import { cfg }       from './config.mjs'
import { writeFile, readFile } from 'fs/promises'
import { existsSync } from 'fs'
import { resolve, dirname } from 'path'
import { fileURLToPath }    from 'url'

const DIR        = dirname(fileURLToPath(import.meta.url))
const SHAPES_PATH = resolve(DIR, 'public', 'aircraft.js')

export async function getShapes() {
	if (existsSync(SHAPES_PATH)) {
		return JSON.parse(await readFile(SHAPES_PATH, 'utf8'))
	}

	const r    = await fetch('https://raw.githubusercontent.com/wiedehopf/tar1090/refs/heads/master/html/markers.js')
	const text = await r.text()

	// Rip out just the `let shapes = { ... }` block by finding the matching closing brace
	const start = text.indexOf('let shapes = {')
	if (start === -1) throw new Error('Could not find shapes definition in markers.js')

	let depth = 0, end = -1
	for (let i = start + 'let shapes = '.length; i < text.length; i++) {
		if (text[i] === '{') depth++
		else if (text[i] === '}') { depth--; if (depth === 0) { end = i + 1; break } }
	}

	if (end === -1) throw new Error('Could not find end of shapes definition')

	// Use Function to eval the JS object safely (avoids JSON.parse issues with unquoted keys, comments etc)
	const shapes = new Function(`return ${text.slice(start + 'let shapes = '.length, end)}`)()

	await writeFile(SHAPES_PATH, JSON.stringify(shapes))
	return shapes
}

export async function getAirTraffic() {
	const { ADSB_URL } = cfg()
	if (!ADSB_URL) return { data: [] }
	const r = await fetch(`${ADSB_URL}/re-api/?all`)
	const j = await r.json()
	return { data: j.aircraft || [] }
}

export async function getAirTrafficHistory(icao) {
	const { ADSB_URL } = cfg()
	if (!ADSB_URL) return { history: [] }
	const r = await fetch(`${ADSB_URL}/re-api/?trace&icao=${icao}`)
	const j = await r.json()
	const history = (j.trace || []).map(t => ({
		latitude:  t[1],
		longitude: t[2],
		altitude:  t[3] || 0,
	}))
	return { history }
}