#!/usr/bin/env node
//
// Build the committed spawn atlas artifact from a ServUO tree.
//
//   npm run atlas:build -- --servuo C:\path\to\ServUO [--out db/data]
//
// This is the ONLY thing in the repo that reads a ServUO tree, and it is
// CLI-only by design: the website container has no ServUO tree, and pushing
// 10.5 MB of XML through a parser on every boot to produce data that changes
// when an operator edits their spawns — that is, almost never — would be pure
// waste. The build runs on a machine that has the tree, its output is committed,
// and `atlas:import` (which needs no tree) loads it into the database.
//
// All parsing lives in `src/utils/spawnAtlasParse.js` as pure functions so it
// is unit-tested in CI without a ServUO tree. This file is the fs/CLI shell
// around it: read, transform, shard, write.
//
// It writes NO images. Creature art is deliberately not part of the artifact —
// sprites live in the operator's own client files (`.mul`/`.uop`) and are theirs
// to extract and supply. See `db/data/spawnAtlas.art.example.json` and
// docs/website/SPAWN_ATLAS.md for that path; `art` stays NULL without it.

const crypto = require('crypto')
const fs = require('fs')
const path = require('path')

const {
  parsePoints,
  parseRegions,
  parseLocations,
  parseChampions,
  buildPlacementIndex,
  resolveRegion,
  normalizeFacet,
  slugify,
} = require('../src/utils/spawnAtlasParse')

const ARTIFACT_VERSION = 1

// ── CLI ────────────────────────────────────────────────────────────────────

function parseArgs(argv) {
  const args = { servuo: '', out: path.join(__dirname, '..', 'db', 'data'), radius: undefined }
  for (let i = 0; i < argv.length; i += 1) {
    const flag = argv[i]
    if (flag === '--servuo') args.servuo = argv[++i]
    else if (flag === '--out') args.out = argv[++i]
    else if (flag === '--landmark-radius') args.radius = Number(argv[++i])
    else if (flag === '--help' || flag === '-h') args.help = true
  }
  return args
}

const USAGE = `
Build the spawn atlas artifact from a ServUO tree.

  node scripts/buildSpawnAtlas.js --servuo <path> [--out <dir>] [--landmark-radius <tiles>]

  --servuo           Path to the ServUO server root (the directory holding
                     Spawns/, Data/ and Config/). Required.
  --out              Output directory. Default: server/db/data
  --landmark-radius  Max tile distance for the landmark fallback. Default: 200

Writes spawnAtlas.index.json plus one spawnAtlas.<facet>.json per facet.
Commit the result; load it with "npm run atlas:import".
`

// ── Source files ───────────────────────────────────────────────────────────

function readIfPresent(file) {
  try {
    return fs.readFileSync(file, 'utf8')
  } catch (err) {
    if (err.code === 'ENOENT') return null
    throw err
  }
}

function sha256(text) {
  return crypto.createHash('sha256').update(text, 'utf8').digest('hex')
}

function listXml(dir) {
  try {
    return fs
      .readdirSync(dir)
      .filter((name) => name.toLowerCase().endsWith('.xml'))
      .sort()
  } catch (err) {
    if (err.code === 'ENOENT') return []
    throw err
  }
}

// ── Transform ──────────────────────────────────────────────────────────────

/**
 * Roll spawn points up into per-type creature rows.
 *
 * `total` is the sum of each type's own MX across every point that spawns it —
 * i.e. how many of this creature the world holds at once, which is the number
 * worth showing. `facets` is a per-facet point count, used both for the facet
 * filter and to answer "where does this live" without loading its points.
 */
function aggregateCreatures(points) {
  const creatures = new Map()
  for (const point of points) {
    for (const entry of point.types) {
      const slug = slugify(entry.type)
      if (slug === '') continue
      let creature = creatures.get(slug)
      if (!creature) {
        creature = { slug, name: '', total: 0, points: 0, facets: {}, spellings: new Map() }
        creatures.set(slug, creature)
      }
      creature.total += entry.max
      creature.points += 1
      creature.facets[point.facet] = (creature.facets[point.facet] || 0) + 1
      creature.spellings.set(entry.type, (creature.spellings.get(entry.type) || 0) + 1)
    }
  }

  return [...creatures.values()]
    .map(({ spellings, ...creature }) => ({
      ...creature,
      name: displayName(spellings),
    }))
    .sort((a, b) => a.slug.localeCompare(b.slug))
}

