# The Mia! Accounting Project.
# Author: imacat@mail.imacat.idv.tw (imacat), 2023/1/27

#  Copyright (c) 2023 imacat.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.
"""The common test libraries.

"""
from __future__ import annotations

import re
import typing as t
from abc import ABC, abstractmethod
from datetime import date, timedelta
from decimal import Decimal
from secrets import randbelow

import httpx
import sqlalchemy as sa
from flask import Flask, render_template_string

from test_site import create_app, db
from test_site.auth import User

TEST_SERVER: str = "https://testserver"
"""The test server URI."""
NEXT_URI: str = "/_next"
"""The next URI."""


class Accounts:
    """The shortcuts to the common accounts."""
    CASH: str = "1111-001"
    PETTY_CASH: str = "1112-001"
    BANK: str = "1113-001"
    NOTES_RECEIVABLE: str = "1131-001"
    RECEIVABLE: str = "1141-001"
    MACHINERY: str = "1441-001"
    PREPAID: str = "1258-001"
    NOTES_PAYABLE: str = "2131-001"
    PAYABLE: str = "2141-001"
    SALES: str = "4111-001"
    SERVICE: str = "4611-001"
    AGENCY: str = "4711-001"
    RENT_EXPENSE: str = "6252-001"
    OFFICE: str = "6253-001"
    TRAVEL: str = "6254-001"
    POSTAGE: str = "6256-001"
    UTILITIES: str = "6261-001"
    INSURANCE: str = "6262-001"
    MEAL: str = "6272-001"
    INTEREST: str = "7111-001"
    DONATION: str = "7481-001"
    RENT_INCOME: str = "7482-001"


def create_test_app() -> Flask:
    """Creates and returns the testing Flask application.

    :return: The testing Flask application.
    """
    app: Flask = create_app(is_testing=True)

    @app.get("/.csrf-token")
    def get_csrf_token_view() -> str:
        """The test view to return the CSRF token."""
        return render_template_string("{{csrf_token()}}")

    @app.get("/.errors")
    def get_errors_view() -> str:
        """The test view to return the CSRF token."""
        return render_template_string("{{get_flashed_messages()|tojson}}")

    return app


def get_csrf_token(client: httpx.Client) -> str:
    """Returns the CSRF token.

    :param client: The httpx client.
    :return: The CSRF token.
    """
    return client.get("/.csrf-token").text


def get_client(app: Flask, username: str) -> tuple[httpx.Client, str]:
    """Returns a user client.

    :param app: The Flask application.
    :param username: The username.
    :return: A tuple of the client and the CSRF token.
    """
    client: httpx.Client = httpx.Client(app=app, base_url=TEST_SERVER)
    client.headers["Referer"] = TEST_SERVER
    csrf_token: str = get_csrf_token(client)
    response: httpx.Response = client.post("/login",
                                           data={"csrf_token": csrf_token,
                                                 "next": "/",
                                                 "username": username})
    assert response.status_code == 302
    assert response.headers["Location"] == "/"
    return client, csrf_token


def set_locale(client: httpx.Client, csrf_token: str,
               locale: t.Literal["en", "zh_Hant", "zh_Hans"]) -> None:
    """Sets the current locale.

    :param client: The test client.
    :param csrf_token: The CSRF token.
    :param locale: The locale.
    :return: None.
    """
    response: httpx.Response = client.post("/locale",
                                           data={"csrf_token": csrf_token,
                                                 "locale": locale,
                                                 "next": "/next"})
    assert response.status_code == 302
    assert response.headers["Location"] == "/next"


def add_journal_entry(client: httpx.Client, form: dict[str, str]) -> int:
    """Adds a transfer journal entry.

