q

#!/usr/bin/python

# Name      : q (With respect to The Q Continuum)
# Author    : Harel Ben Attia - harelba@gmail.com, harelba @ github, @harelba on twitter
# Requires  : python with sqlite3
# Version   : 0.1
#
#
# q allows performing SQL-like statements on tabular text data.
#
# Its purpose is to bring SQL expressive power to manipulating text data using the Linux command line.
#
# Full Documentation and details in https://github.com/harelba/q
#
# Run with --help for command line details
#

import os,sys
import random
import sqlite3
import gzip
import glob
from optparse import OptionParser
import traceback as tb
import codecs
import locale
import time
import re
from ConfigParser import ConfigParser

DEBUG = False

# Encode stdout properly,
if sys.stdout.isatty():
	STDOUT = codecs.getwriter(sys.stdout.encoding)(sys.stdout)
else:
	STDOUT = codecs.getwriter(locale.getpreferredencoding())(sys.stdout)

SHOW_SQL = False

p = ConfigParser()
p.read([os.path.expanduser('~/.qrc'),'.qrc'])

def get_option_with_default(p,option_type,option,default):
	if not p.has_option('options',option):
		return default
	if option_type == 'boolean':
		return p.getboolean('options',option)
	elif option_type == 'int':
		return p.getint('options',option)
	elif option_type == 'string' : 
		return p.get('options',option)
	elif option_type == 'escaped_string':
		return p.get('options',option).decode('string-escape')
	else:
		raise Exception("Unknown option type")

default_beautify = get_option_with_default(p,'boolean','beautify',False)
default_gzipped = get_option_with_default(p,'boolean','gzipped',False)
default_delimiter = get_option_with_default(p,'escaped_string','delimiter',None)
default_header_skip = get_option_with_default(p,'int','header_skip',0)
default_formatting = get_option_with_default(p,'string','formatting',None)
default_encoding = get_option_with_default(p,'string','encoding','UTF-8')

parser = OptionParser()
parser.add_option("-b","--beautify",dest="beautify",default=default_beautify,action="store_true",
                help="Beautify output according to actual values. Might be slow...")
parser.add_option("-z","--gzipped",dest="gzipped",default=default_gzipped,action="store_true",
                help="Data is gzipped. Useful for reading from stdin. For files, .gz means automatic gunzipping")
parser.add_option("-d","--delimiter",dest="delimiter",default=default_delimiter,
                help="Field delimiter. If none specified, then standard whitespace is used as a delimiter")
parser.add_option("-t","--tab-delimited-with-header",dest="tab_delimited_with_header",default=False,action="store_true",
                help="Same as -d <tab> -H 1. Just a shorthand for handling standard tab delimited file with one header line at the beginning of the file")
parser.add_option("-H","--header-skip",dest="header_skip",default=default_header_skip,
                help="Skip n lines at the beginning of the data (still takes those lines into account in terms of structure)")
parser.add_option("-f","--formatting",dest="formatting",default=default_formatting,
                help="Output-level formatting, in the format X=fmt,Y=fmt etc, where X,Y are output column numbers (e.g. 1 for first SELECT column etc.")
parser.add_option("-e","--encoding",dest="encoding",default=default_encoding,
                help="Input file encoding. Defaults to UTF-8. set to none for not setting any encoding - faster, but at your own risk...")

class Sqlite3DB(object):
	def __init__(self,show_sql=SHOW_SQL):
		self.show_sql = show_sql
		self.conn = sqlite3.connect(':memory:')
		self.cursor = self.conn.cursor()
		self.type_names = { str : 'TEXT' , int : 'INT' , float : 'FLOAT' }

	def execute_and_fetch(self,q):
		try:
			if self.show_sql:
				print q
			self.cursor.execute(q)
			result = self.cursor.fetchall()
		finally:
			pass#cursor.close()
		return result

	def _get_as_list_str(self,l,quote=False):
		if not quote:
			return ",".join(["%s" % x for x in l])
		else:
			return ",".join(["\"%s\"" % x for x in l])

	def generate_insert_row(self,table_name,column_names,col_vals):
		col_names_str = self._get_as_list_str(column_names)
		col_vals_str = self._get_as_list_str(col_vals,quote=True)
		return 'INSERT INTO %s (%s) VALUES (%s)' % (table_name,col_names_str,col_vals_str)

	def generate_begin_transaction(self):
		return "BEGIN TRANSACTION"

	def generate_end_transaction(self):
		return "COMMIT"

