/**
 * @file display.c
 * @brief Display manager - main screen and OLED rendering
 */
#include <stdio.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "oled.h"
#include "display.h"
#include "app_main.h"

static const char *TAG = "display";

/* Display state */
static display_mode_t current_mode = DISPLAY_MODE_CHANNELS;

/* Format buffer (unused currently) */
//static char line_buf[24];

void display_init(void)
{
    oled_init(OLED_SDA_GPIO, OLED_SCL_GPIO);
    ESP_LOGI(TAG, "Display initialized");
}

void display_set_mode(display_mode_t mode)
{
    current_mode = mode;
}

void display_update(adc_data_t *adc_data)
{
    oled_clear();
    
    /* Draw top bar (yellow area - first 16px) */
    /* Signal strength, flight battery, TX battery */
    oled_draw_string(0, 0, "ALICERC v1.0", OLED_COLOR_WHITE);
    
    /* Draw horizontal separator */
    oled_draw_hline(0, 16, OLED_WIDTH, OLED_COLOR_WHITE);
    
    /* Draw main content based on mode */
    switch (current_mode) {
        case DISPLAY_MODE_CHANNELS:
            display_draw_channels(adc_data);
            break;
        case DISPLAY_MODE_TELEMETRY:
            display_draw_telemetry(adc_data);
            break;
        case DISPLAY_MODE_MENU:
            /* Menu drawing handled by menu system */
            break;
    }
    
    oled_update();
}

void display_draw_channels(adc_data_t *adc_data)
{
    char buf[32];
    uint8_t y = 20;
    
    /* Draw 8 channel values in 4 rows of 2 */
    for (int i = 0; i < 8; i += 2) {
        snprintf(buf, sizeof(buf), "CH%d:%4d CH%d:%4d", 
                 i + 1, adc_data->channels[i],
                 i + 2, adc_data->channels[i + 1]);
        oled_draw_string(0, y, buf, OLED_COLOR_WHITE);
        y += 10;
    }
    
    /* Draw battery voltage */
    snprintf(buf, sizeof(buf), "BAT:%4dmV %3d%%", 
             adc_data->battery_mv,
             battery_get_percent(adc_data->battery_mv));
    oled_draw_string(0, y, buf, OLED_COLOR_WHITE);
}

void display_draw_telemetry(adc_data_t *adc_data)
{
    char buf[32];
    
    /* Placeholder for telemetry display */
    snprintf(buf, sizeof(buf), "RSSI: --  Link: --");
    oled_draw_string(0, 20, buf, OLED_COLOR_WHITE);
    
    snprintf(buf, sizeof(buf), "RX Batt: -- mV");
    oled_draw_string(0, 30, buf, OLED_COLOR_WHITE);
}

void display_show_message(const char *msg, uint16_t duration_ms)
{
    oled_clear();
    oled_draw_string(0, 28, msg, OLED_COLOR_WHITE);
    oled_update();
    vTaskDelay(pdMS_TO_TICKS(duration_ms));
}