// node scripts/test-graphcols.mjs — the rule in src/graphcols.ts, on a curve scrolled one point at a time.
// (No test runner in this project: esbuild, which vite already brings, turns the one file into something node can load.)
import { buildSync } from 'esbuild'
import { pathToFileURL } from 'node:url'
import { mkdtempSync } from 'node:fs'
import { tmpdir } from 'node:os'
import { join } from 'node:path'

const out = join(mkdtempSync(join(tmpdir(), 'graphcols-')), 'graphcols.mjs')
buildSync({ entryPoints: [new URL('../src/graphcols.ts', import.meta.url).pathname], outfile: out, format: 'esm', logLevel: 'error' })
const { columnsOf, columnsAt } = await import(pathToFileURL(out).href)

const fails = []
const check = (ok, what, detail) => { if (!ok) fails.push(what + (detail !== undefined ? ' — ' + JSON.stringify(detail).slice(0, 200) : '')) }
const CAP = 300, COLS = 90 // the net graph: 300 points of history in about 90 dot-columns
const base = Array.from({ length: CAP }, (_, i) => (i === 100 ? 900 : i === 180 ? 500 : i === 251 ? 700 : 10))
const spikes = (cols) => cols.filter((v) => v > 100).sort((a, b) => b - a).join(',')

// what Top drew before 2026-09-21: the nearest point for each column, counted from the right edge
const nearest = (values, cap, cols) => { const n = Math.min(values.length, cap), seen = []; for (let c = 0; c < cols; c++) { const i = Math.floor((c * cap) / cols) - (cap - n); if (i >= 0) seen.push(values[values.length - n + i]) } return seen }

let values = base.slice(), advance = CAP - 1, prev = null
const oldShapes = new Set(), newShapes = new Set()
for (let step = 0; step < 40; step++) {
  oldShapes.add(spikes(nearest(values, CAP, COLS)))
  const cols = columnsOf(values, advance, CAP, COLS)
  newShapes.add(spikes(cols))
  if (prev) check([0, 1].some((sh) => cols.slice(0, -1).every((v, j) => prev[j + sh] === undefined || prev[j + sh] === v)), `frame ${step} is the one before, slid left by a column at most`)
  prev = cols
  values.push(10); values.shift(); advance++
}
check(oldShapes.size > 1, 'the test reproduces the fault it guards against (spikes flickering under nearest-point drawing)', [...oldShapes])
check(newShapes.size === 1 && [...newShapes][0] === '900,700,500', 'every spike is drawn, at its height, on every frame', [...newShapes])
check(columnsOf(base, CAP - 1, CAP, COLS).length === COLS, 'a full curve fills the box')
const young = columnsOf(base.slice(-30), 29, CAP, COLS).length
check(young >= 8 && young <= 10, 'a tenth of a history takes a tenth of the box, from the right', young)
const wide = columnsOf(base, CAP - 1, CAP, 390)
check(wide.length === 390 && Math.max(...wide) === 900, 'a box wider than the history is filled, nothing invented', wide.length)
check(columnsOf([], 0, CAP, COLS).length === 0 && columnsOf([5], 0, 2, 50).length >= 1, 'empty and single-point curves')

// Sliding with the ticks: four ticks to a point (a 250 ms rate, a 1 s stride). Every tick moves
// the graph left by the same fraction of a column, the newest column grows in from the right, and
// a column, once finished, keeps its value wherever it has slid to.
for (const cols of [COLS, 390]) {
  let v = base.slice(), adv = CAP - 1, prevAt = null, back = 0, jump = 0, held = 0
  const was = new Map() // a finished column's value, by its number
  for (let t = 0; t < 4 * 30; t++) {
    const now = adv + ((t % 4) + 1) / 4
    const { cols: seen, edge, last } = columnsAt(v, adv, now, CAP, cols)
    check(edge > 0 && edge <= 1, `edge in (0, 1] (${cols} cols)`, edge)
    check(seen.length >= cols - 2 && seen.length <= cols + 1, `the box is filled, give or take the sliver (${cols} cols)`, seen.length)
    const at = last + edge // how far the graph has slid, in columns
    if (prevAt !== null) { if (at < prevAt - 1e-9) back++; if (at > prevAt + 1 + 1e-9) jump++; if (Math.abs(at - prevAt) < 1e-9) held++ }
    prevAt = at
    seen.forEach((x, i) => { const k = last - (seen.length - 1 - i); if (k < last - 1) { if (was.has(k) && was.get(k) !== x) fails.push(`column ${k} changed after it was finished`); was.set(k, x) } })
    if ((t % 4) === 3) { v.push(10); v.shift(); adv++ }
  }
  check(back === 0 && jump === 0, `the graph only slides left, less than a column a tick (${cols} cols)`, { back, jump })
  check(held < 4 * 30 / 4, `the graph moves on almost every tick, not once a point (${cols} cols)`, held)
}
// a point per tick (stride == rate) is the old layout exactly
check(JSON.stringify(columnsAt(base, CAP - 1, CAP, CAP, COLS).cols.slice(-COLS)) === JSON.stringify(columnsOf(base, CAP - 1, CAP, COLS)), 'columnsOf is columnsAt at a whole point')

if (fails.length) { console.error('graphcols: FAIL\n  ' + fails.join('\n  ')); process.exit(1) }
console.log('graphcols: ok')