package protocol

import (
	"encoding/json"
	"errors"
	"fmt"
	"os"
)

// Protocol structure
type Protocol struct {
	Metadata      Meta
	Structure     []*Field
	DefaultValues []DefaultValues
	JavaScript    string
}

// ToJSON conversion
func (prot Protocol) ToJSON() string {
	data, err := json.MarshalIndent(prot, "", "  ")
	if err != nil {
		return ""
	}
	return string(data)
}

// NewProtocolStructure which is empty
func NewProtocolStructure() *Protocol {
	p := Protocol{}
	return &p
}

// AppendField to protocol
func (prot *Protocol) AppendField(field Field) int {
	i := len(prot.Structure)
	prot.Structure = append(prot.Structure, &field)
	return i + 1
}

// AppendFields to protocol
func (prot *Protocol) AppendFields(fields ...Field) {
	for _, e := range fields {
		prot.AppendField(e)
	}
}

// AddField to protocol
func (prot *Protocol) AddField(index int, field *Field) {
	if len(prot.Structure) == index {
		prot.AppendField(*field)
		return
	}
	ret := make([]*Field, 0)
	ret = append(ret, prot.Structure[:index]...)
	ret = append(ret, field)
	ret = append(ret, prot.Structure[index:]...)
	prot.Structure = ret
}

// UpdateFieldByName in the protocol
func (prot *Protocol) UpdateFieldByName(name string, field *Field) {
	var fnd int = -1
	for i, f := range prot.Structure {
		if f.Name == name {
			fnd = i
		}
	}
	if fnd != -1 {
		prot.Structure[fnd] = field
	}
}

// UpdateFieldByElement in the protocol
func (prot *Protocol) UpdateFieldByElement(element int, field *Field) {
	prot.Structure[element] = field
}

// RemoveFieldByName from the protocol
func (prot *Protocol) RemoveFieldByName(name string) error {
	element := -1
	for i, f := range prot.Structure {
		if f.Name == name {
			element = i
		}
	}
	if element == -1 {
		return errors.New("Element not found")
	}
	prot.RemoveFieldByElement(element)
	return nil
}

// RemoveFieldByElement from the protocol
func (prot *Protocol) RemoveFieldByElement(field int) {
	ret := make([]*Field, 0)
	for i, f := range prot.Structure {
		if i != field {
			fmt.Printf("appending %d, %s\n", i, f.ToJSON())
			ret = append(ret, f)
		}
	}
	prot.Structure = ret
}

// Load a protocol from path into the current reference
func (prot *Protocol) Load(path string) error {
	data, err := os.ReadFile(path)
	if err != nil {
		return err
	}
	err = json.Unmarshal(data, prot)
	return err
}

// Save a protocol at a path location
func (prot *Protocol) Save(path string) error {
	data, err := json.MarshalIndent(*prot, "", "  ")
	if err != nil {
		return err
	}
	err = os.WriteFile(path, data, 0644)
	return err
}

// LoadNew protocol from path
func LoadNew(path string) (*Protocol, error) {
	prot := NewProtocolStructure()
	err := prot.Load(path)
	return prot, err
}