/**
 * Choose one display spelling for a creature.
 *
 * The shard's spawn files are not consistent about case — the same creature is
 * written `Lizardman` in one file and `lizardman` in another. Slugging collapses
 * them into one creature correctly, but the display name then depended on
 * whichever file happened to be read first, which is exactly the kind of thing
 * that produces a spurious diff in a committed artifact on an unrelated rebuild.
 *
 * So: most frequent spelling wins; ties break toward the one with more
 * capitals (`Lizardman` over `lizardman`), then alphabetically. Fully
 * deterministic, and independent of file read order.
 */
function displayName(spellings) {
  const capitals = (value) => (value.match(/[A-Z]/g) || []).length
  return [...spellings.entries()].sort((a, b) => {
    if (b[1] !== a[1]) return b[1] - a[1]
    const caps = capitals(b[0]) - capitals(a[0])
    if (caps !== 0) return caps
    return a[0].localeCompare(b[0])
  })[0][0]
}

function build(args) {
  const root = args.servuo
  if (!fs.existsSync(root)) {
    throw new Error(`ServUO path does not exist: ${root}`)
  }

  const source = {}
  const record = (label, file, text) => {
    source[label] = { bytes: Buffer.byteLength(text, 'utf8'), sha256: sha256(text) }
    return text
  }

  // Regions + landmarks first — the placement index needs both before any
  // point can be resolved.
  const regionsPath = path.join(root, 'Data', 'Regions.xml')
  const regionsXml = readIfPresent(regionsPath)
  if (regionsXml === null) throw new Error(`Missing required file: ${regionsPath}`)
  const regions = parseRegions(record('Data/Regions.xml', regionsPath, regionsXml))

  const locationsDir = path.join(root, 'Data', 'Locations')
  const landmarks = []
  for (const name of listXml(locationsDir)) {
    const file = path.join(locationsDir, name)
    const xml = record(`Data/Locations/${name}`, file, fs.readFileSync(file, 'utf8'))
    landmarks.push(...parseLocations(xml, path.basename(name, '.xml')))
  }

  const index = buildPlacementIndex(regions, landmarks)
  const resolveOpts = args.radius ? { landmarkRadius: args.radius } : {}

  // Spawn points. There are 13 files but only 6 facets — the facet comes from
  // each record's <Map>, so sharding is driven by the data, not the file names.
  const spawnsDir = path.join(root, 'Spawns')
  const spawnFiles = listXml(spawnsDir)
  if (spawnFiles.length === 0) throw new Error(`No spawn files found in ${spawnsDir}`)

  const rawPoints = []
  for (const name of spawnFiles) {
    const file = path.join(spawnsDir, name)
    const xml = record(`Spawns/${name}`, file, fs.readFileSync(file, 'utf8'))
    rawPoints.push(...parsePoints(xml))
  }

  // A spawner switched off in-world produces nothing; advertising it would be a
  // straight lie to a player planning a hunt.
  const disabled = rawPoints.filter((point) => !point.running).length
  const points = rawPoints
    .filter((point) => point.running)
    // A spawner with no types is a placeholder — it has nothing to show.
    .filter((point) => point.types.length > 0)
    .map((point) => {
      const placement = resolveRegion(point.x, point.y, point.facet, index, resolveOpts)
      // The full, honest shape. Compaction happens once, in encodePoint(), at
      // write time — so everything in between (aggregateCreatures, the facet
      // grouping, the counts) works on real fields rather than on holes.
      return {
        name: point.name,
        facet: point.facet,
        x: point.x,
        y: point.y,
        width: point.width,
        height: point.height,
        range: point.range,
        maxCount: point.maxCount,
        minDelay: point.minDelay,
        maxDelay: point.maxDelay,
        todStart: point.todStart,
        todEnd: point.todEnd,
        todMode: point.todMode,
        region: placement.region,
        landmark: placement.landmark,
        types: point.types,
      }
    })

  // Champions are configured altars, not the live champ.update feed. Resolving
  // them through the same index means "Deceit" reads consistently on both.
  const championsPath = path.join(root, 'Config', 'ChampionSpawns.xml')
  const championsXml = readIfPresent(championsPath)
  const champions = (
    championsXml === null
      ? []
      : parseChampions(record('Config/ChampionSpawns.xml', championsPath, championsXml))
  ).map((champ) => ({
    ...champ,
    slug: slugify(`${champ.facet}-${champ.name}`),
    label: resolveRegion(champ.x, champ.y, champ.facet, index, resolveOpts).label,
  }))

  const creatures = aggregateCreatures(points)
  const facets = [...new Set(points.map((point) => point.facet))].sort()

  const unresolved = points.filter((point) => !point.region && !point.landmark).length
  const meta = {
    version: ARTIFACT_VERSION,
    generatedAt: new Date().toISOString(),
    landmarkRadius: args.radius ?? undefined,
    counts: {
      facets: facets.length,
      points: points.length,
      pointsDisabled: disabled,
      creatures: creatures.length,
      regions: regions.length,
      landmarks: landmarks.length,
      champions: champions.length,
      unresolvedPoints: unresolved,
    },
    source,
  }

