""" Adapter finding and trimming classes The ...Adapter classes are responsible for finding adapters. The ...Match classes trim the reads. """ import logging from enum import IntFlag from collections import defaultdict from typing import Optional, Tuple, Sequence, Dict, Any, List, Union from abc import ABC, abstractmethod from .align import ( EndSkip, Aligner, PrefixComparer, SuffixComparer, edit_environment, hamming_environment, ) logger = logging.getLogger() class InvalidCharacter(Exception): pass # TODO remove this enum, this should be within each Adapter class class Where(IntFlag): """ Aligner flag combinations for all adapter types. "REFERENCE" is the adapter sequence, "QUERY" is the read sequence """ BACK = EndSkip.QUERY_START | EndSkip.QUERY_STOP | EndSkip.REFERENCE_END FRONT = EndSkip.QUERY_START | EndSkip.QUERY_STOP | EndSkip.REFERENCE_START PREFIX = EndSkip.QUERY_STOP SUFFIX = EndSkip.QUERY_START # Just like FRONT/BACK, but without internal matches FRONT_NOT_INTERNAL = EndSkip.REFERENCE_START | EndSkip.QUERY_STOP BACK_NOT_INTERNAL = EndSkip.QUERY_START | EndSkip.REFERENCE_END ANYWHERE = EndSkip.SEMIGLOBAL def returns_defaultdict_int(): # We need this function to make EndStatistics picklable. # Even a @staticmethod of EndStatistics is not sufficient # as that is not picklable before Python 3.5. return defaultdict(int) class EndStatistics: """Statistics about the 5' or 3' end""" def __init__(self, adapter: "SingleAdapter"): self.max_error_rate: float = adapter.max_error_rate self.sequence: str = adapter.sequence self.effective_length: int = adapter.effective_length self.has_wildcards: bool = adapter.adapter_wildcards self.indels: bool = adapter.indels self.adapter_type: str = adapter.descriptive_identifier() self.allows_partial_matches: bool = adapter.allows_partial_matches # self.errors[l][e] == n iff a sequence of length l matching at e errors was removed n times self.errors: Dict[int, Dict[int, int]] = defaultdict(returns_defaultdict_int) self.adjacent_bases = {"A": 0, "C": 0, "G": 0, "T": 0, "": 0} # TODO avoid hard-coding the list of classes self._remove_prefix = isinstance(adapter, FrontAdapter) def __repr__(self): errors = {k: dict(v) for k, v in self.errors.items()} return "EndStatistics(max_error_rate={}, errors={}, adjacent_bases={})".format( self.max_error_rate, errors, self.adjacent_bases, ) def __iadd__(self, other: Any): if not isinstance(other, self.__class__): raise ValueError("Cannot compare") if ( self.max_error_rate != other.max_error_rate or self.sequence != other.sequence or self.effective_length != other.effective_length or self.indels != other.indels ): raise RuntimeError("Incompatible EndStatistics, cannot be added") for base in ("A", "C", "G", "T", ""): self.adjacent_bases[base] += other.adjacent_bases[base] for length, error_dict in other.errors.items(): for errors in error_dict: self.errors[length][errors] += other.errors[length][errors] return self @property def lengths(self): d = {length: sum(errors.values()) for length, errors in self.errors.items()} return d def random_match_probabilities(self, gc_content: float) -> List[float]: """ Estimate probabilities that this adapter end matches a random sequence. Indels are not taken into account. Returns a list p, where p[i] is the probability that i bases of this adapter match a random sequence with GC content gc_content. """ assert 0.0 <= gc_content <= 1.0 seq = self.sequence # FIXME this is broken for 'anywhere' adapters if self._remove_prefix: seq = seq[::-1] allowed_bases = "CGRYSKMBDHVN" if self.has_wildcards else "GC" p = 1.0 probabilities = [p] for i, c in enumerate(seq): if c in allowed_bases: p *= gc_content / 2.0 else: p *= (1.0 - gc_content) / 2.0 probabilities.append(p) return probabilities class AdapterStatistics(ABC): reverse_complemented: int = 0 name: str adapter: "Adapter" @abstractmethod def __iadd__(self, other): pass @abstractmethod def end_statistics(self) -> Tuple[Optional[EndStatistics], Optional[EndStatistics]]: pass @abstractmethod def add_match(self, match) -> None: pass class SingleAdapterStatistics(AdapterStatistics, ABC): """ Statistics about a 5' or 3' adapter, where we only need to keep track of sequences removed from one "end". """ def __init__(self, adapter: "SingleAdapter"): self.name = adapter.name self.adapter = adapter self.end = EndStatistics(adapter) def __repr__(self): return f"SingleAdapterStatistics(name={self.name}, end={self.end})" def __iadd__(self, other: "SingleAdapterStatistics"): if not isinstance(other, self.