# Source code for script.setup

    """Setup, initialization, and clean-up functions

    Functions can be used in Python scripts to setup a GRASS environment
    and session without using grassXY.

    Usage::

        import os
        import sys
        import subprocess

        # define GRASS Database
        # add your path to grassdata (GRASS GIS database) directory
        gisdb = os.path.join(os.path.expanduser("~"), "grassdata")
        # the following path is the default path on MS Windows
        # gisdb = os.path.join(os.path.expanduser("~"), "Documents/grassdata")

        # specify (existing) Location and Mapset
        location = "nc_spm_08"
        mapset = "user1"

        # path to the GRASS GIS launch script
        # we assume that the GRASS GIS start script is available and on PATH
        # query GRASS itself for its GISBASE
        # (with fixes for specific platforms)
        # needs to be edited by the user
        grass7bin = 'grass79'
        if sys.platform.startswith('win'):
            # MS Windows
            grass7bin = r'C:\OSGeo4W\bin\grass79.bat'
            # uncomment when using standalone WinGRASS installer
            # grass7bin = r'C:\Program Files (x86)\GRASS GIS 7.9.0\grass79.bat'
            # this can be avoided if GRASS executable is added to PATH
        elif sys.platform == 'darwin':
            # Mac OS X
            # TODO: this have to be checked, maybe unix way is good enough
            grass7bin = '/Applications/GRASS/GRASS-7.9.app/'

        # query GRASS GIS itself for its GISBASE
        startcmd = [grass7bin, '--config', 'path']
        try:
            p = subprocess.Popen(startcmd, shell=False,
                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
            out, err = p.communicate()
        except OSError as error:
            sys.exit("ERROR: Cannot find GRASS GIS start script"
                     " {cmd}: {error}".format(cmd=startcmd[0], error=error))
        if p.returncode != 0:
            sys.exit("ERROR: Issues running GRASS GIS start script"
                     " {cmd}: {error}"
                     .format(cmd=' '.join(startcmd), error=err))
        gisbase = out.strip(os.linesep)

        # set GISBASE environment variable
        os.environ['GISBASE'] = gisbase

        # define GRASS-Python environment
        grass_pydir = os.path.join(gisbase, "etc", "python")
        sys.path.append(grass_pydir)

        # import (some) GRASS Python bindings
        import grass.script as gs
        import grass.script.setup as gsetup

        # launch session
        rcfile = gsetup.init(gisbase, gisdb, location, mapset)

        # example calls
        gs.message('Current GRASS GIS 7 environment:')
        print(gs.gisenv())

        gs.message('Available raster maps:')
        for rast in gs.list_strings(type='raster'):
            print(rast)

        gs.message('Available vector maps:')
        for vect in gs.list_strings(type='vector'):
            print(vect)

        # clean up at the end
        gsetup.cleanup()

    (C) 2010-2020 by the GRASS Development Team
    This program is free software under the GNU General Public
    License (>=v2). Read the file COPYING that comes with GRASS
    for details.

    @author Martin Landa <landa.martin gmail.com>
    @author Vaclav Petras <wenzeslaus gmail.com>
    @author Markus Metz
    """

    # TODO: this should share code from lib/init/grass.py
    # perhaps grass.py can import without much trouble once GISBASE
    # is known, this would allow moving things from there, here
    # then this could even do locking

    import os
    import sys
    import tempfile as tmpfile

    windows = sys.platform == 'win32'

    def write_gisrc(dbase, location, mapset):
        """Write the ``gisrc`` file and return its path."""
        gisrc = tmpfile.mktemp()
        with open(gisrc, 'w') as rc:
            rc.write("GISDBASE: %s\n" % dbase)
            rc.write("LOCATION_NAME: %s\n" % location)
            rc.write("MAPSET: %s\n" % mapset)
        return gisrc

    def set_gui_path():
        """Insert wxPython GRASS path to sys.path."""
        gui_path = os.path.join(os.environ['GISBASE'], 'gui', 'wxpython')
        if gui_path and gui_path not in sys.path:
            sys.path.insert(0, gui_path)

    def init(gisbase, dbase='', location='demolocation', mapset='PERMANENT'):
        """Initialize system variables to run GRASS modules

        This function is for running GRASS GIS without starting it with the
        standard script grassXY. No GRASS modules shall be called before
        call of this function but any module or user script can be called
        afterwards because a GRASS session has been set up. GRASS Python
        libraries are usable as well in general but the ones using C
        libraries through ``ctypes`` are not (which is caused by library
        path not being updated for the current process which is a common
        operating system limitation).

        To create a GRASS session a ``gisrc`` file is created.
        Caller is responsible for deleting the ``gisrc`` file.

