from django.shortcuts import render, get_object_or_404
from django.contrib.auth.decorators import login_required
from django.views.decorators.http import require_http_methods
from django.http import HttpRequest, HttpResponse, Http404
from django.template.loader import render_to_string
from django.core.exceptions import PermissionDenied

from .models import ChangeSet, CommentThread, Comment
from .notifications import NotificationDispatcher
from .state_machine import ApprovalStateMachine

@login_required
def get_comments(request: HttpRequest) -> HttpResponse:
    """HTMX endpoint to get comments for a specific anchor"""
    anchor = request.GET.get('anchor')
    if not anchor:
        raise Http404("Anchor parameter is required")

    thread = CommentThread.objects.filter(anchor__id=anchor).first()
    comments = thread.comments.all() if thread else []

    return render(request, 'history_tracking/partials/comments_list.html', {
        'comments': comments,
        'anchor': anchor
    })

@login_required
@require_http_methods(["POST"])
def preview_comment(request: HttpRequest) -> HttpResponse:
    """HTMX endpoint for live comment preview"""
    content = request.POST.get('content', '')
    return render(request, 'history_tracking/partials/comment_preview.html', {
        'content': content
    })

@login_required
@require_http_methods(["POST"])
def add_comment(request: HttpRequest) -> HttpResponse:
    """HTMX endpoint to add a comment"""
    anchor = request.POST.get('anchor')
    content = request.POST.get('content')
    parent_id = request.POST.get('parent_id')

    if not content:
        return HttpResponse("Comment content is required", status=400)

    thread, created = CommentThread.objects.get_or_create(
        anchor={'id': anchor},
        defaults={'created_by': request.user}
    )

    comment = thread.comments.create(
        author=request.user,
        content=content,
        parent_id=parent_id if parent_id else None
    )

    comment.extract_mentions()

    # Send notifications
    dispatcher = NotificationDispatcher()
    dispatcher.notify_new_comment(comment, thread)

    # Return updated comments list
    return render(request, 'history_tracking/partials/comments_list.html', {
        'comments': thread.comments.all(),
        'anchor': anchor
    })

@login_required
@require_http_methods(["POST"])
def approve_changes(request: HttpRequest, changeset_id: int) -> HttpResponse:
    """HTMX endpoint for approving/rejecting changes"""
    changeset = get_object_or_404(ChangeSet, pk=changeset_id)
    state_machine = ApprovalStateMachine(changeset)

    if not state_machine.can_user_approve(request.user):
        raise PermissionDenied("You don't have permission to approve these changes")

    decision = request.POST.get('decision', 'approve')
    comment = request.POST.get('comment', '')
    stage_id = request.POST.get('stage_id')

    success = state_machine.submit_approval(
        user=request.user,
        decision=decision,
        comment=comment,
        stage_id=stage_id
    )

    if not success:
        return HttpResponse("Failed to submit approval", status=400)

    # Return updated approval status
    return render(request, 'history_tracking/partials/approval_status.html', {
        'changeset': changeset,
        'current_stage': state_machine.get_current_stage(),
        'can_approve': state_machine.can_user_approve(request.user),
        'pending_approvers': state_machine.get_pending_approvers()
    })

@login_required
def approval_notifications(request: HttpRequest, changeset_id: int) -> HttpResponse:
    """HTMX endpoint for live approval notifications"""
    changeset = get_object_or_404(ChangeSet, pk=changeset_id)
    return render(request, 'history_tracking/partials/approval_notifications.html', {
        'notifications': changeset.get_recent_notifications()
    })

@login_required
def get_replies(request: HttpRequest, comment_id: int) -> HttpResponse:
    """HTMX endpoint to get comment replies"""
    comment = get_object_or_404(Comment, pk=comment_id)
    return render(request, 'history_tracking/partials/comment_replies.html', {
        'replies': comment.replies.all()
    })

@login_required
def reply_form(request: HttpRequest) -> HttpResponse:
    """HTMX endpoint to get the reply form template"""
    return render(request, 'history_tracking/partials/reply_form.html', {
        'parent_id': request.GET.get('parent_id')
    })