import {
    isMonolithLogOrigin,
    MAX_JOURNEY_CORRELATED_REQUESTS,
    sanitizeRequestCorrelation,
} from '../core/request-correlation';
import type { JourneyEvent, JourneyRequestEvent } from '../core/types';

const DISCOVER_URL = 'https://kibana.st.dev/app/discover#/';
// Production monolith logs; deliberately not the user's default data view.
const DATA_VIEW_ID = '894110ed-c22d-449c-9dc2-c4816f08712a';
const WINDOW_PADDING_MS = 60_000;

/** Fixed destination and validated Ray ID only — no request URL, query string or user data. */
export function requestLogsUrl(value: JourneyRequestEvent): string | undefined {
    const request = sanitizeRequestCorrelation(value);
    if (!request) {
        return undefined;
    }
    const from = new Date(request.startedAtEpoch - WINDOW_PADDING_MS).toISOString();
    const to = new Date(
        request.startedAtEpoch + request.durationMs + WINDOW_PADDING_MS
    ).toISOString();
    // Origin/edge datacenter suffixes can differ. Match the hex prefix within the request window.
    const rayPrefix = request.rayId.slice(0, 16);
    return discoverUrl(`Request.RequestId: ${rayPrefix}*`, from, to);
}

interface JourneyLogLink {
    url: string;
    scope: 'request' | 'related_requests' | 'related_logs';
}

function discoverUrl(query: string, from: string, to: string): string {
    const globalState = `(refreshInterval:(pause:!t,value:0),time:(from:'${from}',to:'${to}'))`;
    // The query is a quoted Rison string containing a separately escaped KQL expression.
    const quotedQuery = query.replace(/!/g, '!!').replace(/'/g, "!'");
    const appState = `(dataSource:(type:dataView,dataViewId:'${DATA_VIEW_ID}'),query:(language:kuery,query:'${quotedQuery}'))`;
    return `${DISCOVER_URL}?_g=${encodeURIComponent(globalState)}&_a=${encodeURIComponent(appState)}`;
}

function userValue(value: unknown): string | undefined {
    return typeof value === 'string' &&
        value.length > 0 &&
        value.length <= 254 &&
        // eslint-disable-next-line no-control-regex -- Reject controls in log query values.
        !/[\u0000-\u001f\u007f]/.test(value)
        ? value
        : undefined;
}

function kqlValue(value: string): string {
    return `"${value.replace(/\\/g, '\\\\').replace(/"/g, '\\"')}"`;
}

function relatedLogsUrl(
    durationMs: number,
    user: unknown,
    pageUrl: string | undefined
): string | undefined {
    if (
        !pageUrl ||
        !isMonolithLogOrigin(pageUrl) ||
        !user ||
        typeof user !== 'object' ||
        !Number.isFinite(durationMs) ||
        durationMs < 0 ||
        durationMs > 86_400_000
    ) {
        return;
    }
    const context = user as Record<string, unknown>;
    const tenant = userValue(context.tenant);
    const users = [...new Set([userValue(context.name), userValue(context.email)])].filter(
        (value): value is string => value !== undefined
    );
    // Never fall back to all tenants or all users when identity is missing.
    if (!tenant || !/^[a-z0-9][a-z0-9_-]*$/i.test(tenant) || users.length === 0) {
        return;
    }
    const query = `Context.TenantName: ${kqlValue(tenant)} AND (${users
        .map(value => `Request.User: ${kqlValue(value)}`)
        .join(' OR ')})`;
    const now = Date.now();
    return discoverUrl(
        query,
        new Date(now - durationMs - WINDOW_PADDING_MS).toISOString(),
        new Date(now + WINDOW_PADDING_MS).toISOString()
    );
}

/** Keep one visible link without claiming unrelated requests caused a JS/business failure. */
export function journeyLogsLink(
    journey: JourneyEvent['journey'],
    getUser?: () => unknown,
    pageUrl?: string
): JourneyLogLink | undefined {
    if (journey.failedRequest) {
        const url = requestLogsUrl(journey.failedRequest);
        if (url) {
            return { url, scope: 'request' };
        }
    }

    /*
     * With no identified failure request, search this user's logs during the journey.
     * RUM stubs/older hosts can lack getUser; enrichment must never prevent emission.
     */
    try {
        const url = relatedLogsUrl(journey.durationMs, getUser?.(), pageUrl);
        if (url) {
            return { url, scope: 'related_logs' };
        }
    } catch {
        // Retain request-only links if session context is unavailable or malformed.
    }

    const requests = journey.steps
        .flatMap(step => step.requests ?? [])
        .slice(0, MAX_JOURNEY_CORRELATED_REQUESTS)
        .map(sanitizeRequestCorrelation)
        .filter((request): request is JourneyRequestEvent => request !== undefined);
    if (!requests.length) {
        return;
    }
    const prefixes = [...new Set(requests.map(request => request.rayId.slice(0, 16)))];
    const query = prefixes.map(prefix => `Request.RequestId: ${prefix}*`).join(' OR ');
    return {
        url: discoverUrl(
            query,
            new Date(
                Math.min(...requests.map(request => request.startedAtEpoch)) - WINDOW_PADDING_MS
            ).toISOString(),
            new Date(
                Math.max(...requests.map(request => request.startedAtEpoch + request.durationMs)) +
                    WINDOW_PADDING_MS
            ).toISOString()
        ),
        scope: 'related_requests',
    };
}