import { useMemo } from "react";
import { Interface } from "@ethersproject/abi";
import { ErrorDescription } from "@ethersproject/abi/lib/interface";
import useSWRImmutable from "swr/immutable";
import { ChecksummedAddress, TransactionData } from "../types";
import { useAppConfigContext } from "../useAppConfig";

export type UserMethod = {
  notice?: string | undefined;
};

export type UserEvent = {
  notice?: string | undefined;
};

export type UserError = [
  {
    notice?: string | undefined;
  }
];

export type UserDoc = {
  kind: "user";
  version?: number | undefined;
  notice?: string | undefined;
  methods: Record<string, UserMethod>;
  events: Record<string, UserEvent>;
  errors?: Record<string, UserError> | undefined;
};

export type DevMethod = {
  params?: Record<string, string>;
  returns?: Record<string, string>;
};

export type DevError = [
  {
    params?: Record<string, string>;
  }
];

export type DevDoc = {
  kind: "dev";
  version?: number | undefined;
  methods: Record<string, DevMethod>;
  errors?: Record<string, DevError> | undefined;
};

export type Metadata = {
  version: string;
  language: string;
  compiler: {
    version: string;
    keccak256?: string | undefined;
  };
  sources: {
    [filename: string]: {
      keccak256: string;
      content?: string | undefined;
      urls?: string[];
      license?: string;
    };
  };
  settings: {
    remappings: string[];
    optimizer?: {
      enabled: boolean;
      runs: number;
    };
    compilationTarget: {
      [filename: string]: string;
    };
    libraries: {
      [filename: string]: string;
    };
  };
  output: {
    abi: any[];
    userdoc?: UserDoc | undefined;
    devdoc?: DevDoc | undefined;
  };
};

export enum SourcifySource {
  // Resolve trusted IPNS for root IPFS
  IPFS_IPNS,

  // Centralized Sourcify servers
  CENTRAL_SERVER,
}

const sourcifyIPNS =
  "k51qzi5uqu5dll0ocge71eudqnrgnogmbr37gsgl12uubsinphjoknl6bbi41p";
const defaultIpfsGatewayPrefix = `https://ipfs.io/ipns/${sourcifyIPNS}`;
const sourcifyHttpRepoPrefix = `https://repo.sourcify.dev`;

const resolveSourcifySource = (source: SourcifySource) => {
  if (source === SourcifySource.IPFS_IPNS) {
    return defaultIpfsGatewayPrefix;
  }
  if (source === SourcifySource.CENTRAL_SERVER) {
    return sourcifyHttpRepoPrefix;
  }

  throw new Error(`Unknown Sourcify integration source code: ${source}`);
};

/**
 * Builds a complete Sourcify metadata.json URL given the contract address
 * and chain.
 */
export const sourcifyMetadata = (
  address: ChecksummedAddress,
  chainId: number,
  source: SourcifySource,
  type: MatchType
) =>
  `${resolveSourcifySource(source)}/contracts/${
    type === MatchType.FULL_MATCH ? "full_match" : "partial_match"
  }/${chainId}/${address}/metadata.json`;

export const sourcifySourceFile = (
  address: ChecksummedAddress,
  chainId: number,
  filepath: string,
  source: SourcifySource,
  type: MatchType
) =>
  `${resolveSourcifySource(source)}/contracts/${
    type === MatchType.FULL_MATCH ? "full_match" : "partial_match"
  }/${chainId}/${address}/sources/${filepath}`;

export enum MatchType {
  FULL_MATCH,
  PARTIAL_MATCH,
}

export type Match = {
  type: MatchType;
  metadata: Metadata;
};

const sourcifyFetcher = async (
  _: "sourcify",
  address: ChecksummedAddress,
  chainId: number,
  sourcifySource: SourcifySource
): Promise<Match | null | undefined> => {
  // Try full match
  try {
    const url = sourcifyMetadata(
      address,
      chainId,
      sourcifySource,
      MatchType.FULL_MATCH
    );
    const res = await fetch(url);
    if (res.ok) {
      return {
        type: MatchType.FULL_MATCH,
        metadata: await res.json(),
      };
    }
  } catch (err) {
    console.info(
      `error while getting Sourcify full_match metadata: chainId=${chainId} address=${address} err=${err}; falling back to partial_match`
    );
  }

  // Fallback to try partial match
  try {
    const url = sourcifyMetadata(
      address,
      chainId,
      sourcifySource,
      MatchType.PARTIAL_MATCH
    );
    const res = await fetch(url);
    if (res.ok) {
      return {
        type: MatchType.PARTIAL_MATCH,
        metadata: await res.json(),
      };
    }
    return null;
  } catch (err) {
    console.warn(
      `error while getting Sourcify partial_match metadata: chainId=${chainId} address=${address} err=${err}`
    );
    return null;
  }
};

export const useSourcifyMetadata = (
  address: ChecksummedAddress | undefined,
  chainId: number | undefined
): Match | null | undefined => {
  const { sourcifySource } = useAppConfigContext();
  const metadataURL = () =>
    address === undefined || chainId === undefined
      ? null
      : ["sourcify", address, chainId, sourcifySource];
  const { data, error } = useSWRImmutable<Match | null | undefined>(
    metadataURL,
    sourcifyFetcher
  );
  if (error) {
    return null;
  }
  return data;
};

const contractFetcher = async (url: string): Promise<string | null> => {
  const res = await fetch(url);
  if (res.ok) {
    return await res.text();
  }
  return null;
};

export const useContract = (
  checksummedAddress: string,
  networkId: number,
  filename: string,
  sourcifySource: SourcifySource,
  type: MatchType
) => {
  const normalizedFilename = filename.replaceAll(/[@:]/g, "_");
  const url = sourcifySourceFile(
    checksummedAddress,
    networkId,
    normalizedFilename,
    sourcifySource,
    type
  );

  const { data, error } = useSWRImmutable(url, contractFetcher);
  if (error) {
    return undefined;
  }
  return data;
};

export const useTransactionDescription = (
  metadata: Metadata | null | undefined,
  txData: TransactionData | null | undefined
) => {
  const txDesc = useMemo(() => {
    if (metadata === null) {
      return null;
    }
    if (!metadata || !txData) {
      return undefined;
    }

    const abi = metadata.output.abi;
    const intf = new Interface(abi as any);
    try {
      return intf.parseTransaction({
        data: txData.data,
        value: txData.value,
      });
    } catch (err) {
      console.warn("Couldn't find function signature", err);
      return null;
    }
  }, [metadata, txData]);

  return txDesc;
};

export const useError = (
  metadata: Metadata | null | undefined,
  output: string | null | undefined
): ErrorDescription | null | undefined => {
  const err = useMemo(() => {
    if (!metadata || !output) {
      return undefined;
    }

    const abi = metadata.output.abi;
    const intf = new Interface(abi as any);
    try {
      return intf.parseError(output);
    } catch (err) {
      console.warn("Couldn't find error signature", err);
      return null;
    }
  }, [metadata, output]);

  return err;
};