"use strict";

import { Logger } from "@ethersproject/logger";
import { version } from "./_version";
const logger = new Logger(version);

///////////////////////////////
// Exported Types

export type Bytes = ArrayLike<number>;

export type BytesLike = Bytes | string;

export type DataOptions = {
    allowMissingPrefix?: boolean;
    hexPad?: "left" | "right" | null;
};

export interface Hexable {
    toHexString(): string;
}


/*
export interface HexString {
    length: number;
    substring: (start: number, end?: number) => string;

    [index: number]: string;
}
*/

export type SignatureLike  = {
    r: string;
    s?: string;
    _vs?: string,
    recoveryParam?: number;
    v?: number;
} | BytesLike;

export interface Signature {
    r: string;

    s: string;
    _vs: string,

    recoveryParam: number;
    v: number;
}

///////////////////////////////


function isHexable(value: any): value is Hexable {
    return !!(value.toHexString);
}

function addSlice(array: Uint8Array): Uint8Array {
    if (array.slice) { return array; }

    array.slice = function() {
        const args = Array.prototype.slice.call(arguments);
        return addSlice(new Uint8Array(Array.prototype.slice.apply(array, args)));
    }

    return array;
}

export function isBytesLike(value: any): value is BytesLike {
    return ((isHexString(value) && !(value.length % 2)) || isBytes(value));
}

export function isBytes(value: any): value is Bytes {
    if (value == null) { return false; }

    if (value.constructor === Uint8Array) { return true; }
    if (typeof(value) === "string") { return false; }
    if (value.length == null) { return false; }

    for (let i = 0; i < value.length; i++) {
        const v = value[i];
        if (typeof(v) !== "number" || v < 0 || v >= 256 || (v % 1)) {
            return false;
        }
    }
    return true;
}


export function arrayify(value: BytesLike | Hexable | number, options?: DataOptions): Uint8Array {
    if (!options) { options = { }; }

    if (typeof(value) === "number") {
        logger.checkSafeUint53(value, "invalid arrayify value");

        const result = [];
        while (value) {
            result.unshift(value & 0xff);
            value = parseInt(String(value / 256));
        }
        if (result.length === 0) { result.push(0); }

        return addSlice(new Uint8Array(result));
    }

    if (options.allowMissingPrefix && typeof(value) === "string" && value.substring(0, 2) !== "0x") {
         value = "0x" + value;
    }

    if (isHexable(value)) { value = value.toHexString(); }

    if (isHexString(value)) {
        let hex = (<string>value).substring(2);
        if (hex.length % 2) {
            if (options.hexPad === "left") {
                hex = "0x0" + hex.substring(2);
            } else if (options.hexPad === "right") {
                hex += "0";
            } else {
                logger.throwArgumentError("hex data is odd-length", "value", value);
            }
        }

        const result = [];
        for (let i = 0; i < hex.length; i += 2) {
            result.push(parseInt(hex.substring(i, i + 2), 16));
        }

        return addSlice(new Uint8Array(result));
    }

    if (isBytes(value)) {
        return addSlice(new Uint8Array(value));
    }

    return logger.throwArgumentError("invalid arrayify value", "value", value);
}

export function concat(items: Array<BytesLike>): Uint8Array {
    const objects = items.map(item => arrayify(item));
    const length = objects.reduce((accum, item) => (accum + item.length), 0);

    const result = new Uint8Array(length);

    objects.reduce((offset, object) => {
        result.set(object, offset);
        return offset + object.length;
    }, 0);

    return addSlice(result);
}

export function stripZeros(value: BytesLike): Uint8Array {
    let result: Uint8Array = arrayify(value);

    if (result.length === 0) { return result; }

    // Find the first non-zero entry
    let start = 0;
    while (start < result.length && result[start] === 0) { start++ }

