import type { ExpressionBuilder, Transaction } from "kysely";
import { jsonArrayFrom } from "kysely/helpers/sqlite";
import * as R from "remeda";
import { db } from "~/db/sql";
import type { BuildWeapon, DB, Tables, TablesInsertable } from "~/db/tables";
import { modesShort } from "~/modules/in-game-lists/modes";
import type {
	Ability,
	BuildAbilitiesTuple,
	MainWeaponId,
	ModeShort,
} from "~/modules/in-game-lists/types";
import { weaponIdToArrayWithAlts } from "~/modules/in-game-lists/weapon-ids";
import { dateToDatabaseTimestamp } from "~/utils/dates";
import { LimitReachedError } from "~/utils/errors";
import invariant from "~/utils/invariant";
import { commonUserJsonObject } from "~/utils/kysely.server";
import { BUILD } from "./builds-constants";
import { sortAbilities } from "./core/ability-sorting.server";

export async function allByUserId(
	userId: number,
	options: {
		showPrivate?: boolean;
		sortAbilities?: boolean;
		limit?: number;
	} = {},
) {
	const {
		showPrivate = false,
		sortAbilities: shouldSortAbilities = false,
		limit,
	} = options;
	const rows = await db
		.selectFrom("Build")
		.select(({ eb }) => [
			"Build.id",
			"Build.title",
			"Build.description",
			"Build.modes",
			"Build.headGearSplId",
			"Build.clothesGearSplId",
			"Build.shoesGearSplId",
			"Build.updatedAt",
			"Build.private",
			jsonArrayFrom(
				eb
					.selectFrom("BuildWeapon")
					.select(["BuildWeapon.weaponSplId", "BuildWeapon.isTop500"])
					.orderBy("BuildWeapon.weaponSplId", "asc")
					.whereRef("BuildWeapon.buildId", "=", "Build.id"),
			).as("weapons"),
			withAbilities(eb),
		])
		.where("Build.ownerId", "=", userId)
		.$if(!showPrivate, (qb) => qb.where("Build.private", "=", 0))
		.$if(typeof limit === "number", (qb) => qb.limit(limit!))
		.orderBy("Build.updatedAt", "desc")
		.execute();

	return rows.map((row) => {
		const abilities = dbAbilitiesToArrayOfArrays(row.abilities);

		return {
			...row,
			abilities: shouldSortAbilities ? sortAbilities(abilities) : abilities,
		};
	});
}

const gearOrder: Array<Tables["BuildAbility"]["gearType"]> = [
	"HEAD",
	"CLOTHES",
	"SHOES",
];
function dbAbilitiesToArrayOfArrays(
	abilities: Array<
		Pick<Tables["BuildAbility"], "ability" | "gearType" | "slotIndex">
	>,
): BuildAbilitiesTuple {
	const sorted = R.sortBy(
		abilities,
		(a) => gearOrder.indexOf(a.gearType),
		(a) => a.slotIndex,
	).map((a) => a.ability);

	invariant(sorted.length === 12, "expected 12 abilities");

	return R.chunk(sorted, 4) as BuildAbilitiesTuple;
}

interface CreateArgs {
	ownerId: TablesInsertable["Build"]["ownerId"];
	title: TablesInsertable["Build"]["title"];
	description: TablesInsertable["Build"]["description"];
	modes: Array<ModeShort> | null;
	headGearSplId: number | null;
	clothesGearSplId: number | null;
	shoesGearSplId: number | null;
	weaponSplIds: Array<BuildWeapon["weaponSplId"]>;
	abilities: BuildAbilitiesTuple;
	private: TablesInsertable["Build"]["private"];
}

function serializeModes(modes: Array<ModeShort> | null) {
	if (!modes || modes.length === 0) return null;

	return JSON.stringify(
		modes.slice().sort((a, b) => modesShort.indexOf(a) - modesShort.indexOf(b)),
	);
}

async function createInTrx({
	args,
	trx,
}: {
	args: CreateArgs;
	trx: Transaction<DB>;
}) {
	const { id: buildId, updatedAt } = await trx
		.insertInto("Build")
		.values({
			ownerId: args.ownerId,
			title: args.title,
			description: args.description,
			modes: serializeModes(args.modes),
			headGearSplId: args.headGearSplId,
			clothesGearSplId: args.clothesGearSplId,
			shoesGearSplId: args.shoesGearSplId,
			private: args.private,
		})
		.returningAll()
		.executeTakeFirstOrThrow();

	await populateBuildChildrenInTrx({ trx, buildId, updatedAt, args });
}

async function populateBuildChildrenInTrx({
	trx,
	buildId,
	updatedAt,
	args,
}: {
	trx: Transaction<DB>;
	buildId: number;
	updatedAt: number;
	args: CreateArgs;
}) {
	await trx
		.insertInto("BuildWeapon")
		.values(
			args.weaponSplIds.map((weaponSplId) => ({
				buildId,
				weaponSplId,
			})),
		)
		.execute();