__class__): raise ValueError("Cannot iadd") self.end += other.end self.reverse_complemented += other.reverse_complemented return self class FrontAdapterStatistics(SingleAdapterStatistics): def add_match(self, match: "RemoveBeforeMatch"): self.end.errors[match.removed_sequence_length()][match.errors] += 1 def end_statistics(self) -> Tuple[Optional[EndStatistics], Optional[EndStatistics]]: return self.end, None class BackAdapterStatistics(SingleAdapterStatistics): def add_match(self, match: "RemoveAfterMatch"): adjacent_base = match.adjacent_base() self.end.errors[match.removed_sequence_length()][match.errors] += 1 try: self.end.adjacent_bases[adjacent_base] += 1 except KeyError: self.end.adjacent_bases[""] += 1 def end_statistics(self) -> Tuple[Optional[EndStatistics], Optional[EndStatistics]]: return None, self.end class LinkedAdapterStatistics(AdapterStatistics): """ Statistics about sequences removed by a lined adapter. """ def __init__( self, adapter: "LinkedAdapter", front: "SingleAdapter", back: "SingleAdapter", ): self.name = adapter.name self.adapter = adapter self.front = EndStatistics(front) self.back = EndStatistics(back) self.reverse_complemented = 0 def __repr__(self): return f"LinkedAdapterStatistics(name={self.name}, front={self.front}, back={self.back})" def __iadd__(self, other: "LinkedAdapterStatistics"): if not isinstance(other, self.__class__): raise ValueError("Cannot iadd") self.front += other.front self.back += other.back self.reverse_complemented += other.reverse_complemented return self def add_match(self, match: "LinkedMatch"): # TODO this is duplicated code if match.front_match: self.front.errors[match.front_match.removed_sequence_length()][ match.front_match.errors ] += 1 if match.back_match: adjacent_base = match.back_match.adjacent_base() self.back.errors[match.back_match.removed_sequence_length()][ match.back_match.errors ] += 1 try: self.back.adjacent_bases[adjacent_base] += 1 except KeyError: self.back.adjacent_bases[""] += 1 def end_statistics(self) -> Tuple[Optional[EndStatistics], Optional[EndStatistics]]: return self.front, self.back class AnywhereAdapterStatistics(AdapterStatistics): """ Statistics about sequences removed by a lined adapter. """ def __init__(self, adapter: "AnywhereAdapter"): self.name = adapter.name self.adapter = adapter self.front = EndStatistics(adapter) self.back = EndStatistics(adapter) self.reverse_complemented = 0 def __repr__(self): return f"AnywhereAdapterStatistics(name={self.name}, front={self.front}, back={self.back})" def __iadd__(self, other: "AnywhereAdapterStatistics"): if not isinstance(other, AnywhereAdapterStatistics): raise ValueError("Cannot add") self.front += other.front self.back += other.back self.reverse_complemented += other.reverse_complemented return self def add_match(self, match: Union["RemoveBeforeMatch", "RemoveAfterMatch"]) -> None: # TODO contains duplicated code from the other add_match() methods if isinstance(match, RemoveBeforeMatch): self.front.errors[match.removed_sequence_length()][match.errors] += 1 else: adjacent_base = match.adjacent_base() self.back.errors[match.removed_sequence_length()][match.errors] += 1 try: self.back.adjacent_bases[adjacent_base] += 1 except KeyError: self.back.adjacent_bases[""] += 1 def end_statistics(self) -> Tuple[Optional[EndStatistics], Optional[EndStatistics]]: return self.front, self.back class Match(ABC): adapter: "Adapter" @abstractmethod def remainder_interval(self) -> Tuple[int, int]: pass @abstractmethod def retained_adapter_interval(self) -> Tuple[int, int]: pass @abstractmethod def get_info_records(self, read) -> List[List]: pass @abstractmethod def trimmed(self, read): pass @abstractmethod def match_sequence(self): pass class SingleMatch(Match, ABC): """ Representation of a single adapter matched to a single string """ __slots__ = [ "astart", "astop", "rstart", "rstop", "score", "errors", "adapter", "sequence", "length", "adjacent_base", ] def __init__( self, astart: int, astop: int, rstart: int, rstop: int, score: int, errors: int, adapter: "SingleAdapter", sequence: str, ): self.astart: int = astart self.astop: int = astop self.rstart: int = rstart self.rstop: int = rstop self.score: int = score self.errors: int = errors self.adapter: SingleAdapter = adapter self.sequence = sequence # Number of aligned characters in the adapter. If there are # indels, this may be different from the number of characters # in the read. self.length: int = astop - astart def __repr__(self): return ( f"{self.