import {Options, Value} from './tstype';
import {IsNumberArray} from '../utils';

class Buffalo {
    protected position: number;
    protected buffer: Buffer;

    public constructor(buffer: Buffer, position = 0) {
        this.position = position;
        this.buffer = buffer;
    }

    public getPosition(): number {
        return this.position;
    }

    public getBuffer(): Buffer {
        return this.buffer;
    }

    public readEmpty(): Value {
        return null;
    }

    public writeEmpty(): void {
    }

    public writeInt8(value: number): void {
        this.buffer.writeInt8(value, this.position);
        this.position++;
    }

    public readInt8(): Value {
        const value = this.buffer.readInt8(this.position);
        this.position++;
        return value;
    }

    public writeUInt8(value: number): void {
        this.buffer.writeUInt8(value, this.position);
        this.position++;
    }

    public readUInt8(): Value {
        const value = this.buffer.readUInt8(this.position);
        this.position++;
        return value;
    }

    public writeUInt16(value: number): void {
        this.buffer.writeUInt16LE(value, this.position);
        this.position += 2;
    }

    public readUInt24(): Value {
        const lsb = this.readUInt16();
        const msb = this.readUInt8();
        return (msb * 65536) + lsb;
    }

    public writeUInt24(value: number): void {
        let temp = Buffer.alloc(4);
        temp.writeUInt32LE(value, 0);
        temp = temp.slice(0, 3);
        this.writeBuffer(temp, 3);
    }

    public readInt24(): Value {
        const lsb = this.readUInt16();
        const msb = this.readUInt8();
        const sign = (msb & 0x80) >> 7;
        let value = ((msb & 0x7F) * 65536) + lsb;

        if (sign) {
            value = -(0x7FFFFF - value + 1);
        }

        return value;
    }

    public writeInt24(value: number): void {
        let temp = Buffer.alloc(4);
        temp.writeInt32LE(value, 0);
        temp = temp.slice(0, 3);
        this.writeBuffer(temp, 3);
    }

    public readUInt16(): Value {
        const value = this.buffer.readUInt16LE(this.position);
        this.position += 2;
        return value;
    }

    public writeInt16(value: number): void {
        this.buffer.writeInt16LE(value, this.position);
        this.position += 2;
    }

    public readInt16(): Value {
        const value = this.buffer.readInt16LE(this.position);
        this.position += 2;
        return value;
    }

    public writeUInt32(value: number): void {
        this.buffer.writeUInt32LE(value, this.position);
        this.position += 4;
    }

    public readUInt32(): Value {
        const value = this.buffer.readUInt32LE(this.position);
        this.position += 4;
        return value;
    }

    public writeInt32(value: number): void {
        this.buffer.writeInt32LE(value, this.position);
        this.position += 4;
    }

    public readInt32(): Value {
        const value = this.buffer.readInt32LE(this.position);
        this.position += 4;
        return value;
    }

    public writeFloatLE(value: number): void {
        this.buffer.writeFloatLE(value, this.position);
        this.position += 4;
    }

    public readFloatLE(): Value {
        const value = this.buffer.readFloatLE(this.position);
        this.position += 4;
        return value;
    }

    public writeDoubleLE(value: number): void {
        this.buffer.writeDoubleLE(value, this.position);
        this.position += 8;
    }

    public readDoubleLE(): Value {
        const value = this.buffer.readDoubleLE(this.position);
        this.position += 8;
        return value;
    }

    public writeIeeeAddr(value: string): void {
        this.writeUInt32(parseInt(value.slice(10), 16));
        this.writeUInt32(parseInt(value.slice(2, 10), 16));
    }

    public readIeeeAddr(): Value {
        const length = 8;
        const value = this.buffer.slice(this.position, this.position + length);
        this.position += length;
        return Buffalo.addressBufferToString(value);
    }

    private static addressBufferToString(buffer: Buffer): string {
        let address = '0x';
        for (let i = 0; i < buffer.length; i++) {
            const value = buffer.readUInt8(buffer.length - i - 1);
            if (value <= 15) {
                address += '0' + value.toString(16);
            } else {
                address += value.toString(16);
            }
        }

        return address;
    }

    protected readBuffer(length: number): Value {
        const value = this.buffer.slice(this.position, this.position + length);
        this.position += length;
        return value;
    }

    protected writeBuffer(values: Buffer | number[], length: number): void {
        if (values.length !== length) {
            throw new Error(`Length of values: '${values}' is not consitent with expected length '${length}'`);
        }

