import copy
import json
from collections import defaultdict
from datetime import datetime, timedelta
from io import BytesIO
from pathlib import Path
from typing import Any, Generator, List, TextIO, Tuple, Union

import pandas as pd
from flask import current_app
from reportlab.lib import colors
from reportlab.lib.enums import TA_CENTER
from reportlab.lib.styles import getSampleStyleSheet
from reportlab.lib.units import inch, mm
from reportlab.pdfbase import pdfmetrics
from reportlab.pdfbase.ttfonts import TTFont
from reportlab.platypus import PageBreak, Paragraph, SimpleDocTemplate, Table
from werkzeug.datastructures import FileStorage

from ..base.mode import ModeGroups
from ..examination_schedule.models import TermOfDefence
from ..students.models import Group, ProjectGradeSheet, Student
from .exceptions import InvalidNameOrTypeHeaderException


def check_columns(df: pd.DataFrame) -> bool:
    headers = set(df.keys().values)
    column_names = ["NAZWISKO", "IMIE", "INDEKS", "EMAIL"]
    column_types = ["object", "object", "int", "object"]
    return all((column_name in headers for column_name in column_names)) and all(
        (
            str(df.dtypes[column_name]).startswith(column_type)
            for column_name, column_type in zip(column_names, column_types)
        )
    )


def parse_csv(
    file: Union[FileStorage, TextIO], year_group_id: int
) -> Generator[Student, Any, None]:
    df = pd.read_csv(file)

    if not check_columns(df):
        raise InvalidNameOrTypeHeaderException
    students = (
        Student(
            last_name=dict(item.items())["NAZWISKO"],
            first_name=dict(item.items())["IMIE"],
            index=dict(item.items())["INDEKS"],
            email=dict(item.items())["EMAIL"],
            year_group_id=year_group_id,
        )
        for _, item in df.iterrows()
    )

    return students


def map_project_supervisors(groups: List[Group]) -> dict:
    i = 1
    mapped_project_supervisors = {}
    for group in groups:
        if group.project_supervisor_id not in mapped_project_supervisors.keys():
            mapped_project_supervisors[group.project_supervisor_id] = i
            i += 1
    return mapped_project_supervisors


def generate_csv(students_and_groups: List[Tuple[Student, Group]]) -> str:
    headers = [
        "INDEKS",
        "IMIE",
        "NAZWISKO",
        "EMAIL",
        "CDYD_KOD",
        "PRZ_KOD",
        "TZAJ_KOD",
        "GR_NR",
        "PRG_KOD",
    ]
    mapped_project_supervisors_id = map_project_supervisors(
        [group for _, group in students_and_groups]
    )
    data = [
        (
            student.index,
            student.first_name,
            student.last_name,
            student.email,
            group.cdyd_kod,
            group.prz_kod,
            group.tzaj_kod,
            mapped_project_supervisors_id[group.project_supervisor_id],
            None,
        )
        for student, group in students_and_groups
    ]
    dataframe = defaultdict(list)
    for row in data:
        for idx, item in enumerate(row):
            dataframe[headers[idx]].append(item)

    df = pd.DataFrame(dataframe)
    return df.to_csv(index=False)


def generate_range_dates(
    start_date: datetime, end_date: datetime, step_in_minutes: int
) -> Generator[Union[datetime, timedelta], Any, None]:
    current_date = copy.copy(start_date)
    while True:
        next_date = current_date + timedelta(minutes=step_in_minutes)

        if next_date > end_date:
            break
        yield current_date
        current_date = copy.copy(next_date)


def generate_examination_schedule_pdf_file(
    title: str, nested_term_of_defences: List[List[TermOfDefence]], base_dir: Path
) -> bytes:
    pagesize = (297 * mm, 210 * mm)
    headers = [
        "lp.",
        "Godzina",
        "Nazwa projektu",
        "Opiekun",
        "Zespol",
        "Komisja",
        "Uwagi",
    ]
    pdf_buffer = BytesIO()
    my_doc = SimpleDocTemplate(
        pdf_buffer,
        pagesize=pagesize,
        topMargin=1 * inch,
        leftMargin=1 * inch,
        rightMargin=1 * inch,
        bottomMargin=1 * inch,
        title=title,
    )

    pdfmetrics.registerFont(TTFont("Lato", base_dir / "fonts" / "Lato.ttf"))
    style = getSampleStyleSheet()
    bodyText = style["BodyText"]
    bodyText.fontName = "Lato"
    normal = style["Heading1"]
    normal.alignment = TA_CENTER
    flowables = []

