const db = require("../models");

const VALID_QUARTERS = ["Q1", "Q2", "Q3", "Q4"];

async function createSubmissionWithProducts(transaction, payload) {
  const { year, establishment_id, product_id, data } = payload;

  for (const row of data) {
    const { quarter, qty, cost } = row;

    await db.sequelize.query(
      `
      INSERT INTO submission (
        establishment_id, quarter, year,
        edit_request, edit_access, status,
        created_by, created_at, updated_at,
        approve_reject_status
      )
      SELECT ?, ?, ?, 0, 0, 'Approved', 1,
        CASE ?
          WHEN 'Q1' THEN CONCAT(?, '-03-15 10:00:00')
          WHEN 'Q2' THEN CONCAT(?, '-06-15 10:00:00')
          WHEN 'Q3' THEN CONCAT(?, '-09-15 10:00:00')
          WHEN 'Q4' THEN CONCAT(?, '-12-15 10:00:00')
        END,
        CASE ?
          WHEN 'Q1' THEN CONCAT(?, '-03-15 10:00:00')
          WHEN 'Q2' THEN CONCAT(?, '-06-15 10:00:00')
          WHEN 'Q3' THEN CONCAT(?, '-09-15 10:00:00')
          WHEN 'Q4' THEN CONCAT(?, '-12-15 10:00:00')
        END,
        1
      WHERE NOT EXISTS (
        SELECT 1
        FROM submission
        WHERE establishment_id = ?
          AND quarter = ?
          AND year = ?
      )
    `,
      {
        replacements: [
          establishment_id,
          quarter,
          year,
          quarter,
          year,
          year,
          year,
          year,
          quarter,
          year,
          year,
          year,
          year,
          establishment_id,
          quarter,
          year,
        ],
        transaction,
      }
    );

    const submissionRows = await db.sequelize.query(
      `
      SELECT id
      FROM submission
      WHERE establishment_id = ?
        AND quarter = ?
        AND year = ?
      LIMIT 1
    `,
      {
        replacements: [establishment_id, quarter, year],
        type: db.Sequelize.QueryTypes.SELECT,
        transaction,
      }
    );

    if (!submissionRows.length) {
      throw new Error(`Submission not found for ${quarter}-${year}`);
    }

    const submission_id = submissionRows[0].id;

    await db.sequelize.query(
      `
      INSERT INTO submission_products (
        submission_id, product_id, unit_id,
        annual_installed_capacity,

        previous_quantity_period_one,
        previous_quantity_period_two,
        previous_quantity_period_three,

        previous_cost_period_one,
        previous_cost_period_two,
        previous_cost_period_three,

        current_quantity_period_one,
        current_quantity_period_two,
        current_quantity_period_three,

        current_cost_period_one,
        current_cost_period_two,
        current_cost_period_three,

        forecast_quantity_period_one,
        forecast_quantity_period_two,
        forecast_quantity_period_three,

        forecast_cost_period_one,
        forecast_cost_period_two,
        forecast_cost_period_three,

        previous_quantity, previous_cost,
        current_quantity, current_cost,
        forecast_quantity, forecast_cost,

        remarks, created_by, created_at, updated_at, is_active
      )
      SELECT ?, ?, 1, 50000,
        0, 0, 0,
        0, 0, 0,
        ?, ?, ?,
        ?, ?, ?,
        0, 0, 0,
        0, 0, 0,
        0, 0,
        ?, ?,
        0, 0,
        CONCAT(?, ' current only'),
        1, NOW(), NOW(), 1
      WHERE NOT EXISTS (
        SELECT 1
        FROM submission_products
        WHERE submission_id = ?
          AND product_id = ?
      )
    `,
      {
        replacements: [
          submission_id,
          product_id,
          qty / 3,
          qty / 3,
          qty / 3,
          cost / 3,
          cost / 3,
          cost / 3,
          qty,
          cost,
          quarter,
          submission_id,
          product_id,
        ],
        transaction,
      }
    );
  }
}

exports.createSubmissionWithProducts = async (req, res) => {
  const payloadList = Array.isArray(req.body) ? req.body : [req.body];

  if (!payloadList.length) {
    return res.status(400).json({
      success: false,
      message: "Request body must be a non-empty array",
    });
  }

  const invalidItem = payloadList.find(
    (item) =>
      !item ||
      !item.year ||
      !item.establishment_id ||
      !item.product_id ||
      !Array.isArray(item.data) ||
      item.data.length === 0
  );
  if (invalidItem) {
    return res.status(400).json({
      success: false,
      message:
        "Each payload item must contain year, establishment_id, product_id and non-empty data array",
    });
  }

  const invalidQuarterItem = payloadList.find((item) =>
    item.data.some((row) => !VALID_QUARTERS.includes(row?.quarter))
  );
  if (invalidQuarterItem) {
    const invalidQuarterRow = invalidQuarterItem.data.find(
      (row) => !VALID_QUARTERS.includes(row?.quarter)
    );
    return res.status(400).json({
      success: false,
      message: `Invalid quarter '${invalidQuarterRow.quarter}'. Allowed: Q1, Q2, Q3, Q4`,
    });
  }

  const invalidNumberItem = payloadList.find((item) =>
    item.data.some((row) => Number.isNaN(Number(row?.qty)) || Number.isNaN(Number(row?.cost)))
  );
  if (invalidNumberItem) {
    return res.status(400).json({
      success: false,
      message: "Each data row in each payload item must contain numeric qty and cost values",
    });
  }

  const transaction = await db.sequelize.transaction();
  try {
    for (const item of payloadList) {
      await createSubmissionWithProducts(transaction, {
        year: Number(item.year),
        establishment_id: Number(item.establishment_id),
        product_id: Number(item.product_id),
        data: item.data.map((row) => ({
          quarter: row.quarter,
          qty: Number(row.qty),
          cost: Number(row.cost),
        })),
      });
    }

    await transaction.commit();

    return res.status(201).json({
      success: true,
      message: "Submission and submission products processed successfully",
      total_payload_items: payloadList.length,
    });
  } catch (error) {
    await transaction.rollback();
    return res.status(500).json({
      success: false,
      message: "Failed to process submission data",
      error: error.message,
    });
  }
};