  return { meta, facets, creatures, regions, landmarks, champions, points }
}

// ── Write ──────────────────────────────────────────────────────────────────

/**
 * Encode one point for the artifact. The whole compaction scheme lives here, so
 * this function and `readPoint()` in importSpawnAtlas.js are exact inverses;
 * test/spawnAtlas.build.test.js round-trips the pair. Change one, change both.
 *
 * Three space savings, worth ~3 MB across the world:
 *
 *   - `facet` is dropped. The shard file names its facet once at the top rather
 *     than repeating it on all ~2,500 of its records.
 *   - Fields at their default are omitted rather than written as 0. Most
 *     spawners are a single point with no time-of-day gating, so `width`,
 *     `height`, `range` and the three `tod*` fields are zero on the large
 *     majority of records.
 *   - `types` becomes [name, max] tuples. There are ~24,000 type entries across
 *     the world, and `{"type":"Orc","max":1}` spends 15 bytes apiece restating
 *     two key names that never vary.
 *
 * `label` is not written at all: it is exactly `region || landmark ||
 * "Wilderness"`, and the importer recomputes it.
 */
function encodePoint(point) {
  const out = {
    name: point.name,
    x: point.x,
    y: point.y,
    maxCount: point.maxCount,
    types: point.types.map((entry) => [entry.type, entry.max]),
  }
  if (point.width) out.width = point.width
  if (point.height) out.height = point.height
  if (point.range) out.range = point.range
  if (point.minDelay) out.minDelay = point.minDelay
  if (point.maxDelay) out.maxDelay = point.maxDelay
  // The tod_* trio is meaningless unless gating is on, so it travels together.
  if (point.todMode) {
    out.todMode = point.todMode
    out.todStart = point.todStart
    out.todEnd = point.todEnd
  }
  if (point.region) out.region = point.region
  else if (point.landmark) out.landmark = point.landmark
  return out
}

// Compact, not pretty-printed. This is a generated artifact that is read by
// `atlas:import` and never by a human — indenting it added ~2 MB of leading
// whitespace to the committed repo for no benefit. Reviewers read the counts
// printed by this script and the meta block, not 6,455 JSON records.
function writeJson(file, value) {
  fs.writeFileSync(file, `${JSON.stringify(value)}\n`, 'utf8')
  return fs.statSync(file).size
}

// `meta` alone stays indented. It is ~2.6 KB and it is the part a reviewer and
// the drift check actually read, so a changed source hash shows up as a
// one-line diff instead of being buried in a single-line 200 KB blob.
function writeJsonPretty(file, value) {
  fs.writeFileSync(file, `${JSON.stringify(value, null, 2)}\n`, 'utf8')
  return fs.statSync(file).size
}

function main() {
  const args = parseArgs(process.argv.slice(2))
  if (args.help || !args.servuo) {
    process.stdout.write(USAGE)
    process.exit(args.help ? 0 : 1)
  }

  const atlas = build(args)
  fs.mkdirSync(args.out, { recursive: true })

  // Points shard per facet; everything else is small enough to share one index.
  let totalBytes = 0
  for (const facet of atlas.facets) {
    const file = path.join(args.out, `spawnAtlas.${normalizeFacet(facet)}.json`)
    const facetPoints = atlas.points
      .filter((point) => point.facet === facet)
      .map(encodePoint)
    totalBytes += writeJson(file, { facet, points: facetPoints })
    process.stdout.write(`  ${path.basename(file)}  ${facetPoints.length} points\n`)
  }

  const metaFile = path.join(args.out, 'spawnAtlas.meta.json')
  totalBytes += writeJsonPretty(metaFile, atlas.meta)

  const indexFile = path.join(args.out, 'spawnAtlas.index.json')
  totalBytes += writeJson(indexFile, {
    facets: atlas.facets,
    creatures: atlas.creatures,
    regions: atlas.regions,
    landmarks: atlas.landmarks,
    champions: atlas.champions,
  })

  const c = atlas.meta.counts
  process.stdout.write(
    `  ${path.basename(indexFile)}  ${c.creatures} creatures, ${c.regions} regions, ` +
      `${c.landmarks} landmarks, ${c.champions} champions\n` +
      `\nAtlas built: ${c.points} points across ${c.facets} facets ` +
      `(${c.pointsDisabled} disabled spawners skipped, ` +
      `${c.unresolvedPoints} unplaced), ${(totalBytes / 1024 / 1024).toFixed(2)} MB total.\n` +
      'Commit db/data/spawnAtlas.*.json, then run: npm run atlas:import\n',
  )
}

if (require.main === module) {
  try {
    main()
  } catch (err) {
    process.stderr.write(`atlas:build failed: ${err.message}\n`)
    process.exit(1)
  }
}

module.exports = { build, aggregateCreatures, displayName, encodePoint, ARTIFACT_VERSION }