package main

import (
	"fmt"
	"io"
	"os"
	"os/user"
	"path"
	"path/filepath"
	"runtime"
	"slices"

	"github.com/kkyr/fig"
	log "github.com/sirupsen/logrus"
	"gopkg.in/natefinch/lumberjack.v2"
)

// Config is the root configuration: a set of Lutron devices and the control
// sources that drive them.
type Config struct {
	Log     *LogConfig      `fig:"log" yaml:"log"`
	Devices []*DeviceConfig `fig:"devices" yaml:"devices"`
	Sources []*SourceConfig `fig:"sources" yaml:"sources"`
}

// LogConfig controls log verbosity, format, and output destinations.
type LogConfig struct {
	// Limit the log output by the log level.
	Level string `fig:"level" yaml:"level" enum:"debug,info,warn,error" default:"info"`
	// How the log output should be formatted.
	Type string `fig:"type" yaml:"type" enum:"json,console" default:"console"`
	// The outputs the log should go to. `console` goes to stderr, a file path logs
	//  to that file, and `default-file` logs to /var/log/<name>.log (or beside the
	//  executable if that is not writable).
	Outputs []string `fig:"outputs" yaml:"outputs" default:"console"`
	// Maximum size of the log file in megabytes before it gets rotated.
	MaxSize int `fig:"max_size" yaml:"max_size" default:"1"`
	// Maximum number of backups to save.
	MaxBackups int `fig:"max_backups" yaml:"max_backups" default:"3"`
	// Maximum number of days to retain old log files.
	MaxAge int `fig:"max_age" yaml:"max_age" default:"0"`
	// Use local system time instead of UTC for rotated backup file names.
	LocalTime *bool `fig:"local_time" yaml:"local_time" default:"true"`
	// Whether rotated logs should be compressed.
	Compress *bool `fig:"compress" yaml:"compress" default:"true"`
}

// DeviceConfig describes one Lutron integration interface (e.g. a GRAFIK Eye QS
// reached through a QSE-CI-NWK-E) and how to connect to it.
type DeviceConfig struct {
	// Name referenced by sources to bind to this device.
	Name string `fig:"name" yaml:"name"`
	// Transport used to reach the device.
	Transport string `fig:"transport" yaml:"transport" enum:"serial,telnet" default:"serial"`

	Serial SerialConfig `fig:"serial" yaml:"serial"`
	Telnet TelnetConfig `fig:"telnet" yaml:"telnet"`

	// IntegrationID bound to the GRAFIK Eye main unit in Lutron's programming.
	IntegrationID int `fig:"integration_id" yaml:"integration_id" default:"1"`
	// Zones is the number of controllable zones on the model (max 24).
	Zones int `fig:"zones" yaml:"zones" default:"6"`
	// Fade sent with each level command; "00:00" means instant.
	Fade string `fig:"fade" yaml:"fade" default:"00:00"`

	// EnableComponent and DisableComponent are the GRAFIK Eye QS phantom-button
	//  component numbers that, when pressed, signal integration control is
	//  (re)enabled or disabled. These are application-specific (programmed on the
	//  unit) and are not standard scene buttons; a press is "~DEVICE,<id>,<component>,3".
	//  Both default to 0 (disabled): the signal is only acted on when a non-zero
	//  component is configured, so an unrelated button can't silently disable the
	//  bridge. Set them to match your unit's programming to enable the feature.
	EnableComponent  int `fig:"enable_component" yaml:"enable_component" default:"0"`
	DisableComponent int `fig:"disable_component" yaml:"disable_component" default:"0"`

	Monitoring  MonitoringConfig  `fig:"monitoring" yaml:"monitoring"`
	Reliability ReliabilityConfig `fig:"reliability" yaml:"reliability"`
}

// MonitoringConfig controls the #MONITORING commands sent on connect. The
// protocol advises enabling only the monitoring you need; by default we ensure
// zone-level and reply monitoring are on (so feedback works even over RS-232 or
// if the unit's programmed defaults were changed) plus scene monitoring when a
// scene source is attached.
type MonitoringConfig struct {
	// Manage enables the on-connect monitoring setup; set false to leave the
	//  unit's programmed monitoring untouched.
	Manage *bool `fig:"manage" yaml:"manage" default:"true"`
	// Enable lists extra monitoring type numbers to turn on.
	Enable []int `fig:"enable" yaml:"enable"`
	// Disable lists monitoring type numbers to turn off (e.g. to silence noise).
	Disable []int `fig:"disable" yaml:"disable"`
}

