import type { AcceptMsaRequest } from '../services/BAAService';
import type { MsaPreview } from './msaAgreement';

export type HeldMsaOperation = { organizationId: string; actorId: string; request: AcceptMsaRequest; preview: MsaPreview };
export const msaObject = (value: unknown): value is Record<string, unknown> => typeof value === 'object' && value !== null;
const text = (value: unknown): value is string => typeof value === 'string' && value.trim().length > 0;
export const msaOperationId = (value: unknown): value is string => typeof value === 'string' && /^[a-f0-9]{8}(-[a-f0-9]{4}){3}-[a-f0-9]{12}$/.test(value);
const runs = (value: unknown): boolean => value === undefined || (Array.isArray(value) && value.every((run: unknown) =>
    msaObject(run) && typeof run.text === 'string' && (run.bold === undefined || run.bold === true)
    && (run.italic === undefined || run.italic === true) && (run.href === undefined || typeof run.href === 'string')));
const block = (value: unknown): boolean => {
    if (!msaObject(value)) return false;
    if (value.type === 'list') return Array.isArray(value.items) && value.items.every((item: unknown) => typeof item === 'string')
        && (value.ordered === undefined || value.ordered === true)
        && (value.itemRuns === undefined || (Array.isArray(value.itemRuns) && value.itemRuns.every(runs)));
    return (value.type === 'title' || value.type === 'heading' || value.type === 'paragraph')
        && typeof value.text === 'string' && runs(value.runs);
};

export const isMsaRequest = (value: unknown): value is AcceptMsaRequest => msaObject(value) && msaOperationId(value.operationId)
    && [value.signerName, value.signerTitle, value.documentVersion, value.editionHash, value.signDate, value.factsDigest].every(text)
    && msaObject(value.signingAttestation) && text(value.signingAttestation.statementVersion);

export const sameMsaRequest = (a: AcceptMsaRequest, b: AcceptMsaRequest): boolean =>
    a.operationId === b.operationId && a.signerName === b.signerName && a.signerTitle === b.signerTitle
    && a.documentVersion === b.documentVersion && a.editionHash === b.editionHash && a.signDate === b.signDate
    && a.factsDigest === b.factsDigest && a.signingAttestation.statementVersion === b.signingAttestation.statementVersion;

export const isMsaPreview = (value: unknown): value is MsaPreview => {
    if (!msaObject(value) || !msaObject(value.facts)) return false;
    const facts = value.facts;
    return [value.version, value.editionHash, value.title, value.signDate, value.factsDigest].every(text)
        && Array.isArray(value.blocks) && value.blocks.every(block)
        && ['orgName', 'orgAddress', 'orgPhone'].every((key) => typeof facts[key] === 'string');
};

export const msaPreviewMatches = (preview: MsaPreview, request: AcceptMsaRequest): boolean =>
    preview.version === request.documentVersion && preview.editionHash === request.editionHash
    && preview.signDate === request.signDate && preview.factsDigest === request.factsDigest;

export const heldMsaKey = (organizationId: string, actorId: string): string => 'akashic.msa.operation.' + organizationId + '.' + actorId;
export const heldMsaRecordKey = (organizationId: string, actorId: string, operationId: string): string => heldMsaKey(organizationId, actorId) + '.op.' + operationId;

const decodeHeld = (raw: string, organizationId: string, actorId: string): HeldMsaOperation | 'unavailable' => {
    const value: unknown = JSON.parse(raw);
    return msaObject(value) && value.organizationId === organizationId && value.actorId === actorId
        && isMsaRequest(value.request) && isMsaPreview(value.preview) && msaPreviewMatches(value.preview, value.request)
        ? { organizationId, actorId, request: value.request, preview: value.preview } : 'unavailable';
};

export const readHeldMsa = (organizationId: string, actorId: string): HeldMsaOperation | 'unavailable' | undefined => {
    try {
        const raw = window.localStorage.getItem(heldMsaKey(organizationId, actorId));
        if (raw) return decodeHeld(raw, organizationId, actorId);
        // Each act keeps its own record: a concurrent pointer clear cannot lose another window's reference.
        const prefix = heldMsaKey(organizationId, actorId) + '.op.';
        const keys: string[] = [];
        for (let i = 0; i < window.localStorage.length; i += 1) {
            const key = window.localStorage.key(i);
            if (key?.startsWith(prefix)) keys.push(key);
        }
        for (const key of keys.sort()) {
            const retained = window.localStorage.getItem(key);
            if (retained) return decodeHeld(retained, organizationId, actorId);
        }
        return window.localStorage.getItem('akashic.msa.operation.' + organizationId) ? 'unavailable' : undefined;
    } catch { return 'unavailable'; }
};

/** Only the original holder may be replaced or cleared; a late A never removes B's reference. */
export const writeHeldMsa = (organizationId: string, actorId: string, held: HeldMsaOperation | undefined, expectedOperationId?: string): boolean => {
    const key = heldMsaKey(organizationId, actorId);
    const current = readHeldMsa(organizationId, actorId);
    if (current === 'unavailable') throw new Error('The recovery reference could not be read.');
    if (current && current.request.operationId !== (held?.request.operationId ?? expectedOperationId)) return false;
    if (current && held && !sameMsaRequest(current.request, held.request)) return false;
    if (held) {
        const encoded = JSON.stringify(held);
        const recordKey = heldMsaRecordKey(organizationId, actorId, held.request.operationId);
        window.localStorage.setItem(recordKey, encoded);
        if (window.localStorage.getItem(recordKey) !== encoded) throw new Error('The recovery reference could not be saved.');
        window.localStorage.setItem(key, encoded);
        if (window.localStorage.getItem(key) !== encoded) throw new Error('The recovery reference could not be saved.');
    } else if (current) {
        window.localStorage.removeItem(heldMsaRecordKey(organizationId, actorId, current.request.operationId));
        window.localStorage.removeItem(key);
    }
    return true;
};