from __future__ import annotations

from flask import Blueprint, flash, redirect, render_template, request, url_for
from flask_login import login_required
from sqlalchemy import select

from app.extensions import db
from app.models import (
    Account,
    Category,
    CostParticipant,
    Entry,
    EntryShareRule,
    MonthlyEntryValue,
    Month,
    NotificationPreference,
    User,
)
from app.seed import slugify
from app.utils.uploads import save_avatar_upload
from app.utils.decorators import admin_required

admin_bp = Blueprint("admin", __name__, url_prefix="/admin")


def _resolve_avatar_url(existing: str | None = None) -> str | None:
    upload = request.files.get("avatar_file")
    if upload and upload.filename:
        try:
            return save_avatar_upload(upload)
        except ValueError as exc:
            flash(str(exc), "danger")
            return existing
    avatar_url = request.form.get("avatar_url")
    if avatar_url is not None:
        avatar_url = avatar_url.strip()
        return avatar_url or existing
    return existing


@admin_bp.route("/")
@login_required
@admin_required
def index():
    users = User.query.order_by(User.display_name.asc(), User.username.asc()).all()
    participants = CostParticipant.query.order_by(CostParticipant.name.asc()).all()
    accounts = db.session.scalars(select(Account).order_by(Account.sort_order.asc(), Account.name.asc())).all()
    categories = db.session.scalars(
        select(Category).order_by(Category.account_id.asc(), Category.sort_order.asc(), Category.name.asc())
    ).all()
    entries = db.session.scalars(
        select(Entry).order_by(Entry.category_id.asc(), Entry.sort_order.asc(), Entry.name.asc())
    ).all()
    return render_template(
        "admin/index.html",
        users=users,
        participants=participants,
        accounts=accounts,
        categories=categories,
        entries=entries,
    )


@admin_bp.route("/users", methods=["POST"])
@login_required
@admin_required
def create_user():
    user = User(
        username=request.form["username"].strip(),
        display_name=request.form["display_name"].strip(),
        email=request.form["email"].strip(),
        avatar_url=_resolve_avatar_url(),
        role=request.form.get("role", "editor"),
        is_active=True,
    )
    user.set_password(request.form["password"])
    db.session.add(user)
    db.session.flush()
    db.session.add(NotificationPreference(user_id=user.id))
    db.session.commit()
    flash("Benutzer angelegt.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/users/<int:user_id>", methods=["POST"])
@login_required
@admin_required
def update_user(user_id: int):
    user = User.query.get_or_404(user_id)
    user.display_name = request.form["display_name"].strip()
    user.email = request.form["email"].strip()
    user.avatar_url = _resolve_avatar_url(user.avatar_url)
    user.role = request.form.get("role", user.role)
    user.is_active = request.form.get("is_active") == "on"
    db.session.commit()
    flash("Benutzer aktualisiert.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/users/<int:user_id>/toggle", methods=["POST"])
@login_required
@admin_required
def toggle_user(user_id: int):
    user = User.query.get_or_404(user_id)
    user.is_active = not user.is_active
    db.session.commit()
    flash("Benutzerstatus aktualisiert.", "info")
    return redirect(url_for("admin.index"))


