import { and, desc, eq, inArray, like, or, sql } from "drizzle-orm";
import { drizzle } from "drizzle-orm/mysql2";
import {
  etablissements,
  InsertEtablissement,
  InsertMotCle,
  InsertPodcast,
  InsertUser,
  motsCles,
  podcastMotsCles,
  podcasts,
  users,
} from "../drizzle/schema";
import { ENV } from "./_core/env";

let _db: ReturnType<typeof drizzle> | null = null;

export async function getDb() {
  if (!_db && process.env.DATABASE_URL) {
    try {
      _db = drizzle(process.env.DATABASE_URL);
    } catch (error) {
      console.warn("[Database] Failed to connect:", error);
      _db = null;
    }
  }
  return _db;
}

// ─── Users ─────────────────────────────────────────────────────────────────────

export async function upsertUser(user: InsertUser): Promise<void> {
  if (!user.openId) throw new Error("User openId is required for upsert");
  const db = await getDb();
  if (!db) return;

  const values: InsertUser = { openId: user.openId };
  const updateSet: Record<string, unknown> = {};
  const textFields = ["name", "email", "loginMethod"] as const;

  textFields.forEach((field) => {
    const value = user[field];
    if (value === undefined) return;
    const normalized = value ?? null;
    values[field] = normalized;
    updateSet[field] = normalized;
  });

  if (user.lastSignedIn !== undefined) {
    values.lastSignedIn = user.lastSignedIn;
    updateSet.lastSignedIn = user.lastSignedIn;
  }
  if (user.role !== undefined) {
    values.role = user.role;
    updateSet.role = user.role;
  } else if (user.openId === ENV.ownerOpenId) {
    values.role = "admin";
    updateSet.role = "admin";
  }
  if (!values.lastSignedIn) values.lastSignedIn = new Date();
  if (Object.keys(updateSet).length === 0) updateSet.lastSignedIn = new Date();

  await db.insert(users).values(values).onDuplicateKeyUpdate({ set: updateSet });
}

export async function getUserByOpenId(openId: string) {
  const db = await getDb();
  if (!db) return undefined;
  const result = await db.select().from(users).where(eq(users.openId, openId)).limit(1);
  return result[0];
}

export async function getAllUsers() {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(users).orderBy(desc(users.createdAt));
}

export async function updateUserRole(userId: number, role: "user" | "admin") {
  const db = await getDb();
  if (!db) return;
  // Protect immutable accounts
  const target = await db.select().from(users).where(eq(users.id, userId)).limit(1);
  if (target[0]?.immutable) throw new Error("Ce compte est immuable et ne peut pas être modifié");
  await db.update(users).set({ role }).where(eq(users.id, userId));
}

export async function getUserByUsername(username: string) {
  const db = await getDb();
  if (!db) return undefined;
  const result = await db.select().from(users).where(eq(users.username, username)).limit(1);
  return result[0];
}

export async function createLocalUser(data: {
  username: string;
  passwordHash: string;
  name: string;
  role: "user" | "admin";
  immutable?: boolean;
  openId: string;
}) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  await db.insert(users).values({
    openId: data.openId,
    username: data.username,
    passwordHash: data.passwordHash,
    name: data.name,
    role: data.role,
    immutable: data.immutable ?? false,
    loginMethod: "local",
    lastSignedIn: new Date(),
  }).onDuplicateKeyUpdate({
    set: { name: data.name, role: data.role },
  });
}

export async function updateUser(
  id: number,
  data: { name?: string; username?: string; passwordHash?: string; role?: "user" | "admin" }
) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  const target = await db.select().from(users).where(eq(users.id, id)).limit(1);
  if (!target[0]) throw new Error("Utilisateur introuvable");
  if (target[0].immutable) throw new Error("Ce compte est immuable et ne peut pas être modifié");
  const updateData: Record<string, unknown> = {};
  if (data.name !== undefined) updateData.name = data.name;
  if (data.username !== undefined) updateData.username = data.username;
  if (data.passwordHash !== undefined) updateData.passwordHash = data.passwordHash;
  if (data.role !== undefined) updateData.role = data.role;
  if (Object.keys(updateData).length > 0) {
    await db.update(users).set(updateData).where(eq(users.id, id));
  }
}

