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 { sourcifyMetadata, SourcifySource, sourcifySourceFile } from "../url";
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;
  };
};

const sourcifyFetcher = async (url: string) => {
  try {
    const res = await fetch(url);
    if (res.ok) {
      return res.json();
    }
    return null;
  } catch (err) {
    console.warn(
      `error while getting Sourcify metadata: url=${url} err=${err}`
    );
    return null;
  }
};

export const useSourcifyMetadata = (
  address: ChecksummedAddress | undefined,
  chainId: number | undefined
): Metadata | null | undefined => {
  const { sourcifySource } = useAppConfigContext();
  const metadataURL = () =>
    address === undefined || chainId === undefined
      ? null
      : sourcifyMetadata(address, chainId, sourcifySource);
  const { data, error } = useSWRImmutable<Metadata>(
    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
) => {
  const normalizedFilename = filename.replaceAll(/[@:]/g, "_");
  const url = sourcifySourceFile(
    checksummedAddress,
    networkId,
    normalizedFilename,
    sourcifySource
  );

  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;
};