#!/usr/bin/env python

# Copyright 2007 Nanorex, Inc.  See LICENSE file for details.
"""
simplify-reloads - executable python script to remove reload_once lines

$Id$

This is a standalone script (which depends on some code in cad/src)
to remove the first two lines from three-line groups that look like this:

  import MODULE
  reload_once(MODULE)
  from MODULE import SYMBOLS

The MODULE might be a simple or dotted module name (e.g. Overlay or exprs.Overlay).

Usage: ./simplify-reloads file1.py file2.py ...
saves the modified file1.py into FIXED-file1.py, same for file2.py, etc,
but if there were no changes removes FIXED-file1.py instead,
with prints to stderr summarizing the changes or having other debug info.
(no prints to stdout)
"""

__author__ = "bruce"

# algorithm: match individual lines to these patterns (assume no continuation lines need to be handled).
# find groups of three lines which match the three patterns in order, using the same Names, and modify them.


DEBUG = True # various debug prints to stderr
DEBUG_REJECTS = False # debug print for each match failure
DEBUG_MATCHES = False # debug print for each match success

DEBUG_JUST_PRINT_THE_TOKENS = False # if True, just print the tokens nicely, to stdout, and do nothing else.

REALLY_REMOVE_FILES = True # call os.remove on output files we might write anew (whether or not we actually do so)
    # (only matters if not OVERWRITE_ORIGINAL_FILES)

OVERWRITE_ORIGINAL_FILES = True # remove original files and replace them with modified ones (when they would differ)
    # TODO: really this should be a command-line option, default false,
    # but this is a one-use script, so now that it's debugged I won't bother.

from tokenize import generate_tokens
from tokenize import tok_name # dictionary, token (int, used in generate_tokens retval) to its name (e.g. 'NEWLINE')

import sys, os

if __name__ == '__main__':
    thisdir = os.path.dirname(__file__)
##    if thisdir != '.':
##        print >> sys.stderr, "running in directory %r" % (thisdir,)
    cad_src_dir = os.path.join( thisdir, "../..") # location of cad/src directory
    sys.path.append( cad_src_dir )

# ==

# ISSUE: in parse_utils, IGNORED_TOKNAMES = ('NL', 'COMMENT')  -- they might be bad here -- make them a parameter of TokenType? ###TODO

from parse_utils import parse_top, Op, TokenType, Seq, Name, Newline, Optional

def invert_dict(dict1): #bruce 050705 (modified from version in bond_constants.py, should refile)
    res = {}
    for key, val in dict1.items():
        res[val] = key
    assert len(res) == len(dict1), "dict passed to invert_dict had nonunique values"
    return res

_toktype_from_name = invert_dict(tok_name)

def token_with_given_name(name):
    return _toktype_from_name[name]

NewlineToken = token_with_given_name('NEWLINE') # fyi: the lines of interest to us all end in this, not NL

def SpecificName( name_string):
    return TokenType('NAME', (lambda token, name_string = name_string: token == name_string) )

def Keyword( keyword_string):
    # note that generate_tokens doesn't know which names are Python keywords, so we can't do this:
    ## return TokenType('KEYWORD', (lambda token, keyword_string = keyword_string: token == keyword_string) )
    return SpecificName( keyword_string)

IMPORT = Keyword('import')
FROM = Keyword('from')
RELOAD_ONCE = SpecificName('reload_once')

LeftParen = Op('(')
RightParen = Op(')')

ModuleName = Seq( Name, Optional( Seq( Op('.'), Name )))
    # note: this matches module names containing 0 or 1 dot;
    # if we need to match more dots
    # we could make it recursive using ForwardDef, or just lengthen it.

def describe_logical_line_tokens(line_tokens):
    assert line_tokens[0][-1] == line_tokens[-1][-1]
    return line_tokens[0][-1] # their common logical line

def tok_srow( token):
    toktype, tokstring, (srow, scol), (erow, ecol), line = token
    return srow # WARNING: first line is srow 1 but is index 0!

