"use server";

import { getDb } from "@/lib/mongodb";
import { getLoggedInUser, logoutUser } from "@/lib/actions/auth";
import bcrypt from 'bcryptjs';
import { differenceInHours } from 'date-fns';
import type { User, Deployment } from "@/lib/types";
import type { TransferCoinsInput, ChangePasswordInput, UpdateProfileInput, DeleteAccountInput } from "@/lib/schemas";
import { revalidatePath } from 'next/cache';

const DAILY_COIN_AMOUNT = 10;
const CLAIM_COOLDOWN_HOURS = 24;

export async function claimDailyCoins(): Promise<{ success: boolean; message: string; newBalance?: number; nextClaimAvailableInMs?: number }> {
  const user = await getLoggedInUser();
  if (!user) {
    return { success: false, message: "You must be logged in to claim coins." };
  }

  const now = new Date();
  if (user.lastCoinClaim) {
    const hoursSinceLastClaim = differenceInHours(now, new Date(user.lastCoinClaim));
    if (hoursSinceLastClaim < CLAIM_COOLDOWN_HOURS) {
      const nextClaimTime = new Date(user.lastCoinClaim).getTime() + CLAIM_COOLDOWN_HOURS * 60 * 60 * 1000;
      const nextClaimAvailableInMs = Math.max(0, nextClaimTime - now.getTime());
      return {
        success: false,
        message: `You can claim again in ${CLAIM_COOLDOWN_HOURS - hoursSinceLastClaim} hour(s).`,
        nextClaimAvailableInMs
      };
    }
  }

  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");

    // Query by string _id directly
    const updatedUserResult = await usersCollection.findOneAndUpdate(
      { _id: user._id }, 
      {
        $inc: { coins: DAILY_COIN_AMOUNT },
        $set: { lastCoinClaim: now }
      },
      { returnDocument: "after" }
    );

    if (!updatedUserResult) {
      return { success: false, message: "Failed to update user balance. User not found or update failed." };
    }
    revalidatePath("/dashboard");
    return {
      success: true,
      message: `Successfully claimed ${DAILY_COIN_AMOUNT} coins!`,
      newBalance: updatedUserResult.coins,
      nextClaimAvailableInMs: CLAIM_COOLDOWN_HOURS * 60 * 60 * 1000
    };
  } catch (error) {
    console.error("Error claiming daily coins:", error);
    return { success: false, message: "An unexpected error occurred." };
  }
}

export async function transferCoins(data: TransferCoinsInput): Promise<{ success: boolean; message: string; newSenderBalance?: number }> {
  const sender = await getLoggedInUser();
  if (!sender) {
    return { success: false, message: "You must be logged in to transfer coins." };
  }

  if (data.amount <= 0) {
    return { success: false, message: "Transfer amount must be positive." };
  }
  if (sender.coins < data.amount && sender.role !== 'admin') {
    return { success: false, message: "Insufficient coin balance." };
  }
  if (sender.email === data.recipientEmail) {
    return { success: false, message: "You cannot transfer coins to yourself." };
  }

  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");

    const recipient = await usersCollection.findOne({ email: data.recipientEmail });
    if (!recipient) {
      return { success: false, message: "Recipient user not found." };
    }

    if (sender.role !== 'admin') {
        // Query by string _id directly
        const freshSenderData = await usersCollection.findOne({ _id: sender._id });
        if (!freshSenderData || freshSenderData.coins < data.amount) {
            return { success: false, message: "Insufficient coin balance. Please refresh and try again." };
        }
    }

    const senderUpdateResult = await usersCollection.updateOne(
      { _id: sender._id }, // Query by string _id
      { $inc: { coins: -data.amount } }
    );

    if (senderUpdateResult.modifiedCount === 0) {
      if (sender.role !== 'admin') { 
        return { success: false, message: "Failed to update your balance. Please try again." };
      }
    }

    const recipientUpdateResult = await usersCollection.updateOne(
      { _id: recipient._id }, // Query by string _id
      { $inc: { coins: data.amount } }
    );

    if (recipientUpdateResult.modifiedCount === 0) {
      // Rollback sender's coins if recipient update failed
      await usersCollection.updateOne(
        { _id: sender._id }, // Query by string _id
        { $inc: { coins: data.amount } }
      );
      return { success: false, message: "Failed to transfer coins to recipient. Your balance has been restored." };
    }

    const newSenderData = await usersCollection.findOne({ _id: sender._id }); // Query by string _id
    revalidatePath("/dashboard");
    return {
      success: true,
      message: `Successfully transferred ${data.amount} coins to ${recipient.name}.`,
      newSenderBalance: newSenderData?.coins ?? sender.coins - data.amount,
    };

