package cnf

import (
	lib "github.com/xdrm-brackets/nix-amer/internal/cnf/parser/nginx"
	"io"
	"strings"
)

type nginx struct {
	data   *lib.Line
	parsed bool
}

// ReadFrom implements io.ReaderFrom
func (d *nginx) ReadFrom(_reader io.Reader) (int64, error) {

	d.data = new(lib.Line)

	// 1. get nginx decoder
	decoder := lib.NewDecoder(_reader)
	err := decoder.Decode(d.data)
	if err != nil {
		return 0, err
	}

	d.parsed = true
	return 0, nil

}

// WriteTo implements io.WriterTo
func (d *nginx) WriteTo(_writer io.Writer) (int64, error) {
	encoder := lib.NewEncoder(_writer)
	return 0, encoder.Encode(d.data)
}

// browse returns the target of a dot-separated path (as an interface{} chain where the last is the target if found)
// if <create> is true, create if does not exist
func (d *nginx) browse(_path string, create ...bool) (*lib.Line, bool) {

	mustCreate := len(create) > 0 && create[0]

	// 1. extract path
	path := strings.Split(_path, ".")

	// 2. nothing
	if len(path) < 1 {
		return &lib.Line{}, true
	}

	// 3. init output chain
	current := d.data

	// 4. iterate over path / nested fields
	l := len(path)
	for i, field := range path {

		// 5. intermediary fields (sections)
		if i < l-1 {
			found := false
			for _, child := range current.Lines {
				if child.Type == lib.SECTION && len(child.Components) > 0 && child.Components[0] == field {
					found = true
					current = child
					break
				}
			}

			if found {
				continue
			}

			// create section
			if mustCreate {
				sec := &lib.Line{
					Type:       lib.SECTION,
					Components: []string{field},
					Lines:      make([]*lib.Line, 0),
				}
				current.Lines = append(current.Lines, sec)
				continue
			}

			// not found and not create
			return nil, false
		}

		// 6. last field (assignment)
		for _, child := range current.Lines {
			if child.Type == lib.ASSIGNMENT && len(child.Components) > 0 && child.Components[0] == field {
				return child, true
			}
		}

		// create assignment
		if mustCreate {
			assignment := &lib.Line{
				Type:       lib.ASSIGNMENT,
				Components: []string{field, ""},
				Lines:      nil,
			}
			current.Lines = append(current.Lines, assignment)
			return assignment, true
		}

		// not found and not create
		return nil, false

	}

	return nil, false
}

// Get returns the value of a dot-separated path, and if it exists
func (d *nginx) Get(_path string) (string, bool) {

	// 1. browse path
	last, found := d.browse(_path, true)
	if !found || len(last.Components) < 2 {
		return "", false
	}

	// 2. Get last field
	return last.Components[1], true

}

// Set the value of a dot-separated path, and creates it if not found
func (d *nginx) Set(_path, _value string) bool {

	// 1. browse path
	last, found := d.browse(_path, true)
	if !found || len(last.Components) < 2 {
		return false
	}

	// 2. Set value
	last.Components[1] = _value
	return true

}