"use client";

import { useEffect, useState } from "react";
import { useSession } from "next-auth/react";
import { notFound } from "next/navigation";
import { FileText, Loader2, Plus, Download, Edit2, Eye, Save } from "lucide-react";
import {
    EntityView,
    EntityViewHeader,
    EntityViewSection,
    EmptyState,
} from "~/components/ui/entity-view";
import { useBreadcrumbsEffect } from "~/components/ui/breadcrumb-provider";
import { Button } from "~/components/ui/button";
import { Badge } from "~/components/ui/badge";
import { api } from "~/trpc/react";
import { toast } from "sonner";
import { PageHeader } from "~/components/ui/page-header";
import { useEditor, EditorContent } from '@tiptap/react';
import StarterKit from '@tiptap/starter-kit';
import { Markdown } from 'tiptap-markdown';
import { Table } from '@tiptap/extension-table';
import { TableRow } from '@tiptap/extension-table-row';
import { TableCell } from '@tiptap/extension-table-cell';
import { TableHeader } from '@tiptap/extension-table-header';
import { Bold, Italic, List, ListOrdered, Heading1, Heading2, Quote, Table as TableIcon } from "lucide-react";
import { downloadPdfFromHtml } from "~/lib/pdf-generator";

const Toolbar = ({ editor }: { editor: any }) => {
    if (!editor) {
        return null;
    }

    return (
        <div className="border border-input bg-transparent rounded-tr-md rounded-tl-md p-1 flex items-center gap-1 flex-wrap">
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().toggleBold().run()}
                disabled={!editor.can().chain().focus().toggleBold().run()}
                className={editor.isActive('bold') ? 'bg-muted' : ''}
            >
                <Bold className="h-4 w-4" />
            </Button>
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().toggleItalic().run()}
                disabled={!editor.can().chain().focus().toggleItalic().run()}
                className={editor.isActive('italic') ? 'bg-muted' : ''}
            >
                <Italic className="h-4 w-4" />
            </Button>
            <div className="w-[1px] h-6 bg-border mx-1" />
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().toggleHeading({ level: 1 }).run()}
                className={editor.isActive('heading', { level: 1 }) ? 'bg-muted' : ''}
            >
                <Heading1 className="h-4 w-4" />
            </Button>
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().toggleHeading({ level: 2 }).run()}
                className={editor.isActive('heading', { level: 2 }) ? 'bg-muted' : ''}
            >
                <Heading2 className="h-4 w-4" />
            </Button>
            <div className="w-[1px] h-6 bg-border mx-1" />
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().toggleBulletList().run()}
                className={editor.isActive('bulletList') ? 'bg-muted' : ''}
            >
                <List className="h-4 w-4" />
            </Button>
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().toggleOrderedList().run()}
                className={editor.isActive('orderedList') ? 'bg-muted' : ''}
            >
                <ListOrdered className="h-4 w-4" />
            </Button>
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().toggleBlockquote().run()}
                className={editor.isActive('blockquote') ? 'bg-muted' : ''}
            >
                <Quote className="h-4 w-4" />
            </Button>
            <div className="w-[1px] h-6 bg-border mx-1" />
            <Button
                variant="ghost"
                size="sm"
                onClick={() => editor.chain().focus().insertTable({ rows: 3, cols: 3, withHeaderRow: true }).run()}
            >
                <TableIcon className="h-4 w-4" />
            </Button>
        </div>
    );
};

interface StudyFormsPageProps {
    params: Promise<{
        id: string;
    }>;
}

export default function StudyFormsPage({ params }: StudyFormsPageProps) {
    const { data: session } = useSession();
    const utils = api.useUtils();
    const [resolvedParams, setResolvedParams] = useState<{ id: string } | null>(null);
    const [editorTarget, setEditorTarget] = useState<string>("");

    useEffect(() => {
        const resolveParams = async () => {
            const resolved = await params;
            setResolvedParams(resolved);
        };
        void resolveParams();
    }, [params]);

    const { data: study } = api.studies.get.useQuery(
        { id: resolvedParams?.id ?? "" },
        { enabled: !!resolvedParams?.id },
    );

    const { data: activeConsentForm, refetch: refetchConsentForm } =
        api.studies.getActiveConsentForm.useQuery(
            { studyId: resolvedParams?.id ?? "" },
            { enabled: !!resolvedParams?.id },
        );

    // Only sync once when form loads to avoid resetting user edits
    useEffect(() => {
        if (activeConsentForm && !editorTarget) {
            setEditorTarget(activeConsentForm.content);
        }
    }, [activeConsentForm, editorTarget]);

    const editor = useEditor({
        extensions: [
            StarterKit,
            Table.configure({
                resizable: true,
            }),
            TableRow,
            TableHeader,
            TableCell,
            Markdown.configure({
                transformPastedText: true,
            }),
        ],
        content: editorTarget || '',
        immediatelyRender: false,
        onUpdate: ({ editor }) => {
            // @ts-ignore
            setEditorTarget(editor.storage.markdown.getMarkdown());
        },
    });

