function processLineWithColon()

in src/yaml/yamlUtils.ts [127:247]
81 lines of code
11 McCabe index (conditional complexity)

function processLineWithColon(
  document: TextDocument,
  cursorPosition: Position,
  currentLine: string,
  currentLineEnd: number,
): ProcessYamlDocForCompletionOutput {
  const docText = document.getText()
  const docTextLength = docText.length

  let modifiedDocText: string = docText
  let shouldPrependSpace = false

  const tempPositionForCompletions: Position = { ...cursorPosition }
  const startPositionForInsertion: Position = { ...cursorPosition }
  const endPositionForInsertion: Position = { ...cursorPosition }

  const charNum = cursorPosition.character
  const lineOffsets = getLineOffsets(docText)

  let preText: string
  let postText: string
  let insertedText: string

  // Current line has a colon, determine if cursor position is right or left of it
  const colonIndex = currentLine.indexOf(':')

  // Cursor is left of the colon.
  if (charNum <= colonIndex) {
    // Start position is first non-space character, ending position is left of colon.
    const preColonTextTrimmed = currentLine.substring(0, colonIndex).trim()

    // Only whitespace before the colon.
    if (preColonTextTrimmed.length === 0) {
      // Insert placeholder quotes and place cursor inside of them.
      preText = docText.substring(0, lineOffsets[cursorPosition.line] + colonIndex)
      insertedText = "''"
      postText = docText.slice(lineOffsets[cursorPosition.line] + colonIndex)

      startPositionForInsertion.character = colonIndex
      endPositionForInsertion.character = colonIndex
      tempPositionForCompletions.character = colonIndex + 1

      // Only hyphen before the colon.
    } else if (preColonTextTrimmed.length === 1 && preColonTextTrimmed.charAt(0) === '-') {
      // Insert placeholder quotes and place cursor inside of them.
      preText = docText.substring(0, lineOffsets[cursorPosition.line] + colonIndex)
      insertedText = " ''"
      postText = docText.slice(lineOffsets[cursorPosition.line] + colonIndex)

      startPositionForInsertion.character = colonIndex
      endPositionForInsertion.character = colonIndex

      // Move cursor to be inside the quotes
      tempPositionForCompletions.character = colonIndex + 2
      shouldPrependSpace = currentLine.charAt(Math.max(colonIndex - 1, 0)) !== ' '
    } else {
      // Set start of insertion range to be where the non-whitespace characters start.
      startPositionForInsertion.character = currentLine.indexOf(preColonTextTrimmed)
      // Set end of insertion range to be immediately before the colon.
      endPositionForInsertion.character = colonIndex

      preText = docText
      insertedText = ''
      postText = ''

      // If the non-whitespace characters start with a hyphen, adjust starting position to be after the hyphen
      if (preColonTextTrimmed.charAt(0) === '-') {
        startPositionForInsertion.character = Math.min(startPositionForInsertion.character + 2, colonIndex)
      }
    }

    // Cursor is right of the colon.
  } else {
    // Starting position is immediately after the colon, end is end of line
    startPositionForInsertion.character = colonIndex + 1
    endPositionForInsertion.character = currentLine.length
    shouldPrependSpace = true

    // Remove all trailing whitespace on that line and adjust tempPositionForCompletions if needed
    let numTrailingSpacesToRemove = 0
    while (currentLine.charAt(currentLine.length - numTrailingSpacesToRemove - 1) === ' ') {
      numTrailingSpacesToRemove++
    }
    tempPositionForCompletions.character = Math.min(
      tempPositionForCompletions.character,
      currentLine.length - numTrailingSpacesToRemove - 1,
    )

    // If after removing trailing spaces, the last character is the colon, add a placeholder empty string value
    const postColonTextTrimmed = currentLine.substring(colonIndex + 1).trim()
    const hasOnlyWhitespaceAfterColon = postColonTextTrimmed.length === 0

    preText = docText.substring(0, currentLineEnd - numTrailingSpacesToRemove)
    insertedText = (hasOnlyWhitespaceAfterColon ? ' ""' : '') + '\n'
    postText = docText.slice(lineOffsets[cursorPosition.line + 1] || docTextLength)

    if (hasOnlyWhitespaceAfterColon) {
      // Move cursor inside of quotes
      tempPositionForCompletions.character += 2
    } else {
      // Current line has non-whitespace characters following the colon.
      const indexOfPostColonCharacters = currentLine.indexOf(postColonTextTrimmed)

      // Cursor is between colon and start of post-colon characters
      if (charNum < indexOfPostColonCharacters) {
        // Move cursor to be at immediately before the value
        tempPositionForCompletions.character = indexOfPostColonCharacters
      }
    }
  }

  modifiedDocText = `${preText}${insertedText}${postText}`

  return {
    modifiedDocText,
    tempPositionForCompletions,
    startPositionForInsertion,
    endPositionForInsertion,
    shouldPrependSpace,
  }
}