// Package clients provides third-party printer integrations.
package clients

import (
	"context"
	"crypto/tls"
	"encoding/json"
	"fmt"
	"log/slog"
	"time"

	mqtt "github.com/eclipse/paho.mqtt.golang"
)

// MQTTClient wraps the Eclipse Paho MQTT client for printer telemetry.
type MQTTClient struct {
	client mqtt.Client
}

// MQTTConfig holds per-printer MQTT connection settings.
type MQTTConfig struct {
	BrokerHost  string
	BrokerPort  int
	TopicPrefix string
	TLSEnabled  bool
	ClientID    string
}

// BambuPrintStatus is the known Bambu Lab print-status payload shape.
type BambuPrintStatus struct {
	Print struct {
		GcodeFile       string  `json:"gcode_file,omitempty"`
		Stage           int     `json:"stage,omitempty"`
		SubTaskName     string  `json:"subtask_name,omitempty"`
		PrintType       string  `json:"print_type,omitempty"`
		FilamentUsedMm  float64 `json:"mc_percent,omitempty"` // placeholder; real telemetry varies
	} `json:"print,omitempty"`
}

// NewMQTTClient creates an MQTT client connected to the given broker.
func NewMQTTClient(cfg MQTTConfig) (*MQTTClient, error) {
	if cfg.BrokerPort == 0 {
		if cfg.TLSEnabled {
			cfg.BrokerPort = 8883
		} else {
			cfg.BrokerPort = 1883
		}
	}
	if cfg.ClientID == "" {
		cfg.ClientID = fmt.Sprintf("extrudex-%d", time.Now().Unix())
	}

	opts := mqtt.NewClientOptions().
		AddBroker(fmt.Sprintf("tcp://%s:%d", cfg.BrokerHost, cfg.BrokerPort)).
		SetClientID(cfg.ClientID).
		SetAutoReconnect(true).
		SetConnectTimeout(10 * time.Second).
		SetOrderMatters(false)

	if cfg.TLSEnabled {
		opts = opts.SetTLSConfig(&tls.Config{InsecureSkipVerify: false})
	}

	client := mqtt.NewClient(opts)
	token := client.Connect()
	if token.Wait() && token.Error() != nil {
		return nil, fmt.Errorf("mqtt connect failed: %w", token.Error())
	}

	slog.Info("mqtt client connected", "broker", cfg.BrokerHost, "port", cfg.BrokerPort, "tls", cfg.TLSEnabled)
	return &MQTTClient{client: client}, nil
}

// Subscribe registers a callback for messages matching topic.
func (c *MQTTClient) Subscribe(topic string, qos byte, callback func([]byte)) error {
	token := c.client.Subscribe(topic, qos, func(_ mqtt.Client, msg mqtt.Message) {
		callback(msg.Payload())
	})
	if token.Wait() && token.Error() != nil {
		return fmt.Errorf("mqtt subscribe failed: %w", token.Error())
	}
	slog.Info("mqtt subscribed", "topic", topic, "qos", qos)
	return nil
}

// Unsubscribe removes a subscription.
func (c *MQTTClient) Unsubscribe(topics ...string) error {
	token := c.client.Unsubscribe(topics...)
	if token.Wait() && token.Error() != nil {
		return fmt.Errorf("mqtt unsubscribe failed: %w", token.Error())
	}
	return nil
}

// Disconnect cleanly disconnects the MQTT client.
func (c *MQTTClient) Disconnect(quiesceMs uint) {
	c.client.Disconnect(quiesceMs)
}

// IsConnected returns whether the underlying client is connected.
func (c *MQTTClient) IsConnected() bool {
	return c.client.IsConnected()
}

// ParseBambuTelemetry attempts to parse a Bambu Lab telemetry JSON payload.
func ParseBambuTelemetry(payload []byte) (*BambuPrintStatus, error) {
	var msg BambuPrintStatus
	if err := json.Unmarshal(payload, &msg); err != nil {
		return nil, fmt.Errorf("parse bambu telemetry failed: %w", err)
	}
	return &msg, nil
}

// DefaultBambuTopics returns the default topic patterns for Bambu Lab printers.
func DefaultBambuTopics(topicPrefix string) []string {
	return []string{
		topicPrefix + "/report",
	}
}