import { desc, eq, sql } from "drizzle-orm";
import { db as prodDb } from "../../db/index.ts";
import {
	categories,
	items,
	threadCandidates,
	threads,
} from "../../db/schema.ts";
import type { CreateCandidate, CreateThread } from "../../shared/types.ts";

type Db = typeof prodDb;

export function createThread(db: Db = prodDb, data: CreateThread) {
	return db
		.insert(threads)
		.values({ name: data.name, categoryId: data.categoryId })
		.returning()
		.get();
}

export function getAllThreads(db: Db = prodDb, includeResolved = false) {
	const query = db
		.select({
			id: threads.id,
			name: threads.name,
			status: threads.status,
			resolvedCandidateId: threads.resolvedCandidateId,
			categoryId: threads.categoryId,
			categoryName: categories.name,
			categoryIcon: categories.icon,
			createdAt: threads.createdAt,
			updatedAt: threads.updatedAt,
			candidateCount: sql<number>`(
        SELECT COUNT(*) FROM thread_candidates
        WHERE thread_candidates.thread_id = threads.id
      )`.as("candidate_count"),
			minPriceCents: sql<number | null>`(
        SELECT MIN(price_cents) FROM thread_candidates
        WHERE thread_candidates.thread_id = threads.id
      )`.as("min_price_cents"),
			maxPriceCents: sql<number | null>`(
        SELECT MAX(price_cents) FROM thread_candidates
        WHERE thread_candidates.thread_id = threads.id
      )`.as("max_price_cents"),
		})
		.from(threads)
		.innerJoin(categories, eq(threads.categoryId, categories.id))
		.orderBy(desc(threads.createdAt));

	if (!includeResolved) {
		return query.where(eq(threads.status, "active")).all();
	}
	return query.all();
}

export function getThreadWithCandidates(db: Db = prodDb, threadId: number) {
	const thread = db
		.select()
		.from(threads)
		.where(eq(threads.id, threadId))
		.get();
	if (!thread) return null;

	const candidateList = db
		.select({
			id: threadCandidates.id,
			threadId: threadCandidates.threadId,
			name: threadCandidates.name,
			weightGrams: threadCandidates.weightGrams,
			priceCents: threadCandidates.priceCents,
			categoryId: threadCandidates.categoryId,
			notes: threadCandidates.notes,
			productUrl: threadCandidates.productUrl,
			imageFilename: threadCandidates.imageFilename,
			status: threadCandidates.status,
			createdAt: threadCandidates.createdAt,
			updatedAt: threadCandidates.updatedAt,
			categoryName: categories.name,
			categoryIcon: categories.icon,
		})
		.from(threadCandidates)
		.innerJoin(categories, eq(threadCandidates.categoryId, categories.id))
		.where(eq(threadCandidates.threadId, threadId))
		.all();

	return { ...thread, candidates: candidateList };
}

export function updateThread(
	db: Db = prodDb,
	threadId: number,
	data: Partial<{ name: string; categoryId: number }>,
) {
	const existing = db
		.select({ id: threads.id })
		.from(threads)
		.where(eq(threads.id, threadId))
		.get();
	if (!existing) return null;

	return db
		.update(threads)
		.set({ ...data, updatedAt: new Date() })
		.where(eq(threads.id, threadId))
		.returning()
		.get();
}

export function deleteThread(db: Db = prodDb, threadId: number) {
	const thread = db
		.select()
		.from(threads)
		.where(eq(threads.id, threadId))
		.get();
	if (!thread) return null;

	// Collect candidate image filenames for cleanup
	const candidatesWithImages = db
		.select({ imageFilename: threadCandidates.imageFilename })
		.from(threadCandidates)
		.where(eq(threadCandidates.threadId, threadId))
		.all()
		.filter((c) => c.imageFilename != null);

	db.delete(threads).where(eq(threads.id, threadId)).run();

	return {
		...thread,
		candidateImages: candidatesWithImages.map((c) => c.imageFilename!),
	};
}

export function createCandidate(
	db: Db = prodDb,
	threadId: number,
	data: Partial<CreateCandidate> & {
		name: string;
		categoryId: number;
		imageFilename?: string;
	},
) {
	return db
		.insert(threadCandidates)
		.values({
			threadId,
			name: data.name,
			weightGrams: data.weightGrams ?? null,
			priceCents: data.priceCents ?? null,
			categoryId: data.categoryId,
			notes: data.notes ?? null,
			productUrl: data.productUrl ?? null,
			imageFilename: data.imageFilename ?? null,
			status: data.status ?? "researching",
		})
		.returning()
		.get();
}

export function updateCandidate(
	db: Db = prodDb,
	candidateId: number,
	data: Partial<{
		name: string;
		weightGrams: number;
		priceCents: number;
		categoryId: number;
		notes: string;
		productUrl: string;
		imageFilename: string;
		status: "researching" | "ordered" | "arrived";
	}>,
) {
	const existing = db
		.select({ id: threadCandidates.id })
		.from(threadCandidates)
		.where(eq(threadCandidates.id, candidateId))
		.get();
	if (!existing) return null;

	return db
		.update(threadCandidates)
		.set({ ...data, updatedAt: new Date() })
		.where(eq(threadCandidates.id, candidateId))
		.returning()
		.get();
}

export function deleteCandidate(db: Db = prodDb, candidateId: number) {
	const candidate = db
		.select()
		.from(threadCandidates)
		.where(eq(threadCandidates.id, candidateId))
		.get();
	if (!candidate) return null;

	db.delete(threadCandidates).where(eq(threadCandidates.id, candidateId)).run();
	return candidate;
}

export function resolveThread(
	db: Db = prodDb,
	threadId: number,
	candidateId: number,
): { success: boolean; item?: any; error?: string } {
	return db.transaction((tx) => {
		// 1. Check thread is active
		const thread = tx
			.select()
			.from(threads)
			.where(eq(threads.id, threadId))
			.get();
		if (!thread || thread.status !== "active") {
			return { success: false, error: "Thread not active" };
		}

		// 2. Get the candidate data
		const candidate = tx
			.select()
			.from(threadCandidates)
			.where(eq(threadCandidates.id, candidateId))
			.get();
		if (!candidate) {
			return { success: false, error: "Candidate not found" };
		}
		if (candidate.threadId !== threadId) {
			return { success: false, error: "Candidate not in thread" };
		}

		// 3. Verify categoryId still exists, fallback to Uncategorized (id=1)
		const category = tx
			.select({ id: categories.id })
			.from(categories)
			.where(eq(categories.id, candidate.categoryId))
			.get();
		const safeCategoryId = category ? candidate.categoryId : 1;

		// 4. Create collection item from candidate data
		const newItem = tx
			.insert(items)
			.values({
				name: candidate.name,
				weightGrams: candidate.weightGrams,
				priceCents: candidate.priceCents,
				categoryId: safeCategoryId,
				notes: candidate.notes,
				productUrl: candidate.productUrl,
				imageFilename: candidate.imageFilename,
			})
			.returning()
			.get();

		// 5. Archive the thread
		tx.update(threads)
			.set({
				status: "resolved",
				resolvedCandidateId: candidateId,
				updatedAt: new Date(),
			})
			.where(eq(threads.id, threadId))
			.run();

		return { success: true, item: newItem };
	});
}