package main

import (
	"database/sql"
	"encoding/json"
	"log"
	"net/http"
	"os"
	"strings"

	_ "github.com/lib/pq"
)

type Config struct {
	Port  string `json:"port"`
	DBUrl string `json:"db_url"`
}

func loadConfig() Config {
	cfg := Config{
		Port:  "8080",
		DBUrl: "postgres://monitor:monitorpassword@localhost:5432/vdimonitor?sslmode=disable",
	}

	file, err := os.Open("config.json")
	if err == nil {
		defer file.Close()
		decoder := json.NewDecoder(file)
		if err := decoder.Decode(&cfg); err != nil {
			log.Printf("Warning: Failed to parse config.json: %v", err)
		}
	}

	if envPort := os.Getenv("PORT"); envPort != "" {
		cfg.Port = envPort
	}
	if envDB := os.Getenv("DB_URL"); envDB != "" {
		cfg.DBUrl = envDB
	}

	return cfg
}

type MetricPayload struct {
	Hostname            string          `json:"hostname"`
	TotalCpuPercent     float64         `json:"total_cpu_percent"`
	TotalMemPercent     float64         `json:"total_mem_percent"`
	DpcInterruptPercent float64         `json:"dpc_interrupt_percent"`
	TopCpuProcesses     json.RawMessage `json:"top_cpu_processes"`
	TopMemProcesses     json.RawMessage `json:"top_mem_processes"`
	TopIoProcesses      json.RawMessage `json:"top_io_processes"`
	NetworkConnections  json.RawMessage `json:"network_connections"`
	HungProcesses       json.RawMessage `json:"hung_processes"`
}

var db *sql.DB

func main() {
	cfg := loadConfig()

	var err error
	db, err = sql.Open("postgres", cfg.DBUrl)
	if err != nil {
		log.Fatalf("Failed to connect to db: %v", err)
	}
	defer db.Close()

	http.HandleFunc("/api/metrics", handleMetrics)

	port := cfg.Port
	if !strings.HasPrefix(port, ":") {
		port = ":" + port
	}

	log.Printf("Server starting on %s\n", port)
	log.Fatal(http.ListenAndServe(port, nil))
}

func handleMetrics(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	var payload MetricPayload
	if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
		http.Error(w, "Bad request", http.StatusBadRequest)
		return
	}

	_, err := db.Exec(
		`INSERT INTO client_metrics 
		(hostname, total_cpu_percent, total_mem_percent, dpc_interrupt_percent, top_cpu_processes, top_mem_processes, top_io_processes, network_connections, hung_processes) 
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)`,
		payload.Hostname, payload.TotalCpuPercent, payload.TotalMemPercent, payload.DpcInterruptPercent, 
		payload.TopCpuProcesses, payload.TopMemProcesses, payload.TopIoProcesses, payload.NetworkConnections, payload.HungProcesses,
	)
	if err != nil {
		log.Printf("DB insert error: %v", err)
		http.Error(w, "Internal server error", http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusCreated)
}