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 ..uploads import abs_upload_path, ensure_company_upload_dir, get_company_upload_bytes, is_valid_upload_relpath
from ..models import AppSettings, Company, Display, DisplaySession, Playlist, PlaylistItem, User
from ..email_utils import send_email

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 _get_app_settings() -> AppSettings:
    """Get the singleton-ish AppSettings row, creating it if needed."""

    s = db.session.get(AppSettings, 1)
    if s:
        return s
    s = AppSettings(id=1)
    db.session.add(s)
    db.session.commit()
    return s


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 is_valid_upload_relpath(file_path):
        return

    abs_path = abs_upload_path(upload_folder, file_path)
    if not abs_path:
        return
    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()
    return render_template("admin/dashboard.html", companies=companies)


@bp.get("/settings")
@login_required
def settings():
    admin_required()
    settings = _get_app_settings()
    admins = User.query.filter_by(is_admin=True).order_by(User.email.asc()).all()
    return render_template("admin/settings.html", settings=settings, admins=admins)


@bp.post("/settings/smtp")
@login_required
def update_smtp_settings():
    admin_required()
    s = _get_app_settings()

    smtp_host = (request.form.get("smtp_host") or "").strip() or None
    smtp_port_raw = (request.form.get("smtp_port") or "").strip()
    smtp_username = (request.form.get("smtp_username") or "").strip() or None
    smtp_password = request.form.get("smtp_password")
    smtp_from = (request.form.get("smtp_from") or "").strip() or None
    smtp_starttls = (request.form.get("smtp_starttls") or "").lower() in ("1", "true", "yes", "on")
    smtp_debug = (request.form.get("smtp_debug") or "").lower() in ("1", "true", "yes", "on")
    smtp_timeout_raw = (request.form.get("smtp_timeout_seconds") or "").strip()

    smtp_port: int | None = None
    if smtp_port_raw:
        try:
            smtp_port = int(smtp_port_raw)
        except ValueError:
            flash("SMTP port must be a number", "danger")
            return redirect(url_for("admin.settings"))

    smtp_timeout: float = 10.0
    if smtp_timeout_raw:
        try:
            smtp_timeout = float(smtp_timeout_raw)
        except ValueError:
            flash("SMTP timeout must be a number (seconds)", "danger")
            return redirect(url_for("admin.settings"))

    if smtp_port is not None and (smtp_port <= 0 or smtp_port > 65535):
        flash("SMTP port must be between 1 and 65535", "danger")
        return redirect(url_for("admin.settings"))

    if smtp_timeout <= 0:
        flash("SMTP timeout must be > 0", "danger")
        return redirect(url_for("admin.settings"))

    s.smtp_host = smtp_host
    s.smtp_port = smtp_port
    s.smtp_username = smtp_username

    # Only overwrite password if a value was submitted.
    # This allows editing other SMTP fields without having to re-enter the password.
    if smtp_password is not None and smtp_password.strip() != "":
        s.smtp_password = smtp_password

    s.smtp_from = smtp_from
    s.smtp_starttls = smtp_starttls
    s.smtp_timeout_seconds = smtp_timeout
    s.smtp_debug = smtp_debug
    db.session.commit()

    flash("SMTP settings saved.", "success")
    return redirect(url_for("admin.settings"))


@bp.post("/settings/domain")
@login_required
def update_public_domain():
    admin_required()
    s = _get_app_settings()
    raw = (request.form.get("public_domain") or "").strip().lower()
    if raw:
        # Normalize: user asked for domain-only (no scheme). Strip possible scheme anyway.
        raw = raw.replace("http://", "").replace("https://", "")
        raw = raw.strip().strip("/")
        if "/" in raw:
            flash("Public domain must not contain a path. Example: signage.example.com", "danger")
            return redirect(url_for("admin.settings"))
        if " " in raw:
            flash("Public domain must not contain spaces", "danger")
            return redirect(url_for("admin.settings"))
        s.public_domain = raw
    else:
        s.public_domain = None
    db.session.commit()
    flash("Public domain saved.", "success")
    return redirect(url_for("admin.settings"))


@bp.post("/settings/test-email")
@login_required
def send_test_email():
    admin_required()
    to_email = (request.form.get("to_email") or "").strip().lower()
    if not to_email:
        flash("Test email recipient is required", "danger")
        return redirect(url_for("admin.settings"))

    try:
        send_email(
            to_email=to_email,
            subject="Signage SMTP test",
            body_text="This is a test email from Signage (Admin → Settings).",
        )
    except Exception as e:
        # Show a short error to the admin (they requested a test).
        flash(f"Failed to send test email: {e}", "danger")
        return redirect(url_for("admin.settings"))

    flash(f"Test email sent to {to_email}", "success")
    return redirect(url_for("admin.settings"))


