# Copyright (C) 2018-2019 Garmin Ltd.
#
# SPDX-License-Identifier: GPL-2.0-only
#

from contextlib import closing
import re
import sqlite3
import itertools
import json

UNIX_PREFIX = "unix://"

ADDR_TYPE_UNIX = 0
ADDR_TYPE_TCP = 1

# The Python async server defaults to a 64K receive buffer, so we hardcode our
# maximum chunk size. It would be better if the client and server reported to
# each other what the maximum chunk sizes were, but that will slow down the
# connection setup with a round trip delay so I'd rather not do that unless it
# is necessary
DEFAULT_MAX_CHUNK = 32 * 1024

def setup_database(database, sync=True):
    db = sqlite3.connect(database)
    db.row_factory = sqlite3.Row

    with closing(db.cursor()) as cursor:
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS tasks_v2 (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                method TEXT NOT NULL,
                outhash TEXT NOT NULL,
                taskhash TEXT NOT NULL,
                unihash TEXT NOT NULL,
                created DATETIME,

                -- Optional fields
                owner TEXT,
                PN TEXT,
                PV TEXT,
                PR TEXT,
                task TEXT,
                outhash_siginfo TEXT,

                UNIQUE(method, outhash, taskhash)
                )
            ''')
        cursor.execute('PRAGMA journal_mode = WAL')
        cursor.execute('PRAGMA synchronous = %s' % ('NORMAL' if sync else 'OFF'))

        # Drop old indexes
        cursor.execute('DROP INDEX IF EXISTS taskhash_lookup')
        cursor.execute('DROP INDEX IF EXISTS outhash_lookup')

        # Create new indexes
        cursor.execute('CREATE INDEX IF NOT EXISTS taskhash_lookup_v2 ON tasks_v2 (method, taskhash, created)')
        cursor.execute('CREATE INDEX IF NOT EXISTS outhash_lookup_v2 ON tasks_v2 (method, outhash)')

    return db


def parse_address(addr):
    if addr.startswith(UNIX_PREFIX):
        return (ADDR_TYPE_UNIX, (addr[len(UNIX_PREFIX):],))
    else:
        m = re.match(r'\[(?P<host>[^\]]*)\]:(?P<port>\d+)$', addr)
        if m is not None:
            host = m.group('host')
            port = m.group('port')
        else:
            host, port = addr.split(':')

        return (ADDR_TYPE_TCP, (host, int(port)))


def chunkify(msg, max_chunk):
    if len(msg) < max_chunk - 1:
        yield ''.join((msg, "\n"))
    else:
        yield ''.join((json.dumps({
                'chunk-stream': None
            }), "\n"))

        args = [iter(msg)] * (max_chunk - 1)
        for m in map(''.join, itertools.zip_longest(*args, fillvalue='')):
            yield ''.join(itertools.chain(m, "\n"))
        yield "\n"


def create_server(addr, dbname, *, sync=True):
    from . import server
    db = setup_database(dbname, sync=sync)
    s = server.Server(db)

    (typ, a) = parse_address(addr)
    if typ == ADDR_TYPE_UNIX:
        s.start_unix_server(*a)
    else:
        s.start_tcp_server(*a)

    return s


def create_client(addr):
    from . import client
    c = client.Client()

    (typ, a) = parse_address(addr)
    if typ == ADDR_TYPE_UNIX:
        c.connect_unix(*a)
    else:
        c.connect_tcp(*a)

    return c