def prepend_to_basename( prefix, filename):
    dir, file = os.path.split(filename)
    return os.path.join( dir, prefix + file)

class _linepat:
    """
    A pattern for one logical line, containing a ModuleName which we can return if it matches.
    """
    def __init__(self, pattern, namepos = None, debugname = None, incomplete_ok = False):
        assert namepos is not None
        assert debugname is not None
        self.pattern = pattern
        self.namepos = namepos
        self.debugname = debugname
        self.incomplete_ok = incomplete_ok # ok to match just the first part of the line?
        return
    def match_to_line_tokens(self, line_tokens):
        """
        line_tokens is a list of tokens (which are tuples as returned by generate_tokens),
        corresponding to a single logical line (i.e. all with the same last element);
        return None if we don't match it,
        or the matched ModuleName within it if we do (NOT as a single string,
        but as a nested list of strings that needs flattening -- should fix someday).
        """
        pat = self.pattern
        res, newrest = parse_top( pat, line_tokens)
        if newrest is None:
            # note: this is how parse_top returns a parse failure or syntax error
            # (with res being a string error message)
            if DEBUG_REJECTS:
                why = res
                print >> sys.stderr, "fyi: %r rejecting line %r because %s" % (self, describe_logical_line_tokens(line_tokens), why)
            return None
        if not self.incomplete_ok:        
            if newrest:
                # not all of the logical line was matched
                if DEBUG_REJECTS:
                    print >> sys.stderr, "fyi: %r rejecting line %r due to incomplete match" % \
                          (self, describe_logical_line_tokens(line_tokens))
                return None
        if DEBUG_MATCHES:
            print >> sys.stderr, "fyi: %r matchline internal res before namepos: %r" % (self, res,)
        res1 = res[self.namepos]
        ### TODO: join it into a proper string -- not needed yet, we only compare it for equality,
        # and it looks like ['exprs', ['.', 'Rect']] which will compare fine.
        if DEBUG_MATCHES:
            print >> sys.stderr, "fyi: %r match returning %r" % (self, res1)
        return res1
    def __repr__(self):
        return "<%s %r at %#x>" % (self.__class__.__name__, self.debugname, id(self))
    pass


# Line patterns
# note: whitespace is implicitly skipped by generate_tokens

Line1 = _linepat( 
            Seq( IMPORT, ModuleName, Newline ), 
            namepos = 1,
            debugname = "Line1"
        )

Line2 = _linepat( 
            Seq( RELOAD_ONCE, LeftParen, ModuleName, RightParen, Newline),
            namepos = 2,
            debugname = "Line2"
        )

Line3 = _linepat( 
            Seq( FROM, ModuleName, IMPORT), # no Newline since we don't care what comes next on that line
            namepos = 1,
            debugname = "Line3",
            incomplete_ok = True
        )

# ==

def process_filename(filename):
    print >> sys.stderr, "processing file %r" % filename
        # always print this, so user knows which file any error messages are about
    file = open(filename, 'rU')
    if OVERWRITE_ORIGINAL_FILES:
        res = process_file(file, filename, overwrite = True) # this closes file itself, before removing/rewriting it
    else:
        res = process_file(file, prepend_to_basename("FIXED-", filename))
        file.close()
    ### TODO: 
##    if res:
##        print >> sys.stderr, "moving fixed file over original one, backing up original"
##        # or just let svn diff/revert serve to "back up original"?
    return

def process_file(file, output_filename, overwrite = False):
    """
    Remove some lines from file and save the result into a new file of the given name,
    unless no lines would be removed,
    in which case just remove the output file if it was present (and if not overwrite).
    Overwrite option revises behavior for when output_filename refers to the same file as file:
    don't remove original file then, just close it and rewrite it if it changes.
    Return a boolean saying whether you removed any lines and left an output file.
    """
    if not overwrite:        
        if os.path.isfile(output_filename):
            if REALLY_REMOVE_FILES: 
                print >> sys.stderr, "REMOVING", output_filename
                os.remove(output_filename) # if this fails, let the exception abort the script
            else:
                print >> sys.stderr, "SHOULD REMOVE (unless we remake it)", output_filename
    
    gentok = generate_tokens(file.readline)
        # a generator of all tokens in the file

    if DEBUG_JUST_PRINT_THE_TOKENS:
        last_logical_line = None
        for token in gentok:
            toktype, tokstring, (srow, scol), (erow, ecol), logical_line = token
            if logical_line != last_logical_line:
                print "\nlogical line: [%s]" % (logical_line,) # not to stderr
                    # note: apparent bug in generate_tokens:
                    # after a multiline string literal,
                    # logical_line can be '"""' for the ending NEWLINE token.
            last_logical_line = logical_line
            print "\n%s %r (%d %d) (%d %d)" % (tok_name[toktype], tokstring, srow, scol, erow, ecol) # not to stderr
        return

