// 所有关系来自编译器；这里只按源码位置选择符号和分组显示。
function contains(range, position) {
  const compare = (left, right) => left.line - right.line || left.character - right.character;
  return compare(range.start, position) <= 0 && compare(position, range.end) < 0;
}

// 自动分派用于调用层级；不能抢走显式绑定或 Port 声明的“转到定义”。
const generated = new Set(['verify', 'rest-field', 'rest-model', 'adapter']);
function at(index, file, position) {
  const calls = index.calls.filter(call => !generated.has(call.kind) && call.site.file === file && contains(call.site, position));
  const targets = new Set(calls.map(call => call.callee));
  if (targets.size) return index.symbols.filter(symbol => targets.has(symbol.id));
  return index.symbols.filter(symbol => symbol.declarations.some(location =>
    location.file === file && contains(location, position)));
}

function relations(index, id, incoming) {
  const grouped = new Map();
  for (const call of index.calls) {
    if ((incoming ? call.callee : call.caller) !== id) continue;
    const target = incoming ? call.caller : call.callee;
    if (!grouped.has(target)) grouped.set(target, []);
    grouped.get(target).push(call);
  }
  return [...grouped].map(([id, calls]) => ({ symbol: index.symbols.find(symbol => symbol.id === id), calls }));
}

module.exports = { at, relations, contains };