import fs from "fs/promises";
import path from "path";
import * as f from "fp-ts";
import * as t from "io-ts";

export const E926DedupeEntryC = t.type({
    provider: t.literal("e926"),
    id: t.number,
});

export const DedupeEntryC = E926DedupeEntryC;

export type E926DedupeEntry = t.TypeOf<typeof E926DedupeEntryC>;

export type DedupeEntry = t.TypeOf<typeof DedupeEntryC>;

export class Dedupe {
    private entries: DedupeEntry[] = [];

    private readonly filePath: string;

    private isLoaded = false;

    constructor(private max: number, filename: string) {
        this.filePath = path.join(process.cwd(), filename);
    }

    private async load() {
        if (this.isLoaded) {
            return;
        }

        try {
            await fs.stat(this.filePath);
        } catch {
            await this.save();
        }

        const fileContent = await fs.readFile(this.filePath, "utf8");
        const entries = t.array(DedupeEntryC).decode(fileContent);

        if (f.either.isRight(entries)) {
            this.entries = entries.right;
        }
    }

    private async save() {
        await fs.writeFile(this.filePath, JSON.stringify(this.entries ?? []), "utf8");
    }

    async check(entry: DedupeEntry) {
        await this.load();

        const has = !!this.entries.find((e) => e.provider === entry.provider && e.id === entry.id);

        if (!has) {
            this.entries.push(entry);
            await this.save();
        }

        return has;
    }
}

export default new Dedupe(50, "dedupe.json");