import { z } from "zod";
import { eq } from "drizzle-orm";
import { createTRPCRouter, protectedProcedure } from "../trpc";
import {
  recurringInvoices,
  recurringInvoiceItems,
  clients,
  businesses,
} from "~/server/db/schema";
import { TRPCError } from "@trpc/server";
import {
  generateInvoiceFromRecurring,
  nextDueDate,
} from "~/server/services/recurring-invoices";

const scheduleEnum = z.enum(["weekly", "biweekly", "monthly", "quarterly", "yearly"]);

const recurringItemSchema = z.object({
  description: z.string().min(1),
  hours: z.number().min(0),
  rate: z.number().min(0),
  position: z.number().int().default(0),
});

const recurringInvoiceSchema = z.object({
  name: z.string().min(1).max(255),
  clientId: z.string().min(1),
  businessId: z.string().optional().or(z.literal("")),
  schedule: scheduleEnum,
  invoicePrefix: z.string().optional().default("#"),
  taxRate: z.number().min(0).max(100).default(0),
  currency: z.string().length(3).default("USD"),
  notes: z.string().optional().or(z.literal("")),
  emailMessage: z.string().optional().or(z.literal("")),
  items: z.array(recurringItemSchema).min(1),
});

export const recurringInvoicesRouter = createTRPCRouter({
  getAll: protectedProcedure.query(async ({ ctx }) => {
    return ctx.db.query.recurringInvoices.findMany({
      where: eq(recurringInvoices.createdById, ctx.session.user.id),
      with: { client: true, business: true, items: true },
      orderBy: (r, { asc }) => [asc(r.nextDueAt)],
    });
  }),

  create: protectedProcedure
    .input(recurringInvoiceSchema)
    .mutation(async ({ ctx, input }) => {
      const client = await ctx.db.query.clients.findFirst({
        where: eq(clients.id, input.clientId),
      });
      if (client?.createdById !== ctx.session.user.id) {
        throw new TRPCError({ code: "BAD_REQUEST", message: "Client not found" });
      }
      if (input.businessId) {
        const biz = await ctx.db.query.businesses.findFirst({
          where: eq(businesses.id, input.businessId),
        });
        if (biz?.createdById !== ctx.session.user.id) {
          throw new TRPCError({ code: "BAD_REQUEST", message: "Business not found" });
        }
      }

      const [rec] = await ctx.db
        .insert(recurringInvoices)
        .values({
          name: input.name,
          clientId: input.clientId,
          businessId: input.businessId ?? null,
          schedule: input.schedule,
          status: "active",
          invoicePrefix: input.invoicePrefix,
          taxRate: input.taxRate,
          currency: input.currency,
          notes: input.notes ?? null,
          emailMessage: input.emailMessage ?? null,
          nextDueAt: nextDueDate(input.schedule),
          createdById: ctx.session.user.id,
        })
        .returning({ id: recurringInvoices.id });

      if (!rec) throw new TRPCError({ code: "INTERNAL_SERVER_ERROR" });

      await ctx.db.insert(recurringInvoiceItems).values(
        input.items.map((item, idx) => ({
          recurringInvoiceId: rec.id,
          description: item.description,
          hours: item.hours,
          rate: item.rate,
          position: item.position ?? idx,
        })),
      );

      return rec;
    }),

  update: protectedProcedure
    .input(recurringInvoiceSchema.extend({ id: z.string() }))
    .mutation(async ({ ctx, input }) => {
      const existing = await ctx.db.query.recurringInvoices.findFirst({
        where: eq(recurringInvoices.id, input.id),
      });
      if (existing?.createdById !== ctx.session.user.id) {
        throw new TRPCError({ code: "NOT_FOUND" });
      }

      await ctx.db
        .update(recurringInvoices)
        .set({
          name: input.name,
          clientId: input.clientId,
          businessId: input.businessId ?? null,
          schedule: input.schedule,
          invoicePrefix: input.invoicePrefix,
          taxRate: input.taxRate,
          currency: input.currency,
          notes: input.notes ?? null,
          emailMessage: input.emailMessage ?? null,
        })
        .where(eq(recurringInvoices.id, input.id));

      await ctx.db
        .delete(recurringInvoiceItems)
        .where(eq(recurringInvoiceItems.recurringInvoiceId, input.id));

      await ctx.db.insert(recurringInvoiceItems).values(
        input.items.map((item, idx) => ({
          recurringInvoiceId: input.id,
          description: item.description,
          hours: item.hours,
          rate: item.rate,
          position: item.position ?? idx,
        })),
      );

      return { success: true };
    }),

  pause: protectedProcedure
    .input(z.object({ id: z.string() }))
    .mutation(async ({ ctx, input }) => {
      const rec = await ctx.db.query.recurringInvoices.findFirst({
        where: eq(recurringInvoices.id, input.id),
      });
      if (rec?.createdById !== ctx.session.user.id) {
        throw new TRPCError({ code: "NOT_FOUND" });
      }
      await ctx.db
        .update(recurringInvoices)
        .set({ status: "paused" })
        .where(eq(recurringInvoices.id, input.id));
      return { success: true };
    }),

  resume: protectedProcedure
    .input(z.object({ id: z.string() }))
    .mutation(async ({ ctx, input }) => {
      const rec = await ctx.db.query.recurringInvoices.findFirst({
        where: eq(recurringInvoices.id, input.id),
      });
      if (rec?.createdById !== ctx.session.user.id) {
        throw new TRPCError({ code: "NOT_FOUND" });
      }
      await ctx.db
        .update(recurringInvoices)
        .set({ status: "active" })
        .where(eq(recurringInvoices.id, input.id));
      return { success: true };
    }),

  delete: protectedProcedure
    .input(z.object({ id: z.string() }))
    .mutation(async ({ ctx, input }) => {
      const rec = await ctx.db.query.recurringInvoices.findFirst({
        where: eq(recurringInvoices.id, input.id),
      });
      if (rec?.createdById !== ctx.session.user.id) {
        throw new TRPCError({ code: "NOT_FOUND" });
      }
      await ctx.db
        .delete(recurringInvoices)
        .where(eq(recurringInvoices.id, input.id));
      return { success: true };
    }),

  generateNow: protectedProcedure
    .input(z.object({ id: z.string() }))
    .mutation(async ({ ctx, input }) => {
      const rec = await ctx.db.query.recurringInvoices.findFirst({
        where: eq(recurringInvoices.id, input.id),
        with: { items: true },
      });
      if (rec?.createdById !== ctx.session.user.id) {
        throw new TRPCError({ code: "NOT_FOUND" });
      }

      const newInvoice = await generateInvoiceFromRecurring(ctx.db, rec);

      await ctx.db
        .update(recurringInvoices)
        .set({ lastGeneratedAt: new Date(), nextDueAt: nextDueDate(rec.schedule) })
        .where(eq(recurringInvoices.id, input.id));

      return { invoiceId: newInvoice.id };
    }),
});