// SPDX-License-Identifier: MIT
/*
 * User Input
 *
 * Collects user input from libinput, transforms it (partially into
 * more flutter compatible forms), and calls configured handler callbacks.
 *
 * Copyright (c) 2023, Hannes Winkler <hanneswinkler2000@web.de>
 */

#ifndef _FLUTTERPI_SRC_USER_INPUT_H
#define _FLUTTERPI_SRC_USER_INPUT_H

#include <flutter_embedder.h>
#include <xkbcommon/xkbcommon.h>

#include "plugins/raw_keyboard.h"
#include "util/asserts.h"
#include "util/collection.h"
#include "util/geometry.h"

#define MAX_COLLECTED_FLUTTER_POINTER_EVENTS 64

typedef void (*flutter_pointer_event_callback_t)(void *userdata, const FlutterPointerEvent *events, size_t n_events);

typedef void (*utf8_character_callback_t)(void *userdata, uint8_t *character);

typedef void (*xkb_keysym_callback_t)(void *userdata, xkb_keysym_t keysym);

// clang-format off
typedef void (*gtk_keyevent_callback_t)(
    void *userdata,
    uint32_t unicode_scalar_values,
    uint32_t key_code,
    uint32_t scan_code,
    uint32_t modifiers,
    bool is_down
);
// clang-format on

typedef void (*set_cursor_enabled_callback_t)(void *userdata, bool enabled);

typedef void (*move_cursor_callback_t)(void *userdata, struct vec2f delta);

// clang-format off
typedef void (*keyevent_callback_t)(
    void *userdata,
    uint64_t timestamp_us,
    xkb_keycode_t xkb_keycode,
    xkb_keysym_t xkb_keysym,
    uint32_t plain_codepoint,
    key_modifiers_t modifiers,
    const char *text,
    bool is_down,
    bool is_repeat
);
// clang-format on

struct user_input_interface {
    flutter_pointer_event_callback_t on_flutter_pointer_event;
    utf8_character_callback_t on_utf8_character;
    xkb_keysym_callback_t on_xkb_keysym;
    gtk_keyevent_callback_t on_gtk_keyevent;
    set_cursor_enabled_callback_t on_set_cursor_enabled;
    move_cursor_callback_t on_move_cursor;
    int (*open)(const char *path, int flags, void *userdata);
    void (*close)(int fd, void *userdata);
    void (*on_switch_vt)(void *userdata, int vt);
    keyevent_callback_t on_key_event;
};

struct user_input;

/**
 * @brief Create a new user input instance. Will try to load the default keyboard config from /etc/default/keyboard
 * and create a udev-backed libinput instance.
 */
struct user_input *user_input_new(
    const struct user_input_interface *interface,
    void *userdata,
    const struct mat3f *display_to_view_transform,
    const struct mat3f *view_to_display_transform,
    unsigned int display_width,
    unsigned int display_height
);

/**
 * @brief Destroy this user input instance and free all allocated memory. This will not remove any input devices
 * added to flutter and won't invoke any callbacks in the user input interface at all.
 */
void user_input_destroy(struct user_input *input);

/**
 * @brief Set a 3x3 matrix and display width / height so user_input can transform any device coordinates into
 * proper flutter view coordinates. (For example to account for a rotated display)
 * Will also transform absolute & relative mouse movements.
 *
 * @param display_to_view_transform will be copied internally.
 */
void user_input_set_transform(
    struct user_input *input,
    const struct mat3f *display_to_view_transform,
    const struct mat3f *view_to_display_transform,
    unsigned int display_width,
    unsigned int display_height
);

/**
 * @brief Returns a filedescriptor used for input event notification. The returned
 * filedescriptor should be listened to with EPOLLIN | EPOLLRDHUP | EPOLLPRI or equivalent.
 * When the fd becomes ready, @ref user_input_on_fd_ready should be called not long after it
 * became ready. (libinput somehow relies on that)
 */
int user_input_get_fd(struct user_input *input);

/**
 * @brief Should be called when the fd returned by @ref user_input_get_fd becomes ready.
 * The user_input_interface callbacks will be called inside this function.
 */
int user_input_on_fd_ready(struct user_input *input);

void user_input_suspend(struct user_input *input);

int user_input_resume(struct user_input *input);

#endif  // _FLUTTERPI_SRC_USER_INPUT_H