import { AbiEvent, AbiFunction, Address, Hash, Hex } from 'ox'
import {
  BlockNotFoundError,
  parseEventLogs,
  publicActions,
  TransactionReceiptNotFoundError,
} from 'viem'
import { Addresses } from 'viem/tempo'
import * as z from 'zod/mini'

import * as Schema from '../../Schema.js'
import * as Viem from '../../Viem.js'
import * as Action from '../Action.js'
import type * as Catalog from '../Catalog.js'
import * as Chain from '../Chain.js'
import * as RoutesProvider from '../Provider.js'
import type * as Transfer from '../Transfer.js'

const approve = AbiFunction.from('function approve(address spender, uint256 amount)')
const approvalEvent = AbiEvent.from(
  'event Approval(address indexed owner, address indexed spender, uint256 value)',
)
const defaultFetch: RoutesProvider.Fetch = (input, init) => globalThis.fetch(input, init)
const assets = {
  'eip155:1': '0xA0b86991c6218b36c1d19d4a2e9eb0cE3606eB48',
  'eip155:4217': '0x20C000000000000000000000b9537d11c60E8b50',
  'eip155:8453': '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913',
} as const
const defaultDestinationPool = '0x8c76e2f6c5ceda9aa7772e7eff30280226c44392'
const deployments = {
  'eip155:1': {
    eid: 30_101,
    endpoint: '0x1a44076050125825900e736c501f859c50fE728c',
  },
  'eip155:4217': {
    eid: 30_410,
    endpoint: '0x20Bb7C2E2f4e5ca2B4c57060d1aE2615245dCc9C',
  },
  'eip155:8453': {
    eid: 30_184,
    endpoint: '0x1a44076050125825900e736c501f859c50fE728c',
  },
} as const
const oftReceived = AbiEvent.from(
  'event OFTReceived(bytes32 indexed guid, uint32 srcEid, address indexed toAddress, uint256 amountReceivedLD)',
)
const oftSent = AbiEvent.from(
  'event OFTSent(bytes32 indexed guid, uint32 dstEid, address indexed fromAddress, uint256 amountSentLD, uint256 amountReceivedLD)',
)
const packetSent = AbiEvent.from(
  'event PacketSent(bytes encodedPayload, bytes options, address sendLibrary)',
)
const quoteOft = AbiFunction.from(
  'function quoteOFT((uint32 dstEid, bytes32 to, uint256 amountLD, uint256 minAmountLD, bytes extraOptions, bytes composeMsg, bytes oftCmd) sendParam) view returns ((uint256 minAmountLD, uint256 maxAmountLD) limit, (int256 feeAmountLD, string description)[] oftFeeDetails, (uint256 amountSentLD, uint256 amountReceivedLD) receipt)',
)
const quoteSend = AbiFunction.from(
  'function quoteSend((uint32 dstEid, bytes32 to, uint256 amountLD, uint256 minAmountLD, bytes extraOptions, bytes composeMsg, bytes oftCmd) sendParam, bool payInLzToken) view returns ((uint256 nativeFee, uint256 lzTokenFee) fee)',
)
const send = AbiFunction.from(
  'function send((uint32 dstEid, bytes32 to, uint256 amountLD, uint256 minAmountLD, bytes extraOptions, bytes composeMsg, bytes oftCmd) sendParam, (uint256 nativeFee, uint256 lzTokenFee) fee, address refundAddress) payable returns ((bytes32 guid, uint64 nonce, (uint256 nativeFee, uint256 lzTokenFee) fee) msgReceipt, (uint256 amountSentLD, uint256 amountReceivedLD) oftReceipt)',
)
const endpointNativeToken = AbiFunction.from('function nativeToken() view returns (address)')
const wrap = AbiFunction.from('function wrap(address token, address to, uint256 amount)')
const quoteTtlMs = 60_000
const maximumLogBlockRange = 10_000n
const transferEvent = AbiEvent.from(
  'event Transfer(address indexed from, address indexed to, uint256 value)',
)
const zeroAddress = '0x0000000000000000000000000000000000000000'

/** Stargate provider schemas. */
export namespace schema {
  /** Configuration captured from one selected Stargate route. */
  export const Configuration = z
    .strictObject({
      destinationPoolAddress: z.optional(
        z
          .string()
          .check(
            z.regex(/^0x[0-9a-fA-F]{40}$/),
            z.describe('Stargate pool contract on the destination chain.'),
          ),
      ),
      poolAddress: z
        .string()
        .check(
          z.regex(/^0x[0-9a-fA-F]{40}$/),
          z.describe('Stargate pool contract on the source chain.'),
        ),
      sourceEid: z.optional(
        z
          .number()
          .check(z.int(), z.positive(), z.describe('LayerZero endpoint ID for the source chain.')),
      ),
    })
    .check(z.describe('Stargate configuration for one provider route.'))
}

const transferProviderState = z.object({
  destinationBlockNumber: z.string().check(z.regex(/^\d+$/)),
  routeConfiguration: schema.Configuration,
  stargate: z.object({
    guid: Schema.Hash,
    sourceBlock: z.optional(
      z.object({
        hash: Schema.Hash,
        number: z.string().check(z.regex(/^\d+$/)),
      }),
    ),
    sourceEid: z.number().check(z.int(), z.positive()),
  }),
})

type Deployment = {
  alternateFee?: {
    paymentToken: Address.Address
    token: Address.Address
  }
  destinationEid: number
  destinationPool?: Address.Address | undefined
  pool: Address.Address
  sourceEid: number
  sourceEndpoint: Address.Address
  sourceToken: Address.Address
}

type SendParam = {
  amountLD: bigint
  composeMsg: Hex.Hex
  dstEid: number
  extraOptions: Hex.Hex
  minAmountLD: bigint
  oftCmd: Hex.Hex
  to: Hex.Hex
}