// MonitorForward selects which panel monitoring a source relays outward. The
// device enables the union of every source's requested types on connect, then
// each source filters the resulting "~" reports it forwards.
type MonitorForward struct {
	// Enable lists #MONITORING type numbers to request from the panel for this
	//  source (1 diagnostic, 2 event, 3 button, 4 LED, 5 zone, 8 scene, 16
	//  sequence, 17 HVAC, 18 mode; 255 requests all). Empty relays whatever the
	//  panel already reports without requesting extra types.
	Enable []int `fig:"enable" yaml:"enable"`
	// Families optionally restricts which "~" message families are forwarded
	//  (e.g. ["DEVICE","GROUP"]); empty forwards every family.
	Families []string `fig:"families" yaml:"families"`
}

// SerialConfig holds the serial-transport connection settings.
type SerialConfig struct {
	// Device path of the serial adapter (find yours with `ls -lah /dev/serial/by-id/`).
	Device string `fig:"device" yaml:"device"`
	// Baud must match the dipswitch on the QSE-CI-NWK-E.
	Baud int `fig:"baud" yaml:"baud" default:"115200"`
}

// TelnetConfig holds the telnet-transport connection settings. The QSE-CI-NWK-E
// prompts for an integration login; username/password are sent when prompted.
type TelnetConfig struct {
	// Address is host:port; port 23 is assumed when omitted.
	Address string `fig:"address" yaml:"address"`
	// Username sent at the "login:" prompt (the integration login, e.g. "nwk").
	Username string `fig:"username" yaml:"username"`
	// Password sent at the "password:" prompt, when one is presented.
	Password string `fig:"password" yaml:"password"`
}

// ReliabilityConfig tunes the connection supervision behavior.
type ReliabilityConfig struct {
	// RxTimeoutSec is how long the link may be silent (while writing) before the
	//  watchdog probes and ultimately reconnects.
	RxTimeoutSec int `fig:"rx_timeout_sec" yaml:"rx_timeout_sec" default:"60"`
	// WatchdogIntervalSec is the watchdog tick interval.
	WatchdogIntervalSec int `fig:"watchdog_interval_sec" yaml:"watchdog_interval_sec" default:"15"`
	// ReconnectBackoffMinSec is the initial reconnect backoff.
	ReconnectBackoffMinSec int `fig:"reconnect_backoff_min_sec" yaml:"reconnect_backoff_min_sec" default:"1"`
	// ReconnectBackoffMaxSec caps the reconnect backoff.
	ReconnectBackoffMaxSec int `fig:"reconnect_backoff_max_sec" yaml:"reconnect_backoff_max_sec" default:"30"`
	// SendAllIntervalSec is how often every zone level is resent to prevent drift;
	//  0 disables the periodic resend, sending zones only when a target changes.
	SendAllIntervalSec int `fig:"send_all_interval_sec" yaml:"send_all_interval_sec" default:"10"`
	// ResetCooldownSec rate-limits the #RESET,0 recovery when the NWK wedges.
	ResetCooldownSec int `fig:"reset_cooldown_sec" yaml:"reset_cooldown_sec" default:"10"`
}

// SourceConfig describes one control source that drives a device's zones.
type SourceConfig struct {
	// Name identifies the source in logs.
	Name string `fig:"name" yaml:"name"`
	// Type selects the source implementation.
	Type string `fig:"type" yaml:"type" enum:"mqtt,sacn,artnet,osc"`
	// Device is the target device name this source controls.
	Device string `fig:"device" yaml:"device"`
	// Priority arbitrates between sources; a higher-priority source that is active
	//  locks out lower-priority ones (e.g. a live DMX stream over MQTT).
	Priority int `fig:"priority" yaml:"priority" default:"0"`
	// HoldSec is how long after its last update a source stays "active" for the
	//  purpose of locking out lower-priority sources.
	HoldSec float64 `fig:"hold_sec" yaml:"hold_sec" default:"5"`
	// Fade overrides the zone fade time this source applies when setting levels
	//  (format "SS", "MM:SS", or "HH:MM:SS"). When empty, DMX sources (sacn/artnet)
	//  default to instant ("00:00") so the console owns the crossfade, and other
	//  sources use the device's configured fade.
	Fade string `fig:"fade" yaml:"fade"`

