package prompt

import "text/template"

// CompiledTemplates is the immutable parsed template set for one captured
// prompt. Callers must not mutate its templates after handing it to a renderer.
type CompiledTemplates struct {
	Session  *template.Template
	Messages []*template.Template
}

// InputMetadata is the captured declaration metadata for one prompt input.
// Nil metadata pointers mean the corresponding field was absent or null.
type InputMetadata struct {
	Name        string
	Required    bool
	ContentType *string
	Description *string
}

// RequirementSnapshot provides the captured syntax and declarations needed
// for requirement inspection without reopening prompt resources.
type RequirementSnapshot struct {
	Templates CompiledTemplates
	Inputs    []InputMetadata
}

// TemplateLookup provides parsed templates for a captured prompt identity.
type TemplateLookup interface {
	GetCompiledTemplates(id, version string) (CompiledTemplates, bool)
}

// CompileTemplate checks static syntax with the same grammar and function
// names as rendering, without evaluating request inputs or variables.
func CompileTemplate(name, raw string) (*template.Template, error) {
	return parseTemplate(name, raw, template.FuncMap{
		"input": func(string) (string, error) { return "", nil },
	})
}

func parseTemplate(name, raw string, funcs template.FuncMap) (*template.Template, error) {
	return template.New(name).Funcs(funcs).Option("missingkey=error").Parse(raw)
}