/** Creates a direct Stargate V2 OFT route provider. */
export function stargate(options: stargate.Options = {}) {
  const fetch = options.fetch ?? defaultFetch
  const now = options.now ?? (() => new Date())
  const resolveRpcUrls = options.resolveRpcUrls ?? ((chain: Chain.Chain) => chain.rpcUrls)

  return RoutesProvider.from({
    id: 'stargate',
    name: 'Stargate',
    async getQuote({ candidate, route }, signal) {
      const deployment = resolveDeployment({
        configuration: candidate.configuration,
        destinationChainId: route.destination.chain.id,
        destinationTokenAddress: route.destination.address,
        sourceChainId: route.source.chain.id,
        sourceTokenAddress: route.source.address,
      })
      const sampledAt = now()
      if (!deployment) return unavailable({ message: 'ROUTE_NOT_CONFIGURED', now: sampledAt })

      const sendParam = createSendParam({
        amount: candidate.sourceAmount.amount,
        destinationEid: deployment.destinationEid,
        minimumAmount: '0',
        recipient: quoteRecipient(),
        recipientChainId: route.destination.chain.id,
      })
      const [limit, feeDetails, receipt] = await rpcClient({
        chainId: Number(Chain.eip155Id(route.source.chain)),
        fetch,
        signal,
        urls: resolveRpcUrls(route.source.chain),
      }).readContract({
        abi: [quoteOft],
        address: deployment.pool,
        args: [sendParam],
        functionName: 'quoteOFT',
      })
      if (!isValidQuote({ amount: candidate.sourceAmount.amount, feeDetails, limit, receipt }))
        return unavailable({ message: 'NO_EXACT_ROUTE', now: sampledAt })

      return {
        destinationAmountMin: receipt.amountReceivedLD.toString(),
        destinationAmount: receipt.amountReceivedLD.toString(),
        quality: quality(),
        sampledAt: sampledAt.toISOString(),
        status: 'available',
      }
    },
    async prepareTransfer({ candidate, method, mode, recipient, sender, slippageBps }, signal) {
      if (
        method !== 'transaction' ||
        mode !== 'exactSource' ||
        !validRecipient(candidate.destinationChain.id, recipient) ||
        !Address.validate(sender, { strict: false })
      )
        throw new RoutesProvider.ProviderConfigurationError()

      const deployment = resolveDeployment({
        configuration: candidate.configuration,
        destinationChainId: candidate.destinationChain.id,
        destinationTokenAddress: candidate.destinationToken.address,
        sourceChainId: candidate.sourceChain.id,
        sourceTokenAddress: candidate.sourceToken.address,
      })
      if (!deployment) throw new RoutesProvider.ProviderUnavailableError()
      const rpc = rpcClient({
        chainId: Number(Chain.eip155Id(candidate.route.source.chain)),
        fetch,
        signal,
        urls: resolveRpcUrls(candidate.route.source.chain),
      })
      const quoteParam = createSendParam({
        amount: candidate.sourceAmount.amount,
        destinationEid: deployment.destinationEid,
        minimumAmount: '0',
        recipient,
        recipientChainId: candidate.destinationChain.id,
      })
      const [[limit, feeDetails, receipt], destinationBlock] = await Promise.all([
        rpc.readContract({
          abi: [quoteOft],
          address: deployment.pool,
          args: [quoteParam],
          functionName: 'quoteOFT',
        }),
        rpcClient({
          chainId: Number(Chain.eip155Id(candidate.route.destination.chain)),
          fetch,
          signal,
          urls: resolveRpcUrls(candidate.route.destination.chain),
        }).getBlock({ blockTag: 'finalized', includeTransactions: false }),
      ])
      if (!isValidQuote({ amount: candidate.sourceAmount.amount, feeDetails, limit, receipt }))
        throw new RoutesProvider.ProviderUnavailableError()
      const quotedMinimum =
        (receipt.amountReceivedLD * BigInt(10_000 - (slippageBps ?? 0))) / 10_000n
      // Route amount schemas require a positive minimum, including at 100% slippage.
      const destinationAmountMin = quotedMinimum > 0n ? quotedMinimum : 1n
      const sendParam = createSendParam({
        amount: candidate.sourceAmount.amount,
        destinationEid: deployment.destinationEid,
        minimumAmount: destinationAmountMin.toString(),
        recipient,
        recipientChainId: candidate.destinationChain.id,
      })
      const [endpointFeeToken, messagingFee] = await Promise.all([
        rpc.readContract({
          abi: [endpointNativeToken],
          address: deployment.sourceEndpoint,
          functionName: 'nativeToken',
        }),
        rpc.readContract({
          abi: [quoteSend],
          account: sender as Address.Address,
          address: deployment.pool,
          args: [sendParam, false],
          functionName: 'quoteSend',
        }),
      ])
      if (messagingFee.lzTokenFee !== 0n) throw new RoutesProvider.ProviderPayloadError()
      if (
        (deployment.alternateFee &&
          !Address.isEqual(endpointFeeToken, deployment.alternateFee.token)) ||
        (!deployment.alternateFee && !Address.isEqual(endpointFeeToken, zeroAddress))
      )
        throw new RoutesProvider.ProviderUnavailableError()

