import { useState, useEffect, useCallback } from 'react';
import { Link, useParams } from 'react-router-dom';
import { adminData } from '@/lib/adminApi';
import { auditedAdminData } from '@/hooks/useAuditedAdminData';
import { useEntityForm } from '@/hooks/useEntityForm';
import { Button } from '@/components/ui/button';
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
import { Badge } from '@/components/ui/badge';
import { Skeleton } from '@/components/ui/skeleton';
import { PaginationControls } from '@/components/ui/pagination';
import { Plus, MessageCircle, Pencil, Trash2, Sparkles, Crown, Eye, EyeOff, Tags, ChevronUp, ChevronDown, Clock, BellOff } from 'lucide-react';
import { toast } from 'sonner';
import { AiGeneratorDialog } from '@/components/ai/AiGeneratorDialog';
import { ExtractTopicsDialog } from '@/components/content/ExtractTopicsDialog';
import { PackFormDialog, type PackFormData } from '@/components/content/PackFormDialog';
import { IconPreview } from '@/components/ui/icon-picker';
import { ContentReviewControl } from '@/components/content/ContentReviewControl';
import type { ContentReviewStatus } from '@sauci/shared';

// =============================================================================
// Types
// =============================================================================

interface Category {
    id: string;
    name: string;
    icon?: string | null;
}

interface Topic {
    id: string;
    name: string;
}

interface QuestionPack {
    id: string;
    name: string;
    description: string | null;
    icon: string | null;
    is_premium: boolean;
    is_public: boolean;
    is_explicit: boolean;
    sort_order: number | null;
    category_id: string | null;
    created_at: string | null;
    scheduled_release_at?: string | null;  // Optional for backwards compatibility
    release_notified?: boolean;  // True if notifications have been sent or should be skipped
    content_status?: ContentReviewStatus | null;
    content_review_reason?: string | null;
    question_count?: number;
    topics?: Topic[];
}

// =============================================================================
// Component
// =============================================================================

export function PacksPage() {
    const { categoryId } = useParams<{ categoryId: string }>();

    // Data state
    const [category, setCategory] = useState<Category | null>(null);
    const [categories, setCategories] = useState<Category[]>([]);
    const [packs, setPacks] = useState<QuestionPack[]>([]);
    const [loading, setLoading] = useState(true);
    const [aiDialogOpen, setAiDialogOpen] = useState(false);
    const [extractTopicsDialogOpen, setExtractTopicsDialogOpen] = useState(false);
    const [extractTopicsPack, setExtractTopicsPack] = useState<QuestionPack | null>(null);
    const [allTopics, setAllTopics] = useState<Topic[]>([]);
    const [selectedTopicIds, setSelectedTopicIds] = useState<Set<string>>(new Set());
    const [page, setPage] = useState(1);
    const [pageSize, setPageSize] = useState(12);
    const [totalCount, setTotalCount] = useState(0);

    // Form state using the hook
    const form = useEntityForm<PackFormData, QuestionPack>(
        {
            name: '',
            description: '',
            icon: 'heart-outline',
            is_premium: false,
            is_public: false,
            is_explicit: false,
            category_id: categoryId ?? '',
            scheduled_release_at: null,
            skip_notification: false,
        },
        (pack) => ({
            name: pack.name,
            description: pack.description || '',
            icon: pack.icon || 'heart-outline',
            is_premium: pack.is_premium,
            is_public: pack.is_public,
            is_explicit: pack.is_explicit,
            category_id: pack.category_id || '',
            scheduled_release_at: pack.scheduled_release_at,
            skip_notification: false,  // Always start unchecked when editing
        })
    );

    // =============================================================================
    // Data Fetching
    // =============================================================================

    const fetchData = useCallback(async () => {
        setLoading(true);
        try {
            // Fetch category info
            if (categoryId) {
                const { data: cat } = await adminData
                    .from('categories')
                    .select('id, name, icon')
                    .eq('id', categoryId)
                    .single();
                setCategory(cat);
            }

            const { data: categoriesData } = await adminData
                .from('categories')
                .select('id, name')
                .order('name');
            setCategories(categoriesData || []);

            const from = (page - 1) * pageSize;
            const to = from + pageSize - 1;

