import * as ts from 'typescript'

import { Position } from './Position'

export class Range {
  constructor(
    public readonly start: Position,
    public readonly end: Position
  ) {}
  public compare(other: Range): number {
    const byStart = this.start.compare(other.start)
    if (byStart !== 0) {
      return byStart
    }
    return this.end.compare(other.end)
  }
  public toLsif(): number[] {
    if (this.isSingleLine()) {
      return [this.start.line, this.start.character, this.end.character]
    }
    return [
      this.start.line,
      this.start.character,
      this.end.line,
      this.end.character,
    ]
  }
  public static fromLsif(range: number[]): Range {
    const endLine = range.length === 3 ? range[0] : range[2]
    const endCharacter = range.length === 3 ? range[2] : range[3]
    return new Range(
      new Position(range[0], range[1]),
      new Position(endLine, endCharacter)
    )
  }
  public static fromNode(node: ts.Node): Range {
    const sourceFile = node.getSourceFile()
    const rangeNode: ts.Node = ts.isConstructorDeclaration(node)
      ? node.getFirstToken() ?? node
      : node
    const start = sourceFile.getLineAndCharacterOfPosition(rangeNode.getStart())
    const end = sourceFile.getLineAndCharacterOfPosition(rangeNode.getEnd())
    return new Range(
      new Position(start.line, start.character),
      new Position(end.line, end.character)
    )
  }
  public isSingleLine(): boolean {
    return this.start.line === this.end.line
  }
}