assignment.go

package model

import (
	"strings"
)

// Assignment represents an assignment between fields in a struct.
type Assignment interface {
	// String returns the string representation of the assignment.
	String() string
	// RetError returns whether the assignment returns an error value.
	RetError() bool
}

// SkipField indicates that the field is skipped due to a :skip notation.
type SkipField struct {
	LHS string // LHS is the left-hand side of the skipped field.
}

// String returns the string representation of the skip field assignment.
func (s SkipField) String() string {
	var sb strings.Builder
	sb.WriteString("// skip: ")
	sb.WriteString(s.LHS)
	sb.WriteString("\n")
	return sb.String()
}

// RetError always returns false for skip field assignments.
func (s SkipField) RetError() bool {
	return false
}

// NoMatchField indicates that the field is skipped while there was no matching fields or getters.
type NoMatchField struct {
	LHS string // LHS is the name of the field that doesn't match any fields or getters.
}

// String returns the string representation of the no match field assignment.
func (s NoMatchField) String() string {
	var sb strings.Builder
	sb.WriteString("// no match: ")
	sb.WriteString(s.LHS)
	sb.WriteString("\n")
	return sb.String()
}

// RetError always returns false for no match field assignments.
func (s NoMatchField) RetError() bool {
	return false
}

// SimpleField represents an RHS expression.
type SimpleField struct {
	LHS   string
	RHS   string
	Error bool
}

// String returns the string representation of the simple field assignment.
func (s SimpleField) String() string {
	var sb strings.Builder
	sb.WriteString(s.LHS)
	if s.Error {
		sb.WriteString(", err")
	}
	sb.WriteString(" = ")
	sb.WriteString(s.RHS)
	sb.WriteString("\n")
	return sb.String()
}

// RetError returns whether the assignment returns an error value.
func (s SimpleField) RetError() bool {
	return s.Error
}

// NestStruct represents a struct in a struct.
type NestStruct struct {
	InitExpr      string
	NullCheckExpr string
	Contents      []Assignment
}

// String returns the string representation of the nested struct assignment.
func (s NestStruct) String() string {
	var sb strings.Builder
	if s.NullCheckExpr != "" {
		sb.WriteString("if ")
		sb.WriteString(s.NullCheckExpr)
		sb.WriteString(" != nil {\n")
	}
	if s.InitExpr != "" {
		sb.WriteString(s.InitExpr)
		sb.WriteString("\n")
	}
	for _, content := range s.Contents {
		sb.WriteString(content.String())
	}
	if s.NullCheckExpr != "" {
		sb.WriteString("}\n")
	}
	return sb.String()
}

// RetError returns whether the assignment returns an error value.
func (s NestStruct) RetError() bool {
	return false
}

// SliceAssignment represents a slice assignment.
type SliceAssignment struct {
	LHS string
	RHS string
	Typ string
}

// String returns the string representation of the slice assignment.
func (c SliceAssignment) String() string {
	var sb strings.Builder
	sb.WriteString("if ")
	sb.WriteString(c.RHS)
	sb.WriteString(" != nil {\n")
	sb.WriteString(c.LHS)
	sb.WriteString(" = make(")
	sb.WriteString(c.Typ)
	sb.WriteString(", len(")
	sb.WriteString(c.RHS)
	sb.WriteString("))\ncopy(")
	sb.WriteString(c.LHS)
	sb.WriteString(", ")
	sb.WriteString(c.RHS)
	sb.WriteString(")\n}\n")
	return sb.String()
}

// RetError returns whether the assignment returns an error value.
func (c SliceAssignment) RetError() bool {
	return false
}

// SliceLoopAssignment represents a slice assignment with a loop.
type SliceLoopAssignment struct {
	LHS string
	RHS string
	Typ string
}

// String returns the string representation of the slice assignment with a loop.
func (c SliceLoopAssignment) String() string {
	var sb strings.Builder
	sb.WriteString("if ")
	sb.WriteString(c.RHS)
	sb.WriteString(" != nil {\n")
	sb.WriteString(c.LHS)
	sb.WriteString(" = make(")
	sb.WriteString(c.Typ)
	sb.WriteString(", len(")
	sb.WriteString(c.RHS)
	sb.WriteString("))\nfor i, e := range ")
	sb.WriteString(c.RHS)
	sb.WriteString("{\n")
	sb.WriteString(c.LHS)
	sb.WriteString("[i] = e\n}\n}\n")
	return sb.String()
}

// RetError returns whether the assignment returns an error value.
func (c SliceLoopAssignment) RetError() bool {
	return false
}

// SliceTypecastAssignment represents a slice assignment with a typecast.
type SliceTypecastAssignment struct {
	LHS  string
	RHS  string
	Typ  string
	Cast string
}

// String returns the string representation of the slice assignment with a typecast.
func (c SliceTypecastAssignment) String() string {
	var sb strings.Builder
	sb.WriteString("if ")
	sb.WriteString(c.RHS)
	sb.WriteString(" != nil {\n")
	sb.WriteString(c.LHS)
	sb.WriteString(" = make(")
	sb.WriteString(c.Typ)
	sb.WriteString(", len(")
	sb.WriteString(c.RHS)
	sb.WriteString("))\nfor i, e := range ")
	sb.WriteString(c.RHS)
	sb.WriteString("{\n")
	sb.WriteString(c.LHS)
	sb.WriteString("[i] = ")
	sb.WriteString(c.Cast)
	sb.WriteString("(e)\n}\n}\n")
	return sb.String()
}

// RetError returns whether the assignment returns an error value.
func (c SliceTypecastAssignment) RetError() bool {
	return false
}