package hardware

import (
	"context"
	"errors"
	"fmt"
	"sync"
	"time"

	"github.com/rs/zerolog/log"
	"github.com/wailsapp/wails/v2/pkg/runtime"
)

// PeripheralEvent is trigger by the finders when the scan is complete
type PeripheralEvent string

// PeripheralStatus is the peripheral status (DISCONNECTED => CONNECTING => DEACTIVATED => ACTIVATED)
type PeripheralStatus string

const (
	// PeripheralArrival is triggerd when a peripheral has been connected to the system
	PeripheralArrival PeripheralEvent = "PERIPHERAL_ARRIVAL"
	// PeripheralRemoval is triggered when a peripheral has been disconnected from the system
	PeripheralRemoval PeripheralEvent = "PERIPHERAL_REMOVAL"
	// PeripheralLoad is triggered when a peripheral is added to the project
	PeripheralLoad PeripheralEvent = "PERIPHERAL_LOAD"
	// PeripheralUnload is triggered when a peripheral is removed from the project
	PeripheralUnload PeripheralEvent = "PERIPHERAL_UNLOAD"
	// PeripheralStatusUpdated is triggered when a peripheral status has been updated (disconnected - connecting - deactivated - activated)
	PeripheralStatusUpdated PeripheralEvent = "PERIPHERAL_STATUS"
	// PeripheralEventEmitted is triggered when a peripheral event is emitted
	PeripheralEventEmitted PeripheralEvent = "PERIPHERAL_EVENT_EMITTED"
	// PeripheralStatusDisconnected : peripheral is now disconnected
	PeripheralStatusDisconnected PeripheralStatus = "PERIPHERAL_DISCONNECTED"
	// PeripheralStatusConnecting : peripheral is now connecting
	PeripheralStatusConnecting PeripheralStatus = "PERIPHERAL_CONNECTING"
	// PeripheralStatusDeactivated : peripheral is now deactivated
	PeripheralStatusDeactivated PeripheralStatus = "PERIPHERAL_DEACTIVATED"
	// PeripheralStatusActivated : peripheral is now activated
	PeripheralStatusActivated PeripheralStatus = "PERIPHERAL_ACTIVATED"
)

// Manager is the class who manages the hardware
type Manager struct {
	mu sync.Mutex
	wg sync.WaitGroup

	finders             map[string]PeripheralFinder // The map of peripherals finders
	DetectedPeripherals map[string]Peripheral       // The current list of peripherals
	SavedPeripherals    map[string]PeripheralInfo   // The list of stored peripherals
}

// NewManager creates a new hardware manager
func NewManager() *Manager {
	log.Trace().Str("package", "hardware").Msg("Hardware instance created")
	return &Manager{
		finders:             make(map[string]PeripheralFinder),
		DetectedPeripherals: make(map[string]Peripheral, 0),
		SavedPeripherals:    make(map[string]PeripheralInfo, 0),
	}
}

// RegisterPeripheral registers a new peripheral
func (h *Manager) RegisterPeripheral(ctx context.Context, peripheralInfo PeripheralInfo) (string, error) {
	h.mu.Lock()
	defer h.mu.Unlock()

	// Create the peripheral from its finder (if needed)
	if finder, found := h.finders[peripheralInfo.ProtocolName]; found {
		var err error
		peripheralInfo, err = finder.Create(ctx, peripheralInfo)
		if err != nil {
			return "", err
		}
	}

	// Do not save if the peripheral doesn't have a S/N
	if peripheralInfo.SerialNumber == "" {
		return "", fmt.Errorf("serial number is empty for this peripheral")
	}

	h.SavedPeripherals[peripheralInfo.SerialNumber] = peripheralInfo

	runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralInfo, PeripheralStatusDisconnected)

