"""
QI Projects Console UI views

Provides full CRUD functionality for Quality Improvement projects,
task management, and template handling.
"""

from django.contrib import messages
from django.contrib.auth.decorators import login_required
from django.core.paginator import Paginator
from django.db.models import Q
from django.shortcuts import get_object_or_404, redirect, render
from django.utils.translation import gettext_lazy as _

from apps.core.decorators import block_source_user
from apps.organizations.models import Hospital
from apps.px_action_center.models import PXAction

from .forms import ConvertToProjectForm, QIProjectForm, QIProjectTaskForm, QIProjectTemplateForm, TaskTemplateFormSet
from .models import QIProject, QIProjectTask


@block_source_user
@login_required
def project_list(request):
    """QI Projects list view with filtering and pagination"""
    # Exclude templates from the list
    queryset = (
        QIProject.objects.filter(is_template=False)
        .select_related("hospital", "department", "project_lead")
        .prefetch_related("team_members", "related_actions")
    )

    # Apply RBAC filters
    user = request.user
    # Get selected hospital for PX Admins (from middleware)
    selected_hospital = getattr(request, "tenant_hospital", None)

    if user.is_px_admin():
        # PX Admins see all, but filter by selected hospital if set
        if selected_hospital:
            queryset = queryset.filter(hospital=selected_hospital)
    elif user.hospital:
        queryset = queryset.filter(hospital=user.hospital)

    # Apply filters
    status_filter = request.GET.get("status")
    if status_filter:
        queryset = queryset.filter(status=status_filter)

    hospital_filter = request.GET.get("hospital")
    if hospital_filter:
        queryset = queryset.filter(hospital_id=hospital_filter)

    # Search
    search_query = request.GET.get("search")
    if search_query:
        queryset = queryset.filter(
            Q(name__icontains=search_query)
            | Q(description__icontains=search_query)
            | Q(name_ar__icontains=search_query)
        )

    # Ordering
    queryset = queryset.order_by("-created_at")

    # Pagination
    page_size = int(request.GET.get("page_size", 25))
    paginator = Paginator(queryset, page_size)
    page_number = request.GET.get("page", 1)
    page_obj = paginator.get_page(page_number)

    # Get hospitals for filter
    hospitals = Hospital.objects.filter(status="active")
    if not user.is_px_admin() and user.hospital:
        hospitals = hospitals.filter(id=user.hospital.id)

    # Statistics
    stats = {
        "total": queryset.count(),
        "active": queryset.filter(status="active").count(),
        "completed": queryset.filter(status="completed").count(),
        "pending": queryset.filter(status="pending").count(),
    }

    context = {
        "page_obj": page_obj,
        "projects": page_obj.object_list,
        "stats": stats,
        "filters": request.GET,
    }

    return render(request, "projects/project_list.html", context)


@block_source_user
@login_required
def project_detail(request, pk):
    """QI Project detail view with task management"""
    project = get_object_or_404(
        QIProject.objects.filter(is_template=False)
        .select_related("hospital", "department", "project_lead")
        .prefetch_related("team_members", "related_actions", "tasks"),
        pk=pk,
    )

    # Check permission
    user = request.user
    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to view this project."))
        return redirect("projects:project_list")

    # Get tasks
    tasks = project.tasks.all().order_by("order", "created_at")

    # Get related actions
    related_actions = project.related_actions.all()

    context = {
        "project": project,
        "tasks": tasks,
        "related_actions": related_actions,
        "can_edit": user.is_px_admin() or user.is_hospital_admin or user.is_department_manager,
    }

    return render(request, "projects/project_detail.html", context)


@block_source_user
@login_required
def project_create(request, template_pk=None):
    """Create a new QI Project"""
    user = request.user

    # Check permission (PX Admin, Hospital Admin, or Department Manager)
    if not (user.is_px_admin() or user.is_hospital_admin or user.is_department_manager):
        messages.error(request, _("You don't have permission to create projects."))
        return redirect("projects:project_list")

