import os
import argparse
import subprocess

from . import script_helpers
from .. import ImageFileCollection


def construct_parser():
    parser = argparse.ArgumentParser()

    source_root_help = ('All directories below this one that '
                        'contain images will be processed')
    parser.add_argument('source_root',
                        help=source_root_help,
                        nargs=1)

    group = parser.add_mutually_exclusive_group(required=True)
    dest_root_help = ('If set, image directories below ``source-root`` '
                      'will be copied into this directory tree. Only '
                      'directories that contain image files will be copied; '
                      'any intermediary directories required to contain '
                      'directories that contain images will also be created.')
    group.add_argument('--dest-root',
                       help=dest_root_help,
                       nargs=1)

    group.add_argument('--overwrite-source',
                       help=('This flag must be used to overwrite images in '
                             'the course directory.'),
                       action='store_true'
                       )

    parser.add_argument('--scripts-only',
                        help=('This script will write a single shell script '
                              'with the name provided in this option. No '
                              'images will be modified or directories '
                              'created, but the script can be run to do '
                              'those things.'),
                        action='store_true')

    parser.add_argument('-r', '--run-only',
                        help=('Select which scripts you want to run. This can '
                              'be any combination of [p]atch, [a]strometry '
                              'and [t]riage.'),
                        choices='atp')

    object_list_help = ('Path to file containing list (and optionally '
                        'coordinates of) objects that might be in these files.'
                        ' If not provided it defaults to looking for a file '
                        'called obsinfo.txt in the directory being processed')
    parser.add_argument('-o', '--object-list',
                        help=object_list_help,
                        default=None)

    script_helpers.add_console_output_args(parser)
    script_helpers.add_debug(parser)
    parser.add_argument('--quiet-log',
                        help=('Log only warnings (or worse) to '
                              'FILES AND CONSOLE while running scripts'),
                        action='store_true')

    return parser


def construct_command(script_name, source, destination,
                      common_arguments, additional_args=None):
    command = [script_name]
    command.extend(common_arguments)
    command.extend(['--destination-dir', destination])
    if additional_args:
        command.extend(additional_args)
    command.extend([source])
    command = [arg for arg in command if arg]
    return command


def main(arglist=None):
    """See script_helpers._main_function_docstring for actual documentation
    """
    parser = construct_parser()

    args = parser.parse_args(arglist)

    common_args = []

    verbose = '-v' if not args.quiet_log else ''
    quiet_console = '--quiet-console' if args.quiet_console else ''
    silent_console = '--silent-console' if args.silent_console else ''
    common_args.extend([verbose, quiet_console, silent_console])

    object_list_option = []
    if args.object_list is not None:
        object_list_option = ['--object-list', args.object_list]

    source_root = args.source_root[0]
    dest_root = args.dest_root or [source_root]
    dest_root = dest_root[0]

    # check that source and destination roots are not same unless user has
    # explicitly requested overwrite
    if (dest_root == source_root) & (not args.overwrite_source):
        raise RuntimeError('Will not overwrite source unless you explicitly '
                           'use the option --overwrite-source')

    SEP_REPEAT = 20
    separator_format = '#' * SEP_REPEAT + ' {} ' + '#' * SEP_REPEAT

    SCRIPT_NAME = 'header_process_script.sh'

    scripts_to_run = args.run_only or 'pat'
    patch = 'p' in scripts_to_run
    astrometry = 'a' in scripts_to_run
    triage = 't' in scripts_to_run

    for root, dirs, files in os.walk(source_root):

        if not files:
            continue

        # I should probably make sure there are fits files in here.
        # Not going to...

        # Oh fine, I will test.
        fits_collection = ImageFileCollection(root)
        if not fits_collection.files:
            continue

        source_rel_to_root = os.path.relpath(root, source_root)
        destination = os.path.join(dest_root, source_rel_to_root)

        # Construct strings that will be used to actually do the processing
        make_destination = ['mkdir', '-p', destination]

        run_patch = construct_command('run_patch.py', root, destination,
                                      common_args,
                                      additional_args=object_list_option)
        if not patch:
            run_patch = ''

        # NOTE: after header patching all other scripts should use as their
        # input the directory that was the destination for run_patch if
        # run_patch was executed

        if patch:
            source_for_rest = destination
        else:
            source_for_rest = root

        run_astrometry = construct_command('run_astrometry.py',
                                           source_for_rest,
                                           destination, common_args)
        if not astrometry:
            run_astrometry = ''

        run_triage = construct_command('run_triage.py', source_for_rest,
                                       destination, common_args)

        if not triage:
            run_triage = ''

        cmd_start_str = 'START commands for {}'.format(root)
        cmd_list = [separator_format.format(cmd_start_str)]
        for cmd in [make_destination, run_patch, run_astrometry, run_triage]:
            cmd_list.append(' '.join(cmd))
        end_str = separator_format.format('END commands for {}'.format(root))
        cmd_list.append(end_str)
        cmd_list = '\n'.join(cmd_list) + '\n'*5
        with open(SCRIPT_NAME, mode='a') as f:
            f.write(cmd_list)

        if not args.scripts_only:
            subprocess.call(make_destination)
            script_path = os.path.join(destination, SCRIPT_NAME)
            with open(script_path, 'wb') as script_to_reproduce_this:
                script_to_reproduce_this.write(cmd_list)
            if patch:
                subprocess.call(run_patch)
            if astrometry:
                subprocess.call(run_astrometry)
            if triage:
                subprocess.call(run_triage)

main.__doc__ = script_helpers._main_function_docstring(__name__)
