Graph_gff.py

from .ClassSegFeat import *
from tqdm import tqdm
import random
import string

# create global variables to manipulate them in the functions below and to pass them to Functions.py
global Features
global Segments
Segments={}
Features={}

# get the inverted segment
def invert_seg(seg):
    if seg[0]==">":
        inv_seg="<"+seg[1:]
    elif seg[0]=="<":
        inv_seg=">"+seg[1:]
    else:
        print(seg," not invertable")
        return seg
    return inv_seg

# look for a segment in the dict Segments, in one orientation or the other
def search_segment(segment):
    if segment not in Segments:
        if invert_seg(segment) in Segments:
            return invert_seg(segment)
        return False
    return segment


# functions to create the segments and the features

# create a segment with its first feature
def init_seg(line,segment_id,feat_id,strand):
    [chr,start,stop]=[line[0],int(line[1])+1,int(line[2])] # +1 in the start to convert the bed 0-based coordinate to a 1-based system
    # create the segment, store it in the Segments dict
    Segments[segment_id]=Segment(segment_id,feat_id,chr,start,stop,strand)

# create a feature with the first segment its on
def init_feature(line,feature_id,segment_oriented):
    [type,annot,chr,start,stop,strand]=[line[6],line[12],line[4],int(line[7]),int(line[8]),line[10]]
    if feature_id in Features: # if the feature has already been created (in order to store the child), get the child and rewrite it
        childs=Features[feature_id].childs
    else:
        childs=[]
    parent=get_parent(annot,feature_id)
    # add the current segment to the list of segments that have the feature
    segments_list=[segment_oriented]
    # create the feature, store it in the dict Features
    Features[feature_id]=Feature(feature_id,type,chr,start,stop,annot,childs,parent,segments_list,strand,True,False)

# if there is a parent, returns the id of the parent feature and add the child to the parent
def get_parent(annot,feature_id): # check how the parent info is stored in the gff format in general (this is a particular case...) todo
    if (len(annot.split(";"))>1) and (annot.split(";")[1].split("=")[0]=="Parent"):
    # for annotations that look like : ID=LOC_Os01g01010.1:exon_7;Parent=LOC_Os01g01010.1, where the parent is in the field 1
        parent=annot.split(";")[1].split("=")[1].replace(".","_").replace(":","_")
        add_child(parent,feature_id)
    elif (len(annot.split(";"))>2) and (annot.split(";")[2].split("=")[0]=="Parent"):
    # for annotations that look like : ID=LOC_Os01g01010.1;Name=LOC_Os01g01010.1;Parent=LOC_Os01g01010, where the parent is in the field 2
        parent=annot.split(";")[2].split("=")[1].replace(".","_").replace(":","_")
        add_child(parent,feature_id)
    else: parent=""
    return parent

# add a feature to an existing segment
def add_feature(line,seg,new_feat_id,new_strand):
    segment=Segments[seg]
    if not segment.find_feat(new_feat_id)[0]:
        [chr,start,stop]=[line[0],int(line[1])+1,int(line[2])] # +1 in the start to convert the bed 0-based coordinate to a 1-based system
        segment.add_feature(new_feat_id,chr,start,stop,new_strand)

# add a child feature to an existing feature
def add_child(feat,new_child):
    if feat in Features: # if the feature exists, add new_child
        Features[feat].childs.append(new_child)
    else: # create the feature "empty", only with child
        Features[feat]=Feature(feat,"","",0,0,"",[new_child],"",[],"",False,False)

# add a segment to an existing feature
def add_seg(feat_id,new_seg_oriented):
    if new_seg_oriented not in Features[feat_id].segments_list_source:
        Features[feat_id].segments_list_source.append(new_seg_oriented)

# add the position of the feature on its first and last segment
def add_pos(feature_id):
    feature=Features[feature_id]
    feature.pos_start=get_feature_start_on_segment(feature.segments_list_source[0],feature_id)
    feature.pos_stop=get_feature_stop_on_segment(feature.segments_list_source[-1],feature_id)

# handle the Feature object creation
def load_feature_intersect(line,feature_id,seg_oriented):
    if (feature_id not in Features) or (not Features[feature_id].complete): # if the feature doesn't exist or is not complete, create it or complete it
        init_feature(line,feature_id,seg_oriented)
    else: # if it exists, add the current segment to the list of segments that have the existing feature