	MQTT   MQTTConfig   `fig:"mqtt" yaml:"mqtt"`
	SACN   SACNConfig   `fig:"sacn" yaml:"sacn"`
	ArtNet ArtNetConfig `fig:"artnet" yaml:"artnet"`
	OSC    OSCConfig    `fig:"osc" yaml:"osc"`
}

// OSCConfig holds settings for an OSC (Open Sound Control) source. The server
// listens for UDP messages whose address, under the configured prefix, selects an
// operation (zone level, raise/lower/stop, scene, shade, lock, sequence). See the
// example config for the address scheme.
type OSCConfig struct {
	// Listen is the host:port the OSC server binds.
	Listen string `fig:"listen" yaml:"listen" default:"0.0.0.0:9000"`
	// Prefix is the OSC address namespace this source responds under.
	Prefix string `fig:"prefix" yaml:"prefix" default:"/lutron"`
	// Monitor selects which panel monitoring this source streams out as OSC.
	Monitor MonitorForward `fig:"monitor" yaml:"monitor"`
	// StreamTo lists host:port destinations the monitoring feedback is sent to.
	//  Streaming is off when empty.
	StreamTo []string `fig:"stream_to" yaml:"stream_to"`
	// LevelAsFloat sends zone levels as a 0-1 float (matching the input level
	//  convention) when true; false sends a raw 0-255 integer. Defaults to true.
	LevelAsFloat *bool `fig:"level_as_float" yaml:"level_as_float" default:"true"`
}

// MQTTConfig holds settings for an MQTT control source, including the optional
// Home Assistant discovery announcement.
type MQTTConfig struct {
	// Broker hostname or IP of the MQTT broker.
	Broker string `fig:"broker" yaml:"broker"`
	// Port of the MQTT broker.
	Port int `fig:"port" yaml:"port" default:"1883"`
	// Topic is the base state topic; commands are received on <topic>/set.
	Topic string `fig:"topic" yaml:"topic"`
	// Username for MQTT authentication.
	Username string `fig:"username" yaml:"username"`
	// Password for MQTT authentication.
	Password string `fig:"password" yaml:"password"`
	// ClientID for the MQTT connection; auto-generated when empty.
	ClientID string `fig:"client_id" yaml:"client_id"`
	// Discovery publishes a Home Assistant MQTT discovery config when true.
	Discovery bool `fig:"discovery" yaml:"discovery"`
	// DiscoveryPrefix is the Home Assistant discovery topic prefix.
	DiscoveryPrefix string `fig:"discovery_prefix" yaml:"discovery_prefix" default:"homeassistant"`
	// DeviceName is the friendly name announced to Home Assistant.
	DeviceName string `fig:"device_name" yaml:"device_name" default:"Lutron"`
	// Scenes, when > 0, exposes a scene selector (1..Scenes) over MQTT and, with
	//  discovery, a Home Assistant select entity. Commands arrive on <topic>/scene/set
	//  and the active scene is published to <topic>/scene.
	Scenes int `fig:"scenes" yaml:"scenes" default:"0"`
	// Shades, when > 0, exposes that many shade columns (1-3) as Home Assistant
	//  cover entities (open/close/stop). Commands arrive on <topic>/shade/<n>/set.
	Shades int `fig:"shades" yaml:"shades" default:"0"`
	// ZoneRamp exposes raise/lower/stop buttons for each light's zones.
	ZoneRamp bool `fig:"zone_ramp" yaml:"zone_ramp"`
	// ZoneLock exposes a zone-lock switch (QS Standalone).
	ZoneLock bool `fig:"zone_lock" yaml:"zone_lock"`
	// SceneLock exposes a scene-lock switch (QS Standalone).
	SceneLock bool `fig:"scene_lock" yaml:"scene_lock"`
	// Sequence exposes a scene-sequence select (Off / Scenes 1-4 / Scenes 5-16).
	Sequence bool `fig:"sequence" yaml:"sequence"`
	// Lights defines the individual lights exposed by this source, each driving
	//  its own set of zones. When omitted, a single light is synthesized from the
	//  base topic and device_name driving every zone.
	Lights []MQTTLightConfig `fig:"lights" yaml:"lights"`
	// Monitor selects which panel monitoring this source publishes to MQTT.
	Monitor MonitorForward `fig:"monitor" yaml:"monitor"`
	// MonitorPrefix is the sub-topic monitoring is published under, i.e.
	//  <topic>/<MonitorPrefix>/<family>/...
	MonitorPrefix string `fig:"monitor_prefix" yaml:"monitor_prefix" default:"monitor"`
}

