#!/usr/bin/env python3

import argparse, os
import docutils.core

def basename(fname):
    '''Returns the name of the guide from either its name or its directory'''
    if os.path.isdir(os.path.join('guides',fname)):
        return fname
    elif os.path.isdir(fname):
        return os.path.basename(os.path.abspath(fname))
    else:
        msg = '%s is not a valid directory' % fname
        raise argparse.ArgumentTypeError(msg)

def build_latex(guide):
    '''Builds the LaTeX source for the guide'''
    src_dir = os.path.join('guides',guide)
    tools_dir = 'tools'
    build_dir = os.path.join('build',guide)
    tex_name = guide+'.tex'
    # Check if we need to (re)build
    rebuild = False
    try:
        tex_time = os.stat(os.path.join(build_dir,tex_name)).st_mtime
        # the source has changed?
        for dirpath, dirnames, filenames in os.walk(src_dir):
            for src_file in filenames:
                src_time = os.stat(os.path.join(dirpath,src_file)).st_mtime
                if src_time > tex_time:
                    rebuild = True
                    break
        # a template has changed?
        for dirpath, dirnames, filenames in os.walk(tools_dir):
            for src_file in filenames:
                src_time = os.stat(os.path.join(dirpath,src_file)).st_mtime
                if src_time > tex_time:
                    rebuild = True
                    break
    except (IOError,OSError):
        rebuild = True
    if not rebuild:
        return None
    # Build the LaTeX source
    s_files = []
    for dirpath, dirnames, filenames in os.walk(src_dir):
        s_files += [os.path.join(dirpath,fn) 
                for fn in filenames 
                if fn.endswith(('.txt','.rst'))]
    s_files.sort()
    source = ""
    for fname in s_files:
        fp = open(fname,'rt')
        try:
            source += fp.read()
        except IOError:
            pass
        finally:
            fp.close()
    if not os.path.isdir(build_dir):
        os.mkdir(build_dir)
    fp = open(os.path.join(build_dir,tex_name),'wt')
    fp.write(docutils.core.publish_string(source,
        writer_name='latex',
        settings_overrides={'language': 'it',
            'documentoptions': 'a6paper,twoside',
            'stylesheet': 'lmodern',
            'hyperlink-color': '0',
            'output_encoding': 'unicode'}))
    fp.close()

def build_pdf(guide):
    '''Builds the A6 PDF for the guide'''
    build_dir = os.path.join('build',guide)
    dist_dir = os.path.join('dist','PDF')
    tex_name = guide+'.tex'
    pdf_name = guide+'.pdf'
    # check for prerequisites
    build_latex(guide)
    # Check if we need to (re)build
    tex_time = os.stat(os.path.join(build_dir,tex_name)).st_mtime
    try:
        pdf_time = os.stat(os.path.join(dist_dir,pdf_name)).st_mtime
        if pdf_time > tex_time:
            return None
    except OSError:
        pass
    # DEBUG
    print('Building PDF...')
    if not os.path.isdir(dist_dir):
        os.mkdir(dist_dir)
    fp = open(os.path.join(dist_dir,pdf_name),'w')
    fp.close()

def build_nup_pdf(guide):
    '''Builds the nup-ed PDF for the guide'''
    dist_dir = os.path.join('dist','PDF')
    pdf_name = guide+'.pdf'
    nup_name = guide+'-A6suA4.pdf'
    # check for prerequisites
    build_pdf(guide)
    # Check if we need to (re)build
    pdf_time = os.stat(os.path.join(dist_dir,pdf_name)).st_mtime
    try:
        nup_time = os.stat(os.path.join(dist_dir,nup_name)).st_mtime
        if nup_time > pdf_time:
            return None
    except OSError:
        pass
    # DEBUG
    print('Building nup PDF...')
    if not os.path.isdir(dist_dir):
        os.mkdir(dist_dir)
    fp = open(os.path.join(dist_dir,nup_name),'w')
    fp.close()

def main():
    parser = argparse.ArgumentParser(description='Build a distribution format of a 1800 words article',
            epilog='Prerequisites of required formats are build automatically, but you may want to build the LaTeX source first, edit it by hand and then build the rest.')
    parser.add_argument('guide', nargs='+', type=basename,
            help='Source directory of the article')
    parser.add_argument('-l','--latex',action='store_true',
            help='Generate LaTeX source')
    parser.add_argument('-p','--pdf',action='store_true',
            help='Generate PDF')
    parser.add_argument('-n','--nup-pdf',action='store_true',
            help='Generate nup-ed A4 PDF')
    args = parser.parse_args()

    for guide in args.guide:
        if args.latex:
            build_latex(guide)
        if args.pdf:
            build_pdf(guide)
        if args.nup_pdf:
            build_nup_pdf(guide)


if __name__ == '__main__': main()