    # Check for template parameter (from URL or GET)
    template_id = template_pk or request.GET.get("template")
    initial_data = {}
    template = None

    if template_id:
        try:
            template = QIProject.objects.get(pk=template_id, is_template=True)
            initial_data = {
                "name": template.name,
                "name_ar": template.name_ar,
                "description": template.description,
                "department": template.department,
                "target_completion_date": template.target_completion_date,
            }
            if not user.is_px_admin() and user.hospital:
                initial_data["hospital"] = user.hospital
        except QIProject.DoesNotExist:
            pass

    # Check for PX Action parameter (convert action to project)
    action_id = request.GET.get("action")
    if action_id:
        try:
            action = PXAction.objects.get(pk=action_id)
            initial_data["name"] = f"QI Project: {action.title}"
            initial_data["description"] = action.description
            if not user.is_px_admin() and user.hospital:
                initial_data["hospital"] = user.hospital
            else:
                initial_data["hospital"] = action.hospital
        except PXAction.DoesNotExist:
            pass

    if request.method == "POST":
        form = QIProjectForm(request.POST, request=request)

        # Check for template in POST data (hidden field)
        template_id_post = request.POST.get("template_id")
        if template_id_post:
            try:
                template = QIProject.objects.get(pk=template_id_post, is_template=True)
            except QIProject.DoesNotExist:
                template = None

        if form.is_valid():
            project = form.save(commit=False)
            project.created_by = user
            project.save()
            form.save_m2m()  # Save many-to-many relationships

            # If created from template, copy tasks
            task_count = 0
            if template:
                for template_task in template.tasks.all():
                    QIProjectTask.objects.create(
                        project=project,
                        title=template_task.title,
                        description=template_task.description,
                        order=template_task.order,
                        status="pending",
                    )
                    task_count += 1

            # If created from action, link it
            if action_id:
                try:
                    action = PXAction.objects.get(pk=action_id)
                    project.related_actions.add(action)
                except PXAction.DoesNotExist:
                    pass

            if template and task_count > 0:
                messages.success(
                    request,
                    _("QI Project created successfully with %(count)d task(s) from template.") % {"count": task_count},
                )
            else:
                messages.success(request, _("QI Project created successfully."))
            return redirect("projects:project_detail", pk=project.pk)
    else:
        form = QIProjectForm(request=request, initial=initial_data)

    context = {
        "form": form,
        "is_create": True,
        "template": template,
    }

    return render(request, "projects/project_form.html", context)


@block_source_user
@login_required
def project_edit(request, pk):
    """Edit an existing QI Project"""
    user = request.user
    project = get_object_or_404(QIProject, pk=pk, is_template=False)

    # Check permission
    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to edit this project."))
        return redirect("projects:project_list")

    # Check edit permission (PX Admin, Hospital Admin, or Department Manager)
    if not (user.is_px_admin() or user.is_hospital_admin or user.is_department_manager):
        messages.error(request, _("You don't have permission to edit projects."))
        return redirect("projects:project_detail", pk=project.pk)

    if request.method == "POST":
        form = QIProjectForm(request.POST, instance=project, request=request)
        if form.is_valid():
            form.save()
            messages.success(request, _("QI Project updated successfully."))
            return redirect("projects:project_detail", pk=project.pk)
    else:
        form = QIProjectForm(instance=project, request=request)

    context = {
        "form": form,
        "project": project,
        "is_create": False,
    }

    return render(request, "projects/project_form.html", context)


@block_source_user
@login_required
def project_delete(request, pk):
    """Delete a QI Project"""
    user = request.user
    project = get_object_or_404(QIProject, pk=pk, is_template=False)

    # Check permission (only PX Admin or Hospital Admin can delete)
    if not (user.is_px_admin() or user.is_hospital_admin):
        messages.error(request, _("You don't have permission to delete projects."))
        return redirect("projects:project_detail", pk=project.pk)

    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to delete this project."))
        return redirect("projects:project_list")

    if request.method == "POST":
        project_name = project.name
        project.delete()
        messages.success(request, _('Project "%(name)s" deleted successfully.') % {"name": project_name})
        return redirect("projects:project_list")

    context = {
        "project": project,
    }

    return render(request, "projects/project_delete_confirm.html", context)


