"use client";

import React, { useEffect, createContext, useContext } from "react";

// ── TYPES & INTERFACES ────────────────────────────────────────────────────────

export interface UTMParams {
  utm_source: string | null;
  utm_medium: string | null;
  utm_campaign: string | null;
  utm_content: string | null;
  utm_term: string | null;
  referrer: string | null;
}

export interface IdentifyTraits {
  userId: string | number;
  email: string;
  name?: string;
  plan?: string;
  [key: string]: any;
}

export interface VibnTrackerContextType {
  getStoredAttribution: () => UTMParams;
  clearAttribution: () => void;
  identify: (traits: IdentifyTraits) => void;
  track: (eventName: string, properties?: Record<string, any>) => void;
}

declare global {
  interface Window {
    umami?: {
      identify: (traits: Record<string, any>) => void;
      track: (eventName: string, properties?: Record<string, any>) => void;
    };
  }
}

// ── UTILITY FUNCTIONS ─────────────────────────────────────────────────────────

const COOKIE_EXPIRY_DAYS = 30;

function setCookie(name: string, value: string, days: number) {
  if (typeof document === "undefined") return;
  const date = new Date();
  date.setTime(date.getTime() + days * 24 * 60 * 60 * 1000);
  const expires = "; expires=" + date.toUTCString();
  document.cookie = name + "=" + (value || "") + expires + "; path=/; SameSite=Lax";
}

function getCookie(name: string): string | null {
  if (typeof document === "undefined") return null;
  const nameEQ = name + "=";
  const ca = document.cookie.split(";");
  for (let i = 0; i < ca.length; i++) {
    let c = ca[i];
    while (c.charAt(0) === " ") c = c.substring(1, c.length);
    if (c.indexOf(nameEQ) === 0) return c.substring(nameEQ.length, c.length);
  }
  return null;
}

function deleteCookie(name: string) {
  if (typeof document === "undefined") return;
  document.cookie = name + "=; Path=/; Expires=Thu, 01 Jan 1970 00:00:01 GMT;";
}

// ── CONTEXT PROVIDER ──────────────────────────────────────────────────────────

const VibnTrackerContext = createContext<VibnTrackerContextType | undefined>(undefined);

export function VibnTrackerProvider({
  children,
  umamiWebsiteId,
  umamiScriptUrl = "https://analytics.vibnai.com/script.js",
}: {
  children: React.ReactNode;
  umamiWebsiteId?: string;
  umamiScriptUrl?: string;
}) {
  useEffect(() => {
    if (typeof window === "undefined") return;

    // 1. Extract UTMs from active search string
    const urlParams = new URLSearchParams(window.location.search);
    const keys: Array<keyof UTMParams> = [
      "utm_source",
      "utm_medium",
      "utm_campaign",
      "utm_content",
      "utm_term",
    ];

    keys.forEach((key) => {
      const val = urlParams.get(key);
      if (val) {
        // Persist to sessionStorage (for current window lifespans)
        sessionStorage.setItem(key, val);
        // Persist to cookie (cross-session backup, used if user closes window and signs up later)
        setCookie(`vibn_${key}`, val, COOKIE_EXPIRY_DAYS);
      }
    });

    // 2. Persist browser referrer
    if (!sessionStorage.getItem("referrer") && !getCookie("vibn_referrer")) {
      const ref = document.referrer || "direct";
      sessionStorage.setItem("referrer", ref);
      setCookie("vibn_referrer", ref, COOKIE_EXPIRY_DAYS);
    }

    // 3. Inject Umami analytics script automatically if website ID provided
    if (umamiWebsiteId && !document.querySelector(`script[data-website-id="${umamiWebsiteId}"]`)) {
      const script = document.createElement("script");
      script.src = umamiScriptUrl;
      script.setAttribute("data-website-id", umamiWebsiteId);
      script.async = true;
      script.defer = true;
      document.head.appendChild(script);
    }
  }, [umamiWebsiteId, umamiScriptUrl]);

  const getStoredAttribution = (): UTMParams => {
    if (typeof window === "undefined") {
      return {
        utm_source: null,
        utm_medium: null,
        utm_campaign: null,
        utm_content: null,
        utm_term: null,
        referrer: null,
      };
    }

    return {
      utm_source: sessionStorage.getItem("utm_source") || getCookie("vibn_utm_source"),
      utm_medium: sessionStorage.getItem("utm_medium") || getCookie("vibn_utm_medium"),
      utm_campaign: sessionStorage.getItem("utm_campaign") || getCookie("vibn_utm_campaign"),
      utm_content: sessionStorage.getItem("utm_content") || getCookie("vibn_utm_content"),
      utm_term: sessionStorage.getItem("utm_term") || getCookie("vibn_utm_term"),
      referrer: sessionStorage.getItem("referrer") || getCookie("vibn_referrer"),
    };
  };

  const clearAttribution = () => {
    if (typeof window === "undefined") return;
    const keys = ["utm_source", "utm_medium", "utm_campaign", "utm_content", "utm_term", "referrer"];
    keys.forEach((key) => {
      sessionStorage.removeItem(key);
      deleteCookie(`vibn_${key}`);
    });
  };

  const identify = (traits: IdentifyTraits) => {
    if (typeof window !== "undefined" && window.umami) {
      window.umami.identify(traits);
      console.log(`[VibnTracker] User identified in Umami: ${traits.email}`);
    }
  };

  const track = (eventName: string, properties?: Record<string, any>) => {
    if (typeof window !== "undefined" && window.umami) {
      window.umami.track(eventName, properties);
      console.log(`[VibnTracker] Event tracked: "${eventName}"`, properties || "");
    }
  };

  return (
    <VibnTrackerContext.Provider
      value={{ getStoredAttribution, clearAttribution, identify, track }}
    >
      {children}
    </VibnTrackerContext.Provider>
  );
}

// ── CUSTOM HOOK ───────────────────────────────────────────────────────────────

export function useVibnTracker() {
  const context = useContext(VibnTrackerContext);
  if (!context) {
    throw new Error("useVibnTracker must be used within a VibnTrackerProvider");
  }
  return context;
}