      const action = {
        calls: [
          {
            data: AbiFunction.encodeData(approve, [
              deployment.pool,
              BigInt(candidate.sourceAmount.amount),
            ]),
            to: deployment.sourceToken,
            value: '0x0',
          },
          // EndpointV2Alt charges an ERC-20 balance, so mint its fee token before the pool pulls it.
          ...(deployment.alternateFee && messagingFee.nativeFee > 0n
            ? [
                {
                  data: AbiFunction.encodeData(approve, [
                    deployment.alternateFee.token,
                    messagingFee.nativeFee,
                  ]),
                  to: deployment.alternateFee.paymentToken,
                  value: '0x0' as const,
                },
                {
                  data: AbiFunction.encodeData(wrap, [
                    deployment.alternateFee.paymentToken,
                    sender,
                    messagingFee.nativeFee,
                  ]),
                  to: deployment.alternateFee.token,
                  value: '0x0' as const,
                },
                {
                  data: AbiFunction.encodeData(approve, [deployment.pool, messagingFee.nativeFee]),
                  to: deployment.alternateFee.token,
                  value: '0x0' as const,
                },
              ]
            : []),
          {
            data: AbiFunction.encodeData(send, [sendParam, messagingFee, sender]),
            to: deployment.pool,
            value: deployment.alternateFee ? '0x0' : Hex.fromNumber(messagingFee.nativeFee),
          },
        ],
        type: 'evm:calls' as const,
      }
      validateAction({
        action,
        configuration: candidate.configuration,
        destinationAmountMin: destinationAmountMin.toString(),
        destinationChainId: candidate.destinationChain.id,
        destinationTokenAddress: candidate.destinationToken.address,
        recipient,
        sender,
        sourceAmount: candidate.sourceAmount.amount,
        sourceChainId: candidate.sourceChain.id,
        sourceTokenAddress: candidate.sourceToken.address,
      })

      const sampledAt = now()
      return {
        action,
        destinationAmountMin: destinationAmountMin.toString(),
        destinationAmount: receipt.amountReceivedLD.toString(),
        expiresAt: new Date(sampledAt.getTime() + quoteTtlMs).toISOString(),
        fees:
          messagingFee.nativeFee === 0n
            ? []
            : [
                {
                  amount: messagingFee.nativeFee.toString(),
                  side: 'source' as const,
                  token: feeToken(candidate.sourceChain.id),
                },
              ],
        providerState: {
          destinationBlockNumber: destinationBlock.number.toString(),
          routeConfiguration: candidate.configuration,
        },
        quality: quality(),
        sampledAt: sampledAt.toISOString(),
      }
    },
    validateTransferAction({ action, candidate, destinationAmountMin, recipient, sender }) {
      return validateAction({
        action,
        configuration: candidate.configuration,
        destinationAmountMin,
        destinationChainId: candidate.destinationChain.id,
        destinationTokenAddress: candidate.destinationToken.address,
        recipient,
        sender,
        sourceAmount: candidate.sourceAmount.amount,
        sourceChainId: candidate.sourceChain.id,
        sourceTokenAddress: candidate.sourceToken.address,
      })
    },
    async verifyDestinationDelivery(
      { destinationChain, providerState, sourceChain, transfer },
      signal,
    ) {
      const state = transferProviderState.safeParse(providerState)
      if (!state.success || !transfer.destinationAmount) return { type: 'invalid' }
      return verifyDestinationDelivery({
        configuration: state.data.routeConfiguration,
        destinationAmount: transfer.destinationAmount.baseUnits,
        destinationBlockNumber: state.data.destinationBlockNumber,
        destinationChain,
        destinationTokenAddress: transfer.destinationToken.address,
        fetch,
        guid: state.data.stargate.guid,
        recipient: transfer.recipient,
        rpcUrls: resolveRpcUrls(destinationChain),
        signal,
        sourceChainId: sourceChain.id,
        sourceTokenAddress: transfer.sourceToken.address,
      })
    },
    async verifySourceTransaction(
      {
        destinationChain,
        providerState,
        routeConfiguration,
        sourceChain,
        transactionHash,
        transfer,
      },
      signal,
    ) {
      if (
        transfer.method !== 'transaction' ||
        transfer.mode !== 'exactSource' ||
        (!transfer.destinationAmountMin && !transfer.destinationAmount) ||
        !transfer.sender
      )
        return { type: 'invalid' }
      const parsedState =
        providerState?.['stargate'] === undefined
          ? undefined
          : transferProviderState.safeParse(providerState)
      if (parsedState && !parsedState.success) return { type: 'invalid' }
      const state = parsedState?.data
      const configuration =
        state?.routeConfiguration ?? providerState?.['routeConfiguration'] ?? routeConfiguration
      const evidence = await verifySourceTransaction({
        alternateFeeAmount: quotedAlternateFeeAmount({
          sourceChainId: sourceChain.id,
          transfer,
        }),
        configuration,
        destinationAmountMin: (transfer.destinationAmountMin ?? transfer.destinationAmount!)
          .baseUnits,
        destinationChain,
        destinationTokenAddress: transfer.destinationToken.address,
        fetch,
        recipient: transfer.recipient,
        rpcUrls: resolveRpcUrls(sourceChain),
        sender: transfer.sender,
        signal,
        sourceAmount: transfer.sourceAmount.baseUnits,
        sourceBlock: state?.stargate.sourceBlock
          ? {
              hash: state.stargate.sourceBlock.hash,
              number: BigInt(state.stargate.sourceBlock.number),
            }
          : undefined,
        sourceChain,
        sourceTokenAddress: transfer.sourceToken.address,
        transactionHash,
        validAfter: transfer.quote.sampledAt,
      })
      if (evidence.type === 'invalid' || evidence.type === 'related') return evidence
      if (evidence.type === 'reorged') {
        if (!state) return { type: 'pending' }
        const { stargate: _stargate, ...providerState } = state
        return { providerState, type: 'reorged' }
      }
      if (evidence.type !== 'verified') return evidence
      if (
        state &&
        (!Hex.isEqual(evidence.guid, state.stargate.guid) ||
          evidence.sourceEid !== state.stargate.sourceEid ||
          evidence.destinationAmount !== transfer.destinationAmount?.baseUnits)
      )
        return { type: 'invalid' }
      const destinationBlockNumber =
        state?.destinationBlockNumber ??
        (typeof providerState?.['destinationBlockNumber'] === 'string' &&
        /^\d+$/.test(providerState['destinationBlockNumber'])
          ? providerState['destinationBlockNumber']
          : await blockNumberBefore({
              chain: destinationChain,
              fetch,
              rpcUrls: resolveRpcUrls(destinationChain),
              signal,
              timestamp: transfer.quote.sampledAt,
            }))
      return {
        destinationAmount: evidence.destinationAmount,
        providerState: {
          ...providerState,
          destinationBlockNumber,
          routeConfiguration: configuration,
          stargate: {
            guid: evidence.guid,
            sourceBlock: {
              hash: evidence.sourceBlock.hash,
              number: evidence.sourceBlock.number.toString(),
            },
            sourceEid: evidence.sourceEid,
          },
        },
        type: 'verified',
      }
    },
  })
}

export declare namespace stargate {
  /** Stargate provider options. */
  type Options = {
    /** Fetch implementation override for chain RPC requests. */
    fetch?: RoutesProvider.Fetch | undefined
    /** Clock override for deterministic tests. */
    now?: (() => Date) | undefined
    /** Resolves preferred RPC endpoints for each route chain. */
    resolveRpcUrls?: ((chain: Chain.Chain) => readonly string[]) | undefined
  }
}

