import { isApiErrorV1 } from './simulation-contract.ts';

export type SimulationApiChoice = { id: string; label: string };

function scalar(value: unknown): string {
    return typeof value === 'string' ||
        (typeof value === 'number' && Number.isFinite(value))
        ? String(value)
        : '';
}

/** Parse API bodies without leaking JSON parser errors into the public form. */
export async function readSimulationApiJson(
    response: Response,
): Promise<unknown> {
    try {
        return await response.json();
    } catch {
        return null;
    }
}

/** Prefer field validation details, falling back to the shared API message. */
export function simulationApiErrorMessage(value: unknown): string | undefined {
    if (!isApiErrorV1(value)) return undefined;
    const validationMessages = Object.values(value.errors ?? {}).flat();
    return validationMessages.length
        ? validationMessages.join(' ')
        : value.message;
}

/** Keep snapshot field errors attached to their original form fields. */
export function simulationApiFieldErrors(
    value: unknown,
): Record<string, string> {
    if (!isApiErrorV1(value)) return {};
    const fields: Record<string, string> = {};
    for (const [path, messages] of Object.entries(value.errors ?? {})) {
        const key = path
            .replace(/^(economic_snapshot|personal_snapshot)\./, '')
            .split('.')[0];
        if (/^[a-z][a-z0-9_]*$/.test(key) && messages.length)
            fields[key] = messages.join(' ');
    }
    return fields;
}

/** Explain a failed status check without implying the accepted job was lost. */
export function simulationPollingFailureMessage(value: unknown): string {
    return (
        simulationApiErrorMessage(value) ??
        'O cenário foi recebido, mas não foi possível confirmar o estado do cálculo. Consulte o histórico antes de tentar novamente.'
    );
}

/** Validate and normalize the public reference catalog envelope. */
export function simulationCatalogChoices(
    value: unknown,
): SimulationApiChoice[] {
    if (
        !value ||
        typeof value !== 'object' ||
        Array.isArray(value) ||
        !Array.isArray((value as Record<string, unknown>).data)
    )
        throw new Error('O servidor devolveu opções com formato inválido.');

    return (value as { data: unknown[] }).data.flatMap((row) => {
        if (!row || typeof row !== 'object' || Array.isArray(row)) return [];
        const record = row as Record<string, unknown>;
        const choice = {
            id: scalar(record.id ?? record.value),
            label: scalar(record.label ?? record.name),
        };
        return choice.id && choice.label ? [choice] : [];
    });
}