	// If already detected, connect it
	if peripheral, ok := h.DetectedPeripherals[peripheralInfo.SerialNumber]; ok {
		h.wg.Add(1)
		go func() {
			defer h.wg.Done()
			err := peripheral.Connect(ctx)
			if err != nil {
				log.Err(err).Str("file", "FTDIFinder").Str("peripheralSN", peripheralInfo.SerialNumber).Msg("unable to connect the peripheral")
				return
			}
			// Peripheral connected, activate it
			err = peripheral.Activate(ctx)
			if err != nil {
				log.Err(err).Str("file", "FTDIFinder").Str("peripheralSN", peripheralInfo.SerialNumber).Msg("unable to activate the FTDI peripheral")
				return
			}
		}()
	}

	// Emits the event in the hardware
	runtime.EventsEmit(ctx, string(PeripheralLoad), peripheralInfo)

	return peripheralInfo.SerialNumber, nil
}

// UnregisterPeripheral unregisters an existing peripheral
func (h *Manager) UnregisterPeripheral(ctx context.Context, peripheralInfo PeripheralInfo) error {
	h.mu.Lock()
	defer h.mu.Unlock()

	if peripheral, detected := h.DetectedPeripherals[peripheralInfo.SerialNumber]; detected {
		// Deactivating peripheral
		err := peripheral.Deactivate(ctx)
		if err != nil {
			log.Err(err).Str("sn", peripheralInfo.SerialNumber).Msg("unable to deactivate the peripheral")
			return nil
		}
		// Disconnecting peripheral
		err = peripheral.Disconnect(ctx)
		if err != nil {
			log.Err(err).Str("sn", peripheralInfo.SerialNumber).Msg("unable to disconnect the peripheral")
			return nil
		}
		// Remove the peripheral from its finder (if needed)
		if finder, found := h.finders[peripheralInfo.ProtocolName]; found {
			err = finder.Remove(ctx, peripheral)
			if err != nil {
				return err
			}
		}
	}
	delete(h.SavedPeripherals, peripheralInfo.SerialNumber)
	runtime.EventsEmit(ctx, string(PeripheralUnload), peripheralInfo)

	return nil
}

// GetPeripheralSettings gets the peripheral settings
func (h *Manager) GetPeripheralSettings(peripheralSN string) (map[string]any, error) {
	// Return the specified peripheral
	peripheral, found := h.DetectedPeripherals[peripheralSN]
	if !found {
		// Peripheral not detected, return the last settings saved
		if savedPeripheral, isFound := h.SavedPeripherals[peripheralSN]; isFound {
			return savedPeripheral.Settings, nil
		}
		return nil, fmt.Errorf("unable to found the peripheral")
	}
	return peripheral.GetSettings(), nil
}

// SetPeripheralSettings sets the peripheral settings
func (h *Manager) SetPeripheralSettings(ctx context.Context, peripheralSN string, settings map[string]any) error {
	peripheral, found := h.DetectedPeripherals[peripheralSN]
	if !found {
		return fmt.Errorf("unable to found the FTDI peripheral")
	}
	return peripheral.SetSettings(ctx, settings)
}

// Start starts to find new peripheral events
func (h *Manager) Start(ctx context.Context) error {

	// Register all the finders to use as hardware scanners
	h.RegisterFinder(NewFTDIFinder(3 * time.Second))
	h.RegisterFinder(NewOS2LFinder())
	h.RegisterFinder(NewMIDIFinder(3 * time.Second))

	for finderName, finder := range h.finders {

		// Initialize the finder
		err := finder.Initialize()
		if err != nil {
			log.Err(err).Str("file", "hardware").Str("finderName", finderName).Msg("unable to initialize finder")
			return err
		}

		// Set callback functions
		finder.OnArrival(h.OnPeripheralArrival)
		finder.OnRemoval(h.OnPeripheralRemoval)

		// Start the finder
		err = finder.Start(ctx)
		if err != nil {
			log.Err(err).Str("file", "hardware").Str("finderName", finderName).Msg("unable to start finder")
			return err
		}
	}
	return nil
}