__class__.__name__}(astart={self.astart}, astop={self.astop}, " f"rstart={self.rstart}, rstop={self.rstop}, " f"score={self.score}, errors={self.errors})" ) def __eq__(self, other) -> bool: return ( other.__class__ is self.__class__ and self.astart == other.astart and self.astop == other.astop and self.rstart == other.rstart and self.rstop == other.rstop and self.score == other.score and self.errors == other.errors and self.adapter is other.adapter and self.sequence == other.sequence ) def wildcards(self, wildcard_char: str = "N") -> str: """ Return a string that contains, for each wildcard character, the character that it matches. For example, if the adapter ATNGNA matches ATCGTA, then the string 'CT' is returned. If there are indels, this is not reliable as the full alignment is not available. """ wildcards = [ self.sequence[self.rstart + i] for i in range(self.length) if self.adapter.sequence[self.astart + i] == wildcard_char and self.rstart + i < len(self.sequence) ] return "".join(wildcards) def get_info_records(self, read) -> List[List]: seq = read.sequence qualities = read.qualities info = [ "", self.errors, self.rstart, self.rstop, seq[0 : self.rstart], seq[self.rstart : self.rstop], seq[self.rstop :], self.adapter.name, ] if qualities: info += [ qualities[0 : self.rstart], qualities[self.rstart : self.rstop], qualities[self.rstop :], ] else: info += ["", "", ""] return [info] def match_sequence(self): return self.sequence[self.rstart : self.rstop] @abstractmethod def removed_sequence_length(self) -> int: pass class RemoveBeforeMatch(SingleMatch): """A match that removes sequence before the match""" def rest(self) -> str: """ Return the part of the read before this match if this is a 'front' (5') adapter, return the part after the match if this is not a 'front' adapter (3'). This can be an empty string. """ return self.sequence[: self.rstart] def remainder_interval(self) -> Tuple[int, int]: """ Return an interval (start, stop) that describes the part of the read that would remain after trimming """ return self.rstop, len(self.sequence) def retained_adapter_interval(self) -> Tuple[int, int]: return self.rstart, len(self.sequence) def trim_slice(self): # Same as remainder_interval, but as a slice() object return slice(self.rstop, None) def trimmed(self, read): return read[self.rstop :] def removed_sequence_length(self) -> int: return self.rstop class RemoveAfterMatch(SingleMatch): """A match that removes sequence after the match""" def rest(self) -> str: """ Return the part of the read before this match if this is a 'front' (5') adapter, return the part after the match if this is not a 'front' adapter (3'). This can be an empty string. """ return self.sequence[self.rstop :] def remainder_interval(self) -> Tuple[int, int]: """ Return an interval (start, stop) that describes the part of the read that would remain after trimming """ return 0, self.rstart def retained_adapter_interval(self) -> Tuple[int, int]: return 0, self.rstop def trim_slice(self): # Same as remainder_interval, but as a slice() object return slice(None, self.rstart) def trimmed(self, read): return read[: self.rstart] def adjacent_base(self) -> str: return self.sequence[self.rstart - 1 : self.rstart] def removed_sequence_length(self) -> int: return len(self.sequence) - self.rstart def _generate_adapter_name(_start=[1]) -> str: name = str(_start[0]) _start[0] += 1 return name class Matchable(ABC): """Something that has a match_to() method.""" def __init__(self, name: Optional[str], *args, **kwargs): self.name = name @abstractmethod def enable_debug(self): pass @abstractmethod def match_to(self, sequence: str): pass class Adapter(Matchable, ABC): description = "adapter with one component" # this is overriden in subclasses @abstractmethod def spec(self) -> str: """Return string representation of this adapter""" @abstractmethod def create_statistics(self) -> AdapterStatistics: pass @abstractmethod def descriptive_identifier(self) -> str: pass class SingleAdapter(Adapter, ABC): """ This class is used to find a single adapter characterized by