import { query, mutation, internalMutation } from "./_generated/server";
import { paginationOptsValidator } from "convex/server";
import { v } from "convex/values";
import type { Id } from "./_generated/dataModel";
import * as Users from "./model/users";
import { getOrderWithItems, validateCartItems, canCustomerCancel } from "./model/orders";
import * as CartsModel from "./model/carts";

export const listMine = query({
  args: {
    paginationOpts: paginationOptsValidator,
    statusFilter: v.optional(v.array(v.string())),
  },
  handler: async (ctx, args) => {
    const user = await Users.getCurrentUserOrThrow(ctx);
    const base = ctx.db
      .query("orders")
      .withIndex("by_user", (q) => q.eq("userId", user._id))
      .order("desc");

    if (args.statusFilter && args.statusFilter.length > 0) {
      const [first, ...rest] = args.statusFilter;
      return base
        .filter((q) => {
          const firstExpr = q.eq(q.field("status"), first as any);
          return rest.reduce(
            (acc: any, s) => q.or(acc, q.eq(q.field("status"), s as any)),
            firstExpr,
          );
        })
        .paginate(args.paginationOpts);
    }

    return base.paginate(args.paginationOpts);
  },
});

export const cancel = mutation({
  args: { id: v.id("orders") },
  handler: async (ctx, { id }) => {
    const user = await Users.getCurrentUserOrThrow(ctx);

    const order = await ctx.db.get(id);
    if (!order) throw new Error("Order not found");
    if (order.userId !== user._id)
      throw new Error("Unauthorized: order does not belong to you");

    const { allowed, reason } = canCustomerCancel(order);
    if (!allowed) throw new Error(reason);

    await ctx.db.patch(id, { status: "cancelled", updatedAt: Date.now() });

    // Restore stock for each line item
    const items = await ctx.db
      .query("orderItems")
      .withIndex("by_order", (q) => q.eq("orderId", id))
      .collect();

    for (const item of items) {
      const variant = await ctx.db.get(item.variantId);
      if (variant) {
        await ctx.db.patch(item.variantId, {
          stockQuantity: variant.stockQuantity + item.quantity,
        });
      }
    }

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

export const getById = query({
  args: { id: v.id("orders") },
  handler: async (ctx, { id }) => {
    const user = await Users.getCurrentUserOrThrow(ctx);
    const order = await getOrderWithItems(ctx, id);
    if (!order) throw new Error("Order not found");

    const isAdmin = user.role === "admin" || user.role === "super_admin";
    if (!isAdmin && order.userId !== user._id) {
      throw new Error("Unauthorized: order does not belong to you");
    }

    return order;
  },
});

export const listAll = query({
  args: {
    paginationOpts: paginationOptsValidator,
    status: v.optional(v.string()),
    paymentStatus: v.optional(v.string()),
  },
  handler: async (ctx, args) => {
    await Users.requireAdmin(ctx);

    let q;
    if (args.status) {
      q = ctx.db
        .query("orders")
        .withIndex("by_status", (idx) => idx.eq("status", args.status as any));
    } else if (args.paymentStatus) {
      q = ctx.db
        .query("orders")
        .withIndex("by_payment_status", (idx) =>
          idx.eq("paymentStatus", args.paymentStatus as any),
        );
    } else {
      q = ctx.db.query("orders");
    }

    return await q.order("desc").paginate(args.paginationOpts);
  },
});

export const create = mutation({
  args: {
    shippingAddressSnapshot: v.object({
      fullName: v.string(),
      firstName: v.string(),
      lastName: v.string(),
      addressLine1: v.string(),
      additionalInformation: v.optional(v.string()),
      city: v.string(),
      postalCode: v.string(),
      country: v.string(),
      phone: v.optional(v.string()),
    }),
    billingAddressSnapshot: v.object({
      firstName: v.string(),
      lastName: v.string(),
      addressLine1: v.string(),
      additionalInformation: v.optional(v.string()),
      city: v.string(),
      postalCode: v.string(),
      country: v.string(),
    }),
    items: v.array(
      v.object({
        variantId: v.id("productVariants"),
        productName: v.string(),
        variantName: v.string(),
        sku: v.string(),
        quantity: v.number(),
        unitPrice: v.number(),
        imageUrl: v.optional(v.string()),
      }),
    ),
    shippingCost: v.number(),
    tax: v.optional(v.number()),
    discount: v.number(),
    currency: v.optional(v.string()),
    notes: v.optional(v.string()),
    shippingMethod: v.optional(v.string()),
    shippingServiceCode: v.optional(v.string()),
    carrier: v.optional(v.string()),
    shippoShipmentId: v.optional(v.string()),
  },
  handler: async (ctx, args) => {
    const user = await Users.getCurrentUserOrThrow(ctx);

