#!/usr/bin/env python
# This tool takes a tab-delimited textfile as input and creates another column in the file which is the result of
# a computation performed on every row in the original file.  The tool will skip over invalid lines within the file,
# informing the user about the number of lines skipped.  
import sys, re, os.path
from galaxy import eggs
from galaxy.tools import validation
from galaxy.datatypes import metadata
from math import log,exp,sqrt,ceil,floor

assert sys.version_info[:2] >= ( 2, 4 )

def stop_err( msg ):
    sys.stderr.write( msg )
    sys.exit()

inp_file = sys.argv[1]
out_file = sys.argv[2]
expr = sys.argv[3]
round_result = sys.argv[4]
try:
    in_columns = int( sys.argv[5] )
except:
    stop_err( "Missing or invalid 'columns' metadata value, click the pencil icon in the history item and select the Auto-detect option to correct it.  This tool can only be used with tab-delimited data." )
if in_columns < 2:
    # To be considered tabular, data must fulfill requirements of the sniff.is_column_based() method.
    stop_err( "Missing or invalid 'columns' metadata value, click the pencil icon in the history item and select the Auto-detect option to correct it.  This tool can only be used with tab-delimited data." )
try:
    in_column_types = sys.argv[6].split( ',' )
except:
    stop_err( "Missing or invalid 'column_types' metadata value, click the pencil icon in the history item and select the Auto-detect option to correct it.  This tool can only be used with tab-delimited data." )
if len( in_column_types ) != in_columns:
    stop_err( "The 'columns' metadata setting does not conform to the 'column_types' metadata setting, click the pencil icon in the history item and select the Auto-detect option to correct it.  This tool can only be used with tab-delimited data." )
    
# Unescape if input has been escaped
mapped_str = {
    '__lt__': '<',
    '__le__': '<=',
    '__eq__': '==',
    '__ne__': '!=',
    '__gt__': '>',
    '__ge__': '>=',
    '__sq__': '\'',
    '__dq__': '"',
}
for key, value in mapped_str.items():
    expr = expr.replace( key, value )

# Prepare the column variable names and wrappers for column data types
cols, type_casts = [], []
for col in range( 1, in_columns + 1 ):
    col_name = "c%d" % col
    cols.append( col_name )
    col_type = in_column_types[ col - 1 ].strip()
    if round_result == 'no' and col_type == 'int':
        col_type = 'float'
    type_cast = "%s(%s)" % ( col_type, col_name )
    type_casts.append( type_cast )
        
col_str = ', '.join( cols )    # 'c1, c2, c3, c4'
type_cast_str = ', '.join( type_casts )  # 'str(c1), int(c2), int(c3), str(c4)'
assign = "%s = line.split( '\\t' )" % col_str
wrap = "%s = %s" % ( col_str, type_cast_str )
skipped_lines = 0
first_invalid_line = 0
invalid_line = None
lines_kept = 0
total_lines = 0
out = open( out_file, 'wt' )

# Read input file, skipping invalid lines, and perform computation that will result in a new column
code = '''
for i, line in enumerate( file( inp_file ) ):
    total_lines += 1
    line = line.rstrip( '\\r\\n' )
    if not line or line.startswith( '#' ):
        skipped_lines += 1
        if not invalid_line:
            first_invalid_line = i + 1
            invalid_line = line
        continue
    try:
        %s
        %s
        new_val = %s
        if round_result == "yes":
            new_val = int( round( new_val ) )
        new_line = line + '\\t' + str( new_val )
        print >> out, new_line
        lines_kept += 1
    except:
        skipped_lines += 1
        if not invalid_line:
            first_invalid_line = i + 1
            invalid_line = line
''' % ( assign, wrap, expr )

valid_expr = True
try:
    exec code
except Exception, e:
    out.close()
    if str( e ).startswith( 'invalid syntax' ):
        valid_expr = False
        stop_err( 'Expression "%s" likely invalid. See tool tips, syntax and examples.' % expr )
    else:
        stop_err( str( e ) )

if valid_expr:
    out.close()
    valid_lines = total_lines - skipped_lines
    print 'Creating column %d with expression %s' % ( in_columns + 1, expr )
    if valid_lines > 0:
        print 'kept %4.2f%% of %d lines.' % ( 100.0*lines_kept/valid_lines, total_lines )
    else:
        print 'Possible invalid expression "%s" or non-existent column referenced. See tool tips, syntax and examples.' % expr
    if skipped_lines > 0:
        print 'Skipped %d invalid lines starting at line #%d: "%s"' % ( skipped_lines, first_invalid_line, invalid_line )