    # now split them by logical lines (tok[-1] fields)
    # TODO: rewrite to use "groupby"

    donelines = [] # a growing list of logical lines, each being a list of token tuples
    currentline = [] # current logical line (a list of token tuples)
    last_logical_line = None
    
    for token in gentok:
        toktype, tokstring, (srow, scol), (erow, ecol), logical_line = token
        del toktype, tokstring, srow, scol, erow, ecol
        if logical_line != last_logical_line:
            if currentline:
                donelines.append(currentline)
                currentline = []
            last_logical_line = logical_line
        currentline.append(token)
        continue
    if currentline:
        donelines.append(currentline)
        currentline = []
    del currentline
    
    lines = donelines
    del donelines

    if DEBUG:
        print >> sys.stderr, "got %d logical lines" % len(lines)
    
    # now do the matching alg on the lines

    deletes = [] # list of indices of logical lines to delete (only the first of each pair)

    i = 0
    while i < len(lines) - 2:
        m1 = Line1.match_to_line_tokens( lines[i+0] )
        if m1:
            m2 = Line2.match_to_line_tokens( lines[i+1] )
            if m2:
                m3 = Line3.match_to_line_tokens( lines[i+2] )
                if m3:
                    if m1 == m2 == m3:
                        deletes.append(i)
                        i += 2 # avoid overlapping matches
                    else:
                        print >> sys.stderr, "warning: rejected only due to names not the same:", i, m1,m2,m3
        i += 1
        continue

    if deletes:
        print >> sys.stderr, "found %d linepairs to delete" % len(deletes)

        file.seek(0) # rewind the file
        
        textlines = file.readlines()
            # WARNING: these are physical lines!
            # So their numbering doesn't match logical lines,
            # even if the specific lines to be deleted contain no continuations.
            # We have to use the srow/erow token fields instead, to know what physical textlines to delete.

        if DEBUG:
            print >> sys.stderr, "file has %d physical lines" % len(textlines)
        oldlen = len(textlines)
        
        for i in deletes[::-1]: # process in reverse order, to not mess up line numbering as we modify textlines
            logical1 = lines[i][0] # first token to delete
            logical2 = lines[i+1][-1] # last token to delete
            dline1 = tok_srow(logical1) # first physical line number to delete
            dline2 = tok_srow(logical2) # last physical line number to delete
            # turn line numbers (starting 1) into indices (starting 0)
            dline1 -= 1
            dline2 -= 1
            drange = range(dline1, dline2+1) # inclusive range of physical line indices to delete

            if DEBUG:
                if i == deletes[::-1][0]: # print it only for the first one
                    print >> sys.stderr, "\nwill delete these lines:\n" 
                for lineno in drange:
                    print >> sys.stderr, ">>>", textlines[lineno], ### sanity check
                print >> sys.stderr

            for lineno in drange[::-1]:
                del textlines[lineno]

        newlen1 = len(textlines)

        # also delete any lines that exactly match "from exprs.reload import reload_once"
        count1 = count2 = 0
        for i in range(len(textlines))[::-1]:
            if textlines[i].strip() == "from exprs.reload import reload_once":
                del textlines[i]
                count1 += 1
                if 0 < i < len(textlines) - 1:
                    if not textlines[i-1].strip() and not textlines[i].strip():
                        # two blank lines are now adjacent; delete one of them
                        # (the one at index i, which a moment ago had index i+1)
                        del textlines[i]
                        count2 += 1
        if count1:
            print >> sys.stderr, "also deleted %d imports of reload_once and %d subsequent blank lines" % (count1, count2)
        else:
            assert not count2
        
        # now open the output file and print the lines we're not deleting to the output file
        # use output_filename as name of new file

        if overwrite:
            file.close()
            os.remove(output_filename) # the same file, in this case
        
        output = open(output_filename, "w")
        output.writelines(textlines)
        output.close()
        newlen = len(textlines)
        print >> sys.stderr, "wrote %d lines to %r" % (newlen, output_filename)
        assert oldlen - 2 * len(deletes) == newlen1
        assert newlen1 - count1 - count2 == newlen
        
        pass
    else:
        print >> sys.stderr, "no linepairs to delete"
    print >> sys.stderr
    return not not deletes # from process_file

# ==

if __name__ == '__main__':

    for filename in sys.argv[1:]:
        process_filename(filename)
    if DEBUG:
        print >> sys.stderr, "done"

# end