sequence, error rate, type etc. within reads. Arguments: sequence (str): The adapter sequence. Will be converted to uppercase. Also, Us will be converted to Ts. max_errors: Maximum allowed errors (non-negative float). If the values is less than 1, this is interpreted as a rate and passed to the aligner. If it is 1 or greater, the value is converted to a rate by dividing it by the number of non-N characters in the sequence. The error rate is the number of errors in the alignment divided by the length of the part of the alignment that matches the adapter. min_overlap: Report a match only if at least this number of bases of the adapter match the read. read_wildcards: Whether IUPAC wildcards in the read are allowed. adapter_wildcards: Whether IUPAC wildcards in the adapter are allowed. name: Optional name of the adapter. If not provided, the name is set to a unique number. indels: Whether indels are allowed in the alignment. """ allows_partial_matches: bool = True def __init__( self, sequence: str, max_errors: float = 0.1, min_overlap: int = 3, read_wildcards: bool = False, adapter_wildcards: bool = True, name: Optional[str] = None, indels: bool = True, ): self.name: str = _generate_adapter_name() if name is None else name super().__init__(self.name) self._debug: bool = False self.sequence: str = sequence.upper().replace("U", "T").replace("I", "N") if not self.sequence: raise ValueError("Adapter sequence is empty") if max_errors >= 1 and self.sequence.count("N") != len(self.sequence): max_errors /= len(self.sequence) - self.sequence.count("N") self.max_error_rate: float = max_errors self.min_overlap: int = min(min_overlap, len(self.sequence)) iupac = frozenset("ABCDGHKMNRSTUVWXY") if adapter_wildcards and not set(self.sequence) <= iupac: for c in self.sequence: if c not in iupac: raise InvalidCharacter( f"Character '{c}' in adapter sequence '{self.sequence}' is " f"not a valid IUPAC code. Use only characters 'ABCDGHIKMNRSTUVWXY'." ) # Optimization: Use non-wildcard matching if only ACGT is used self.adapter_wildcards: bool = adapter_wildcards and not set( self.sequence ) <= set("ACGT") self.read_wildcards: bool = read_wildcards self.indels: bool = indels self.aligner = self._aligner() def _make_aligner(self, flags: int) -> Aligner: # TODO # Indels are suppressed by setting their cost very high, but a different algorithm # should be used instead. indel_cost = 1 if self.indels else 100000 return Aligner( self.sequence, self.max_error_rate, flags=flags, wildcard_ref=self.adapter_wildcards, wildcard_query=self.read_wildcards, indel_cost=indel_cost, min_overlap=self.min_overlap, ) def __repr__(self): return ( "<{cls}(name={name!r}, sequence={sequence!r}, " "max_error_rate={max_error_rate}, min_overlap={min_overlap}, " "read_wildcards={read_wildcards}, " "adapter_wildcards={adapter_wildcards}, " "indels={indels})>".format(cls=self.__class__.__name__, **vars(self)) ) @property def effective_length(self) -> int: return self.aligner.effective_length def enable_debug(self) -> None: """ Print out the dynamic programming matrix after matching a read to an adapter. """ self._debug = True self.aligner.enable_debug() @abstractmethod def _aligner(self): pass @abstractmethod def match_to(self, sequence: str): """ Attempt to match this adapter to the given string. Return a Match instance if a match was found; return None if no match was found given the matching criteria (minimum overlap length, maximum error rate). """ def __len__(self) -> int: return len(self.sequence) class FrontAdapter(SingleAdapter): """A 5' adapter""" description = "regular 5'" def __init__(self, *args, **kwargs): self._force_anywhere = kwargs.pop("force_anywhere", False) super().__init__(*args, **kwargs) def descriptive_identifier(self) -> str: return "regular_five_prime" def _aligner(self) -> Aligner: return self._make_aligner( Where.ANYWHERE.value if self._force_anywhere else Where.FRONT.value ) def match_to(self, sequence: str): """ Attempt to match this adapter to the given read. Return a Match instance if a match was found; return None if no match was found given the matching criteria (minimum overlap length, maximum error rate). """ alignment: Optional[Tuple[int, int, int, int, int, int]] = self.aligner.locate( sequence ) if self._debug: print(self.aligner.dpmatrix) if alignment is None: return None return RemoveBeforeMatch(*alignment, adapter=self, sequence=sequence) def spec(self) -> str: return f"{self.sequence}..." def create_statistics(self) -> FrontAdapterStatistics: return FrontAdapterStatistics(self) class RightmostFrontAdapter(FrontAdapter): """A 5' adapter that prefers rightmost matches""" description = "rightmost 5'" # def __init__(self, *args, **kwargs): # self._force_anywhere = kwargs.pop("force_anywhere", False) # super().