	await trx
		.updateTable("BuildWeapon")
		.set({ isTop500: 1 })
		.where("buildId", "=", buildId)
		.where(hasXRankPlacement)
		.execute();

	const tier =
		(
			await trx
				.selectFrom("PlusTier")
				.select("tier")
				.where("userId", "=", args.ownerId)
				.executeTakeFirst()
		)?.tier ?? 4;

	await trx
		.updateTable("BuildWeapon")
		.set({
			tier,
			updatedAt,
		})
		.where("buildId", "=", buildId)
		.execute();

	await trx
		.insertInto("BuildAbility")
		.values(
			args.abilities.flatMap((row, rowI) =>
				row.map((ability, abilityI) => ({
					buildId,
					gearType: rowI === 0 ? "HEAD" : rowI === 1 ? "CLOTHES" : "SHOES",
					ability,
					slotIndex: abilityI,
				})),
			),
		)
		.execute();
}

export async function create(args: CreateArgs) {
	return db.transaction().execute(async (trx) => {
		await createInTrx({ args, trx });

		const { count } = await trx
			.selectFrom("Build")
			.select((eb) => eb.fn.countAll<number>().as("count"))
			.where("ownerId", "=", args.ownerId)
			.executeTakeFirstOrThrow();

		if (count > BUILD.MAX_COUNT) {
			throw new LimitReachedError("Max amount of builds reached");
		}
	});
}

export async function update(args: CreateArgs & { id: number }) {
	return db.transaction().execute(async (trx) => {
		const { updatedAt } = await trx
			.updateTable("Build")
			.set({
				title: args.title,
				description: args.description,
				modes: serializeModes(args.modes),
				headGearSplId: args.headGearSplId,
				clothesGearSplId: args.clothesGearSplId,
				shoesGearSplId: args.shoesGearSplId,
				private: args.private,
				updatedAt: dateToDatabaseTimestamp(new Date()),
			})
			.where("id", "=", args.id)
			.returning("updatedAt")
			.executeTakeFirstOrThrow();

		await trx
			.deleteFrom("BuildWeapon")
			.where("buildId", "=", args.id)
			.execute();
		await trx
			.deleteFrom("BuildAbility")
			.where("buildId", "=", args.id)
			.execute();

		await populateBuildChildrenInTrx({
			trx,
			buildId: args.id,
			updatedAt,
			args,
		});
	});
}

export function deleteById(id: number) {
	return db.deleteFrom("Build").where("id", "=", id).execute();
}

export async function ownerIdById(buildId: number) {
	const result = await db
		.selectFrom("Build")
		.select("ownerId")
		.where("id", "=", buildId)
		.executeTakeFirstOrThrow();

	return result.ownerId;
}

export async function abilityPointAverages(weaponSplId?: MainWeaponId | null) {
	return db
		.selectFrom("BuildAbility")
		.select(({ fn }) => [
			"BuildAbility.ability",
			fn.sum<number>("BuildAbility.abilityPoints").as("abilityPointsSum"),
		])
		.innerJoin("Build", "Build.id", "BuildAbility.buildId")
		.$if(typeof weaponSplId === "number", (qb) =>
			qb
				.innerJoin("BuildWeapon", "BuildAbility.buildId", "BuildWeapon.buildId")
				.where("BuildWeapon.weaponSplId", "=", weaponSplId!),
		)
		.groupBy("BuildAbility.ability")
		.where("Build.private", "=", 0)
		.execute();
}

export async function popularAbilitiesByWeaponId(weaponSplId: MainWeaponId) {
	const result = await db
		.selectFrom("BuildWeapon")
		.innerJoin("Build", "Build.id", "BuildWeapon.buildId")
		.select((eb) => [
			jsonArrayFrom(
				eb
					.selectFrom("BuildAbility")
					.select(["BuildAbility.ability", "BuildAbility.abilityPoints"])
					.whereRef("BuildAbility.buildId", "=", "BuildWeapon.buildId"),
			).as("abilities"),
		])
		.where("BuildWeapon.weaponSplId", "=", weaponSplId)
		.where("Build.private", "=", 0)
		.groupBy("Build.ownerId") // consider only one build per user
		.execute();

	return result as Array<{
		abilities: Array<{
			ability: Ability;
			abilityPoints: number;
		}>;
	}>;
}

export type AverageAbilityPointsResult = Awaited<
	ReturnType<typeof abilityPointAverages>
>[number];

export type AbilitiesByWeapon = Awaited<
	ReturnType<typeof popularAbilitiesByWeaponId>
>[number];

export async function allByWeaponId(
	weaponId: MainWeaponId,
	options: { limit: number; sortAbilities?: boolean },
) {
	const { limit, sortAbilities: shouldSortAbilities = false } = options;
	const weaponIds = weaponIdToArrayWithAlts(weaponId);