    // If we started with zeros, strip them
    if (start) {
        result = result.slice(start);
    }

    return result;
}

export function zeroPad(value: BytesLike, length: number): Uint8Array {
    value = arrayify(value);

    if (value.length > length) {
        logger.throwArgumentError("value out of range", "value", arguments[0]);
    }

    const result = new Uint8Array(length);
    result.set(value, length - value.length);
    return addSlice(result);
}


export function isHexString(value: any, length?: number): boolean {
    if (typeof(value) !== "string" || !value.match(/^0x[0-9A-Fa-f]*$/)) {
        return false
    }
    if (length && value.length !== 2 + 2 * length) { return false; }
    return true;
}

const HexCharacters: string = "0123456789abcdef";

export function hexlify(value: BytesLike | Hexable | number, options?: DataOptions): string {
    if (!options) { options = { }; }

    if (typeof(value) === "number") {
        logger.checkSafeUint53(value, "invalid hexlify value");

        let hex = "";
        while (value) {
            hex = HexCharacters[value & 0x0f] + hex;
            value = Math.floor(value / 16);
        }

        if (hex.length) {
            if (hex.length % 2) { hex = "0" + hex; }
            return "0x" + hex;
        }

        return "0x00";
    }

    if (options.allowMissingPrefix && typeof(value) === "string" && value.substring(0, 2) !== "0x") {
         value = "0x" + value;
    }

    if (isHexable(value)) { return value.toHexString(); }

    if (isHexString(value)) {
        if ((<string>value).length % 2) {
            if (options.hexPad === "left") {
                value = "0x0" + (<string>value).substring(2);
            } else if (options.hexPad === "right") {
                value += "0";
            } else {
                logger.throwArgumentError("hex data is odd-length", "value", value);
            }
        }
        return (<string>value).toLowerCase();
    }

    if (isBytes(value)) {
        let result = "0x";
        for (let i = 0; i < value.length; i++) {
             let v = value[i];
             result += HexCharacters[(v & 0xf0) >> 4] + HexCharacters[v & 0x0f];
        }
        return result;
    }

    return logger.throwArgumentError("invalid hexlify value", "value", value);
}

/*
function unoddify(value: BytesLike | Hexable | number): BytesLike | Hexable | number {
    if (typeof(value) === "string" && value.length % 2 && value.substring(0, 2) === "0x") {
        return "0x0" + value.substring(2);
    }
    return value;
}
*/
export function hexDataLength(data: BytesLike) {
    if (typeof(data) !== "string") {
        data = hexlify(data);
    } else if (!isHexString(data) || (data.length % 2)) {
        return null;
    }

    return (data.length - 2) / 2;
}

export function hexDataSlice(data: BytesLike, offset: number, endOffset?: number): string {
    if (typeof(data) !== "string") {
        data = hexlify(data);
    } else if (!isHexString(data) || (data.length % 2)) {
        logger.throwArgumentError("invalid hexData", "value", data );
    }

    offset = 2 + 2 * offset;

    if (endOffset != null) {
        return "0x" + data.substring(offset, 2 + 2 * endOffset);
    }

    return "0x" + data.substring(offset);
}

export function hexConcat(items: Array<BytesLike>): string {
    let result = "0x";
    items.forEach((item) => {
        result += hexlify(item).substring(2);
    });
    return result;
}

export function hexValue(value: BytesLike | Hexable | number): string {
    const trimmed = hexStripZeros(hexlify(value, { hexPad: "left" }));
    if (trimmed === "0x") { return "0x0"; }
    return trimmed;
}

export function hexStripZeros(value: BytesLike): string {
    if (typeof(value) !== "string") { value = hexlify(value); }

    if (!isHexString(value)) {
        logger.throwArgumentError("invalid hex string", "value", value);
    }
    value = value.substring(2);
    let offset = 0;
    while (offset < value.length && value[offset] === "0") { offset++; }
    return "0x" + value.substring(offset);
}

export function hexZeroPad(value: BytesLike, length: number): string {
    if (typeof(value) !== "string") {
        value = hexlify(value);
    } else if (!isHexString(value)) {
        logger.throwArgumentError("invalid hex string", "value", value);
    }

    if (value.length > 2 * length + 2) {
        logger.throwArgumentError("value out of range", "value", arguments[1]);
    }

    while (value.length < 2 * length + 2) {
        value = "0x0" + value.substring(2);
    }

    return value;
}

export function splitSignature(signature: SignatureLike): Signature {
    const result = {
        r: "0x",
        s: "0x",
        _vs: "0x",
        recoveryParam: 0,
        v: 0
    };

    if (isBytesLike(signature)) {
        const bytes: Uint8Array = arrayify(signature);
        if (bytes.length !== 65) {
            logger.throwArgumentError("invalid signature string; must be 65 bytes", "signature", signature);
        }

