# -*- coding: utf-8 -*-
#
# (c) 2014 by Björn Ricks <bjoern.ricks@intevation.de>
#
# This is Free Software licensed under the terms of GPLv3 or later.
# For details see LICENSE coming with the source of 'getan'.

import os.path
import sys

from datetime import date, datetime, timedelta

from jinja2 import Environment, ChoiceLoader, FileSystemLoader, PackageLoader

from getan.backend import Backend, DEFAULT_DATABASE


def human_time(delta):
    days = delta.days
    seconds = days * 3600 * 24
    s = seconds + delta.seconds
    h = s / 3600
    m = (s % 3600) / 60
    if (s % 60) >= 30:
        m += 1
        if m == 60:
            m = 0
            h += 1
    return "%d:%02d" % (h, m)


def date_format(d):
    return d.strftime("%d.%m.%Y")


def duration(entries):
    total = timedelta(0)
    for entry in entries:
        total += entry.get_duration()
    return total


def unix_week(week, year=None):
    """Convert iso week to unix week

    For unix week see man date "%W"
    Args:
        week: Week number as int to convert
        year: Year as int. If year is none the current year is used.
    """
    if not year:
        year = datetime.now().year
    firstday = date(year, 1, 4)
    isoweek = firstday.isocalendar()[1]
    unixweek = int(firstday.strftime("%W"))
    diff = isoweek - unixweek
    return week - diff


def render(template, database=None, year=None, week=None, project=None,
           user=None, empty_projects=True):
    if not user:
        user = os.getenv("USER")

    if not database:
        if os.path.isfile(DEFAULT_DATABASE):
            database = os.path.abspath(DEFAULT_DATABASE)
        else:
            database = os.path.expanduser(os.path.join("~", ".getan",
                                                       DEFAULT_DATABASE))
    if not os.path.isfile(database):
        print >> sys.stderr, "'%s' does not exist or is not a file." % database
        sys.exit(1)

    u_week = None

    c_year = int(date.today().strftime("%Y"))
    c_week = datetime.now().isocalendar()[1]

    if week is not None and year is None:
        year = c_year

    if not os.path.isfile(database):
        print >> sys.stderr, "'%s' does not exist or is not a file." % database
        sys.exit(1)

    loader = ChoiceLoader([FileSystemLoader(os.path.expanduser(os.path.join(
        "~", ".getan", "templates"))),
        PackageLoader("getan")])

    env = Environment(loader=loader)
    env.filters["human_time"] = human_time
    env.filters["date_format"] = date_format
    env.filters["duration"] = duration

    template_name = template or "wochenbericht"
    template = env.get_template(template_name)

    backend = Backend(database)

    if not project:
        projects = backend.load_projects()
    else:
        project = backend.load_project(project)
        projects = [project]

    if year is not None or week is not None:
        u_week = "%02d" % unix_week(week, year)
        for project in projects:
            project.load_entries(year, u_week)

    if not empty_projects:
        projects = [project for project in projects if project.entries]

    entries = []
    for project in projects:
        entries.extend(project.entries)

    context = dict()
    context["entries"] = entries
    context["project"] = project
    context["projects"] = projects
    context["user"] = user
    context["database"] = database
    context["year"] = year
    context["week"] = week
    context["current_week"] = c_week
    context["current_year"] = c_year
    context["unix_week"] = u_week
    context["total_time"] = duration(entries)
    context["today"] = date.today()
    return template.render(context)