export async function deleteUser(id: number) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  const target = await db.select().from(users).where(eq(users.id, id)).limit(1);
  if (!target[0]) throw new Error("Utilisateur introuvable");
  if (target[0].immutable) throw new Error("Ce compte est immuable et ne peut pas être supprimé");
  await db.delete(users).where(eq(users.id, id));
}

export async function getUserById(id: number) {
  const db = await getDb();
  if (!db) return undefined;
  const result = await db.select().from(users).where(eq(users.id, id)).limit(1);
  return result[0];
}

// ─── Établissements ────────────────────────────────────────────────────────────

export async function getAllEtablissements() {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(etablissements).orderBy(etablissements.nom);
}

export async function getEtablissementById(id: number) {
  const db = await getDb();
  if (!db) return undefined;
  const result = await db.select().from(etablissements).where(eq(etablissements.id, id)).limit(1);
  return result[0];
}

export async function createEtablissement(data: InsertEtablissement) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  const result = await db.insert(etablissements).values(data);
  return result[0];
}

export async function updateEtablissement(id: number, data: Partial<InsertEtablissement>) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  await db.update(etablissements).set(data).where(eq(etablissements.id, id));
}

export async function deleteEtablissement(id: number) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  await db.delete(etablissements).where(eq(etablissements.id, id));
}

// ─── Mots-clés ─────────────────────────────────────────────────────────────────

export async function getAllMotsCles() {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(motsCles).orderBy(motsCles.label);
}

export async function createMotCle(data: InsertMotCle) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  await db.insert(motsCles).values(data);
}

export async function deleteMotCle(id: number) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  await db.delete(motsCles).where(eq(motsCles.id, id));
}

// ─── Podcasts ──────────────────────────────────────────────────────────────────

export interface PodcastWithRelations {
  id: number;
  titre: string;
  resume: string;
  etablissementId: number;
  etablissementNom: string;
  audioUrl: string | null;
  audioKey: string | null;
  dureeSecondes: number | null;
  statut: "brouillon" | "publie";
  auteurId: number | null;
  auteurNom: string | null;
  imageUrl: string | null;
  createdAt: Date;
  updatedAt: Date;
  motsCles: { id: number; label: string }[];
}

export async function getPodcasts(opts?: {
  etablissementId?: number;
  motCleIds?: number[];
  search?: string;
  statut?: "brouillon" | "publie";
  auteurId?: number;
}): Promise<PodcastWithRelations[]> {
  const db = await getDb();
  if (!db) return [];

  const conditions = [];
  if (opts?.etablissementId) conditions.push(eq(podcasts.etablissementId, opts.etablissementId));
  if (opts?.statut) conditions.push(eq(podcasts.statut, opts.statut));
  if (opts?.auteurId) conditions.push(eq(podcasts.auteurId, opts.auteurId));
  if (opts?.search) {
    conditions.push(
      or(
        like(podcasts.titre, `%${opts.search}%`),
        like(podcasts.resume, `%${opts.search}%`)
      )
    );
  }

  const rows = await db
    .select({
      id: podcasts.id,
      titre: podcasts.titre,
      resume: podcasts.resume,
      etablissementId: podcasts.etablissementId,
      etablissementNom: etablissements.nom,
      audioUrl: podcasts.audioUrl,
      audioKey: podcasts.audioKey,
      dureeSecondes: podcasts.dureeSecondes,
      statut: podcasts.statut,
      auteurId: podcasts.auteurId,
      auteurNom: users.name,
      imageUrl: podcasts.imageUrl,
      createdAt: podcasts.createdAt,
      updatedAt: podcasts.updatedAt,
    })
    .from(podcasts)
    .leftJoin(etablissements, eq(podcasts.etablissementId, etablissements.id))
    .leftJoin(users, eq(podcasts.auteurId, users.id))
    .where(conditions.length > 0 ? and(...conditions) : undefined)
    .orderBy(desc(podcasts.createdAt));