// OnPeripheralArrival is called when a peripheral arrives in the system
func (h *Manager) OnPeripheralArrival(ctx context.Context, peripheral Peripheral) {
	// Add the peripheral to the detected hardware
	h.DetectedPeripherals[peripheral.GetInfo().SerialNumber] = peripheral

	// If the peripheral is saved in the project, connect it
	if _, saved := h.SavedPeripherals[peripheral.GetInfo().SerialNumber]; saved {
		h.wg.Add(1)
		go func(p Peripheral) {
			defer h.wg.Done()
			err := p.Connect(ctx)
			if err != nil {
				log.Err(err).Str("sn", p.GetInfo().SerialNumber).Msg("unable to connect the FTDI peripheral")
				return
			}
			err = p.Activate(ctx)
			if err != nil {
				log.Err(err).Str("sn", p.GetInfo().SerialNumber).Msg("unable to activate the FTDI peripheral")
				return
			}
		}(peripheral)
	}

	// TODO: Update the Peripheral reference in the corresponding devices

	runtime.EventsEmit(ctx, string(PeripheralArrival), peripheral.GetInfo())
}

// OnPeripheralRemoval is called when a peripheral exits the system
func (h *Manager) OnPeripheralRemoval(ctx context.Context, peripheral Peripheral) {
	// Properly deactivating and disconnecting the peripheral
	h.wg.Add(1)
	go func(p Peripheral) {
		defer h.wg.Done()
		err := p.Deactivate(ctx)
		if err != nil {
			log.Err(err).Str("sn", p.GetInfo().SerialNumber).Msg("unable to deactivate peripheral after disconnection")
		}
		err = p.Disconnect(ctx)
		if err != nil {
			log.Err(err).Str("sn", p.GetInfo().SerialNumber).Msg("unable to disconnect the peripheral after disconnection")
		}
	}(peripheral)

	// Remove the peripheral from the hardware
	delete(h.DetectedPeripherals, peripheral.GetInfo().SerialNumber)

	// TODO: Update the Peripheral reference in the corresponding devices
	runtime.EventsEmit(ctx, string(PeripheralRemoval), peripheral.GetInfo())
}

// GetFinder returns a register finder
func (h *Manager) GetFinder(finderName string) (PeripheralFinder, error) {
	finder, exists := h.finders[finderName]
	if !exists {
		log.Error().Str("file", "hardware").Str("finderName", finderName).Msg("unable to get the finder")
		return nil, fmt.Errorf("unable to locate the '%s' finder", finderName)
	}
	log.Debug().Str("file", "hardware").Str("finderName", finderName).Msg("got finder")
	return finder, nil
}

// RegisterFinder registers a new peripherals finder
func (h *Manager) RegisterFinder(finder PeripheralFinder) {
	h.finders[finder.GetName()] = finder
	log.Info().Str("file", "hardware").Str("finderName", finder.GetName()).Msg("finder registered")
}

// WaitStop stops the hardware manager
func (h *Manager) WaitStop() error {
	log.Trace().Str("file", "hardware").Msg("closing the hardware manager")

	// Stop each finder
	var errs []error
	for name, f := range h.finders {
		if err := f.WaitStop(); err != nil {
			errs = append(errs, fmt.Errorf("%s: %w", name, err))
		}
	}

	// Wait for all the peripherals to close
	log.Trace().Str("file", "MIDIFinder").Msg("closing all MIDI peripherals")
	for registeredPeripheralSN, registeredPeripheral := range h.DetectedPeripherals {
		err := registeredPeripheral.WaitStop()
		if err != nil {
			errs = append(errs, fmt.Errorf("%s: %w", registeredPeripheralSN, err))
		}
	}

	// Wait for goroutines to finish
	h.wg.Wait()

	// Returning errors
	if len(errs) > 0 {
		return errors.Join(errs...)
	}
	log.Info().Str("file", "hardware").Msg("hardware manager stopped")

	return nil
}