--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cpt.py	Mon Jun 05 02:51:35 2023 +0000
@@ -0,0 +1,341 @@
+#!/usr/bin/env python
+from Bio.Seq import Seq, reverse_complement, translate
+from Bio.SeqRecord import SeqRecord
+from Bio import SeqIO
+from Bio.Data import CodonTable
+import logging
+
+logging.basicConfig()
+log = logging.getLogger()
+
+PHAGE_IN_MIDDLE = re.compile("^(?P<host>.*)\s*phage (?P<phage>.*)$")
+BACTERIOPHAGE_IN_MIDDLE = re.compile("^(?P<host>.*)\s*bacteriophage (?P<phage>.*)$")
+STARTS_WITH_PHAGE = re.compile(
+    "^(bacterio|vibrio|Bacterio|Vibrio|)?[Pp]hage (?P<phage>.*)$"
+)
+NEW_STYLE_NAMES = re.compile("(?P<phage>v[A-Z]_[A-Z][a-z]{2}_.*)")
+
+
+def phage_name_parser(name):
+    host = None
+    phage = None
+    name = name.replace(", complete genome.", "")
+    name = name.replace(", complete genome", "")
+
+    m = BACTERIOPHAGE_IN_MIDDLE.match(name)
+    if m:
+        host = m.group("host")
+        phage = m.group("phage")
+        return (host, phage)
+
+    m = PHAGE_IN_MIDDLE.match(name)
+    if m:
+        host = m.group("host")
+        phage = m.group("phage")
+        return (host, phage)
+
+    m = STARTS_WITH_PHAGE.match(name)
+    if m:
+        phage = m.group("phage")
+        return (host, phage)
+
+    m = NEW_STYLE_NAMES.match(name)
+    if m:
+        phage = m.group("phage")
+        return (host, phage)
+
+    return (host, phage)
+
+
+class OrfFinder(object):
+    def __init__(self, table, ftype, ends, min_len, strand):
+        self.table = table
+        self.table_obj = CodonTable.ambiguous_generic_by_id[table]
+        self.ends = ends
+        self.ftype = ftype
+        self.min_len = min_len
+        self.starts = sorted(self.table_obj.start_codons)
+        self.stops = sorted(self.table_obj.stop_codons)
+        self.re_starts = re.compile("|".join(self.starts))
+        self.re_stops = re.compile("|".join(self.stops))
+        self.strand = strand
+
+    def locate(self, fasta_file, out_nuc, out_prot, out_bed, out_gff3):
+        seq_format = "fasta"
+        log.debug("Genetic code table %i" % self.table)
+        log.debug("Minimum length %i aa" % self.min_len)
+
+        out_count = 0
+
+        out_gff3.write("##gff-version 3\n")
+
+        for idx, record in enumerate(SeqIO.parse(fasta_file, seq_format)):
+            for i, (f_start, f_end, f_strand, n, t) in enumerate(
+                self.get_all_peptides(str(record.seq).upper())
+            ):
+                out_count += 1
+
+                descr = "length %i aa, %i bp, from %s..%s[%s] of %s" % (
+                    len(t),
+                    len(n),
+                    f_start,
+                    f_end,
+                    f_strand,
+                    record.description,
+                )
+                fid = record.id + "|%s%i" % (self.ftype, i + 1)
+
+                r = SeqRecord(Seq(n), id=fid, name="", description=descr)
+                t = SeqRecord(Seq(t), id=fid, name="", description=descr)
+
+                SeqIO.write(r, out_nuc, "fasta")
+                SeqIO.write(t, out_prot, "fasta")
+
+                nice_strand = "+" if f_strand == +1 else "-"
+
+                out_bed.write(
+                    "\t".join(
+                        map(str, [record.id, f_start, f_end, fid, 0, nice_strand])
+                    )
+                    + "\n"
+                )
+
+                out_gff3.write(
+                    "\t".join(
+                        map(
+                            str,
+                            [
+                                record.id,
+                                "getOrfsOrCds",
+                                "CDS",
+                                f_start + 1,
+                                f_end,
+                                ".",
+                                nice_strand,
+                                0,
+                                "ID=%s.%s.%s" % (self.ftype, idx, i + 1),
+                            ],
+                        )
+                    )
+                    + "\n"
+                )
+        log.info("Found %i %ss", out_count, self.ftype)
+
+    def start_chop_and_trans(self, s, strict=True):
+        """Returns offset, trimmed nuc, protein."""
