#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_timer.h"
#include "esp_system.h"
#include "sdkconfig.h"
#include "soc/rtc_cntl_reg.h"

#include "common.h"
#include "input.h"
#include "lora_radio.h"
#include "ui.h"
#include "usb_api.h"
#include <strings.h>
#include <strings.h>

static const char *TAG = "lora_tx";

typedef enum {
    FIELD_FREQ = 0,
    FIELD_BW,
    FIELD_SF,
    FIELD_CR,
    FIELD_TX_POWER,
    FIELD_PERIOD,
    FIELD_COUNT
} field_t;

typedef enum {
    SCREEN_FREQ = 0,
    SCREEN_BAND,
    SCREEN_BW,
    SCREEN_SF,
    SCREEN_CR,
    SCREEN_POWER,
    SCREEN_PAYLOAD,
    SCREEN_PERIOD,
    SCREEN_TX_ENABLE,
    SCREEN_BOOT,
    SCREEN_COUNT
} screen_t;

static lora_params_t s_params;
static field_t s_field = FIELD_FREQ;
static screen_t s_screen = SCREEN_FREQ;
static const char *s_screen_icon[SCREEN_COUNT] = {"ƒ", "BND", "BW", "SF", "CR", "P", "PKT", "PRD", "ON", "BL"};
static const char *s_screen_label[SCREEN_COUNT] = {"FREQ", "BAND", "BANDW", "SPREAD", "CODERATE", "POWER", "PAYLOAD", "PERIOD", "TX", "BOOT"};

static const int s_bw_options[] = {125, 250, 500};
static const char *s_payload_options[] = {
    "PING 1", "PING 2", "PING 3", "PING 4", "PING 5",
    "PING 6", "PING 7", "PING 8", "PING 9", "PING 10"
};
static int s_payload_idx = 0;
static char s_payload[32] = "PING 1";
static int s_period_ms = 1000;
static int64_t s_last_tx_us = 0;
static bool s_tx_enabled = true;
typedef struct {
    const char *name;
    int min_cmhz;
    int max_cmhz;
    int default_cmhz;
} band_t;
static const band_t s_bands[] = {
    {"430", 43000, 44000, 43300},
    {"868", 86300, 87000, 86800},
    {"915", 90200, 92800, 91500},
    {"L", 152500, 166000, 155000},   // 1.525-1.660 GHz
    {"S", 190000, 210000, 200000},   // 1.9-2.1 GHz
    {"2.4G", 240000, 248350, 244200}, // 2.4 GHz ISM (2400-2483.5 MHz)
};
static int s_band_idx = 0;

// --- JSON helpers for USB control -------------------------------------------------

static void sanitize_json_string(const char *in, char *out, size_t out_len)
{
    if (!out || out_len == 0) {
        return;
    }
    size_t w = 0;
    for (size_t i = 0; in && in[i] != '\0' && w + 1 < out_len; i++) {
        char c = in[i];
        if (c == '\\' || c == '\"' || (unsigned char)c < 0x20) {
            out[w++] = ' ';
        } else {
            out[w++] = c;
        }
    }
    out[w] = '\0';
}

static bool parse_int_field(const char *json, const char *key, int *out)
{
    if (!json || !key || !out) {
        return false;
    }
    char pattern[32];
    snprintf(pattern, sizeof(pattern), "\"%s\"", key);
    const char *p = strstr(json, pattern);
    if (!p) return false;
    p = strchr(p, ':');
    if (!p) return false;
    p++;
    int val = 0;
    if (sscanf(p, " %d", &val) == 1) {
        *out = val;
        return true;
    }
    return false;
}

