#include <assert.h>
#include <linux/input-event-codes.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <unistd.h>
#include <wayland-server-core.h>
#include <wlr/interfaces/wlr_keyboard.h>
#include <wlr/util/log.h>
#include "interfaces/wlr_input_device.h"
#include "types/wlr_keyboard.h"
#include "util/set.h"
#include "util/shm.h"
#include "util/time.h"

struct wlr_keyboard *wlr_keyboard_from_input_device(
		struct wlr_input_device *input_device) {
	assert(input_device->type == WLR_INPUT_DEVICE_KEYBOARD);
	return wl_container_of(input_device, (struct wlr_keyboard *)NULL, base);
}

void keyboard_led_update(struct wlr_keyboard *keyboard) {
	if (keyboard->xkb_state == NULL) {
		return;
	}

	uint32_t leds = 0;
	for (uint32_t i = 0; i < WLR_LED_COUNT; ++i) {
		if (xkb_state_led_index_is_active(keyboard->xkb_state,
				keyboard->led_indexes[i])) {
			leds |= (1 << i);
		}
	}
	wlr_keyboard_led_update(keyboard, leds);
}

/**
 * Update the modifier state of the wlr-keyboard. Returns true if the modifier
 * state changed.
 */
bool keyboard_modifier_update(struct wlr_keyboard *keyboard) {
	if (keyboard->xkb_state == NULL) {
		return false;
	}

	xkb_mod_mask_t depressed = xkb_state_serialize_mods(keyboard->xkb_state,
		XKB_STATE_MODS_DEPRESSED);
	xkb_mod_mask_t latched = xkb_state_serialize_mods(keyboard->xkb_state,
		XKB_STATE_MODS_LATCHED);
	xkb_mod_mask_t locked = xkb_state_serialize_mods(keyboard->xkb_state,
		XKB_STATE_MODS_LOCKED);
	xkb_layout_index_t group = xkb_state_serialize_layout(keyboard->xkb_state,
		XKB_STATE_LAYOUT_EFFECTIVE);
	if (depressed == keyboard->modifiers.depressed &&
			latched == keyboard->modifiers.latched &&
			locked == keyboard->modifiers.locked &&
			group == keyboard->modifiers.group) {
		return false;
	}

	keyboard->modifiers.depressed = depressed;
	keyboard->modifiers.latched = latched;
	keyboard->modifiers.locked = locked;
	keyboard->modifiers.group = group;

	return true;
}

void keyboard_key_update(struct wlr_keyboard *keyboard,
		struct wlr_keyboard_key_event *event) {
	if (event->state == WL_KEYBOARD_KEY_STATE_PRESSED) {
		set_add(keyboard->keycodes, &keyboard->num_keycodes,
			WLR_KEYBOARD_KEYS_CAP, event->keycode);
	}
	if (event->state == WL_KEYBOARD_KEY_STATE_RELEASED) {
		set_remove(keyboard->keycodes, &keyboard->num_keycodes,
			WLR_KEYBOARD_KEYS_CAP, event->keycode);
	}

	assert(keyboard->num_keycodes <= WLR_KEYBOARD_KEYS_CAP);
}

void wlr_keyboard_notify_modifiers(struct wlr_keyboard *keyboard,
		uint32_t mods_depressed, uint32_t mods_latched, uint32_t mods_locked,
		uint32_t group) {
	if (keyboard->xkb_state == NULL) {
		return;
	}
	xkb_state_update_mask(keyboard->xkb_state, mods_depressed, mods_latched,
		mods_locked, 0, 0, group);

	bool updated = keyboard_modifier_update(keyboard);
	if (updated) {
		wl_signal_emit_mutable(&keyboard->events.modifiers, keyboard);
	}

	keyboard_led_update(keyboard);
}

void wlr_keyboard_notify_key(struct wlr_keyboard *keyboard,
		struct wlr_keyboard_key_event *event) {
	keyboard_key_update(keyboard, event);
	wl_signal_emit_mutable(&keyboard->events.key, event);

	if (keyboard->xkb_state == NULL) {
		return;
	}

	if (event->update_state) {
		uint32_t keycode = event->keycode + 8;
		xkb_state_update_key(keyboard->xkb_state, keycode,
			event->state == WL_KEYBOARD_KEY_STATE_PRESSED ? XKB_KEY_DOWN : XKB_KEY_UP);
	}

	bool updated = keyboard_modifier_update(keyboard);
	if (updated) {
		wl_signal_emit_mutable(&keyboard->events.modifiers, keyboard);
	}

	keyboard_led_update(keyboard);
}

void wlr_keyboard_init(struct wlr_keyboard *kb,
		const struct wlr_keyboard_impl *impl, const char *name) {
	*kb = (struct wlr_keyboard){
		.impl = impl,
		.keymap_fd = -1,