    :param client: The client.
    :param form: The form data.
    :return: The newly-added journal entry ID.
    """
    prefix: str = "/accounting/journal-entries"
    journal_entry_type: str = "transfer"
    if len({x for x in form if "-debit-" in x}) == 0:
        journal_entry_type = "receipt"
    elif len({x for x in form if "-credit-" in x}) == 0:
        journal_entry_type = "disbursement"
    store_uri = f"{prefix}/store/{journal_entry_type}"
    response: httpx.Response = client.post(store_uri, data=form)
    assert response.status_code == 302
    return match_journal_entry_detail(response.headers["Location"])


def match_journal_entry_detail(location: str) -> int:
    """Validates if the redirect location is the journal entry detail, and
    returns the journal entry ID on success.

    :param location: The redirect location.
    :return: The journal entry ID.
    :raise AssertionError: When the location is not the journal entry detail.
    """
    m: re.Match = re.match(
        r"^/accounting/journal-entries/(\d+)\?next=%2F_next", location)
    assert m is not None
    return int(m.group(1))


class JournalEntryLineItemData:
    """The journal entry line item data."""

    def __init__(self, account: str, description: str | None, amount: str,
                 original_line_item: JournalEntryLineItemData | None = None):
        """Constructs the journal entry line item data.

        :param account: The account code.
        :param description: The description.
        :param amount: The amount.
        :param original_line_item: The original journal entry line item.
        """
        self.journal_entry: JournalEntryData | None = None
        self.id: int = -1
        self.no: int = -1
        self.original_line_item: JournalEntryLineItemData | None \
            = original_line_item
        self.account: str = account
        self.description: str | None = description
        self.amount: Decimal = Decimal(amount)

    def form(self, prefix: str, debit_credit: str, index: int,
             is_update: bool) -> dict[str, str]:
        """Returns the line item as form data.

        :param prefix: The prefix of the form fields.
        :param debit_credit: Either "debit" or "credit".
        :param index: The line item index.
        :param is_update: True for an update operation, or False otherwise
        :return: The form data.
        """
        prefix = f"{prefix}-{debit_credit}-{index}"
        form: dict[str, str] = {f"{prefix}-account_code": self.account,
                                f"{prefix}-description": self.description,
                                f"{prefix}-amount": str(self.amount)}
        if is_update and self.id != -1:
            form[f"{prefix}-id"] = str(self.id)
        form[f"{prefix}-no"] = str(index) if self.no == -1 else str(self.no)
        if self.original_line_item is not None:
            assert self.original_line_item.id != -1
            form[f"{prefix}-original_line_item_id"] \
                = str(self.original_line_item.id)
        return form


class JournalEntryCurrencyData:
    """The journal entry currency data."""

    def __init__(self, currency: str, debit: list[JournalEntryLineItemData],
                 credit: list[JournalEntryLineItemData]):
        """Constructs the journal entry currency data.

        :param currency: The currency code.
        :param debit: The debit line items.
        :param credit: The credit line items.
        """
        self.code: str = currency
        self.debit: list[JournalEntryLineItemData] = debit
        self.credit: list[JournalEntryLineItemData] = credit

    def form(self, index: int, is_update: bool) -> dict[str, str]:
        """Returns the currency as form data.

        :param index: The currency index.
        :param is_update: True for an update operation, or False otherwise
        :return: The form data.
        """
        prefix: str = f"currency-{index}"
        form: dict[str, str] = {f"{prefix}-code": self.code}
        for i in range(len(self.debit)):
            form.update(self.debit[i].form(prefix, "debit", i + 1, is_update))
        for i in range(len(self.credit)):
            form.update(self.credit[i].form(prefix, "credit", i + 1,
                                            is_update))
        return form


class JournalEntryData:
    """The journal entry data."""

    def __init__(self, days: int, currencies: list[JournalEntryCurrencyData]):
        """Constructs a journal entry.

        :param days: The number of days before today.
        :param currencies: The journal entry currency data.
        """
        self.id: int = -1
        self.days: int = days
        self.currencies: list[JournalEntryCurrencyData] = currencies
        self.note: str | None = None
        for currency in self.currencies:
            for line_item in currency.debit:
                line_item.journal_entry = self
            for line_item in currency.credit:
                line_item.journal_entry = self

    def new_form(self, csrf_token: str, next_uri: str) -> dict[str, str]:
        """Returns the journal entry as a creation form.

