#!/usr/bin/env python
# -*- coding: utf-8 -*-
import os
import shutil
import re
import argparse
import pandoc
import cli
from tempfile import NamedTemporaryFile
from jinja2 import Environment, FileSystemLoader


class Templater:
    ''' Pandoc Template generator.
    Creates a template suitible for passing to pandoc for html generation.

    The most prominent feature is adding the custom table of contents
    navigator that navigates accross muliple html pages.

    The generator references a jinja2 template file called html5.template
    located either in the directory 'templates' under the source path,
    or in the directory passed as an option.
    '''
    def __init__(self, path):
        self.templates_path = path
        self.j2 = Environment(loader=FileSystemLoader(self.templates_path),
                              line_statement_prefix='#')

    def page_template(self, doc, page):
        '''
        Returns a new page template for use by pandoc.

        Arguments:
        - doc: Panfry.Document.
        - page: Panfry.Page from Panfry.Document to generate template for.
        '''
        options = dict(toc=doc.toc_links)
        options['page'] = unicode(page.htmlfile, "utf8")
        options['pdf'] = unicode(doc.pdf_filename)
        options['prev'] = u''
        options['next'] = u''
        prevpage = doc.prev_page(page)
        nextpage = doc.next_page(page)
        if prevpage:
            options['prev'] = unicode(prevpage.htmlfile, "utf8")
        if nextpage:
            options['next'] = unicode(nextpage.htmlfile, "utf8")

        template = self.j2.get_template('html5.template')

        return template.render(options=options).encode('utf-8')


class Page:
    '''
    Represents single source file.
    '''
    def __init__(self, filename, source):
        self.filename = filename
        self.source = source

    @property
    def title(self):
        '''
        Returns a tuple containing a string representing the page title
        and an integer representing the level in the document outline
        hierarchy.

        The level is preserved so that page titles can be properly
        positioned (indented) in the table of contents.

        If the page has a pandoc title block, the title is retreived
        from there and returned with a level of 1

        If a title block is not found, the first heading is returned
        with the corrisponding heading level.

        Finally, if no title block or headings are found in the page,
        the filename is returned as the title with underscores changed
        to spaces.
        '''
        title = ''
        for line in get_lines(self.source):
            if line.startswith('% '):
                title = line.split(' ', 1)[1].strip()
                if '(' and ')' in line:
                    num = line.split('(')[1][0]
                    return 'man(%s) %s' % (num, title.split('(')[0].strip())
                else:
                    return (title, 1)
            if re.match('[=]{2}', line):
                return (title, 1)
            if re.match('[-]{2}', line):
                return (title, 2)
            if re.match('#+.+[A-z|0-9]', line):
                level = len(re.match('#+', line).group())
                return (line.split(' ', 1)[1].strip(), level)
            title = line.strip()

        title = self.filename.replace('_', ' ')

        return (title, 1)

    @property
    def htmlfile(self):
        return '.'.join(self.filename.split('.')[:-1]) + '.html'


class Document:

    def __init__(self, path):
        self.src_path = path
        self.meta = self.get_meta(path)
        self.pages = self.get_pages(path)

    css_file = 'css/style.css'
    workdir = 'stdocs-work'

    def get_pages(self, path):
        pages = []
        filelist = get_lines(self.meta['TOC'])
        for filename in filelist:
            source = read_file(os.path.join(path, filename))
            if source:
                pages.append(Page(filename, source))
            else:
                print("WARNING: Page: %s not found or is empty." % filename)

        return pages

    def get_meta(self, path):
        metafiles = ['TOC', 'HEADER']
        meta = {}
        for filename in metafiles:
            source = read_file(os.path.join(path, filename))
            if source:
                meta[filename] = source
            else:
                print("!E: %s not found or is empty. Aborting..." % filename)
                exit(1)

        return meta

    def set_templater(self, templater):
        self.templater = templater

    def next_page(self, page):
        try:
            idx = self.pages.index(page)
        except:
            return ''
        if idx >= len(self.pages) - 1:
            return ''
        return self.pages[idx+1]

    def prev_page(self, page):
        try:
            idx = self.pages.index(page)
        except:
            return ''
        if idx == 0:
            return ''
        return self.pages[idx-1]

