import * as Token from './Token.js'

/** Canonical identifier for a funding chain. */
export type Id = `eip155:${number}` | `solana:${string}` | `tron:${string}`

/** Chain metadata for a funding token. */
export type Chain = Callable &
  (
    | (Base & {
        /** Address encoding used by accounts and tokens on the chain. */
        addressFormat: 'hex'
        /** Chain execution family. */
        kind: 'evm'
      })
    | (Base & {
        /** Address encoding used by accounts and tokens on the chain. */
        addressFormat: 'base58'
        /** Chain execution family. */
        kind: 'solana'
      })
    | (Base & {
        /** Address encoding used by accounts and tokens on the chain. */
        addressFormat: 'base58check'
        /** Chain execution family. */
        kind: 'tron'
      })
  )

type Callable = (options: Callable.Options) => Selection

declare namespace Callable {
  /** Tokens selected for a funding route on this chain. */
  type Options = {
    /** Token definitions to resolve on the chain. */
    tokens: readonly Token.Token[]
  }
}

/** Tokens resolved for one funding chain. */
export type Selection = {
  /** Chain shared by every selected token. */
  chain: Chain
  /** Chain-scoped funding tokens. */
  tokens: readonly Token.Resolved[]
}

type Base = {
  /** Caller-facing aliases accepted for this chain. */
  aliases: readonly string[]
  /** CAIP-2 chain identifier. */
  id: Id
  /** Human-readable chain name. */
  name: string
  /** Parent chain identifier when this chain is a Zone. */
  parentChainId?: Id | undefined
  /** Public RPC endpoints used for funding-chain evidence. */
  rpcUrls: readonly string[]
  /** Stable chain segment used in quote identifiers. */
  slug: string
}

/** Creates funding chain metadata from a CAIP-2 identifier. */
export function from(options: from.Options): Chain {
  const { aliases = [], id, name, parentChainId, rpcUrls = [], slug } = options
  const base = { aliases, id, name, ...(parentChainId ? { parentChainId } : {}), rpcUrls, slug }
  const metadata = (() => {
    if (id.startsWith('eip155:')) return { ...base, addressFormat: 'hex', kind: 'evm' } as const
    if (id.startsWith('solana:'))
      return { ...base, addressFormat: 'base58', kind: 'solana' } as const
    if (id.startsWith('tron:'))
      return { ...base, addressFormat: 'base58check', kind: 'tron' } as const
    throw new InvalidIdError()
  })()
  function select(parameters: Callable.Options): Selection {
    const chain = select as Chain
    return {
      chain,
      tokens: parameters.tokens.map((token) => Token.resolve(token, chain)),
    }
  }
  return Object.defineProperties(
    select,
    Object.fromEntries(
      Object.entries(metadata).map(([key, value]) => [
        key,
        { configurable: true, enumerable: true, value },
      ]),
    ),
  ) as Chain
}

export declare namespace from {
  /** Funding chain definition. */
  type Options = {
    /** Additional caller-facing aliases accepted for this chain. */
    aliases?: readonly string[] | undefined
    /** CAIP-2 chain identifier. */
    id: Id
    /** Human-readable chain name. */
    name: string
    /** Parent chain identifier when this chain is a Zone. */
    parentChainId?: Id | undefined
    /** Public RPC endpoints used for funding-chain evidence. */
    rpcUrls?: readonly string[] | undefined
    /** Stable chain segment used in quote identifiers. */
    slug: string
  }
}

/** Returns the numeric portion of an EIP-155 CAIP-2 chain identifier. */
export function eip155Id(chain: Chain): string {
  const match = /^eip155:(\d+)$/.exec(chain.id)
  if (!match?.[1]) throw new InvalidIdError()
  return match[1]
}

/** Error thrown when a funding chain identifier is invalid for an operation. */
export class InvalidIdError extends Error {
  override name = 'Funding.Chain.InvalidIdError'
}