package shortcutui

/*
#cgo pkg-config: gtk+-3.0
#include <stdlib.h>
int shortcut_ui_open(const char *title, const char **groups, const char **labels, const char **keys, int count);
*/
import "C"

import (
	"encoding/json"
	"errors"
	"io"
	"runtime"
	"unsafe"
)

type Row struct {
	Group string `json:"group"`
	Label string `json:"label"`
	Keys  string `json:"keys"`
}

type List struct {
	Title string `json:"title"`
	Rows  []Row  `json:"rows"`
}

// Run displays one read-only, keyboard accessible shortcut list in a child process.
func Run(reader io.Reader) error {
	var list List
	if err := json.NewDecoder(io.LimitReader(reader, 1<<20)).Decode(&list); err != nil {
		return err
	}
	if len(list.Rows) == 0 || len(list.Rows) > 512 {
		return errors.New("invalid shortcut list")
	}
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	title := C.CString(list.Title)
	defer C.free(unsafe.Pointer(title))
	groups := make([]*C.char, len(list.Rows))
	labels := make([]*C.char, len(list.Rows))
	keys := make([]*C.char, len(list.Rows))
	for i, row := range list.Rows {
		groups[i], labels[i], keys[i] = C.CString(row.Group), C.CString(row.Label), C.CString(row.Keys)
		defer C.free(unsafe.Pointer(groups[i]))
		defer C.free(unsafe.Pointer(labels[i]))
		defer C.free(unsafe.Pointer(keys[i]))
	}
	if C.shortcut_ui_open(title, (**C.char)(unsafe.Pointer(&groups[0])), (**C.char)(unsafe.Pointer(&labels[0])), (**C.char)(unsafe.Pointer(&keys[0])), C.int(len(list.Rows))) == 0 {
		return errors.New("could not open shortcut list window")
	}
	return nil
}