static bool parse_string_field(const char *json, const char *key, char *out, size_t out_len)
{
    if (!json || !key || !out || out_len == 0) {
        return false;
    }
    char pattern[32];
    snprintf(pattern, sizeof(pattern), "\"%s\"", key);
    const char *p = strstr(json, pattern);
    if (!p) return false;
    p = strchr(p, ':');
    if (!p) return false;
    const char *q = strchr(p, '\"');
    if (!q) return false;
    q++; // after quote
    const char *end = strchr(q, '\"');
    if (!end) return false;
    size_t len = (size_t)(end - q);
    if (len >= out_len) len = out_len - 1;
    memcpy(out, q, len);
    out[len] = '\0';
    return true;
}

static bool parse_bool_field(const char *json, const char *key, bool *out)
{
    if (!json || !key || !out) {
        return false;
    }
    char pattern[32];
    snprintf(pattern, sizeof(pattern), "\"%s\"", key);
    const char *p = strstr(json, pattern);
    if (!p) return false;
    p = strchr(p, ':');
    if (!p) return false;
    p++;
    if (strncmp(p, " true", 5) == 0 || strncmp(p, "true", 4) == 0 || strncmp(p, "1", 1) == 0) {
        *out = true;
        return true;
    }
    if (strncmp(p, " false", 6) == 0 || strncmp(p, "false", 5) == 0 || strncmp(p, "0", 1) == 0) {
        *out = false;
        return true;
    }
    return false;
}

static int find_band_idx(const char *name)
{
    if (!name) return -1;
    for (size_t i = 0; i < sizeof(s_bands)/sizeof(s_bands[0]); i++) {
        if (strcasecmp(name, s_bands[i].name) == 0) {
            return (int)i;
        }
    }
    return -1;
}

static void apply_payload_selection(void)
{
    if (s_payload_idx < 0) {
        s_payload_idx = 0;
    }
    int max_idx = (int)(sizeof(s_payload_options) / sizeof(s_payload_options[0])) - 1;
    if (s_payload_idx > max_idx) {
        s_payload_idx = max_idx;
    }
    strlcpy(s_payload, s_payload_options[s_payload_idx], sizeof(s_payload));
}

static void change_payload(int delta)
{
    s_payload_idx += delta;
    apply_payload_selection();
}

static int detect_band_from_freq(int cmhz)
{
    for (size_t i = 0; i < sizeof(s_bands) / sizeof(s_bands[0]); i++) {
        if (cmhz >= s_bands[i].min_cmhz && cmhz <= s_bands[i].max_cmhz) {
            return (int)i;
        }
    }
    return 0;
}

static void clamp_freq_to_band(void)
{
    const band_t *b = &s_bands[s_band_idx];
    if (s_params.freq_centi_mhz < b->min_cmhz) s_params.freq_centi_mhz = b->min_cmhz;
    if (s_params.freq_centi_mhz > b->max_cmhz) s_params.freq_centi_mhz = b->max_cmhz;
    s_params.freq_centi_mhz = ((s_params.freq_centi_mhz + 50) / 100) * 100;
}

static void usb_send_status(void)
{
    lora_metrics_t metrics = {0};
    lora_radio_get_metrics(&metrics);
    char line[256];
    snprintf(line, sizeof(line),
             "{\"resp\":\"status\",\"role\":\"tx\",\"freq_mhz\":%d,\"bw_khz\":%d,\"sf\":%d,\"cr\":%d,"
             "\"band\":\"%s\",\"tx_power_dbm\":%d,\"period_ms\":%d,\"tx_enabled\":%s,"
             "\"snr_db\":%d,\"rssi_dbm\":%d,\"last_status\":%u}\n",
             s_params.freq_centi_mhz / 100,
             s_params.bw_khz,
             s_params.sf,
             s_params.cr,
             s_bands[s_band_idx].name,
             s_params.tx_power_dbm,
             s_period_ms,
             s_tx_enabled ? "true" : "false",
             metrics.snr_db,
             metrics.rssi_dbm,
             (unsigned)metrics.last_status);
    usb_api_send_line(line);
}

static void usb_handle_set_params(const char *json)
{
    bool radio_changed = false;
    lora_params_t next = s_params;