    // Sync Tiptap when editorTarget is set (e.g., from DB) but make sure not to overwrite active edits
    useEffect(() => {
        if (editor && editorTarget && editor.isEmpty) {
            editor.commands.setContent(editorTarget);
        }
    }, [editorTarget, editor]);

    const generateConsentMutation = api.studies.generateConsentForm.useMutation({
        onSuccess: (data) => {
            toast.success("Default Consent Form Generated!");
            setEditorTarget(data.content);
            editor?.commands.setContent(data.content);
            void refetchConsentForm();
            void utils.studies.getActivity.invalidate({ studyId: resolvedParams?.id ?? "" });
        },
        onError: (error) => {
            toast.error("Error generating consent form", { description: error.message });
        },
    });

    const updateConsentMutation = api.studies.updateConsentForm.useMutation({
        onSuccess: () => {
            toast.success("Consent Form Saved Successfully!");
            void refetchConsentForm();
            void utils.studies.getActivity.invalidate({ studyId: resolvedParams?.id ?? "" });
        },
        onError: (error) => {
            toast.error("Error saving consent form", { description: error.message });
        },
    });

    const handleDownloadConsent = async () => {
        if (!activeConsentForm || !study || !editor) return;

        try {
            toast.loading("Generating Document...", { id: "pdf-gen" });
            await downloadPdfFromHtml(editor.getHTML(), {
                filename: `Consent_Form_${study.name.replace(/\s+/g, "_")}_v${activeConsentForm.version}.pdf`
            });
            toast.success("Document Downloaded Successfully!", { id: "pdf-gen" });
        } catch (error) {
            toast.error("Error generating PDF", { id: "pdf-gen" });
            console.error(error);
        }
    };

    useBreadcrumbsEffect([
        { label: "Dashboard", href: "/dashboard" },
        { label: "Studies", href: "/studies" },
        { label: study?.name ?? "Study", href: `/studies/${resolvedParams?.id}` },
        { label: "Forms" },
    ]);

    if (!session?.user) {
        return notFound();
    }

    if (!study) return <div>Loading...</div>;

    return (
        <EntityView>
            <PageHeader
                title="Study Forms"
                description="Manage consent forms and future questionnaires for this study"
                icon={FileText}
            />

            <div className="grid grid-cols-1 gap-8">
                <EntityViewSection
                    title="Consent Document"
                    icon="FileText"
                    description="Design and manage the consent form that participants must sign before participating in your trials."
                    actions={
                        <div className="flex gap-2">
                            <Button
                                variant="outline"
                                size="sm"
                                onClick={() => generateConsentMutation.mutate({ studyId: study.id })}
                                disabled={generateConsentMutation.isPending || updateConsentMutation.isPending}
                            >
                                {generateConsentMutation.isPending ? (
                                    <Loader2 className="mr-2 h-4 w-4 animate-spin" />
                                ) : (
                                    <Plus className="mr-2 h-4 w-4" />
                                )}
                                Generate Default Template
                            </Button>
                            {activeConsentForm && (
                                <Button
                                    size="sm"
                                    onClick={() => updateConsentMutation.mutate({ studyId: study.id, content: editorTarget })}
                                    disabled={updateConsentMutation.isPending || editorTarget === activeConsentForm.content}
                                >
                                    {updateConsentMutation.isPending ? (
                                        <Loader2 className="mr-2 h-4 w-4 animate-spin" />
                                    ) : (
                                        <Save className="mr-2 h-4 w-4" />
                                    )}
                                    Save Changes
                                </Button>
                            )}
                        </div>
                    }
                >
                    {activeConsentForm ? (
                        <div className="space-y-4">
                            <div className="flex items-center justify-between">
                                <div className="space-y-1">
                                    <p className="text-sm font-medium leading-none">
                                        {activeConsentForm.title}
                                    </p>
                                    <p className="text-sm text-muted-foreground">
                                        v{activeConsentForm.version} • Status: Active
                                    </p>
                                </div>
                                <div className="flex items-center gap-3">
                                    <Button
                                        size="sm"
                                        variant="ghost"
                                        onClick={handleDownloadConsent}
                                    >
                                        <Download className="mr-2 h-4 w-4" />
                                        Download PDF
                                    </Button>
                                    <Badge variant="outline" className="bg-green-50 text-green-700 hover:bg-green-50">Active</Badge>
                                </div>
                            </div>

                            <div className="w-full flex justify-center bg-muted/30 p-8 rounded-md border border-border overflow-hidden">
                                <div className="max-w-4xl w-full bg-white dark:bg-card shadow-xl ring-1 ring-border rounded-sm flex flex-col">
                                    <div className="border-b border-border bg-muted/50 dark:bg-muted/10">
                                        <Toolbar editor={editor} />
                                    </div>
                                    <div className="min-h-[850px] px-16 py-20 text-sm editor-container bg-white dark:bg-card">
                                        <EditorContent editor={editor} className="prose prose-sm dark:prose-invert max-w-none h-full outline-none focus:outline-none focus-visible:outline-none" />
                                    </div>
                                </div>
                            </div>
                        </div>
                    ) : (
                        <EmptyState
                            icon="FileText"
                            title="No Consent Form"
                            description="Generate a boilerplate consent form for this study to download and collect signatures."
                        />
                    )}
                </EntityViewSection>
            </div>
        </EntityView>
    );
}