package llm

import "strings"

// The pair language, as the prompts need to talk about it.
//
// Three of Petal's prompts name the writer's first language rather than merely
// being written in English: the collocation coach asks for a gloss in it, Ask
// Petal offers to answer in it, and the explanation translator renders into it.
// Before Phase 19 all three said "Simplified Chinese" outright, which made the
// zh pair the only one that could ever work.
//
// A Lang is not a translation of the prompt — the instructions stay in English,
// which is what the model follows best. It is the name the model should use for
// her language, plus the one word it should watch for when she writes in it.
type Lang struct {
	// Code matches users.pair_lang.
	Code string
	// Name is how the prompt refers to the language, spelled the way a model
	// recognises it. Regional precision matters here: "European Portuguese" is
	// not "Portuguese" to a model that has read far more pt-BR than pt-PT.
	Name string
	// Why asks the same thing she would ask in her own language. It goes into
	// the Ask Petal prompt as an example, so a model that answers only to
	// English "why" still recognises the question when she types it her way.
	Why string
}

// langs holds every pair Petal can currently be a partner in. A language with a
// frontend langpack but no entry here still works — it falls back to zh's
// behaviour of the prompts, which is wrong but not broken — so keep the two in
// step when a pair ships.
var langs = map[string]Lang{
	"zh":    {Code: "zh", Name: "Simplified Chinese (Mandarin)", Why: "为什么"},
	"pt-PT": {Code: "pt-PT", Name: "European Portuguese (pt-PT, never Brazilian Portuguese)", Why: "porquê"},
	"fr":    {Code: "fr", Name: "French", Why: "pourquoi"},
	"es":    {Code: "es", Name: "Spanish", Why: "por qué"},
}

// DefaultLang is the pair assumed when none is known — the column's default, and
// the only pair that existed before Phase 19.
var DefaultLang = langs["zh"]

// LangFor resolves a users.pair_lang value. An empty or unrecognised code falls
// back to the default rather than erroring: a prompt is not the place to
// discover a configuration problem, and the writing still has to be checked.
func LangFor(code string) Lang {
	if l, ok := langs[strings.TrimSpace(code)]; ok {
		return l
	}
	return DefaultLang
}