    int band_idx = -1;
    char band_name[16] = {0};
    if (parse_string_field(json, "band", band_name, sizeof(band_name))) {
        band_idx = find_band_idx(band_name);
        if (band_idx >= 0) {
            s_band_idx = band_idx;
            radio_changed = true;
        }
    }

    int val = 0;
    if (parse_int_field(json, "freq_mhz", &val)) {
        next.freq_centi_mhz = val * 100;
        radio_changed = true;
    }
    if (parse_int_field(json, "bw_khz", &val)) {
        next.bw_khz = val;
        radio_changed = true;
    }
    if (parse_int_field(json, "sf", &val)) {
        next.sf = val;
        radio_changed = true;
    }
    if (parse_int_field(json, "cr", &val)) {
        next.cr = val;
        radio_changed = true;
    }
    if (parse_int_field(json, "tx_power_dbm", &val)) {
        next.tx_power_dbm = val;
        radio_changed = true;
    }

    bool ctrl_changed = false;
    if (parse_int_field(json, "period_ms", &val)) {
        s_period_ms = val;
        if (s_period_ms < 100) s_period_ms = 100;
        if (s_period_ms > 60000) s_period_ms = 60000;
        ctrl_changed = true;
    }
    bool bval = false;
    if (parse_bool_field(json, "tx_enabled", &bval)) {
        s_tx_enabled = bval;
        ctrl_changed = true;
    }
    char payload[64] = {0};
    if (parse_string_field(json, "payload", payload, sizeof(payload))) {
        sanitize_json_string(payload, payload, sizeof(payload));
        strlcpy(s_payload, payload, sizeof(s_payload));
        ctrl_changed = true;
    }

    if (radio_changed) {
        s_params = next;
        clamp_freq_to_band();
        esp_err_t err = lora_radio_apply_params(&s_params);
        if (err != ESP_OK) {
            ESP_LOGE(TAG, "USB set_params failed: %s", esp_err_to_name(err));
        } else {
            ESP_LOGI(TAG, "USB set_params applied");
        }
    } else if (!ctrl_changed) {
        // nothing to do
        return;
    }
}

static void usb_handle_line(const char *line)
{
    if (!line || line[0] == '\0') {
        return;
    }
    ESP_LOGI(TAG, "USB RX: %s", line);
    if (strstr(line, "set_params")) {
        usb_handle_set_params(line);
        return;
    }
    if (strstr(line, "get_status")) {
        usb_send_status();
        return;
    }
    if (strstr(line, "reboot_bootloader")) {
        ui_show_status("Bootloader", "Rebooting to USB", "Connect USB", NULL, NULL, NULL);
        vTaskDelay(pdMS_TO_TICKS(200));
        REG_SET_BIT(RTC_CNTL_OPTIONS0_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
        esp_restart();
    }
}

static void set_band(int idx)
{
    int max_idx = (int)(sizeof(s_bands) / sizeof(s_bands[0])) - 1;
    if (idx < 0) idx = 0;
    if (idx > max_idx) idx = max_idx;
    s_band_idx = idx;
    s_params.freq_centi_mhz = s_bands[s_band_idx].default_cmhz;
    clamp_freq_to_band();
    esp_err_t err = lora_radio_apply_params(&s_params);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Apply params failed: %s", esp_err_to_name(err));
    }
}

