import { TRPCError } from "@trpc/server";
import { z } from "zod";
import {
  and,
  asc,
  eq,
  getTableColumns,
  inArray,
  isNull,
  sql,
} from "drizzle-orm";
import { objectTypes } from "@tasks/shared";
import {
  objectAssignees,
  objects,
} from "@tasks/database/schema";
import { router, protectedProcedure } from "@/server/trpc";

const objectTypeSchema = z.enum(objectTypes);

const TREE_TYPES = ["project", "group", "document", "whiteboard"] as const;

export type ObjectTreeNode = {
  id: string;
  title: string;
  type: string;
  icon: string | null;
  parentId: string | null;
  childCount: number;
  children: ObjectTreeNode[];
};

export const objectsRouter = router({
  list: protectedProcedure
    .input(
      z.object({
        workspaceId: z.string().uuid(),
        parentId: z.string().uuid().nullable().optional(),
        type: objectTypeSchema.optional(),
        status: z.string().optional(),
        limit: z.number().int().positive().max(500).optional(),
        offset: z.number().int().nonnegative().optional(),
      }),
    )
    .query(async ({ ctx, input }) => {
      const limit = input.limit ?? 50;
      const offset = input.offset ?? 0;

      const conditions = [
        eq(objects.workspaceId, input.workspaceId),
        isNull(objects.archivedAt),
      ];

      if (input.parentId === null) {
        conditions.push(isNull(objects.parentId));
      } else if (input.parentId !== undefined) {
        conditions.push(eq(objects.parentId, input.parentId));
      }

      if (input.type !== undefined) {
        conditions.push(eq(objects.type, input.type));
      }
      if (input.status !== undefined) {
        conditions.push(eq(objects.status, input.status));
      }

      const rows = await ctx.db
        .select({
          ...getTableColumns(objects),
          assigneeCount: sql<number>`(
            select count(*)::int from object_assignees
            where object_id = ${objects.id}
          )`.mapWith(Number),
        })
        .from(objects)
        .where(and(...conditions))
        .orderBy(asc(objects.sortOrder), asc(objects.id))
        .limit(limit)
        .offset(offset);

      return { objects: rows };
    }),

  getById: protectedProcedure
    .input(z.object({ id: z.string().uuid() }))
    .query(async ({ ctx, input }) => {
      const obj = await ctx.db.query.objects.findFirst({
        where: eq(objects.id, input.id),
        with: {
          children: true,
          assignees: {
            with: {
              user: true,
            },
          },
          propertyValues: {
            with: {
              propertyDefinition: true,
            },
          },
        },
      });

      if (!obj) {
        throw new TRPCError({ code: "NOT_FOUND", message: "Object not found" });
      }

      const children = [...obj.children].sort((a, b) => {
        if (a.sortOrder !== b.sortOrder) {
          return a.sortOrder - b.sortOrder;
        }
        return a.id.localeCompare(b.id);
      });

      return { ...obj, children };
    }),

  getTree: protectedProcedure
    .input(
      z.object({
        workspaceId: z.string().uuid(),
        maxDepth: z.number().int().positive().max(100).optional(),
      }),
    )
    .query(async ({ ctx, input }) => {
      const maxDepth = input.maxDepth ?? 50;

      const rows = await ctx.db
        .select()
        .from(objects)
        .where(
          and(
            eq(objects.workspaceId, input.workspaceId),
            inArray(objects.type, [...TREE_TYPES]),
            isNull(objects.archivedAt),
          ),
        )
        .orderBy(asc(objects.sortOrder), asc(objects.id));

      const ids = new Set(rows.map((r) => r.id));

      const childCountMap = new Map<string, number>();
      for (const row of rows) {
        if (row.parentId) {
          childCountMap.set(
            row.parentId,
            (childCountMap.get(row.parentId) ?? 0) + 1,
          );
        }
      }

      function buildTree(parentId: string | null, depth: number): ObjectTreeNode[] {
        if (depth > maxDepth) {
          return [];
        }

        const directChildren = rows.filter((r) => r.parentId === parentId);

        return directChildren.map((r) => ({
          id: r.id,
          title: r.title,
          type: r.type,
          icon: r.icon,
          parentId: r.parentId,
          childCount: childCountMap.get(r.id) ?? 0,
          children: buildTree(r.id, depth + 1),
        }));
      }

      const roots = rows.filter(
        (r) => r.parentId === null || !ids.has(r.parentId),
      );

      const tree: ObjectTreeNode[] = roots.map((r) => ({
        id: r.id,
        title: r.title,
        type: r.type,
        icon: r.icon,
        parentId: r.parentId,
        childCount: childCountMap.get(r.id) ?? 0,
        children: buildTree(r.id, 1),
      }));

