package handler

import (
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/prabhupadasays/spsays-bff/internal/repository"
	"github.com/prabhupadasays/spsays-bff/pkg/response"
)

type GlossaryHandler struct {
	repo *repository.GlossaryRepo
}

func NewGlossaryHandler(repo *repository.GlossaryRepo) *GlossaryHandler {
	return &GlossaryHandler{repo: repo}
}

// List returns all glossary entries sorted by term.
// GET /glossary
func (h *GlossaryHandler) List(w http.ResponseWriter, r *http.Request) {
	docs, err := h.repo.GetAll(r.Context())
	if err != nil {
		response.Error(w, http.StatusInternalServerError, "failed to fetch glossary")
		return
	}
	response.JSON(w, http.StatusOK, docs)
}

// GetByTerm returns a single glossary entry by exact term match.
// GET /glossary/term/{term}
func (h *GlossaryHandler) GetByTerm(w http.ResponseWriter, r *http.Request) {
	term := chi.URLParam(r, "term")
	doc, err := h.repo.GetByTerm(r.Context(), term)
	if err != nil {
		response.Error(w, http.StatusInternalServerError, "failed to fetch term")
		return
	}
	if doc == nil {
		response.Error(w, http.StatusNotFound, "term not found")
		return
	}
	response.JSON(w, http.StatusOK, doc)
}

// GetByLetter returns all glossary entries whose term starts with the given
// base letter (including diacritical variants like Ā→A, Ś→S, etc.).
// GET /glossary/letter/{letter}
func (h *GlossaryHandler) GetByLetter(w http.ResponseWriter, r *http.Request) {
	letter := chi.URLParam(r, "letter")
	if len(letter) != 1 {
		response.Error(w, http.StatusBadRequest, "letter must be a single character")
		return
	}

	docs, err := h.repo.GetByLetter(r.Context(), letter)
	if err != nil {
		response.Error(w, http.StatusInternalServerError, "failed to fetch glossary entries")
		return
	}
	if docs == nil {
		docs = []repository.GlossaryEntryDoc{}
	}
	response.JSON(w, http.StatusOK, docs)
}

// GetTermsByLetter returns lightweight term summaries (no definitions) for a
// given base letter. Used for sidebar listing.
// GET /glossary/letter/{letter}/terms
func (h *GlossaryHandler) GetTermsByLetter(w http.ResponseWriter, r *http.Request) {
	letter := chi.URLParam(r, "letter")
	if len(letter) != 1 {
		response.Error(w, http.StatusBadRequest, "letter must be a single character")
		return
	}

	docs, err := h.repo.GetTermsByLetter(r.Context(), letter)
	if err != nil {
		response.Error(w, http.StatusInternalServerError, "failed to fetch terms")
		return
	}
	if docs == nil {
		docs = []repository.GlossaryTermSummary{}
	}
	response.JSON(w, http.StatusOK, docs)
}

// GetLetterCounts returns the count of glossary entries per base letter.
// GET /glossary/letters
func (h *GlossaryHandler) GetLetterCounts(w http.ResponseWriter, r *http.Request) {
	counts, err := h.repo.GetLetterCounts(r.Context())
	if err != nil {
		response.Error(w, http.StatusInternalServerError, "failed to fetch letter counts")
		return
	}
	response.JSON(w, http.StatusOK, counts)
}