#!/usr/bin/env python

# To do:
# - Let user specify the parser class on the command line.
# - Let user specify a sequence file to BLAST on the net.
# - Script should help debug connection to NCBI website.

from __future__ import print_function

import os
import re
import sys
import getopt
import traceback

from Bio import ParserSupport
from Bio.Blast import NCBIStandalone


CONTEXT = 5   # show 5 lines of context around the error in the format file

USAGE = """%s [-h] [-v] [-p] [-n] [-o] <testfile>

This script helps diagnose problems with the BLAST parser.

OPTIONS:

-h    Show this help file.

-v    Verbose output.

-p    <testfile> is a protein file.

-n    <testfile> is a nucleotide file.

-o    <testfile> is a BLAST output file.

""" % sys.argv[0]


class DebuggingConsumer(object):
    def __init__(self, decorated=None):
        self.linenum = 0
        if decorated is None:
            decorated = ParserSupport.AbstractConsumer()
        self.decorated = decorated
        self._prev_attr = None

    def _decorated_section(self):
        getattr(self.decorated, self._prev_attr)()

    def _decorated(self, data):
        getattr(self.decorated, self._prev_attr)(data)
        self.linenum += 1

    def __getattr__(self, attr):
        self._prev_attr = attr
        if attr.startswith('start_') or attr.startswith('end_'):
            return self._decorated_section
        else:
            return self._decorated


def chomp(line):
    return re.sub(r"[\r\n]*$", "", line)


def choose_parser(outfile):
    data = open(outfile).read()
    ldata = data.lower()
    if "<html>" in ldata or "<pre>" in ldata:
        raise NotImplementedError("Biopython no longer has an HTML BLAST parser.")
    if "results from round)" in ldata or "converged!" in ldata:
        return NCBIStandalone.PSIBlastParser
    return NCBIStandalone.BlastParser


def test_blast_output(outfile):
    # Try to auto-detect the format
    if 1:
        print("No parser specified.  I'll try to choose one for you based")
        print("on the format of the output file.")
        print("")

        parser_class = choose_parser(outfile)
        print("It looks like you have given output that should be parsed")
        print("with %s.%s.  If I'm wrong, you can select the correct parser" %
              (parser_class.__module__, parser_class.__name__))
        print("on the command line of this script (NOT IMPLEMENTED YET).")
    else:
        raise NotImplementedError("Biopython no longer has an HTML BLAST parser.")
    print("")

    scanner_class = parser_class()._scanner.__class__
    consumer_class = parser_class()._consumer.__class__

    # parser_class()._scanner.feed(
    #    open(outfile), ParserSupport.TaggingConsumer())
    print("I'm going to run the data through the parser to see what happens...")
    parser = parser_class()
    try:
        parser.parse_file(outfile)
    except (KeyboardInterrupt, SystemExit):
        raise
    except Exception as err:
        exception_info = str(err)
        print("Dang, the parsing failed.")
    else:
        print("Parsing succeeded, no problems detected.")
        print("However, you should check to make sure the following scanner")
        print("trace looks reasonable.")
        print("")
        parser_class()._scanner.feed(
            open(outfile), ParserSupport.TaggingConsumer())
        return 0
    print("")

    print("Alright.  Let me try and figure out where in the parser the")
    print("problem occurred...")
    etype, value, tb = sys.exc_info()
    ftb = traceback.extract_tb(tb)
    ftb.reverse()
    class_found = None
    for err_file, err_line, err_function, err_text in ftb:
        if hasattr(consumer_class, err_function):
            class_found = consumer_class
            break
        elif hasattr(scanner_class, err_function):
            class_found = scanner_class
            break
    if class_found is None:
        print("Sorry, I could not pinpoint the error to the parser.")
        print("There's nothing more I can tell you.")
        print("Here's the traceback:")
        traceback.print_exception(etype, value, tb)
        return 1
    else:
        print("I found the problem in %s.%s.%s, line %d:" %
              (class_found.__module__, class_found.__name__,
               err_function, err_line))
        print("    %s" % err_text)
        print("This output caused an %s to be raised with the" % etype)
        print("information %r." % exception_info)
    print("")