// MQTTLightConfig describes one Home Assistant light exposed by an MQTT source and
// the set of QSE zones it controls. The light's brightness drives every zone in
// the set; the first zone is mirrored back as the aggregate state.
type MQTTLightConfig struct {
	// Name is the friendly name announced to Home Assistant; defaults to the
	//  source's device_name when empty.
	Name string `fig:"name" yaml:"name"`
	// Topic is the base state topic for this light; commands arrive on <topic>/set.
	Topic string `fig:"topic" yaml:"topic"`
	// Zones lists the 1-indexed QSE zones this light controls together.
	Zones []int `fig:"zones" yaml:"zones"`
}

// SACNConfig holds settings for an sACN (E1.31) control source.
type SACNConfig struct {
	// Bind address for the receiver socket ("" binds all interfaces).
	Bind string `fig:"bind" yaml:"bind"`
	// Interface is the network interface name used for multicast (optional).
	Interface string `fig:"interface" yaml:"interface"`
	// Universe is the sACN universe to join.
	Universe uint16 `fig:"universe" yaml:"universe" default:"1"`

	DMXMap `fig:",squash"`
}

// ArtNetConfig holds settings for an Art-Net control source.
type ArtNetConfig struct {
	// Bind is the IP the Art-Net node listens on.
	Bind string `fig:"bind" yaml:"bind" default:"0.0.0.0"`
	// Net is the Art-Net Net (top 7 bits of the 15-bit port address).
	Net uint8 `fig:"net" yaml:"net" default:"0"`
	// SubNet is the high nibble of the low byte of the port address.
	SubNet uint8 `fig:"subnet" yaml:"subnet" default:"0"`
	// Universe is the low nibble of the low byte of the port address.
	Universe uint8 `fig:"universe" yaml:"universe" default:"0"`
	// TimeoutSec is how long the universe may be silent before the source is
	//  treated as lost: its zones black out and its arbitration lock is released.
	//  Art-Net senders may slow retransmission of an unchanged look to once every
	//  ~4 s, so the default leaves margin above that.
	TimeoutSec float64 `fig:"timeout_sec" yaml:"timeout_sec" default:"5"`

	DMXMap `fig:",squash"`
}

// DMXMap describes how a DMX universe's channels map to a device's zones and
// scenes. Use the sequential layout (start_address plus zone/scene counts) for
// the common case, or an explicit channels list for full control. When channels
// is set it takes precedence over the sequential layout.
type DMXMap struct {
	// StartAddress is the 0-indexed channel of the first zone in the sequential
	//  layout. Zones occupy start_address.. and scenes follow them.
	StartAddress int `fig:"start_address" yaml:"start_address" default:"0"`
	// Zones is the number of sequential zone channels (0 = the device's zone count).
	Zones int `fig:"zones" yaml:"zones" default:"0"`
	// Scenes, when > 0, adds one scene-select channel after the zones; its value
	//  (1..Scenes) selects the scene to trigger and 0 means no action.
	Scenes int `fig:"scenes" yaml:"scenes" default:"0"`
	// Channels is an explicit per-channel map; when set it replaces the sequential
	//  layout above.
	Channels []DMXChannelConfig `fig:"channels" yaml:"channels"`
}

