package hardware

import (
	"context"
	"errors"
	"fmt"
	goRuntime "runtime"
	"sync"
	"time"
	"unsafe"

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

/*
#include <stdlib.h>
#cgo LDFLAGS: -L${SRCDIR}/../build/bin -ldetectFTDI
#include "cpp/include/detectFTDIBridge.h"
*/
import "C"

// FTDIFinder manages all the FTDI peripherals
type FTDIFinder struct {
	wg sync.WaitGroup
	mu sync.Mutex

	saved    map[string]PeripheralInfo  // Peripherals saved in the project
	detected map[string]*FTDIPeripheral // Detected peripherals

	scanEvery time.Duration // Scans peripherals periodically

	onArrival func(p PeripheralInfo) // When a peripheral arrives
	onRemoval func(p PeripheralInfo) // When a peripheral goes away
}

// NewFTDIFinder creates a new FTDI finder
func NewFTDIFinder(scanEvery time.Duration) *FTDIFinder {
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder created")
	return &FTDIFinder{
		scanEvery: scanEvery,
		saved:     make(map[string]PeripheralInfo),
		detected:  make(map[string]*FTDIPeripheral),
	}
}

// OnArrival is the callback function when a new peripheral arrives
func (f *FTDIFinder) OnArrival(cb func(p PeripheralInfo)) {
	f.onArrival = cb
}

// OnRemoval i the callback when a peripheral goes away
func (f *FTDIFinder) OnRemoval(cb func(p PeripheralInfo)) {
	f.onRemoval = cb
}

// RegisterPeripheral registers a new peripheral
func (f *FTDIFinder) RegisterPeripheral(ctx context.Context, peripheralData PeripheralInfo) (string, error) {
	f.mu.Lock()
	defer f.mu.Unlock()

	f.saved[peripheralData.SerialNumber] = peripheralData

	// If already detected, connect it
	if peripheral, ok := f.detected[peripheralData.SerialNumber]; ok {
		f.wg.Add(1)
		go func() {
			defer f.wg.Done()
			runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralData, PeripheralStatusConnecting)
			err := peripheral.Connect(ctx)
			if err != nil {
				runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralData, PeripheralStatusDisconnected)
				log.Err(err).Str("file", "FTDIFinder").Str("peripheralSN", peripheralData.SerialNumber).Msg("unable to connect the peripheral")
				return
			}
			runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralData, PeripheralStatusDeactivated)
			// Peripheral connected, activate it
			err = peripheral.Activate(ctx)
			if err != nil {
				log.Err(err).Str("file", "FTDIFinder").Str("peripheralSN", peripheralData.SerialNumber).Msg("unable to activate the FTDI peripheral")
				return
			}
			runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralData, PeripheralStatusActivated)
		}()
	}

	// Emits the event in the hardware
	runtime.EventsEmit(ctx, "LOAD_PERIPHERAL", peripheralData)

	return peripheralData.SerialNumber, nil
}

// UnregisterPeripheral unregisters an existing peripheral
func (f *FTDIFinder) UnregisterPeripheral(ctx context.Context, peripheralData PeripheralInfo) error {
	f.mu.Lock()
	defer f.mu.Unlock()

	if peripheral, detected := f.detected[peripheralData.SerialNumber]; detected {
		// Deactivating peripheral
		err := peripheral.Deactivate(ctx)
		if err != nil {
			log.Err(err).Str("sn", peripheralData.SerialNumber).Msg("unable to deactivate the peripheral")
			return nil
		}
		runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralData, PeripheralStatusDeactivated)
		// Disconnecting peripheral
		err = peripheral.Disconnect()
		if err != nil {
			log.Err(err).Str("sn", peripheralData.SerialNumber).Msg("unable to disconnect the peripheral")
			return nil
		}
		runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralData, PeripheralStatusDisconnected)
	}
	delete(f.saved, peripheralData.SerialNumber)
	runtime.EventsEmit(ctx, "UNLOAD_PERIPHERAL", peripheralData)

	return nil
}

// Initialize initializes the FTDI finder
func (f *FTDIFinder) Initialize() error {
	// Check platform
	if goRuntime.GOOS != "windows" {
		log.Error().Str("file", "FTDIFinder").Str("platform", goRuntime.GOOS).Msg("FTDI finder not compatible with your platform")
		return fmt.Errorf("the FTDI finder is not compatible with your platform yet (%s)", goRuntime.GOOS)
	}
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder initialized")
	return nil
}

// Start starts the finder and search for peripherals
func (f *FTDIFinder) Start(ctx context.Context) error {
	f.wg.Add(1)
	go func() {
		ticker := time.NewTicker(f.scanEvery)
		defer ticker.Stop()
		defer f.wg.Done()

		for {
			select {
			case <-ctx.Done():
				return
			case <-ticker.C:
				// Scan the peripherals
				err := f.scanPeripherals(ctx)
				if err != nil {
					log.Err(err).Str("file", "FTDIFinder").Msg("unable to scan FTDI peripherals")
				}
			}
		}
	}()
	return nil
}

// ForceScan explicitly asks for scanning peripherals
func (f *FTDIFinder) ForceScan() {
	// select {
	// case f.scanChannel <- struct{}{}:
	// default:
	// 	// Ignore if the channel is full or if it is closed
	// }
}

// GetName returns the name of the driver
func (f *FTDIFinder) GetName() string {
	return "FTDI"
}

