// deck.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors

// Assume data array is sorted by <accessor>
// Replaces the specified range with a new subarray
// Mutates the data array
// Returns {startRow, endRow} of the inserted items
export function replaceInRange({
  data,
  getIndex,
  dataRange,
  replace
}: {
  data: any[];
  getIndex: (d: any) => number;
  dataRange: {startRow?: number; endRow?: number};
  replace: any[];
}): {startRow: Number; endRow: number} {
  const {startRow = 0, endRow = Infinity} = dataRange;
  const count = data.length;
  let replaceStart = count;
  let replaceEnd = count;
  for (let i = 0; i < count; i++) {
    const row = getIndex(data[i]);
    if (replaceStart > i && row >= startRow) {
      replaceStart = i;
    }
    if (row >= endRow) {
      replaceEnd = i;
      break;
    }
  }
  let index = replaceStart;
  const dataLengthChanged = replaceEnd - replaceStart !== replace.length;
  // Save the items after replaceEnd before we overwrite data
  const endChunk = dataLengthChanged ? data.slice(replaceEnd) : undefined;
  // Insert new items
  for (let i = 0; i < replace.length; i++) {
    data[index++] = replace[i];
  }
  if (endChunk) {
    // Append items after replaceEnd
    for (let i = 0; i < endChunk.length; i++) {
      data[index++] = endChunk[i];
    }
    // Trim additional items
    data.length = index;
  }

  return {
    startRow: replaceStart,
    endRow: replaceStart + replace.length
  };
}