package systemdconfig

import (
	"fmt"
	"strings"
)

type Field struct {
	key     string // key as output to file (can be commented out)
	value   string // value for a key in the section, must have associated key if set
	comment string // in-line comment if key is present, comment line if not
}

// Gets the key for the field
func (field *Field) GetKey() string {
	return field.key
}

// Returns if the field has a key
func (field *Field) HasKey() bool {
	return field.GetKey() != ""
}

// Commented out the fields key, if uncommented
func (field *Field) CommentKey() {
	if field.KeyIsCommented() {
		return
	}
	field.key = "#" + field.GetKey()
}

// Uncomments the fields key, if commented
func (field *Field) UncommentKey() {
	if !field.KeyIsCommented() {
		return
	}
	field.key = strings.TrimSpace(field.GetKey()[1:])
}

// Returns if the key is commented out
func (field *Field) KeyIsCommented() bool {
	return isCommented(field.GetKey())
}

// Gets the value for the field
func (field *Field) GetValue() string {
	return field.value
}

// Sets the value for the field
func (field *Field) SetValue(value string) error {
	if !valueIsValid(value) {
		return &SyntaxError{value, errValueSyntax}
	}
	if strings.HasSuffix(value, "\\") {
		return &UnsupportedError{value, errMultiLineValuesUnsupported}
	}
	field.value = value
	return nil
}

// Removes the value from the field, if it exists
func (field *Field) RemoveValue() {
	field.value = ""
}

// Returns if the field has a value set
func (field *Field) HasValue() bool {
	return field.GetValue() != ""
}

// Gets the comment string for the field
func (field *Field) GetComment() string {
	return field.comment
}

// Sets the comment string for the field
func (field *Field) SetComment(comment string) {
	if !isCommented(comment) {
		comment = "# " + comment
	}
	field.comment = comment
}

// Removes the comment from the field, if it exists
func (field *Field) RemoveComment() {
	field.comment = ""
}

// Returns if a field has a comment
func (field *Field) HasComment() bool {
	return field.GetComment() != ""
}

// Returns if the line is a comment, i.e. comment with no key:value
func (field *Field) IsCommentLine() bool {
	return !field.HasKey() && !field.HasValue() && field.HasComment()
}

// Returns if the line is empty
func (field *Field) IsEmptyLine() bool {
	return !field.HasKey() && !field.HasValue() && !field.HasComment()
}

// Gets the string line output to the file for a field
func (field *Field) ToFileLine() string {
	if field.IsEmptyLine() {
		return ""
	} else if field.IsCommentLine() {
		return field.GetComment()
	} else if field.HasComment() {
		return fmt.Sprintf("%s=%s %s", field.GetKey(), field.GetValue(), field.GetComment())
	}
	return fmt.Sprintf("%s=%s", field.GetKey(), field.GetValue())
}