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"
	// 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 {
	wg sync.WaitGroup

	finders                map[string]PeripheralFinder // The map of peripherals finders
	peripherals            []*Peripheral               // The current list of peripherals
	peripheralsScanTrigger chan struct{}               // Trigger the peripherals scans
}

// 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),
		peripherals:            make([]*Peripheral, 0),
		peripheralsScanTrigger: make(chan struct{}),
	}
}

// Start starts to find new peripheral events
func (h *Manager) Start(ctx context.Context) error {
	// Initialize all the finders and their callback functions
	h.RegisterFinder(NewFTDIFinder(3 * time.Second))
	h.RegisterFinder(NewOS2LFinder())
	h.RegisterFinder(NewMIDIFinder(3 * time.Second))

	for finderName, finder := range h.finders {
		err := finder.Initialize()
		if err != nil {
			log.Err(err).Str("file", "hardware").Str("finderName", finderName).Msg("unable to initialize finder")
			return err
		}
		finder.OnArrival(func(p PeripheralInfo) {
			runtime.EventsEmit(ctx, string(PeripheralArrival), p)
		})
		finder.OnRemoval(func(p PeripheralInfo) {
			runtime.EventsEmit(ctx, string(PeripheralRemoval), p)
		})
		err = finder.Start(ctx)
		if err != nil {
			log.Err(err).Str("file", "hardware").Str("finderName", finderName).Msg("unable to start finder")
			return err
		}
	}

	// Periodically scan all the finders
	h.wg.Add(1)
	go func() {
		defer h.wg.Done()
		for {
			select {
			case <-ctx.Done():
				return
			case <-h.peripheralsScanTrigger:
				for finderName, finder := range h.finders {
					log.Trace().Str("file", "hardware").Str("finderName", finderName).Msg("force a finder to scan peripherals")
					finder.ForceScan()
				}
			}
		}
	}()
	return nil
}

// 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")
}

// Scan scans all the peripherals for the registered finders
func (h *Manager) Scan() error {
	select {
	case h.peripheralsScanTrigger <- struct{}{}:
		return nil
	default:
		return fmt.Errorf("scan trigger not available (manager stopped?)")
	}
}

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

	// Closing trigger channel
	close(h.peripheralsScanTrigger)

	// 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 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
}