	# Get a list of column names so order will be preserved (Could have used OrderedDict, but 
        # then we would need python 2.7)
	def generate_create_table(self,table_name,column_names,column_dict):
		# Convert dict from python types to db types
		column_name_to_db_type = dict((n,self.type_names[t]) for n,t in column_dict.iteritems())
		column_defs = ','.join(['%s %s' % (n,column_name_to_db_type[n]) for n in column_names])
		return 'CREATE TABLE %s (%s)' % (table_name,column_defs)


	def generate_insert_row(self,table_name,column_names,col_vals):
		col_names_str = self._get_as_list_str(column_names)
		col_vals_str = self._get_as_list_str(col_vals,quote=True)
		return 'INSERT INTO %s (%s) VALUES (%s)' % (table_name,col_names_str,col_vals_str)

	def generate_begin_transaction(self):
		return "BEGIN TRANSACTION"

	def generate_end_transaction(self):
		return "COMMIT"

	# Get a list of column names so order will be preserved (Could have used OrderedDict, but 
        # then we would need python 2.7)
	def generate_create_table(self,table_name,column_names,column_dict):
		# Convert dict from python types to db types
		column_name_to_db_type = dict((n,self.type_names[t]) for n,t in column_dict.iteritems())
		column_defs = ','.join(['%s %s' % (n,column_name_to_db_type[n]) for n in column_names])
		return 'CREATE TABLE %s (%s)' % (table_name,column_defs)

	def generate_temp_table_name(self):
		return "temp_table_%s" % random.randint(0,1000000000)

	def generate_drop_table(self,table_name):
		return "DROP TABLE %s" % table_name

	def drop_table(self,table_name):
		return self.execute_and_fetch(self.generate_drop_table(table_name))	

# Simplistic Sql "parsing" class... We'll eventually require a real SQL parser which will provide us with a parse tree
#
# A "qtable" is a filename which behaves like an SQL table...
class Sql(object):

	def __init__(self,sql):
		# Currently supports only standard SELECT statements

		# Holds original SQL
		self.sql = sql
		# Holds sql parts 
		self.sql_parts = sql.split()
	
		# Set of qtable names
		self.qtable_names = set()
		# Dict from qtable names to their positions in sql_parts. Value here is a *list* of positions,
		# since it is possible that the same qtable_name (file) is referenced in multiple positions
		# and we don't want the database table to be recreated for each reference
		self.qtable_name_positions = {}
		# Dict from qtable names to their effective (actual database) table names
		self.qtable_name_effective_table_names = {}

		# Go over all sql parts
		idx = 0
		while idx < len(self.sql_parts):
			# Get the part string
			part = self.sql_parts[idx]
			# If it's a FROM or a JOIN
			if part.upper() in ['FROM','JOIN']:
				# and there is nothing after it,
				if idx == len(self.sql_parts)-1:
					# Just fail
					raise Exception('FROM/JOIN is missing a table name after it')
				
				
				qtable_name = self.sql_parts[idx+1]
				# Otherwise, the next part contains the qtable name. In most cases the next part will be only the qtable name.
				# We handle one special case here, where this is a subquery as a column: "SELECT (SELECT ... FROM qtable),100 FROM ...". 
				# In that case, there will be an ending paranthesis as part of the name, and we want to handle this case gracefully.
				# This is obviously a hack of a hack :) Just until we have complete parsing capabilities
				if ')' in qtable_name:
					leftover = qtable_name[qtable_name.index(')'):]
					self.sql_parts.insert(idx+2,leftover)
					qtable_name = qtable_name[:qtable_name.index(')')]
					self.sql_parts[idx+1] = qtable_name
					

				self.qtable_names.add(qtable_name)

				if qtable_name not in self.qtable_name_positions.keys():
					self.qtable_name_positions[qtable_name] = []
				
				self.qtable_name_positions[qtable_name].append(idx+1)
				idx += 2
			else:
				idx += 1

	def set_effective_table_name(self,qtable_name,effective_table_name):
		if qtable_name not in self.qtable_names:
			raise Exception("Unknown qtable %s" % qtable_name)
		if qtable_name in self.qtable_name_effective_table_names.keys():
			raise Exception("Already set effective table name for qtable %s" % qtable_name)

