"""
    Per-directory gallery state
"""

import filesystem, image, html

from utils import lazy_load

class Folder (filesyste.Directory) :
    """
        A Folder is a filesystem Directory that contains any number of other Folders and Images.
    """

    def __init__ (self, node) :
        super(Folder, self).__init__(node)

        # info
        self.title = None
        self.description = None

    @lazy_load
    def preview_dir (self) :
        """
            Load and return the Directory for previews
        """
        
        return self.subdir(self.config.preview_dir, create=True)
    
    @lazy_load
    def thumb_dir (self) :
        """
            Load and return the Directory for thumbs
        """
        
        return self.subdir(self.config.thumb_dir, create=True)
   
    @lazy_load_iter
    def subnodes (self) :
        """
            Load and return an ordered list of child-Nodes
        """

        return super(Folder, self).subnodes(skip_dotfiles=True, sorted=True)
    
    @lazy_load_iter
    def subfolders (self) :
        """
            Load and return an ordered list of sub-Folders
        """

        return (Folder(node) for node in self.subnodes if isinstance(node, filesystem.Directory))

    @lazy_load_iter
    def images (self) :
        """
            Load and return an ordered/linked list of sub-Images
        """

        prev = None

        for node in self.subnodes :
            # skip non-relevant ones
            # XXX: node should need to be a File
            if not isinstance(node, filesystem.File) or not self.config.is_image(node) :
                continue
            
            # create new
            img = image.Image(node, prev)

            # link up
            if prev :
                prev.next = img

                # yield the linked-up prev
                yield prev
            
            # continue
            prev = img
        
        # and the last one
        if prev :
            yield prev

    @property
    def page_count (self) :
        """
            Returns the number of pages needed to show this folder's images
        """

        return math.ceil(len(self.images) / float(self.config.images_per_page))

    def images_for_page (self, page) :
        """
            Returns the list of Images to be displayed for the given page, if any
        """
        
        # offset to first image
        offset = page * self.config.images_per_page
        
        # slice
        return self.images[offset : offset + self.config.images_per_page]

    def html_file (self, page=0) :
        """
            Returns the File representing the .html for the given page
        """
        
        if page :
            return self.subfile("index_%d.html" % page)
        
        else :
            return self.subfile("index.html")
    
    def index (self) :
        """
            Recursively index this Folder, yielding a series of all Folder objects inside.

            XXX: not used
        """
        
        # and subfolders
        for subfolder in self.subfolders :
            yield subfolder

            for item in subfolder.index_subfolders() :
                yield item