// DMXChannelConfig maps one DMX channel to a zone level or scene selection.
type DMXChannelConfig struct {
	// Channel is the 1-indexed DMX address (1-512).
	Channel int `fig:"channel" yaml:"channel"`
	// Type selects what the channel controls: "zone" sets a zone level, "scene" is a
	//  scene-select channel whose value triggers the matching scene.
	Type string `fig:"type" yaml:"type" enum:"zone,scene"`
	// Zone is the target zone number for type "zone".
	Zone int `fig:"zone" yaml:"zone"`
}

// Apply configures the global logger from the log configuration.
func (l *LogConfig) Apply() {
	// Apply the level.
	switch l.Level {
	case "debug":
		log.SetLevel(log.DebugLevel)
	case "info":
		log.SetLevel(log.InfoLevel)
	case "warn":
		log.SetLevel(log.WarnLevel)
	default:
		log.SetLevel(log.ErrorLevel)
	}

	// Apply the formatter.
	switch l.Type {
	case "json":
		log.SetFormatter(&log.JSONFormatter{})
	default:
		log.SetFormatter(&log.TextFormatter{})
	}

	// Resolve and attach each configured output.
	var outputs []io.Writer
	for _, output := range l.Outputs {
		// Console output goes to stderr.
		if output == "console" {
			outputs = append(outputs, os.Stderr)
			continue
		}

		// Resolve the default file location when requested.
		if output == "default-file" {
			resolved, ok := defaultLogPath()
			if !ok {
				log.Println("Unable to find a writable log path to save log to.")
				continue
			}
			output = resolved
		}

		// Rotate the file output via lumberjack.
		outputs = append(outputs, &lumberjack.Logger{
			Filename:   output,
			MaxSize:    l.MaxSize,
			MaxBackups: l.MaxBackups,
			MaxAge:     l.MaxAge,
			LocalTime:  *l.LocalTime,
			Compress:   *l.Compress,
		})
	}

	if len(outputs) != 0 {
		log.SetOutput(io.MultiWriter(outputs...))
	}
}

// defaultLogPath returns a writable path for the `default-file` output, trying
// /var/log first and falling back to beside the executable.
func defaultLogPath() (string, bool) {
	logName := fmt.Sprintf("%s.log", serviceName)

	// On *nix, prefer /var/log when writable.
	if runtime.GOOS != "windows" {
		logPath := filepath.Join("/var/log", logName)
		if f, err := os.OpenFile(logPath, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644); err == nil {
			f.Close()
			return logPath, true
		}
	}

	// Otherwise fall back to the executable's directory.
	exe, err := os.Executable()
	if err != nil {
		return "", false
	}
	logPath := filepath.Join(filepath.Dir(exe), logName)
	if f, err := os.OpenFile(logPath, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644); err == nil {
		f.Close()
		return logPath, true
	}
	return "", false
}

// ReadConfig loads, validates, and applies the configuration.
func (a *App) ReadConfig() {
	usr, err := user.Current()
	if err != nil {
		log.Fatal(err)
	}

	// Configuration search paths.
	localConfig, _ := filepath.Abs("./config.yaml")
	homeDirConfig := filepath.Join(usr.HomeDir, ".config", serviceName, "config.yaml")
	etcConfig := filepath.Join("/etc", serviceName, "config.yaml")

	// Determine which configuration file to use.
	var configFile string
	if app.flags.ConfigPath != "" {
		if _, err := os.Stat(app.flags.ConfigPath); err == nil {
			configFile = app.flags.ConfigPath
		}
	}
	if configFile == "" {
		for _, candidate := range []string{localConfig, homeDirConfig, etcConfig} {
			if _, err := os.Stat(candidate); err == nil {
				configFile = candidate
				break
			}
		}
	}
	if configFile == "" {
		log.Fatal("Unable to find a configuration file.")
	}

	// Load the configuration file.
	config := &Config{Log: &LogConfig{}}
	filePath, fileName := path.Split(configFile)
	if filePath == "" {
		filePath = "."
	}
	err = fig.Load(config, fig.File(fileName), fig.Dirs(filePath))
	if err != nil {
		log.Fatalf("Error parsing configuration: %s", err)
	}