		self.qtable_name_effective_table_names[qtable_name] = effective_table_name

	def get_effective_sql(self):
		if len(filter(lambda x: x is None,self.qtable_name_effective_table_names)) != 0:
			raise Exception('There are qtables without effective tables')
		
		effective_sql = [x for x in self.sql_parts]

		for qtable_name,positions in self.qtable_name_positions.iteritems():
			for pos in positions:
				effective_sql[pos] = self.qtable_name_effective_table_names[qtable_name]

		return " ".join(effective_sql)
		
	def execute_and_fetch(self,db):
		return db.execute_and_fetch(self.get_effective_sql())

class LineSplitter(object):
	def __init__(self,delimiter):
		self.delimiter = delimiter

	def split(self,line):
		if line and line[-1] == '\n':
			line = line[:-1]
		if self.delimiter:
			return line.split(self.delimiter)
		else:
			return line.split()

class TableColumnInferer(object):
	def __init__(self,line_splitter):
		self.inferred = False
		self.example_lines = []
		self.line_splitter = line_splitter

	def analyze(self,example_line):
		if self.inferred:
			raise Exception("Already inferred columns")

		# Save the line as an example
		self.example_lines.append(example_line)

		# Column count according to first line only for now
		self.column_count = len(self.line_splitter.split(self.example_lines[0]))

		# FIXME: Hack to provide for some small variation in the column count. Will be fixed as soon as we have better column inferring
		#self.column_count += max(6,int(self.column_count*0.2))
		self.column_count += 5

		if self.column_count == 0:
			raise Exception("Detected a column count of zero... Failing")

		# Only string type for now
		self.column_types = [str for i in range(self.column_count)]
		# Column names are cX starting from 1
		self.column_names = ['c%s' % (i+1) for i in range(self.column_count)]
		# For now, analysis always succeeds
		return True

	def get_column_dict(self):
		return dict(zip(self.column_names,self.column_types))

	def get_column_count(self):
		return self.column_count

	def get_column_names(self):
		return self.column_names

	def get_column_types(self):
		return self.column_types

class TableCreator(object):
	def __init__(self,db,filenames_str,line_splitter,header_skip=0,gzipped=False,encoding='UTF-8'):
		self.db = db
		self.filenames_str = filenames_str
		self.header_skip = header_skip
		self.gzipped = gzipped
		self.table_created = False
		self.line_splitter = line_splitter
		self.encoding = encoding
		self.column_inferer = TableColumnInferer(line_splitter)

		# Filled only after table population since we're inferring the table creation data
		self.table_name = None

		self.buffered_inserts = []

	def get_table_name(self):
		return self.table_name

	def populate(self):
		if self.encoding != 'none' and self.encoding is not None:
			encoder = codecs.getreader(self.encoding)
		else:
			encoder = None
		# Get the list of filenames
		filenames = self.filenames_str.split("+")
		# for each filename (or pattern)
		for fileglob in filenames:
			# Allow either stdin or a glob match
			if fileglob == '-':
				files_to_go_over = ['-']
			else:
				files_to_go_over = glob.glob(fileglob)

			# If there are no files to go over,
			if len(files_to_go_over) == 0:
				raise Exception("File has not been found '%s'" % fileglob)

			# For each match
			for filename in files_to_go_over:
				self.current_filename = filename
				self.lines_read = 0

				# Check if it's standard input or a file 
				if filename == '-':
					f = sys.stdin
				else:
					f = file(filename,'rb')

				# Wrap it with gzip decompression if needed
				if self.gzipped or filename.endswith('.gz'):
					f = gzip.GzipFile(fileobj=f)

				# And wrap it in an decoder (e.g. ascii, UTF-8 etc)
				if encoder is not None:
					f = encoder(f)
					

				# Read all the lines
				try:
					line = f.readline()
					while line:
						self._insert_row(line)
					        line = f.readline()
				finally:
					if f != sys.stdin:
						f.close()
					self._flush_inserts()
				if not self.table_created:
					raise Exception('Table should have already been created for file %s' % filename)

	def _insert_row(self,line):
		# If table has not been created yet
		if not self.table_created:
			# Try to create it along with another "example" line of data
			self.try_to_create_table(line)	

		# If the table is still not created, then we don't have enough data, just return
		if not self.table_created:
			return
		# The table already exists, so we can just add a new row
		self._insert_row_i(line)

	def _insert_row_i(self,line):
		self.lines_read += 1
		if self.lines_read <= self.header_skip:
			return
	        col_vals = line_splitter.split(line)