@admin_bp.route("/participants", methods=["POST"])
@login_required
@admin_required
def create_participant():
    participant = CostParticipant(
        name=request.form["name"].strip(),
        avatar_url=_resolve_avatar_url(),
        is_external=request.form.get("is_external") == "on",
        is_app_user=bool(request.form.get("linked_user_id")),
        linked_user_id=int(request.form["linked_user_id"]) if request.form.get("linked_user_id") else None,
        is_active=True,
    )
    db.session.add(participant)
    db.session.commit()
    flash("Beteiligte Person angelegt.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/participants/<int:participant_id>", methods=["POST"])
@login_required
@admin_required
def update_participant(participant_id: int):
    participant = CostParticipant.query.get_or_404(participant_id)
    participant.name = request.form["name"].strip()
    participant.avatar_url = _resolve_avatar_url(participant.avatar_url)
    participant.is_external = request.form.get("is_external") == "on"
    participant.linked_user_id = (
        int(request.form["linked_user_id"]) if request.form.get("linked_user_id") else None
    )
    participant.is_app_user = participant.linked_user_id is not None
    participant.is_active = request.form.get("is_active") == "on"
    db.session.commit()
    flash("Beteiligte Person aktualisiert.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/accounts", methods=["POST"])
@login_required
@admin_required
def create_account():
    name = request.form["name"].strip()
    account = Account(
        name=name,
        slug=slugify(request.form.get("slug", "") or name),
        description=request.form.get("description", "").strip() or None,
        sort_order=int(request.form.get("sort_order") or 0),
        is_active=request.form.get("is_active") == "on",
    )
    db.session.add(account)
    db.session.commit()
    flash("Konto angelegt.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/accounts/<int:account_id>", methods=["POST"])
@login_required
@admin_required
def update_account(account_id: int):
    account = Account.query.get_or_404(account_id)
    name = request.form["name"].strip()
    account.name = name
    account.slug = slugify(request.form.get("slug", "") or name)
    account.description = request.form.get("description", "").strip() or None
    account.sort_order = int(request.form.get("sort_order") or 0)
    account.is_active = request.form.get("is_active") == "on"
    db.session.commit()
    flash("Konto aktualisiert.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/categories", methods=["POST"])
@login_required
@admin_required
def create_category():
    name = request.form["name"].strip()
    category = Category(
        account_id=int(request.form["account_id"]),
        name=name,
        slug=slugify(request.form.get("slug", "") or name),
        description=request.form.get("description", "").strip() or None,
        sort_order=int(request.form.get("sort_order") or 0),
        is_active=request.form.get("is_active") == "on",
    )
    db.session.add(category)
    db.session.commit()
    flash("Kategorie angelegt.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/categories/<int:category_id>", methods=["POST"])
@login_required
@admin_required
def update_category(category_id: int):
    category = Category.query.get_or_404(category_id)
    name = request.form["name"].strip()
    category.account_id = int(request.form["account_id"])
    category.name = name
    category.slug = slugify(request.form.get("slug", "") or name)
    category.description = request.form.get("description", "").strip() or None
    category.sort_order = int(request.form.get("sort_order") or 0)
    category.is_active = request.form.get("is_active") == "on"
    db.session.commit()
    flash("Kategorie aktualisiert.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/entries", methods=["POST"])
@login_required
@admin_required
def create_entry():
    name = request.form["name"].strip()
    entry = Entry(
        category_id=int(request.form["category_id"]),
        name=name,
        slug=slugify(request.form.get("slug", "") or name),
        description=request.form.get("description", "").strip() or None,
        default_amount=request.form.get("default_amount", "0"),
        amount_type=request.form.get("amount_type", "fixed"),
        sort_order=int(request.form.get("sort_order") or 0),
        is_active=request.form.get("is_active") == "on",
    )
    db.session.add(entry)
    db.session.flush()
    for month in Month.query.order_by(Month.year.asc(), Month.month.asc()).all():
        db.session.add(
            MonthlyEntryValue(
                month_id=month.id,
                entry_id=entry.id,
                planned_amount=entry.default_amount,
            )
        )
    db.session.commit()
    flash("Eintrag angelegt und in vorhandene Monate übernommen.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/entries/<int:entry_id>", methods=["POST"])
@login_required
@admin_required
def update_entry(entry_id: int):
    entry = Entry.query.get_or_404(entry_id)
    name = request.form["name"].strip()
    entry.category_id = int(request.form["category_id"])
    entry.name = name
    entry.slug = slugify(request.form.get("slug", "") or name)
    entry.description = request.form.get("description", "").strip() or None
    entry.default_amount = request.form.get("default_amount", "0")
    entry.amount_type = request.form.get("amount_type", "fixed")
    entry.sort_order = int(request.form.get("sort_order") or 0)
    entry.is_active = request.form.get("is_active") == "on"
    db.session.commit()
    flash("Eintrag aktualisiert.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/entries/<int:entry_id>/share-rules", methods=["POST"])
@login_required
@admin_required
def create_share_rule(entry_id: int):
    participant_id = int(request.form["participant_id"])
    rule = EntryShareRule.query.filter_by(entry_id=entry_id, participant_id=participant_id).first()
    if rule is None:
        rule = EntryShareRule(entry_id=entry_id, participant_id=participant_id)
        db.session.add(rule)
    rule.share_type = request.form.get("share_type", "equal")
    share_value = request.form.get("share_value", "").strip()
    rule.share_value = share_value or None
    db.session.commit()
    flash("Beteiligungsregel gespeichert.", "success")
    return redirect(url_for("admin.index"))


@admin_bp.route("/share-rules/<int:rule_id>/delete", methods=["POST"])
@login_required
@admin_required
def delete_share_rule(rule_id: int):
    rule = EntryShareRule.query.get_or_404(rule_id)
    db.session.delete(rule)
    db.session.commit()
    flash("Beteiligungsregel entfernt.", "info")
    return redirect(url_for("admin.index"))