/** Validates one direct Stargate action and returns its exact execution allowances. */
export function validateAction(options: validateAction.Options): validateAction.Result {
  try {
    const action = Action.schema.EvmCalls.parse(options.action)
    const deployment = resolveDeployment({
      configuration: options.configuration,
      destinationChainId: options.destinationChainId,
      destinationTokenAddress: options.destinationTokenAddress,
      sourceChainId: options.sourceChainId,
      sourceTokenAddress: options.sourceTokenAddress,
    })
    if (!deployment || ![2, 5].includes(action.calls.length))
      throw new RoutesProvider.ProviderPayloadError()
    const approval = action.calls[0]!
    const execution = action.calls.at(-1)!
    validateApproval({
      amount: BigInt(options.sourceAmount),
      call: approval,
      spender: deployment.pool,
      token: deployment.sourceToken,
    })
    const messagingFee = validateSend({
      data: execution!.data as Hex.Hex,
      destinationAmountMin: options.destinationAmountMin,
      destinationEid: deployment.destinationEid,
      nativeFee: deployment.alternateFee ? undefined : BigInt(execution.value),
      pool: deployment.pool,
      recipient: options.recipient,
      recipientChainId: options.destinationChainId,
      sender: options.sender,
      sourceAmount: options.sourceAmount,
      to: execution!.to as Address.Address,
    })
    if (!deployment.alternateFee) {
      if (action.calls.length !== 2) throw new RoutesProvider.ProviderPayloadError()
      return { nativeValues: [{ to: execution.to, value: execution.value }] }
    }
    if (BigInt(execution.value) !== 0n) throw new RoutesProvider.ProviderPayloadError()
    if (messagingFee.nativeFee === 0n) {
      if (action.calls.length !== 2) throw new RoutesProvider.ProviderPayloadError()
      return {}
    }
    if (action.calls.length !== 5) throw new RoutesProvider.ProviderPayloadError()
    const [paymentApproval, wrapping, feeApproval] = action.calls.slice(1, 4)
    validateApproval({
      amount: messagingFee.nativeFee,
      call: paymentApproval!,
      spender: deployment.alternateFee.token,
      token: deployment.alternateFee.paymentToken,
    })
    const [paymentToken, receiver, amount] = AbiFunction.decodeData(wrap, wrapping!.data as Hex.Hex)
    if (
      !Address.isEqual(wrapping!.to as Address.Address, deployment.alternateFee.token) ||
      BigInt(wrapping!.value) !== 0n ||
      !Address.isEqual(paymentToken, deployment.alternateFee.paymentToken) ||
      !Address.isEqual(receiver, options.sender as Address.Address) ||
      amount !== messagingFee.nativeFee
    )
      throw new RoutesProvider.ProviderPayloadError()
    validateApproval({
      amount: messagingFee.nativeFee,
      call: feeApproval!,
      spender: deployment.pool,
      token: deployment.alternateFee.token,
    })
    return {
      tokenApprovals: [
        {
          amount: messagingFee.nativeFee.toString(),
          spender: deployment.alternateFee.token,
          token: deployment.alternateFee.paymentToken,
        },
        {
          amount: messagingFee.nativeFee.toString(),
          spender: deployment.pool,
          token: deployment.alternateFee.token,
        },
      ],
    }
  } catch (cause) {
    if (cause instanceof RoutesProvider.ProviderPayloadError) throw cause
    throw new RoutesProvider.ProviderPayloadError()
  }
}

export declare namespace validateAction {
  /** Provider-specific constraints established by Stargate action validation. */
  type Result = {
    /** Exact native values independently validated against provider calldata. */
    nativeValues?: readonly Action.NativeValue[] | undefined
    /** Exact additional token approvals independently validated against provider calldata. */
    tokenApprovals?: readonly Action.TokenApproval[] | undefined
  }

  /** Expected route terms for one Stargate action. */
  type Options = {
    /** Prepared Stargate action. */
    action: Action.EvmCalls
    /** Stargate configuration for the selected route. */
    configuration?: Catalog.Configuration | undefined
    /** Minimum destination amount encoded in the send call. */
    destinationAmountMin: string
    /** Destination chain CAIP-2 id. */
    destinationChainId: string
    /** Curated destination token. */
    destinationTokenAddress: string
    /** Destination beneficiary. */
    recipient: string
    /** Source account and LayerZero refund recipient. */
    sender: string
    /** Exact source amount in base units. */
    sourceAmount: string
    /** Source chain CAIP-2 id. */
    sourceChainId: string
    /** Curated source token. */
    sourceTokenAddress: string
  }
}