        :param csrf_token: The CSRF token.
        :param next_uri: The next URI.
        :return: The journal entry as a creation form.
        """
        return self.__form(csrf_token, next_uri, is_update=False)

    def update_form(self, csrf_token: str, next_uri: str) -> dict[str, str]:
        """Returns the journal entry as an update form.

        :param csrf_token: The CSRF token.
        :param next_uri: The next URI.
        :return: The journal entry as an update form.
        """
        return self.__form(csrf_token, next_uri, is_update=True)

    def __form(self, csrf_token: str, next_uri: str, is_update: bool = False) \
            -> dict[str, str]:
        """Returns the journal entry as a form.

        :param csrf_token: The CSRF token.
        :param next_uri: The next URI.
        :param is_update: True for an update operation, or False otherwise
        :return: The journal entry as a form.
        """
        journal_entry_date: date = date.today() - timedelta(days=self.days)
        form: dict[str, str] = {"csrf_token": csrf_token,
                                "next": next_uri,
                                "date": journal_entry_date.isoformat()}
        for i in range(len(self.currencies)):
            form.update(self.currencies[i].form(i + 1, is_update))
        if self.note is not None:
            form["note"] = self.note
        return form


class BaseTestData(ABC):
    """The base test data."""

    def __init__(self, app: Flask, username: str):
        """Constructs the test data.

        :param app: The Flask application.
        :param username: The username.
        """
        self._app: Flask = app
        with self._app.app_context():
            current_user: User | None = User.query\
                .filter(User.username == username).first()
            assert current_user is not None
            self.__current_user_id: int = current_user.id
            self._journal_entries: list[dict[str, t.Any]] = []
            self._line_items: list[dict[str, t.Any]] = []
            self._init_data()

    @abstractmethod
    def _init_data(self) -> None:
        """Initializes the test data.

        :return: None
        """

    def populate(self) -> None:
        """Populates the data into the database.

        :return: None
        """
        from accounting.models import JournalEntry, JournalEntryLineItem
        with self._app.app_context():
            db.session.execute(sa.insert(JournalEntry), self._journal_entries)
            db.session.execute(sa.insert(JournalEntryLineItem),
                               self._line_items)
            db.session.commit()

    @property
    def csv_data(self) -> tuple[list[dict[str, t.Any]],
                                list[dict[str, t.Any]]]:
        """Returns the data for CSV.

        :return: The data for CSV.
        """
        from accounting.models import Account
        today: date = date.today()

        def filter_journal_entry(data: dict[str, t.Any]) -> dict[str, t.Any]:
            """Filters the journal entry data for JSON encoding.

            :param data: The journal entry data.
            :return: The journal entry data for JSON encoding.
            """
            data = data.copy()
            data["date"] = (today - data["date"]).days
            del data["created_by_id"]
            del data["updated_by_id"]
            return data

        def filter_line_item(data: dict[str, t.Any]) -> dict[str, t.Any]:
            """Filters the journal entry line item data for JSON encoding.

            :param data: The journal entry line item data.
            :return: The journal entry line item data for JSON encoding.
            """
            data = data.copy()
            with self._app.app_context():
                data["account_id"] \
                    = db.session.get(Account, data["account_id"]).code
            if "original_line_item_id" not in data:
                data["original_line_item_id"] = None
            return data

        return [filter_journal_entry(x) for x in self._journal_entries], \
            [filter_line_item(x) for x in self._line_items]

    @staticmethod
    def _couple(description: str, amount: str, debit: str, credit: str) \
            -> tuple[JournalEntryLineItemData, JournalEntryLineItemData]:
        """Returns a couple of debit-credit line items.