@bp.post("/settings/admins")
@login_required
def create_admin_user():
    admin_required()
    email = (request.form.get("email") or "").strip().lower()
    password = request.form.get("password") or ""

    if not email or not password:
        flash("Email and password are required", "danger")
        return redirect(url_for("admin.settings"))

    if len(password) < 8:
        flash("Password must be at least 8 characters", "danger")
        return redirect(url_for("admin.settings"))

    existing = User.query.filter_by(email=email).first()
    if existing:
        if existing.is_admin:
            flash("That user is already an admin", "warning")
            return redirect(url_for("admin.settings"))
        # Promote existing user to admin
        existing.is_admin = True
        existing.set_password(password)
        existing.email = email
        existing.username = email
        existing.company_id = None
        db.session.commit()
        flash("User promoted to admin.", "success")
        return redirect(url_for("admin.settings"))

    u = User(is_admin=True)
    u.email = email
    u.username = email
    u.set_password(password)
    db.session.add(u)
    db.session.commit()
    flash("Admin user created.", "success")
    return redirect(url_for("admin.settings"))


@bp.post("/settings/admins/<int:user_id>/demote")
@login_required
def demote_admin_user(user_id: int):
    admin_required()
    if current_user.id == user_id:
        flash("You cannot demote yourself", "danger")
        return redirect(url_for("admin.settings"))

    u = db.session.get(User, user_id)
    if not u:
        abort(404)
    if not u.is_admin:
        flash("That user is not an admin", "warning")
        return redirect(url_for("admin.settings"))

    # Ensure we always keep at least one admin.
    admin_count = User.query.filter_by(is_admin=True).count()
    if admin_count <= 1:
        flash("Cannot demote the last remaining admin", "danger")
        return redirect(url_for("admin.settings"))

    u.is_admin = False
    db.session.commit()
    flash("Admin user demoted.", "success")
    return redirect(url_for("admin.settings"))


@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()

    # Create the per-company upload directory eagerly (best-effort).
    try:
        ensure_company_upload_dir(current_app.config["UPLOAD_FOLDER"], c.id)
    except Exception:
        # Upload directory is also created lazily on first upload.
        pass
    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)

    upload_root = current_app.config["UPLOAD_FOLDER"]
    used_bytes = get_company_upload_bytes(upload_root, company.id)

    return render_template(
        "admin/company_detail.html",
        company=company,
        storage={
            "used_bytes": used_bytes,
        },
    )


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

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

    raw = (request.form.get("storage_max_mb") or "").strip()
    if raw == "":
        # Treat empty as unlimited
        company.storage_max_bytes = None
        db.session.commit()
        flash("Storage limit cleared (unlimited).", "success")
        return redirect(url_for("admin.company_detail", company_id=company_id))

    try:
        mb = float(raw)
    except ValueError:
        flash("Invalid storage limit. Please enter a number (MB).", "danger")
        return redirect(url_for("admin.company_detail", company_id=company_id))

    if mb <= 0:
        company.storage_max_bytes = None
        db.session.commit()
        flash("Storage limit cleared (unlimited).", "success")
        return redirect(url_for("admin.company_detail", company_id=company_id))

    company.storage_max_bytes = int(mb * 1024 * 1024)
    db.session.commit()
    flash("Storage limit updated.", "success")
    return redirect(url_for("admin.company_detail", company_id=company_id))


@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)
    email = (request.form.get("email", "") or "").strip().lower() or None
    password = request.form.get("password", "")
    if not email or not password:
        flash("Email and password required", "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(is_admin=False, company=company)
    u.email = email
    u.username = 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.email or '(no email)'}.", "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()
    if not email:
        flash("Email is required", "danger")
        return redirect(url_for("admin.company_detail", company_id=u.company_id))

    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
    # keep backwards-compatible username column in sync
    u.username = email
    db.session.commit()
    flash("Email updated", "success")
    return redirect(url_for("admin.company_detail", company_id=u.company_id))


@bp.post("/users/<int:user_id>/delete")
@login_required
def delete_user(user_id: int):
    """Admin: delete a non-admin user."""

    admin_required()

    u = db.session.get(User, user_id)
    if not u:
        abort(404)

    # Safety checks
    if u.is_admin:
        flash("Cannot delete an admin user", "danger")
        return redirect(url_for("admin.dashboard"))

    if u.id == current_user.id:
        flash("You cannot delete yourself", "danger")
        return redirect(url_for("admin.dashboard"))

    company_id = u.company_id
    company_name = u.company.name if u.company else None
    email = u.email

    db.session.delete(u)
    db.session.commit()

    flash(
        f"User '{email}' deleted" + (f" from '{company_name}'." if company_name else "."),
        "success",
    )

    if company_id:
        return redirect(url_for("admin.company_detail", company_id=company_id))
    return redirect(url_for("admin.dashboard"))


@bp.post("/displays/<int:display_id>/name")
@login_required
def update_display_name(display_id: int):
    """Admin: rename a display."""
    admin_required()

    display = db.session.get(Display, display_id)
    if not display:
        abort(404)

    name = (request.form.get("name") or "").strip()
    if not name:
        flash("Display name is required", "danger")
        return redirect(url_for("admin.company_detail", company_id=display.company_id))

    display.name = name[:120]
    db.session.commit()
    flash("Display name updated", "success")
    return redirect(url_for("admin.company_detail", company_id=display.company_id))