import { eq, and, desc, sql } from "drizzle-orm";
import { drizzle } from "drizzle-orm/mysql2";
import { 
  InsertUser, 
  users, 
  sourceFiles,
  InsertSourceFile,
  SourceFile,
  invoices,
  InsertInvoice,
  Invoice,
  userSettings,
  InsertUserSettings,
  UserSettings,
  importLogs,
  InsertImportLog,
  ImportLog,
  llmLogs,
  InsertLlmLog,
  LlmLog,
  importSettings,
  InsertImportSettings,
  ImportSettings,
  departmentList,
  InsertDepartment,
  Department,
  accountingAllocationList,
  InsertAccountingAllocation,
  AccountingAllocation,
  automationRules,
  InsertAutomationRule,
  AutomationRule
} 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;
}

// ============= USER OPERATIONS =============

export async function upsertUser(user: InsertUser): Promise<void> {
  const db = await getDb();
  if (!db) {
    console.warn("[Database] Cannot upsert user: database not available");
    return;
  }

  try {
    const values: InsertUser = {
      email: user.email,
      loginMethod: user.loginMethod,
    };
    const updateSet: Record<string, unknown> = {};

    if (user.openId !== undefined) {
      values.openId = user.openId;
      updateSet.openId = user.openId;
    }
    if (user.azureAdId !== undefined) {
      values.azureAdId = user.azureAdId;
      updateSet.azureAdId = user.azureAdId;
    }
    if (user.name !== undefined) {
      values.name = user.name;
      updateSet.name = user.name;
    }
    if (user.passwordHash !== undefined) {
      values.passwordHash = user.passwordHash;
      updateSet.passwordHash = user.passwordHash;
    }
    if (user.isActive !== undefined) {
      values.isActive = user.isActive;
      updateSet.isActive = user.isActive;
    }
    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,
    });
  } catch (error) {
    console.error("[Database] Failed to upsert user:", error);
    throw error;
  }
}

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.length > 0 ? result[0] : undefined;
}

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

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

export async function createLocalUser(email: string, passwordHash: string, name: string, role: "user" | "admin" = "user") {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  
  await db.insert(users).values({
    email,
    passwordHash,
    name,
    loginMethod: "local",
    role,
    isActive: 1,
  });
  
  return getUserByEmail(email);
}

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

export async function updateUserPassword(userId: number, newPasswordHash: string) {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  await db.update(users).set({ passwordHash: newPasswordHash }).where(eq(users.id, userId));
}

export async function toggleUserActive(userId: number, isActive: number) {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  await db.update(users).set({ isActive }).where(eq(users.id, userId));
}

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

// ============= SOURCE FILE OPERATIONS =============

export async function createSourceFile(data: InsertSourceFile): Promise<SourceFile> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  
  const result = await db.insert(sourceFiles).values(data);
  const insertedId = Number(result[0].insertId);
  
  const inserted = await db.select().from(sourceFiles).where(eq(sourceFiles.id, insertedId)).limit(1);
  return inserted[0]!;
}

export async function getSourceFileById(id: number): Promise<SourceFile | undefined> {
  const db = await getDb();
  if (!db) return undefined;
  const result = await db.select().from(sourceFiles).where(eq(sourceFiles.id, id)).limit(1);
  return result[0];
}

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

export async function getSourceFilesByUserId(userId: number): Promise<SourceFile[]> {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(sourceFiles).where(eq(sourceFiles.userId, userId)).orderBy(desc(sourceFiles.createdAt));
}

// ============= INVOICE OPERATIONS =============

export async function createInvoice(data: InsertInvoice): Promise<Invoice> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  
  const result = await db.insert(invoices).values(data);
  const insertedId = Number(result[0].insertId);
  
  const inserted = await db.select().from(invoices).where(eq(invoices.id, insertedId)).limit(1);
  return inserted[0]!;
}

export async function getInvoiceById(id: number): Promise<Invoice | undefined> {
  const db = await getDb();
  if (!db) return undefined;
  const result = await db.select().from(invoices).where(eq(invoices.id, id)).limit(1);
  return result[0];
}

export async function getInvoicesByUserId(userId: number): Promise<Invoice[]> {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(invoices).where(eq(invoices.userId, userId)).orderBy(desc(invoices.createdAt));
}

export async function getInvoicesByUser(userId: number): Promise<Invoice[]> {
  return getInvoicesByUserId(userId);
}