		# If we have more columns than we inferred
		if len(col_vals) > len(self.column_inferer.column_names):
			raise Exception('Encountered a line in an invalid format %s:%s - %s columns instead of %s. Did you make sure to set the correct delimiter?' % (self.current_filename,self.lines_read,len(col_vals),len(self.column_inferer.column_names)))

		effective_column_names = self.column_inferer.column_names[:len(col_vals)]

		self.buffered_inserts.append((effective_column_names,col_vals))

		if len(self.buffered_inserts) < 1000:
			return
		self._flush_inserts()

	def _flush_inserts(self):
		#print self.db.execute_and_fetch(self.db.generate_begin_transaction())

		for col_names,col_vals in self.buffered_inserts:
			insert_row_stmt = self.db.generate_insert_row(self.table_name,col_names,col_vals)
			self.db.execute_and_fetch(insert_row_stmt)

		#print self.db.execute_and_fetch(self.db.generate_end_transaction())
		self.buffered_inserts = []


	def try_to_create_table(self,line):
		if self.table_created:
			raise Exception('Table is already created')

		# Add that line to the column inferer
		result = self.column_inferer.analyze(line)
		# If inferer succeeded,
		if result:
			# Then generate a temp table name
			self.table_name = self.db.generate_temp_table_name()
			# Get the column definition dict from the inferer
			column_dict = self.column_inferer.get_column_dict()
			# Create the CREATE TABLE statement
			create_table_stmt = self.db.generate_create_table(self.table_name,self.column_inferer.get_column_names(),column_dict)
			# And create the table itself
			self.db.execute_and_fetch(create_table_stmt)
			# Mark the table as created
			self.table_created = True
		else:
			pass # We don't have enough information for creating the table yet

	def drop_table(self):
		if self.table_created:
			self.db.drop_table(self.table_name)

def determine_max_col_lengths(m):
	if len(m) == 0:
		return []
	max_lengths = [0 for x in xrange(0,len(m[0]))]
	for row_index in xrange(0,len(m)):
		for col_index in xrange(0,len(m[0])):
			new_len = len(str(m[row_index][col_index]))
			if new_len > max_lengths[col_index]:
				max_lengths[col_index] = new_len
	return max_lengths
		
(options,args) = parser.parse_args()
if len(args) != 1:
    parser.print_usage()
    sys.exit(1)
	
# Create DB object
db = Sqlite3DB()

# Create SQL statment (command line is 'select' for now, so we add it manually...)
sql_object = Sql('%s' % args[0])

# If the user flagged for a tab-delimited file then set the delimiter to tab
if options.tab_delimited_with_header:
	options.delimiter = '\t'
	options.header_skip = "0"

# Create a line splitter
line_splitter = LineSplitter(options.delimiter)

# Get each "table name" which is actually the file name
for filename in sql_object.qtable_names:
	# Create the matching database table and populate it
	table_creator = TableCreator(db,filename,line_splitter,int(options.header_skip),options.gzipped,options.encoding)
	start_time = time.time()
	table_creator.populate()
	if DEBUG:
		print "TIMING - populate time is %4.3f" % (time.time() - start_time)

	# Replace the logical table name with the real table name
	sql_object.set_effective_table_name(filename,table_creator.table_name)

# Execute the query and fetch the data
m = sql_object.execute_and_fetch(db)

# If the user requested beautifying the output
if options.beautify:
	max_lengths = determine_max_col_lengths(m)

if options.delimiter:
	output_delimiter = options.delimiter
else:
	output_delimiter = " "

if options.formatting:
	formatting_dict = dict([(x.split("=")[0],x.split("=")[1]) for x in options.formatting.split(",")])
else:
	formatting_dict = None

try:
	for rownum,row in enumerate(m):
		row_str = []
		for i,col in enumerate(row):
			if formatting_dict is not None and str(i+1) in formatting_dict.keys():
				fmt_str = formatting_dict[str(i+1)]
			else:
				if options.beautify:
					fmt_str = "%%-%ss" % max_lengths[i]
				else:
					fmt_str = "%s"

			if col is not None:
				row_str.append(fmt_str % col)
			else:
				row_str.append(fmt_str % "")

		STDOUT.write(output_delimiter.join(row_str)+"\n")
except KeyboardInterrupt:
	pass

table_creator.drop_table()