        # if the feature existing starts and stops at the same positions as the current feature, add_seg
        current_start=int(line[7])
        current_stop=int(line[8])
        feature=Features[feature_id]
        if (current_start==feature.start) and (current_stop==feature.stop):
            add_seg(feature_id,seg_oriented)
        else: # same feature_id, but not same part of the feature -> need to store them in two separate objects
            add_segment_to_discontinuous_feature(line,feature,seg_oriented,current_start,current_stop)

def add_segment_to_discontinuous_feature(line,feature,seg_oriented,current_start,current_stop):
    added=False
    for other_part_id in feature.other_parts_list:
        other_part=Features[other_part_id]
        if (other_part.start==current_start) and (other_part.stop==current_stop): # look for the current part of the feature to add the segment
            add_seg(other_part_id,seg_oriented)
            added=True
    if added==False : # if the right part of the feature was not found, create a new part for the feature
        new_part_name=feature.id+''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(7))
        feature.other_parts_list.append(new_part_name)
        [chr,start,stop]=[line[4],int(line[7]),int(line[8])]
        segments_list=[seg_oriented]
        Features[new_part_name]=Feature(feature.id,feature.type,chr,start,stop,feature.annot,feature.childs,feature.parent,segments_list,feature.strand,True,True)
        new_part_feature=Features[new_part_name]
        new_part_feature.first=False
        new_part_feature.first_part=feature.id
        feature.other_parts_list.append(new_part_name)
        feature.discontinuous=True
        if feature.parent in Features:
            add_child(feature.parent,new_part_name)

# handle the Segment object creation
def load_segment_intersect(line,segment_id,feat_id,strand):
    if segment_id not in Segments: # if the segment doesn't exist, create it and add the current feature to its feat list
        init_seg(line,segment_id,feat_id,strand)
    else: # if it exists, add the current feature to the list of features on the existing segment
        add_feature(line,segment_id,feat_id,strand)


# create a note for the child features that do not have annotation.
def set_note(feature_id): # not universal, depends on the format of the input gff...
    # the note contains information on the function of the feature and is used for statistics on hypothetical/putatives features.
    # in the gff, the notes are only on the "gene" features. it's easier to have it for the childs than to check the parent's note (or the parent's parent). 
    feature=Features[feature_id]
    note=""
    parent_feat=find_parent(feature_id)
    if parent_feat!='':
        annot=Features[parent_feat].annot.split(';')
        if (len(annot)>0) and (annot[-1].split('=')[0]=="Note"):
            note=annot[-1].split('=')[1]
    feature.note=note


# create all the Segment and Feature objects in the dictionnaries Segments and Features
def load_intersect(intersect_path,verbose):
    if not verbose:
        print("Loading the intersection information")
    # open the file with the intersect between the segments and the gff
    total_lines=0
    if verbose:
        total_lines = len(["" for line in open(intersect_path,"r")])
    with open(intersect_path,"r") as intersect_file:  
        for line in tqdm(intersect_file, desc="Loading the intersection information", total=total_lines, unit=" line",disable=not verbose):
            line=line.split()
            # get the ids for the dictionnaries' keys
            feature_id=line[12].split(';')[0].split("=")[1].replace(".","_").replace(":","_")
            segment_id=line[3]
            strand=line[10]
            segment_oriented=line[3]
        
            load_feature_intersect(line,feature_id,segment_oriented)
            load_segment_intersect(line,segment_id,feature_id,strand)

    # for all the features, add the position of the feature on its first and last segment, and the note.
    # cant do it before because for that i need to have all the segments in the list segments_list for each feature.
    for feat_id in Features:
        if Features[feat_id].complete==False:
            print('***',feat_id,Features[feat_id])
        add_pos(feat_id)
        set_note(feat_id)
    # order the dictionnary
    order_dict(Features)

# orders the features so that each features is always preceded by its parent feature (gene -> mrna -> exons, cds, utr). useful for the transfer later.
def order_dict(features_dict):
    copy_Features=dict(features_dict) # stores the features in a copy
    features_dict.clear()# empty dict, to refill it with the features in the right orcer
    for feature_id in copy_Features:
        add_feature_dict(feature_id,copy_Features,features_dict)

# add a feature to the ordered dictionnary
def add_feature_dict(feature_id,old_dict_features,new_dict_features):
    if feature_id not in new_dict_features:
        feature=old_dict_features[feature_id]
        # check that the parent is present
        if feature.parent!='': # recursively find the parent (most of the time a gene)
            add_feature_dict(feature.parent,old_dict_features,new_dict_features)
        # if the feature is discontinuous, check that the other parts are present :
        if feature.discontinuous and feature.first:
            for part_id in feature.other_parts_list:
                add_feature_dict(feature.parent,old_dict_features,new_dict_features)
        # once the parent is present and the other parts are added, add the feature
        new_dict_features[feature_id]=feature

