package controller

import (
	"fmt"
	"strconv"
	"strings"
	"time"

	"github.com/gofiber/fiber/v2"
	"github.com/xuri/excelize/v2"
	entity "gitlab.com/mbugroup/lti-api.git/internal/entities"
)

const transactionExportSheetName = "Transaksi"

func exportTransactionListExcel(c *fiber.Ctx, payments []entity.Payment) error {
	content, err := buildTransactionExportWorkbook(payments)
	if err != nil {
		return fiber.NewError(fiber.StatusInternalServerError, "failed to generate excel file")
	}

	filename := fmt.Sprintf("transaksi_%s.xlsx", time.Now().Format("20060102_150405"))
	c.Set("Content-Type", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
	c.Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s"`, filename))
	return c.Status(fiber.StatusOK).Send(content)
}

func buildTransactionExportWorkbook(payments []entity.Payment) ([]byte, error) {
	file := excelize.NewFile()
	defer file.Close()

	defaultSheet := file.GetSheetName(file.GetActiveSheetIndex())
	if defaultSheet != transactionExportSheetName {
		if err := file.SetSheetName(defaultSheet, transactionExportSheetName); err != nil {
			return nil, err
		}
	}

	if err := setTransactionExportColumns(file); err != nil {
		return nil, err
	}
	if err := setTransactionExportHeaders(file); err != nil {
		return nil, err
	}
	if err := setTransactionExportRows(file, payments); err != nil {
		return nil, err
	}
	if err := file.SetPanes(transactionExportSheetName, &excelize.Panes{
		Freeze:      true,
		YSplit:      1,
		TopLeftCell: "A2",
		ActivePane:  "bottomLeft",
	}); err != nil {
		return nil, err
	}

	buffer, err := file.WriteToBuffer()
	if err != nil {
		return nil, err
	}

	return buffer.Bytes(), nil
}

func setTransactionExportColumns(file *excelize.File) error {
	columnWidths := map[string]float64{
		"A": 20,
		"B": 22,
		"C": 18,
		"D": 25,
		"E": 14,
		"F": 16,
		"G": 16,
		"H": 22,
		"I": 22,
		"J": 18,
		"K": 18,
		"L": 18,
		"M": 30,
		"N": 22,
		"O": 20,
	}

	sheet := transactionExportSheetName
	for col, width := range columnWidths {
		if err := file.SetColWidth(sheet, col, col, width); err != nil {
			return err
		}
	}

	return file.SetRowHeight(sheet, 1, 24)
}

func setTransactionExportHeaders(file *excelize.File) error {
	sheet := transactionExportSheetName
	headers := []string{
		"Kode Pembayaran",
		"No. Referensi",
		"Tipe Transaksi",
		"Pihak",
		"Tipe Pihak",
		"Tanggal Bayar",
		"Metode Bayar",
		"Bank",
		"No. Rekening Bank",
		"Pemasukan",
		"Pengeluaran",
		"Nominal",
		"Catatan",
		"Dibuat Oleh",
		"Status",
	}

	for i, header := range headers {
		colName, err := excelize.ColumnNumberToName(i + 1)
		if err != nil {
			return err
		}
		if err := file.SetCellValue(sheet, colName+"1", header); err != nil {
			return err
		}
	}

	headerStyle, err := file.NewStyle(&excelize.Style{
		Font:      &excelize.Font{Bold: true, Color: "1F2937"},
		Fill:      excelize.Fill{Type: "pattern", Pattern: 1, Color: []string{"DCEBFA"}},
		Alignment: &excelize.Alignment{Horizontal: "center", Vertical: "center"},
		Border: []excelize.Border{
			{Type: "left", Color: "D1D5DB", Style: 1},
			{Type: "top", Color: "D1D5DB", Style: 1},
			{Type: "bottom", Color: "D1D5DB", Style: 1},
			{Type: "right", Color: "D1D5DB", Style: 1},
		},
	})
	if err != nil {
		return err
	}

	return file.SetCellStyle(sheet, "A1", "O1", headerStyle)
}

func setTransactionExportRows(file *excelize.File, payments []entity.Payment) error {
	if len(payments) == 0 {
		return nil
	}

	sheet := transactionExportSheetName
	for i, p := range payments {
		row := strconv.Itoa(i + 2)
		if err := writeTransactionExportRow(file, sheet, row, p); err != nil {
			return err
		}
	}