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

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

export async function searchInvoices(userId: number, query: string): Promise<Invoice[]> {
  const db = await getDb();
  if (!db) return [];
  
  const searchPattern = `%${query}%`;
  return db.select().from(invoices)
    .where(
      and(
        eq(invoices.userId, userId),
        sql`(${invoices.supplierName} LIKE ${searchPattern} OR ${invoices.invoiceNumber} LIKE ${searchPattern})`
      )
    )
    .orderBy(desc(invoices.createdAt));
}

export async function getInvoiceStats(userId: number) {
  const db = await getDb();
  if (!db) return { 
    total: 0, 
    completed: 0, 
    processing: 0, 
    error: 0,
    totalAmount: 0,
    averageScore: 0,
    lastActivity: null,
    weeklyData: [],
    topSuppliers: [],
    suppliersList: []
  };
  
  const allInvoices = await getInvoicesByUserId(userId);
  
  // Calculate basic stats
  const completed = allInvoices.filter(i => i.status === "completed");
  const totalAmount = completed.reduce((sum, inv) => sum + (Number(inv.totalAmount) || 0), 0);
  const averageScore = completed.length > 0 
    ? completed.reduce((sum, inv) => sum + (inv.qualityScore || 0), 0) / completed.length 
    : 0;
  
  // Get last activity
  const sortedByDate = [...allInvoices].sort((a, b) => 
    new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime()
  );
  const lastActivity = sortedByDate[0]?.createdAt || null;
  
  // Calculate weekly data (last 30 days)
  const now = new Date();
  const thirtyDaysAgo = new Date(now.getTime() - 30 * 24 * 60 * 60 * 1000);
  const weeklyMap = new Map<string, number>();
  
  allInvoices.forEach(inv => {
    const date = new Date(inv.createdAt);
    if (date >= thirtyDaysAgo) {
      const weekStart = new Date(date);
      weekStart.setDate(date.getDate() - date.getDay()); // Start of week
      const weekKey = `${weekStart.getDate().toString().padStart(2, '0')}/${(weekStart.getMonth() + 1).toString().padStart(2, '0')}`;
      weeklyMap.set(weekKey, (weeklyMap.get(weekKey) || 0) + 1);
    }
  });
  
  const weeklyData = Array.from(weeklyMap.entries())
    .map(([week, count]) => ({ week, count }))
    .sort((a, b) => {
      const [dayA, monthA] = a.week.split('/').map(Number);
      const [dayB, monthB] = b.week.split('/').map(Number);
      return (monthA! * 100 + dayA!) - (monthB! * 100 + dayB!);
    });
  
  // Calculate top suppliers
  const supplierMap = new Map<string, { count: number; amount: number }>();
  completed.forEach(inv => {
    const supplier = inv.supplierName || 'Inconnu';
    const current = supplierMap.get(supplier) || { count: 0, amount: 0 };
    supplierMap.set(supplier, {
      count: current.count + 1,
      amount: current.amount + (Number(inv.totalAmount) || 0)
    });
  });
  
  const topSuppliers = Array.from(supplierMap.entries())
    .map(([name, data]) => ({
      name,
      count: data.count,
      amount: data.amount,
      percentage: completed.length > 0 ? (data.count / completed.length * 100) : 0
    }))
    .sort((a, b) => b.count - a.count)
    .slice(0, 10);
  
  const suppliersList = Array.from(supplierMap.entries())
    .map(([name, data]) => ({
      name,
      count: data.count,
      amount: data.amount
    }))
    .sort((a, b) => b.count - a.count);
  
  return {
    total: allInvoices.length,
    completed: completed.length,
    processing: allInvoices.filter(i => i.status === "processing").length,
    error: allInvoices.filter(i => i.status === "error").length,
    totalAmount,
    averageScore: Math.round(averageScore),
    lastActivity,
    weeklyData,
    topSuppliers,
    suppliersList
  };
}

