from datetime import datetime
from pathlib import Path
from types import SimpleNamespace

from jinja2 import Environment, FileSystemLoader, select_autoescape

from ..summary import YearView
from .charts import change_bars, grouped_bars
from .i18n import T

TEMPLATES = Path(__file__).parent / "templates"
env = Environment(loader=FileSystemLoader(TEMPLATES), autoescape=select_autoescape(["html"]))
CSS = (TEMPLATES / "report.css").read_text()


def _exported() -> str:
    return datetime.now().strftime("%Y-%m-%d %H:%M")


def cost_report_html(view: YearView, lang: str, site: str | None = None, screen: bool = True) -> str:
    t = T(lang, view.year.year, view.year.department.name)
    cost_cats = view.with_lines("cost")
    cats = []
    for cv in cost_cats:
        rows = [(lv.line.name, float(lv.figures.prior), float(lv.figures.adjusted)) for lv in cv.lines]
        cats.append(SimpleNamespace(
            name=cv.name(lang), count=len(cv.lines), totals=cv.totals,
            chart=grouped_bars(rows, t.short_eur, lambda v: t.eur(v, 0))))
    overview = grouped_bars([(c.name, float(c.totals.prior), float(c.totals.adjusted)) for c in cats], t.short_eur)
    ranked = sorted([c for c in cats if c.totals.change_pct is not None],
                    key=lambda c: c.totals.change_pct, reverse=True)
    change = change_bars([(c.name, float(c.totals.change_pct)) for c in ranked], lambda v: t.pct(v))
    return env.get_template("cost_report.html").render(
        t=t, title=t("cost_report_title"), year=view.year, site=site, cats=cats, costs=view.costs,
        overview_chart=overview, change_chart=change, exported=_exported(), css=CSS, screen=screen)


def budget_html(view: YearView, lang: str, site: str | None = None, include_empty: bool = False) -> str:
    t = T(lang, view.year.year, view.year.department.name)
    cats = [SimpleNamespace(name=cv.name(lang), category=cv.category, lines=cv.lines, totals=cv.totals)
            for cv in view.categories if cv.lines or include_empty]
    # revenue first, as in the Budget IT sheet
    cats.sort(key=lambda c: 0 if c.category.section == "revenue" else 1)
    return env.get_template("budget.html").render(
        t=t, title=t("budget_title"), year=view.year, site=site, cats=cats, costs=view.costs,
        exported=_exported(), css=CSS)


def to_pdf(html: str) -> bytes:
    from weasyprint import HTML  # imported lazily: it loads system libraries

    return HTML(string=html).write_pdf()