/**
 * [INPUT]: 无外部依赖(纯函数);入参 map{nodes:[{t,d,ref:[[c,l]]}],pts:[[x,y]]}、cats(课程系列,解析 ref→课节)、doneSet(完成集)、courseIdx
 * [OUTPUT]: buildStarMap(...) → {stars,edges,nodes,stations,mapProg,curIdx,allDone};逐字移植 DC renderVals 几何(源行 2869-2914)
 * [POS]: domain/v4 的星图几何派生,被 StarMapSvg / CourseMap 消费;数据源 data/v4/courses 或 get_learning_maps
 * [PROTOCOL]: 变更时更新此头部，然后检查 CLAUDE.md
 */

const ACCENT = 'var(--zzm-accent,#A6402F)'
const rr = (i, n) => { const x = Math.sin((i + 1) * n) * 43758.5; return x - Math.floor(x) }
const clip = (s) => (s && s.length > 10 ? s.slice(0, 10) + '…' : s || '')

// 22 颗装饰背景星(源行 2894)
function buildStars() {
  return Array.from({ length: 22 }, (_, i) => ({
    x: +(20 + 700 * rr(i, 12.9)).toFixed(1),
    y: +(14 + 372 * rr(i, 78.2)).toFixed(1),
    r: +(0.8 + 1.3 * rr(i, 45.6)).toFixed(2),
    o: +(0.1 + 0.2 * rr(i, 91.3)).toFixed(2),
  }))
}

// 节点前 3 节课预览(源行 2904-2908)：ref→cats[c].ls[l] 解析真实标题 + 完成态
function nodeLessons(ref, cats, isDone, y) {
  const L = ref.slice(0, 3).map((rf, j) => {
    const a2 = cats[rf[0]] && cats[rf[0]].ls[rf[1]]
    const dd = isDone(rf[0], rf[1])
    return { y: y + 48 + j * 14, t: (dd ? '✓ ' : '') + (a2 ? clip(a2[0]) : '（已删除）'), f: dd ? ACCENT : '#8E8E88', w: dd ? 600 : 400 }
  })
  if (ref.length > 3) L.push({ y: y + 48 + 42, t: '… 共 ' + ref.length + ' 节', f: '#B0B0AA', w: 400 })
  return L
}

// 主入口：真实 map(nodes+pts) + cats + 完成集 → 星图几何
export function buildStarMap(map, cats = [], doneSet = new Set(), courseIdx = 0) {
  const NDs = map?.nodes ?? []
  const pts = map?.pts ?? []
  const isDone = (c, l) => doneSet.has(courseIdx + '-' + c + '-' + l)
  const done = NDs.map((nd) => nd.ref.length > 0 && nd.ref.every(([c, l]) => isDone(c, l)))
  let curIdx = done.findIndex((d) => !d)
  const allDone = curIdx < 0
  if (allDone) curIdx = 0

  const edges = pts.slice(1).map((p, i) => {
    const a = pts[i], dnn = i < curIdx || allDone
    return { x1: a[0], y1: a[1], x2: p[0], y2: p[1], c: dnn ? '#1D1D1B' : 'rgba(0,0,0,.17)', w: dnn ? 1.6 : 1.2, d: dnn ? '0' : '3 5' }
  })

  const nodes = NDs.map((nd, i) => {
    const x = pts[i][0], y = pts[i][1], d = done[i], cu = i === curIdx && !allDone && !d
    return {
      x, y, r: d || cu ? 12 : 11,
      fill: d ? '#1D1D1B' : cu ? ACCENT : '#FFFFFF',
      stroke: d ? '#1D1D1B' : cu ? ACCENT : '#C6C6C0',
      mark: d ? '✓' : String(i + 1), mf: d || cu ? '#FFFFFF' : '#71716C', haloR: cu ? 19 : 0,
      sy: y - 26, stn: '第 ' + (i + 1) + ' 站',
      label: nd.t, lf: cu ? '#1D1D1B' : '#6E6E6A', lw: cu ? 600 : 500, my: y + 3.5, ly: y + 31,
      lessons: nodeLessons(nd.ref, cats, isDone, y),
    }
  })

  const stations = NDs.map((nd, i) => {
    const d = done[i], cu = i === curIdx && !allDone && !d
    return {
      mark: d ? '✓' : String(i + 1), bg: d ? '#1D1D1B' : cu ? ACCENT : '#FFFFFF', c: d || cu ? '#FFFFFF' : '#71716C',
      bd: d ? '#1D1D1B' : cu ? ACCENT : '#C6C6C0', w: cu ? 650 : 500, tc: cu ? '#161616' : '#3F3F3B',
      rowBg: cu ? 'rgba(166,64,47,.06)' : 'transparent', title: nd.t, desc: nd.d || '', meta: nd.ref.length + ' 节', index: i,
    }
  })

  return {
    stars: buildStars(), edges, nodes, stations,
    mapProg: done.filter(Boolean).length + ' / ' + NDs.length + ' 站已完成', curIdx, allDone,
  }
}