#!/usr/bin/env python

# Loads a command's CSV output stream into a PostgreSQL table.

# When no command is specified, just cleans up the specified table.

# The command may be run more than once.

import csv

import os.path

import re

import subprocess

import sys

sys.path.append(os.path.dirname(__file__)+"/../lib")

import csvs

import exc

import opts

import sql

import sql_io

import sql_gen

import streams

import strings

import util

def main():

    # Usage

    env_names = []

    def usage_err():

        raise SystemExit('Usage: '+opts.env_usage(env_names)+' '+sys.argv[0]

            +' [input_cmd args...]')

    # Parse args

    input_cmd = sys.argv[1:]

    # Get config from env vars

    table = opts.get_env_var('table', None, env_names)

    schema = opts.get_env_var('schema', 'public', env_names)

    has_row_num = opts.env_flag('has_row_num', True, env_names)

    db_config = opts.get_env_vars(sql.db_config_names, None, env_names)

    verbosity = util.cast(float, opts.get_env_var('verbosity', 3, env_names))

    if not (table != None and 'engine' in db_config): usage_err()

    # Connect to DB

    def log(msg, level=1):

        '''Higher level -> more verbose'''

        if level <= verbosity:

            sys.stderr.write(strings.to_raw_str(msg.rstrip('\n')+'\n'))

    db = sql.connect(db_config, log_debug=log)

    table = sql_gen.Table(table, schema)

    use_copy_from = [True]

    # Loads data into the table using the currently-selected approach.

    def load():

        # Open input stream

        proc = subprocess.Popen(input_cmd, stdout=subprocess.PIPE, bufsize=-1)

        in_ = proc.stdout

        # Get format info

        info = csvs.stream_info(in_, parse_header=True)

        dialect = info.dialect

        if csvs.is_tsv(dialect): use_copy_from[0] = False

        col_names = map(strings.to_unicode, info.header)

        for i, col in enumerate(col_names): # replace empty column names

            if col == '': col_names[i] = 'column_'+str(i)

        # Select schema and escape names

        def esc_name(name): return db.esc_name(name)

        typed_cols = [sql_gen.TypedCol(v, 'text') for v in col_names]

        log('Creating table')

        sql.create_table(db, table, typed_cols, has_pkey=False,

            col_indexes=False)

        # Remove rows from any failed COPY FROM

        sql.truncate(db, table)

        def load_():

            # Create COPY FROM statement

            if use_copy_from[0]:

                copy_from = ('COPY '+table.to_str(db)+' ('

                    +(', '.join(map(esc_name, col_names)))

                    +') FROM STDIN DELIMITER '+db.esc_value(dialect.delimiter)

                    +' NULL '+db.esc_value(''))

                assert not csvs.is_tsv(dialect)

                copy_from += ' CSV'

                if dialect.quoting != csv.QUOTE_NONE:

                    quote_str = db.esc_value(dialect.quotechar)

                    copy_from += ' QUOTE '+quote_str

                    if dialect.doublequote: copy_from += ' ESCAPE '+quote_str

                copy_from += ';\n'

            # Load the data

            line_in = streams.ProgressInputStream(in_, sys.stderr, n=1000)

            try:

                if use_copy_from[0]:

                    log('Using COPY FROM')

                    log(copy_from, level=2)

                    db.db.cursor().copy_expert(copy_from, line_in)

                else:

                    log('Using INSERT')

                    cols_ct = len(col_names)

                    for row in csvs.make_reader(line_in, dialect):

                        row = map(strings.to_unicode, row)

                        util.list_set_length(row, cols_ct) # truncate extra cols

                        sql.insert(db, table, row, cacheable=False, log_level=5)

            finally:

                line_in.close() # also closes proc.stdout

                proc.wait()

            if has_row_num: sql.add_row_num(db, table)

        sql.with_savepoint(db, load_)

    if input_cmd != []:

        try: load()

        except sql.DatabaseErrors, e:

            if use_copy_from[0]: # first try

                exc.print_ex(e, plain=True)

                use_copy_from[0] = False

                load() # try again with different approach

            else: raise

    log('Cleaning up table')

    sql_io.cleanup_table(db, table)

    log('Vacuuming and reanalyzing table')

    sql.vacuum(db, table)

main()