            // Fetch packs
            let query = adminData
                .from('question_packs')
                .select('*', { count: 'exact' })
                .order('sort_order', { ascending: true })
                .range(from, to);

            if (categoryId) {
                query = query.eq('category_id', categoryId);
            }

            const { data: packData, error, count } = await query;
            if (error) throw error;

            setTotalCount(count || 0);

            // Fetch question counts
            const packIds = (packData || []).map(p => p.id);
            const questionCounts: Record<string, number> = {};

            if (packIds.length > 0) {
                const { data: questions } = await adminData
                    .from('questions')
                    .select('pack_id')
                    .in('pack_id', packIds);

                questions?.forEach(q => {
                    questionCounts[q.pack_id] = (questionCounts[q.pack_id] || 0) + 1;
                });
            }

            // Fetch all topics
            const { data: topicsData } = await adminData
                .from('topics')
                .select('id, name')
                .order('name');
            setAllTopics(topicsData || []);

            // Fetch pack_topics relationships
            let packTopicsData: any[] = [];
            if (packIds.length > 0) {
                const { data } = await adminData
                    .from('pack_topics')
                    .select('pack_id, topic_id, topics(id, name)')
                    .in('pack_id', packIds);
                packTopicsData = data || [];
            }

            const packTopicsMap: Record<string, Topic[]> = {};
            packTopicsData.forEach((pt: any) => {
                if (!packTopicsMap[pt.pack_id]) {
                    packTopicsMap[pt.pack_id] = [];
                }
                if (pt.topics) {
                    packTopicsMap[pt.pack_id].push(pt.topics);
                }
            });

            setPacks(
                (packData || []).map(p => ({
                    ...p,
                    question_count: questionCounts[p.id] || 0,
                    topics: packTopicsMap[p.id] || [],
                }))
            );
        } catch (error) {
            toast.error('Failed to load packs');
            console.error(error);
        } finally {
            setLoading(false);
        }
    }, [categoryId, page, pageSize]);

    useEffect(() => {
        fetchData();
    }, [fetchData]);

    useEffect(() => {
        const totalPages = Math.max(1, Math.ceil(totalCount / pageSize));
        if (page > totalPages) {
            setPage(totalPages);
        }
    }, [page, pageSize, totalCount]);

    // =============================================================================
    // Handlers
    // =============================================================================

    const openCreate = () => {
        form.openCreate();
        setSelectedTopicIds(new Set());
    };

    const openEdit = (pack: QuestionPack) => {
        form.openEdit(pack);
        setSelectedTopicIds(new Set(pack.topics?.map(t => t.id) || []));
    };

    const handleSave = async () => {
        if (!form.formData.name.trim()) {
            toast.error('Name is required');
            return;
        }

        form.setSaving(true);
        try {
            let packId: string;

            if (form.editingItem) {
                // Determine release_notified value
                // If skip_notification is checked, set release_notified=true to prevent notifications
                // Otherwise, reset to false when scheduling a new release
                const releaseNotifiedValue = form.formData.skip_notification
                    ? true
                    : (form.formData.scheduled_release_at ? false : undefined);

