import os
import platform

from django.shortcuts import render, redirect, get_object_or_404
from django.utils import timezone
from .models import Profile, Intent, ValueTag, Message, Post, Comment, Reaction, HiddenPost, Follow
from django.contrib.auth.models import User
from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth import login
from django.contrib.auth.decorators import login_required
from django.db.models import Q

def home(request):
    """Render the landing screen or member dashboard."""
    
    # Simple logic to seed data for the first run
    if not Intent.objects.exists():
        intents_data = [
            ('Friendship', 'bi-people'),
            ('Networking', 'bi-briefcase'),
            ('Activity Partner', 'bi-bicycle'),
            ('Accountability', 'bi-check-circle')
        ]
        for name, icon in intents_data:
            Intent.objects.create(name=name, icon=icon)
            
    if not Profile.objects.exists():
        # Create a demo user/profile
        demo_user, _ = User.objects.get_or_create(username='marcus_v', first_name='Marcus', last_name='V.')
        p = Profile.objects.create(
            user=demo_user,
            professional_headline='Architect & Urban Planner',
            transition_status='new-in-town',
            bio='Passionate about sustainable cities. Recently moved here from Chicago and looking for local communities.',
            location_city='Austin, TX',
        )
        p.intents.add(Intent.objects.get(name='Networking'))
        
        demo_user2, _ = User.objects.get_or_create(username='sarah_l', first_name='Sarah', last_name='L.')
        p2 = Profile.objects.create(
            user=demo_user2,
            professional_headline='UX Researcher | Growth Mindset',
            transition_status='post-divorce',
            bio='Rediscovering my love for hiking and photography. Seeking authentic connections and shared growth.',
            location_city='Austin, TX',
        )
        p2.intents.add(Intent.objects.get(name='Friendship'))

    # Social Feed Logic
    hidden_post_ids = []
    if request.user.is_authenticated:
        hidden_post_ids = HiddenPost.objects.filter(user=request.user).values_list('post_id', flat=True)
    
    posts = Post.objects.exclude(id__in=hidden_post_ids).select_related('author', 'author__profile').prefetch_related('comments', 'comments__author', 'reactions')

    # Filtering by intent (for discovery)
    intent_filter = request.GET.get('intent')
    if intent_filter:
        profiles = Profile.objects.filter(intents__name__iexact=intent_filter)
    else:
        profiles = Profile.objects.all()

    intents = Intent.objects.all()

    # Dashboard logic for logged-in users
    stats = {}
    suggested_members = []
    suggested_events = []
    following_ids = []
    if request.user.is_authenticated:
        # Quick Stats
        stats = {
            'unread_messages': Message.objects.filter(recipient=request.user, is_read=False).count(),
            'pending_connections': 0, # Placeholder until connection request system exists
            'upcoming_events_count': request.user.attending_events.filter(start_time__gt=timezone.now()).count(),
            'completion_percentage': request.user.profile.profile_completion_percentage,
            'streak': request.user.profile.accountability_streak,
            'followers_count': request.user.profile.followers_count,
            'following_count': request.user.profile.following_count,
        }

        following_ids = list(Follow.objects.filter(follower=request.user).values_list('followed_id', flat=True))

        # Suggestions: Aligned members (shared intents or values)
        user_intents = request.user.profile.intents.all()
        user_values = request.user.profile.value_tags.all()
        suggested_members = Profile.objects.filter(
            Q(intents__in=user_intents) | Q(value_tags__in=user_values)
        ).exclude(user=request.user).distinct()[:10]

        # Suggested Events: Upcoming events
        from .models import Event
        suggested_events = Event.objects.filter(start_time__gt=timezone.now()).order_by('start_time')[:5]

    context = {
        "project_name": "CommonGround",
        "profiles": profiles,
        "intents": intents,
        "current_intent": intent_filter,
        "current_time": timezone.now(),
        "posts": posts,
        "stats": stats,
        "suggested_members": suggested_members,
        "suggested_events": suggested_events,
        "post_types": Post.POST_TYPE_CHOICES,
        "following_ids": following_ids,
    }
    return render(request, "core/index.html", context)

@login_required
def create_post(request):
    if request.method == 'POST':
        content = request.POST.get('content')
        image = request.FILES.get('image')
        post_type = request.POST.get('post_type', 'reflection')
        if content or image:
            Post.objects.create(author=request.user, content=content, image=image, post_type=post_type)
    return redirect('home')

@login_required
def delete_post(request, post_id):
    post = get_object_or_404(Post, id=post_id, author=request.user)
    post.delete()
    return redirect(request.META.get('HTTP_REFERER', 'home'))

@login_required
def add_comment(request, post_id):
    if request.method == 'POST':
        post = get_object_or_404(Post, id=post_id)
        content = request.POST.get('content')
        if content:
            Comment.objects.create(post=post, author=request.user, content=content)
    return redirect(request.META.get('HTTP_REFERER', 'home'))

