import Decimal, { DecimalSource } from "break_eternity.js";
import { Resource, Resources, SerializedConverter, SerializedNodeBehaviour as SerializedBehaviour, SerializedNodeBehaviour } from "../../types";

export type BehaviourResourcePin = {
    resource: Resource;
}

export type BehaviourSocket = {
    type: 'input' | 'output';
    index: number; // within its type
    resource: Resource;
}

export type BehaviourLink = {
    target: Behaviour['id'],
    resource: Resource;
}

export type BehaviourInput = BehaviourResourcePin & {
    link: BehaviourLink;
}

export type BehaviourInputs = {
    pins: BehaviourInput[];
}

export type BehaviourOutput = BehaviourResourcePin & {
}

export type BehaviourOutputs = {
    pins: BehaviourOutput[];
}

export type BehaviourDisplayInfo = {
    storages: Record<string, Resources>;
    sockets: BehaviourSocket[];
    links: BehaviourLink[];

    [x: string]: unknown;
}

export abstract class Behaviour {
    public readonly id: string;
    public readonly kind: string;
    public readonly inputs: BehaviourInputs;
    public readonly outputs: BehaviourOutputs;

    constructor(source: SerializedBehaviour) {
        this.id = source.id;
        this.kind = source.kind;
        this.outputs = {
            pins: source.outputs.pins.map((output) => ({
                resource: output.resource,
            })),
        }
        this.inputs = {
            pins: source.inputs.pins.map((input) => ({
                resource: input.resource,
                link: input.link,
            })),
        }
    }

    public getDisplayInfo(): BehaviourDisplayInfo {
        return {
            storages: {},
            links: this.inputs.pins.map((input) => input.link),
            sockets: [
                ...this.inputs.pins.map((input, index) => ({
                    type: 'input',
                    index,
                    resource: input.resource,
                } satisfies BehaviourSocket)),
                ...this.outputs.pins.map((output, index) => ({
                    type: 'output',
                    index,
                    resource: output.resource,
                } satisfies BehaviourSocket)),
            ],
        };
    }

    /** Withdraws up to `amount` of `resource` from this behaviour's storage, returning how much was actually taken. */
    public abstract take(resource: Resource, amount: DecimalSource): Decimal;

    protected abstract give(resource: Resource, amount: DecimalSource): void;

    abstract produce(times: DecimalSource): void;

    /** Pulls into this behaviour's own storage the same number of cycles this tick's `tick()` call just completed. */
    abstract pull(resolve: (id: string) => Behaviour | undefined): void;

    abstract reset(): void;

    abstract tick(deltaTime: number): void;
}

export class Converter extends Behaviour {
    protected readonly storage: Partial<Resources>;
    public cycleTime: Decimal;
    public readonly cycleLength: Decimal;
    public readonly inputRates: Partial<Resources>;
    public readonly outputRates: Partial<Resources>;
    /** Number of full cycles completed by the most recent `tick()` call, consumed by `pull()`. */
    private pendingCycles: Decimal = Decimal.dZero;

    constructor(source: SerializedNodeBehaviour & SerializedConverter) {
        if (source.kind !== 'converter')
            throw new Error('Invalid source');
        super(source);

        this.cycleTime = new Decimal(source.cycleTime);
        this.cycleLength = new Decimal(source.rules.cycleLength);

        this.storage = {};
        for (const [res, amount] of Object.entries(source.storage ?? {}))
            this.storage[res as Resource] = new Decimal(amount);

        this.inputRates = {};
        for (const [res, rate] of Object.entries(source.rules.inputRates ?? {}))
            this.inputRates[res as Resource] = new Decimal(rate);

        this.outputRates = {};
        for (const [res, rate] of Object.entries(source.rules.outputRates ?? {}))
            this.outputRates[res as Resource] = new Decimal(rate);
    }

    public tick(deltaTime: number): void {
        this.cycleTime = this.cycleTime.add(deltaTime);
        const fullCycles = this.cycleTime.div(this.cycleLength).floor();
        this.cycleTime = this.cycleTime.sub(fullCycles.mul(this.cycleLength));

        this.pendingCycles = fullCycles;
        this.produce(fullCycles);
    }

    /** Fills this converter's own storage from its outputs' production rates. */
    public produce(times: DecimalSource): void {
        for (const output of this.outputs.pins)
            this.give(output.resource, (this.outputRates[output.resource] ?? Decimal.dZero).mul(times));
    }

    /** Pulls resources into this converter's storage from whatever each input pin is linked to, scaled by the cycles this tick's `tick()` just completed. */
    public pull(resolve: (id: string) => Behaviour | undefined): void {
        for (const input of this.inputs.pins) {
            const source = resolve(input.link.target);
            if (!source)
                continue;
            const rate = this.inputRates[input.resource] ?? Decimal.dZero;
            const taken = source.take(input.link.resource, rate.mul(this.pendingCycles));
            this.give(input.resource, taken);
        }
    }

    public take(resource: Resource, amount: DecimalSource): Decimal {
        const available = this.storage[resource] ?? Decimal.dZero;
        const taken = available.min(amount);
        this.storage[resource] = available.sub(taken);
        return taken;
    }

    protected give(resource: Resource, amount: DecimalSource): void {
        this.storage[resource] = (this.storage[resource] ?? Decimal.dZero).add(amount);
    }

    public getStorage(): Partial<Resources> {
        return { ...this.storage };
    }

    public getDisplayInfo(): BehaviourDisplayInfo {
        const info = super.getDisplayInfo();
        info.storages['Буфер'] = { ...this.storage } as Resources;
        return {
            ...info,
            raw: {
                cycleTime: this.cycleTime,
                cycleLength: this.cycleLength,
                inputRates: this.inputRates,
                outputRates: this.outputRates,
            },
        } as any;
    }

    public reset() {
        for (const res of Object.keys(this.storage))
            delete (this.storage[res as Resource]);
    }
}

// export class Storage extends Behaviour {
//     public static type: string = 'storage';
// }

export const behaviours = {
    'converter': Converter,
    // 'storage': ,
} satisfies Record<string, { new(source: never): Behaviour }>;