import { initTRPC, TRPCError } from "@trpc/server";
import { z } from "zod";
import superjson from "superjson";
import type { Session } from "next-auth";
import { db } from "@tasks/database";
import { auth } from "@/lib/auth";
import { resolveWorkspace, type WorkspaceContext } from "@/server/lib/resolve-workspace";

export type Context = {
  db: typeof db;
  session: Session | null;
};

export async function createContext(): Promise<Context> {
  try {
    const session = await auth();
    return { db, session };
  } catch (error) {
    console.error("[trpc] createContext failed:", error);
    throw new TRPCError({
      code: "INTERNAL_SERVER_ERROR",
      message: "Failed to create request context",
      cause: error,
    });
  }
}

const t = initTRPC.context<Context>().create({
  transformer: superjson,
  // Expose `error.cause` to the client. Procedures that need to surface
  // structured failure modes (e.g. `invites.accept` returning the invited
  // email so the explainer page can render) pass a `{ reason, ... }` object
  // as the cause and the client reads it from `error.shape.data.cause`.
  // Anything thrown should still be safe to serialize (no class instances,
  // no DB rows, no secrets) — keep cause payloads small and pure data.
  errorFormatter: ({ shape, error }) => ({
    ...shape,
    data: {
      ...shape.data,
      cause:
        error.cause && typeof error.cause === "object" && !(error.cause instanceof Error)
          ? (error.cause as Record<string, unknown>)
          : undefined,
    },
  }),
});

export const isAuthed = t.middleware(({ ctx, next }) => {
  if (!ctx.session?.user) {
    throw new TRPCError({ code: "UNAUTHORIZED" });
  }
  return next({
    ctx: {
      ...ctx,
      session: ctx.session,
    },
  });
});

export const router = t.router;
export const createCallerFactory = t.createCallerFactory;
export const publicProcedure = t.procedure;
export const protectedProcedure = t.procedure.use(isAuthed);

/**
 * Procedure for any tenant-scoped operation. Caller must:
 *   - Be authenticated.
 *   - Pass `workspace` (UUID or slug) in the input. The middleware resolves it
 *     to a full `WorkspaceContext` (id, slug, name, owner, role) and exposes it
 *     on `ctx.workspace`. Procedures can then scope queries by `ctx.workspace.id`.
 *
 * Example:
 *   workspaceProcedure
 *     .input(z.object({ workspace: z.string(), title: z.string() }))
 *     .mutation(({ ctx, input }) => {
 *       return ctx.db.insert(objects).values({
 *         workspaceId: ctx.workspace.id,
 *         title: input.title,
 *         type: "task",
 *       });
 *     });
 */
export const workspaceProcedure = protectedProcedure
  .input(z.object({ workspace: z.string().min(1) }))
  .use(async ({ ctx, input, next }) => {
    const ws = await resolveWorkspace({
      handle: input.workspace,
      userId: ctx.session.user.id,
      db: ctx.db,
    });
    return next({
      ctx: {
        ...ctx,
        workspace: ws,
      },
    });
  });

export type WorkspaceProcedureContext = Context & { session: Session; workspace: WorkspaceContext };