Resolve SabakiHQ#11: Fixing fox's Komi values

This is just the functional part and two test files. Test cases coming
next as well as documentation.

Adjusting Komi on fox is added as an option you can pass to ParseToken.

This handles fox's komi in 3 cases by following kaTrain's fixup:
1. Handicap games it adjusts to 0.5 Komi
2. Even games using chinese rules it adjusts to 7.5 Komi (from 375)
3. From other rulesets it adjusts to (6.5 from 325)

Note: probably a bug here as some games have 0 as Komi and we shouldn't
add Komi in those cases.

src/parse.js

@@ -116,7 +116,8 @@ exports.parseTokens = function(
     getId = (id => () => id++)(0),
     dictionary = null,
     onProgress = () => {},
-    onNodeCreated = () => {}
+    onNodeCreated = () => {},
+    shouldAdjustFoxKomi = true
   } = {}
 ) {
   let node = _parseTokens(new Peekable(tokens), null, {
@@ -126,7 +127,33 @@ exports.parseTokens = function(
     onNodeCreated
   })
 
-  return node.id == null ? node.children : [node]
+  let rootNodes = node.id == null ? node.children : [node]
+
+  // Fox Go Server uses different Komi and in particular for even games will set it to 375.
+  // Here we're following KaTrain's method to fixup Komi
+  // https://github.com/sanderland/katrain/blob/485b55c42df4dd1c77abf21eefc23c9a17d6a512/katrain/core/sgf_parser.py#L422-L430
+  let correctedKomi = 0
+  let gameData = rootNodes[0].data
+  if (
+    shouldAdjustFoxKomi &&
+    'AP' in gameData &&
+    gameData['AP'].includes('foxwq') &&
+    'KM' in gameData
+  ) {
+    if ('HA' in gameData && parseInt(gameData['HA']) >= 1) {
+      correctedKomi = 0.5
+    } else if (
+      'RU' in gameData &&
+      ['chinese', 'cn'].includes(gameData['RU'][0].toLowerCase())
+    ) {
+      correctedKomi = 7.5
+    } else {
+      correctedKomi = 6.5
+    }
+
+    gameData['KM'] = correctedKomi.toString()
+  }
+  return rootNodes
 }
 
 exports.parse = function(contents, options = {}) {

tests/sgf/fox_go_server_komi.sgf

@@ -0,0 +1,10 @@
+(;GM[1]FF[4]
+SZ[19]
+GN[]
+DT[2023-07-22]
+PB[东升712]
+PW[atypclhmn]
+BR[5级]
+WR[5级]
+KM[375]HA[0]RU[Chinese]AP[GNU Go:3.8]RN[1]RE[W+12.75]TM[300]TC[3]TT[30]AP[foxwq]RL[0]
+;B[pd];W[dp];B[dd];W[qp];B[jp];W[nq];B[lq];W[gp];B[hq];W[gq];B[bp];W[cp];B[bq];W[bo];B[dr];W[cn];B[fr];W[gr];B[hr];W[gs];B[fs];W[cf];B[ce];W[df];B[fc];W[cj];B[id];W[jr];B[jq];W[lr];B[kr];W[hp];B[ir];W[mr];B[mq];W[nr];B[np];W[op];B[mp];W[qc];B[qd];W[pc];B[oc];W[ob];B[nb];W[nc];B[od];W[mb];B[pb];W[na];B[qb];W[nd];B[ph];W[rc];B[rb];W[no];B[mo];W[nn];B[pl];W[pj];B[qj];W[qi];B[pi];W[qk];B[oj];W[pk];B[ok];W[qh];B[ql];W[rk];B[rd];W[qg];B[nl];W[mn];B[ln];W[mm];B[ip];W[pg];B[oi];W[js];B[ks];W[ko];B[kp];W[kn];B[lo];W[in];B[og];W[of];B[nf];W[ng];B[oh];W[ne];B[pf];W[mf];B[qf];W[rf];B[rl];W[rj];B[re];W[rn];B[rg];W[rh];B[sf];W[si];B[qn];W[ro];B[pn];W[om];B[ol];W[rm];B[li];W[mi];B[mj];W[lj];B[mh];W[ki];B[lh];W[kk];B[kh];W[ji];B[jh];W[ii];B[lk];W[kl];B[ll];W[ih];B[lm];W[oo];B[ml];W[gf];B[hg];W[fh];B[gg];W[fg];B[ig];W[jc];B[ic];W[jb];B[jf];W[hb];B[ib];W[ia];B[gb];W[hc];B[hd];W[de];B[cd];W[ed];B[ec];W[be];B[bd];W[bf];B[le];W[ld];B[kd];W[lc];B[kc];W[kb];B[jd];W[me];B[lf];W[cq];B[cr];W[ap];B[ar];W[gh];B[km];W[jm];B[io];W[ho];B[jn];W[im];B[kj];W[jj];B[ee];W[fd];B[fe];W[gd];B[ge];W[ff];B[gc];W[hf];B[ha];W[ja];B[if];W[he];B[hh];W[hi];B[ae];W[af];B[ad];W[nh];B[ni];W[mg];B[oe];W[nf];B[sm];W[sk];B[sl];W[sn];B[qo];W[rp];B[on];W[pp];B[nm];W[ef];B[ep];W[eo];B[fp];W[fo];B[fq];W[hn];B[dq];W[ao];B[aq];W[hs];B[is];W[ls];B[lj];W[qm];B[pm];W[ie];B[je];W[oa];B[pa];W[lg];B[kg];W[sh];B[sg];W[jk];B[sc])

tests/sgf/fox_go_server_nokomi.sgf

@@ -0,0 +1,10 @@
+(;GM[1]FF[4]
+SZ[19]
+GN[]
+DT[2023-06-19]
+PB[atypclhmn]
+PW[V911029035]
+BR[6级]
+WR[4级]
+KM[0]HA[1]RU[Chinese]AP[GNU Go:3.8]RN[3]RE[B+R]TM[300]TC[3]TT[30]AP[foxwq]RL[0]
+;B[pq];W[pd];B[cp];W[dc];B[de];W[qo];B[qp];W[po];B[nq];W[eq];B[dn];W[hq];B[pl];W[cg];B[qf];W[nc];B[qd];W[qc];B[rc];W[qb];B[pe];W[qi];B[od];W[pc])