import { NextRequest, NextResponse } from "next/server";
import PizZip from "pizzip";
import Docxtemplater from "docxtemplater";
import { readFile, writeFile } from "fs/promises";
import path from "path";
import db from "@/lib/db";
import { formatDate, formatCoordinates } from "@/lib/utils";

export async function POST(request) {
	try {
		const { templateId, projectId, customData } = await request.json();

		if (!templateId || !projectId) {
			return NextResponse.json(
				{ error: "templateId and projectId are required" },
				{ status: 400 }
			);
		}

		// Get template
		const template = db.prepare(`
			SELECT * FROM docx_templates WHERE template_id = ? AND is_active = 1
		`).get(templateId);

		if (!template) {
			return NextResponse.json(
				{ error: "Template not found" },
				{ status: 404 }
			);
		}

		// Get project data
		const project = db.prepare(`
			SELECT
				p.*,
				c.contract_number,
				c.customer_contract_number,
				c.customer,
				c.investor
			FROM projects p
			LEFT JOIN contracts c ON p.contract_id = c.contract_id
			WHERE p.project_id = ?
		`).get(projectId);

		if (!project) {
			return NextResponse.json(
				{ error: "Project not found" },
				{ status: 404 }
			);
		}

		// Get project contacts
		const contacts = db.prepare(`
			SELECT
				pc.*,
				ct.name,
				ct.phone,
				ct.email,
				ct.company,
				ct.contact_type
			FROM project_contacts pc
			JOIN contacts ct ON pc.contact_id = ct.contact_id
			WHERE pc.project_id = ?
			ORDER BY pc.is_primary DESC, ct.name
		`).all(projectId);

		// Load template file
		const templatePath = path.join(process.cwd(), "public", template.file_path);
		const templateContent = await readFile(templatePath);

		// Load the docx file as a binary
		const zip = new PizZip(templateContent);

		const doc = new Docxtemplater(zip, {
			paragraphLoop: true,
			linebreaks: true,
		});

		// Prepare data for template
		const templateData = {
			// Project basic info
			project_name: project.project_name || "",
			project_number: project.project_number || "",
			address: project.address || "",
			city: project.city || "",
			plot: project.plot || "",
			district: project.district || "",
			unit: project.unit || "",
			investment_number: project.investment_number || "",
			wp: project.wp || "",
			coordinates: project.coordinates || "",
			notes: project.notes || "",

			// Processed fields (extracted/transformed data)
			investment_number_short: project.investment_number ? project.investment_number.split('-').pop() : "",
			project_number_short: project.project_number ? project.project_number.split('-').pop() : "",
			project_name_upper: project.project_name ? project.project_name.toUpperCase() : "",
			project_name_lower: project.project_name ? project.project_name.toLowerCase() : "",
			city_upper: project.city ? project.city.toUpperCase() : "",
			customer_upper: project.customer ? project.customer.toUpperCase() : "",

			// Contract info
			contract_number: project.contract_number || "",
			customer_contract_number: project.customer_contract_number || "",
			customer: project.customer || "",
			investor: project.investor || "",

			// Dates
			finish_date: project.finish_date ? formatDate(project.finish_date) : "",
			completion_date: project.completion_date ? formatDate(project.completion_date) : "",
			today_date: formatDate(new Date()),

			// Project type and status
			project_type: project.project_type || "",
			project_status: project.project_status || "",

			// Financial
			wartosc_zlecenia: project.wartosc_zlecenia ? project.wartosc_zlecenia.toString() : "",

			// Contacts
			contacts: contacts.map(contact => ({
				name: contact.name || "",
				phone: contact.phone || "",
				email: contact.email || "",
				company: contact.company || "",
				contact_type: contact.contact_type || "",
				is_primary: contact.is_primary ? "Tak" : "Nie"
			})),

			// Primary contact
			primary_contact: contacts.find(c => c.is_primary)?.name || "",
			primary_contact_phone: contacts.find(c => c.is_primary)?.phone || "",
			primary_contact_email: contacts.find(c => c.is_primary)?.email || "",

			// Duplicate fields for repeated use (common fields that users might want to repeat)
			project_name_1: project.project_name || "",
			project_name_2: project.project_name || "",
			project_name_3: project.project_name || "",
			project_number_1: project.project_number || "",
			project_number_2: project.project_number || "",
			customer_1: project.customer || "",
			customer_2: project.customer || "",
			address_1: project.address || "",
			address_2: project.address || "",
			city_1: project.city || "",
			city_2: project.city || "",
			wartosc_zlecenia_1: project.wartosc_zlecenia ? project.wartosc_zlecenia.toString() : "",
			wartosc_zlecenia_2: project.wartosc_zlecenia ? project.wartosc_zlecenia.toString() : "",
		};

		// Merge custom data (custom data takes precedence over project data)
		if (customData && typeof customData === 'object') {
			Object.assign(templateData, customData);
		}

		// Set the template variables
		doc.setData(templateData);

		try {
			// Render the document
			doc.render();
		} catch (error) {
			console.error("Template rendering error:", error);

			// Check if it's a duplicate tags error
			if (error.name === 'TemplateError' && error.properties?.id === 'duplicate_open_tag') {
				return NextResponse.json(
					{
						error: "Template contains duplicate placeholders. Each placeholder (like {{project_name}}) can only be used once in the template. Please modify your DOCX template to use unique placeholders or remove duplicates.",
						details: `Duplicate tag found: ${error.properties?.xtag || 'unknown'}`
					},
					{ status: 400 }
				);
			}

			return NextResponse.json(
				{ error: "Failed to render template. Please check template syntax and ensure all placeholders are properly formatted." },
				{ status: 400 }
			);
		}

		// Get the generated document
		const buf = doc.getZip().generate({
			type: "nodebuffer",
			compression: "DEFLATE",
		});

		// Generate filename
		const timestamp = new Date().toISOString().slice(0, 19).replace(/:/g, "-");
		const sanitizedTemplateName = template.template_name.replace(/[^a-zA-Z0-9]/g, "_");
		const sanitizedProjectName = project.project_name.replace(/[^a-zA-Z0-9]/g, "_");
		const filename = `${sanitizedTemplateName}_${sanitizedProjectName}_${timestamp}.docx`;

		// Return the file as a downloadable response
		return new NextResponse(buf, {
			headers: {
				"Content-Type": "application/vnd.openxmlformats-officedocument.wordprocessingml.document",
				"Content-Disposition": `attachment; filename="${filename}"`,
			},
		});

	} catch (error) {
		console.error("Template generation error:", error);
		return NextResponse.json(
			{ error: "Failed to generate document" },
			{ status: 500 }
		);
	}
}