from functools import wraps
from flask import render_template, url_for, request
from flask_login import current_user


def get_params(*args):
    """Helper to get parameters from kwargs, form, or args."""
    res = []
    for arg in args:
        val = request.view_args.get(arg)
        if val is None:
            val = request.form.get(arg, type=int)
        if val is None:
            val = request.args.get(arg, type=int)
        res.append(val)
    return res[0] if len(res) == 1 else tuple(res)


def get_person_id_from_context():
    """Helper to find person_id from URL/form context."""
    person_id, workout_id, topset_id = get_params('person_id', 'workout_id', 'topset_id')
    
    from app import db
    if person_id is not None:
        return person_id
        
    if workout_id is not None:
        workout_info = db.execute("SELECT person_id FROM workout WHERE workout_id = %s", [workout_id], one=True)
        if workout_info:
            return workout_info['person_id']
            
    if topset_id is not None:
        topset_info = db.execute("SELECT workout_id FROM topset WHERE topset_id = %s", [topset_id], one=True)
        if topset_info:
            w_id = topset_info['workout_id']
            workout_info = db.execute("SELECT person_id FROM workout WHERE workout_id = %s", [w_id], one=True)
            if workout_info:
                return workout_info['person_id']
                
    return None


def validate_person(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        person_id = get_params('person_id')
        from app import db
        person = db.is_valid_person(person_id)
        if person is None:
            return render_template('error.html', error='404', message=f'Unable to find Person({person_id})', url='/')
        return func(*args, **kwargs)
    return wrapper


def validate_workout(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        person_id, workout_id = get_params('person_id', 'workout_id')
        from app import db
        if person_id is None and workout_id is not None:
             person_id = get_person_id_from_context()

        workout = db.is_valid_workout(person_id, workout_id)
        if workout is None:
            return render_template('error.html', error='404', message=f'Unable to find Workout({workout_id}) completed by Person({person_id})', url=url_for('person_overview', person_id=person_id) if person_id else '/')
        return func(*args, **kwargs)
    return wrapper


def validate_topset(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        person_id, workout_id, topset_id = get_params('person_id', 'workout_id', 'topset_id')
        from app import db
        if (person_id is None or workout_id is None) and topset_id is not None:
             person_id = get_person_id_from_context()
             # We could also find workout_id, but is_valid_topset handles it if we have at least topset_id

        topset = db.is_valid_topset(person_id, workout_id, topset_id)
        if topset is None:
             fallback_url = url_for('person_overview', person_id=person_id) if person_id else '/'
             return render_template('error.html', error='404', message=f'Unable to find TopSet({topset_id})', url=fallback_url)
        return func(*args, **kwargs)
    return wrapper


ACTION_MAP = {
    'workout.create_workout': 'create a workout',
    'workout.delete_workout': 'delete this workout',
    'workout.update_workout_start_date': 'change the date for this workout',
    'workout.create_topset': 'add a set',
    'workout.update_topset': 'update this set',
    'workout.delete_topset': 'delete this set',
    'delete_person': 'delete this person',
    'update_person_name': 'update this person\'s name',
    'tags.add_tag': 'add a tag',
    'tags.delete_tag': 'delete this tag',
    'tags.add_tag_to_workout': 'add a tag to this workout',
    'tags.create_new_tag_for_workout': 'create a new tag for this workout',
    'workout.create_program': 'create a workout program',
    'programs.delete_program': 'delete this workout program',
    'delete_exercise': 'delete an exercise',
    'delete_person': 'delete a user',
}


def admin_required(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        if not current_user.is_authenticated or not getattr(current_user, 'is_admin', False):
            from flask import flash
            msg = "You must be an admin to perform this action."
            if request.endpoint in ACTION_MAP:
                msg = f"You must be an admin to {ACTION_MAP[request.endpoint]}."
            
            flash(msg, "warning")
            if request.headers.get('HX-Request'):
                return '', 200, {'HX-Redirect': url_for('dashboard')}
            return render_template('error.html', error='403', message=msg, url='/')
        return func(*args, **kwargs)
    return wrapper


def get_auth_message(endpoint, person_id=None, is_authenticated=False):
    """Generates a friendly authorization message."""
    action = ACTION_MAP.get(endpoint)
    if not action:
        # Fallback: prettify endpoint name if not in map
        # e.g. 'workout.create_topset' -> 'create topset'
        action = endpoint.split('.')[-1].replace('_', ' ')
    
    if is_authenticated:
        msg = f"You are not authorized to {action}"
    else:
        msg = f"Please log in to {action}"

    if person_id:
        from app import db
        person_name = db.get_person_name(person_id)
        if person_name:
            msg += f" for {person_name}"
    return msg


def require_ownership(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        person_id = get_person_id_from_context()
        
        # Authorization check: must be logged in and (the owner or an admin)
        is_admin = getattr(current_user, 'is_admin', False)
        if not current_user.is_authenticated or (person_id is not None and int(current_user.get_id()) != person_id and not is_admin):
            from flask import flash
            msg = get_auth_message(request.endpoint, person_id, is_authenticated=current_user.is_authenticated)
            flash(msg, "info")
            
            if request.headers.get('HX-Request'):
                return '', 200, {'HX-Redirect': url_for('auth.login') if not current_user.is_authenticated else url_for('dashboard')}
            return render_template('error.html', error='403', message='You are not authorized to modify this resource.', url='/')
            
        return func(*args, **kwargs)
    return wrapper