#!/usr/bin/env python3

from pgtoolkit import toolbase

class BatchQueryTool(toolbase.SimpleTool):

    def __init__(self):

        toolbase.SimpleTool.__init__(self, name='batchquery', desc='Run a query using columns from CSV file as arguments.')

        self.parser.add_argument('--query', dest='query', type=str, help='Query to run. Use %%s for arguments, or %%(name)s for named arguments (see --header).')

        self.parser.add_argument('--file', dest='file', type=str, help='CSV file with data to use as arguments.')

        self.parser.add_argument('--init', dest='init', type=str, help='Query which initialize database session (eg. temporary function).')

        self.parser.add_argument('--output', dest='output', type=str, help='File name for results.')

        self.parser.add_argument('--outputfunc', dest='outputfunc', type=str, help='Python function which will format results (format_row(args, rows)).')

        self.parser.add_argument('--header', dest='header', action='store_true', help='First line of CSV is header with names for columns. These name can be used in query.')

    def _split_line(self, line):

        return [x.strip() for x in line.split(',')]

    def main(self):

        results = []

        # load query from file

        with open(self.args.query, 'r', encoding='utf8') as f:

            query = f.read()

        # connect DB

        with self.pgm.cursor('target') as curs:

            # run init query

            if self.args.init:

                with open(self.args.init, 'r', encoding='utf8') as f:

                    curs.execute(f.read(), [])

            # read CSV file

            with open(self.args.file, 'r', encoding='utf8') as f:

                # read header

                names = None

                if self.args.header:

                    line = f.readline()

                    names = self._split_line(line)

                # read and process lines

                for line in f:

                    args = self._split_line(line)

                    if names:

                        args = dict(zip(names, args))

                    curs.execute(query, args)

                    rows = curs.fetchall()

                    results.append((args, rows))

            curs.connection.commit()

        # write results to output file

        if self.args.output:

            format_row = None

            if self.args.outputfunc:

                with open(self.args.outputfunc, 'r', encoding='utf8') as f:

                    d = dict()

                    exec(f.read(), d)

                    format_row = d['format_row']

            with open(self.args.output, 'w', encoding='utf8') as f:

                for args, rows in results:

                    if format_row:

                        f.write(format_row(args, rows))

                    else:

                        f.write(repr(args))

                        f.write(' -> ')

                        f.write(repr(rows))

                    f.write('\n')

tool = BatchQueryTool()

tool.main()