	lastRow := strconv.Itoa(len(payments) + 1)

	dataStyle, err := file.NewStyle(&excelize.Style{
		Alignment: &excelize.Alignment{Horizontal: "left", Vertical: "center", WrapText: true},
		Border: []excelize.Border{
			{Type: "left", Color: "D1D5DB", Style: 1},
			{Type: "top", Color: "D1D5DB", Style: 1},
			{Type: "bottom", Color: "D1D5DB", Style: 1},
			{Type: "right", Color: "D1D5DB", Style: 1},
		},
	})
	if err != nil {
		return err
	}
	if err := file.SetCellStyle(sheet, "A2", "O"+lastRow, dataStyle); err != nil {
		return err
	}

	numericStyle, err := file.NewStyle(&excelize.Style{
		Alignment: &excelize.Alignment{Horizontal: "right", Vertical: "center"},
		Border: []excelize.Border{
			{Type: "left", Color: "D1D5DB", Style: 1},
			{Type: "top", Color: "D1D5DB", Style: 1},
			{Type: "bottom", Color: "D1D5DB", Style: 1},
			{Type: "right", Color: "D1D5DB", Style: 1},
		},
	})
	if err != nil {
		return err
	}

	return file.SetCellStyle(sheet, "J2", "L"+lastRow, numericStyle)
}

func writeTransactionExportRow(file *excelize.File, sheet, row string, p entity.Payment) error {
	incomeAmount, expenseAmount := txAmounts(p.Direction, p.Nominal)

	values := []interface{}{
		safeTxText(p.PaymentCode),
		safeTxRefNumber(p.ReferenceNumber),
		safeTxText(txTransactionType(p)),
		safeTxText(txPartyName(p)),
		safeTxText(p.PartyType),
		formatTxDate(p.PaymentDate),
		safeTxText(p.PaymentMethod),
		safeTxBank(p),
		safeTxBankAccount(p),
		incomeAmount,
		expenseAmount,
		p.Nominal,
		safeTxText(p.Notes),
		safeTxText(txCreatedBy(p)),
		formatTxStatus(p),
	}

	for colIdx, val := range values {
		colName, err := excelize.ColumnNumberToName(colIdx + 1)
		if err != nil {
			return err
		}
		if err := file.SetCellValue(sheet, colName+row, val); err != nil {
			return err
		}
	}

	return nil
}

func safeTxText(s string) string {
	trimmed := strings.TrimSpace(s)
	if trimmed == "" {
		return "-"
	}
	return trimmed
}

func safeTxRefNumber(s *string) string {
	if s == nil {
		return "-"
	}
	return safeTxText(*s)
}

func safeTxBank(p entity.Payment) string {
	if p.BankWarehouse.Id == 0 {
		return "-"
	}
	return safeTxText(p.BankWarehouse.Name)
}

func safeTxBankAccount(p entity.Payment) string {
	if p.BankWarehouse.Id == 0 {
		return "-"
	}
	return safeTxText(p.BankWarehouse.AccountNumber)
}

func formatTxDate(t time.Time) string {
	if t.IsZero() {
		return "-"
	}
	loc, err := time.LoadLocation("Asia/Jakarta")
	if err == nil {
		t = t.In(loc)
	}
	return t.Format("02-01-2006")
}

func formatTxStatus(p entity.Payment) string {
	if p.LatestApproval == nil {
		return "-"
	}
	return safeTxText(p.LatestApproval.StepName)
}

func txTransactionType(p entity.Payment) string {
	if p.TransactionType != "" {
		return p.TransactionType
	}
	return p.Direction
}

func txPartyName(p entity.Payment) string {
	switch p.PartyType {
	case "CUSTOMER":
		if p.Customer != nil && p.Customer.Id != 0 {
			return p.Customer.Name
		}
	case "SUPPLIER":
		if p.Supplier != nil && p.Supplier.Id != 0 {
			return p.Supplier.Name
		}
	}
	return ""
}

func txCreatedBy(p entity.Payment) string {
	if p.CreatedUser.Id == 0 {
		return ""
	}
	return p.CreatedUser.Name
}

func txAmounts(direction string, nominal float64) (income, expense float64) {
	switch strings.ToUpper(direction) {
	case "IN":
		return nominal, 0
	case "OUT":
		return 0, nominal
	default:
		return 0, 0
	}
}