        :param description: The description.
        :param amount: The amount.
        :param debit: The debit account code.
        :param credit: The credit account code.
        :return: The debit line item and credit line item.
        """
        return JournalEntryLineItemData(debit, description, amount),\
            JournalEntryLineItemData(credit, description, amount)

    def _add_journal_entry(self, journal_entry_data: JournalEntryData) -> None:
        """Adds a journal entry.

        :param journal_entry_data: The journal entry data.
        :return: None.
        """
        from accounting.models import Account
        existing_j_id: set[int] = {x["id"] for x in self._journal_entries}
        existing_l_id: set[int] = {x["id"] for x in self._line_items}
        journal_entry_data.id = self.__new_id(existing_j_id)
        j_date: date = date.today() - timedelta(days=journal_entry_data.days)
        self._journal_entries.append(
            {"id": journal_entry_data.id,
             "date": j_date,
             "no": self.__next_j_no(j_date),
             "note": journal_entry_data.note,
             "created_by_id": self.__current_user_id,
             "updated_by_id": self.__current_user_id})
        debit_no: int = 0
        credit_no: int = 0
        for currency in journal_entry_data.currencies:
            for line_item in currency.debit:
                account: Account | None \
                    = Account.find_by_code(line_item.account)
                assert account is not None
                debit_no = debit_no + 1
                line_item.id = self.__new_id(existing_l_id)
                data: dict[str, t.Any] \
                    = {"id": line_item.id,
                       "journal_entry_id": journal_entry_data.id,
                       "is_debit": True,
                       "no": debit_no,
                       "account_id": account.id,
                       "currency_code": currency.code,
                       "description": line_item.description,
                       "amount": line_item.amount}
                if line_item.original_line_item is not None:
                    data["original_line_item_id"] \
                        = line_item.original_line_item.id
                self._line_items.append(data)
            for line_item in currency.credit:
                account: Account | None \
                    = Account.find_by_code(line_item.account)
                assert account is not None
                credit_no = credit_no + 1
                line_item.id = self.__new_id(existing_l_id)
                data: dict[str, t.Any] \
                    = {"id": line_item.id,
                       "journal_entry_id": journal_entry_data.id,
                       "is_debit": False,
                       "no": credit_no,
                       "account_id": account.id,
                       "currency_code": currency.code,
                       "description": line_item.description,
                       "amount": line_item.amount}
                if line_item.original_line_item is not None:
                    data["original_line_item_id"] \
                        = line_item.original_line_item.id
                self._line_items.append(data)

    @staticmethod
    def __new_id(existing_id: set[int]) -> int:
        """Generates and returns a new random unique ID.

        :param existing_id: The existing ID.
        :return: The newly-generated random unique ID.
        """
        while True:
            obj_id: int = 100000000 + randbelow(900000000)
            if obj_id not in existing_id:
                existing_id.add(obj_id)
                return obj_id

    def __next_j_no(self, j_date: date) -> int:
        """Returns the next journal entry number in a day.

        :param j_date: The journal entry date.
        :return: The next journal entry number.
        """
        existing: set[int] = {x["no"] for x in self._journal_entries
                              if x["date"] == j_date}
        return 1 if len(existing) == 0 else max(existing) + 1

    def _add_simple_journal_entry(
            self, days: int, currency: str, description: str, amount: str,
            debit: str, credit: str) \
            -> tuple[JournalEntryLineItemData, JournalEntryLineItemData]:
        """Adds a simple journal entry.

        :param days: The number of days before today.
        :param currency: The currency code.
        :param description: The description.
        :param amount: The amount.
        :param debit: The debit account code.
        :param credit: The credit account code.
        :return: The debit line item and credit line item.
        """
        debit_item, credit_item = self._couple(
            description, amount, debit, credit)
        self._add_journal_entry(JournalEntryData(
            days, [JournalEntryCurrencyData(
                currency, [debit_item], [credit_item])]))
        return debit_item, credit_item