        Basic usage::

            # ... setup GISBASE and PYTHON path before import
            import grass.script as gs
            gisrc = gs.setup.init("/usr/bin/grass7",
                                  "/home/john/grassdata",
                                  "nc_spm_08", "user1")
            # ... use GRASS modules here
            # end the session
            gs.setup.finish()

        :param gisbase: path to GRASS installation
        :param dbase: path to GRASS database (default: '')
        :param location: location name (default: 'demolocation')
        :param mapset: mapset within given location (default: 'PERMANENT')

        :returns: path to ``gisrc`` file (to be deleted later)
        """
        # Set GISBASE
        os.environ['GISBASE'] = gisbase
        mswin = sys.platform.startswith('win')
        # define PATH
        os.environ['PATH'] += os.pathsep + os.path.join(gisbase, 'bin')
        os.environ['PATH'] += os.pathsep + os.path.join(gisbase, 'scripts')
        if mswin:  # added for winGRASS
            os.environ['PATH'] += os.pathsep + os.path.join(gisbase, 'extrabin')

        # add addons to the PATH
        # copied and simplified from lib/init/grass.py
        if mswin:
            config_dirname = "GRASS7"
            config_dir = os.path.join(os.getenv('APPDATA'), config_dirname)
        else:
            config_dirname = ".grass7"
            config_dir = os.path.join(os.getenv('HOME'), config_dirname)
        addon_base = os.path.join(config_dir, 'addons')
        os.environ['GRASS_ADDON_BASE'] = addon_base
        if not mswin:
            os.environ['PATH'] += os.pathsep + os.path.join(addon_base, 'scripts')
        os.environ['PATH'] += os.pathsep + os.path.join(addon_base, 'bin')

        # define LD_LIBRARY_PATH
        if 'LD_LIBRARY_PATH' not in os.environ:
            os.environ['LD_LIBRARY_PATH'] = ''
        os.environ['LD_LIBRARY_PATH'] += os.pathsep + os.path.join(gisbase, 'lib')

        # TODO: lock the mapset?
        os.environ['GIS_LOCK'] = str(os.getpid())

        # Set GRASS_PYTHON and PYTHONPATH to find GRASS Python modules
        if not os.getenv('GRASS_PYTHON'):
            if sys.platform == 'win32':
                os.environ['GRASS_PYTHON'] = "python3.exe"
            else:
                os.environ['GRASS_PYTHON'] = "python3"

        path = os.getenv('PYTHONPATH')
        etcpy = os.path.join(gisbase, 'etc', 'python')
        if path:
            path = etcpy + os.pathsep + path
        else:
            path = etcpy
        os.environ['PYTHONPATH'] = path

        # TODO: isn't this contra-productive? may fail soon since we cannot
        # write to the installation (applies also to defaults for Location
        # and mapset) I don't see what would be the use case here.
        if not dbase:
            dbase = gisbase

        os.environ['GISRC'] = write_gisrc(dbase, location, mapset)
        return os.environ['GISRC']

    # clean-up functions when terminating a GRASS session
    # these fns can only be called within a valid GRASS session
    def clean_default_db():
        # clean the default db if it is sqlite
        from grass.script import db as gdb
        from grass.script import core as gcore

        conn = gdb.db_connection()
        if conn and conn['driver'] == 'sqlite':
            # check if db exists
            gisenv = gcore.gisenv()
            database = conn['database']
            database = database.replace('$GISDBASE', gisenv['GISDBASE'])
            database = database.replace('$LOCATION_NAME', gisenv['LOCATION_NAME'])
            database = database.replace('$MAPSET', gisenv['MAPSET'])
            if os.path.exists(database):
                gcore.message(_("Cleaning up default sqlite database ..."))
                gcore.start_command('db.execute', sql = 'VACUUM')
                # give it some time to start
                import time
                time.sleep(0.1)

    def call(cmd, **kwargs):
        import subprocess
        """Wrapper for subprocess.call to deal with platform-specific issues"""
        if windows:
            kwargs['shell'] = True
        return subprocess.call(cmd, **kwargs)

    def clean_temp():
        from grass.script import core as gcore

        gcore.message(_("Cleaning up temporary files..."))
        nul = open(os.devnull, 'w')
        gisbase = os.environ['GISBASE']
        call([os.path.join(gisbase, "etc", "clean_temp")], stdout=nul)
        nul.close()

    def finish():
        """Terminate the GRASS session and clean up

        GRASS commands can no longer be used after this function has been
        called

        Basic usage::
            import grass.script as gs

            gs.setup.cleanup()
        """

        clean_default_db()
        clean_temp()
        # TODO: unlock the mapset?
        # unset the GISRC and delete the file
        from grass.script import utils as gutils
        gutils.try_remove(os.environ['GISRC'])
        os.environ.pop('GISRC')
        # remove gislock env var (not the gislock itself
        os.environ.pop('GIS_LOCK')

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