		// Sane defaults
		.repeat_info.rate = 25,
		.repeat_info.delay = 600,
	};
	wlr_input_device_init(&kb->base, WLR_INPUT_DEVICE_KEYBOARD, name);

	wl_signal_init(&kb->events.key);
	wl_signal_init(&kb->events.modifiers);
	wl_signal_init(&kb->events.keymap);
	wl_signal_init(&kb->events.repeat_info);
}

static void keyboard_unset_keymap(struct wlr_keyboard *kb) {
	xkb_keymap_unref(kb->keymap);
	kb->keymap = NULL;
	xkb_state_unref(kb->xkb_state);
	kb->xkb_state = NULL;
	free(kb->keymap_string);
	kb->keymap_string = NULL;
	kb->keymap_size = 0;
	if (kb->keymap_fd >= 0) {
		close(kb->keymap_fd);
	}
	kb->keymap_fd = -1;
}

void wlr_keyboard_finish(struct wlr_keyboard *kb) {
	/* Release pressed keys */
	int64_t time_msec = get_current_time_msec();
	while (kb->num_keycodes > 0) {
		struct wlr_keyboard_key_event event = {
			.time_msec = time_msec,
			.keycode = kb->keycodes[kb->num_keycodes - 1],
			.update_state = false,
			.state = WL_KEYBOARD_KEY_STATE_RELEASED,
		};
		wlr_keyboard_notify_key(kb, &event);  // updates num_keycodes
	}

	wlr_input_device_finish(&kb->base);

	keyboard_unset_keymap(kb);
}

void wlr_keyboard_led_update(struct wlr_keyboard *kb, uint32_t leds) {
	if (kb->leds == leds) {
		return;
	}

	kb->leds = leds;

	if (kb->impl && kb->impl->led_update) {
		kb->impl->led_update(kb, leds);
	}
}

bool wlr_keyboard_set_keymap(struct wlr_keyboard *kb, struct xkb_keymap *keymap) {
	if (keymap == NULL) {
		keyboard_unset_keymap(kb);
		wl_signal_emit_mutable(&kb->events.keymap, kb);
		return true;
	}

	struct xkb_state *xkb_state = xkb_state_new(keymap);
	if (xkb_state == NULL) {
		wlr_log(WLR_ERROR, "Failed to create XKB state");
		return false;
	}

	char *keymap_str = xkb_keymap_get_as_string(keymap, XKB_KEYMAP_FORMAT_TEXT_V1);
	if (keymap_str == NULL) {
		wlr_log(WLR_ERROR, "Failed to get string version of keymap");
		goto error_xkb_state;
	}
	size_t keymap_size = strlen(keymap_str) + 1;

	int rw_fd = -1, ro_fd = -1;
	if (!allocate_shm_file_pair(keymap_size, &rw_fd, &ro_fd)) {
		wlr_log(WLR_ERROR, "Failed to allocate shm file for keymap");
		goto error_keymap_str;
	}

	void *dst = mmap(NULL, keymap_size, PROT_READ | PROT_WRITE, MAP_SHARED, rw_fd, 0);
	close(rw_fd);
	if (dst == MAP_FAILED) {
		wlr_log_errno(WLR_ERROR, "mmap failed");
		close(ro_fd);
		goto error_keymap_str;
	}

	memcpy(dst, keymap_str, keymap_size);
	munmap(dst, keymap_size);

	keyboard_unset_keymap(kb);
	kb->keymap = xkb_keymap_ref(keymap);
	kb->xkb_state = xkb_state;
	kb->keymap_string = keymap_str;
	kb->keymap_size = keymap_size;
	kb->keymap_fd = ro_fd;

	const char *led_names[WLR_LED_COUNT] = {
		XKB_LED_NAME_NUM,
		XKB_LED_NAME_CAPS,
		XKB_LED_NAME_SCROLL,
	};
	for (size_t i = 0; i < WLR_LED_COUNT; ++i) {
		kb->led_indexes[i] = xkb_map_led_get_index(kb->keymap, led_names[i]);
	}