export async function findDuplicateInvoice(
  supplierName: string | null,
  invoiceNumber: string | null,
  invoiceDate: Date | null
): Promise<Invoice | undefined> {
  if (!supplierName || !invoiceNumber || !invoiceDate) return undefined;
  
  const db = await getDb();
  if (!db) return undefined;
  
  const result = await db.select().from(invoices)
    .where(
      and(
        eq(invoices.supplierName, supplierName),
        eq(invoices.invoiceNumber, invoiceNumber),
        eq(invoices.invoiceDate, invoiceDate)
      )
    )
    .limit(1);
  
  return result[0];
}

// ============= USER SETTINGS OPERATIONS =============

export async function getUserSettings(userId: number): Promise<UserSettings | undefined> {
  const db = await getDb();
  if (!db) return undefined;
  const result = await db.select().from(userSettings).where(eq(userSettings.userId, userId)).limit(1);
  return result[0];
}

export async function upsertUserSettings(data: InsertUserSettings) {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  
  const existing = await getUserSettings(data.userId);
  
  if (existing) {
    await db.update(userSettings).set(data).where(eq(userSettings.userId, data.userId));
  } else {
    await db.insert(userSettings).values(data);
  }
}

// ============= IMPORT LOG OPERATIONS =============

export async function createImportLog(data: InsertImportLog): Promise<ImportLog> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  
  const result = await db.insert(importLogs).values(data);
  const insertedId = Number(result[0].insertId);
  
  const inserted = await db.select().from(importLogs).where(eq(importLogs.id, insertedId)).limit(1);
  return inserted[0]!;
}

export async function getImportLogsByUser(userId: number): Promise<ImportLog[]> {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(importLogs).where(eq(importLogs.userId, userId)).orderBy(desc(importLogs.importedAt));
}

export async function deleteAllImportLogs(userId: number): Promise<void> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  await db.delete(importLogs).where(eq(importLogs.userId, userId));
}

// ============= LLM LOG OPERATIONS =============

export async function createLlmLog(data: InsertLlmLog): Promise<LlmLog> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  
  const result = await db.insert(llmLogs).values(data);
  const insertedId = Number(result[0].insertId);
  
  const inserted = await db.select().from(llmLogs).where(eq(llmLogs.id, insertedId)).limit(1);
  return inserted[0]!;
}

export async function getLlmLogsBySourceFile(sourceFileId: number): Promise<LlmLog[]> {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(llmLogs).where(eq(llmLogs.sourceFileId, sourceFileId)).orderBy(desc(llmLogs.createdAt));
}

export async function getLlmLogsByInvoice(invoiceId: number): Promise<LlmLog[]> {
  const db = await getDb();
  if (!db) return [];
  return db.select().from(llmLogs).where(eq(llmLogs.invoiceId, invoiceId)).orderBy(desc(llmLogs.createdAt));
}

// ============= IMPORT SETTINGS OPERATIONS =============

export async function getImportSettingsByUser(userId: number): Promise<ImportSettings | null> {
  const db = await getDb();
  if (!db) return null;
  const result = await db.select().from(importSettings).where(eq(importSettings.userId, userId)).limit(1);
  return result[0] || null;
}

export async function upsertImportSettings(data: InsertImportSettings): Promise<ImportSettings> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  
  // Check if settings exist for this user
  const existing = await getImportSettingsByUser(data.userId!);
  
  if (existing) {
    // Update existing settings
    await db.update(importSettings)
      .set({
        ...data,
        updatedAt: new Date(),
      })
      .where(eq(importSettings.userId, data.userId!));
    
    const updated = await getImportSettingsByUser(data.userId!);
    return updated!;
  } else {
    // Insert new settings
    const result = await db.insert(importSettings).values(data);
    const insertedId = Number(result[0].insertId);
    
    const inserted = await db.select().from(importSettings).where(eq(importSettings.id, insertedId)).limit(1);
    return inserted[0]!;
  }
}