// GetPeripheralSettings gets the peripheral settings
func (f *FTDIFinder) GetPeripheralSettings(peripheralID string) (map[string]interface{}, error) {
	// Return the specified peripheral
	// peripheral, found := f.registeredPeripherals[peripheralID]
	// if !found {
	// 	log.Error().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("unable to get this peripheral from the FTDI finder")
	// 	return nil, fmt.Errorf("unable to found the peripheral")
	// }
	// log.Debug().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("peripheral found by the FTDI finder")
	// return peripheral.GetSettings(), nil
	return make(map[string]interface{}), nil
}

// SetPeripheralSettings sets the peripheral settings
func (f *FTDIFinder) SetPeripheralSettings(ctx context.Context, peripheralID string, settings map[string]any) error {
	// Return the specified peripheral
	// peripheral, found := f.registeredPeripherals[peripheralID]
	// if !found {
	// 	log.Error().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("unable to get this peripheral from the FTDI finder")
	// 	return fmt.Errorf("unable to found the peripheral")
	// }
	// log.Debug().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("peripheral found by the FTDI finder")
	// return peripheral.SetSettings(settings)
	return nil
}

// scanPeripherals scans the FTDI peripherals
func (f *FTDIFinder) scanPeripherals(ctx context.Context) error {
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI scan triggered")

	count := int(C.get_peripherals_number())

	log.Info().Int("number", count).Msg("number of FTDI devices connected")

	// Allocating C array
	size := C.size_t(count) * C.size_t(unsafe.Sizeof(C.FTDIPeripheralC{}))
	devicesPtr := C.malloc(size)
	defer C.free(devicesPtr)

	devices := (*[1 << 20]C.FTDIPeripheralC)(devicesPtr)[:count:count]

	C.get_ftdi_devices((*C.FTDIPeripheralC)(devicesPtr), C.int(count))

	currentMap := make(map[string]PeripheralInfo)

	for i := 0; i < count; i++ {
		d := devices[i]

		sn := C.GoString(d.serialNumber)
		desc := C.GoString(d.description)
		// isOpen := d.isOpen != 0

		currentMap[sn] = PeripheralInfo{
			SerialNumber: sn,
			Name:         desc,
			// IsOpen:       isOpen,
			ProtocolName: "FTDI",
		}

		// Free C memory
		C.free_ftdi_device(&d)
	}

	log.Info().Any("peripherals", currentMap).Msg("available FTDI peripherals")

	// Detect arrivals
	for sn, peripheralData := range currentMap {
		if _, known := f.detected[sn]; !known {
			peripheral := NewFTDIPeripheral(peripheralData)
			f.detected[sn] = peripheral

			if f.onArrival != nil {
				f.onArrival(peripheralData)
			}
			log.Info().Str("sn", sn).Str("name", peripheralData.Name).Msg("[FTDI] New peripheral detected")

			// Disconnected by default
			runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), peripheralData, PeripheralStatusDisconnected)

			// If the peripheral is saved in the project => connect
			if _, saved := f.saved[sn]; saved {
				f.wg.Add(1)
				go func(p PeripheralInfo) {
					defer f.wg.Done()
					runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), p, PeripheralStatusConnecting)
					err := peripheral.Connect(ctx)
					if err != nil {
						runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), p, PeripheralStatusDisconnected)
						log.Err(err).Str("sn", p.SerialNumber).Msg("unable to connect the FTDI peripheral")
						return
					}
					runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), p, PeripheralStatusDeactivated)
					err = peripheral.Activate(ctx)
					if err != nil {
						log.Err(err).Str("sn", p.SerialNumber).Msg("unable to activate the FTDI peripheral")
						return
					}
					runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), p, PeripheralStatusActivated)
				}(peripheralData)
			}
		}
	}

	// Detect removals
	for sn, oldPeripheral := range f.detected {
		if _, still := currentMap[sn]; !still {

			// Properly clean the DMX device
			err := oldPeripheral.Deactivate(ctx)
			if err != nil {
				log.Err(err).Str("sn", sn).Msg("unable to deactivate the FTDI peripheral after disconnection")
			}
			runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), oldPeripheral.GetInfo(), PeripheralStatusDeactivated)
			err = oldPeripheral.Disconnect()
			if err != nil {
				log.Err(err).Str("sn", sn).Msg("unable to disconnect the FTDI peripheral after disconnection")
			}
			runtime.EventsEmit(ctx, string(PeripheralStatusUpdated), oldPeripheral.GetInfo(), PeripheralStatusDisconnected)

			// Delete it from the detected list
			delete(f.detected, sn)
			log.Info().Str("sn", sn).Str("name", oldPeripheral.GetInfo().Name).Msg("[FTDI] peripheral removed")

			// Execute the removal callback
			if f.onRemoval != nil {
				f.onRemoval(oldPeripheral.GetInfo())
			}
		}
	}
	return nil
}

// WaitStop stops the finder
func (f *FTDIFinder) WaitStop() error {
	log.Trace().Str("file", "FTDIFinder").Msg("stopping the FTDI finder...")

	// Close the channel
	// close(f.scanChannel)

	// Wait for all the peripherals to close
	log.Trace().Str("file", "FTDIFinder").Msg("closing all FTDI peripherals")
	var errs []error
	for registeredPeripheralSN, registeredPeripheral := range f.detected {
		err := registeredPeripheral.WaitStop()
		if err != nil {
			errs = append(errs, fmt.Errorf("%s: %w", registeredPeripheralSN, err))
		}
	}

	// Wait for goroutines to stop
	f.wg.Wait()

	// Returning errors
	if len(errs) > 0 {
		return errors.Join(errs...)
	}
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder stopped")
	return nil
}