+        if strict:
+            assert s[-3:] in self.stops, s
+        assert len(s) % 3 == 0
+        for match in self.re_starts.finditer(s, overlapped=True):
+            # Must check the start is in frame
+            start = match.start()
+            if start % 3 == 0:
+                n = s[start:]
+                assert len(n) % 3 == 0, "%s is len %i" % (n, len(n))
+                if strict:
+                    t = translate(n, self.table)
+                else:
+                    # Use when missing stop codon,
+                    t = "M" + translate(n[3:], self.table, to_stop=True)
+                yield start, n, t  # Edited by CPT to be a generator
+
+    def break_up_frame(self, s):
+        """Returns offset, nuc, protein."""
+        start = 0
+        for match in self.re_stops.finditer(s, overlapped=True):
+            index = match.start() + 3
+            if index % 3 != 0:
+                continue
+            n = s[start:index]
+            for (offset, n, t) in self.start_chop_and_trans(n):
+                if n and len(t) >= self.min_len:
+                    yield start + offset, n, t
+            start = index
+
+    def putative_genes_in_sequence(self, nuc_seq):
+        """Returns start, end, strand, nucleotides, protein.
+        Co-ordinates are Python style zero-based.
+        """
+        nuc_seq = nuc_seq.upper()
+        # TODO - Refactor to use a generator function (in start order)
+        # rather than making a list and sorting?
+        answer = []
+        full_len = len(nuc_seq)
+
+        for frame in range(0, 3):
+            for offset, n, t in self.break_up_frame(nuc_seq[frame:]):
+                start = frame + offset  # zero based
+                answer.append((start, start + len(n), +1, n, t))
+
+        rc = reverse_complement(nuc_seq)
+        for frame in range(0, 3):
+            for offset, n, t in self.break_up_frame(rc[frame:]):
+                start = full_len - frame - offset  # zero based
+                answer.append((start, start - len(n), -1, n, t))
+        answer.sort()
+        return answer
+
+    def get_all_peptides(self, nuc_seq):
+        """Returns start, end, strand, nucleotides, protein.
+
+        Co-ordinates are Python style zero-based.
+        """
+        # Refactored into generator by CPT
+        full_len = len(nuc_seq)
+        if self.strand != "reverse":
+            for frame in range(0, 3):
+                for offset, n, t in self.break_up_frame(nuc_seq[frame:]):
+                    start = frame + offset  # zero based
+                    yield (start, start + len(n), +1, n, t)
+        if self.strand != "forward":
+            rc = reverse_complement(nuc_seq)
+            for frame in range(0, 3):
+                for offset, n, t in self.break_up_frame(rc[frame:]):
+                    start = full_len - frame - offset  # zero based
+                    yield (start - len(n), start, -1, n, t)
+
+
+class MGAFinder(object):
+    def __init__(self, table, ftype, ends, min_len):
+        self.table = table
+        self.table_obj = CodonTable.ambiguous_generic_by_id[table]
+        self.ends = ends
+        self.ftype = ftype
+        self.min_len = min_len
+        self.starts = sorted(self.table_obj.start_codons)
+        self.stops = sorted(self.table_obj.stop_codons)
+        self.re_starts = re.compile("|".join(self.starts))
+        self.re_stops = re.compile("|".join(self.stops))
+
+    def locate(self, fasta_file, out_nuc, out_prot, out_bed, out_gff3):
+        seq_format = "fasta"
+        log.debug("Genetic code table %i" % self.table)
+        log.debug("Minimum length %i aa" % self.min_len)
+
+        out_count = 0
+
+        out_gff3.write("##gff-version 3\n")
+
+        for idx, record in enumerate(SeqIO.parse(fasta_file, seq_format)):
+            for i, (f_start, f_end, f_strand, n, t) in enumerate(
+                self.get_all_peptides(str(record.seq).upper())
+            ):
+                out_count += 1
+
+                descr = "length %i aa, %i bp, from %s..%s[%s] of %s" % (
+                    len(t),
+                    len(n),
+                    f_start,
+                    f_end,
+                    f_strand,
+                    record.description,
+                )