                const { error } = await auditedAdminData.update('question_packs', form.editingItem.id, {
                    name: form.formData.name,
                    description: form.formData.description || null,
                    icon: form.formData.icon || null,
                    is_premium: form.formData.is_premium,
                    is_public: form.formData.is_public,
                    is_explicit: form.formData.is_explicit,
                    category_id: form.formData.category_id || null,
                    // Only include scheduled_release_at if the field exists in form data (backwards compatible)
                    ...('scheduled_release_at' in form.formData && {
                        scheduled_release_at: form.formData.scheduled_release_at,
                        // Set release_notified based on skip_notification toggle
                        ...(releaseNotifiedValue !== undefined && { release_notified: releaseNotifiedValue }),
                    }),
                });
                if (error) throw error;
                packId = form.editingItem.id;
            } else {
                const { data, error } = await adminData
                    .from('question_packs')
                    .insert({
                        name: form.formData.name,
                        description: form.formData.description || null,
                        icon: form.formData.icon || null,
                        is_premium: form.formData.is_premium,
                        is_public: form.formData.is_public,
                        is_explicit: form.formData.is_explicit,
                        category_id: form.formData.category_id || null,
                        sort_order: totalCount,
                        // Only include scheduled_release_at if the field exists in form data (backwards compatible)
                        ...('scheduled_release_at' in form.formData && {
                            scheduled_release_at: form.formData.scheduled_release_at,
                            // If skip_notification is checked, set release_notified=true
                            ...(form.formData.skip_notification && { release_notified: true }),
                        }),
                    })
                    .select('id')
                    .single();
                if (error) throw error;
                packId = data.id;
            }

            // Update topics
            await adminData.from('pack_topics').delete().eq('pack_id', packId);

            if (selectedTopicIds.size > 0) {
                const { error: topicsError } = await adminData
                    .from('pack_topics')
                    .insert(
                        Array.from(selectedTopicIds).map(topicId => ({
                            pack_id: packId,
                            topic_id: topicId,
                        }))
                    );
                if (topicsError) throw topicsError;
            }

            toast.success(form.isEditing ? 'Pack updated' : 'Pack created');
            form.close();
            fetchData();
        } catch (error) {
            toast.error('Failed to save pack');
            console.error(error);
        } finally {
            form.setSaving(false);
        }
    };

    const handleDelete = async (pack: QuestionPack) => {
        if (!confirm(`Delete pack "${pack.name}"? This will delete all questions in this pack.`)) {
            return;
        }

        try {
            const { error } = await auditedAdminData.delete('question_packs', pack.id);
            if (error) throw error;
            toast.success('Pack deleted');
            fetchData();
        } catch (error) {
            toast.error('Failed to delete pack');
            console.error(error);
        }
    };

    const handleAiGenerated = (result: { name?: string; description?: string; icon?: string }) => {
        if (result.description) {
            form.openCreateWith({
                name: result.name || '',
                description: result.description,
                icon: result.icon || 'heart-outline',
                is_premium: false,
                is_public: false,
                is_explicit: false,
                category_id: categoryId ?? '',
                scheduled_release_at: null,
                skip_notification: false,
            });
            setAiDialogOpen(false);
            setSelectedTopicIds(new Set());
        }
    };

    const handleMove = async (pack: QuestionPack, direction: 'up' | 'down') => {
        const currentIndex = packs.findIndex(p => p.id === pack.id);
        const targetIndex = direction === 'up' ? currentIndex - 1 : currentIndex + 1;

        if (targetIndex < 0 || targetIndex >= packs.length) return;

        const targetPack = packs[targetIndex];

        try {
            const currentOrder = pack.sort_order ?? currentIndex;
            const targetOrder = targetPack.sort_order ?? targetIndex;

            const [currentUpdate, targetUpdate] = await Promise.all([
                auditedAdminData.update('question_packs', pack.id, { sort_order: targetOrder }),
                auditedAdminData.update('question_packs', targetPack.id, { sort_order: currentOrder }),
            ]);

            if (currentUpdate.error || targetUpdate.error) {
                throw currentUpdate.error ?? targetUpdate.error ?? new Error('Failed to update pack order');
            }

            // Optimistic update
            const newPacks = [...packs];
            newPacks[currentIndex] = { ...targetPack, sort_order: currentOrder };
            newPacks[targetIndex] = { ...pack, sort_order: targetOrder };
            setPacks(newPacks);
        } catch (error) {
            toast.error('Failed to reorder packs');
            console.error(error);
            fetchData();
        }
    };

