# Copyright (c) 2012 Web Notes Technologies Pvt Ltd (http://erpnext.com)
# 
# MIT License (MIT)
# 
# Permission is hereby granted, free of charge, to any person obtaining a 
# copy of this software and associated documentation files (the "Software"), 
# to deal in the Software without restriction, including without limitation 
# the rights to use, copy, modify, merge, publish, distribute, sublicense, 
# and/or sell copies of the Software, and to permit persons to whom the 
# Software is furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in 
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE 
# OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#

"""build query for doclistview and return results"""

import webnotes, json

tables = None
doctypes = {}
roles = []

@webnotes.whitelist()
def get(arg=None):
	"""
	build query
	
	gets doctype, subject, filters
	limit_start, limit_page_length
	"""
	data = webnotes.form_dict
	global tables
	
	if 'query' in data:
		return run_custom_query(data)
	
	filters = json.loads(data['filters'])
	fields = json.loads(data['fields'])
	tables = get_tables()
	load_doctypes()
	
	remove_user_tags(fields)
	# conditions
	conditions = build_conditions(filters)
	
	# query dict
	data['tables'] = ', '.join(tables)
	data['conditions'] = ' and '.join(conditions)
	data['fields'] = ', '.join(fields)
	
	if not data.get('order_by'):
		data['order_by'] = tables[0] + '.modified desc'
		
	if len(tables) > 1:
		data['group_by'] = "group by " + tables[0] + ".name"
	else:
		data['group_by'] = ''

	check_sort_by_table(data.get('order_by'), tables)
	
	add_limit(data)
	
	query = """select %(fields)s from %(tables)s where %(conditions)s
		%(group_by)s order by %(order_by)s %(limit)s""" % data

	return webnotes.conn.sql(query, as_dict=1)

def check_sort_by_table(sort_by, tables):
	"""check atleast 1 column selected from the sort by table """
	tbl = sort_by.split('.')[0]
	if tbl not in tables:
		if tbl.startswith('`'):
			tbl = tbl[4:-1]
		webnotes.msgprint("Please select atleast 1 column from '%s' to sort"\
			% tbl, raise_exception=1)

def run_custom_query(data):
	"""run custom query"""
	query = data['query']
	if '%(key)s' in query:
		query = query.replace('%(key)s', 'name')
	return webnotes.conn.sql(query, as_dict=1, debug=1)

def load_doctypes():
	"""load all doctypes and roles"""
	global doctypes, roles
	import webnotes.model.doctype

	roles = webnotes.get_roles()
		
	for t in tables:
		if t.startswith('`'):
			doctype = t[4:-1]
			if not doctype in webnotes.user.can_get_report:
				webnotes.response['403'] = 1
				raise webnotes.PermissionError
			doctypes[doctype] = webnotes.model.doctype.get(doctype)
	
def remove_user_tags(fields):
	"""remove column _user_tags if not in table"""
	for fld in fields:
		if '_user_tags' in fld:
			if not '_user_tags' in get_table_columns(webnotes.form_dict['doctype']):
				del fields[fields.index(fld)]
				break

def add_limit(data):
	if 'limit_page_length' in data:
		data['limit'] = 'limit %(limit_start)s, %(limit_page_length)s' % data
	else:
		data['limit'] = ''
		
def build_conditions(filters):
	"""build conditions"""
	data = webnotes.form_dict
	
	# docstatus condition
	docstatus = json.loads(data['docstatus'])
	if docstatus:
		conditions = [tables[0] + '.docstatus in (' + ','.join(docstatus) + ')']
	else:
		# default condition
		conditions = [tables[0] + '.docstatus < 2']
	
	# make conditions from filters
	build_filter_conditions(data, filters, conditions)

	# join parent, child tables
	for tname in tables[1:]:
		conditions.append(tname + '.parent = ' + tables[0] + '.name')

	# match conditions
	build_match_conditions(data, conditions)

	return conditions
		
def build_filter_conditions(data, filters, conditions):
	"""build conditions from user filters"""
	for f in filters:
		tname = ('`tab' + f[0] + '`')
		if not tname in tables:
			tables.append(tname)
		
		# prepare in condition
		if f[2]=='in':
			opts = ["'" + t.strip().replace("'", "\'") + "'" for t in f[3].split(',')]
			f[3] = "(" + ', '.join(opts) + ")"
		else:
			f[3] = "'" + f[3].replace("'", "\'") + "'"	
		
		conditions.append(tname + '.' + f[1] + " " + f[2] + " " + f[3])	

def build_match_conditions(data, conditions):
	"""add match conditions if applicable"""
	match_conditions = []
	match = True
	for d in doctypes[data['doctype']]:
		if d.doctype == 'DocPerm':
			if d.role in roles:
				if d.match: # role applicable
					for v in webnotes.user.defaults.get(d.match, ['**No Match**']):
						match_conditions.append('`tab%s`.%s="%s"' % (data['doctype'], d.match,v))
				else:
					match = False
	
	if match_conditions and match:
		conditions.append('('+ ' or '.join(match_conditions) +')')

def get_tables():
	"""extract tables from fields"""
	data = webnotes.form_dict
	tables = ['`tab' + data['doctype'] + '`']