    @property
    def toc_links(self):
        '''
        Returns a list of dictionaries. Each dictionary element contains
        a page title and the html file name.
        '''
        links = []
        for page in self.pages:
            title, level = page.title
            links.append(dict(link=unicode(page.htmlfile, "utf8"),
                              text=unicode(title, "utf8"),
                              level=level,
                              ))

        return links

    @property
    def pdf_filename(self):
        header = self.meta['HEADER']
        m = re.match('(^%)(.*\n.*)(%*)', header)
        if m:
            title = m.group(2).strip()
            title = re.sub(r'\s+', ' ', title)
            title = re.sub(r'[\n ]', '_', title)
            title = re.sub(r'[:,]', '-', title)
            title = re.sub(r'_+', '_', title)
            title = re.sub(r'-_', '-', title)
            title = re.sub(r'-+', '-', title)
        else:
            title = os.path.split(self.src_path)[1]

        return title + '.pdf'

    def publish_pdf(self, pub_path):
        pdf_path = os.path.join(pub_path, self.pdf_filename)
        src = self.meta['HEADER']
        for page in self.pages:
            src += '\n%s' % page.source

        doc = pandoc.Document()
        doc.markdown = src

        pandoc.set_cwd(os.path.abspath(self.src_path))
        doc.to_file(pdf_path)
        pandoc.set_cwd(None)

        return self.pdf_filename

    def publish_css(self, pub_path):
        src = os.path.join(self.src_path, 'css')
        dst = os.path.join(pub_path, 'css')
        if os.path.isdir(src):
            copy(src, dst)

    def publish_images(self, pub_path):
        src_path = self.src_path
        if os.path.exists(os.path.join(src_path, 'images/html')):
            src = os.path.join(src_path, 'images/html')
        else:
            src = os.path.join(src_path, 'images')

        dst = os.path.join(pub_path, 'images')
        if os.path.exists(src):
            copy(src, dst)

    def publish_html(self, pub_path):
        pandoc.set_cwd(None)
        for page in self.pages:
            print("generating %s..." % page.htmlfile)
            template_file = NamedTemporaryFile(mode='w',
                                               suffix='pf.template',
                                               delete=False)
            template = self.templater.page_template(self, page)
            template_file.write(template)
            template_file.close()
            doc = pandoc.Document()
            doc.add_argument('toc')
            doc.add_argument('template=%s' % template_file.name)
            doc.add_argument('css=%s' % self.css_file)
            doc.markdown = page.source
            content = doc.html
            write_file(os.path.join(pub_path, page.htmlfile),
                       unicode(content, 'utf-8'))

        # If there is not explicit index.html, then link 'index.html'
        # to the toplevel page.
        if not 'index.md' in self.pages:
            src = os.path.join(self.pages[0].htmlfile)
            ref = os.path.join(pub_path, 'index.html')
            os.symlink(src, ref)

        ###### Copy any images to publish directory
        self.publish_css(pub_path)
        self.publish_images(pub_path)


def copy(src, dst, ignore=None):
    if os.path.isdir(src):
        shutil.copytree(src, dst, True, ignore)
    else:
        shutil.copy(src, dst)


def open_file(path, mode='r'):
    if mode == 'w' or os.path.isfile(path):
        return open(path, mode)
    else:
        return None


def write_file(path, content):
    fd = open_file(path, mode='w')
    if fd:
        fd.write(content.encode('utf-8'))
        fd.close()
        return path
    else:
        return None


def read_file(path):
    content = ''
    fd = open_file(path)
    if fd:
        content = fd.read()
        fd.close()
        return content
    else:
        print("Error: could not open %s" % path)
        return content


def read_file_lines(path):
    content = []
    fd = open_file(path)
    if fd:
        content = fd.readlines()
        fd.close()
    return content


def get_lines(content):
    '''
    return list of content split by line.
    Leading/trailing blank lines are not reserved.
    '''
    return content.strip().split('\n')


def init_argparser():
    parser = argparse.ArgumentParser()
    parser.add_argument('src_path', nargs='?',
                        default='.',
                        help='Path of document sources')
    parser.add_argument('pub_path', nargs='?',
                        default='./pub',
                        help='Directory to place output')
    parser.add_argument('-T', '--templates', dest='templates_path',
                        default='',
                        help='Directory to find templates')
    parser.add_argument('-C', '--css', dest='css_file',
                        default='',
                        help='css file for html pages',
                        )
    return parser


def get_env():
    env = cli.init_argparser().parse_args()
    if not os.path.isdir(env.src_path):
        print("%s directory not found. Aborting..." % env.src_path)
        exit(1)

    env.pub_path = os.path.abspath(env.pub_path)

    if not env.templates_path:
        env.templates_path = os.path.join(env.src_path, 'templates')

    if not os.path.isdir(env.templates_path):
        print("No templates path found. Aborting...")
        exit(1)

    return env

if __name__ == "__main__":
    env = get_env()
    if os.path.exists(env.pub_path):
        shutil.rmtree(env.pub_path)
    os.mkdir(env.pub_path)

    document = Document(env.src_path)
    document.set_templater(Templater(env.templates_path))

    ###### Create PDF
    pdffile = document.publish_pdf(env.pub_path)
    print("Wrote PDF: %s" % pdffile)

    ###### Create HTML
    document.publish_html(env.pub_path)

    exit(0)