/**
 * Moteur de lecture RSS
 * Récupère les flux actifs, parse les articles, applique les règles d'automatisme,
 * et insère les nouveaux articles dans veille_items ou aap_items.
 */
import { XMLParser } from "fast-xml-parser";
import * as crypto from "crypto";
import { getDb } from "./db";
import {
  rssFeeds,
  veilleItems,
  aapItems,
  type RssFeed,
} from "../drizzle/schema";
import { eq } from "drizzle-orm";

// ─── Types internes ───────────────────────────────────────────────────────────

interface RssItem {
  title: string;
  description?: string;
  link?: string;
  pubDate?: string;
  guid?: string;
}

interface AutoRule {
  keyword: string;
  typeVeille?: "reglementaire" | "concurrentielle" | "technologique" | "generale";
  categorieAap?: "Handicap" | "PA" | "Enfance" | "Précarité" | "Sanitaire" | "Autre";
}

interface FetchResult {
  feedId: number;
  feedName: string;
  status: "ok" | "error";
  newItems: number;
  skippedItems: number;
  error?: string;
}

// ─── Utilitaires ─────────────────────────────────────────────────────────────

function dedupHash(text: string): string {
  return crypto.createHash("sha256").update(text).digest("hex").substring(0, 64);
}

function parseDate(dateStr?: string): Date | null {
  if (!dateStr) return null;
  const d = new Date(dateStr);
  return isNaN(d.getTime()) ? null : d;
}

function stripHtml(html: string): string {
  return html.replace(/<[^>]*>/g, "").replace(/&amp;/g, "&").replace(/&lt;/g, "<").replace(/&gt;/g, ">").replace(/&quot;/g, '"').replace(/&#39;/g, "'").trim();
}

/**
 * Applique les règles d'automatisme sur le titre + description d'un article.
 * Retourne le premier match trouvé, ou null si aucune règle ne correspond.
 */
function applyAutoRules(
  title: string,
  description: string,
  rules: AutoRule[]
): AutoRule | null {
  const text = (title + " " + description).toLowerCase();
  for (const rule of rules) {
    if (text.includes(rule.keyword.toLowerCase())) {
      return rule;
    }
  }
  return null;
}

// ─── Parsing RSS/Atom ─────────────────────────────────────────────────────────

async function fetchAndParseRss(url: string): Promise<RssItem[]> {
  const response = await fetch(url, {
    headers: {
      "User-Agent": "Mozilla/5.0 (compatible; VeilleBot/1.0; +https://itinova.fr)",
      "Accept": "application/rss+xml, application/xml, text/xml, */*",
    },
    signal: AbortSignal.timeout(15000),
  });

  if (!response.ok) {
    throw new Error(`HTTP ${response.status} ${response.statusText}`);
  }

  const xml = await response.text();
  const parser = new XMLParser({
    ignoreAttributes: false,
    attributeNamePrefix: "@_",
    textNodeName: "#text",
    parseAttributeValue: true,
    trimValues: true,
  });

  const parsed = parser.parse(xml);

  // Support RSS 2.0
  const channel = parsed?.rss?.channel;
  if (channel) {
    const items = Array.isArray(channel.item) ? channel.item : channel.item ? [channel.item] : [];
    return items.map((item: any) => ({
      title: String(item.title?.["#text"] ?? item.title ?? ""),
      description: String(item.description?.["#text"] ?? item.description ?? ""),
      link: String(item.link?.["#text"] ?? item.link ?? item.guid?.["#text"] ?? item.guid ?? ""),
      pubDate: String(item.pubDate ?? item["dc:date"] ?? ""),
      guid: String(item.guid?.["#text"] ?? item.guid ?? item.link ?? ""),
    }));
  }

  // Support Atom
  const feed = parsed?.feed;
  if (feed) {
    const entries = Array.isArray(feed.entry) ? feed.entry : feed.entry ? [feed.entry] : [];
    return entries.map((entry: any) => {
      const links = Array.isArray(entry.link) ? entry.link : entry.link ? [entry.link] : [];
      const altLink = links.find((l: any) => l["@_rel"] === "alternate") ?? links[0];
      return {
        title: String(entry.title?.["#text"] ?? entry.title ?? ""),
        description: String(entry.summary?.["#text"] ?? entry.summary ?? entry.content?.["#text"] ?? ""),
        link: String(altLink?.["@_href"] ?? ""),
        pubDate: String(entry.published ?? entry.updated ?? ""),
        guid: String(entry.id ?? altLink?.["@_href"] ?? ""),
      };
    });
  }

  throw new Error("Format RSS/Atom non reconnu");
}

// ─── Traitement d'un flux ─────────────────────────────────────────────────────