@login_required
def toggle_reaction(request, post_id):
    post = get_object_or_404(Post, id=post_id)
    reaction_type = request.GET.get('type', 'heart')
    reaction, created = Reaction.objects.get_or_create(
        post=post, user=request.user, reaction_type=reaction_type
    )
    if not created:
        reaction.delete()
    return redirect(request.META.get('HTTP_REFERER', 'home'))

@login_required
def toggle_follow(request, username):
    target_user = get_object_or_404(User, username=username)
    if target_user == request.user:
        return redirect(request.META.get('HTTP_REFERER', 'home'))
    
    follow, created = Follow.objects.get_or_create(follower=request.user, followed=target_user)
    if not created:
        follow.delete()
    
    return redirect(request.META.get('HTTP_REFERER', 'home'))

@login_required
def hide_post(request, post_id):
    post = get_object_or_404(Post, id=post_id)
    HiddenPost.objects.get_or_create(user=request.user, post=post)
    return redirect('home')

def about(request):
    return render(request, "core/about.html")

def signup(request):
    if request.method == 'POST':
        form = UserCreationForm(request.POST)
        if form.is_valid():
            user = form.save()
            # Create profile
            Profile.objects.create(user=user)
            login(request, user)
            return redirect('onboarding')
    else:
        form = UserCreationForm()
    return render(request, 'registration/signup.html', {'form': form})

@login_required
def onboarding(request):
    # Simplified onboarding for MVP
    profile = request.user.profile
    if request.method == 'POST':
        profile.professional_headline = request.POST.get('headline', '')
        profile.bio = request.POST.get('bio', '')
        profile.onboarding_completed = True
        profile.save()
        return redirect('home')
    return render(request, 'core/onboarding.html', {'profile': profile})

@login_required
def settings_view(request):
    profile = request.user.profile
    if request.method == 'POST':
        profile.two_factor_enabled = 'two_factor' in request.POST
        profile.save()
        # In a real app we'd save more settings here
        return redirect('settings')
    return render(request, 'core/settings.html', {'profile': profile})

def get_started(request):
    if not request.user.is_authenticated:
        return redirect('signup')
    if not request.user.profile.onboarding_completed:
        return redirect('onboarding')
    return redirect('home')

@login_required
def inbox(request):
    # Get all users the current user has messaged or received messages from
    sent_to = Message.objects.filter(sender=request.user).values_list('recipient', flat=True)
    received_from = Message.objects.filter(recipient=request.user).values_list('sender', flat=True)
    
    partner_ids = set(list(sent_to) + list(received_from))
    partners = User.objects.filter(id__in=partner_ids).select_related('profile')
    
    # Add last message to each partner for display
    for partner in partners:
        last_message = Message.objects.filter(
            Q(sender=request.user, recipient=partner) | 
            Q(sender=partner, recipient=request.user)
        ).order_by('-timestamp').first()
        partner.last_message = last_message

    return render(request, 'core/inbox.html', {'partners': partners})

@login_required
def chat_detail(request, username):
    partner = get_object_or_404(User, username=username)
    if partner == request.user:
        return redirect('inbox')
        
    if request.method == 'POST':
        body = request.POST.get('body')
        if body:
            Message.objects.create(sender=request.user, recipient=partner, body=body)
            return redirect('chat_detail', username=username)
            
    messages = Message.objects.filter(
        Q(sender=request.user, recipient=partner) | 
        Q(sender=partner, recipient=request.user)
    ).order_by('timestamp')
    
    # Mark as read
    messages.filter(recipient=request.user, is_read=False).update(is_read=True)
    
    return render(request, 'core/chat.html', {
        'partner': partner,
        'chat_messages': messages
    })

@login_required
def profile_view(request):
    """Redirect to the current user's profile detail page."""
    return redirect('profile_detail', username=request.user.username)

def profile_detail(request, username):
    """View a user's profile."""
    target_user = get_object_or_404(User, username=username)
    is_following = False
    if request.user.is_authenticated:
        is_following = Follow.objects.filter(follower=request.user, followed=target_user).exists()
    return render(request, 'core/profile_detail.html', {
        'target_user': target_user,
        'is_following': is_following
    })

@login_required
def edit_profile(request):
    """Edit the current user's profile."""
    profile = request.user.profile
    if request.method == 'POST':
        profile.professional_headline = request.POST.get('headline', '')
        profile.bio = request.POST.get('bio', '')
        profile.location_city = request.POST.get('location', '')
        
        if 'avatar' in request.FILES:
            profile.avatar = request.FILES['avatar']
            
        profile.save()
        return redirect('my_profile')
        
    return render(request, 'core/edit_profile.html', {'profile': profile})