@block_source_user
@login_required
def project_save_as_template(request, pk):
    """Save an existing project and its tasks as a template"""
    user = request.user
    project = get_object_or_404(QIProject, pk=pk, is_template=False)

    # Check permission (only PX Admin or Hospital Admin can create templates)
    if not (user.is_px_admin() or user.is_hospital_admin):
        messages.error(request, _("You don't have permission to create templates."))
        return redirect("projects:project_detail", pk=project.pk)

    # Check hospital access
    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to create templates from this project."))
        return redirect("projects:project_list")

    if request.method == "POST":
        template_name = request.POST.get("template_name", "").strip()
        template_description = request.POST.get("template_description", "").strip()
        make_global = request.POST.get("make_global") == "on"

        if not template_name:
            messages.error(request, _("Please provide a template name."))
            return redirect("projects:project_save_as_template", pk=project.pk)

        # Create template from project
        template = QIProject.objects.create(
            name=template_name,
            name_ar=template_name,  # Can be edited later
            description=template_description or project.description,
            is_template=True,
            # If global, hospital is None; otherwise use project's hospital
            hospital=None if make_global else project.hospital,
            department=project.department,
            status="pending",  # Default status for templates
            created_by=user,
        )

        # Copy tasks from project to template
        for task in project.tasks.all():
            QIProjectTask.objects.create(
                project=template,
                title=task.title,
                description=task.description,
                order=task.order,
                status="pending",  # Reset status for template
            )

        messages.success(
            request,
            _('Template "%(name)s" created successfully with %(count)d task(s).')
            % {"name": template_name, "count": project.tasks.count()},
        )
        return redirect("projects:template_list")

    context = {
        "project": project,
        "suggested_name": f"Template: {project.name}",
    }

    return render(request, "projects/project_save_as_template.html", context)


# =============================================================================
# Task Management Views
# =============================================================================


@block_source_user
@login_required
def task_create(request, project_pk):
    """Add a new task to a project"""
    user = request.user
    project = get_object_or_404(QIProject, pk=project_pk, is_template=False)

    # Check permission
    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to add tasks to this project."))
        return redirect("projects:project_detail", pk=project.pk)

    if request.method == "POST":
        form = QIProjectTaskForm(request.POST, project=project)
        if form.is_valid():
            task = form.save(commit=False)
            task.project = project
            task.save()
            messages.success(request, _("Task added successfully."))
            return redirect("projects:project_detail", pk=project.pk)
    else:
        form = QIProjectTaskForm(project=project)

    context = {
        "form": form,
        "project": project,
        "is_create": True,
    }

    return render(request, "projects/task_form.html", context)


@block_source_user
@login_required
def task_edit(request, project_pk, task_pk):
    """Edit an existing task"""
    user = request.user
    project = get_object_or_404(QIProject, pk=project_pk, is_template=False)
    task = get_object_or_404(QIProjectTask, pk=task_pk, project=project)

    # Check permission
    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to edit tasks in this project."))
        return redirect("projects:project_detail", pk=project.pk)

    if request.method == "POST":
        form = QIProjectTaskForm(request.POST, instance=task, project=project)
        if form.is_valid():
            task = form.save()
            # If status changed to completed, set completed_date
            if task.status == "completed" and not task.completed_date:
                from django.utils import timezone

                task.completed_date = timezone.now().date()
                task.save()
            messages.success(request, _("Task updated successfully."))
            return redirect("projects:project_detail", pk=project.pk)
    else:
        form = QIProjectTaskForm(instance=task, project=project)

    context = {
        "form": form,
        "project": project,
        "task": task,
        "is_create": False,
    }

    return render(request, "projects/task_form.html", context)


@block_source_user
@login_required
def task_delete(request, project_pk, task_pk):
    """Delete a task"""
    user = request.user
    project = get_object_or_404(QIProject, pk=project_pk, is_template=False)
    task = get_object_or_404(QIProjectTask, pk=task_pk, project=project)

    # Check permission
    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to delete tasks in this project."))
        return redirect("projects:project_detail", pk=project.pk)

    if request.method == "POST":
        task.delete()
        messages.success(request, _("Task deleted successfully."))
        return redirect("projects:project_detail", pk=project.pk)

    context = {
        "project": project,
        "task": task,
    }

    return render(request, "projects/task_delete_confirm.html", context)