+                fid = record.id + "|%s%i" % (self.ftype, i + 1)
+
+                r = SeqRecord(Seq(n), id=fid, name="", description=descr)
+                t = SeqRecord(Seq(t), id=fid, name="", description=descr)
+
+                SeqIO.write(r, out_nuc, "fasta")
+                SeqIO.write(t, out_prot, "fasta")
+
+                nice_strand = "+" if f_strand == +1 else "-"
+
+                out_bed.write(
+                    "\t".join(
+                        map(str, [record.id, f_start, f_end, fid, 0, nice_strand])
+                    )
+                    + "\n"
+                )
+
+                out_gff3.write(
+                    "\t".join(
+                        map(
+                            str,
+                            [
+                                record.id,
+                                "getOrfsOrCds",
+                                "CDS",
+                                f_start + 1,
+                                f_end,
+                                ".",
+                                nice_strand,
+                                0,
+                                "ID=%s.%s.%s" % (self.ftype, idx, i + 1),
+                            ],
+                        )
+                    )
+                    + "\n"
+                )
+        log.info("Found %i %ss", out_count, self.ftype)
+
+    def start_chop_and_trans(self, s, strict=True):
+        """Returns offset, trimmed nuc, protein."""
+        if strict:
+            assert s[-3:] in self.stops, s
+        assert len(s) % 3 == 0
+        for match in self.re_starts.finditer(s, overlapped=True):
+            # Must check the start is in frame
+            start = match.start()
+            if start % 3 == 0:
+                n = s[start:]
+                assert len(n) % 3 == 0, "%s is len %i" % (n, len(n))
+                if strict:
+                    t = translate(n, self.table)
+                else:
+                    # Use when missing stop codon,
+                    t = "M" + translate(n[3:], self.table, to_stop=True)
+                yield start, n, t
+
+    def break_up_frame(self, s):
+        """Returns offset, nuc, protein."""
+        start = 0
+        for match in self.re_stops.finditer(s, overlapped=True):
+            index = match.start() + 3
+            if index % 3 != 0:
+                continue
+            n = s[start:index]
+            for (offset, n, t) in self.start_chop_and_trans(n):
+                if n and len(t) >= self.min_len:
+                    yield start + offset, n, t
+            start = index
+
+    def putative_genes_in_sequence(self, nuc_seq):
+        """Returns start, end, strand, nucleotides, protein.
+        Co-ordinates are Python style zero-based.
+        """
+        nuc_seq = nuc_seq.upper()
+        # TODO - Refactor to use a generator function (in start order)
+        # rather than making a list and sorting?
+        answer = []
+        full_len = len(nuc_seq)
+
+        for frame in range(0, 3):
+            for offset, n, t in self.break_up_frame(nuc_seq[frame:]):
+                start = frame + offset  # zero based
+                answer.append((start, start + len(n), +1, n, t))
+
+        rc = reverse_complement(nuc_seq)
+        for frame in range(0, 3):
+            for offset, n, t in self.break_up_frame(rc[frame:]):
+                start = full_len - frame - offset  # zero based
+                answer.append((start, start - len(n), -1, n, t))
+        answer.sort()
+        return answer
+
+    def get_all_peptides(self, nuc_seq):
+        """Returns start, end, strand, nucleotides, protein.
+
+        Co-ordinates are Python style zero-based.
+        """
+        # Refactored into generator by CPT
+
+        full_len = len(nuc_seq)
+        for frame in range(0, 3):
+            for offset, n, t in self.break_up_frame(nuc_seq[frame:]):
+                start = frame + offset  # zero based
+                yield (start, start + len(n), +1, n, t)
+        rc = reverse_complement(nuc_seq)
+        for frame in range(0, 3):
+            for offset, n, t in self.break_up_frame(rc[frame:]):
+                start = full_len - frame - offset  # zero based
+                yield (start - len(n), start, -1, n, t)