#!/usr/bin/env python3

import argparse
import calendar
import datetime
import locale
import logging
import os
import shutil
import subprocess
import sys

from typing import Optional

try:
    from lesana.command import _get_first_docstring_line  # type: ignore
except ImportError:
    def _get_first_docstring_line(obj):
        return ""

try:
    import argcomplete  # type: ignore
except ImportError:
    argcomplete = False

import jinja2


locale.setlocale(locale.LC_ALL, '')


class Generator:
    """
    """
    default_template = "planner-A6"

    def __init__(
            self,
            year: Optional[int] = None,
            template: Optional[str] = None,
            out_file: Optional[str] = None,
            build_dir: Optional[str] = "build",
    ):
        self.year = year or (
            datetime.date.today() + datetime.timedelta(days=334)
        ).year

        self.out_file = out_file or self.default_template + ".pdf"

        env = jinja2.Environment()
        self.templates_dir = "templates"
        loader = jinja2.FileSystemLoader(self.templates_dir)
        if not template:
            template = self.default_template
        self.template_recto = loader.load(env, template + "-r.svg")
        self.template_verso = loader.load(env, template + "-v.svg")
        self.template_cover = loader.load(env, "cover-A6-r.svg")
        self.build_dir = build_dir
        self.page_fname = os.path.join(
            self.build_dir,
            template + "-{year}-{page:03}.svg"
        )

    def render_page(self, page: int, **kw):
        # page counts starts with 0
        if page == 0:
            template = self.template_cover
        elif page % 2 == 0:
            template = self.template_recto
        else:
            template = self.template_verso
        with open(self.page_fname.format(
                year=self.year, page=page
        ), "w") as fp:
            fp.write(template.render(**kw))

    def run(self):
        self.clean_build_dir()
        self.generate_cover_page()
        self.generate_pages()
        self.convert_pages_to_svg()
        self.join_pages()

    def clean_build_dir(self):
        try:
            shutil.rmtree(self.build_dir)
        except FileNotFoundError:
            pass
        os.makedirs(self.build_dir)

    def generate_cover_page(self):
        self.render_page(page=0, year=self.year)

    def generate_pages(self):
        pass

    def convert_pages_to_svg(self):
        inkscape_commands = ";\n".join([
            (
                "file-open:{build_dir}/{svg};"
                + " export-type: pdf;"
                + " export-filename:build/{pdf};"
                + " export-text-to-path;"
                + " export-do"
            ).format(
                build_dir=self.build_dir,
                svg=s,
                pdf=os.path.splitext(s)[0] + ".pdf",
            )
            for s in os.listdir(self.build_dir)
        ])
        try:
            subprocess.run(
                ["inkscape", "--shell"],
                input=inkscape_commands,
                text=True,
            )
        except FileNotFoundError:
            logging.warning("Inkscape is not installed, can't convert to pdf")
            logging.warning("Stopping here, you can use the svgs as you like")
            sys.exit(1)

    def get_pdf_pages(self):
        pdf_pages = sorted([
            os.path.join(self.build_dir, p)
            for p in os.listdir(self.build_dir)
            if p.endswith(".pdf")
        ])
        return pdf_pages

    def join_pages(self):
        pdf_pages = self.get_pdf_pages()
        try:
            subprocess.run([
                "pdfjam",
                "--outfile", self.out_file,
                *pdf_pages
            ])
        except FileNotFoundError:
            logging.warning("pdfjam is not installed")
            logging.warning("you will have to join the pdf pages yourself")
            sys.exit(1)


class WeeklyGenerator(Generator):
    default_template = "week_on_two_pages-A6"

    def generate_pages(self):
        cal = calendar.Calendar()
        weeks = sum(
            [r[0] for r in cal.yeardatescalendar(self.year, width=1)],
            []
        )

        last_monday = None
        page = 1
        for week in weeks:
            # yeardatescalendar will have the same week twice at the
            # margin of a month, but we want to skip one of those
            if week[0] == last_monday:
                continue
            last_monday = week[0]

            self.render_page(page=page, week=week)
            page += 1

            self.render_page(page=page, week=week)
            page += 1


class DailyGenerator(Generator):
    default_template = "daily-A6"

    def generate_pages(self):
        day = datetime.date(self.year, 1, 1)

        # we want to start with a left side page (starting from 0)
        page = 2
        while day.year == self.year:
            self.render_page(page=page, day=day)
            page += 1
            day += datetime.timedelta(days=1)

            if day.year > self.year:
                break

            self.render_page(page=page, day=day)
            page += 1
            day += datetime.timedelta(days=1)

    def get_pdf_pages(self):
        pdf_pages = super().get_pdf_pages()
        # insert an empty page on the second page, to start the year on
        # a left page
        pdf_pages.insert(1, "1, {}")

        return pdf_pages


class MonthGenerator(Generator):
    """
    """
    default_template = "month-A6"

    def generate_pages(self):
        cal = calendar.Calendar()
        full_year = cal.yeardatescalendar(self.year, width=1)
        months = []

        for i in range(12):
            months.append([
                day for week in full_year[i][0] for day in week
                if day.month == i + 1
            ])

        page = 1
        for month in months:
            self.render_page(page=page, month=month, text=[])
            page += 1


class Command:
    """
    Generate a planner
    """
    def get_parser(self):
        desc = _get_first_docstring_line(self)
        parser = argparse.ArgumentParser(description=desc)
        parser.add_argument(
            "--year", '-y',
            default=None,
            help="Default is next year, or this year in January."
        )
        parser.add_argument(
            "--template", '-t',
            default=None,
            help="Base name of the template (without -[rv].svg)",
        )
        parser.add_argument(
            "command",
        )
        return parser

    def main(self):
        self.parser = self.get_parser()
        if argcomplete:
            argcomplete.autocomplete(self.parser)
        self.args = self.parser.parse_args()

        generator = getattr(
            sys.modules[__name__],
            self.args.command.capitalize() + "Generator",
            None
        )
        if generator:
            generator(
                year=self.args.year,
                template=self.args.template,
            ).run()
        else:
            print("command not supported: {}".format(self.args.command))


if __name__ == "__main__":
    Command().main()