        // Get the r, s and v
        result.r = hexlify(bytes.slice(0, 32));
        result.s = hexlify(bytes.slice(32, 64));
        result.v = bytes[64];

        // Allow a recid to be used as the v
        if (result.v < 27) {
            if (result.v === 0 || result.v === 1) {
                result.v += 27;
            } else {
                logger.throwArgumentError("signature invalid v byte", "signature", signature);
            }
        }

        // Compute recoveryParam from v
        result.recoveryParam = 1 - (result.v % 2);

        // Compute _vs from recoveryParam and s
        if (result.recoveryParam) { bytes[32] |= 0x80; }
        result._vs = hexlify(bytes.slice(32, 64))

    } else {
        result.r = signature.r;
        result.s = signature.s;
        result.v = signature.v;
        result.recoveryParam = signature.recoveryParam;
        result._vs = signature._vs;

        // If the _vs is available, use it to populate missing s, v and recoveryParam
        // and verify non-missing s, v and recoveryParam
        if (result._vs != null) {
            const vs = zeroPad(arrayify(result._vs), 32);
            result._vs = hexlify(vs);

            // Set or check the recid
            const recoveryParam = ((vs[0] >= 128) ? 1: 0);
            if (result.recoveryParam == null) {
                result.recoveryParam = recoveryParam;
            } else if (result.recoveryParam !== recoveryParam) {
                logger.throwArgumentError("signature recoveryParam mismatch _vs", "signature", signature);
            }

            // Set or check the s
            vs[0] &= 0x7f;
            const s = hexlify(vs);
            if (result.s == null) {
                result.s = s;
            } else if (result.s !== s) {
                logger.throwArgumentError("signature v mismatch _vs", "signature", signature);
            }
        }

        // Use recid and v to populate each other
        if (result.recoveryParam == null) {
            if (result.v == null) {
                logger.throwArgumentError("signature missing v and recoveryParam", "signature", signature);
            } else if (result.v === 0 || result.v === 1) {
                result.recoveryParam = result.v;
            } else {
                result.recoveryParam = 1 - (result.v % 2);
            }
        } else {
            if (result.v == null) {
                result.v = 27 + result.recoveryParam;
            } else if (result.recoveryParam !== (1 - (result.v % 2))) {
                logger.throwArgumentError("signature recoveryParam mismatch v", "signature", signature);
            }
        }

        if (result.r == null || !isHexString(result.r)) {
            logger.throwArgumentError("signature missing or invalid r", "signature", signature);
        } else {
            result.r = hexZeroPad(result.r, 32);
        }

        if (result.s == null || !isHexString(result.s)) {
            logger.throwArgumentError("signature missing or invalid s", "signature", signature);
        } else {
            result.s = hexZeroPad(result.s, 32);
        }

        const vs = arrayify(result.s);
        if (vs[0] >= 128) {
            logger.throwArgumentError("signature s out of range", "signature", signature);
        }
        if (result.recoveryParam) { vs[0] |= 0x80; }
        const _vs = hexlify(vs);

        if (result._vs) {
            if (!isHexString(result._vs)) {
                logger.throwArgumentError("signature invalid _vs", "signature", signature);
            }
            result._vs = hexZeroPad(result._vs, 32);
        }

        // Set or check the _vs
        if (result._vs == null) {
            result._vs = _vs;
        } else if (result._vs !== _vs) {
            logger.throwArgumentError("signature _vs mismatch v and s", "signature", signature);
        }
    }

    return result;
}

export function joinSignature(signature: SignatureLike): string {
    signature = splitSignature(signature);

    return hexlify(concat([
         signature.r,
         signature.s,
         (signature.recoveryParam ? "0x1c": "0x1b")
    ]));
}