package httpapi

import (
	"encoding/json"
	"errors"
	"log"
	"net/http"

	"github.com/allai/allai-backend/internal/app"
)

type Handler struct {
	service *app.Service
	logger  *log.Logger
}

func (h *Handler) health(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	_ = json.NewEncoder(w).Encode(map[string]string{"status": "ok"})
}

func (h *Handler) listModels(w http.ResponseWriter, r *http.Request) {
	models, err := h.service.Models(r.Context())
	if err != nil {
		h.writeError(w, http.StatusInternalServerError, err)
		return
	}

	h.writeJSON(w, http.StatusOK, models)
}

func (h *Handler) generate(w http.ResponseWriter, r *http.Request) {
	var payload app.GenerationRequest
	if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
		h.writeError(w, http.StatusBadRequest, errors.New("invalid JSON payload"))
		return
	}

	resp, err := h.service.Generate(r.Context(), payload)
	if err != nil {
		h.writeError(w, http.StatusBadRequest, err)
		return
	}

	h.writeJSON(w, http.StatusAccepted, resp)
}

func (h *Handler) writeJSON(w http.ResponseWriter, status int, payload any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)

	if err := json.NewEncoder(w).Encode(payload); err != nil {
		h.logger.Printf("response encode failed: %v", err)
	}
}

func (h *Handler) writeError(w http.ResponseWriter, status int, err error) {
	h.logger.Printf("request error: %v", err)
	h.writeJSON(w, status, map[string]string{
		"error": err.Error(),
	})
}

func middleware(next http.Handler, logger *log.Logger) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		logger.Printf("%s %s", r.Method, r.URL.Path)
		next.ServeHTTP(w, r)
	})
}