import {
  convertToModelMessages,
  stepCountIs,
  streamText,
  tool,
  type UIMessage,
} from "ai";
import { anthropic } from "@ai-sdk/anthropic";
import { z } from "zod";
import {
  reactEditorTools,
  getEditorContext,
} from "@reacteditor/plugin-ai/server";
import { shopifyFetch } from "@/editor/services/shopify/client";
import {
  GET_PRODUCTS_QUERY,
  GET_PRODUCT_QUERY,
} from "@/editor/graphql/products";
import {
  GET_COLLECTIONS_QUERY,
  GET_COLLECTION_PRODUCTS_QUERY,
} from "@/editor/graphql/collections";

type Body = {
  messages: UIMessage[];
  editorContext?: Parameters<typeof getEditorContext>[0];
  route?: string;
};

export async function POST(req: Request) {
  const { messages, editorContext } = (await req.json()) as Body;

  const generateImage = tool({
    description: "Generate an image from a prompt and return its URL.",
    inputSchema: z.object({
      prompt: z.string(),
      width: z.number().int().positive().optional(),
      height: z.number().int().positive().optional(),
    }),
    execute: async ({ width = 768, height = 768 }) => ({
      url: `https://picsum.photos/${width}/${height}?random=${Math.floor(
        Math.random() * 1_000_000,
      )}`,
    }),
  });

  const credentials = {
    domain:
      process.env.VITE_SHOPIFY_DOMAIN ??
      process.env.SHOPIFY_DOMAIN ??
      "mock.shop",
    token:
      process.env.VITE_SHOPIFY_STOREFRONT_ACCESS_TOKEN ??
      process.env.SHOPIFY_STOREFRONT_ACCESS_TOKEN ??
      "",
  };

  const searchProducts = tool({
    description:
      "Search the Shopify store for products. Returns up to `limit` products matching `query`.",
    inputSchema: z.object({
      query: z.string().optional(),
      limit: z.number().int().min(1).max(20).optional(),
    }),
    execute: async ({ query, limit = 8 }) => {
      try {
        const res = await shopifyFetch<any>({
          query: GET_PRODUCTS_QUERY,
          variables: {
            first: limit,
            query: query ?? null,
            sortKey: query ? "RELEVANCE" : "BEST_SELLING",
            reverse: false,
          },
          credentials,
        });
        const products = (res.data?.products?.edges ?? []).map((e: any) => {
          const n = e.node;
          return {
            id: n.id,
            handle: n.handle,
            title: n.title,
            description: n.description,
            featuredImage: n.images?.edges?.[0]?.node ?? null,
            priceRange: n.priceRange,
          };
        });
        return { ok: true, products };
      } catch (err) {
        return {
          ok: false,
          error: err instanceof Error ? err.message : "fetch failed",
        };
      }
    },
  });

  const getProductByHandle = tool({
    description: "Fetch a single product by its handle.",
    inputSchema: z.object({ handle: z.string() }),
    execute: async ({ handle }) => {
      try {
        const res = await shopifyFetch<any>({
          query: GET_PRODUCT_QUERY,
          variables: { handle },
          credentials,
        });
        const p = res.data?.product ?? null;
        if (!p) return { ok: false, error: "not_found" };
        return {
          ok: true,
          product: {
            id: p.id,
            handle: p.handle,
            title: p.title,
            description: p.description,
            featuredImage: p.images?.edges?.[0]?.node ?? null,
            priceRange: p.priceRange,
          },
        };
      } catch (err) {
        return {
          ok: false,
          error: err instanceof Error ? err.message : "fetch failed",
        };
      }
    },
  });

  const searchCollections = tool({
    description: "List up to `limit` collections from the Shopify store.",
    inputSchema: z.object({
      limit: z.number().int().min(1).max(20).optional(),
    }),
    execute: async ({ limit = 8 }) => {
      try {
        const res = await shopifyFetch<any>({
          query: GET_COLLECTIONS_QUERY,
          variables: { first: limit },
          credentials,
        });
        const collections = (res.data?.collections?.edges ?? []).map(
          (e: any) => {
            const n = e.node;
            return {
              id: n.id,
              handle: n.handle,
              title: n.title,
              description: n.description,
              image: n.image ?? null,
            };
          },
        );
        return { ok: true, collections };
      } catch (err) {
        return {
          ok: false,
          error: err instanceof Error ? err.message : "fetch failed",
        };
      }
    },
  });

  const getCollectionByHandle = tool({
    description:
      "Fetch a single collection by its handle, including a small page of its products.",
    inputSchema: z.object({
      handle: z.string(),
      limit: z.number().int().min(1).max(20).optional(),
    }),
    execute: async ({ handle, limit = 8 }) => {
      try {
        const res = await shopifyFetch<any>({
          query: GET_COLLECTION_PRODUCTS_QUERY,
          variables: {
            handle,
            first: limit,
            sortKey: "BEST_SELLING",
            reverse: false,
          },
          credentials,
        });
        const c = res.data?.collection ?? null;
        if (!c) return { ok: false, error: "not_found" };
        return {
          ok: true,
          collection: {
            id: c.id,
            handle: c.handle,
            title: c.title,
            description: c.description,
            image: c.image ?? null,
            products: (c.products?.edges ?? []).map((e: any) => ({
              id: e.node.id,
              handle: e.node.handle,
              title: e.node.title,
              featuredImage: e.node.images?.edges?.[0]?.node ?? null,
              priceRange: e.node.priceRange,
            })),
          },
        };
      } catch (err) {
        return {
          ok: false,
          error: err instanceof Error ? err.message : "fetch failed",
        };
      }
    },
  });

  const result = streamText({
    model: anthropic("claude-sonnet-4-5"),
    system: getEditorContext(editorContext),
    messages: await convertToModelMessages(messages),
    tools: {
      ...reactEditorTools,
      generateImage,
      searchProducts,
      getProductByHandle,
      searchCollections,
      getCollectionByHandle,
    },
    stopWhen: stepCountIs(50),
  });

  return result.toUIMessageStreamResponse();
}