import uuid

import os

from flask import Blueprint, abort, current_app, flash, redirect, render_template, request, session, url_for
from flask_login import current_user, login_required, login_user

from ..extensions import db
from ..models import Company, Display, DisplaySession, Playlist, PlaylistItem, User

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


def admin_required():
    if not current_user.is_authenticated or not current_user.is_admin:
        abort(403)


def _try_delete_upload(file_path: str | None, upload_folder: str):
    """Best-effort delete of an uploaded media file."""
    if not file_path:
        return
    if not file_path.startswith("uploads/"):
        return

    filename = file_path.split("/", 1)[1]
    abs_path = os.path.join(upload_folder, filename)
    try:
        if os.path.isfile(abs_path):
            os.remove(abs_path)
    except Exception:
        # Ignore cleanup failures
        pass


@bp.get("/")
@login_required
def dashboard():
    admin_required()
    companies = Company.query.order_by(Company.name.asc()).all()
    users = User.query.order_by(User.username.asc()).all()
    return render_template("admin/dashboard.html", companies=companies, users=users)


@bp.post("/companies")
@login_required
def create_company():
    admin_required()
    name = request.form.get("name", "").strip()
    if not name:
        flash("Company name required", "danger")
        return redirect(url_for("admin.dashboard"))
    if Company.query.filter_by(name=name).first():
        flash("Company name already exists", "danger")
        return redirect(url_for("admin.dashboard"))
    c = Company(name=name)
    db.session.add(c)
    db.session.commit()
    flash("Company created", "success")
    return redirect(url_for("admin.company_detail", company_id=c.id))


@bp.get("/companies/<int:company_id>")
@login_required
def company_detail(company_id: int):
    admin_required()
    company = db.session.get(Company, company_id)
    if not company:
        abort(404)
    return render_template("admin/company_detail.html", company=company)


@bp.post("/companies/<int:company_id>/users")
@login_required
def create_company_user(company_id: int):
    admin_required()
    company = db.session.get(Company, company_id)
    if not company:
        abort(404)
    username = request.form.get("username", "").strip()
    email = (request.form.get("email", "") or "").strip().lower() or None
    password = request.form.get("password", "")
    if not username or not email or not password:
        flash("Username, email and password required", "danger")
        return redirect(url_for("admin.company_detail", company_id=company_id))
    if User.query.filter_by(username=username).first():
        flash("Username already exists", "danger")
        return redirect(url_for("admin.company_detail", company_id=company_id))

    if User.query.filter_by(email=email).first():
        flash("Email already exists", "danger")
        return redirect(url_for("admin.company_detail", company_id=company_id))

    u = User(username=username, is_admin=False, company=company)
    u.email = email
    u.set_password(password)
    db.session.add(u)
    db.session.commit()
    flash("User created", "success")
    return redirect(url_for("admin.company_detail", company_id=company_id))


@bp.post("/companies/<int:company_id>/displays")
@login_required
def create_display(company_id: int):
    admin_required()
    company = db.session.get(Company, company_id)
    if not company:
        abort(404)
    name = request.form.get("name", "").strip() or "Display"
    token = uuid.uuid4().hex
    d = Display(company=company, name=name, token=token)
    db.session.add(d)
    db.session.commit()
    flash("Display created", "success")
    return redirect(url_for("admin.company_detail", company_id=company_id))


@bp.post("/companies/<int:company_id>/delete")
@login_required
def delete_company(company_id: int):
    admin_required()

    company = db.session.get(Company, company_id)
    if not company:
        abort(404)

    # If FK constraints are enabled, we must delete in a safe order.
    # 1) Detach displays from playlists (Display.assigned_playlist_id -> Playlist.id)
    for d in list(company.displays):
        d.assigned_playlist_id = None

    # 2) Delete display sessions referencing displays of this company
    display_ids = [d.id for d in company.displays]
    if display_ids:
        DisplaySession.query.filter(DisplaySession.display_id.in_(display_ids)).delete(synchronize_session=False)

    # 3) Clean up uploaded media files for all playlist items
    upload_folder = current_app.config["UPLOAD_FOLDER"]
    items = (
        PlaylistItem.query.join(Playlist, PlaylistItem.playlist_id == Playlist.id)
        .filter(Playlist.company_id == company.id)
        .all()
    )
    for it in items:
        if it.item_type in ("image", "video"):
            _try_delete_upload(it.file_path, upload_folder)

    # 4) Delete the company; cascades will delete users/displays/playlists/items.
    company_name = company.name
    db.session.delete(company)
    db.session.commit()

    flash(f"Company '{company_name}' deleted (including users, displays and playlists).", "success")
    return redirect(url_for("admin.dashboard"))


@bp.post("/impersonate/<int:user_id>")
@login_required
def impersonate(user_id: int):
    admin_required()
    target = db.session.get(User, user_id)
    if not target or target.is_admin:
        flash("Cannot impersonate this user", "danger")
        return redirect(url_for("admin.dashboard"))

    # Save admin id in session so we can return without any password.
    session["impersonator_admin_id"] = current_user.id
    login_user(target)
    flash(f"Impersonating {target.username}.", "warning")
    return redirect(url_for("company.dashboard"))


@bp.post("/users/<int:user_id>/email")
@login_required
def update_user_email(user_id: int):
    admin_required()
    u = db.session.get(User, user_id)
    if not u:
        abort(404)

    email = (request.form.get("email", "") or "").strip().lower() or None
    if email:
        existing = User.query.filter(User.email == email, User.id != u.id).first()
        if existing:
            flash("Email already exists", "danger")
            return redirect(url_for("admin.company_detail", company_id=u.company_id))

    u.email = email
    db.session.commit()
    flash("Email updated", "success")
    return redirect(url_for("admin.company_detail", company_id=u.company_id))