        for (const value of values) {
            this.writeUInt8(value);
        }
    }

    public writeListUInt8(values: number[]): void {
        for (const value of values) {
            this.writeUInt8(value);
        }
    }

    public readListUInt8(options: Options): Value {
        const value = [];
        for (let i = 0; i < options.length; i++) {
            value.push(this.readUInt8());
        }

        return value;
    }

    public writeListUInt16(values: number[]): void {
        for (const value of values) {
            this.writeUInt16(value);
        }
    }

    public readListUInt16(options: Options): Value {
        const value = [];
        for (let i = 0; i < options.length; i++) {
            value.push(this.readUInt16());
        }

        return value;
    }

    public writeListUInt24(values: number[]): void {
        for (const value of values) {
            this.writeUInt24(value);
        }
    }

    public readListUInt24(options: Options): Value {
        const value = [];
        for (let i = 0; i < options.length; i++) {
            value.push(this.readUInt24());
        }

        return value;
    }

    public writeListUInt32(values: number[]): void {
        for (const value of values) {
            this.writeUInt32(value);
        }
    }

    public readListUInt32(options: Options): Value {
        const value = [];
        for (let i = 0; i < options.length; i++) {
            value.push(this.readUInt32());
        }

        return value;
    }

    public write(type: string, value: Value, options: Options): void {
        options; // prevent not used eslint warning

        if (type === 'UINT8') {
            this.writeUInt8(value);
        } else if (type === 'UINT16') {
            this.writeUInt16(value);
        } else if (type === 'UINT32') {
            this.writeUInt32(value);
        }  else if (type === 'IEEEADDR') {
            this.writeIeeeAddr(value);
        } else if (type.startsWith('BUFFER') && (Buffer.isBuffer(value) || IsNumberArray(value))) {
            let length = Number(type.replace('BUFFER', ''));
            length = length != 0 ? length : value.length;
            this.writeBuffer(value, length);
        } else if (type === 'INT8') {
            this.writeInt8(value);
        } else if (type === 'INT16') {
            this.writeInt16(value);
        } else if (type === 'UINT24') {
            this.writeUInt24(value);
        } else if (type === 'INT24') {
            this.writeInt24(value);
        } else if (type === 'INT32') {
            this.writeInt32(value);
        } else if (type === 'FLOATLE') {
            this.writeFloatLE(value);
        } else if (type === 'DOUBLELE') {
            this.writeDoubleLE(value);
        } else if (type === 'EMPTY') {
            this.writeEmpty();
        } else if (type === 'LIST_UINT8') {
            this.writeListUInt8(value);
        } else if (type === 'LIST_UINT16') {
            this.writeListUInt16(value);
        } else if (type === 'LIST_UINT24') {
            this.writeListUInt24(value);
        } else if (type === 'LIST_UINT32') {
            this.writeListUInt32(value);
        } else {
            throw new Error(`Write for '${type}' not available`);
        }
    }

    public read(type: string, options: Options): Value {
        if (type === 'UINT8') {
            return this.readUInt8();
        } else if (type === 'UINT16') {
            return this.readUInt16();
        } else if (type === 'UINT32') {
            return this.readUInt32();
        }  else if (type === 'IEEEADDR') {
            return this.readIeeeAddr();
        } else if (type.startsWith('BUFFER')) {
            let length = Number(type.replace('BUFFER', ''));
            length = length != 0 ? length : options.length;
            return this.readBuffer(length);
        } else if (type === 'INT8') {
            return this.readInt8();
        } else if (type === 'INT16') {
            return this.readInt16();
        } else if (type === 'UINT24') {
            return this.readUInt24();
        } else if (type === 'INT24') {
            return this.readInt24();
        } else if (type === 'INT32') {
            return this.readInt32();
        } else if (type === 'FLOATLE') {
            return this.readFloatLE();
        } else if (type === 'DOUBLELE') {
            return this.readDoubleLE();
        } else if (type === 'EMPTY') {
            return this.readEmpty();
        } else if (type === 'LIST_UINT8') {
            return this.readListUInt8(options);
        } else if (type === 'LIST_UINT16') {
            return this.readListUInt16(options);
        } else if (type === 'LIST_UINT24') {
            return this.readListUInt24(options);
        } else if (type === 'LIST_UINT32') {
            return this.readListUInt32(options);
        } else {
            throw new Error(`Read for '${type}' not available`);
        }
    }
}



export default Buffalo;