__init__(*args, **kwargs) def descriptive_identifier(self) -> str: return "rightmost_five_prime" def _aligner(self) -> Aligner: self.sequence = self.sequence[::-1] aligner = self._make_aligner( Where.ANYWHERE.value if self._force_anywhere else Where.FRONT.value ) self.sequence = self.sequence[::-1] return aligner def match_to(self, sequence: str): """ Attempt to match this adapter to the given read. Return a Match instance if a match was found; return None if no match was found given the matching criteria (minimum overlap length, maximum error rate). """ alignment: Optional[Tuple[int, int, int, int, int, int]] = self.aligner.locate( sequence[::-1] ) if self._debug: print(self.aligner.dpmatrix) if alignment is None: return None ref_start, ref_end, query_start, query_end, score, errors = alignment alignment = ( len(self.sequence) - ref_end, len(self.sequence) - ref_start, len(sequence) - query_end, len(sequence) - query_start, score, errors, ) return RemoveBeforeMatch(*alignment, adapter=self, sequence=sequence) def spec(self) -> str: return f"{self.sequence}...;rightmost" class BackAdapter(SingleAdapter): """A 3' adapter""" description = "regular 3'" def __init__(self, *args, **kwargs): self._force_anywhere = kwargs.pop("force_anywhere", False) super().__init__(*args, **kwargs) def descriptive_identifier(self) -> str: return "regular_three_prime" def _aligner(self): return self._make_aligner( Where.ANYWHERE.value if self._force_anywhere else Where.BACK.value ) def match_to(self, sequence: str): """ Attempt to match this adapter to the given read. Return a Match instance if a match was found; return None if no match was found given the matching criteria (minimum overlap length, maximum error rate). """ alignment: Optional[Tuple[int, int, int, int, int, int]] = self.aligner.locate( sequence ) if self._debug: print(self.aligner.dpmatrix) # pragma: no cover if alignment is None: return None return RemoveAfterMatch(*alignment, adapter=self, sequence=sequence) def spec(self) -> str: return f"{self.sequence}" def create_statistics(self) -> BackAdapterStatistics: return BackAdapterStatistics(self) class AnywhereAdapter(SingleAdapter): """ An adapter that can be 5' or 3'. If a match involves the first base of the read, it is assumed to be a 5' adapter and a 3' otherwise. """ description = "variable 5'/3'" def descriptive_identifier(self) -> str: return "anywhere" def _aligner(self): return self._make_aligner(Where.ANYWHERE.value) def match_to(self, sequence: str): """ Attempt to match this adapter to the given string. Return a Match instance if a match was found; return None if no match was found given the matching criteria (minimum overlap length, maximum error rate). """ alignment = self.aligner.locate(sequence.upper()) if self._debug: print(self.aligner.dpmatrix) if alignment is None: return None # guess: if alignment starts at pos 0, it’s a 5' adapter if alignment[2] == 0: # index 2 is rstart match = RemoveBeforeMatch(*alignment, adapter=self, sequence=sequence) # type: ignore else: match = RemoveAfterMatch(*alignment, adapter=self, sequence=sequence) # type: ignore return match def spec(self) -> str: return f"...{self.sequence}..." def create_statistics(self) -> AnywhereAdapterStatistics: return AnywhereAdapterStatistics(self) class NonInternalFrontAdapter(FrontAdapter): """A non-internal 5' adapter""" description = "non-internal 5'" def descriptive_identifier(self) -> str: return "noninternal_five_prime" def _aligner(self): return self._make_aligner(Where.FRONT_NOT_INTERNAL.value) def match_to(self, sequence: str): # The locate function takes care of uppercasing the sequence alignment = self.aligner.locate(sequence) if self._debug: try: print(self.aligner.dpmatrix) except AttributeError: pass if alignment is None: return None return RemoveBeforeMatch(*alignment, adapter=self, sequence=sequence) # type: ignore def spec(self) -> str: return f"X{self.sequence}..." class NonInternalBackAdapter(BackAdapter): """A