// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later

package notificationui

/*
#cgo pkg-config: gtk+-3.0
#include <stdlib.h>
#include "native.h"
*/
import "C"

import (
	"bufio"
	"context"
	"encoding/json"
	"errors"
	"io"
	"runtime"
	"time"
	"unsafe"
)

// Run owns all GTK calls on one OS thread. The parent supplies a private pipe;
// no widget invokes speech directly.
func Run(ctx context.Context, input io.Reader, output io.Writer) error {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()
	updates := make(chan Response, 1)
	errorsIn := make(chan error, 1)
	go func() {
		scanner := bufio.NewScanner(input)
		scanner.Buffer(make([]byte, 4096), 1024*1024)
		for scanner.Scan() {
			var response Response
			if err := json.Unmarshal(scanner.Bytes(), &response); err != nil {
				errorsIn <- err
				return
			}
			select {
			case updates <- response:
			case <-ctx.Done():
				return
			}
		}
		errorsIn <- scanner.Err()
	}()

	var initial Response
	select {
	case initial = <-updates:
	case err := <-errorsIn:
		if errors.Is(err, io.EOF) {
			return nil
		}
		return err
	case <-ctx.Done():
		return ctx.Err()
	}
	title := C.CString(initial.Title)
	defer C.free(unsafe.Pointer(title))
	messageHeader := C.CString("Notifications")
	defer C.free(unsafe.Pointer(messageHeader))
	receivedHeader := C.CString("Received")
	defer C.free(unsafe.Pointer(receivedHeader))
	if C.notification_list_init(title, messageHeader, receivedHeader) == 0 {
		return errors.New("cannot open the notification list on this display")
	}
	defer C.notification_list_close()
	apply(initial)
	C.notification_list_show()

	encoder := json.NewEncoder(output)
	ticker := time.NewTicker(10 * time.Millisecond)
	defer ticker.Stop()
	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		case err := <-errorsIn:
			if errors.Is(err, io.EOF) {
				return nil
			}
			return err
		case response := <-updates:
			if response.Close {
				return nil
			}
			if response.Present {
				C.notification_list_present()
				continue
			}
			apply(response)
		case <-ticker.C:
			C.notification_list_iterate()
			switch C.notification_list_action() {
			case 1:
				if C.notification_list_copy() != 0 {
					if err := encoder.Encode(Request{Copy: true}); err != nil {
						return err
					}
				}
			case 2:
				selection := C.GoString(C.notification_list_selected_id())
				row := int(C.notification_list_selected_row())
				if err := encoder.Encode(Request{Dismiss: true, Selection: selection, Row: &row}); err != nil {
					return err
				}
			case 3:
				if err := encoder.Encode(Request{Clear: true}); err != nil {
					return err
				}
			case 4:
				return nil
			case 5:
				selection := C.GoString(C.notification_list_selected_id())
				row := int(C.notification_list_selected_row())
				if err := encoder.Encode(Request{Selection: selection, Row: &row}); err != nil {
					return err
				}
			case 6:
				action := C.GoString(C.notification_list_selected_action())
				selection := C.GoString(C.notification_list_selected_id())
				row := int(C.notification_list_selected_row())
				if err := encoder.Encode(Request{Action: action, Selection: selection, Row: &row}); err != nil {
					return err
				}
			}
		}
	}
}

func apply(response Response) {
	messages := make([]*C.char, len(response.Entries))
	received := make([]*C.char, len(response.Entries))
	identifiers := make([]*C.char, len(response.Entries))
	for index, entry := range response.Entries {
		identifiers[index] = C.CString(entry.ID)
		messages[index] = C.CString(entry.Message)
		received[index] = C.CString(entry.Received)
	}
	defer func() {
		for _, value := range messages {
			C.free(unsafe.Pointer(value))
		}
		for _, value := range received {
			C.free(unsafe.Pointer(value))
		}
		for _, value := range identifiers {
			C.free(unsafe.Pointer(value))
		}
	}()

	selectedID := C.CString(response.Selected)
	defer C.free(unsafe.Pointer(selectedID))
	var selectedEntry Entry
	for _, entry := range response.Entries {
		if entry.ID == response.Selected {
			selectedEntry = entry
			break
		}
	}
	actionKeys := make([]*C.char, len(selectedEntry.Actions))
	actionLabels := make([]*C.char, len(selectedEntry.Actions))
	for index, action := range selectedEntry.Actions {
		actionKeys[index] = C.CString(action.Key)
		actionLabels[index] = C.CString(action.Label)
	}
	defer func() {
		for _, value := range actionKeys {
			C.free(unsafe.Pointer(value))
		}
		for _, value := range actionLabels {
			C.free(unsafe.Pointer(value))
		}
	}()

	C.notification_list_set_entries(
		cStringArray(messages), cStringArray(received), C.int(len(response.Entries)),
		cStringArray(identifiers), selectedID, cBoolean(selectedEntry.CanControl),
		cStringArray(actionKeys), cStringArray(actionLabels), C.int(len(selectedEntry.Actions)),
	)
}

func cStringArray(values []*C.char) **C.char {
	if len(values) == 0 {
		return nil
	}
	return (**C.char)(unsafe.Pointer(&values[0]))
}

func cBoolean(value bool) C.int {
	if value {
		return 1
	}
	return 0
}