// NextNVR — MIT License
// Copyright (c) 2026 NextNVR Contributors
// SPDX-License-Identifier: MIT
//
// config.go — JSON configuration management. Zero external dependencies.
package main

import (
	"encoding/json"
	"fmt"
	"os"
)

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

type ServerConfig struct {
	Port       string `json:"port"`
	BindHost   string `json:"bind_host"`
	ViewerPort string `json:"viewer_port"`
}

type StorageConfig struct {
	RecordingsPath      string `json:"recordings_path"`
	RetentionDays       int    `json:"retention_days"`
	CleanupIntervalMins int    `json:"cleanup_interval_mins"`
}

type CameraConfig struct {
	ID          string `json:"id"`
	Name        string `json:"name"`
	IP          string `json:"ip"`
	Username    string `json:"username"`
	Password    string `json:"password"`
	ONVIFPort   int    `json:"onvif_port,string"`
	RTSPMain    string `json:"rtsp_main"`
	RTSPSub     string `json:"rtsp_sub"`
	Description string `json:"description"`
	Enabled     bool   `json:"enabled"`
	Record      bool   `json:"record"`
}

type Go2RTCConfig struct {
	Enabled bool   `json:"enabled"`
	Port    string `json:"port"`
	Binary  string `json:"binary"`
}

type AuthConfig struct {
	Enabled bool       `json:"enabled"`
	Master  UserConfig `json:"master"`
	Viewer  UserConfig `json:"viewer"`
}

type UserConfig struct {
	Username string `json:"username"`
	Password string `json:"password"`
	Enabled  bool   `json:"enabled"`
}

// 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",
			ViewerPort: ":8090",
		},
		Storage: StorageConfig{
			RecordingsPath:      "/home/master/nvr_data",
			RetentionDays:       7,
			CleanupIntervalMins: 60,
		},
		Auth: AuthConfig{
			Enabled: false,
			Viewer:  UserConfig{Enabled: true},
		},
		Go2RTC: Go2RTCConfig{
			Enabled: true,
			Port:    ":1984",
			Binary:  "/opt/nextnvr/go2rtc",
		},
	}
}

// LoadConfig reads and parses a JSON configuration file.
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 := json.Unmarshal(data, &cfg); err != nil {
		return cfg, fmt.Errorf("parsing config: %w", err)
	}

	return cfg, nil
}

// SaveConfig writes the configuration to a JSON file.
func SaveConfig(cfg Config, path string) error {
	data, err := json.MarshalIndent(&cfg, "", "  ")
	if err != nil {
		return fmt.Errorf("marshaling config: %w", err)
	}
	data = append(data, '\n')

	if err := os.WriteFile(path, data, 0600); err != nil {
		return fmt.Errorf("writing config: %w", err)
	}
	return nil
}