    const subtotal = args.items.reduce(
      (sum, item) => sum + item.unitPrice * item.quantity,
      0,
    );
    const tax = args.tax ?? 0;
    const total =
      subtotal + args.shippingCost - args.discount + tax;
    const now = Date.now();

    const orderNumber = `ORD-${Math.random().toString(36).substring(2, 7).toUpperCase()}`;

    const orderId = await ctx.db.insert("orders", {
      orderNumber,
      userId: user._id,
      email: user.email,
      status: "pending",
      paymentStatus: "pending",
      subtotal,
      tax,
      shipping: args.shippingCost,
      discount: args.discount,
      total,
      currency: args.currency ?? "USD",
      shippingAddressSnapshot: args.shippingAddressSnapshot,
      billingAddressSnapshot: args.billingAddressSnapshot,
      shippingMethod: args.shippingMethod ?? "",
      shippingServiceCode: args.shippingServiceCode ?? "",
      carrier: args.carrier ?? "",
      shippoShipmentId: args.shippoShipmentId ?? "",
      createdAt: now,
      updatedAt: now,
      notes: args.notes,
    });

    for (const item of args.items) {
      await ctx.db.insert("orderItems", {
        orderId,
        variantId: item.variantId,
        productName: item.productName,
        variantName: item.variantName,
        sku: item.sku,
        quantity: item.quantity,
        unitPrice: item.unitPrice,
        totalPrice: item.unitPrice * item.quantity,
        imageUrl: item.imageUrl,
      });
    }

    return orderId;
  },
});

const addressSnapshotValidator = {
  shippingAddressSnapshot: v.object({
    fullName: v.string(),
    firstName: v.string(),
    lastName: v.string(),
    addressLine1: v.string(),
    additionalInformation: v.optional(v.string()),
    city: v.string(),
    postalCode: v.string(),
    country: v.string(),
    phone: v.optional(v.string()),
  }),
  billingAddressSnapshot: v.object({
    firstName: v.string(),
    lastName: v.string(),
    addressLine1: v.string(),
    additionalInformation: v.optional(v.string()),
    city: v.string(),
    postalCode: v.string(),
    country: v.string(),
  }),
};

/**
 * @deprecated Use `checkout.validateCart` instead — returns enriched items
 * with weight/dimension data and richer issue types (price drift, inactive variants).
 *
 * No frontend code references this query. It can be removed once
 * `createFromCart` is refactored to use `validateAndEnrichCart` from
 * `model/checkout.ts` (planned for the Stripe webhook fulfillment phase).
 */
export const validateCart = query({
  args: { sessionId: v.optional(v.string()) },
  handler: async (ctx, args) => {
    const user = await Users.getCurrentUser(ctx);
    const userId = user?._id;
    if (!userId && !args.sessionId) {
      return { valid: true, outOfStock: [] };
    }
    const cart = await CartsModel.getCart(ctx, userId, args.sessionId);
    if (!cart || cart.items.length === 0) {
      return { valid: true, outOfStock: [] };
    }
    const outOfStock = await validateCartItems(ctx, cart.items);
    return { valid: outOfStock.length === 0, outOfStock };
  },
});

