import { experimental_trpcMiddleware, TRPCError } from "@trpc/server";
import { and, desc, eq, inArray, notExists } from "drizzle-orm";
import { z } from "zod";

import { SqliteError } from "@lifetracker/db";
import { categories, colors } from "@lifetracker/db/schema";
import {
    ZCategories,
    zCategorySchema,
    ZCreateCategories,
    zCreateCategorySchema,
    zGetCategoryResponseSchema,
    zUpdateCategoryRequestSchema
} from "@lifetracker/shared/types/categories";
import type { Context } from "../index";
import { authedProcedure, router } from "../index";
import { zColorSchema } from "@lifetracker/shared/types/colors";


function conditionFromInput(input: { categoryCode?: string, categoryId?: string }, userId: string) {
    const queryType = input.categoryCode ? eq(categories.code, input.categoryCode) : eq(categories.id, input.categoryId);
    return and(queryType, eq(categories.userId, userId));
}

async function createCategory(
    input: z.infer<typeof zCategorySchema>,
    ctx: Context,
) {

    return ctx.db.transaction(async (trx) => {
        try {
            const result = await trx
                .insert(categories)
                .values({
                    name: input.name,
                    code: input.code,
                    description: input.description,
                    colorId: input.color.id,
                    userId: ctx.user!.id,
                    parentId: input.parentId ?? undefined
                })
                .returning({
                    id: categories.id,
                    name: categories.name,
                    code: categories.code,
                    description: categories.description,
                    colorId: categories.colorId
                });
            const { colorId, ...newCategory } = result[0];

            return {
                color: input.color,
                ...newCategory
            };

        } catch (e) {
            if (e instanceof SqliteError) {
                if (e.code == "SQLITE_CONSTRAINT_UNIQUE") {
                    throw new TRPCError({
                        code: "BAD_REQUEST",
                        message: "There's already a category with this code",
                    });
                }
            }
            throw new TRPCError({
                code: "INTERNAL_SERVER_ERROR",
                message: "Something went wrong",
            });
        }
    });
}

export const categoriesAppRouter = router({
    categoryStats: authedProcedure
        .output(
            z.record(
                z.string(),
                z.object({
                    numEntries: z.number(),
                }),
            ),
        )
        .query(async ({ ctx }) => {
            const [categoryIds] = await Promise.all([
                ctx.db.select({ id: categories.id }).from(categories)
            ]);

            const results: Record<
                string,
                { numEntries: number }
            > = {};
            for (const category of categoryIds) {
                results[category.id] = {
                    numEntries: 3330,
                };
            }
            return results;
        }),
    list: authedProcedure
        .output(
            z.object({
                categories: z.array(
                    z.object({
                        id: z.string(),
                        code: z.number(),
                        name: z.string(),
                        description: z.string().optional(),
                        color: zColorSchema,
                    }),
                ),
            }),
        )
        .query(async ({ ctx }) => {
            const dbCategories = await ctx.db
                .select({
                    id: categories.id,
                    code: categories.code,
                    name: categories.name,
                    description: categories.description,
                    color: {
                        name: colors.name,
                        hexcode: colors.hexcode,
                        inverse: colors.inverse
                    }
                })
                .from(categories)
                .leftJoin(colors, eq(categories.colorId, colors.id))
                ;

            return {
                categories: dbCategories.map(({ color, ...category }) => ({
                    ...category,
                    color,
                })),
            };
        }),
    get: authedProcedure
        .input(
            z.object({
                categoryCode: z.number(),
            }),
        )
        .output(zCategorySchema)
        .query(async ({ input, ctx }) => {
            const res = await ctx.db
                .select({
                    id: categories.id,
                    code: categories.code,
                    name: categories.name,
                    description: categories.description,
                    colorId: categories.colorId,
                    parentId: categories.parentId,
                    userId: categories.userId,
                })
                .from(categories)
                .where(
                    and(
                        conditionFromInput(input, ctx.user.id),
                        eq(categories.userId, ctx.user.id),
                    ),
                );

            if (res.length == 0) {
                throw new TRPCError({ code: "NOT_FOUND" });
            }

            const numEntriesWithCategory = res.reduce<
                Record<ZCategorizedByEnum, number>
            >(
                (acc, curr) => {
                    if (curr.categorizedBy) {
                        acc[curr.categorizedBy]++;
                    }
                    return acc;
                },
                { ai: 0, human: 0 },
            );

            const [color] = await ctx.db.select().from(colors).where(
                and(
                    and(eq(colors.id, res[0].colorId), eq(colors.userId, res[0].userId)),
                    eq(res[0].userId, ctx.user.id),
                )
            );

            const categoryId: string = res[0].id;

            const { id, ...categoryProps } = res[0];
            const category: ZCategories = {
                color: color,
                ...categoryProps
            };

            if (category.parentId == null) {
                category.parentId = categoryId;
            }

            return category;
        }),
    create: authedProcedure
        .input(zCategorySchema)
        .output(
            z.object({
                id: z.string(),
                code: z.number(),
                name: z.string(),
                color: zColorSchema,
                description: z.string().optional(),
            }),
        )
        .mutation(async ({ input, ctx }) => {
            return createCategory(input, ctx);
        }),
    update: authedProcedure
        .input(zUpdateCategoryRequestSchema)
        .output(
            z.object({
                id: z.string(),
                name: z.string(),
                userId: z.string(),
                createdAt: z.date(),
            }),
        )
        .mutation(async ({ input, ctx }) => {
            const colorIdQuery = await ctx.db.select({ id: colors.id }).from(colors).where(
                and(
                    eq(colors.name, input.color.name),
                    eq(colors.userId, ctx.user.id),
                )
            );
            const res = await ctx.db
                .update(categories)
                .set({
                    name: input.name,
                    description: input.description,
                    code: input.code,
                    colorId: colorIdQuery[0].id,
                })
                .where(
                    and(
                        conditionFromInput({ categoryId: input.categoryId }, ctx.user.id),
                        eq(categories.userId, ctx.user.id),
                    ),
                ).returning();
            return res[0];
        }),
    delete: authedProcedure
        .input(
            z.object({
                categoryCode: z.number(),
            }),
        )
        .mutation(async ({ input, ctx }) => {
            //   const affectedBookmarks = await ctx.db
            //     .select({
            //       bookmarkId: tagsOnBookmarks.bookmarkId,
            //     })
            //     .from(tagsOnBookmarks)
            //     .where(
            //       and(
            //         eq(tagsOnBookmarks.tagId, input.tagId),
            //         // Tag ownership is checked in the ensureTagOwnership middleware
            //         // eq(bookmarkTags.userId, ctx.user.id),
            //       ),
            //     );

            const res = await ctx.db
                .delete(categories)
                .where(conditionFromInput(input, ctx.user.id));
            if (res.changes == 0) {
                throw new TRPCError({ code: "NOT_FOUND" });
            }
        }),
});