/** Verifies a submitted Stargate source transaction against stored transfer terms. */
export async function verifySourceTransaction(
  options: verifySourceTransaction.Options,
): Promise<verifySourceTransaction.Result> {
  const deployment = resolveDeployment({
    configuration: options.configuration,
    destinationChainId: options.destinationChain.id,
    destinationTokenAddress: options.destinationTokenAddress,
    sourceChainId: options.sourceChain.id,
    sourceTokenAddress: options.sourceTokenAddress,
  })
  if (
    !deployment ||
    options.sourceChain.kind !== 'evm' ||
    !Hash.validate(options.transactionHash) ||
    !validRecipient(options.destinationChain.id, options.recipient) ||
    !Address.validate(options.sender, { strict: false })
  )
    return { type: 'invalid' }

  const rpc = rpcClient({
    chainId: Number(Chain.eip155Id(options.sourceChain)),
    fetch: options.fetch ?? defaultFetch,
    signal: options.signal,
    urls: options.rpcUrls ?? options.sourceChain.rpcUrls,
  })
  const hash = options.transactionHash as Hex.Hex
  const [chainId, receipt] = await Promise.all([
    rpc.getChainId(),
    rpc.getTransactionReceipt({ hash }).catch((cause) => {
      if (cause instanceof TransactionReceiptNotFoundError) return undefined
      throw cause
    }),
  ])
  if (chainId !== Number(Chain.eip155Id(options.sourceChain))) return { type: 'invalid' }
  const block =
    !receipt || receipt.blockNumber === null
      ? undefined
      : await rpc
          .getBlock({ blockNumber: receipt.blockNumber, includeTransactions: false })
          .catch((cause) => {
            if (cause instanceof BlockNotFoundError) return undefined
            throw cause
          })
  if (
    !receipt ||
    receipt.blockNumber === null ||
    !block ||
    !Hex.isEqual(block.hash, receipt.blockHash)
  ) {
    if (!options.sourceBlock) return { type: 'pending' }
    const finalized = await rpc.getBlock({ blockTag: 'finalized', includeTransactions: false })
    if (finalized.number < options.sourceBlock.number) return { type: 'pending' }
    const canonical = await rpc
      .getBlock({ blockNumber: options.sourceBlock.number, includeTransactions: false })
      .catch((cause) => {
        if (cause instanceof BlockNotFoundError) return undefined
        throw cause
      })
    if (!canonical || Hex.isEqual(canonical.hash, options.sourceBlock.hash))
      return { type: 'pending' }
    return { type: 'reorged' }
  }
  if (receipt.status !== 'success') return { type: 'invalid' }
  const validAfter = Math.floor(Date.parse(options.validAfter) / 1_000)
  if (!Number.isSafeInteger(validAfter) || block.timestamp < BigInt(validAfter))
    return { type: 'invalid' }

  const amount = BigInt(options.sourceAmount)
  const destinationAmountMin = BigInt(options.destinationAmountMin)
  const sourceEvents = parseEventLogs({ abi: [oftSent], logs: receipt.logs, strict: true }).filter(
    ({ address, args }) =>
      Address.isEqual(address, deployment.pool) &&
      args.dstEid === deployment.destinationEid &&
      Address.isEqual(args.fromAddress, options.sender as Address.Address) &&
      args.amountSentLD === amount &&
      args.amountReceivedLD >= destinationAmountMin,
  )
  const transfers = parseEventLogs({
    abi: [transferEvent],
    logs: receipt.logs,
    strict: true,
  }).filter(
    ({ address, args }) =>
      Address.isEqual(address, deployment.sourceToken) &&
      Address.isEqual(args.from, options.sender as Address.Address) &&
      Address.isEqual(args.to, deployment.pool) &&
      args.value === amount,
  )
  if (sourceEvents.length !== 1 || transfers.length !== 1) {
    const approvals = parseEventLogs({
      abi: [approvalEvent],
      logs: receipt.logs,
      strict: true,
    })
    const sourceApprovals = approvals.filter(
      ({ address, args }) =>
        Address.isEqual(address, deployment.sourceToken) &&
        Address.isEqual(args.owner, options.sender as Address.Address) &&
        Address.isEqual(args.spender, deployment.pool) &&
        args.value === amount,
    )
    if (sourceApprovals.length === 1) return { type: 'related' }
    if (!deployment.alternateFee || options.alternateFeeAmount === undefined)
      return { type: 'invalid' }
    const alternateFee = deployment.alternateFee
    const alternateFeeAmount = BigInt(options.alternateFeeAmount)
    const paymentApprovals = approvals.filter(
      ({ address, args }) =>
        Address.isEqual(address, alternateFee.paymentToken) &&
        Address.isEqual(args.owner, options.sender as Address.Address) &&
        Address.isEqual(args.spender, alternateFee.token) &&
        args.value === alternateFeeAmount,
    )
    if (paymentApprovals.length === 1) return { type: 'related' }
    const feeApprovals = approvals.filter(
      ({ address, args }) =>
        Address.isEqual(address, alternateFee.token) &&
        Address.isEqual(args.owner, options.sender as Address.Address) &&
        Address.isEqual(args.spender, deployment.pool) &&
        args.value === alternateFeeAmount,
    )
    if (feeApprovals.length === 1) return { type: 'related' }
    const relatedTransfers = parseEventLogs({
      abi: [transferEvent],
      logs: receipt.logs,
      strict: true,
    })
    const paymentTransfers = relatedTransfers.filter(
      ({ address, args }) =>
        Address.isEqual(address, alternateFee.paymentToken) &&
        Address.isEqual(args.from, options.sender as Address.Address) &&
        Address.isEqual(args.to, alternateFee.token) &&
        args.value === alternateFeeAmount,
    )
    const wrappedTransfers = relatedTransfers.filter(
      ({ address, args }) =>
        Address.isEqual(address, alternateFee.token) &&
        Address.isEqual(args.from, zeroAddress) &&
        Address.isEqual(args.to, options.sender as Address.Address) &&
        args.value === alternateFeeAmount,
    )
    return paymentTransfers.length === 1 && wrappedTransfers.length === 1
      ? { type: 'related' }
      : { type: 'invalid' }
  }
  const sourceEvent = sourceEvents[0]!
  const destinationAmount = sourceEvent.args.amountReceivedLD
  const guid = sourceEvent.args.guid
  // PacketV1's 113-byte header is followed by Stargate's type, asset id, recipient, and amount.
  const packets = parseEventLogs({ abi: [packetSent], logs: receipt.logs, strict: true }).filter(
    ({ address, args }) => {
      const packet = args.encodedPayload
      return (
        Address.isEqual(address, deployment.sourceEndpoint) &&
        Hex.size(packet) === 156 &&
        Hex.toNumber(Hex.slice(packet, 0, 1)) === 1 &&
        Hex.toNumber(Hex.slice(packet, 9, 13)) === deployment.sourceEid &&
        Hex.toNumber(Hex.slice(packet, 45, 49)) === deployment.destinationEid &&
        Hex.isEqual(Hex.slice(packet, 81, 113), guid) &&
        Hex.toNumber(Hex.slice(packet, 113, 114)) === 1 &&
        Hex.isEqual(
          Hex.slice(packet, 116, 148),
          recipientBytes32(options.destinationChain.id, options.recipient),
        ) &&
        Hex.toBigInt(Hex.slice(packet, 148, 156)) === destinationAmount
      )
    },
  )
  if (packets.length !== 1) return { type: 'invalid' }
  return {
    destinationAmount: destinationAmount.toString(),
    guid,
    sourceBlock: { hash: block.hash, number: block.number },
    sourceEid: deployment.sourceEid,
    type: 'verified',
  }
}

