#include <stdio.h>
#include <string.h>

#include "esp_log.h"
#include "lvgl.h"

#include "lvgl_port.h"
#include "ui_manager.h"

static const char *TAG = "ui_manager";

#define UI_LOCK_TIMEOUT_MS 1000

/*
 * Bring-up diagnostic: a live readout of the last touch coordinate. Off by
 * default -- define UI_DEBUG_TOUCH to put it back on screen when working on
 * the input path.
 */
/* #define UI_DEBUG_TOUCH */

static lv_obj_t *temp_label = NULL;
static lv_obj_t *cond_label = NULL;
static lv_obj_t *status_label = NULL;
#ifdef UI_DEBUG_TOUCH
static lv_obj_t *touch_label = NULL;
#endif

/*
 * lv_label_set_text() invalidates the label unconditionally, even when the
 * new text is identical -- which would repaint the temperature every poll
 * whether or not it moved. Comparing first means an unchanged value costs
 * nothing: no invalidation, so no redraw and no flush.
 */
static void label_set_if_changed(lv_obj_t *label, const char *text)
{
    if (label == NULL || text == NULL) {
        return;
    }

    const char *current = lv_label_get_text(label);
    if (current != NULL && strcmp(current, text) == 0) {
        return;
    }

    lv_label_set_text(label, text);
}

/*
 * NOTE, even with the readout compiled out: LVGL does not bubble events to
 * parents by default. An event handler on the screen object never fires for
 * taps landing on a child widget -- the header or the temperature card
 * consume them -- which presents as whole regions of the panel being dead to
 * touch while the hardware reports them perfectly well. Anything that needs
 * to observe touches screen-wide must poll the input device, as below, rather
 * than hang an event handler on the screen.
 */
#ifdef UI_DEBUG_TOUCH
static void touch_readout_timer_cb(lv_timer_t *timer)
{
    lv_indev_t *indev = lv_indev_get_next(NULL);
    if (indev == NULL || touch_label == NULL) {
        return;
    }

    lv_point_t p;
    lv_indev_get_point(indev, &p);

    char buf[48];
    if (lv_indev_get_state(indev) == LV_INDEV_STATE_PRESSED) {
        snprintf(buf, sizeof(buf), "touch  %d, %d", (int)p.x, (int)p.y);
    } else {
        snprintf(buf, sizeof(buf), "touch  %d, %d  (released)", (int)p.x, (int)p.y);
    }
    label_set_if_changed(touch_label, buf);
}
#endif

void ui_update_weather(int16_t temp_f, const char *condition)
{
    if (!lvgl_port_lock(UI_LOCK_TIMEOUT_MS)) {
        ESP_LOGW(TAG, "Dropped weather update: LVGL lock timed out");
        return;
    }

    char buf[32];
    snprintf(buf, sizeof(buf), "%d°F", temp_f);
    label_set_if_changed(temp_label, buf);
    label_set_if_changed(cond_label, condition);

    lvgl_port_unlock();
}

void ui_set_weather_stale(bool stale)
{
    if (!lvgl_port_lock(UI_LOCK_TIMEOUT_MS)) {
        ESP_LOGW(TAG, "Dropped stale-state update: LVGL lock timed out");
        return;
    }

    if (temp_label != NULL) {
        /* Unlike lv_label_set_text(), setting an identical style value does
         * not invalidate, so this is safe to call on every poll. */
        lv_obj_set_style_text_color(temp_label,
                                    stale ? lv_color_hex(0x5A6672) : lv_color_white(),
                                    LV_PART_MAIN);
    }

    lvgl_port_unlock();
}

void ui_set_status(const char *status)
{
    if (status == NULL) {
        return;
    }

    if (!lvgl_port_lock(UI_LOCK_TIMEOUT_MS)) {
        ESP_LOGW(TAG, "Dropped status update: LVGL lock timed out");
        return;
    }

    label_set_if_changed(status_label, status);

    lvgl_port_unlock();
}

void ui_init(void)
{
    /* ui_init() runs from app_main, not the LVGL task, so it needs the lock
     * like any other outside caller. */
    if (!lvgl_port_lock(UI_LOCK_TIMEOUT_MS)) {
        ESP_LOGE(TAG, "Could not acquire LVGL lock for UI init");
        return;
    }

    lv_obj_t *scr = lv_screen_active();
    lv_obj_set_style_bg_color(scr, lv_color_hex(0x1A2332), LV_PART_MAIN);
    lv_obj_set_style_pad_all(scr, 0, LV_PART_MAIN);
    lv_obj_set_flex_flow(scr, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_flex_align(scr, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER,
                          LV_FLEX_ALIGN_CENTER);

    lv_obj_t *header = lv_obj_create(scr);
    lv_obj_set_size(header, LV_PCT(100), 64);
    lv_obj_set_style_radius(header, 0, LV_PART_MAIN);
    lv_obj_set_style_bg_color(header, lv_color_hex(0x0D1620), LV_PART_MAIN);
    lv_obj_set_style_border_width(header, 0, LV_PART_MAIN);
    lv_obj_clear_flag(header, LV_OBJ_FLAG_SCROLLABLE);

    lv_obj_t *title = lv_label_create(header);
    lv_label_set_text(title, "Thermostat");
    lv_obj_set_style_text_color(title, lv_color_white(), LV_PART_MAIN);
    lv_obj_set_style_text_font(title, &lv_font_montserrat_28, LV_PART_MAIN);
    lv_obj_center(title);

    lv_obj_t *card = lv_obj_create(scr);
    lv_obj_set_size(card, LV_PCT(80), LV_SIZE_CONTENT);
    lv_obj_set_style_bg_color(card, lv_color_hex(0x2C3E50), LV_PART_MAIN);
    lv_obj_set_style_border_width(card, 2, LV_PART_MAIN);
    lv_obj_set_style_border_color(card, lv_color_hex(0x3498DB), LV_PART_MAIN);
    lv_obj_set_style_radius(card, 12, LV_PART_MAIN);
    lv_obj_set_style_pad_all(card, 24, LV_PART_MAIN);
    lv_obj_set_flex_flow(card, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_flex_align(card, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER,
                          LV_FLEX_ALIGN_CENTER);
    lv_obj_clear_flag(card, LV_OBJ_FLAG_SCROLLABLE);

    temp_label = lv_label_create(card);
    lv_label_set_text(temp_label, "--°F");
    lv_obj_set_style_text_color(temp_label, lv_color_white(), LV_PART_MAIN);
    lv_obj_set_style_text_font(temp_label, &lv_font_montserrat_48, LV_PART_MAIN);

    cond_label = lv_label_create(card);
    lv_label_set_text(cond_label, "Waiting for data...");
    lv_obj_set_style_text_color(cond_label, lv_color_hex(0xBDC3C7), LV_PART_MAIN);

    status_label = lv_label_create(scr);
    lv_label_set_text(status_label, "Starting...");
    lv_obj_set_style_text_color(status_label, lv_color_hex(0x7F8C8D), LV_PART_MAIN);

#ifdef UI_DEBUG_TOUCH
    touch_label = lv_label_create(scr);
    lv_label_set_text(touch_label, "touch  --, --");
    lv_obj_set_style_text_color(touch_label, lv_color_hex(0x3498DB), LV_PART_MAIN);

    lv_timer_create(touch_readout_timer_cb, 100, NULL);
#endif

    lvgl_port_unlock();

    ESP_LOGI(TAG, "UI initialized");
}