// Select a seated CAD BIM subset for a batched export.
// The full 48k plan cannot be exported in one Blender pass, so batches are cut by tier and mask;
// every batch keeps the same schema so the exporter and verifier need no changes.
import { readFileSync, writeFileSync } from 'node:fs'

// Accept both `--key=value` and `--key value`; a bare `--key` means true.
const argv = process.argv.slice(2)
const args = {}
for (let i = 0; i < argv.length; i++) {
    if (!argv[i].startsWith('--')) continue
    const key = argv[i].slice(2)
    const eq = key.indexOf('=')
    if (eq >= 0) {
        args[key.slice(0, eq)] = key.slice(eq + 1)
    } else if (i + 1 < argv.length && !argv[i + 1].startsWith('--')) {
        args[key] = argv[++i]
    } else {
        args[key] = true
    }
}

const source = JSON.parse(readFileSync('tools/city-massing/city/cad-bim/seated-plan.json', 'utf8'))
let buildings = source.buildings
// `--exclude <manifest.json>` removes buildings already exported in an earlier batch, so
// successive batches tile the seated plan without duplication.
let excludedIds = new Set()
if (args.exclude) {
    for (const path of String(args.exclude).split(',')) {
        const manifest = JSON.parse(readFileSync(path, 'utf8'))
        for (const cell of manifest.cells) for (const id of cell.buildingIds) excludedIds.add(id)
    }
    buildings = buildings.filter((b) => !excludedIds.has(b.id))
}
if (args.tier) buildings = buildings.filter((b) => b.tier === args.tier)
if (args.mask) buildings = buildings.filter((b) => Number(b.maskId) === Number(args.mask))
if (args.max) {
    // Deterministic pick so a re-run selects the same buildings.
    const hash = (id) => {
        let value = 2166136261
        for (const ch of id) value = ((value ^ ch.charCodeAt(0)) * 16777619) >>> 0
        return value
    }
    buildings = [...buildings].sort((a, b) => hash(a.id) - hash(b.id)).slice(0, Number(args.max))
}
if (!buildings.length) throw new Error('selection is empty; check --tier/--mask/--max/--exclude')

const out = {
    ...source,
    buildings,
    batch: {
        tier: args.tier || 'all',
        mask: args.mask || 'all',
        selected: buildings.length,
        excludedByEarlierBatches: excludedIds.size,
        note: 'One batch of the seated CAD BIM plan for a bounded Blender export.',
    },
}
const outFile = args.out || 'tools/city-massing/city/cad-bim/seated-batch.json'
writeFileSync(outFile, JSON.stringify(out, null, 2))
console.log(JSON.stringify({
    out: outFile,
    selected: buildings.length,
    byKind: Object.fromEntries([...new Set(buildings.map((b) => b.kind))].map((k) => [k, buildings.filter((b) => b.kind === k).length])),
    byMask: Object.fromEntries([...new Set(buildings.map((b) => String(b.maskId)))].map((k) => [k, buildings.filter((b) => String(b.maskId) === k).length])),
}))