	const char *mod_names[WLR_MODIFIER_COUNT] = {
		XKB_MOD_NAME_SHIFT,
		XKB_MOD_NAME_CAPS,
		XKB_MOD_NAME_CTRL, // "Control"
		XKB_MOD_NAME_ALT, // "Mod1"
		XKB_MOD_NAME_NUM, // "Mod2"
		"Mod3",
		XKB_MOD_NAME_LOGO, // "Mod4"
		"Mod5",
	};
	// TODO: there's also "Ctrl", "Alt"?
	for (size_t i = 0; i < WLR_MODIFIER_COUNT; ++i) {
		kb->mod_indexes[i] = xkb_map_mod_get_index(kb->keymap, mod_names[i]);
	}

	for (size_t i = 0; i < kb->num_keycodes; ++i) {
		xkb_keycode_t keycode = kb->keycodes[i] + 8;
		xkb_state_update_key(kb->xkb_state, keycode, XKB_KEY_DOWN);
	}

	keyboard_modifier_update(kb);

	wl_signal_emit_mutable(&kb->events.keymap, kb);

	return true;

error_keymap_str:
	free(keymap_str);
error_xkb_state:
	xkb_state_unref(xkb_state);
	return false;
}

void wlr_keyboard_set_repeat_info(struct wlr_keyboard *kb, int32_t rate,
		int32_t delay) {
	if (kb->repeat_info.rate == rate && kb->repeat_info.delay == delay) {
		return;
	}
	kb->repeat_info.rate = rate;
	kb->repeat_info.delay = delay;
	wl_signal_emit_mutable(&kb->events.repeat_info, kb);
}

uint32_t wlr_keyboard_get_modifiers(struct wlr_keyboard *kb) {
	xkb_mod_mask_t mask = kb->modifiers.depressed | kb->modifiers.latched;
	uint32_t modifiers = 0;
	for (size_t i = 0; i < WLR_MODIFIER_COUNT; ++i) {
		if (kb->mod_indexes[i] != XKB_MOD_INVALID &&
				(mask & (1 << kb->mod_indexes[i]))) {
			modifiers |= (1 << i);
		}
	}
	return modifiers;
}

bool wlr_keyboard_keymaps_match(struct xkb_keymap *km1,
		struct xkb_keymap *km2) {
	if (!km1 && !km2) {
		return true;
	}
	if (!km1 || !km2) {
		return false;
	}
	char *km1_str = xkb_keymap_get_as_string(km1, XKB_KEYMAP_FORMAT_TEXT_V1);
	char *km2_str = xkb_keymap_get_as_string(km2, XKB_KEYMAP_FORMAT_TEXT_V1);
	bool result = strcmp(km1_str, km2_str) == 0;
	free(km1_str);
	free(km2_str);
	return result;
}

uint32_t wlr_keyboard_keysym_to_pointer_button(xkb_keysym_t keysym) {
	switch (keysym) {
	case XKB_KEY_Pointer_Button1:
		return BTN_LEFT;
	case XKB_KEY_Pointer_Button2:
		return BTN_MIDDLE;
	case XKB_KEY_Pointer_Button3:
		return BTN_RIGHT;
	default:
		return 0;
	}
}

void wlr_keyboard_keysym_to_pointer_motion(xkb_keysym_t keysym, int *dx, int *dy) {
	*dx = 0;
	switch (keysym) {
	case XKB_KEY_Pointer_Right:
	case XKB_KEY_Pointer_DownRight:
	case XKB_KEY_Pointer_UpRight:
		*dx = 1;
		break;
	case XKB_KEY_Pointer_Left:
	case XKB_KEY_Pointer_DownLeft:
	case XKB_KEY_Pointer_UpLeft:
		*dx = -1;
		break;
	}

	*dy = 0;
	switch (keysym) {
	case XKB_KEY_Pointer_Down:
	case XKB_KEY_Pointer_DownLeft:
	case XKB_KEY_Pointer_DownRight:
		*dy = 1;
		break;
	case XKB_KEY_Pointer_Up:
	case XKB_KEY_Pointer_UpLeft:
	case XKB_KEY_Pointer_UpRight:
		*dy = -1;
		break;
	}
}