    // =============================================================================
    // Render
    // =============================================================================

    if (loading) {
        return (
            <div className="space-y-6">
                <div className="flex items-center justify-between">
                    <Skeleton className="h-9 w-64" />
                    <Skeleton className="h-10 w-40" />
                </div>
                <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
                    {[1, 2, 3].map(i => (
                        <Skeleton key={i} className="h-48" />
                    ))}
                </div>
            </div>
        );
    }

    return (
        <div className="space-y-6">
            {/* Header */}
            <div className="flex items-center justify-between">
                <div>
                    <h1 className="text-3xl font-bold tracking-tight flex items-center gap-2">
                        {category && (
                            <>
                                <span className="text-3xl">
                                    <IconPreview value={category.icon} fallback="bookmark-outline" className="text-3xl" />
                                </span>
                                {category.name}:
                            </>
                        )}
                        Question Packs
                    </h1>
                    <p className="text-muted-foreground">
                        {category
                            ? `Manage packs in the ${category.name} category`
                            : 'Manage all question packs'}
                    </p>
                </div>
                <div className="flex gap-2">
                    <Button variant="outline" onClick={() => setAiDialogOpen(true)}>
                        <Sparkles className="mr-2 h-4 w-4" />
                        Ideas
                    </Button>
                    <Button onClick={openCreate}>
                        <Plus className="mr-2 h-4 w-4" />
                        Add Pack
                    </Button>
                </div>
            </div>

            {/* Pack Form Dialog */}
            <PackFormDialog
                open={form.dialogOpen}
                onOpenChange={form.setDialogOpen}
                formData={form.formData}
                onFormChange={form.setFormData}
                onSave={handleSave}
                saving={form.saving}
                isEditing={form.isEditing}
                categories={categories}
                allTopics={allTopics}
                selectedTopicIds={selectedTopicIds}
                onTopicsChange={setSelectedTopicIds}
            />

            {/* AI Generator Dialog */}
            <AiGeneratorDialog
                open={aiDialogOpen}
                onOpenChange={setAiDialogOpen}
                type="category-pack-ideas"
                context={{
                    categoryName: category?.name,
                    existingPacks: packs.map(p => p.name)
                }}
                onGenerated={handleAiGenerated}
            />

            {/* Extract Topics Dialog */}
            {extractTopicsPack && (
                <ExtractTopicsDialog
                    open={extractTopicsDialogOpen}
                    onOpenChange={setExtractTopicsDialogOpen}
                    pack={extractTopicsPack}
                    onUpdated={fetchData}
                />
            )}

