#!/usr/bin/python3
'''Find a safe landing space (i.e. in air, not above lava) near a cluster'''
import sys, math

from util import *
from bisect import insort

def usage():
  print("""Usage:  safe.py [-d n] [filename]
  n is maximum distance of landing to some point in the cluster, default is 10.
  
  Feed stdin with lines from the output of cluster.py, having produced
  air.tsv with the same settings as the cluster input, and lava.tsv
  with a lower-bound on Y of 0""")

n=10.0
if len(sys.argv)>1:
  if sys.argv[1]=='-d':
    sys.argv.pop()
    n=float(sys.argv.pop(1))

if len(sys.argv)>1:
  infile=open(sys.argv.pop(1))
else:
  infile=sys.stdin

class Block:
  '''Shared by Air and Lava,
  holds points and columns.
  Columns are dictionaries indexed by (x,z) coords,
  value is upward-ordered list of pairs, closed intervals of y'''
  def __init__(self,filename):
    with open(filename,'r') as file:
      self.readHeaders(file)
      self.readPoints(file)

    cc=self.columns={}
    tc={}
    for p in self.points:
      k=(p[0],p[2])
      y=p[1]
      try:
        yy=tc[k]
        insort(yy,y)
      except KeyError:
        tc[k]=[y]
    # convert to lists of intervals
    for k,yy in tc.items():
      tyy=[yy]
      ii=[]
      if k==(108.5, -45.5):
        pass
      while True:
        clean=True
        for j,yy in enumerate(tyy):
          if len(yy)==1+(yy[-1]-yy[0]):
            ii.append((yy[0],yy[-1]))
          else:
            clean=False
            for i in range(len(yy)-1):
              if yy[i]+1!=yy[i+1]:
                ii.append((yy[0],yy[i]))
                tyy=[yy[i+1:]]+tyy[j+1:]
            break
        if clean:
          break
      self.columns[k]=set(ii) # so we can merge later

  def readPoints(self,file):
    file.readline()
    self.points=[[float(i) for i in l.split('\t')[2].split(',')] for l in file]

Block.readHeaders=readHeaders # from util

class Air(Block):
  pass

A=Air('air.tsv')

class Lava(Block):
  pass

L=Lava('lava.tsv')

def d(p1,p2):
  dx=p1[0]-p2[0]
  dz=p1[1]-p2[1]
  dy=p1[2]-p2[2]
  return math.sqrt((dx*dx)+(dy*dy)+(dz*dz))

def safety(p):
  ka=[((a[0],a[2]),d(a,p)) for a in A.points if d(a,p)<=n]
  return [(k,A.columns[k[0]],L.columns[k[0]]) for k in ka if k[0] in L.columns]

readHeaders(sys.modules['__main__'],infile,False)
for l in infile:
  c=eval(l)
  ss=[]
  hits={}
  misses=[]
  for p in c:
    ss=safety(p)
    if ss:
      for (k,a,l) in ss:
        try:
          (aa,ll)=hits[k]
          aa.update(a)
          ll.update(l)
        except KeyError:
          hits[k]=(a,l)
    else:
      misses.append(p)
  print(c)
  if hits:
    print(' %s nearby landing columns'%len(hits))
    done={}
    for k in sorted(hits.keys(),key=lambda k:k[1]):
      if k[0] not in done:
        done[k[0]]=1
        aa,ll=hits[k]
        laa=sorted(list(aa))
        print("(%s %s %s)@%0.1f: %s %s"%(k[0][0],laa[0][0],k[0][1],k[1],laa,sorted(list(ll))))
  else:
    print(' No nearby landing zones')

if infile!=sys.stdin:
  infile.close()