export declare namespace verifySourceTransaction {
  /** Canonical source block that originally contained the transaction. */
  type Block = {
    /** Source block hash. */
    hash: Hex.Hex
    /** Source block number. */
    number: bigint
  }

  /** Stored terms and chain access needed to verify one source transaction. */
  type Options = {
    /** Exact alternate fee quoted in the payment token's base units. */
    alternateFeeAmount?: string | undefined
    /** Stargate configuration for the selected route. */
    configuration: unknown
    /** Minimum destination amount committed by the provider action. */
    destinationAmountMin: string
    /** Destination chain and address format. */
    destinationChain: Chain.Chain
    /** Curated destination token. */
    destinationTokenAddress: string
    /** Fetch implementation override for chain RPC requests. */
    fetch?: RoutesProvider.Fetch | undefined
    /** Destination beneficiary encoded in the Stargate send. */
    recipient: string
    /** Preferred source-chain RPC endpoints. */
    rpcUrls?: readonly string[] | undefined
    /** Source account and LayerZero refund recipient. */
    sender: string
    /** Optional request cancellation signal. */
    signal?: AbortSignal | undefined
    /** Exact source amount in base units. */
    sourceAmount: string
    /** Canonical block captured during initial verification. */
    sourceBlock?: Block | undefined
    /** Source chain and RPC endpoints. */
    sourceChain: Chain.Chain
    /** Curated source token. */
    sourceTokenAddress: string
    /** Submitted EVM transaction hash. */
    transactionHash: string
    /** Earliest accepted source block timestamp. */
    validAfter: string
  }

  /** Source transaction verification outcome. */
  type Result =
    | { type: 'invalid' }
    | { type: 'pending' }
    | { type: 'related' }
    | { type: 'reorged' }
    | {
        destinationAmount: string
        guid: Hex.Hex
        sourceBlock: Block
        sourceEid: number
        type: 'verified'
      }
}

function quotedAlternateFeeAmount(options: quotedAlternateFeeAmount.Options) {
  if (options.sourceChainId !== 'eip155:4217') return undefined
  const fees = options.transfer.fees.filter(
    (fee) =>
      fee.side === 'source' &&
      fee.type === 'provider' &&
      Address.validate(fee.token.address, { strict: false }) &&
      Address.isEqual(fee.token.address as Address.Address, Addresses.pathUsd),
  )
  return fees.length === 1 ? fees[0]!.amount.baseUnits : undefined
}

declare namespace quotedAlternateFeeAmount {
  type Options = {
    sourceChainId: string
    transfer: Transfer.Snapshot
  }
}

/** Finds and verifies the included Stargate delivery directly on the destination chain. */
export async function verifyDestinationDelivery(
  options: verifyDestinationDelivery.Options,
): Promise<verifyDestinationDelivery.Result> {
  const deployment = resolveDeployment({
    configuration: options.configuration,
    destinationChainId: options.destinationChain.id,
    destinationTokenAddress: options.destinationTokenAddress,
    sourceChainId: options.sourceChainId,
    sourceTokenAddress: options.sourceTokenAddress,
  })
  if (
    !deployment ||
    !deployment.destinationPool ||
    options.destinationChain.kind !== 'evm' ||
    !/^\d+$/.test(options.destinationBlockNumber) ||
    !Hash.validate(options.guid) ||
    !Address.validate(options.recipient, { strict: false })
  )
    return { type: 'invalid' }

  const destinationPool = deployment.destinationPool
  const rpc = rpcClient({
    chainId: Number(Chain.eip155Id(options.destinationChain)),
    fetch: options.fetch ?? defaultFetch,
    signal: options.signal,
    urls: options.rpcUrls ?? options.destinationChain.rpcUrls,
  })
  // Tempo completion favors latency over reorg protection; other destinations retain finality.
  const blockTag = options.destinationChain.id === 'eip155:4217' ? 'latest' : 'finalized'
  const [chainId, head] = await Promise.all([
    rpc.getChainId(),
    rpc.getBlock({ blockTag, includeTransactions: false }),
  ])
  if (chainId !== Number(Chain.eip155Id(options.destinationChain))) return { type: 'invalid' }
  const amount = BigInt(options.destinationAmount)
  const discovered = await (async () => {
    for (
      let fromBlock = BigInt(options.destinationBlockNumber);
      fromBlock <= head.number;
      fromBlock += maximumLogBlockRange
    ) {
      const toBlock = fromBlock + maximumLogBlockRange - 1n
      const logs = await rpc.getLogs({
        address: destinationPool,
        args: { guid: options.guid, toAddress: options.recipient as Address.Address },
        event: oftReceived,
        fromBlock,
        strict: true,
        toBlock: toBlock > head.number ? head.number : toBlock,
      })
      const matches = logs.filter(
        ({ args, transactionHash }) =>
          transactionHash &&
          args.srcEid === deployment.sourceEid &&
          args.amountReceivedLD === amount,
      )
      if (logs.length !== matches.length || matches.length > 1) return { type: 'invalid' as const }
      if (matches[0]?.transactionHash)
        return { transactionHash: matches[0].transactionHash, type: 'found' as const }
    }
    return { type: 'pending' as const }
  })()
  if (discovered.type !== 'found') return discovered
  const { transactionHash } = discovered
  const receipt = await rpc.getTransactionReceipt({ hash: transactionHash }).catch((cause) => {
    if (cause instanceof TransactionReceiptNotFoundError) return undefined
    throw cause
  })
  if (!receipt || receipt.blockNumber === null) return { type: 'pending' }
  if (receipt.status !== 'success' || receipt.blockNumber > head.number) return { type: 'invalid' }

