package handler

import (
	"database/sql"
	"encoding/json"
	"net/http"
	"time"
)

// HealthHandler returns the service health status.
type HealthHandler struct {
	db       *sql.DB
	startedAt time.Time
	version  string
}

// NewHealthHandler creates a new health handler.
func NewHealthHandler(db *sql.DB, version string) *HealthHandler {
	return &HealthHandler{
		db:        db,
		startedAt: time.Now(),
		version:   version,
	}
}

type healthResponse struct {
	Status    string `json:"status"`
	Version   string `json:"version,omitempty"`
	Uptime    string `json:"uptime,omitempty"`
	Database  string `json:"database"`
	Timestamp string `json:"timestamp"`
}

// ServeHTTP handles GET /healthz
func (h *HealthHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	dbStatus := "ok"
	if err := h.db.Ping(); err != nil {
		dbStatus = "error: " + err.Error()
	}

	resp := healthResponse{
		Status:    "ok",
		Version:   h.version,
		Uptime:    time.Since(h.startedAt).Round(time.Second).String(),
		Database:  dbStatus,
		Timestamp: time.Now().UTC().Format(time.RFC3339),
	}

	if dbStatus != "ok" {
		resp.Status = "degraded"
	}

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