import { describe, expect, it } from 'vitest'
import { imageMarkdownSpansIn } from '@radial/core'
import { afterContainingImage, remap } from './insertion.js'

const URI = 'at://did:plc:abc/com.disnetdev.radial.image/3mrv'

describe('remap', () => {
  it('leaves a position before the edit where it was', () => {
    expect(remap('one two', 'one THREE two', 3)).toBe(3)
    expect(remap('one two', 'one THREE two', 0)).toBe(0)
  })

  it('moves a position after the edit by what the edit added or removed', () => {
    expect(remap('one two', 'one THREE two', 7)).toBe(13)
    expect(remap('one THREE two', 'one two', 13)).toBe(7)
  })

  it('associates forward, so text typed AT the point lands before it', () => {
    // This is the rule that makes a batch come out in order: the image this component just wrote
    // leaves the anchor after itself, ready for the next file of the same drop.
    expect(remap('ab', 'aXb', 1)).toBe(2)
    expect(remap('', `![one](radial-image:${URI})`, 0)).toBe(`![one](radial-image:${URI})`.length)
  })

  it('collapses a position inside deleted text to where the deletion ends', () => {
    expect(remap('a-DELETED-b', 'a-b', 6)).toBe(2)
  })

  it('lands at the end of a document the parent replaced wholesale', () => {
    // A composer clears its draft after a successful post. The upload still has to go somewhere, and
    // the end of what is there now is the only honest answer.
    expect(remap('a message', '', 4)).toBe(0)
    expect(remap('a message', 'a different draft', 4)).toBe('a different draft'.length)
  })

  it('takes a position outside the document and an unchanged one as they are', () => {
    expect(remap('abc', 'abc', 2)).toBe(2)
    expect(remap('abc', 'abcd', 99)).toBe(4)
    expect(remap('abc', 'abcd', -1)).toBe(0)
  })
})

describe('afterContainingImage', () => {
  const one = `![one](radial-image:${URI})`

  it('pushes a caret parked inside an image past the end of it', () => {
    // The editor selects the alt so the reader can correct it; typing over that selection leaves the
    // caret between `![` and `](`, which is the one place the next image must not go.
    expect(afterContainingImage(one, 3, 3)).toBe(one.length)
    expect(afterContainingImage(`tail ${one} more`, 8, 8)).toBe(5 + one.length)
  })

  it('leaves a caret at either edge of an image alone', () => {
    expect(afterContainingImage(one, 0, 0)).toBeUndefined()
    expect(afterContainingImage(one, one.length, one.length)).toBeUndefined()
  })

  it('leaves ordinary prose, and ordinary markdown images, alone', () => {
    expect(afterContainingImage('nothing here at all', 4, 4)).toBeUndefined()
    expect(afterContainingImage('![a cat](https://example.test/cat.png)', 4, 4)).toBeUndefined()
  })

  it('finds the image a selection runs into, whichever end is inside it', () => {
    expect(afterContainingImage(`${one} tail`, one.length - 2, one.length + 3)).toBe(one.length)
    expect(afterContainingImage(`tail ${one}`, 2, 8)).toBe(5 + one.length)
  })

  it('reports the second image when that is the one the caret is in', () => {
    const two = `![two](radial-image:${URI})`
    expect(afterContainingImage(one + two, one.length + 3, one.length + 3)).toBe(
      one.length + two.length,
    )
  })

  it('uses the core locator parser, including its case-insensitive scheme', () => {
    const mixed = `![one](RADIAL-IMAGE:${URI})`
    expect(imageMarkdownSpansIn(mixed)).toEqual([{ from: 0, to: mixed.length }])
    expect(afterContainingImage(mixed, 3, 3)).toBe(mixed.length)
    expect(imageMarkdownSpansIn('![one](radial-image:https://example.test/not-a-record)')).toEqual([])
  })
})