@block_source_user
@login_required
def task_toggle_status(request, project_pk, task_pk):
    """Quick toggle task status between pending and completed"""
    user = request.user
    project = get_object_or_404(QIProject, pk=project_pk, is_template=False)
    task = get_object_or_404(QIProjectTask, pk=task_pk, project=project)

    # Check permission
    if not user.is_px_admin() and user.hospital and project.hospital != user.hospital:
        messages.error(request, _("You don't have permission to update tasks in this project."))
        return redirect("projects:project_detail", pk=project.pk)

    from django.utils import timezone

    if task.status == "completed":
        task.status = "pending"
        task.completed_date = None
    else:
        task.status = "completed"
        task.completed_date = timezone.now().date()

    task.save()
    messages.success(request, _("Task status updated."))
    return redirect("projects:project_detail", pk=project.pk)


# =============================================================================
# Template Management Views
# =============================================================================


@block_source_user
@login_required
def template_list(request):
    """List QI Project templates"""
    user = request.user

    # Only admins can manage templates
    if not (user.is_px_admin() or user.is_hospital_admin):
        messages.error(request, _("You don't have permission to view templates."))
        return redirect("projects:project_list")

    queryset = QIProject.objects.filter(is_template=True).select_related("hospital", "department")

    # Apply RBAC filters
    if not user.is_px_admin():
        from django.db.models import Q

        queryset = queryset.filter(Q(hospital=user.hospital) | Q(hospital__isnull=True))

    # Search
    search_query = request.GET.get("search")
    if search_query:
        queryset = queryset.filter(
            Q(name__icontains=search_query)
            | Q(description__icontains=search_query)
            | Q(name_ar__icontains=search_query)
        )

    queryset = queryset.order_by("name")

    context = {
        "templates": queryset,
        "can_create": user.is_px_admin() or user.is_hospital_admin,
        "can_edit": user.is_px_admin() or user.is_hospital_admin,
    }

    return render(request, "projects/template_list.html", context)


@block_source_user
@login_required
def template_detail(request, pk):
    """View template details with tasks"""
    user = request.user

    # Only admins can view templates
    if not (user.is_px_admin() or user.is_hospital_admin):
        messages.error(request, _("You don't have permission to view templates."))
        return redirect("projects:project_list")

    template = get_object_or_404(
        QIProject.objects.filter(is_template=True).select_related("hospital", "department"), pk=pk
    )

    # Check permission for hospital-specific templates
    if not user.is_px_admin():
        from django.db.models import Q

        if template.hospital and template.hospital != user.hospital:
            messages.error(request, _("You don't have permission to view this template."))
            return redirect("projects:template_list")

    # Get tasks
    tasks = template.tasks.all().order_by("order", "created_at")

    context = {
        "template": template,
        "tasks": tasks,
    }

    return render(request, "projects/template_detail.html", context)


@block_source_user
@login_required
def template_create(request):
    """Create a new project template"""
    user = request.user

    # Only admins can create templates
    if not (user.is_px_admin() or user.is_hospital_admin):
        messages.error(request, _("You don't have permission to create templates."))
        return redirect("projects:project_list")

    if request.method == "POST":
        form = QIProjectTemplateForm(request.POST, request=request)
        if form.is_valid():
            template = form.save(commit=False)
            template.is_template = True
            template.created_by = user
            template.save()
            
            # Save task templates formset
            formset = TaskTemplateFormSet(request.POST, instance=template, prefix='tasktemplate_set')
            if formset.is_valid():
                formset.save()
            
            messages.success(request, _("Project template created successfully."))
            return redirect("projects:template_list")
        else:
            # Form is invalid, show formset with errors
            formset = TaskTemplateFormSet(request.POST, prefix='tasktemplate_set')
    else:
        form = QIProjectTemplateForm(request=request)
        formset = TaskTemplateFormSet(prefix='tasktemplate_set')

    context = {
        "form": form,
        "formset": formset,
        "is_create": True,
    }

    return render(request, "projects/template_form.html", context)


