import logging
from werkzeug.utils import cached_property
from piecrust.data.assetor import Assetor
from piecrust.data.base import MergedMapping
from piecrust.data.linker import PageLinkerData
from piecrust.data.pagedata import PageData
from piecrust.data.paginator import Paginator
from piecrust.data.piecrustdata import PieCrustData
from piecrust.data.providersdata import DataProvidersData
from piecrust.routing import CompositeRouteFunction


logger = logging.getLogger(__name__)


class DataBuildingContext(object):
    def __init__(self, qualified_page, page_num=1):
        self.page = qualified_page
        self.page_num = page_num
        self.pagination_source = None
        self.pagination_filter = None

    @property
    def app(self):
        return self.page.app

    @cached_property
    def uri(self):
        return self.page.getUri(self.page_num)


def build_page_data(ctx):
    app = ctx.app
    page = ctx.page
    pgn_source = ctx.pagination_source or get_default_pagination_source(page)
    first_uri = ctx.page.getUri(1)

    pc_data = PieCrustData()
    config_data = PageData(page, ctx)
    paginator = Paginator(page, pgn_source,
                          page_num=ctx.page_num,
                          pgn_filter=ctx.pagination_filter)
    assetor = Assetor(page, first_uri)
    linker = PageLinkerData(page.source, page.rel_path)
    data = {
            'piecrust': pc_data,
            'page': config_data,
            'assets': assetor,
            'pagination': paginator,
            'family': linker
            }

    for route in app.routes:
        name = route.func_name
        func = data.get(name)
        if func is None:
            func = CompositeRouteFunction()
            func.addFunc(route)
            data[name] = func
        elif isinstance(func, CompositeRouteFunction):
            func.addFunc(route)
        else:
            raise Exception("Route function '%s' collides with an "
                            "existing function or template data." %
                            name)

    #TODO: handle slugified taxonomy terms.

    site_data = app.config.getAll()
    providers_data = DataProvidersData(page)
    data = MergedMapping([data, providers_data, site_data])

    # Do this at the end because we want all the data to be ready to be
    # displayed in the debugger window.
    if (app.config.get('site/show_debug_info') and
            not app.config.get('baker/is_baking')):
        pc_data.enableDebugInfo(page)

    return data


def build_layout_data(page, page_data, contents):
    for name, txt in contents.items():
        if name in page_data:
            logger.warning("Content segment '%s' will hide existing data." %
                           name)
    page_data._prependMapping(contents)


def get_default_pagination_source(page):
    app = page.app
    source_name = page.config.get('source') or page.config.get('blog')
    if source_name is None:
        source_name = app.config.get('site/default_pagination_source')
    if source_name is None:
        blog_names = app.config.get('site/blogs')
        if blog_names is not None:
            source_name = blog_names[0]
        else:
            source_name = app.sources[0].name
    source = app.getSource(source_name)
    return source