import type { DeskAnswer } from './desk-field-values';

export type DeskAnswers = Record<string, DeskAnswer>;
export type CheckpointRequest = {
    id: string;
    version: number;
    status: string;
    payload: DeskAnswers;
    editable_fields: string[];
    can_edit: boolean;
    protocol: string | null;
    analyst_id: number | null;
    due_at: string | null;
};
export type CheckpointInput = {
    version: number;
    request_version: number;
    operation_key: string;
    payload: DeskAnswers;
    edited_keys: string[];
    reason: string;
};
export type DeskCheckpoint = {
    version: number;
    request_version: number;
    updated_at: string;
    payload: DeskAnswers;
    base_payload: DeskAnswers;
    edited_keys: string[];
    reason: string;
};
export type CheckpointView = {
    installed: boolean;
    request: CheckpointRequest;
    checkpoint: DeskCheckpoint | null;
};
export type RecoveryChoice = 'page' | 'saved' | 'current';

export function checkpointSignature(values: DeskAnswers): string {
    return JSON.stringify(
        Object.fromEntries(
            Object.entries(values)
                .sort(([a], [b]) => a.localeCompare(b))
                .map(([key, value]) => [
                    key,
                    Array.isArray(value) ? [...value].sort() : (value ?? null),
                ]),
        ),
    );
}
export const checkpointSame = (
    a: DeskAnswer | undefined,
    b: DeskAnswer | undefined,
) =>
    checkpointSignature({ value: a ?? null }) ===
    checkpointSignature({ value: b ?? null });

const contextKeys = [
    'context_opportunity',
    'context_opportunity_snapshot',
    'context_reuse',
];
function contextLabel(values: DeskAnswers | undefined): string {
    if (!values?.context_opportunity) return 'Sem oportunidade seleccionada';
    try {
        const snapshot = JSON.parse(
            String(values.context_opportunity_snapshot ?? '{}'),
        );
        if (typeof snapshot.choice?.opportunity?.title === 'string')
            return (
                snapshot.choice.opportunity.title +
                (Number.isInteger(snapshot.revision)
                    ? ` · revisão ${snapshot.revision}`
                    : '')
            );
    } catch {
        /* A legacy context still remains recoverable. */
    }
    return 'Oportunidade seleccionada; designação por recuperar';
}

/** Three sources remain explicit; a deliberate revert is still an edit. */
export function checkpointRecovery(
    base: DeskAnswers,
    page: DeskAnswers,
    edited: readonly string[],
    current: DeskAnswers,
    saved: DeskCheckpoint | null,
    allowed: readonly string[],
    choices: Record<string, RecoveryChoice> = {},
) {
    const payload = { ...current };
    const conflicts: string[] = [];
    const intent: string[] = [];
    const rows: {
        key: string;
        page: DeskAnswer | null;
        saved: DeskAnswer | null;
        current: DeskAnswer | null;
        conflict: boolean;
        choice: RecoveryChoice;
    }[] = [];
    for (const key of allowed) {
        if (contextKeys.includes(key) && key !== 'context_opportunity')
            continue;
        const group =
            key === 'context_opportunity'
                ? contextKeys.filter((k) => allowed.includes(k))
                : [key];
        const same = (a: DeskAnswers | undefined, b: DeskAnswers | undefined) =>
            group.every((k) => checkpointSame(a?.[k], b?.[k]));
        const local =
            group.some((k) => edited.includes(k)) || !same(page, base);
        const remote =
            !!saved &&
            (group.some((k) => saved.edited_keys.includes(k)) ||
                !same(saved.payload, saved.base_payload));
        if (!local && !remote) continue;
        const conflict =
            (local && remote && !same(page, saved?.payload)) ||
            (local && !same(base, current) && !same(page, current)) ||
            (remote &&
                !same(saved?.base_payload, current) &&
                !same(saved?.payload, current));
        const choice = choices[key] ?? (local ? 'page' : 'saved');
        if (conflict && !choices[key]) conflicts.push(key);
        for (const member of group)
            payload[member] =
                (choice === 'page'
                    ? page[member]
                    : choice === 'saved'
                      ? saved?.payload[member]
                      : current[member]) ?? null;
        if (choice !== 'current') intent.push(...group);
        rows.push({
            key,
            page:
                key === 'context_opportunity'
                    ? contextLabel(page)
                    : (page[key] ?? null),
            saved:
                key === 'context_opportunity'
                    ? contextLabel(saved?.payload)
                    : (saved?.payload[key] ?? null),
            current:
                key === 'context_opportunity'
                    ? contextLabel(current)
                    : (current[key] ?? null),
            conflict,
            choice,
        });
    }
    return { payload, conflicts, intent, rows };
}