package utils

import (
	"encoding/csv"
	"io"
	"strings"
)

type CSVParseResult struct {
	ICCIDs      []string
	TotalCount  int
	ParseErrors []CSVParseError
}

type CSVParseError struct {
	Line   int
	ICCID  string
	Reason string
}

func ParseICCIDFromCSV(reader io.Reader) (*CSVParseResult, error) {
	csvReader := csv.NewReader(reader)
	csvReader.FieldsPerRecord = -1
	csvReader.TrimLeadingSpace = true

	result := &CSVParseResult{
		ICCIDs:      make([]string, 0),
		ParseErrors: make([]CSVParseError, 0),
	}

	lineNum := 0
	for {
		record, err := csvReader.Read()
		if err == io.EOF {
			break
		}
		lineNum++

		if err != nil {
			result.ParseErrors = append(result.ParseErrors, CSVParseError{
				Line:   lineNum,
				Reason: "CSV 解析错误: " + err.Error(),
			})
			continue
		}

		if len(record) == 0 {
			continue
		}

		iccid := strings.TrimSpace(record[0])
		if iccid == "" {
			continue
		}

		if lineNum == 1 && isHeader(iccid) {
			continue
		}

		result.TotalCount++
		result.ICCIDs = append(result.ICCIDs, iccid)
	}

	return result, nil
}

func isHeader(value string) bool {
	lower := strings.ToLower(value)
	return lower == "iccid" || lower == "卡号" || lower == "号码"
}