#!/usr/bin/python

"""
Automatic dependency generator for Node.js libraries.

Parsed from package.json.  See `man npm-json` for details.
"""

# Copyright 2012 T.C. Hollingsworth <tchollingsworth@gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.

from __future__ import unicode_literals
import json
import re
import sys

RE_VERSION = re.compile(r'\s*v?([<>=~]{0,2})\s*([0-9][0-9\.\-]*)\s*')

def main():
    #npm2rpm uses functions here to write BuildRequires so don't print anything
    #until the very end
    deps = []

    #it's highly unlikely that we'll ever get more than one file but we handle
    #this like all RPM automatic dependency generation scripts anyway
    paths = [path.rstrip() for path in sys.stdin.readlines()]

    for path in paths:
        if path.endswith('package.json'):
            fh = open(path)
            metadata = json.load(fh)
            fh.close()

            #write out the node.js interpreter dependency
            req = 'nodejs(engine)'
            
            if 'engines' in metadata and 'node' in metadata['engines']:
                deps += process_dep(req, metadata['engines']['node'])
            else:
                deps.append(req)

            if 'dependencies' in metadata:
                for name, version in metadata['dependencies'].iteritems():
                    req = 'npm(' + name + ')'
                    deps += process_dep(req, version)

    print '\n'.join(deps)

def process_dep(req, version):
    """Converts an individual npm dependency into RPM dependencies"""
    
    deps = []
    
    #there's no way RPM can do anything like an OR dependency
    if '||' in version:
        sys.stderr.write("WARNING: The {0} dependency contains an ".format(req) +
            "OR (||) dependency: '{0}.\nPlease manually include ".format(version) +
            "a versioned dependency in your spec file if necessary")
        deps.append(req)
            
    elif ' - ' in version:
        gt, lt = version.split(' - ')
        deps.append(req + ' >= ' + gt)
        deps.append(req + ' <= ' + lt)
        
    else:
        m = re.match(RE_VERSION, version)

        if m:
            deps += convert_dep(req, m.group(1), m.group(2))

            #There could be up to two versions here (e.g.">1.0 <3.1")
            if len(version) > m.end():
                m = re.match(RE_VERSION, version[m.end():])

                if m:
                    deps += convert_dep(req, m.group(1), m.group(2))
        else:
            deps.append(req)

    return deps
            
def convert_dep(req, operator, version):
    """Converts one of the two possibly listed versions into an RPM dependency"""
    
    deps = []

    #any version will do
    if not version or version == '*':
        deps.append(req)

    #any prefix but ~ makes things dead simple
    elif operator in ['>', '<', '<=', '>=', '=']:
        deps.append(' '.join([req, operator, version]))

    #oh boy, here we go...
    else:
        #split the dotted portions into a list (handling trailing dots properly)
        parts = [part if part else 'x' for part in version.split('.')]
        parts = [int(part) if part != 'x' and not '-' in part
                                                    else part for part in parts]

        # 1 or 1.x or 1.x.x or ~1
        if len(parts) == 1 or parts[1] == 'x':
            if parts[0] != 0:
                deps.append('{0} >= {1}'.format(req, parts[0]))
            deps.append('{0} < {1}'.format(req, parts[0]+1))

        # 1.2.3 or 1.2.3-4 or 1.2.x or ~1.2.3 or 1.2
        elif len(parts) == 3 or operator != '~':
            # 1.2.x or 1.2
            if len(parts) == 2 or parts[2] == 'x':
                deps.append('{0} >= {1}.{2}'.format(req, parts[0], parts[1]))
                deps.append('{0} < {1}.{2}'.format(req, parts[0], parts[1]+1))
            # ~1.2.3
            elif operator == '~':
                deps.append('{0} >= {1}'.format(req, version))
                deps.append('{0} < {1}.{2}'.format(req, parts[0], parts[1]+1))
            # 1.2.3 or 1.2.3-4
            else:
                deps.append('{0} = {1}'.format(req, version))

        # ~1.2
        else:
            deps.append('{0} >= {1}'.format(req, version))
            deps.append('{0} < {1}'.format(req, parts[0]+1))

    return deps
            
if __name__ == '__main__':
    main()