# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
# vim: set filetype=python:
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# Templates implementing some generic checks.

# Helper to display "checking" messages
#   @checking('for foo')
#   def foo():
#       return 'foo'
# is equivalent to:
#   def foo():
#       sys.stdout.write('checking for foo... ')
#       ret = foo
#       sys.stdout.write(ret + '\n')
#       return ret
# This can be combined with e.g. @depends:
#   @depends(some_option)
#   @checking('for something')
#   def check(value):
#       ...
@template
def checking(what):
    def decorator(func):
        @advanced
        def wrapped(*args, **kwargs):
            import sys
            print('checking', what, end='... ')
            sys.stdout.flush()
            ret = func(*args, **kwargs)
            if ret is True:
                print('yes')
            elif ret is False:
                print('no')
            else:
                print(ret)
            sys.stdout.flush()
            return ret
        return wrapped
    return decorator


# Template to check for programs in $PATH.
#   check('PROG', ('a', 'b'))
# will look for 'a' or 'b' in $PATH, and set_config PROG to the one
# it can find. If PROG is already set from the environment or command line,
# use that value instead.
@template
def check_prog(var, progs, allow_missing=False):
    option(env=var, nargs=1, help=var)

    not_found = 'not found'
    progs = list(progs)

    @depends(var)
    @checking('for %s' % var.lower())
    def check(value):
        if value:
            progs[:] = value
        for prog in progs:
            result = find_program(prog)
            if result:
                return result
        return not_found

    @depends(check)
    @advanced
    def postcheck(value):
        set_config(var, ':' if value is not_found else value)
        if not value and not allow_missing:
            from mozbuild.shellutil import quote
            error('Cannot find %s (tried: %s)'
                  % (var.lower(), ', '.join(quote(p) for p in progs)))

    return check