	// For weapons with alts, run separate queries and merge.
	// This allows each query to use the covering index for ordering,
	// which is ~6x faster than using IN with multiple values.
	const allResults = await Promise.all(
		weaponIds.map((id) => buildsByWeaponIdQuery(id, limit)),
	);

	const rows = R.pipe(
		allResults.flat(),
		R.sortBy(
			(row) => row.bwTier,
			[(row) => row.bwIsTop500, "desc"],
			[(row) => row.bwUpdatedAt, "desc"],
		),
		R.uniqueBy((row) => row.id),
		R.take(limit),
	);

	return rows.map((row) => {
		const abilities = dbAbilitiesToArrayOfArrays(row.abilities);

		return {
			...row,
			abilities: shouldSortAbilities ? sortAbilities(abilities) : abilities,
		};
	});
}

function buildsByWeaponIdQuery(weaponSplId: MainWeaponId, limit: number) {
	return db
		.selectFrom("BuildWeapon")
		.innerJoin("Build", "Build.id", "BuildWeapon.buildId")
		.innerJoin("User", "User.id", "Build.ownerId")
		.leftJoin("PlusTier", "PlusTier.userId", "Build.ownerId")
		.select(({ eb }) => [
			"Build.id",
			"Build.title",
			"Build.description",
			"Build.modes",
			"Build.headGearSplId",
			"Build.clothesGearSplId",
			"Build.shoesGearSplId",
			"Build.updatedAt",
			"Build.private",
			"PlusTier.tier as plusTier",
			"BuildWeapon.tier as bwTier",
			"BuildWeapon.isTop500 as bwIsTop500",
			"BuildWeapon.updatedAt as bwUpdatedAt",
			withAbilities(eb),
			jsonArrayFrom(
				eb
					.selectFrom("BuildWeapon as BuildWeaponInner")
					.select(["BuildWeaponInner.weaponSplId", "BuildWeaponInner.isTop500"])
					.orderBy("BuildWeaponInner.weaponSplId", "asc")
					.whereRef("BuildWeaponInner.buildId", "=", "Build.id"),
			).as("weapons"),
			commonUserJsonObject(eb).as("owner"),
		])
		.where("Build.private", "=", 0)
		.where("BuildWeapon.weaponSplId", "=", weaponSplId)
		.orderBy("BuildWeapon.tier", "asc")
		.orderBy("BuildWeapon.isTop500", "desc")
		.orderBy("BuildWeapon.updatedAt", "desc")
		.limit(limit)
		.execute();
}

function withAbilities(eb: ExpressionBuilder<DB, "Build">) {
	return jsonArrayFrom(
		eb
			.selectFrom("BuildAbility")
			.select([
				"BuildAbility.gearType",
				"BuildAbility.ability",
				"BuildAbility.slotIndex",
			])
			.whereRef("BuildAbility.buildId", "=", "Build.id"),
	).as("abilities");
}

function hasXRankPlacement(eb: ExpressionBuilder<DB, "BuildWeapon">) {
	return eb.exists(
		eb
			.selectFrom("Build")
			.select("BuildWeapon.buildId")
			.innerJoin("SplatoonPlayer", "SplatoonPlayer.userId", "Build.ownerId")
			.innerJoin(
				"XRankPlacement",
				"XRankPlacement.playerId",
				"SplatoonPlayer.id",
			)
			.whereRef("Build.id", "=", "BuildWeapon.buildId")
			.whereRef("XRankPlacement.weaponSplId", "=", "BuildWeapon.weaponSplId"),
	);
}

/** Recalculates which build weapons are top 500 based on latest X Rank placements data. */
export async function recalculateAllTop500() {
	await db.transaction().execute(async (trx) => {
		await trx.updateTable("BuildWeapon").set({ isTop500: 0 }).execute();

		await trx
			.updateTable("BuildWeapon")
			.set({ isTop500: 1 })
			.where(hasXRankPlacement)
			.execute();
	});
}

export async function recalculateAllTiers() {
	await db.transaction().execute(async (trx) => {
		await trx
			.updateTable("BuildWeapon")
			.set({
				tier: 4,
			})
			.execute();

		for (const tier of [3, 2, 1]) {
			const tierMembers = (
				await trx
					.selectFrom("PlusTier")
					.select("userId")
					.where("tier", "=", tier)
					.execute()
			).map((r) => r.userId);

			await trx
				.updateTable("BuildWeapon")
				.set({ tier })
				.where("BuildWeapon.buildId", "in", (eb) =>
					eb
						.selectFrom("Build")
						.select("Build.id")
						.where("Build.ownerId", "in", tierMembers),
				)
				.execute();
		}
	});
}