint(side, 32) + padUint(price, 32) + padUint(quantity, 32) + padUint(tif, 32)) as `0x${string}`;
  }

  /** GTC + custom cancel-delay. Use placeWithSlippageProtected for crossing. */
  encodePlaceProtected(side: Side, price: bigint, quantity: bigint, tif: TimeInForce, cancelDelayBlocks: number): `0x${string}` {
    return (SEL.placeProtected
      + padUint(side, 32) + padUint(price, 32) + padUint(quantity, 32)
      + padUint(tif, 32) + padUint(cancelDelayBlocks, 32)) as `0x${string}`;
  }

  /**
   * IOC sweep capped at worstPrice. NO avg-price protection — use
   * placeWithSlippage with explicit maxAvgPriceWei for surgical-sandwich
   * protection.
   */
  encodeIocFill(side: Side, worstPrice: bigint, quantity: bigint): `0x${string}` {
    return (SEL.iocFill
      + padUint(side, 32) + padUint(worstPrice, 32) + padUint(quantity, 32)) as `0x${string}`;
  }

  /**
   * Recommended entrypoint for any crossing order. Caller MUST set
   * `maxAvgPriceWei` strictly tighter than `price` to get real sandwich
   * protection (e.g. price*0.995 for 50bps band).
   */
  encodePlaceWithSlippage(
    side: Side, price: bigint, quantity: bigint, tif: TimeInForce,
    minBaseFilled: bigint, maxQuoteSpent: bigint, maxAvgPriceWei: bigint,
  ): `0x${string}` {
    return (SEL.placeWithSlippage
      + padUint(side, 32) + padUint(price, 32) + padUint(quantity, 32) + padUint(tif, 32)
      + padUint(minBaseFilled, 32) + padUint(maxQuoteSpent, 32) + padUint(maxAvgPriceWei, 32)) as `0x${string}`;
  }

  /** Full protection: crossing + slippage + cancel-delay. */
  encodePlaceWithSlippageProtected(
    side: Side, price: bigint, quantity: bigint, tif: TimeInForce,
    minBaseFilled: bigint, maxQuoteSpent: bigint, cancelDelayBlocks: number, maxAvgPriceWei: bigint,
  ): `0x${string}` {
    return (SEL.placeWithSlippageProtected
      + padUint(side, 32) + padUint(price, 32) + padUint(quantity, 32) + padUint(tif, 32)
      + padUint(minBaseFilled, 32) + padUint(maxQuoteSpent, 32)
      + padUint(cancelDelayBlocks, 32) + padUint(maxAvgPriceWei, 32)) as `0x${string}`;
  }

  encodeCancel(orderId: bigint): `0x${string}` {
    return (SEL.cancel + padUint(orderId, 32)) as `0x${string}`;
  }

  encodeFlushFees(): `0x${string}` { return SEL.flushFees as `0x${string}`; }

  /** Permissionless dust sweep — ONLY succeeds when book is fully empty. */
  encodeSweepDust(): `0x${string}` { return SEL.sweepDust as `0x${string}`; }

  /**
   * Pull accumulated claimable balance after a failed transfer.
   * @param wantBase  true → claim BASE side; false → claim QUOTE side.
   */
  encodeClaim(wantBase: boolean): `0x${string}` {
    return (SEL.claim + padUint(wantBase ? 1 : 0, 32)) as `0x${string}`;
  }

  /* --------------------------- helper: recommended bands --------------------------- */

  /**
   * Returns recommended slippage parameters for a crossing order. The caller
   * provides desired band (default 50bps); we compute maxAvgPriceWei such
   * that the average fill cannot exceed it.
   */
  recommendedSlippage(
    side: Side, limitPrice: bigint, quantity: bigint, bpsBand: number = 50,
  ): { minBaseFilled: bigint; maxQuoteSpent: bigint; maxAvgPriceWei: bigint } {
    const band = BigInt(bpsBand);
    const maxAvg = side === 0
      ? (limitPrice * (10_000n - band)) / 10_000n
      : (limitPrice * (10_000n + band)) / 10_000n;
    return {
      minBaseFilled: 0n,
      maxQuoteSpent: (1n << 256n) - 1n,
      maxAvgPriceWei: maxAvg,
    };
  }

  /* ----------------------------- internals ------------------------------ */

  private async _call(data: string): Promise<string> {
    const result = await this.provider.request({
      method: 'eth_call',
      params: [{ to: this.address, data }, 'latest'],
    });
    if (typeof result !== 'string') throw new Error('CoreBookClient: bad eth_call');
    return result;
  }
}