non-internal 3' adapter""" description = "non-internal 3'" def descriptive_identifier(self) -> str: return "noninternal_three_prime" def _aligner(self): return self._make_aligner(Where.BACK_NOT_INTERNAL.value) def match_to(self, sequence: str): # The locate function takes care of uppercasing the sequence alignment = self.aligner.locate(sequence) if self._debug: try: print(self.aligner.dpmatrix) # pragma: no cover except AttributeError: pass if alignment is None: return None return RemoveAfterMatch(*alignment, adapter=self, sequence=sequence) # type: ignore def spec(self) -> str: return f"{self.sequence}X" class PrefixAdapter(NonInternalFrontAdapter): """An anchored 5' adapter""" description = "anchored 5'" allows_partial_matches = False def __init__(self, sequence: str, *args, **kwargs): kwargs["min_overlap"] = len(sequence) super().__init__(sequence, *args, **kwargs) def descriptive_identifier(self) -> str: return "anchored_five_prime" def _aligner(self): if not self.indels: # TODO or if error rate allows 0 errors anyway return PrefixComparer( self.sequence, self.max_error_rate, wildcard_ref=self.adapter_wildcards, wildcard_query=self.read_wildcards, min_overlap=self.min_overlap, ) else: return self._make_aligner(Where.PREFIX.value) def spec(self) -> str: return f"^{self.sequence}..." class SuffixAdapter(NonInternalBackAdapter): """An anchored 3' adapter""" description = "anchored 3'" allows_partial_matches = False def __init__(self, sequence: str, *args, **kwargs): kwargs["min_overlap"] = len(sequence) super().__init__(sequence, *args, **kwargs) def descriptive_identifier(self) -> str: return "anchored_three_prime" def _aligner(self): if not self.indels: # TODO or if error rate allows 0 errors anyway return SuffixComparer( self.sequence, self.max_error_rate, wildcard_ref=self.adapter_wildcards, wildcard_query=self.read_wildcards, min_overlap=self.min_overlap, ) else: return self._make_aligner(Where.SUFFIX.value) def spec(self) -> str: return f"{self.sequence}$" class LinkedMatch(Match): """ Represent a match of a LinkedAdapter """ def __init__( self, front_match: RemoveBeforeMatch, back_match: RemoveAfterMatch, adapter: "LinkedAdapter", ): assert front_match is not None or back_match is not None self.front_match: RemoveBeforeMatch = front_match self.back_match: RemoveAfterMatch = back_match self.adapter: LinkedAdapter = adapter def __repr__(self): return "".format( self.front_match, self.back_match, self.adapter ) @property def score(self): """Number of matching bases""" s = 0 if self.front_match is not None: s += self.front_match.score if self.back_match is not None: s += self.back_match.score return s @property def errors(self): e = 0 if self.front_match is not None: e += self.front_match.errors if self.back_match is not None: e += self.back_match.errors return e def trimmed(self, read): if self.front_match: read = self.front_match.trimmed(read) if self.back_match: read = self.back_match.trimmed(read) return read def remainder_interval(self) -> Tuple[int, int]: matches = [ match for match in [self.front_match, self.back_match] if match is not None ] return remainder(matches) def retained_adapter_interval(self) -> Tuple[int, int]: if self.front_match: start = self.front_match.rstart offset = self.front_match.rstop else: start = offset = 0 if self.back_match: end = self.back_match.rstop + offset else: end = len(self.front_match.sequence) return start, end def get_info_records(self, read) -> List[List]: records = [] for match, namesuffix in [ (self.front_match, ";1"), (self.back_match, ";2"), ]: if match is None: continue record = match.get_info_records(read)[0] record[7] = ( "none" if self.adapter.name is None else self.adapter.name ) + namesuffix records.append(record) read = match.trimmed(read) return records def match_sequence(self): return ( (self.front_match.match_sequence() if self.front_match else "") + "," + (self.back_match.match_sequence() if self.back_match else "") ) class LinkedAdapter(Adapter): """A 5' adapter combined with a 3' adapter""" description = "linked" def __init__( self, front_adapter: SingleAdapter, back_adapter: SingleAdapter, front_required: bool, back_required: bool, name: Optional[str], ): super().