  const transfers = parseEventLogs({
    abi: [transferEvent],
    logs: receipt.logs,
    strict: true,
  }).filter(
    ({ address, args }) =>
      Address.isEqual(address, options.destinationTokenAddress as Address.Address) &&
      Address.isEqual(
        args.from,
        options.destinationChain.id === 'eip155:4217' ? zeroAddress : destinationPool,
      ) &&
      Address.isEqual(args.to, options.recipient as Address.Address) &&
      args.value === amount,
  )
  if (transfers.length !== 1) return { type: 'invalid' }
  return { transactionHash, type: 'verified' }
}

export declare namespace verifyDestinationDelivery {
  /** Stored terms and chain access needed to discover and verify one delivery. */
  type Options = {
    /** Stargate configuration for the selected route. */
    configuration: unknown
    /** Exact destination amount in base units. */
    destinationAmount: string
    /** Destination block captured before the source transaction was broadcast. */
    destinationBlockNumber: string
    /** Destination chain and RPC endpoints. */
    destinationChain: Chain.Chain
    /** Curated destination token. */
    destinationTokenAddress: string
    /** Fetch implementation override for destination RPC requests. */
    fetch?: RoutesProvider.Fetch | undefined
    /** GUID emitted by the verified source Stargate pool. */
    guid: Hex.Hex
    /** Destination beneficiary. */
    recipient: string
    /** Preferred destination-chain RPC endpoints. */
    rpcUrls?: readonly string[] | undefined
    /** Optional request cancellation signal. */
    signal?: AbortSignal | undefined
    /** Source chain CAIP-2 id. */
    sourceChainId: string
    /** Curated source token. */
    sourceTokenAddress: string
  }

  /** Destination delivery verification outcome. */
  type Result =
    | { type: 'invalid' }
    | { type: 'pending' }
    | { transactionHash: Hex.Hex; type: 'verified' }
}

function rpcClient(options: rpcClient.Options) {
  if (options.urls.length === 0) throw new RoutesProvider.ProviderConfigurationError()
  return Viem.createEvmClient(options).extend(publicActions)
}

declare namespace rpcClient {
  type Options = {
    chainId: number
    fetch: RoutesProvider.Fetch
    signal?: AbortSignal | undefined
    urls: readonly string[]
  }
}

async function blockNumberBefore(options: blockNumberBefore.Options) {
  if (options.chain.kind !== 'evm') throw new RoutesProvider.ProviderConfigurationError()
  const timestamp = Date.parse(options.timestamp)
  if (!Number.isFinite(timestamp)) throw new RoutesProvider.ProviderPayloadError()
  const rpc = rpcClient({
    chainId: Number(Chain.eip155Id(options.chain)),
    fetch: options.fetch,
    signal: options.signal,
    urls: options.rpcUrls ?? options.chain.rpcUrls,
  })
  const [chainId, finalized] = await Promise.all([
    rpc.getChainId(),
    rpc.getBlock({ blockTag: 'finalized', includeTransactions: false }),
  ])
  if (chainId !== Number(Chain.eip155Id(options.chain)))
    throw new RoutesProvider.ProviderConfigurationError()

  const target = BigInt(Math.floor(timestamp / 1_000) - 1)
  let lower = 0n
  let upper = finalized.number
  while (lower < upper) {
    const middle = (lower + upper + 1n) / 2n
    const block = await rpc.getBlock({ blockNumber: middle, includeTransactions: false })
    if (block.timestamp <= target) lower = middle
    else upper = middle - 1n
  }
  return lower.toString()
}

declare namespace blockNumberBefore {
  type Options = {
    /** Destination chain whose block history is searched. */
    chain: Chain.Chain
    /** Fetch implementation used for RPC requests. */
    fetch: RoutesProvider.Fetch
    /** Preferred chain RPC endpoints. */
    rpcUrls?: readonly string[] | undefined
    /** Optional request cancellation signal. */
    signal?: AbortSignal | undefined
    /** Exclusive ISO 8601 timestamp upper bound. */
    timestamp: string
  }
}

function createSendParam(options: createSendParam.Options): SendParam {
  const amount = BigInt(options.amount)
  return {
    amountLD: amount,
    composeMsg: '0x',
    dstEid: options.destinationEid,
    extraOptions: '0x',
    minAmountLD: BigInt(options.minimumAmount),
    oftCmd: '0x',
    to: recipientBytes32(options.recipientChainId, options.recipient),
  }
}

declare namespace createSendParam {
  type Options = {
    amount: string
    destinationEid: number
    minimumAmount: string
    recipient: string
    recipientChainId: string
  }
}

function isValidQuote(options: isValidQuote.Options) {
  const amount = BigInt(options.amount)
  const fees = options.feeDetails.reduce((total, fee) => total + fee.feeAmountLD, 0n)
  return (
    amount >= options.limit.minAmountLD &&
    amount <= options.limit.maxAmountLD &&
    options.receipt.amountSentLD === amount &&
    options.receipt.amountReceivedLD > 0n &&
    options.receipt.amountReceivedLD === amount + fees
  )
}