            {/* Packs Grid */}
            {packs.length === 0 ? (
                <Card className="flex flex-col items-center justify-center py-12">
                    <MessageCircle className="h-12 w-12 text-muted-foreground mb-4" />
                    <h3 className="text-lg font-semibold">No packs yet</h3>
                    <p className="text-muted-foreground mb-4">
                        Create your first question pack to get started
                    </p>
                    <div className="flex gap-2">
                        <Button variant="outline" onClick={() => setAiDialogOpen(true)}>
                            <Sparkles className="mr-2 h-4 w-4" />
                            Ideas
                        </Button>
                        <Button onClick={openCreate}>
                            <Plus className="mr-2 h-4 w-4" />
                            Add Pack
                        </Button>
                    </div>
                </Card>
            ) : (
                <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
                    {packs.map((pack, index) => (
                        <Card key={pack.id} className="group hover:shadow-md transition-shadow">
                            <CardHeader className="pb-3">
                                <div className="flex items-start justify-between">
                                    <div className="flex items-center gap-2">
                                        <div className="flex flex-col opacity-0 group-hover:opacity-100 transition-opacity">
                                            <Button
                                                variant="ghost"
                                                size="icon"
                                                className="h-6 w-6"
                                                onClick={() => handleMove(pack, 'up')}
                                                disabled={index === 0}
                                            >
                                                <ChevronUp className="h-4 w-4" />
                                            </Button>
                                            <Button
                                                variant="ghost"
                                                size="icon"
                                                className="h-6 w-6"
                                                onClick={() => handleMove(pack, 'down')}
                                                disabled={index === packs.length - 1}
                                            >
                                                <ChevronDown className="h-4 w-4" />
                                            </Button>
                                        </div>
                                        <div className="text-4xl mb-2">
                                            <IconPreview value={pack.icon} fallback="heart-outline" className="text-4xl" />
                                        </div>
                                    </div>
                                    <div className="flex items-center gap-1">
                                        <ContentReviewControl
                                            table="question_packs"
                                            entityId={pack.id}
                                            entityLabel={`pack “${pack.name}”`}
                                            status={pack.content_status}
                                            reason={pack.content_review_reason}
                                            onChanged={fetchData}
                                            compact
                                        />
                                        {pack.is_explicit && (
                                            <Badge variant="destructive">
                                                NSFW
                                            </Badge>
                                        )}
                                        {pack.is_premium && (
                                            <Badge variant="default" className="bg-amber-500">
                                                <Crown className="h-3 w-3 mr-1" />
                                                Premium
                                            </Badge>
                                        )}
                                        {pack.is_public ? (
                                            <Badge variant="outline" className="border-green-500 text-green-400">
                                                <Eye className="h-3 w-3 mr-1" />
                                                Published
                                            </Badge>
                                        ) : pack.scheduled_release_at ? (
                                            <>
                                                <Badge variant="outline" className="border-blue-500 text-blue-400" title={`Releases: ${new Date(pack.scheduled_release_at).toLocaleString()}`}>
                                                    <Clock className="h-3 w-3 mr-1" />
                                                    Scheduled
                                                </Badge>
                                                {pack.release_notified && (
                                                    <Badge variant="outline" className="border-gray-500 text-gray-400" title="Notifications skipped">
                                                        <BellOff className="h-3 w-3" />
                                                    </Badge>
                                                )}
                                            </>
                                        ) : (
                                            <Badge variant="secondary">
                                                <EyeOff className="h-3 w-3 mr-1" />
                                                Draft
                                            </Badge>
                                        )}
                                    </div>
                                </div>
                                <div className="flex items-start justify-between">
                                    <CardTitle className="flex-1">{pack.name}</CardTitle>
                                    <div className="opacity-0 group-hover:opacity-100 transition-opacity flex gap-1">
                                        <Button
                                            variant="ghost"
                                            size="icon"
                                            onClick={() => {
                                                setExtractTopicsPack(pack);
                                                setExtractTopicsDialogOpen(true);
                                            }}
                                            title="Extract Topics"
                                        >
                                            <Tags className="h-4 w-4 text-blue-400" />
                                        </Button>
                                        <Button
                                            variant="ghost"
                                            size="icon"
                                            onClick={() => openEdit(pack)}
                                        >
                                            <Pencil className="h-4 w-4" />
                                        </Button>
                                        <Button
                                            variant="ghost"
                                            size="icon"
                                            onClick={() => handleDelete(pack)}
                                        >
                                            <Trash2 className="h-4 w-4 text-destructive" />
                                        </Button>
                                    </div>
                                </div>
                                <CardDescription className="line-clamp-2">
                                    {pack.description || 'No description'}
                                </CardDescription>
                                {/* Topics */}
                                {pack.topics && pack.topics.length > 0 && (
                                    <div className="flex flex-wrap gap-1 mt-2">
                                        {pack.topics.map(topic => (
                                            <Badge key={topic.id} variant="outline" className="text-xs">
                                                {topic.name}
                                            </Badge>
                                        ))}
                                    </div>
                                )}
                            </CardHeader>
                            <CardContent>
                                <div className="flex items-center justify-between">
                                    <span className="text-sm text-muted-foreground">
                                        {pack.question_count} question{pack.question_count !== 1 ? 's' : ''}
                                    </span>
                                    <Link to={`/packs/${pack.id}/questions`}>
                                        <Button variant="outline" size="sm">
                                            Manage Questions
                                        </Button>
                                    </Link>
                                </div>
                            </CardContent>
                        </Card>
                    ))}
                </div>
            )}

            {packs.length > 0 && (
                <PaginationControls
                    page={page}
                    pageSize={pageSize}
                    totalCount={totalCount}
                    onPageChange={setPage}
                    onPageSizeChange={(size) => {
                        setPage(1);
                        setPageSize(size);
                    }}
                />
            )}
        </div>
    );
}