  // Charger les mots-clés pour chaque podcast
  const podcastIds = rows.map((r) => r.id);
  let keywordsMap: Map<number, { id: number; label: string }[]> = new Map();

  if (podcastIds.length > 0) {
    const kwRows = await db
      .select({
        podcastId: podcastMotsCles.podcastId,
        motCleId: motsCles.id,
        label: motsCles.label,
      })
      .from(podcastMotsCles)
      .innerJoin(motsCles, eq(podcastMotsCles.motCleId, motsCles.id))
      .where(inArray(podcastMotsCles.podcastId, podcastIds));

    for (const kw of kwRows) {
      if (!keywordsMap.has(kw.podcastId)) keywordsMap.set(kw.podcastId, []);
      keywordsMap.get(kw.podcastId)!.push({ id: kw.motCleId, label: kw.label });
    }
  }

  let result = rows.map((r) => ({
    ...r,
    etablissementNom: r.etablissementNom ?? "",
    auteurNom: r.auteurNom ?? null,
    motsCles: keywordsMap.get(r.id) ?? [],
  }));

  // Filtrer par mots-clés si demandé
  if (opts?.motCleIds && opts.motCleIds.length > 0) {
    result = result.filter((p) =>
      opts.motCleIds!.some((id) => p.motsCles.some((mk) => mk.id === id))
    );
  }

  return result;
}

export async function getPodcastById(id: number): Promise<PodcastWithRelations | undefined> {
  const results = await getPodcasts();
  return results.find((p) => p.id === id);
}

export async function createPodcast(
  data: InsertPodcast,
  motCleIds: number[]
): Promise<number> {
  const db = await getDb();
  if (!db) throw new Error("DB not available");

  const result = await db.insert(podcasts).values(data);
  const insertId = (result[0] as any).insertId as number;

  if (motCleIds.length > 0) {
    await db.insert(podcastMotsCles).values(
      motCleIds.map((motCleId) => ({ podcastId: insertId, motCleId }))
    );
  }
  return insertId;
}

export async function updatePodcast(
  id: number,
  data: Partial<InsertPodcast>,
  motCleIds?: number[]
) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");

  await db.update(podcasts).set(data).where(eq(podcasts.id, id));

  if (motCleIds !== undefined) {
    await db.delete(podcastMotsCles).where(eq(podcastMotsCles.podcastId, id));
    if (motCleIds.length > 0) {
      await db.insert(podcastMotsCles).values(
        motCleIds.map((motCleId) => ({ podcastId: id, motCleId }))
      );
    }
  }
}

export async function deletePodcast(id: number) {
  const db = await getDb();
  if (!db) throw new Error("DB not available");
  await db.delete(podcasts).where(eq(podcasts.id, id));
}

export async function getPodcastStats() {
  const db = await getDb();
  if (!db) return { total: 0, publies: 0, brouillons: 0, etablissements: 0 };

  const [totalRow] = await db.select({ count: sql<number>`count(*)` }).from(podcasts);
  const [publiesRow] = await db
    .select({ count: sql<number>`count(*)` })
    .from(podcasts)
    .where(eq(podcasts.statut, "publie"));
  const [etabRow] = await db.select({ count: sql<number>`count(*)` }).from(etablissements);

  const total = Number(totalRow?.count ?? 0);
  const publies = Number(publiesRow?.count ?? 0);
  return {
    total,
    publies,
    brouillons: total - publies,
    etablissements: Number(etabRow?.count ?? 0),
  };
}