export const createFromCart = mutation({
  args: {
    ...addressSnapshotValidator,
    shippingCost: v.number(),
    tax: v.optional(v.number()),
    discount: v.number(),
    currency: v.optional(v.string()),
    notes: v.optional(v.string()),
  },
  handler: async (ctx, args) => {
    const user = await Users.getCurrentUserOrThrow(ctx);
    const cart = await CartsModel.getCart(ctx, user._id);
    if (!cart || cart.items.length === 0) {
      throw new Error("Cart is empty");
    }

    const outOfStock = await validateCartItems(ctx, cart.items);
    if (outOfStock.length > 0) {
      throw new Error("One or more items are out of stock");
    }

    const orderItems: {
      variantId: import("./_generated/dataModel").Id<"productVariants">;
      productName: string;
      variantName: string;
      sku: string;
      quantity: number;
      unitPrice: number;
      imageUrl?: string;
    }[] = [];

    for (const item of cart.items) {
      if (!item.variantId) continue;
      const variant = await ctx.db.get(item.variantId);
      const product = await ctx.db.get(item.productId);
      if (!variant || !product) continue;
      const images = await ctx.db
        .query("productImages")
        .withIndex("by_product", (q) => q.eq("productId", item.productId))
        .collect();
      images.sort((a, b) => a.position - b.position);
      orderItems.push({
        variantId: item.variantId,
        productName: product.name,
        variantName: variant.name,
        sku: variant.sku,
        quantity: item.quantity,
        unitPrice: item.price,
        imageUrl: images[0]?.url,
      });
    }

    if (orderItems.length === 0) {
      throw new Error("Cart has no valid items");
    }

    const subtotal = orderItems.reduce(
      (sum, item) => sum + item.unitPrice * item.quantity,
      0
    );
    const tax = args.tax ?? 0;
    const total = subtotal + args.shippingCost - args.discount + tax;
    const now = Date.now();
    const orderNumber = `ORD-${Math.random().toString(36).substring(2, 7).toUpperCase()}`;

    const orderId = await ctx.db.insert("orders", {
      orderNumber,
      userId: user._id,
      email: user.email,
      status: "pending",
      paymentStatus: "pending",
      subtotal,
      tax,
      shipping: args.shippingCost,
      discount: args.discount,
      total,
      currency: args.currency ?? "USD",
      shippingAddressSnapshot: args.shippingAddressSnapshot,
      billingAddressSnapshot: args.billingAddressSnapshot,
      shippoShipmentId: "",
      shippingMethod: "",
      shippingServiceCode: "",
      carrier: "",
      createdAt: now,
      updatedAt: now,
      notes: args.notes,
    });

    for (const item of orderItems) {
      await ctx.db.insert("orderItems", {
        orderId,
        variantId: item.variantId,
        productName: item.productName,
        variantName: item.variantName,
        sku: item.sku,
        quantity: item.quantity,
        unitPrice: item.unitPrice,
        totalPrice: item.unitPrice * item.quantity,
        imageUrl: item.imageUrl,
      });
    }

    await ctx.db.patch(cart._id, { items: [], updatedAt: now });
    return orderId;
  },
});

export const updateStatus = mutation({
  args: {
    id: v.id("orders"),
    status: v.union(
      v.literal("pending"),
      v.literal("confirmed"),
      v.literal("processing"),
      v.literal("shipped"),
      v.literal("delivered"),
      v.literal("cancelled"),
      v.literal("refunded"),
    ),
  },
  handler: async (ctx, { id, status }) => {
    await Users.requireAdmin(ctx);
    const order = await ctx.db.get(id);
    if (!order) throw new Error("Order not found");
    await ctx.db.patch(id, { status });
    return id;
  },
});

export const fulfillFromCheckout = internalMutation({
  args: {
    stripeCheckoutSessionId: v.string(),
    stripePaymentIntentId: v.union(v.string(), v.null()),
    convexUserId: v.string(),
    addressId: v.string(),
    shipmentObjectId: v.string(),
    shippingMethod: v.string(),
    shippingServiceCode: v.string(),
    carrier: v.string(),
    amountTotal: v.union(v.number(), v.null()),
    amountShipping: v.number(),
    currency: v.union(v.string(), v.null()),
  },
  handler: async (ctx, args) => {
    const existing = await ctx.db
      .query("orders")
      .withIndex("by_stripe_checkout_session_id", (q) =>
        q.eq("stripeCheckoutSessionId", args.stripeCheckoutSessionId),
      )
      .unique();
    if (existing) {
      console.log(
        "Order already exists for session:",
        args.stripeCheckoutSessionId,
      );
      return existing._id;
    }