	# add tables from fields
	for f in json.loads(data['fields']):
		table_name = f.split('.')[0]
		if table_name.lower().startswith('group_concat('):
			table_name = table_name[13:]
		# check if ifnull function is used
		if table_name.lower().startswith('ifnull('):
			table_name = table_name[7:]
		if not table_name[0]=='`':
			table_name = '`' + table_name + '`'
		if not table_name in tables:
			tables.append(table_name)	
	return tables

@webnotes.whitelist()
def save_report():
	"""save report"""
	from webnotes.model.doc import Document
	
	data = webnotes.form_dict
	if webnotes.conn.exists('Report', data['name']):
		d = Document('Report', data['name'])
	else:
		d = Document('Report')
		d.name = data['name']
		d.ref_doctype = data['doctype']
		
	d.json = data['json']
	d.save()
	webnotes.msgprint("%s saved." % d.name)
	return d.name

@webnotes.whitelist()
def export_query():
	"""export from report builder"""
	
	# TODO: validate use is allowed to export
	verify_export_allowed()
	ret = get()

	columns = [x[0] for x in webnotes.conn.get_description()]
	data = [['Sr'] + get_labels(columns),]

	# flatten dict
	cnt = 1
	for row in ret:
		flat = [cnt,]
		for c in columns:
			flat.append(row.get(c))
		data.append(flat)
		cnt += 1

	# convert to csv
	from cStringIO import StringIO
	import csv

	f = StringIO()
	writer = csv.writer(f)
	for r in data:
		for i in xrange(len(r)):
			if type(r[i]) is unicode:
				r[i] = r[i].encode('utf-8')
		writer.writerow(r)

	f.seek(0)
	webnotes.response['result'] = f.read()
	webnotes.response['type'] = 'csv'
	webnotes.response['doctype'] = [t[4:-1] for t in tables][0]

def verify_export_allowed():
	"""throw exception if user is not allowed to export"""
	global roles
	roles = webnotes.get_roles()
	if not ('Administrator' in roles or 'System Manager' in roles or 'Report Manager' in roles):
		raise webnotes.PermissionError

def get_labels(columns):
	"""get column labels based on column names"""
	label_dict = {}
	for doctype in doctypes:
		for d in doctypes[doctype]:
			if d.doctype=='DocField' and d.fieldname:
				label_dict[d.fieldname] = d.label
	
	return map(lambda x: label_dict.get(x, x.title()), columns)

@webnotes.whitelist()
def delete_items():
	"""delete selected items"""
	import json
	from webnotes.model import delete_doc
	from webnotes.model.code import get_obj

	il = json.loads(webnotes.form_dict.get('items'))
	doctype = webnotes.form_dict.get('doctype')
	
	for d in il:
		dt_obj = get_obj(doctype, d)
		if hasattr(dt_obj, 'on_trash'):
			dt_obj.on_trash()
		delete_doc(doctype, d)
		
@webnotes.whitelist()
def get_stats():
	"""get tag info"""
	import json
	tags = json.loads(webnotes.form_dict.get('stats'))
	doctype = webnotes.form_dict['doctype']
	stats = {}
	
	columns = get_table_columns(doctype)
	for tag in tags:
		if not tag in columns: continue
		tagcount = webnotes.conn.sql("""select %(tag)s, count(*) 
			from `tab%(doctype)s` 
			where ifnull(%(tag)s, '')!=''
			group by %(tag)s;""" % locals(), as_list=1)
			
		if tag=='_user_tags':
			stats[tag] = scrub_user_tags(tagcount)
		else:
			stats[tag] = tagcount
			
	return stats

def scrub_user_tags(tagcount):
	"""rebuild tag list for tags"""
	rdict = {}
	tagdict = dict(tagcount)
	for t in tagdict:
		alltags = t.split(',')
		for tag in alltags:
			if tag:
				if not tag in rdict:
					rdict[tag] = 0
			
				rdict[tag] += tagdict[t]
	
	rlist = []
	for tag in rdict:
		rlist.append([tag, rdict[tag]])
	
	return rlist

def get_table_columns(table):
	res = webnotes.conn.sql("DESC `tab%s`" % table, as_dict=1)
	if res: return [r['Field'] for r in res]