#!/usr/bin/env python

#  Copyright (c) 2005 David D. Ding <dding@berkeley.edu>
#
#  This software is distributed under the MIT Open Source License.
#  <http://www.opensource.org/licenses/mit-license.html>
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#  Permission is hereby granted, free of charge, to any person obtaining a 
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"""Read Sequences in interleaved Phylip format (not sequential) and returns a
list of sequences. Phylips is a very common phylogeny generating sequence type
that has the following traits
1) First line contains number of species and number of characters in a species'
sequence. Options can may follow, and they can be spaced or unspaced. Options are
simply letters such as A and W after the number of characters.
2) Options doesn't have to contain U in order for a usertree to appear.
3) If there are options then options appear first, then the sequences. For the
first iteration of sequences the first ten spaces are reserved for names of
options and species, the rest is for sequences.
4) For the second and following iterations the names are removed, only
sequence appears
4) At end of file an usertree may appear. First there is a number that indicts
the number of lines the usertree will take, and then the usertrees follow.

Examples:
  6   50   W
W         0101001111 0101110101 01011	
dmras1    GTCGTCGTTG GACCTGGAGG CGTGG	
hschras   GTGGTGGTGG GCGCCGGCCG TGTGG
ddrasa    GTTATTGTTG GTGGTGGTGG TGTCG
spras     GTAGTTGTAG GAGATGGTGG TGTTG
scras1    GTAGTTGTCG GTGGAGGTGG CGTTG
scras2    GTCGTCGTTG GTGGTGGTGG TGTTG

0101001111 0101110101 01011	
GTCGTCGTTG GACCTGGAGG CGTGG	
GTGGTGGTGG GCGCCGGCCG TGTGG
GTTATTGTTG GTGGTGGTGG TGTCG
GTAGTTGTAG GAGATGGTGG TGTTG
GTAGTTGTCG GTGGAGGTGG CGTTG
GTCGTCGTTG GTGGTGGTGG TGTTG

1					
((dmras1,ddrasa),((hschras,spras),(scras1,scras2)));


"""

from corebio.seq import *

names = ( 'phylip',)
extensions = ('phy',)

def iterseq(fin, alphabet=None):
    """Iterate over the sequences in the file."""
    # Default implementation
    return iter(read(fin, alphabet) )


#Read takes in a phylip file name, read it, processes it, and returns a SeqList
def read(fin, alphabet=None):
    
   
    sequence=[] #where sequences are stored
    idents=[]
    num_seq=0
    num_total_seq=0 #length of sequence of 1 species
    tracker=0 #track what sequence the line is on
    usertree_tracker=0 #track usertree lines
    options='' #options
    num_options=0 #number/lens of options - U

    line=fin.readline()
    while line:
        s_line=line.split() #for ease of use, not used in all scenarios, but easier on the eye

        if s_line == []: #see nothing do nothing
            pass

        elif (s_line[0].isdigit() and len(s_line) == 1 and len(sequence)==num_seq and len(sequence[0])==num_total_seq):    #identifies usertree
            usertree_tracker = int(s_line[0])
            pass
        
        elif num_options > 0:
            if len(sequence) < num_seq:
                if s_line[0][0] in options:
                    num_options -= 1
                    pass
                else:
                    raise ValueError('Not an option, but it should be one')
            else:
                num_options -= 1
                pass
    
        elif usertree_tracker > 0:                    #baskically skip usertree
            if len(sequence[num_seq-1]) == num_total_seq:
                usertree_tracker -=1
                pass
            else:
                raise ValueError('User Tree in Wrong Place')
    
        #####problems parse error unexpected
        elif s_line[0].isdigit():
            if len(s_line) >= 2 and len(sequence) == 0: #identifies first line of file
                num_seq = int(s_line[0])               #get number of sequences
                num_total_seq = int(s_line[1])         #get length of sequences
                if len(s_line) > 2:                   #takes care of the options
                    options= (''.join(s_line[2:]))
                    num_options=len(options) - options.count('U')
            else:
                raise ValueError('parse error') 


    #when options end, this take care of the sequence
        elif num_options == 0:
            if (num_seq==0):
                raise ValueError("Empty File, or possibly wrong file")
            elif tracker < num_seq:
                if num_seq > len(sequence):
                    sequence.append(''.join(line[10:].split())) #removes species name
                    idents.append(line[0:10].strip())
                    tracker +=1
                    
                else:
                    sequence[tracker] += (''.join(s_line))      
                    tracker +=1
                    
                if tracker == num_seq:
                    tracker = 0
                    num_options = len(options)-options.count('U')
        
        line=fin.readline()
   
    if len(sequence) != len(idents) or len(sequence)!=num_seq:
        raise ValueError("Number of different sequences wrong") 
    
    seqs = []
    for i in range (0, len(idents)):
        if len(sequence[i])==num_total_seq:
            seqs.append(Seq(sequence[i], alphabet, idents[i]))
        else:
            raise ValueError("extra sequence in list")
    
    return SeqList(seqs)