# find the gene parent of a feature
def find_parent(feature_id): # add a check if there is no parent !
    feature=Features[feature_id]
    if feature.parent=='': # no parent, usually a gene
        return feature.id
    else:
        current=feature.parent
        parent_found=False
        while parent_found==False:
            if Features[current].parent=='': # current doesnt have a parent
                return current
            else: # if we didn't find the parent, we go up to the current feature's parent until we find it
                current=Features[current].parent




# functions to generate the graph's gff from the segments and features created with create_seg_feat

# get the feature's start position on the segment (among segments on the source genome)
def get_feature_start_on_segment(seg_id,feat_id):
    s=Segments[search_segment(seg_id)]
    f=Features[find_part_segment_source(s.id,feat_id)]
    if s.get_start(f.id)>=f.start:
        result=1
    else:
        result=f.start-s.get_start(f.id)+1
    return result

# get the feature's stop position on the segment (among segments on the source genome)
def get_feature_stop_on_segment(seg_id,feat_id):
    s=Segments[search_segment(seg_id)]
    f=Features[find_part_segment_source(s.id,feat_id)]
    if s.get_stop(f.id)<=f.stop:
        result=s.get_size(f.id)
    else:
        result=f.stop-s.get_start(f.id)+1
    return result

# generates the annotation for the gff of the graph, with the rank of the segment in the feature
def make_annot_graph(feature_id,segment):
    # get the rank and the total number of ocurrences for the feature
    feature=Features[find_part_segment_source(segment,feature_id)]
    rank=str(feature.segments_list_source.index(segment)+1)
    total=str(len(feature.segments_list_source))
    # create the annotation with the rank information
    annotation=feature.annot+";Rank_occurrence="+rank+";Total_occurrences="+total
    return annotation

def find_part_segment_source(segment,feature_id):
    first_feature=Features[feature_id]
    if segment in first_feature.segments_list_source:
        return feature_id
    else:
        list_parts=first_feature.other_parts_list
        for part in list_parts:
            if segment in Features[part].segments_list_source:
                return part

# create the line for the gff of the graph
def create_line_graph_gff(feature_stranded,segment):
    [strand,feature_id]=[feature_stranded[0:1],feature_stranded[1:]]

    annotation=make_annot_graph(feature_id,segment)
    type=Features[feature_id].type
    start=get_feature_start_on_segment(segment,feature_id)
    stop=get_feature_stop_on_segment(segment,feature_id)
    line=segment+"\tGrAnnot\t"+type+"\t"+str(start)+"\t"+str(stop)+"\t.\t"+strand+"\t.\t"+annotation+"\n"
    return line

# go through all the segments in Segments and prints the gff of the graph, with one line per segment/feature intersection
def graph_gff(graph_gff_path,verbose):
    if not verbose:
        print("Generation of the graph's gff")

    with open(graph_gff_path,'w') as graph_gff_file:
        for segment_stranded in tqdm(Segments,desc="Generation of the graph's gff",unit=" segment",disable=not verbose):
            features_on_seg=Segments[segment_stranded].feature_list # get the list of the features on the segment
            for feature_tuple in features_on_seg: # go through all the segment's features, and print the gff line for each
                feature_id=feature_tuple[0]
                strand=Segments[segment_stranded].get_strand(feature_id)
                feature_stranded=strand+feature_id
                line = create_line_graph_gff(feature_stranded,segment_stranded)
                graph_gff_file.write(line)

# go through all the features in Features and print the gaf of the graph, with one line per feature
def graph_gaf(graph_gaf_path,seg_len,verbose):
    if not verbose:
        print("Generation of the graph's gaf")

    with open(graph_gaf_path,'w') as graph_gaf_file:
        for feature_id in tqdm(Features,desc="Generation of the graph's gaf",unit=" feature",disable=not verbose):
            feature=Features[feature_id]
            feature_segments=feature.segments_list_source
            feature_path=""
            path_length=0
            for segment in feature_segments:
                feature_path+=segment
                path_length+=seg_len[segment[1:]]
            strand=feature.strand
            size=feature.size
            start_on_path=feature.pos_start-1 # -1 to get the position 0-based bed-like
            stop_on_path=start_on_path+size

            line=f'{feature.id}\t{size}\t0\t{size}\t{strand}\t{feature_path}\t{path_length}\t{start_on_path}\t{stop_on_path}\t{size}\t{size}\t255\n'
            graph_gaf_file.write(line)

# creates a dictionnary with the length of the segments : s5->8
def get_segments_length(segments,verbose):
    seg_len={}
    total_lines=0
    if verbose:
        total_lines=len(["" for line in open(segments,"r")])
    with open(segments,'r') as segments_file:
        for line in tqdm(segments_file, desc="Computing the lengths of the segments", total=total_lines, unit=" segment", disable=not verbose):
            line=line.split()
            seg_id=line[1]
            seg_len[seg_id]=len(line[2])
        return seg_len