    # print(nested_enrollments)
    for term_of_defences in nested_term_of_defences:
        if len(term_of_defences) == 0:
            continue
        date = datetime.strftime(term_of_defences[0].start_date.date(), "%d.%m.%Y")
        paragraph_1 = Paragraph(f"{title} ~ {date}", normal)
        flowables.append(paragraph_1)
        data = [headers]

        for idx, td in enumerate(term_of_defences, start=1):
            new_date = td.start_date + timedelta(hours=2)
            group_name = td.group.name if td.group is not None else ""
            if group_name != "":
                ps = td.group.project_supervisor
                project_supervisor_fullname = f"{ps.first_name[0]}. {ps.last_name}"
                students = td.group.students
                team = ", ".join([f"{s.first_name} {s.last_name}" for s in students])
            else:
                project_supervisor_fullname = ""
                team = ""

            members = td.members_of_committee

            if len(members) == 0:
                committee = ""
            else:
                members_iter = (f"{m.first_name[0]}. {m.last_name}" for m in members)
                committee = ", ".join(members_iter)

            data.append(
                [
                    str(idx),
                    new_date.strftime("%H:%M"),
                    Paragraph(group_name, bodyText),
                    Paragraph(project_supervisor_fullname, bodyText),
                    Paragraph(team, bodyText),
                    Paragraph(committee, bodyText),
                ]
            )
        # print(data)

        table = Table(
            data=data,
            style=[
                ("GRID", (0, 0), (-1, -1), 0.5, colors.black),
                ("BACKGROUND", (0, 0), (-1, 0), colors.HexColor("#A6F1A6")),
                ("BACKGROUND", (0, 0), (1, -1), colors.HexColor("#A6F1A6")),
            ],
            colWidths=[
                0.25 * inch,
                0.7 * inch,
                1.6 * inch,
                1.5 * inch,
                2.5 * inch,
                2.2 * inch,
                2 * inch,
            ],
        )
        flowables.append(table)
        flowables.append(PageBreak())

    my_doc.build(flowables)
    pdf_value = pdf_buffer.getvalue()
    pdf_buffer.close()
    return pdf_value


def get_duration_time(mode: str) -> int:
    duration_time = None
    if mode == ModeGroups.NON_STATIONARY.value:
        duration_time = 20
    elif mode in [
        ModeGroups.STATIONARY.value,
        ModeGroups.ENGLISH_SPEAKING_STATIONARY.value,
    ]:
        duration_time = 30
    return duration_time


def load_weight_for_project_grade_sheet() -> Union[dict, None]:
    base_dir = current_app.config.get("BASE_DIR")
    config_dir = base_dir / "config"

    with open(config_dir / "weights_project_grade_sheet.json") as f:
        data = json.load(f)

    return data


def get_criterion_by_weight_key(weight_key: str) -> str:
    if weight_key.startswith("presentation"):
        return "presentation"
    if weight_key.startswith("documentation"):
        return "documentation"
    if weight_key.startswith("group_work"):
        return "group_work"
    return "product_project"


def grade_in_percentage(term_key: str, term_points: dict) -> str:
    try:
        criterions = {
            "presentation": current_app.config.get(f"PRESENTATION_WEIGHT_{term_key}"),
            "group_work": current_app.config.get(f"GROUP_WORK_WEIGHT_{term_key}"),
            "documentation": current_app.config.get(f"DOCUMENTATION_WEIGHT_{term_key}"),
            "product_project": current_app.config.get(
                f"PRODUCT_PROJECT_WEIGHT_{term_key}"
            ),
        }
        result = 0
        for criterion_key, criterion_weight in criterions.items():
            result += (
                term_points[criterion_key]["gained_points"]
                / term_points[criterion_key]["all_points"]
                * criterion_weight
            )
        result /= sum(criterions.values())
    except ZeroDivisionError:
        result = 0
    return result


def calculate_points_for_both_terms(
    weights: dict, project_grade_sheets: List[ProjectGradeSheet]
) -> list:
    terms = []
    for pgs in project_grade_sheets:
        if pgs is None:
            terms.append((0, 0))
            continue
        first_term_points = {
            "presentation": {"gained_points": 0, "all_points": 0},
            "documentation": {"gained_points": 0, "all_points": 0},
            "group_work": {"gained_points": 0, "all_points": 0},
            "product_project": {"gained_points": 0, "all_points": 0},
        }

        second_term_points = copy.deepcopy(first_term_points)

        for weight_key, weight_value in weights.items():
            points = (
                first_term_points if weight_key.endswith("1") else second_term_points
            )
            criterion = get_criterion_by_weight_key(weight_key)
            try:
                attribute_value = getattr(pgs, weight_key)
            except AttributeError:
                attribute_value = 0
            points[criterion]["gained_points"] += attribute_value / 4 * weight_value
            points[criterion]["all_points"] += weight_value

        points_1 = round(grade_in_percentage("FIRST_TERM", first_term_points) * 100, 1)
        points_2 = round(
            grade_in_percentage("SECOND_TERM", second_term_points) * 100, 1
        )
        terms.append((points_1, points_2))
    return terms


def attach_points_for_first_and_second_term_to_group_models(items: List[Group]) -> None:
    weights = load_weight_for_project_grade_sheet()
    pgs = []
    for g in items:
        if len(g.project_grade_sheet) == 0:
            pgs.append(None)
        else:
            pgs.append(g.project_grade_sheet[0])
    calculated_points = calculate_points_for_both_terms(weights, pgs)

    for group, points in zip(items, calculated_points):
        group.points_for_first_term = points[0]
        group.points_for_second_term = points[1]