  } catch (error) {
    console.error("Error transferring coins:", error);
    return { success: false, message: "An unexpected error occurred during the transfer." };
  }
}

export async function updateProfile(data: UpdateProfileInput): Promise<{ success: boolean; message: string }> {
  const loggedInUser = await getLoggedInUser();
  if (!loggedInUser) {
    return { success: false, message: "You must be logged in to update your profile." };
  }

  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");

    const result = await usersCollection.updateOne(
      { _id: loggedInUser._id }, // Query by string _id
      { $set: { name: data.name } }
    );

    if (result.modifiedCount === 0 && result.matchedCount > 0) {
      return { success: true, message: "No changes detected in profile information." };
    }
    if (result.modifiedCount === 0) { 
      return { success: false, message: "Failed to update profile. User not found." };
    }

    revalidatePath('/dashboard/profile');
    revalidatePath('/dashboard');
    return { success: true, message: "Profile updated successfully." };
  } catch (error) {
    console.error("Error updating profile:", error);
    return { success: false, message: "An unexpected error occurred while updating profile." };
  }
}

export async function changePassword(data: ChangePasswordInput): Promise<{ success: boolean; message: string }> {
  const loggedInUser = await getLoggedInUser();
  if (!loggedInUser) {
    return { success: false, message: "You must be logged in to change your password." };
  }

  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");

    const userFromDb = await usersCollection.findOne({ _id: loggedInUser._id }); // Query by string _id
    if (!userFromDb) {
      return { success: false, message: "User not found." };
    }

    const isCurrentPasswordValid = await bcrypt.compare(data.currentPassword, userFromDb.passwordHash);
    if (!isCurrentPasswordValid) {
      return { success: false, message: "Incorrect current password." };
    }

    const newPasswordHash = await bcrypt.hash(data.newPassword, 10);
    await usersCollection.updateOne(
      { _id: loggedInUser._id }, // Query by string _id
      { $set: { passwordHash: newPasswordHash } }
    );

    return { success: true, message: "Password changed successfully." };
  } catch (error) {
    console.error("Error changing password:", error);
    return { success: false, message: "An unexpected error occurred while changing password." };
  }
}

export async function deleteUserAccount(data: DeleteAccountInput): Promise<{ success: boolean; message: string }> {
  const loggedInUser = await getLoggedInUser();
  if (!loggedInUser) {
    return { success: false, message: "You must be logged in to delete your account." };
  }

  try {
    const db = await getDb();
    const usersCollection = db.collection<User>("users");
    const deploymentsCollection = db.collection<Deployment>("deployments");

    const userFromDb = await usersCollection.findOne({ _id: loggedInUser._id }); // Query by string _id
    if (!userFromDb) {
      return { success: false, message: "User not found." };
    }

    const isCurrentPasswordValid = await bcrypt.compare(data.currentPassword, userFromDb.passwordHash);
    if (!isCurrentPasswordValid) {
      return { success: false, message: "Incorrect password. Account deletion failed." };
    }

    if (userFromDb.role === 'admin') {
      const adminCount = await usersCollection.countDocuments({ role: 'admin' });
      if (adminCount <= 1) {
        return { success: false, message: "Cannot delete the last admin account. Promote another user to admin first." };
      }
    }

    await deploymentsCollection.deleteMany({ userId: loggedInUser._id }); // Query by string _id

    const deleteResult = await usersCollection.deleteOne({ _id: loggedInUser._id }); // Query by string _id
    if (deleteResult.deletedCount === 0) {
      return { success: false, message: "Failed to delete user account from the database." };
    }

    await logoutUser(); 

    return { success: true, message: "Account and associated deployments deleted successfully. You have been logged out." };

  } catch (error) {
    console.error("Error deleting account:", error);
    if (error instanceof Error && error.message.includes('NEXT_REDIRECT')) {
        throw error; 
    }
    return { success: false, message: "An unexpected error occurred while deleting your account." };
  }
}