import { PROTOCOL_VERSION } from './contract.js';
import type { IncomingMessage, OutgoingMessage } from './messages.js';

const INCOMING_TYPES = new Set<IncomingMessage['type']>([
    'hello_ack',
    'trainer_meta',
    'trainer_values',
    'game_status',
    'installed_apps',
    'value_changed',
    'trainer_changed',
    'set_value_result',
    'remote_command_result',
    'error',
]);

const OUTGOING_TYPES = new Set<OutgoingMessage['type']>(['hello', 'set_value', 'remote_command']);

export function isRecord(value: unknown): value is Record<string, unknown> {
    return typeof value === 'object' && value !== null;
}

export function isIncomingMessage(value: unknown): value is IncomingMessage {
    if (!isEnvelope(value) || !INCOMING_TYPES.has(value.type as IncomingMessage['type'])) {
        return false;
    }

    const payload = value.payload;
    switch (value.type) {
        case 'hello_ack':
            return (
                hasString(payload, 'sessionId') &&
                hasBoolean(payload, 'accepted') &&
                hasString(payload, 'serverVersion') &&
                hasNumber(payload, 'protocolVersion')
            );
        case 'trainer_meta':
            return (
                isRecord(payload.session) &&
                hasString(payload.session, 'instanceId') &&
                isRecord(payload.trainer) &&
                hasString(payload.trainer, 'trainerId') &&
                isRecord(payload.schema) &&
                Array.isArray(payload.schema.categories) &&
                Array.isArray(payload.schema.cheats)
            );
        case 'trainer_values':
            return hasString(payload, 'trainerId') && isRecord(payload.values);
        case 'installed_apps':
            return (
                hasString(payload, 'instanceId') &&
                hasString(payload, 'updatedAt') &&
                Array.isArray(payload.apps)
            );
        case 'game_status':
            return (
                hasString(payload, 'instanceId') &&
                hasString(payload, 'updatedAt') &&
                isRecord(payload.session) &&
                isRecord(payload.trainer)
            );
        case 'value_changed':
            return (
                hasString(payload, 'trainerId') &&
                hasString(payload, 'target') &&
                'value' in payload
            );
        case 'trainer_changed':
            return hasString(payload, 'trainerId');
        case 'set_value_result':
            return (
                hasBoolean(payload, 'ok') &&
                hasString(payload, 'trainerId') &&
                hasString(payload, 'target')
            );
        case 'remote_command_result':
            return (
                hasBoolean(payload, 'ok') &&
                (payload.action === 'launch' || payload.action === 'stop')
            );
        case 'error':
            return hasString(payload, 'code') && hasString(payload, 'message');
        default:
            return false;
    }
}

export function isOutgoingMessage(value: unknown): value is OutgoingMessage {
    if (!isEnvelope(value) || !OUTGOING_TYPES.has(value.type as OutgoingMessage['type'])) {
        return false;
    }

    const payload = value.payload;
    if (value.type === 'hello') {
        return (
            payload.client === 'mobile-web' &&
            hasString(payload, 'clientVersion') &&
            isRecord(payload.capabilities)
        );
    }
    if (value.type === 'set_value') {
        return (
            hasString(payload, 'trainerId') && hasString(payload, 'target') && 'value' in payload
        );
    }
    return payload.action === 'launch' || payload.action === 'stop';
}

function isEnvelope(value: unknown): value is Record<string, unknown> & {
    type: string;
    version: number;
    requestId: string | null;
    payload: Record<string, unknown>;
} {
    return (
        isRecord(value) &&
        typeof value.type === 'string' &&
        value.version === PROTOCOL_VERSION &&
        (value.requestId === null || typeof value.requestId === 'string') &&
        isRecord(value.payload)
    );
}

function hasString(value: Record<string, unknown>, key: string): boolean {
    return typeof value[key] === 'string';
}

function hasNumber(value: Record<string, unknown>, key: string): boolean {
    return typeof value[key] === 'number';
}

function hasBoolean(value: Record<string, unknown>, key: string): boolean {
    return typeof value[key] === 'boolean';
}