    const userId = args.convexUserId as Id<"users">;
    const user = await ctx.db.get(userId);
    if (!user) throw new Error("User not found");

    const addressId = args.addressId as Id<"addresses">;
    const address = await ctx.db.get(addressId);
    if (!address) throw new Error("Address not found");

    const cart = await CartsModel.getCart(ctx, userId);
    if (!cart || cart.items.length === 0) throw new Error("Cart is empty");

    const orderItems: Array<{
      variantId: Id<"productVariants">;
      productName: string;
      variantName: string;
      sku: string;
      quantity: number;
      unitPrice: number;
      imageUrl: string | undefined;
    }> = [];

    for (const item of cart.items) {
      if (!item.variantId) continue;
      const variant = await ctx.db.get(item.variantId);
      const product = await ctx.db.get(item.productId);
      if (!variant || !product) continue;

      const images = await ctx.db
        .query("productImages")
        .withIndex("by_product", (q) => q.eq("productId", item.productId))
        .collect();
      images.sort((a, b) => a.position - b.position);

      orderItems.push({
        variantId: item.variantId,
        productName: product.name,
        variantName: variant.name,
        sku: variant.sku,
        quantity: item.quantity,
        unitPrice: variant.price,
        imageUrl: images[0]?.url,
      });
    }

    if (orderItems.length === 0) {
      throw new Error("Cart has no valid items");
    }

    const subtotal = orderItems.reduce(
      (sum, item) => sum + item.unitPrice * item.quantity,
      0,
    );
    const shipping = args.amountShipping;
    const total = args.amountTotal ?? subtotal + shipping;
    const now = Date.now();
    const orderNumber = `ORD-${Math.random().toString(36).substring(2, 7).toUpperCase()}`;

    const orderId = await ctx.db.insert("orders", {
      orderNumber,
      userId,
      email: user.email,
      status: "confirmed",
      paymentStatus: "paid",
      subtotal,
      tax: 0,
      shipping,
      discount: 0,
      total,
      currency: args.currency ?? "gbp",
      shippingAddressSnapshot: {
        fullName: address.fullName,
        firstName: address.firstName,
        lastName: address.lastName,
        addressLine1: address.addressLine1,
        additionalInformation: address.additionalInformation,
        city: address.city,
        postalCode: address.postalCode,
        country: address.country,
        phone: address.phone,
      },
      billingAddressSnapshot: {
        firstName: address.firstName,
        lastName: address.lastName,
        addressLine1: address.addressLine1,
        additionalInformation: address.additionalInformation,
        city: address.city,
        postalCode: address.postalCode,
        country: address.country,
      },
      stripeCheckoutSessionId: args.stripeCheckoutSessionId,
      stripePaymentIntentId: args.stripePaymentIntentId ?? undefined,
      shippoShipmentId: args.shipmentObjectId,
      shippingMethod: args.shippingMethod,
      shippingServiceCode: args.shippingServiceCode,
      carrier: args.carrier,
      createdAt: now,
      updatedAt: now,
      paidAt: now,
    });

    for (const item of orderItems) {
      await ctx.db.insert("orderItems", {
        orderId,
        variantId: item.variantId,
        productName: item.productName,
        variantName: item.variantName,
        sku: item.sku,
        quantity: item.quantity,
        unitPrice: item.unitPrice,
        totalPrice: item.unitPrice * item.quantity,
        imageUrl: item.imageUrl,
      });
    }

    for (const item of orderItems) {
      const variant = await ctx.db.get(item.variantId);
      if (variant) {
        await ctx.db.patch(item.variantId, {
          stockQuantity: variant.stockQuantity - item.quantity,
        });
      }
    }

    await ctx.db.patch(cart._id, { items: [], updatedAt: now });

    return orderId;
  },
});