// This file provides a Kong resolver that loads configuration from a TOML file.

// It is a lightly modified version of the kongtoml package.

//

// It checks if the ytt subcommand is used and if so, it uses the parent path to

// construct the key. This makes the configuration file more readable and ergonomic.

package main

import (

"io"

"strings"

"github.com/alecthomas/kong"

"github.com/pelletier/go-toml/v2"

)

func ConfLoader(r io.Reader) (kong.Resolver, error) {

var tree map[string]any

decoder := toml.NewDecoder(r)

if err := decoder.Decode(&tree); err != nil {

return nil, err

}

var filename string

if named, ok := r.(interface{ Name() string }); ok {

filename = named.Name()

}

return &ConfResolver{filename: filename, tree: tree}, nil

}

type ConfResolver struct {

filename string

tree map[string]any

}

func (r *ConfResolver) Resolve(kctx *kong.Context, parent *kong.Path, flag *kong.Flag) (interface{}, error) {

value, ok := r.findValue(parent, flag)

if !ok {

return nil, nil

}

return value, nil

}

func (r *ConfResolver) Validate(app *kong.Application) error {

// TODO: Validate the configuration maps to valid flags.

return nil

}

func (r *ConfResolver) findValue(parent *kong.Path, flag *kong.Flag) (any, bool) {

// Get parent path, converting to empty string if "ytt"

path := parent.Node().Path()

if path == "ytt" {

path = ""

}

keys := []string{

strings.ReplaceAll(path, " ", "-") + "-" + flag.Name,

flag.Name,

}

for _, key := range keys {

parts := strings.Split(key, "-")

if value, ok := r.findValueParts(parts[0], parts[1:], r.tree); ok {

return value, ok

}

}

return nil, false

}

func (r *ConfResolver) findValueParts(prefix string, suffix []string, tree map[string]any) (any, bool) {

if value, ok := tree[prefix]; ok {

if len(suffix) == 0 {

return value, true

}

if branch, ok := value.(map[string]any); ok {

return r.findValueParts(suffix[0], suffix[1:], branch)

}

} else if len(suffix) > 0 {

return r.findValueParts(prefix+"-"+suffix[0], suffix[1:], tree)

}

return nil, false

}