# CSSPrefixer
# Copyright 2010-2012 Greg V. <floatboth@me.com>

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

# http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from rules import prefixRegex, rules as tr_rules
import cssutils
import re


keyframesRegex = re.compile(r'@keyframes\s?\w+\s?{(.*)}')
blockRegex = re.compile(r'\w+\s?\{(.*)\}')


def magic(ruleset, debug, minify, filt, parser):
    if isinstance(ruleset, cssutils.css.CSSUnknownRule):
        if ruleset.cssText.startswith('@keyframes'):
            inner = parser.parseString(keyframesRegex.split(ruleset.cssText.replace('\n', ''))[1])
            # BUG: doesn't work when minified
            s = '' if minify else '\n'
            return '@-webkit-keyframes {' + s + \
            ''.join([magic(rs, debug, minify, ['webkit'], parser) for rs in inner]) \
            + '}' + s + '@-moz-keyframes {' + s + \
            ''.join([magic(rs, debug, minify, ['moz'], parser) for rs in inner]) \
            + '}' + s + ruleset.cssText
        elif ruleset.cssText.startswith('from') or ruleset.cssText.startswith('to'):
            return ''.join([magic(rs, debug, minify, filt, parser)
                for rs in parser.parseString(blockRegex.sub(r'\1', ruleset.cssText.replace('\n', ''))[1])])
        else:
            return
    elif hasattr(ruleset, 'style'): # Comments don't
        ruleSet = set()
        rules = list()
        children = list(ruleset.style.children())
        ruleset.style = cssutils.css.CSSStyleDeclaration() # clear out the styles that were there
        for rule in children:
            if not hasattr(rule, 'name'): # comments don't have name
                rules.append(rule)
                continue
            name = prefixRegex.sub('', rule.name)
            if name in tr_rules:
                rule.name = name
            if rule.cssText in ruleSet:
                continue
            ruleSet.add(rule.cssText)
            rules.append(rule)

        ruleset.style.seq._readonly = False
        for rule in rules:
            if not hasattr(rule, 'name'):
                ruleset.style.seq.append(rule, 'Comment')
                continue
            processor = None
            try: # try except so if anything goes wrong we don't lose the original property
                if rule.name in tr_rules:
                    processor = tr_rules[rule.name](rule)
                    [ruleset.style.seq.append(prop, 'Property') for prop in processor.get_prefixed_props(filt) if prop]
                # always add the original rule
                if processor and hasattr(processor, 'get_base_prop'):
                    ruleset.style.seq.append(processor.get_base_prop(), 'Property')
                else:
                    ruleset.style.seq.append(rule, 'Property')
            except:
                if debug:
                    print 'warning with ' + str(rule)
                ruleset.style.seq.append(rule, 'Property')
        ruleset.style.seq._readonly = True
    elif hasattr(ruleset, 'cssRules'):
        for subruleset in ruleset:
            magic(subruleset, debug, minify, filt, parser)
    cssText = ruleset.cssText
    if not cssText: # blank rules return None so return an empty string
        return
    if minify or not hasattr(ruleset, 'style'):
        return cssText
    return cssText + '\n'


def process(string, debug = False, minify = False, filt = ['webkit', 'moz', 'o', 'ms'], **prefs):
    parser = cssutils.CSSParser(loglevel = 'CRITICAL')
    if minify:
        cssutils.ser.prefs.useMinified()
    else:
        cssutils.ser.prefs.useDefaults()

    # use the passed in prefs
    for key, value in prefs.iteritems():
        if hasattr(cssutils.ser.prefs, key):
            cssutils.ser.prefs.__dict__[key] = value

    results = []
    sheet = parser.parseString(string)
    for ruleset in sheet.cssRules:
        cssText = magic(ruleset, debug, minify, filt, parser)
        if cssText:
            results.append(cssText)

    # format with newlines based on minify
    joinStr = '' if minify else '\n'

    # Not using sheet.cssText - it's buggy:
    # it skips some prefixed properties.
    return joinStr.join(results).rstrip()

__all__ = ['process']