import { fromByteWidth, toByteWidth } from './bit-width-util.js';
import { BitWidth } from './bit-width.js';
import { fromUTF8Array, toUTF8Array } from './flexbuffers-util.js';
export function validateOffset(dataView, offset, width) {
    if (dataView.byteLength <= offset + width ||
        (offset & (toByteWidth(width) - 1)) !== 0) {
        throw 'Bad offset: ' + offset + ', width: ' + width;
    }
}
export function readInt(dataView, offset, width) {
    if (width < 2) {
        if (width < 1) {
            return dataView.getInt8(offset);
        }
        else {
            return dataView.getInt16(offset, true);
        }
    }
    else {
        if (width < 3) {
            return dataView.getInt32(offset, true);
        }
        else {
            if (dataView.setBigInt64 === undefined) {
                return (BigInt(dataView.getUint32(offset, true)) +
                    (BigInt(dataView.getUint32(offset + 4, true)) << BigInt(32)));
            }
            return dataView.getBigInt64(offset, true);
        }
    }
}
export function readUInt(dataView, offset, width) {
    if (width < 2) {
        if (width < 1) {
            return dataView.getUint8(offset);
        }
        else {
            return dataView.getUint16(offset, true);
        }
    }
    else {
        if (width < 3) {
            return dataView.getUint32(offset, true);
        }
        else {
            if (dataView.getBigUint64 === undefined) {
                return (BigInt(dataView.getUint32(offset, true)) +
                    (BigInt(dataView.getUint32(offset + 4, true)) << BigInt(32)));
            }
            return dataView.getBigUint64(offset, true);
        }
    }
}
export function readFloat(dataView, offset, width) {
    if (width < BitWidth.WIDTH32) {
        throw 'Bad width: ' + width;
    }
    if (width === BitWidth.WIDTH32) {
        return dataView.getFloat32(offset, true);
    }
    return dataView.getFloat64(offset, true);
}
export function indirect(dataView, offset, width) {
    const step = readUInt(dataView, offset, width);
    return offset - step;
}
export function keyIndex(key, dataView, offset, parentWidth, byteWidth, length) {
    const input = toUTF8Array(key);
    const keysVectorOffset = indirect(dataView, offset, parentWidth) - byteWidth * 3;
    const bitWidth = fromByteWidth(byteWidth);
    const indirectOffset = keysVectorOffset - Number(readUInt(dataView, keysVectorOffset, bitWidth));
    const _byteWidth = Number(readUInt(dataView, keysVectorOffset + byteWidth, bitWidth));
    let low = 0;
    let high = length - 1;
    while (low <= high) {
        const mid = (high + low) >> 1;
        const dif = diffKeys(input, mid, dataView, indirectOffset, _byteWidth);
        if (dif === 0)
            return mid;
        if (dif < 0) {
            high = mid - 1;
        }
        else {
            low = mid + 1;
        }
    }
    return null;
}
export function diffKeys(input, index, dataView, offset, width) {
    const keyOffset = offset + index * width;
    const keyIndirectOffset = keyOffset - Number(readUInt(dataView, keyOffset, fromByteWidth(width)));
    for (let i = 0; i < input.length; i++) {
        const dif = input[i] - dataView.getUint8(keyIndirectOffset + i);
        if (dif !== 0) {
            return dif;
        }
    }
    return dataView.getUint8(keyIndirectOffset + input.length) === 0 ? 0 : -1;
}
export function keyForIndex(index, dataView, offset, parentWidth, byteWidth) {
    const keysVectorOffset = indirect(dataView, offset, parentWidth) - byteWidth * 3;
    const bitWidth = fromByteWidth(byteWidth);
    const indirectOffset = keysVectorOffset - Number(readUInt(dataView, keysVectorOffset, bitWidth));
    const _byteWidth = Number(readUInt(dataView, keysVectorOffset + byteWidth, bitWidth));
    const keyOffset = indirectOffset + index * _byteWidth;
    const keyIndirectOffset = keyOffset -
        Number(readUInt(dataView, keyOffset, fromByteWidth(_byteWidth)));
    let length = 0;
    while (dataView.getUint8(keyIndirectOffset + length) !== 0) {
        length++;
    }
    return fromUTF8Array(new Uint8Array(dataView.buffer, keyIndirectOffset, length));
}