      return { tree };
    }),

  create: protectedProcedure
    .input(
      z.object({
        type: objectTypeSchema,
        title: z.string().min(1).max(500),
        parentId: z.string().uuid().nullable().optional(),
        workspaceId: z.string().uuid(),
        description: z.string().optional(),
        icon: z.string().optional(),
        status: z.string().optional(),
        templateId: z.string().uuid().nullable().optional(),
      }),
    )
    .mutation(async ({ ctx, input }) => {
      const userId = ctx.session.user.id;
      if (!userId) {
        throw new TRPCError({
          code: "UNAUTHORIZED",
          message: "Missing user id",
        });
      }

      const [created] = await ctx.db
        .insert(objects)
        .values({
          type: input.type,
          title: input.title,
          parentId: input.parentId ?? null,
          workspaceId: input.workspaceId,
          description: input.description,
          icon: input.icon,
          status: input.status,
          templateId: input.templateId ?? null,
          createdBy: userId,
        })
        .returning();

      if (!created) {
        throw new TRPCError({
          code: "INTERNAL_SERVER_ERROR",
          message: "Failed to create object",
        });
      }

      return created;
    }),

  update: protectedProcedure
    .input(
      z.object({
        id: z.string().uuid(),
        title: z.string().min(1).max(500).optional(),
        description: z.string().nullable().optional(),
        icon: z.string().nullable().optional(),
        status: z.string().nullable().optional(),
        coverImage: z.string().nullable().optional(),
        content: z.any().optional(),
      }),
    )
    .mutation(async ({ ctx, input }) => {
      const { id, ...patch } = input;
      const updatedAt = new Date();

      const [updated] = await ctx.db
        .update(objects)
        .set({
          ...(patch.title !== undefined ? { title: patch.title } : {}),
          ...(patch.description !== undefined ? { description: patch.description } : {}),
          ...(patch.icon !== undefined ? { icon: patch.icon } : {}),
          ...(patch.status !== undefined ? { status: patch.status } : {}),
          ...(patch.coverImage !== undefined ? { coverImage: patch.coverImage } : {}),
          ...(patch.content !== undefined ? { content: patch.content } : {}),
          updatedAt,
        })
        .where(eq(objects.id, id))
        .returning();

      if (!updated) {
        throw new TRPCError({ code: "NOT_FOUND", message: "Object not found" });
      }

      return updated;
    }),

  archive: protectedProcedure
    .input(z.object({ id: z.string().uuid() }))
    .mutation(async ({ ctx, input }) => {
      const archivedAt = new Date();
      const [row] = await ctx.db
        .update(objects)
        .set({ archivedAt, updatedAt: archivedAt })
        .where(eq(objects.id, input.id))
        .returning();

      if (!row) {
        throw new TRPCError({ code: "NOT_FOUND", message: "Object not found" });
      }

      return row;
    }),

  reorder: protectedProcedure
    .input(
      z.object({
        id: z.string().uuid(),
        sortOrder: z.number().int(),
        newParentId: z.string().uuid().nullable().optional(),
      }),
    )
    .mutation(async ({ ctx, input }) => {
      const updates: {
        sortOrder: number;
        updatedAt: Date;
        parentId?: string | null;
      } = {
        sortOrder: input.sortOrder,
        updatedAt: new Date(),
      };

      if (input.newParentId !== undefined) {
        updates.parentId = input.newParentId;
      }

      const [row] = await ctx.db
        .update(objects)
        .set(updates)
        .where(eq(objects.id, input.id))
        .returning();

      if (!row) {
        throw new TRPCError({ code: "NOT_FOUND", message: "Object not found" });
      }

      return row;
    }),

  assign: protectedProcedure
    .input(
      z.object({
        objectId: z.string().uuid(),
        userId: z.string().uuid(),
        role: z.string().max(50).optional(),
        action: z.enum(["add", "remove"]),
      }),
    )
    .mutation(async ({ ctx, input }) => {
      if (input.action === "remove") {
        const deleted = await ctx.db
          .delete(objectAssignees)
          .where(
            and(
              eq(objectAssignees.objectId, input.objectId),
              eq(objectAssignees.userId, input.userId),
            ),
          )
          .returning({ id: objectAssignees.id });

        if (deleted.length === 0) {
          throw new TRPCError({
            code: "NOT_FOUND",
            message: "Assignee not found",
          });
        }

        return { ok: true as const, action: "remove" as const };
      }

      const role = input.role ?? "assignee";

      await ctx.db
        .insert(objectAssignees)
        .values({
          objectId: input.objectId,
          userId: input.userId,
          role,
        })
        .onConflictDoUpdate({
          target: [objectAssignees.objectId, objectAssignees.userId],
          set: { role },
        });

      return { ok: true as const, action: "add" as const };
    }),
});