from io import BytesIO

from reportlab.lib import colors
from reportlab.lib.pagesizes import A4, portrait
from reportlab.lib.styles import getSampleStyleSheet
from reportlab.platypus import Paragraph, SimpleDocTemplate, Spacer, Table, TableStyle

from meal_manager.models import Event


def build_dinner_overview_pdf(event: Event) -> BytesIO:
    """Build a PDF with an overview of the event's attendance."""
    # Create an in-memory PDF
    buffer = BytesIO()
    doc = SimpleDocTemplate(
        buffer,
        pagesize=portrait(A4),
        topMargin=30,
        bottomMargin=30,
        leftMargin=40,
        rightMargin=40,
    )
    styles = getSampleStyleSheet()
    elements = []

    # Title
    title_style = styles["Title"]
    title_style.fontSize = 16
    title_style.spaceAfter = 20
    elements.append(
        Paragraph(
            f"Anwesenheitsliste – {event.title} ({event.event_time.date().strftime('%d.%m.%y')})",
            title_style,
        )
    )
    elements.append(Spacer(1, 20))

    # Team overview section
    elements.append(Paragraph("Dienste", styles["Heading2"]))
    elements.append(Spacer(1, 12))

    team_data = [["Team", "Personen"]]
    team_types = {
        "Kochen": [r for r in event.team if r.work_type == "cooking"],
        "Abwaschen": [r for r in event.team if r.work_type == "dishes"],
        "Tische decken": [r for r in event.team if r.work_type == "tables"],
    }

    for team_name, registrations in team_types.items():
        members = ", ".join(r.person_name for r in registrations)
        team_data.append([team_name, members])

    team_table = Table(team_data, repeatRows=1, colWidths=[100, "*"])
    team_table.setStyle(
        TableStyle(
            [
                ("BACKGROUND", (0, 0), (-1, 0), colors.HexColor("#E8E8E8")),
                ("GRID", (0, 0), (-1, -1), 0.5, colors.HexColor("#A0A0A0")),
                ("VALIGN", (0, 0), (-1, -1), "MIDDLE"),
                ("FONTNAME", (0, 0), (-1, 0), "Helvetica-Bold"),
                ("FONTSIZE", (0, 0), (-1, -1), 10),
                ("BOTTOMPADDING", (0, 0), (-1, -1), 8),
                ("TOPPADDING", (0, 0), (-1, -1), 8),
            ]
        )
    )

    elements.append(team_table)
    elements.append(Spacer(1, 25))

    sum_adults = 0
    sum_children = 0
    sum_small_children = 0
    for r in event.registrations:
        sum_adults += r.num_adult_meals
        sum_children += r.num_children_meals
        sum_small_children += r.num_small_children_meals

    # Attendance section
    elements.append(Paragraph("Teilnehmende", styles["Heading2"]))
    elements.append(
        Paragraph(
            f"Gesamt: {sum_adults} Erwachsene, {sum_children} Kinder, {sum_small_children} Kleinkinder"
        )
    )
    elements.append(Spacer(1, 12))

    # Table header
    data = [
        ["Haushalt", "Erwachsene", "Kinder >7", "Kinder <7", "Kommentar", "Anwesend?"]
    ]

    # Table rows
    for r in event.registrations:
        data.append(
            [
                r.household.name,
                r.num_adult_meals,
                r.num_children_meals,
                r.num_small_children_meals,
                Paragraph(r.comment or ""),
                "",
            ]
        )
    for _ in range(5):
        data.append([""] * 6)

    # Create table
    table = Table(data, repeatRows=1, colWidths=[120, 70, 60, 60, "*", 65])
    table.setStyle(
        TableStyle(
            [
                ("BACKGROUND", (0, 0), (-1, 0), colors.HexColor("#E8E8E8")),
                ("GRID", (0, 0), (-1, -1), 0.5, colors.HexColor("#A0A0A0")),
                ("ALIGN", (1, 1), (-2, -1), "CENTER"),
                ("VALIGN", (0, 0), (-1, -1), "MIDDLE"),
                ("FONTNAME", (0, 0), (-1, 0), "Helvetica-Bold"),
                ("FONTSIZE", (0, 0), (-1, -1), 10),
                ("BOTTOMPADDING", (0, 0), (-1, -1), 3),
                ("TOPPADDING", (0, 0), (-1, -1), 3),
            ]
        )
    )

    elements.append(table)
    doc.build(elements)
    buffer.seek(0)
    return buffer