from flask import (Blueprint, render_template, redirect, url_for,
                   flash, request, abort)
from flask_login import login_required, current_user
from flask_wtf import FlaskForm
from wtforms import (StringField, PasswordField, SelectField,
                     BooleanField, SubmitField, TextAreaField)
from wtforms.validators import DataRequired, Email, Length, Optional, EqualTo, ValidationError

from app.extensions import db, bcrypt
from app.models.user import User
from app.models.resource import Resource
from app.models.setting import SystemSetting
from app.utils.decorators import admin_required

admin_bp = Blueprint('admin', __name__)


# ── 表单 ─────────────────────────────────────────────────────────────────────

class UserCreateForm(FlaskForm):
    username = StringField('用户名', validators=[DataRequired(), Length(3, 64)])
    email = StringField('邮箱', validators=[DataRequired(), Email()])
    password = PasswordField('密码', validators=[DataRequired(), Length(min=8)])
    role = SelectField('角色', choices=[('user', '普通用户'), ('admin', '管理员')])
    is_active = BooleanField('启用账号', default=True)
    submit = SubmitField('创建')

    def validate_username(self, field):
        if User.query.filter_by(username=field.data).first():
            raise ValidationError('用户名已存在')

    def validate_email(self, field):
        if User.query.filter_by(email=field.data).first():
            raise ValidationError('邮箱已被使用')


class UserEditForm(FlaskForm):
    username = StringField('用户名', validators=[DataRequired(), Length(3, 64)])
    email = StringField('邮箱', validators=[DataRequired(), Email()])
    password = PasswordField('新密码（留空不修改）', validators=[Optional(), Length(min=8)])
    role = SelectField('角色', choices=[('user', '普通用户'), ('admin', '管理员')])
    is_active = BooleanField('启用账号')
    submit = SubmitField('保存')


class SettingForm(FlaskForm):
    site_name = StringField('站点名称', validators=[DataRequired()])
    site_description = TextAreaField('站点描述')
    allow_register = BooleanField('允许用户自行注册')
    max_upload_mb = StringField('最大上传大小(MB)', validators=[DataRequired()])
    enable_url_download = BooleanField('启用 URL 下载')
    enable_magnet = BooleanField('启用磁力下载')
    submit = SubmitField('保存设置')


# ── 路由 ─────────────────────────────────────────────────────────────────────

@admin_bp.route('/')
@login_required
@admin_required
def dashboard():
    total_users = User.query.count()
    total_resources = Resource.query.count()
    recent_users = User.query.order_by(User.created_at.desc()).limit(5).all()
    recent_resources = Resource.query.order_by(Resource.created_at.desc()).limit(10).all()
    type_stats = {}
    for t in ('text', 'image', 'audio', 'video'):
        type_stats[t] = Resource.query.filter_by(resource_type=t).count()
    return render_template('admin/dashboard.html',
                           total_users=total_users,
                           total_resources=total_resources,
                           recent_users=recent_users,
                           recent_resources=recent_resources,
                           type_stats=type_stats)


# ─── 用户管理 ─────────────────────────────────────────────────────────────────

@admin_bp.route('/users')
@login_required
@admin_required
def users():
    page = request.args.get('page', 1, type=int)
    q = request.args.get('q', '')
    query = User.query
    if q:
        query = query.filter(
            User.username.ilike(f'%{q}%') | User.email.ilike(f'%{q}%')
        )
    pagination = query.order_by(User.created_at.desc()).paginate(
        page=page, per_page=20, error_out=False)
    return render_template('admin/users.html',
                           pagination=pagination, q=q)


@admin_bp.route('/users/create', methods=['GET', 'POST'])
@login_required
@admin_required
def user_create():
    form = UserCreateForm()
    if form.validate_on_submit():
        pw_hash = bcrypt.generate_password_hash(form.password.data).decode('utf-8')
        user = User(
            username=form.username.data,
            email=form.email.data,
            password_hash=pw_hash,
            role=form.role.data,
            is_active=form.is_active.data
        )
        db.session.add(user)
        db.session.commit()
        flash(f'用户 {user.username} 创建成功', 'success')
        return redirect(url_for('admin.users'))
    return render_template('admin/user_form.html', form=form,
                           title='创建用户', action='create')


@admin_bp.route('/users/<int:user_id>/edit', methods=['GET', 'POST'])
@login_required
@admin_required
def user_edit(user_id):
    user = db.get_or_404(User, user_id)
    form = UserEditForm(obj=user)
    if form.validate_on_submit():
        # 检查用户名/邮箱唯一性
        dup_name = User.query.filter(
            User.username == form.username.data, User.id != user_id).first()
        dup_email = User.query.filter(
            User.email == form.email.data, User.id != user_id).first()
        if dup_name:
            flash('用户名已存在', 'danger')
        elif dup_email:
            flash('邮箱已被使用', 'danger')
        else:
            user.username = form.username.data
            user.email = form.email.data
            user.role = form.role.data
            user.is_active = form.is_active.data
            if form.password.data:
                user.password_hash = bcrypt.generate_password_hash(
                    form.password.data).decode('utf-8')
            db.session.commit()
            flash('用户信息已更新', 'success')
            return redirect(url_for('admin.users'))
    return render_template('admin/user_form.html', form=form,
                           title='编辑用户', action='edit', user=user)


@admin_bp.route('/users/<int:user_id>/toggle', methods=['POST'])
@login_required
@admin_required
def user_toggle(user_id):
    user = db.get_or_404(User, user_id)
    if user.id == current_user.id:
        flash('不能禁用自己的账号', 'warning')
    else:
        user.is_active = not user.is_active
        db.session.commit()
        status = '启用' if user.is_active else '禁用'
        flash(f'账号已{status}', 'success')
    return redirect(url_for('admin.users'))


@admin_bp.route('/users/<int:user_id>/delete', methods=['POST'])
@login_required
@admin_required
def user_delete(user_id):
    user = db.get_or_404(User, user_id)
    if user.id == current_user.id:
        flash('不能删除自己的账号', 'warning')
    else:
        db.session.delete(user)
        db.session.commit()
        flash(f'用户 {user.username} 已删除', 'success')
    return redirect(url_for('admin.users'))


# ─── 系统设置 ─────────────────────────────────────────────────────────────────

@admin_bp.route('/settings', methods=['GET', 'POST'])
@login_required
@admin_required
def settings():
    form = SettingForm()

    if form.validate_on_submit():
        SystemSetting.set('site_name', form.site_name.data)
        SystemSetting.set('site_description', form.site_description.data)
        SystemSetting.set('allow_register',
                          'true' if form.allow_register.data else 'false')
        SystemSetting.set('max_upload_mb', form.max_upload_mb.data)
        SystemSetting.set('enable_url_download',
                          'true' if form.enable_url_download.data else 'false')
        SystemSetting.set('enable_magnet',
                          'true' if form.enable_magnet.data else 'false')
        flash('设置已保存', 'success')
        return redirect(url_for('admin.settings'))

    # 填充表单当前值
    form.site_name.data = SystemSetting.get('site_name', '个人资料库')
    form.site_description.data = SystemSetting.get('site_description', '')
    form.allow_register.data = SystemSetting.get('allow_register', 'true') == 'true'
    form.max_upload_mb.data = SystemSetting.get('max_upload_mb', '500')
    form.enable_url_download.data = SystemSetting.get('enable_url_download', 'true') == 'true'
    form.enable_magnet.data = SystemSetting.get('enable_magnet', 'true') == 'true'

    return render_template('admin/settings.html', form=form)