    print("Let me find the line in the file that triggers the problem...")
    parser = parser_class()
    scanner, consumer = parser._scanner, parser._consumer
    consumer = DebuggingConsumer(consumer)
    try:
        scanner.feed(open(outfile), consumer)
    except etype:
        pass
    else:
        print("Odd, the exception disappeared!  What happened?")
        return 3
    print("It's caused by line %d:" % consumer.linenum)
    lines = open(outfile).readlines()
    start, end = consumer.linenum - CONTEXT, consumer.linenum + CONTEXT + 1
    if start < 0:
        start = 0
    if end > len(lines):
        end = len(lines)
    ndigits = len(str(end))
    for linenum in range(start, end):
        line = chomp(lines[linenum])
        if linenum == consumer.linenum:
            prefix = '*'
        else:
            prefix = ' '

        s = "%s%*d %s" % (prefix, ndigits, linenum, line)
        s = s[:80]
        print(s)
    print("")

    if class_found == scanner_class:
        print("Problems in %s are most likely caused by changed formats." %
              class_found.__name__)
        print("You can start to fix this by going to line %d in module %s." %
              (err_line, class_found.__module__))
        print("Perhaps the scanner needs to be made more lenient by accepting")
        print("the changed format?")
        print("")

        if VERBOSITY <= 0:
            print("For more help, you can run this script in verbose mode")
            print("to see detailed information about how the scanner")
            print("identifies each line.")
        else:
            print("OK, let's see what the scanner's doing!")
            print("")
            print("*" * 20 + " BEGIN SCANNER TRACE " + "*" * 20)
            try:
                parser_class()._scanner.feed(
                    open(outfile), ParserSupport.TaggingConsumer())
            except etype:
                pass
            print("*" * 20 + " END SCANNER TRACE " + "*" * 20)
        print("")

    elif class_found == consumer_class:
        print("Problems in %s can be caused by two things:" %
              class_found.__name__)
        print("    - The format of the line parsed by '%s' changed." %
              err_function)
        print("    - The scanner misidentified the line.")
        print("Check to make sure '%s' should parse the line:" %
              err_function)
        s = "    %s" % chomp(lines[consumer.linenum])
        s = s[:80]
        print(s)
        print("If so, debug %s.%s.  Otherwise, debug %s." %
              (class_found.__name__, err_function, scanner_class.__name__))


VERBOSITY = 0
if __name__ == '__main__':
    try:
        optlist, args = getopt.getopt(sys.argv[1:], "hpnov")
    except getopt.error as err:
        sys.stderr.write("%s\n" % err)
        sys.exit(-1)
    if len(args) != 1:
        sys.stderr.write(USAGE)
        sys.exit(-1)
    TESTFILE, = args
    if not os.path.exists(TESTFILE):
        sys.stderr.write("I could not find file: %s\n" % TESTFILE)
        sys.exit(-1)

    PROTEIN = NUCLEOTIDE = OUTPUT = None
    for opt, arg in optlist:
        if opt == '-h':
            print(USAGE)
            sys.exit(0)
        elif opt == '-p':
            PROTEIN = 1
        elif opt == '-n':
            NUCLEOTIDE = 1
        elif opt == '-o':
            OUTPUT = 1
        elif opt == '-v':
            VERBOSITY += 1

    if len([x for x in (PROTEIN, NUCLEOTIDE, OUTPUT) if x is not None]) != 1:
        OUTPUT = 1
        # sys.stderr.write("Exactly one of -p, -n, or -o should be specified.\n")
        # sys.exit(-1)
    if PROTEIN or NUCLEOTIDE:
        sys.stderr.write("-p and -n not implemented yet\n")
        sys.exit(-1)
    test_blast_output(TESTFILE)
