const NewsletterSubscription = require("../models/newsletterSubscription");

const emailPattern = /^\S+@\S+\.\S+$/;

function cleanString(value) {
  return String(value || "").trim();
}

function normalizeEmail(value) {
  return cleanString(value).toLowerCase();
}

function toSubmissionShape(item) {
  return {
    _id: item._id,
    source: "newsletter",
    name: item.email,
    email: item.email,
    phone: "",
    pageUrl: item.pageUrl || "",
    status: item.status,
    internalNote: item.internalNote || "",
    ipAddress: item.ipAddress || "",
    userAgent: item.userAgent || "",
    payload: {
      email: item.email,
    },
    createdAt: item.createdAt,
    updatedAt: item.updatedAt,
  };
}

function buildListQuery(query) {
  const mongoQuery = {};
  const search = cleanString(query.search);
  const status = cleanString(query.status);

  if (status && NewsletterSubscription.STATUSES.includes(status)) {
    mongoQuery.status = status;
  }

  if (query.startDate || query.endDate) {
    mongoQuery.createdAt = {};
    if (query.startDate) {
      mongoQuery.createdAt.$gte = new Date(query.startDate);
    }
    if (query.endDate) {
      const end = new Date(query.endDate);
      end.setHours(23, 59, 59, 999);
      mongoQuery.createdAt.$lte = end;
    }
  }

  if (search) {
    mongoQuery.email = new RegExp(
      search.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"),
      "i",
    );
  }

  return mongoQuery;
}

exports.subscribe = async (req, res) => {
  try {
    const email = normalizeEmail(req.body.email);

    if (!email || !emailPattern.test(email)) {
      return res.status(400).json({ success: false, error: "Please enter a valid email" });
    }

    const subscription = await NewsletterSubscription.findOneAndUpdate(
      { email },
      {
        $set: {
          email,
          status: "subscribed",
          pageUrl: cleanString(req.body.pageUrl) || "/",
          ipAddress: req.ip || req.connection?.remoteAddress || "",
          userAgent: req.get("User-Agent") || "",
        },
        $setOnInsert: {
          internalNote: "",
        },
      },
      { new: true, upsert: true, runValidators: true, setDefaultsOnInsert: true },
    );

    return res.status(201).json({
      success: true,
      message: "Subscription received",
      data: {
        id: subscription._id,
        email: subscription.email,
        status: subscription.status,
      },
    });
  } catch (error) {
    if (error.name === "ValidationError") {
      const errors = Object.values(error.errors).map((item) => item.message);
      return res.status(400).json({ success: false, error: errors.join(", ") });
    }

    if (error.code === 11000) {
      return res.status(409).json({ success: false, error: "Email is already subscribed" });
    }

    console.error("newsletter.subscribe error:", error);
    return res.status(500).json({ success: false, error: "Error subscribing email" });
  }
};

exports.list = async (req, res) => {
  try {
    const page = Math.max(parseInt(req.query.page, 10) || 1, 1);
    const limit = Math.min(Math.max(parseInt(req.query.limit, 10) || 20, 1), 100);
    const skip = (page - 1) * limit;
    const query = buildListQuery(req.query);

    const [items, total] = await Promise.all([
      NewsletterSubscription.find(query)
        .sort({ createdAt: -1 })
        .skip(skip)
        .limit(limit)
        .lean(),
      NewsletterSubscription.countDocuments(query),
    ]);

    return res.json({
      success: true,
      data: items.map(toSubmissionShape),
      pagination: {
        page,
        limit,
        total,
        totalPages: Math.ceil(total / limit) || 1,
      },
    });
  } catch (error) {
    console.error("newsletter.list error:", error);
    return res.status(500).json({ success: false, error: "Error loading subscriptions" });
  }
};

exports.detail = async (req, res) => {
  try {
    const subscription = await NewsletterSubscription.findById(req.params.id).lean();
    if (!subscription) {
      return res.status(404).json({ success: false, error: "Subscription not found" });
    }
    return res.json({ success: true, data: toSubmissionShape(subscription) });
  } catch (error) {
    console.error("newsletter.detail error:", error);
    return res.status(500).json({ success: false, error: "Error loading subscription" });
  }
};

exports.update = async (req, res) => {
  try {
    const update = {};
    const status = cleanString(req.body.status);

    if (status) {
      if (!NewsletterSubscription.STATUSES.includes(status)) {
        return res.status(400).json({ success: false, error: "Invalid status" });
      }
      update.status = status;
    }

    if (req.body.internalNote !== undefined) {
      update.internalNote = cleanString(req.body.internalNote);
    }

    const subscription = await NewsletterSubscription.findByIdAndUpdate(
      req.params.id,
      update,
      { new: true, runValidators: true },
    );

    if (!subscription) {
      return res.status(404).json({ success: false, error: "Subscription not found" });
    }

    return res.json({ success: true, data: toSubmissionShape(subscription) });
  } catch (error) {
    if (error.name === "ValidationError") {
      const errors = Object.values(error.errors).map((item) => item.message);
      return res.status(400).json({ success: false, error: errors.join(", ") });
    }

    console.error("newsletter.update error:", error);
    return res.status(500).json({ success: false, error: "Error updating subscription" });
  }
};