#!/usr/bin/env python3
#
# Copyright (c) 2020 The Khronos Group Inc.
#
# SPDX-License-Identifier: Apache-2.0

# Build a spec with requested extension sets and options.
#
# Usage: makeSpec script-options make-options
# Script options are parsed by this script before invoking 'make':
#   -genpath path - directory for generated files and outputs
#   -spec core - make a spec with no extensions (default)
#   -spec khr - make a spec with all KHR extensions
#   -spec all - make a spec with all registered extensions
#   -ext name - add specified extension and its dependencies
#   -clean - clean generated files before building
#   -v - verbose, print actions before executing  them
#   -n - dry-run, print actions instead of executing them
# make-options - all other options are passed to 'make', including
# requested build targets

import argparse, copy, io, os, re, string, subprocess, sys

def execute(args, results):
    if results.verbose or results.dryrun:
        print("'" + "' '".join(args) + "'")
    if not results.dryrun:
        subprocess.check_call(args)

if __name__ == '__main__':
    parser = argparse.ArgumentParser()

    parser.add_argument('-clean', action='store_true',
                        help='Clean generated files before building')
    parser.add_argument('-extension', action='append',
                        default=[],
                        help='Specify a required extension or extensions to add to targets')
    parser.add_argument('-genpath', action='store',
                        default='gen',
                        help='Path to directory containing generated files')
    parser.add_argument('-spec', action='store',
                        choices=[ 'core', 'khr', 'all' ],
                        default='core',
                        help='Type of spec to generate')
    parser.add_argument('-n', action='store_true', dest='dryrun',
                        help='Only prints actions, do not execute them')
    parser.add_argument('-v', action='store_true', dest='verbose',
                        help='Print actions before executing them')

    (results, options) = parser.parse_known_args()

    # Ensure genpath is an absolute path, not relative
    if results.genpath[0] != '/':
        results.genpath = os.getcwd() + '/' + results.genpath

    # Ensure extDependency.py exists and is up to date before importing it
    execute(['make', 'GENERATED=' + results.genpath, 'extDependency'], results)

    # Look for extDependency.py in the specified directory and import it
    sys.path.insert(0, results.genpath)
    from extDependency import extensions, allExts, khrExts

    # List of extensions to build with from the requested -spec
    # Also construct a spec title
    if results.spec == 'core':
        title = ''
        exts = set()
    if results.spec == 'khr':
        title = 'with all KHR extensions'
        exts = set(khrExts)
    elif results.spec == 'all':
        title = 'with all registered extensions'
        exts = set(allExts)

    # List of explicitly requested extension and all its dependencies
    extraexts = set()
    for name in results.extension:
        if name in extensions:
            extraexts.add(name)
            extraexts.update(extensions[name])
        else:
            print('ERROR: unknown extension', name, file=sys.stderr)
            sys.exit(1)

    # See if any explicitly requested extensions aren't implicitly requested
    # Add any such extensions to the spec title
    extraexts -= exts
    if len(extraexts) > 0:
        exts.update(extraexts)
        if title != '':
            title += ' and ' + ', '.join(sorted(extraexts))
        else:
            title += 'with ' + ', '.join(sorted(extraexts))

    if title != '':
        title = '(' + title + ')'

    # Finally, actually invoke make as needed for the targets
    args = [ 'make', 'GENERATED=' + results.genpath ]

    if results.clean:
        execute(args + ['clean'], results)

    # The actual target
    if len(exts) > 0:
        args.append('EXTENSIONS={}'.format(' '.join(sorted(exts))))
    args.append('APITITLE={}'.format(title))
    args += options

    execute(args, results)