const { addBaseUrlToImages } = require("../utils/imageHelper");
const { normalizeIconClass } = require("../utils/iconOptions");
const StudentSupport = require("../models/studentSupport");
const writeAuditLog = require("../audit/writeAuditLog");
const diffObject = require("../audit/diffObject");
const AUDIT_ACTIONS = require("../constants/auditAction");

const SLUG = "student-support";

function emptyPageShape() {
  return {
    metadata: { title: "", description: "" },
    hero: {
      badge: "",
      title: "",
      description: "",
      primaryButton: { label: "", href: "" },
      secondaryButton: { label: "", href: "" },
      image: "",
      imageAlt: "",
    },
    directory: { title: "", subtitle: "", services: [] },
    contactSection: {
      heading: "",
      description: "",
      channels: [],
      form: {
        heading: "",
        fields: {
          firstName: { label: "", placeholder: "" },
          lastName: { label: "", placeholder: "" },
          studentId: { label: "", placeholder: "" },
          department: { label: "" },
          message: { label: "", placeholder: "" },
        },
        departments: [],
        submitLabel: "",
        successMessage: "",
      },
    },
  };
}

function parseJsonField(raw) {
  if (raw == null || raw === "") return null;
  if (typeof raw === "object") return raw;
  try {
    return JSON.parse(raw);
  } catch {
    return null;
  }
}

/** Chuẩn hoá mọi field icon theo whitelist (dropdown admin). */
function sanitizeIcons(payload) {
  if (!payload) return payload;
  if (payload.hero) {
    /* hero không có icon list */
  }
  if (payload.directory?.services?.length) {
    payload.directory.services = payload.directory.services.map((s) => ({
      ...s,
      icon: normalizeIconClass(s.icon),
      hoursIcon: normalizeIconClass(s.hoursIcon),
    }));
  }
  if (payload.contactSection?.channels?.length) {
    payload.contactSection.channels = payload.contactSection.channels.map((c) => ({
      ...c,
      icon: normalizeIconClass(c.icon),
    }));
  }
  return payload;
}

async function getDocument() {
  return StudentSupport.findOne({ slug: SLUG }).lean();
}

/**
 * GET /api/student-support — public payload giống file JSON frontend (không kèm _id/slug).
 */
exports.api = async (req, res) => {
  try {
    const doc = await getDocument();
    if (!doc) {
      return res.status(404).json({ error: "Student Support content not found" });
    }
    const baseUrl =
      process.env.BACKEND_URL ?? `${req.protocol}://${req.get("host")}`;
    const body = {
      metadata: doc.metadata || {},
      hero: doc.hero || {},
      directory: doc.directory || { services: [] },
      contactSection: doc.contactSection || {},
    };
    res.json(addBaseUrlToImages(body, baseUrl));
  } catch (err) {
    console.error("studentSupport.api:", err);
    res.status(500).json({ error: "Error loading Student Support data" });
  }
};

exports.index = async (req, res) => {
  try {
    const doc = await getDocument();
    const data = doc
      ? {
          metadata: doc.metadata || {},
          hero: doc.hero || {},
          directory: doc.directory || { services: [] },
          contactSection: doc.contactSection || {},
        }
      : emptyPageShape();

    const { ICON_OPTIONS } = require("../utils/iconOptions");
    const frontendUrl = process.env.FRONTEND_URL || "";

    res.render("admin/student-support/index", {
      title: "Student Support",
      layout: "layouts/main",
      data,
      iconOptions: ICON_OPTIONS,
      frontendUrl,
      currentPath: req.path,
      user: req.session.user,
    });
  } catch (error) {
    console.error("studentSupport.index:", error);
    req.flash("error_msg", "Could not load Student Support page");
    res.redirect("/admin/dashboard");
  }
};

exports.update = async (req, res) => {
  try {
    const metadata = parseJsonField(req.body.metadata);
    const hero = parseJsonField(req.body.hero);
    const directory = parseJsonField(req.body.directory);
    const contactSection = parseJsonField(req.body.contactSection);

    if (!metadata || !hero || !directory || !contactSection) {
      req.flash("error_msg", "Invalid form payload. Please try again.");
      return res.redirect("/admin/student-support");
    }

    const payload = sanitizeIcons({
      metadata,
      hero,
      directory,
      contactSection,
    });

    let doc = await StudentSupport.findOne({ slug: SLUG });
    const beforeData = doc ? JSON.parse(JSON.stringify(doc.toObject())) : {};

    if (!doc) {
      doc = new StudentSupport({ slug: SLUG, ...payload });
    } else {
      doc.set(payload);
    }

    await doc.save();
    const afterData = JSON.parse(JSON.stringify(doc.toObject()));

    const changes = diffObject(beforeData, afterData);
    if (changes.length > 0) {
      await writeAuditLog({
        model: "StudentSupport",
        documentId: doc._id,
        action: AUDIT_ACTIONS.UPDATE_STUDENT_SUPPORT,
        before: beforeData,
        after: afterData,
        changes,
        req,
      });
    }

    req.flash("success_msg", "Student Support updated successfully");
    res.redirect("/admin/student-support");
  } catch (err) {
    console.error("studentSupport.update:", err);
    req.flash("error_msg", err.message || "Error updating Student Support");
    res.redirect("/admin/student-support");
  }
};