package fieldgroups

import (
	"strings"

	"pdf-wizard/internal/models"
)

// MultiLineHandler handles groups where multiple text fields form a single
// multi-line response. When the form is filled, the textarea value is split
// evenly across the individual fields.
type MultiLineHandler struct{}

func init() {
	Register(MultiLineHandler{})
}

func (MultiLineHandler) Type() string {
	return "multiline"
}

func (MultiLineHandler) Validate(fields []models.FormField, fieldValues map[int]string) error {
	return nil
}

func (h MultiLineHandler) ConvertToFillValues(fields []models.FormField, fieldValues map[int]string) map[int]string {
	result := make(map[int]string)

	// Collect all submitted values - they should all have the same combined text
	var combined string
	for _, f := range fields {
		if v, ok := fieldValues[f.ID]; ok {
			combined = v
			break
		}
	}

	if combined == "" {
		// No value submitted, return empty for all
		for _, f := range fields {
			result[f.ID] = ""
		}
		return result
	}

	// Split the combined value into lines
	lines := strings.Split(combined, "\n")

	// Distribute lines evenly across fields
	n := len(fields)
	if n == 0 {
		return result
	}

	linesPerField := len(lines) / n
	extra := len(lines) % n

	start := 0
	for _, f := range fields {
		count := linesPerField
		if extra > 0 {
			count++
			extra--
		}
		end := start + count
		if end > len(lines) {
			end = len(lines)
		}
		result[f.ID] = strings.Join(lines[start:end], "\n")
		start = end
	}

	return result
}