package suggestions

import (
	"database/sql"
	"errors"
	"net/http"
	"strings"

	"github.com/go-chi/chi/v5"

	"gitea.parodia.dev/drwily/petal/internal/auth"
	"gitea.parodia.dev/drwily/petal/internal/httputil"
	"gitea.parodia.dev/drwily/petal/internal/llm"
)

type translateResponse struct {
	Translation string `json:"translation"`
}

// translate renders a suggestion's English explanation into Simplified Chinese
// for the Ask Petal bubble, so the ESL reader sees the "why" in her first
// language instead of a second copy of the same English text. The explanation is
// loaded server-side from the suggestion id (scoped to the local user) and never
// trusted from the client, mirroring chat (spec Note #10).
func (h *Handler) translate(w http.ResponseWriter, r *http.Request) {
	sugID := chi.URLParam(r, "id")

	var explanation, pairLang string
	err := h.DB.QueryRow(
		`SELECT s.explanation, COALESCE(u.pair_lang, '')
		   FROM suggestions s
		   JOIN documents d ON d.id = s.doc_id
		   JOIN users u ON u.id = d.user_id
		  WHERE s.id = ? AND d.user_id = ?`,
		sugID, auth.UserID(r.Context()),
	).Scan(&explanation, &pairLang)
	if errors.Is(err, sql.ErrNoRows) {
		httputil.ErrorJSON(w, http.StatusNotFound, "suggestion not found")
		return
	}
	if err != nil {
		httputil.ServerError(w, err)
		return
	}

	explanation = strings.TrimSpace(explanation)
	if explanation == "" {
		httputil.WriteJSON(w, http.StatusOK, translateResponse{Translation: ""})
		return
	}

	out, err := llm.RunTranslate(r.Context(), h.Client, explanation, llm.LangFor(pairLang))
	if err != nil {
		httputil.UpstreamError(w, "translate", err)
		return
	}

	httputil.WriteJSON(w, http.StatusOK, translateResponse{Translation: out})
}