const { Sequelize, Op } = require("sequelize");
const { Establishment, Submission, Emirate, EstablishmentUser, SubmissionProduct, SubmissionDeadline } = require("../models");

function getQuarter(date) {
  const month = date.getMonth() + 1;
  if (month >= 4 && month <= 6) return "Q1";
  if (month >= 7 && month <= 9) return "Q2";
  if (month >= 10 && month <= 12) return "Q3";
  return "Q4"; // Jan-Mar
}

function getQuarterDates(quarter, year) {
  switch (quarter) {
    case "Q1":
      return { start: new Date(year, 3, 1), end: new Date(year, 5, 30) };
    case "Q2":
      return { start: new Date(year, 6, 1), end: new Date(year, 8, 30) };
    case "Q3":
      return { start: new Date(year, 9, 1), end: new Date(year, 11, 31) };
    case "Q4":
      return { start: new Date(year, 0, 1), end: new Date(year, 2, 31) };
    default:
      return {};
  }
}

function getPrevCurrNextQuarter(date) {
  const month = date.getMonth() + 1; // 1-12
  const year = date.getFullYear();
  const quarters = ["Q1", "Q2", "Q3", "Q4"];

  // map month -> index: 0=Q1(Apr-Jun),1=Q2(Jul-Sep),2=Q3(Oct-Dec),3=Q4(Jan-Mar)
  const getQuarterIndex = (m) => {
    if (m >= 4 && m <= 6) return 0;   // Apr-Jun -> Q1
    if (m >= 7 && m <= 9) return 1;   // Jul-Sep -> Q2
    if (m >= 10 && m <= 12) return 2; // Oct-Dec -> Q3
    return 3;                          // Jan-Mar -> Q4
  };

  const currentIndex = getQuarterIndex(month);
  const currentQuarter = quarters[currentIndex];

  const previousIndex = (currentIndex - 1 + 4) % 4;
  const nextIndex = (currentIndex + 1) % 4;

  const previousQuarter = quarters[previousIndex];
  const nextQuarter = quarters[nextIndex];

  const previousQuarterYear = (currentIndex === 3) ? year - 1 : year;
  const nextQuarterYear = (currentIndex === 2) ? year + 1 : year;

  return {
    previous_quarter: previousQuarter,
    previous_quarter_year: previousQuarterYear,
    current_quarter: currentQuarter,
    current_quarter_year: year,
    next_quarter: nextQuarter,
    next_quarter_year: nextQuarterYear,
  };
}

  


exports.getEstablishmentDashboard = async (req, res) => {
  try {
    const establishment_id = req.query.establishment_id;
    if (!establishment_id) {
      return res.status(400).json({ status: "failed", message: "establishment_id required" });
    }

    const today = new Date();
    const quarters = getPrevCurrNextQuarter(today);



    const submission_history = await Submission.findAll({
      where: { establishment_id },
      order: [["created_at", "DESC"]],
      limit: 5,
      attributes: {
        include: [
          [
            Sequelize.literal(`(
              SELECT COUNT(*) 
              FROM submission_products AS sp 
              WHERE sp.submission_id = submission.id
            )`),
            "product_count",
          ],
        ],
      },
     
    });
    

    // Submission status for current quarter
    const currentQuarterDates = getQuarterDates(quarters.current_quarter, quarters.current_quarter_year);

    const currentSubmission = await Submission.findOne({
      where: {
        establishment_id,
        quarter: quarters.current_quarter,
        year: quarters.current_quarter_year,
      },
      order: [["created_at", "DESC"]],
    });

    // Get submission deadline (assuming only one row)
    const deadline = await SubmissionDeadline.findByPk(1);

    let nextDeadline = null;
    let submissionStatus = "Pending";

    if (deadline) {
      const quarterEnd = currentQuarterDates.end;
      const deadlineDate = new Date(quarterEnd);
      deadlineDate.setDate(deadlineDate.getDate() + deadline.deadline_days_after_quarter_end);

      nextDeadline = deadlineDate;

      if (currentSubmission) {
        submissionStatus = "Submitted";
      }
    }

    let lastSubmissionInfo = null;
    if (submission_history.length > 0) {
      const last = submission_history[0];
      lastSubmissionInfo = {
        quarter: last.quarter,
        year: last.year,
        submitted_on: last.created_at,
      };
    }

    res.status(200).json({
      status: "success",
      data: {
        ...quarters,
        submission_status: submissionStatus,
        next_deadline: nextDeadline,
        last_submission: lastSubmissionInfo,
        submission_history,
      },
    });

  } catch (err) {
    console.error(err);
    res.status(500).json({ status: "failed", message: err.message });
  }
};

exports.adminDashboard = async (req, res) => {
  try {
    const { quarter, year } = req.query; // e.g., Q1, 2025

    // --- Summary Counts ---
    const [
      totalEstablishments,
      submittedCount,
      approvedCount,
      rejectedCount,
      pendingCount
    ] = await Promise.all([
      Establishment.count(),
      Submission.count(),
      Submission.count({ where: { status: "Approved" } }),
      Submission.count({ where: { status: "Rejected" } }),
      Submission.count({ where: { status: "Pending" } }),
    ]);

    // Not Started = total establishments - those that have any submission
    const startedEstIds = await Submission.findAll({
      attributes: [[Sequelize.fn("DISTINCT", Sequelize.col("establishment_id")), "id"]],
      raw: true,
    });
    const startedIds = startedEstIds.map(e => e.id);
    const notStartedCount = await Establishment.count({
      where: { id: { [Op.notIn]: startedIds } },
    });

    // ---  Recent 10 submissions for given quarter & year ---
    const whereCond = {};
    if (quarter) whereCond.quarter = quarter;
    if (year) whereCond.year = year;

    const recentSubmissions = await Submission.findAll({
      where: whereCond,
      include: [
        {
          model: Establishment,
          as: "establishment",
          attributes: ["factory_name"],
          include: [
            { model: Emirate, as: "establishment_emirate", attributes: ["name"] },
          ],
        },
        {
          model: EstablishmentUser,
          as: "created_user",
          attributes: ["name"],
        },
      ],
      attributes: {
        include: [
          [
            Sequelize.literal(`(
              SELECT COUNT(*) 
              FROM submission_products AS sp 
              WHERE sp.submission_id = submission.id
            )`),
            "product_count",
          ],
        ],
      },
      order: [["created_at", "DESC"]],
      limit: 10,
    });

    // ---  Send Response ---
    return res.status(200).json({
      status: "success",
      summary: {
        total_establishments: totalEstablishments,
        submitted: submittedCount,
        approved: approvedCount,
        rejected: rejectedCount,
        pending: pendingCount,
        not_started: notStartedCount,
      },
      recent_submissions: recentSubmissions,
    });
  } catch (err) {
    console.error(err);
    return res.status(500).json({ status: "failed", message: err.message });
  }
};