async function processFeed(feed: RssFeed): Promise<FetchResult> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");

  const result: FetchResult = {
    feedId: feed.id,
    feedName: feed.name,
    status: "ok",
    newItems: 0,
    skippedItems: 0,
  };

  try {
    const items = await fetchAndParseRss(feed.url);
    const rules: AutoRule[] = Array.isArray(feed.autoRules) ? feed.autoRules as AutoRule[] : [];

    for (const item of items) {
      const title = stripHtml(item.title || "");
      const description = stripHtml(item.description || "");
      const link = item.link || item.guid || "";
      const pubDate = parseDate(item.pubDate);

      if (!title) {
        result.skippedItems++;
        continue;
      }

      // Clé de déduplication basée sur le titre + lien
      const dedupKey = dedupHash(title + "|" + link);

      if (feed.feedType === "veille") {
        // Déterminer le type de veille
        const matchedRule = applyAutoRules(title, description, rules);
        const typeVeille = (matchedRule?.typeVeille ?? feed.defaultTypeVeille ?? "generale") as
          "reglementaire" | "concurrentielle" | "technologique" | "generale";

        try {
          await db.insert(veilleItems).values({
            dedupKey,
            titre: title,
            resume: description || null,
            source: feed.name,
            lien: link || null,
            typeVeille,
            datePublication: pubDate,
          });
          result.newItems++;
        } catch (e: any) {
          // Doublon (contrainte UNIQUE sur dedupKey) → on ignore
          if (e?.code === "ER_DUP_ENTRY" || e?.message?.includes("Duplicate entry")) {
            result.skippedItems++;
          } else {
            throw e;
          }
        }
      } else if (feed.feedType === "aap") {
        // Déterminer la catégorie AAP
        const matchedRule = applyAutoRules(title, description, rules);
        const categorie = (matchedRule?.categorieAap ?? feed.defaultCategorieAap ?? "Autre") as
          "Handicap" | "PA" | "Enfance" | "Précarité" | "Sanitaire" | "Autre";

        try {
          await db.insert(aapItems).values({
            dedupKey,
            titre: title,
            categorie,
            lien: link || null,
            datePublication: pubDate,
          });
          result.newItems++;
        } catch (e: any) {
          if (e?.code === "ER_DUP_ENTRY" || e?.message?.includes("Duplicate entry")) {
            result.skippedItems++;
          } else {
            throw e;
          }
        }
      }
    }

    // Mettre à jour lastFetchedAt et lastFetchStatus
    await db.update(rssFeeds)
      .set({ lastFetchedAt: new Date(), lastFetchStatus: "ok", lastFetchError: null })
      .where(eq(rssFeeds.id, feed.id));

  } catch (e: any) {
    result.status = "error";
    result.error = e?.message ?? String(e);
    // Enregistrer l'erreur dans le flux
    try {
      await db.update(rssFeeds)
        .set({ lastFetchedAt: new Date(), lastFetchStatus: "error", lastFetchError: result.error })
        .where(eq(rssFeeds.id, feed.id));
    } catch (_) { /* ignore */ }
  }

  return result;
}

// ─── Point d'entrée principal ─────────────────────────────────────────────────

export interface RssFetchSummary {
  totalFeeds: number;
  successFeeds: number;
  errorFeeds: number;
  totalNewItems: number;
  totalSkippedItems: number;
  results: FetchResult[];
  executedAt: string;
}

export async function runRssFetch(): Promise<RssFetchSummary> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");

  // Récupérer tous les flux actifs
  const feeds = await db.select().from(rssFeeds).where(eq(rssFeeds.isActive, true));

  const results: FetchResult[] = [];

  for (const feed of feeds) {
    console.log(`[RSS] Lecture du flux: ${feed.name} (${feed.url})`);
    const result = await processFeed(feed);
    results.push(result);
    console.log(`[RSS] ${feed.name}: ${result.newItems} nouveaux, ${result.skippedItems} doublons, statut: ${result.status}`);
  }

  const summary: RssFetchSummary = {
    totalFeeds: feeds.length,
    successFeeds: results.filter(r => r.status === "ok").length,
    errorFeeds: results.filter(r => r.status === "error").length,
    totalNewItems: results.reduce((acc, r) => acc + r.newItems, 0),
    totalSkippedItems: results.reduce((acc, r) => acc + r.skippedItems, 0),
    results,
    executedAt: new Date().toISOString(),
  };

  console.log(`[RSS] Terminé: ${summary.totalNewItems} nouveaux articles, ${summary.errorFeeds} erreurs`);
  return summary;
}