__init__(name) self.front_required = front_required self.back_required = back_required # The following attributes are needed for the report self.where = "linked" self.name: str = _generate_adapter_name() if name is None else name self.front_adapter = front_adapter self.front_adapter.name = self.name self.back_adapter = back_adapter def descriptive_identifier(self) -> str: return "linked" def enable_debug(self): self.front_adapter.enable_debug() self.back_adapter.enable_debug() def match_to(self, sequence: str) -> Optional[LinkedMatch]: """ Match the two linked adapters against a string """ front_match = self.front_adapter.match_to(sequence) if self.front_required and front_match is None: return None if front_match is not None: sequence = sequence[front_match.trim_slice()] back_match = self.back_adapter.match_to(sequence) if back_match is None and (self.back_required or front_match is None): return None return LinkedMatch(front_match, back_match, self) def create_statistics(self) -> LinkedAdapterStatistics: return LinkedAdapterStatistics( self, front=self.front_adapter, back=self.back_adapter ) @property def sequence(self): return self.front_adapter.sequence + "..." + self.back_adapter.sequence @property def remove(self): return None def spec(self) -> str: return f"{self.front_adapter.spec()}...{self.back_adapter.spec()}" class MultipleAdapters(Matchable): """ Represent multiple adapters at once """ def __init__(self, adapters: Sequence[Matchable]): super().__init__(name="multiple_adapters") self._adapters = adapters def enable_debug(self): for a in self._adapters: a.enable_debug() def __getitem__(self, item): return self._adapters[item] def __len__(self): return len(self._adapters) def match_to(self, sequence: str) -> Optional[SingleMatch]: """ Find the adapter that best matches the sequence. Return either a Match instance or None if there are no matches. """ best_match = None for adapter in self._adapters: match = adapter.match_to(sequence) if match is None: continue # the score determines which adapter fits best if ( best_match is None or match.score > best_match.score or ( match.score == best_match.score and match.errors < best_match.errors ) ): best_match = match return best_match class IndexedAdapters(Matchable, ABC): """ Represent multiple adapters of the same type at once and use an index data structure to speed up matching. This acts like a "normal" Adapter as it provides a match_to method, but is faster with lots of adapters. There are quite a few restrictions: - the error rate allows at most 2 mismatches - wildcards in the adapter are not allowed - wildcards in the read are not allowed Use the is_acceptable() method to check individual adapters. """ AdapterIndex = Dict[str, Tuple[SingleAdapter, int, int]] def __init__(self, adapters): """All given adapters must be of the same type""" super().__init__(name="indexed_adapters") if not adapters: raise ValueError("Adapter list is empty") for adapter in adapters: self._accept(adapter) self._adapters = adapters self._multiple_adapters = MultipleAdapters(adapters) self._lengths, self._index = self._make_index() logger.debug( "String lengths in the index: %s", sorted(self._lengths, reverse=True) ) if len(self._lengths) == 1: self._length = self._lengths[0] self.match_to = self._match_to_one_length else: self.match_to = self._match_to_multiple_lengths self._make_affix = self._get_make_affix() def __repr__(self): return f"{self.__class__.__name__}(adapters={self._adapters!r})" def match_to(self, sequence: str): """Never called because it gets overwritten in __init__""" @abstractmethod def _get_make_affix(self): pass @abstractmethod def _make_match(self, adapter, length, matches, errors, sequence) -> SingleMatch: pass @classmethod def _accept(cls, adapter): """Raise a ValueError if the adapter is not acceptable""" if adapter.read_wildcards: raise ValueError("Wildcards in the read not supported") if adapter.adapter_wildcards: raise ValueError("Wildcards in the adapter not supported") k = int(len(adapter) * adapter.max_error_rate) if k > 2: raise ValueError("Error rate too high") @classmethod def is_acceptable(cls, adapter): """ Return whether this adapter is acceptable for being used in an index Adapters are not acceptable if they allow wildcards, allow too many errors, or would lead to a very large index. """ try: cls._accept(adapter) except ValueError: return False return True def _make_index(self) -> Tuple[List[int], "AdapterIndex"]: logger.info("Building index of %s adapters ...", len(self._adapters)) index: Dict[str, Tuple[SingleAdapter, int, int]] = dict() lengths = set() has_warned = False for adapter in self._adapters: sequence = adapter.sequence k = int(adapter.max_error_rate * len(sequence)) environment = edit_environment if adapter.indels else hamming_environment for s, errors, matches in environment(sequence, k): if s in index: other_adapter, other_errors, other_matches = index[s] if matches < other_matches: continue if other_matches == matches and not has_warned: logger.warning( "Adapters %s %r and %s %r are very similar. At %s allowed errors, " "the sequence %r cannot be assigned uniquely because the number of " "matches is %s compared to both adapters.", other_adapter.name, other_adapter.sequence, adapter.name, adapter.sequence, k, s, matches, ) has_warned = True else: index[s] = (adapter, errors, matches) lengths.add(len(s)) logger.info("Built an index containing %s strings.", len(index)) return sorted(lengths, reverse=True), index def _match_to_one_length(self, sequence: str): """ Match the adapters against a string and return a Match that represents the best match or None if no match was found """ affix = self._make_affix(sequence.upper(), self._length) if "N" in affix: # Fall back to non-indexed matching return self._multiple_adapters.match_to(sequence) try: adapter, e, m = self._index[affix] except KeyError: return None return self._make_match(adapter, self._length, m, e, sequence) def _match_to_multiple_lengths(self, sequence: str): """ Match the adapters against a string and return a Match that represents the best match or None if no match was found """ affix = sequence.upper() # Check all the prefixes or suffixes (affixes) that could match best_adapter: Optional[SingleAdapter] = None best_length = 0 best_m = -1 best_e = 1000 check_n = True for length in self._lengths: if length < best_m: # No chance of getting the same or a higher number of matches, so we can stop early break affix = self._make_affix(affix, length) if check_n: if "N" in affix: return self._multiple_adapters.match_to(sequence) check_n = False try: adapter, e, m = self._index[affix] except KeyError: continue if m > best_m or (m == best_m and e < best_e): # TODO this could be made to work: # assert best_m == -1 best_adapter = adapter best_e = e best_m = m best_length = length if best_m == -1: return None else: return self._make_match(best_adapter, best_length, best_m, best_e, sequence) def enable_debug(self): pass class IndexedPrefixAdapters(IndexedAdapters): @classmethod def _accept(cls, adapter): if not isinstance(adapter, PrefixAdapter): raise ValueError("Only 5' anchored adapters are allowed") return super()._accept(adapter) def _make_match(self, adapter, length, score, errors, sequence): return RemoveBeforeMatch( astart=0, astop=len(adapter.sequence), rstart=0, rstop=length, score=score, errors=errors, adapter=adapter, sequence=sequence, ) def _get_make_affix(self): return self._make_prefix @staticmethod def _make_prefix(s, n): return s[:n] class IndexedSuffixAdapters(IndexedAdapters): @classmethod def _accept(cls, adapter): if not isinstance(adapter, SuffixAdapter): raise ValueError("Only anchored 3' adapters are allowed") return super()._accept(adapter) def _make_match(self, adapter, length, score, errors, sequence): return RemoveAfterMatch( astart=0, astop=len(adapter.sequence), rstart=len(sequence) - length, rstop=len(sequence), score=score, errors=errors, adapter=adapter, sequence=sequence, ) def _get_make_affix(self): return self._make_suffix @staticmethod def _make_suffix(s, n): return s[-n:] def warn_duplicate_adapters(adapters): d = dict() for adapter in adapters: key = (adapter.__class__, adapter.sequence) if key in d: logger.warning( "Adapter %r (%s) was specified multiple times! " "Please make sure that this is what you want.", adapter.sequence, adapter.description, ) d[key] = adapter.name def remainder(matches: Sequence[Match]) -> Tuple[int, int]: """ Determine which section of the read would not be trimmed. Return a tuple (start, stop) that gives the interval of the untrimmed part relative to the original read. matches must be non-empty """ if not matches: raise ValueError("matches must not be empty") start = 0 for match in matches: match_start, match_stop = match.remainder_interval() start += match_start length = match_stop - match_start return (start, start + length)