package api

import (
	"encoding/json"
	"nerd-monitor/internal/stats"
	"nerd-monitor/internal/store"
	"net/http"
)

// Handler manages HTTP requests.
type Handler struct {
	store *store.Store
}

// New creates a new API handler.
func New(s *store.Store) *Handler {
	return &Handler{store: s}
}

// ReportStats handles agent stats reports.
func (h *Handler) ReportStats(w http.ResponseWriter, r *http.Request) {
	agentID := r.URL.Query().Get("id")
	if agentID == "" {
		http.Error(w, "missing agent id", http.StatusBadRequest)
		return
	}

	var stat stats.Stats
	if err := json.NewDecoder(r.Body).Decode(&stat); err != nil {
		http.Error(w, "invalid request body", http.StatusBadRequest)
		return
	}

	h.store.UpdateAgent(agentID, &stat)
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]string{"status": "ok"})
}

// GetAgent returns stats for a single agent.
func (h *Handler) GetAgent(w http.ResponseWriter, r *http.Request) {
	agentID := r.URL.Query().Get("id")
	if agentID == "" {
		http.Error(w, "missing agent id", http.StatusBadRequest)
		return
	}

	agent := h.store.GetAgent(agentID)
	if agent == nil {
		http.Error(w, "agent not found", http.StatusNotFound)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(agent)
}

// ListAgents returns all agents.
func (h *Handler) ListAgents(w http.ResponseWriter, r *http.Request) {
	agents := h.store.GetAllAgents()
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(agents)
}

// DeleteAgent removes an agent.
func (h *Handler) DeleteAgent(w http.ResponseWriter, r *http.Request) {
	agentID := r.URL.Query().Get("id")
	if agentID == "" {
		http.Error(w, "missing agent id", http.StatusBadRequest)
		return
	}

	h.store.DeleteAgent(agentID)
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]string{"status": "deleted"})
}

// UpdateHostname updates the hostname for an agent.
func (h *Handler) UpdateHostname(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}

	agentID := r.PathValue("id")
	if agentID == "" {
		http.Error(w, "missing agent id", http.StatusBadRequest)
		return
	}

	hostname := r.FormValue("hostname")
	if hostname == "" {
		http.Error(w, "missing hostname", http.StatusBadRequest)
		return
	}

	err := h.store.UpdateHostname(agentID, hostname)
	if err != nil {
		http.Error(w, "agent not found", http.StatusNotFound)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(map[string]string{"status": "updated"})
}