@block_source_user
@login_required
def template_edit(request, pk):
    """Edit an existing project template"""
    user = request.user
    template = get_object_or_404(QIProject, pk=pk, is_template=True)

    # Check permission
    if not user.is_px_admin():
        if template.hospital and template.hospital != user.hospital:
            messages.error(request, _("You don't have permission to edit this template."))
            return redirect("projects:template_list")

    if request.method == "POST":
        form = QIProjectTemplateForm(request.POST, instance=template, request=request)
        formset = TaskTemplateFormSet(request.POST, instance=template, prefix='tasktemplate_set')
        if form.is_valid() and formset.is_valid():
            form.save()
            formset.save()
            messages.success(request, _("Project template updated successfully."))
            return redirect("projects:template_list")
    else:
        form = QIProjectTemplateForm(instance=template, request=request)
        formset = TaskTemplateFormSet(instance=template, prefix='tasktemplate_set')

    context = {
        "form": form,
        "formset": formset,
        "template": template,
        "is_create": False,
    }

    return render(request, "projects/template_form.html", context)


@block_source_user
@login_required
def template_delete(request, pk):
    """Delete a project template"""
    user = request.user
    template = get_object_or_404(QIProject, pk=pk, is_template=True)

    # Check permission
    if not user.is_px_admin():
        if template.hospital and template.hospital != user.hospital:
            messages.error(request, _("You don't have permission to delete this template."))
            return redirect("projects:template_list")

    if request.method == "POST":
        template_name = template.name
        template.delete()
        messages.success(request, _('Template "%(name)s" deleted successfully.') % {"name": template_name})
        return redirect("projects:template_list")

    context = {
        "template": template,
    }

    return render(request, "projects/template_delete_confirm.html", context)


# =============================================================================
# PX Action Conversion View
# =============================================================================


@block_source_user
@login_required
def convert_action_to_project(request, action_pk):
    """Convert a PX Action to a QI Project"""
    user = request.user

    # Check permission
    if not (user.is_px_admin() or user.is_hospital_admin or user.is_department_manager):
        messages.error(request, _("You don't have permission to create projects."))
        return redirect("px_action_center:action_detail", pk=action_pk)

    action = get_object_or_404(PXAction, pk=action_pk)

    # Check hospital access
    if not user.is_px_admin() and user.hospital and action.hospital != user.hospital:
        messages.error(request, _("You don't have permission to convert this action."))
        return redirect("px_action_center:action_detail", pk=action_pk)

    if request.method == "POST":
        form = ConvertToProjectForm(request.POST, request=request, action=action)
        if form.is_valid():
            # Create project from template or blank
            template = form.cleaned_data.get("template")

            if template:
                # Copy from template
                project = QIProject.objects.create(
                    name=form.cleaned_data["project_name"],
                    name_ar=template.name_ar,
                    description=template.description,
                    hospital=action.hospital,
                    department=template.department,
                    project_lead=form.cleaned_data["project_lead"],
                    target_completion_date=form.cleaned_data["target_completion_date"],
                    status="pending",
                    created_by=user,
                )
                # Copy tasks from template
                for template_task in template.tasks.all():
                    QIProjectTask.objects.create(
                        project=project,
                        title=template_task.title,
                        description=template_task.description,
                        order=template_task.order,
                        status="pending",
                    )
            else:
                # Create blank project
                project = QIProject.objects.create(
                    name=form.cleaned_data["project_name"],
                    description=action.description,
                    hospital=action.hospital,
                    project_lead=form.cleaned_data["project_lead"],
                    target_completion_date=form.cleaned_data["target_completion_date"],
                    status="pending",
                    created_by=user,
                )

            # Link to the action
            project.related_actions.add(action)

            messages.success(request, _("PX Action converted to QI Project successfully."))
            return redirect("projects:project_detail", pk=project.pk)
    else:
        initial_data = {
            "project_name": f"QI Project: {action.title}",
        }
        form = ConvertToProjectForm(request=request, action=action, initial=initial_data)

    context = {
        "form": form,
        "action": action,
    }

    return render(request, "projects/convert_action.html", context)