u-tpl/internal/context.go

package internal

import (
	"reflect"
	"strings"
)

type Context struct {
	vars map[string]any
}

func NewContext(vars map[string]any) *Context {
	return &Context{vars: vars}
}

func (c *Context) Get(path string) (any, bool) {
	if c.vars == nil {
		return nil, false
	}
	return resolvePath(c.vars, path)
}

func resolvePath(current any, path string) (any, bool) {
	for seg := range strings.SplitSeq(path, ".") {
		if current == nil {
			return nil, false
		}
		switch v := current.(type) {
		case map[string]any:
			var ok bool
			current, ok = v[seg]
			if !ok {
				return nil, false
			}
		default:
			val := reflect.ValueOf(current)
			for val.Kind() == reflect.Pointer {
				val = val.Elem()
			}
			if val.Kind() != reflect.Struct {
				return nil, false
			}
			field := val.FieldByName(seg)
			if !field.IsValid() {
				field = findFieldIgnoreCase(val, seg)
			}
			if !field.IsValid() {
				return nil, false
			}
			current = field.Interface()
		}
	}
	return current, true
}

func findFieldIgnoreCase(v reflect.Value, name string) reflect.Value {
	typ := v.Type()
	for i := range typ.NumField() {
		f := typ.Field(i)
		if !f.IsExported() {
			continue
		}
		if strings.EqualFold(f.Name, name) {
			return v.Field(i)
		}
	}
	return reflect.Value{}
}