declare namespace isValidQuote {
  type Options = {
    amount: string
    feeDetails: readonly { feeAmountLD: bigint }[]
    limit: { maxAmountLD: bigint; minAmountLD: bigint }
    receipt: { amountReceivedLD: bigint; amountSentLD: bigint }
  }
}

function feeToken(sourceChainId: string) {
  if (sourceChainId === 'eip155:4217')
    return {
      address: Addresses.pathUsd,
      currency: 'USD',
      decimals: 6,
      name: 'pathUSD',
      standard: 'TIP-20',
      symbol: 'pathUSD',
      tokenKey: `${sourceChainId}/erc20:${Addresses.pathUsd.toLowerCase()}`,
      verified: true,
    }
  return {
    address: '0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee',
    currency: 'ETH',
    decimals: 18,
    name: 'Ether',
    standard: 'native',
    symbol: 'ETH',
    tokenKey: `${sourceChainId}/slip44:60`,
    verified: true,
  }
}

function quality() {
  return {
    liquiditySource: 'onchain',
    sourceDetail: 'stargate:oft-v2:taxi',
    tier: 'liquid' as const,
  }
}

function quoteRecipient() {
  return zeroAddress
}

function recipientBytes32(chainId: string, recipient: string) {
  if (chainId.startsWith('eip155:') && Address.validate(recipient, { strict: false }))
    return Hex.padLeft(recipient as Hex.Hex, 32)
  throw new RoutesProvider.ProviderConfigurationError()
}

function validRecipient(chainId: string, recipient: string) {
  try {
    recipientBytes32(chainId, recipient)
    return true
  } catch {
    return false
  }
}

function validateApproval(options: validateApproval.Options) {
  if (
    !Address.isEqual(options.call.to as Address.Address, options.token) ||
    BigInt(options.call.value) !== 0n
  )
    throw new RoutesProvider.ProviderPayloadError()
  const [spender, amount] = AbiFunction.decodeData(approve, options.call.data as Hex.Hex)
  if (!Address.isEqual(spender, options.spender) || amount !== options.amount)
    throw new RoutesProvider.ProviderPayloadError()
}

declare namespace validateApproval {
  type Options = {
    amount: bigint
    call: Action.Call
    spender: Address.Address
    token: Address.Address
  }
}

function validateSend(options: validateSend.Options) {
  const [sendParam, messagingFee, refundAddress] = AbiFunction.decodeData(send, options.data)
  const amount = BigInt(options.sourceAmount)
  if (
    !Address.isEqual(options.to, options.pool) ||
    sendParam.amountLD !== amount ||
    sendParam.composeMsg !== '0x' ||
    sendParam.dstEid !== options.destinationEid ||
    sendParam.extraOptions !== '0x' ||
    sendParam.minAmountLD !== BigInt(options.destinationAmountMin) ||
    sendParam.oftCmd !== '0x' ||
    !Hex.isEqual(sendParam.to, recipientBytes32(options.recipientChainId, options.recipient)) ||
    messagingFee.lzTokenFee !== 0n ||
    (options.nativeFee !== undefined && messagingFee.nativeFee !== options.nativeFee) ||
    !Address.isEqual(refundAddress, options.sender as Address.Address)
  )
    throw new RoutesProvider.ProviderPayloadError()
  return messagingFee
}

declare namespace validateSend {
  type Options = {
    data: Hex.Hex
    destinationAmountMin: string
    destinationEid: number
    nativeFee?: bigint | undefined
    pool: Address.Address
    recipient: string
    recipientChainId: string
    sender: string
    sourceAmount: string
    to: Address.Address
  }
}

function resolveDeployment(options: resolveDeployment.Options): Deployment | undefined {
  const parsed = schema.Configuration.safeParse(options.configuration)
  const source = deployments[options.sourceChainId as keyof typeof deployments]
  const destination = deployments[options.destinationChainId as keyof typeof deployments]
  const sourceEid = parsed.success && (parsed.data.sourceEid ?? source?.eid)
  if (
    !parsed.success ||
    !destination ||
    !source ||
    !sourceEid ||
    !options.sourceChainId.startsWith('eip155:') ||
    !('endpoint' in source) ||
    !matchesAsset(options.destinationChainId, options.destinationTokenAddress) ||
    !matchesAsset(options.sourceChainId, options.sourceTokenAddress) ||
    options.sourceChainId === options.destinationChainId
  )
    return undefined
  const destinationPoolAddress =
    parsed.data.destinationPoolAddress ??
    (options.destinationChainId === 'eip155:4217' ? defaultDestinationPool : undefined)
  return {
    ...(options.sourceChainId === 'eip155:4217'
      ? {
          alternateFee: {
            paymentToken: Address.checksum(Addresses.pathUsd),
            token: '0x0cEb237E109eE22374a567c6b09F373C73FA4cBb' as const,
          },
        }
      : {}),
    destinationEid: destination.eid,
    destinationPool: destinationPoolAddress ? Address.checksum(destinationPoolAddress) : undefined,
    pool: Address.checksum(parsed.data.poolAddress),
    sourceEid,
    sourceEndpoint: Address.checksum(source.endpoint),
    sourceToken: Address.checksum(options.sourceTokenAddress),
  }
}

function matchesAsset(chainId: string, address: string) {
  const asset = assets[chainId as keyof typeof assets]
  return (
    asset !== undefined &&
    Address.validate(address, { strict: false }) &&
    Address.isEqual(address as Address.Address, asset)
  )
}

declare namespace resolveDeployment {
  type Options = {
    configuration: unknown
    destinationChainId: string
    destinationTokenAddress: string
    sourceChainId: string
    sourceTokenAddress: string
  }
}

function unavailable(options: unavailable.Options) {
  return RoutesProvider.unavailableResult({
    detail: 'stargate:oft-v2',
    message: options.message,
    now: options.now,
    source: 'onchain',
  })
}

declare namespace unavailable {
  type Options = {
    message: string
    now: Date
  }
}