// ============= DEPARTMENT LIST OPERATIONS =============

export async function getDepartmentsByUser(userId: number): Promise<Department[]> {
  const db = await getDb();
  if (!db) return [];
  return await db.select().from(departmentList).where(eq(departmentList.userId, userId)).orderBy(departmentList.name);
}

export async function createDepartment(data: InsertDepartment): Promise<Department> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  const [department] = await db.insert(departmentList).values(data).$returningId();
  return await db.select().from(departmentList).where(eq(departmentList.id, department.id)).then(rows => rows[0]);
}

export async function deleteDepartment(id: number): Promise<void> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  await db.delete(departmentList).where(eq(departmentList.id, id));
}

// ============= ACCOUNTING ALLOCATION LIST OPERATIONS =============

export async function getAccountingAllocationsByUser(userId: number): Promise<AccountingAllocation[]> {
  const db = await getDb();
  if (!db) return [];
  return await db.select().from(accountingAllocationList).where(eq(accountingAllocationList.userId, userId)).orderBy(accountingAllocationList.name);
}

export async function createAccountingAllocation(data: InsertAccountingAllocation): Promise<AccountingAllocation> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  const [allocation] = await db.insert(accountingAllocationList).values(data).$returningId();
  return await db.select().from(accountingAllocationList).where(eq(accountingAllocationList.id, allocation.id)).then(rows => rows[0]);
}

export async function deleteAccountingAllocation(id: number): Promise<void> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  await db.delete(accountingAllocationList).where(eq(accountingAllocationList.id, id));
}

// ============= AUTOMATION RULES OPERATIONS =============

export async function getAutomationRulesByUser(userId: number): Promise<AutomationRule[]> {
  const db = await getDb();
  if (!db) return [];
  return await db.select().from(automationRules).where(eq(automationRules.userId, userId)).orderBy(automationRules.priority);
}

export async function getAutomationRuleById(id: number): Promise<AutomationRule | null> {
  const db = await getDb();
  if (!db) return null;
  const result = await db.select().from(automationRules).where(eq(automationRules.id, id)).limit(1);
  return result[0] || null;
}

export async function createAutomationRule(data: InsertAutomationRule): Promise<AutomationRule> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  const result = await db.insert(automationRules).values(data);
  const insertedId = result[0].insertId;
  const newRule = await getAutomationRuleById(insertedId);
  return newRule!;
}

export async function updateAutomationRule(id: number, data: Partial<InsertAutomationRule>): Promise<AutomationRule> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  await db.update(automationRules).set(data).where(eq(automationRules.id, id));
  const updated = await getAutomationRuleById(id);
  return updated!;
}

export async function deleteAutomationRule(id: number): Promise<void> {
  const db = await getDb();
  if (!db) throw new Error("Database not available");
  await db.delete(automationRules).where(eq(automationRules.id, id));
}

// ============= INITIALIZE DEFAULT VALUES =============

export async function initializeDefaultLists(userId: number): Promise<void> {
  const db = await getDb();
  if (!db) return;
  
  // Initialize default departments
  const defaultDepartments = ["DSI", "TRAVAUX", "AUTRE"];
  const existingDepts = await db.select().from(departmentList).where(eq(departmentList.userId, userId));
  const existingDeptNames = new Set(existingDepts.map(d => d.name));
  
  for (const name of defaultDepartments) {
    if (!existingDeptNames.has(name)) {
      try {
        await db.insert(departmentList).values({ userId, name });
      } catch (error) {
        // Ignore errors
      }
    }
  }
  
  // Initialize default accounting allocations
  const defaultAllocations = ["TOUS", "PA", "HEP", "SANITAIRE", "AUTRE"];
  const existingAllocs = await db.select().from(accountingAllocationList).where(eq(accountingAllocationList.userId, userId));
  const existingAllocNames = new Set(existingAllocs.map(a => a.name));
  
  for (const name of defaultAllocations) {
    if (!existingAllocNames.has(name)) {
      try {
        await db.insert(accountingAllocationList).values({ userId, name });
      } catch (error) {
        // Ignore errors
      }
    }
  }
}