// NextNVR v0.1.0 — Configuration management
// Handles config.yaml parsing with sensible defaults
package main

import (
	"fmt"
	"os"
	"path/filepath"

	"gopkg.in/yaml.v3"
)

// Config represents the top-level application configuration.
type Config struct {
	Server  ServerConfig   `yaml:"server" json:"server"`
	Storage StorageConfig  `yaml:"storage" json:"storage"`
	Cameras []CameraConfig `yaml:"cameras" json:"cameras"`
	Go2RTC  Go2RTCConfig   `yaml:"go2rtc" json:"go2rtc"`
}

// ServerConfig holds HTTP server settings.
type ServerConfig struct {
	Port     string `yaml:"port"`
	BindHost string `yaml:"bind_host"`
}

// StorageConfig holds recording and retention settings.
type StorageConfig struct {
	RecordingsPath      string `yaml:"recordings_path"`
	RetentionDays       int    `yaml:"retention_days"`
	CleanupIntervalMins int    `yaml:"cleanup_interval_mins"`
}

// CameraConfig represents a single camera's configuration.
type CameraConfig struct {
	ID          string `yaml:"id" json:"id"`
	Name        string `yaml:"name" json:"name"`
	IP          string `yaml:"ip" json:"ip"`
	Username    string `yaml:"username" json:"username"`
	Password    string `yaml:"password" json:"password"`
	ONVIFPort   int    `yaml:"onvif_port" json:"onvif_port"`
	RTSPMain    string `yaml:"rtsp_main" json:"rtsp_main"`
	RTSPSub     string `yaml:"rtsp_sub" json:"rtsp_sub"`
	Description string `yaml:"description" json:"description"`
	Enabled     bool   `yaml:"enabled" json:"enabled"`
	Record      bool   `yaml:"record" json:"record"`
}

// Go2RTCConfig holds go2rtc child process settings.
type Go2RTCConfig struct {
	Enabled bool   `yaml:"enabled"`
	Port    string `yaml:"port"`
	Binary  string `yaml:"binary"`
}

// APIResponse wraps all JSON API responses.
type APIResponse struct {
	Success bool        `json:"success"`
	Data    interface{} `json:"data,omitempty"`
	Error   string      `json:"error,omitempty"`
}

// CameraStatus extends CameraConfig with runtime information.
type CameraStatus struct {
	CameraConfig
	Online  bool   `json:"online"`
	Uptime  string `json:"uptime"`
	Streams int    `json:"streams"`
}

// DefaultConfig returns a Config with sensible defaults.
func DefaultConfig() Config {
	return Config{
		Server: ServerConfig{
			Port:     ":8080",
			BindHost: "0.0.0.0",
		},
		Storage: StorageConfig{
			RecordingsPath:      "/mnt/recordings",
			RetentionDays:       18,
			CleanupIntervalMins: 60,
		},
		Go2RTC: Go2RTCConfig{
			Enabled: true,
			Port:    ":1984",
			Binary:  "go2rtc",
		},
	}
}

// LoadConfig reads and parses a YAML configuration file.
// If the file does not exist, it returns DefaultConfig().
func LoadConfig(path string) (Config, error) {
	cfg := DefaultConfig()

	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			return cfg, fmt.Errorf("config file not found: %s", path)
		}
		return cfg, fmt.Errorf("reading config: %w", err)
	}

	if err := yaml.Unmarshal(data, &cfg); err != nil {
		return cfg, fmt.Errorf("parsing config: %w", err)
	}

	// Apply path defaults relative to config file location.
	configDir := filepath.Dir(path)
	if cfg.Storage.RecordingsPath == "" {
		cfg.Storage.RecordingsPath = "/mnt/recordings"
	}
	_ = configDir // reserved for relative path resolution

	return cfg, nil
}

// SaveConfig writes the configuration to a YAML file.
func SaveConfig(cfg Config, path string) error {
	data, err := yaml.Marshal(&cfg)
	if err != nil {
		return fmt.Errorf("marshaling config: %w", err)
	}

	header := []byte("# NextNVR Configuration\n# Generated by NextNVR setup\n\n")
	out := append(header, data...)

	if err := os.WriteFile(path, out, 0644); err != nil {
		return fmt.Errorf("writing config: %w", err)
	}
	return nil
}