	// Validate cross-field constraints fig can't express in tags.
	if err := config.Validate(); err != nil {
		log.Fatalf("Invalid configuration: %s", err)
	}

	// The verbose flag forces debug-level logging and ensures the console output
	//  is present, overriding the configured log level so debug output is visible.
	if app.flags.Verbose {
		config.Log.Level = "debug"
		if !slices.Contains(config.Log.Outputs, "console") {
			config.Log.Outputs = append(config.Log.Outputs, "console")
		}
	}

	// Apply log configuration and store globally.
	config.Log.Apply()
	app.config = config
	log.Infof("Loaded configuration from %s", configFile)
}

// Validate checks structural constraints across the configuration.
func (c *Config) Validate() error {
	if len(c.Devices) == 0 {
		return fmt.Errorf("no devices configured")
	}

	// Validate devices and index them by name.
	devices := make(map[string]*DeviceConfig, len(c.Devices))
	for i, d := range c.Devices {
		if d.Name == "" {
			return fmt.Errorf("device %d: name is required", i)
		}
		if devices[d.Name] != nil {
			return fmt.Errorf("duplicate device name %q", d.Name)
		}
		devices[d.Name] = d

		switch d.Transport {
		case "serial":
			if d.Serial.Device == "" {
				return fmt.Errorf("device %q: serial.device is required", d.Name)
			}
		case "telnet":
			if d.Telnet.Address == "" {
				return fmt.Errorf("device %q: telnet.address is required", d.Name)
			}
		}

		if d.Zones < 1 || d.Zones > 24 {
			return fmt.Errorf("device %q: zones must be 1-24", d.Name)
		}
	}

	// Validate sources reference an existing device.
	for i, s := range c.Sources {
		if s.Name == "" {
			return fmt.Errorf("source %d: name is required", i)
		}
		dev := devices[s.Device]
		if dev == nil {
			return fmt.Errorf("source %q: unknown device %q", s.Name, s.Device)
		}
		if s.Type == "mqtt" {
			if s.MQTT.Broker == "" {
				return fmt.Errorf("source %q: mqtt.broker is required", s.Name)
			}
			// A base topic is needed for the synthesized single light and for the
			//  scene selector; per-light topics cover the multi-light case.
			if len(s.MQTT.Lights) == 0 && s.MQTT.Topic == "" {
				return fmt.Errorf("source %q: mqtt.topic is required", s.Name)
			}
			if s.MQTT.Scenes > 0 && s.MQTT.Topic == "" {
				return fmt.Errorf("source %q: mqtt.topic is required when scenes are enabled", s.Name)
			}
			if s.MQTT.Shades < 0 || s.MQTT.Shades > 3 {
				return fmt.Errorf("source %q: mqtt.shades must be 0-3", s.Name)
			}
			// The shade/lock/sequence controls are rooted on the base topic.
			if (s.MQTT.Shades > 0 || s.MQTT.ZoneLock || s.MQTT.SceneLock || s.MQTT.Sequence) && s.MQTT.Topic == "" {
				return fmt.Errorf("source %q: mqtt.topic is required for shade/lock/sequence controls", s.Name)
			}
			// Validate each configured light's topic and zone set.
			seen := make(map[string]bool, len(s.MQTT.Lights))
			for j, l := range s.MQTT.Lights {
				if l.Topic == "" {
					return fmt.Errorf("source %q: mqtt.lights[%d].topic is required", s.Name, j)
				}
				if seen[l.Topic] {
					return fmt.Errorf("source %q: duplicate mqtt light topic %q", s.Name, l.Topic)
				}
				seen[l.Topic] = true
				if len(l.Zones) == 0 {
					return fmt.Errorf("source %q: mqtt light %q controls no zones", s.Name, l.Topic)
				}
				for _, z := range l.Zones {
					if z < 1 || z > dev.Zones {
						return fmt.Errorf("source %q: mqtt light %q zone %d out of range 1-%d", s.Name, l.Topic, z, dev.Zones)
					}
				}
			}
		}
	}

	return nil
}