import json
import pandas as pd
import os
from pypdf import PdfReader
import re
from tqdm import tqdm


def extract_invoice_tables(invoices_path: str) -> list[str]:
    invoices_paths = [os.path.join(invoices_path, invoice) for invoice in os.listdir(invoices_path) if
                      invoice.endswith(".pdf")]
    invoices_tables = []
    for invoice_path in tqdm(invoices_paths):
        reader = PdfReader(invoice_path)
        page = reader.pages[0]
        text = page.extract_text()

        table_text = re.search(r"Beschädigtes Teil.*?Gesamtsumme:.*?EUR", text, re.DOTALL).group()

        lines = table_text.splitlines()
        header = lines[0]
        other_text = "\n".join(lines[1:])
        cleaned_text = re.sub(r"(?<!\d)\n", " ", other_text)

        table = header + "\n" + cleaned_text

        inv = table.split("\n")
        reformatted_inv = "Beschädigtes Teil | Teilkosten (EUR) | Arbeitsstunden | Arbeitskosten (EUR/Stunde) | Gesamtkosten (EUR)\n" + "\n".join(
            " ".join(inv[i].split(" ")[:-4]) + " | " + ' | '.join(inv[i].split(" ")[-4:]) for i in
            range(1, len(inv) - 1)) + "\n" + inv[-1]

        invoices_tables.append(reformatted_inv)

    return invoices_tables


def get_car_parts(invoices: list[str]) -> list[tuple[str, str, str]]:
    car_parts = []
    for invoice in invoices:
        car_parts += [
            (
                line.split(" | ")[0].replace("(rechts)", "").replace("(links)", "").strip(),
                line.split(" | ")[1],
                line.split(" | ")[2]
            )
            for line in invoice.split("\n")[1:-1]
        ]
    return car_parts


def estimate_costs(invoices_folder_path: str, path_to_save_json: str) -> pd.DataFrame:
    invoices = extract_invoice_tables(invoices_folder_path)
    car_parts = get_car_parts(invoices)

    car_parts_df = pd.DataFrame(car_parts, columns=["car_part", "cost", "hours"])
    car_parts_df["cost"] = car_parts_df["cost"].astype(float)
    car_parts_df["hours"] = car_parts_df["hours"].astype(float)
    car_parts_df = car_parts_df.groupby("car_part").agg(
        {"cost": ["mean", "min", "max", "count"], "hours": ["mean", "min", "max"]}
    )
    car_parts_df.columns = [
        "average_cost", "cost_min", "cost_max", "count", "average_hours", "hours_min", "hours_max"
    ]

    car_parts_dict = car_parts_df.to_dict(
        orient="index"
    )

    with open(path_to_save_json, "w", encoding="utf-8") as f:
        json.dump(car_parts_dict, f, ensure_ascii=False, indent=4)

    return car_parts_df