# -*- coding: utf-8 -*-

import os

try:
    import urlparse
except ImportError:
    import urllib.parse as urlparse

try:
    from django import VERSION as DJANGO_VERSION
except ImportError:
    DJANGO_VERSION = None


# Register database schemes in URLs.
urlparse.uses_netloc.append("postgres")
urlparse.uses_netloc.append("postgresql")
urlparse.uses_netloc.append("pgsql")
urlparse.uses_netloc.append("postgis")
urlparse.uses_netloc.append("mysql")
urlparse.uses_netloc.append("mysql2")
urlparse.uses_netloc.append("mysqlgis")
urlparse.uses_netloc.append("mysql-connector")
urlparse.uses_netloc.append("mssql")
urlparse.uses_netloc.append("spatialite")
urlparse.uses_netloc.append("sqlite")
urlparse.uses_netloc.append("oracle")
urlparse.uses_netloc.append("oraclegis")
urlparse.uses_netloc.append("redshift")

DEFAULT_ENV = "DATABASE_URL"

SCHEMES = {
    "postgis": "django.contrib.gis.db.backends.postgis",
    "mysql": "django.db.backends.mysql",
    "mysql2": "django.db.backends.mysql",
    "mysqlgis": "django.contrib.gis.db.backends.mysql",
    "mysql-connector": "mysql.connector.django",
    "mssql": "sql_server.pyodbc",
    "spatialite": "django.contrib.gis.db.backends.spatialite",
    "sqlite": "django.db.backends.sqlite3",
    "oracle": "django.db.backends.oracle",
    "oraclegis": "django.contrib.gis.db.backends.oracle",
    "redshift": "django_redshift_backend",
}

# https://docs.djangoproject.com/en/2.0/releases/2.0/#id1
if DJANGO_VERSION and DJANGO_VERSION < (2, 0):
    SCHEMES["postgres"] = "django.db.backends.postgresql_psycopg2"
    SCHEMES["postgresql"] = "django.db.backends.postgresql_psycopg2"
    SCHEMES["pgsql"] = "django.db.backends.postgresql_psycopg2"
else:
    SCHEMES["postgres"] = "django.db.backends.postgresql"
    SCHEMES["postgresql"] = "django.db.backends.postgresql"
    SCHEMES["pgsql"] = "django.db.backends.postgresql"


def config(
    env=DEFAULT_ENV, default=None, engine=None, conn_max_age=0, ssl_require=False
):
    """Returns configured DATABASE dictionary from DATABASE_URL."""

    config = {}

    s = os.environ.get(env, default)

    if s:
        config = parse(s, engine, conn_max_age, ssl_require)

    return config


def parse(url, engine=None, conn_max_age=0, ssl_require=False):
    """Parses a database URL."""

    if url == "sqlite://:memory:":
        # this is a special case, because if we pass this URL into
        # urlparse, urlparse will choke trying to interpret "memory"
        # as a port number
        return {"ENGINE": SCHEMES["sqlite"], "NAME": ":memory:"}
        # note: no other settings are required for sqlite

    # otherwise parse the url as normal
    config = {}

    url = urlparse.urlparse(url)

    # Split query strings from path.
    path = url.path[1:]
    if "?" in path and not url.query:
        path, query = path.split("?", 2)
    else:
        path, query = path, url.query
    query = urlparse.parse_qs(query)

    # If we are using sqlite and we have no path, then assume we
    # want an in-memory database (this is the behaviour of sqlalchemy)
    if url.scheme == "sqlite" and path == "":
        path = ":memory:"

    # Handle postgres percent-encoded paths.
    hostname = url.hostname or ""
    if "%2f" in hostname.lower():
        # Switch to url.netloc to avoid lower cased paths
        hostname = url.netloc
        if "@" in hostname:
            hostname = hostname.rsplit("@", 1)[1]
        if ":" in hostname:
            hostname = hostname.split(":", 1)[0]
        hostname = hostname.replace("%2f", "/").replace("%2F", "/")

    # Lookup specified engine.
    engine = SCHEMES[url.scheme] if engine is None else engine

    port = (
        str(url.port)
        if url.port and engine in [SCHEMES["oracle"], SCHEMES["mssql"]]
        else url.port
    )

    # Update with environment configuration.
    config.update(
        {
            "NAME": urlparse.unquote(path or ""),
            "USER": urlparse.unquote(url.username or ""),
            "PASSWORD": urlparse.unquote(url.password or ""),
            "HOST": hostname,
            "PORT": port or "",
            "CONN_MAX_AGE": conn_max_age,
        }
    )

    # Pass the query string into OPTIONS.
    options = {}
    for key, values in query.items():
        if url.scheme == "mysql" and key == "ssl-ca":
            options["ssl"] = {"ca": values[-1]}
            continue

        options[key] = values[-1]

    if ssl_require:
        options["sslmode"] = "require"

    # Support for Postgres Schema URLs
    if "currentSchema" in options and engine in (
        "django.contrib.gis.db.backends.postgis",
        "django.db.backends.postgresql_psycopg2",
        "django.db.backends.postgresql",
        "django_redshift_backend",
    ):
        options["options"] = "-c search_path={0}".format(options.pop("currentSchema"))

    if options:
        config["OPTIONS"] = options

    if engine:
        config["ENGINE"] = engine

    return config