static void bump_field(int delta)
{
    switch (s_field) {
    case FIELD_FREQ:
        s_params.freq_centi_mhz += delta * 100; // крок 1 MHz
        clamp_freq_to_band();
        break;
    case FIELD_BW: {
        int idx = 0;
        for (size_t i = 0; i < sizeof(s_bw_options)/sizeof(s_bw_options[0]); i++) {
            if (s_bw_options[i] == s_params.bw_khz) {
                idx = i;
                break;
            }
        }
        idx += delta;
        if (idx < 0) idx = 0;
        if (idx >= (int)(sizeof(s_bw_options)/sizeof(s_bw_options[0]))) idx = (int)(sizeof(s_bw_options)/sizeof(s_bw_options[0])) - 1;
        s_params.bw_khz = s_bw_options[idx];
        break;
    }
    case FIELD_SF:
        s_params.sf += delta;
        if (s_params.sf < 5) s_params.sf = 5;
        if (s_params.sf > 12) s_params.sf = 12;
        break;
    case FIELD_CR:
        s_params.cr += delta;
        if (s_params.cr < 5) s_params.cr = 5;
        if (s_params.cr > 8) s_params.cr = 8;
        break;
    case FIELD_TX_POWER:
        s_params.tx_power_dbm += delta;
        break;
    case FIELD_PERIOD:
        s_period_ms += delta * 100;
        if (s_period_ms < 100) s_period_ms = 100;
        if (s_period_ms > 60000) s_period_ms = 60000;
        break;
    default:
        break;
    }
    esp_err_t err = lora_radio_apply_params(&s_params);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Apply params failed: %s", esp_err_to_name(err));
    }
}

static void next_screen(int delta)
{
    int idx = (int)s_screen + delta;
    if (idx < 0) idx = SCREEN_COUNT - 1;
    if (idx >= SCREEN_COUNT) idx = 0;
    s_screen = (screen_t)idx;
    switch (s_screen) {
    case SCREEN_FREQ: s_field = FIELD_FREQ; break;
    case SCREEN_BAND: s_field = FIELD_FREQ; break;
    case SCREEN_BW: s_field = FIELD_BW; break;
    case SCREEN_SF: s_field = FIELD_SF; break;
    case SCREEN_CR: s_field = FIELD_CR; break;
    case SCREEN_POWER: s_field = FIELD_TX_POWER; break;
    case SCREEN_PERIOD: s_field = FIELD_PERIOD; break;
    case SCREEN_BOOT: s_field = FIELD_FREQ; break;
    default: break;
    }
}

static void adjust_current(int delta)
{
    switch (s_screen) {
    case SCREEN_FREQ: s_field = FIELD_FREQ; bump_field(delta); break;
    case SCREEN_BAND: set_band(s_band_idx + delta); break;
    case SCREEN_BW:   s_field = FIELD_BW;   bump_field(delta); break;
    case SCREEN_SF:   s_field = FIELD_SF;   bump_field(delta); break;
    case SCREEN_CR:   s_field = FIELD_CR;   bump_field(delta); break;
    case SCREEN_POWER: s_field = FIELD_TX_POWER; bump_field(delta); break;
    case SCREEN_PERIOD: s_field = FIELD_PERIOD; bump_field(delta); break;
    case SCREEN_PAYLOAD: change_payload(delta); break;
    case SCREEN_BOOT: break;
    default:
        break;
    }
}

static void app_loop(void)
{
    lora_metrics_t metrics = {0};
    while (true) {
        input_event_t evt = input_poll();
        switch (evt) {
            case INPUT_LEFT: next_screen(-1); break;
            case INPUT_RIGHT: next_screen(1); break;
            case INPUT_UP:
                if (s_screen == SCREEN_TX_ENABLE) {
                    s_tx_enabled = true;
                } else {
                    adjust_current(1);
                }
                break;
            case INPUT_DOWN:
                if (s_screen == SCREEN_TX_ENABLE) {
                    s_tx_enabled = false;
                } else {
                    adjust_current(-1);
                }
                break;
            case INPUT_CENTER:
                if (s_screen == SCREEN_TX_ENABLE) {
                    s_tx_enabled = !s_tx_enabled;
                } else if (s_screen == SCREEN_BOOT) {
                    ui_show_status("Bootloader", "Rebooting to USB", "Connect USB", NULL, NULL, NULL);
                    vTaskDelay(pdMS_TO_TICKS(200));
                    REG_SET_BIT(RTC_CNTL_OPTIONS0_REG, RTC_CNTL_FORCE_DOWNLOAD_BOOT);
                    esp_restart();
                } else {
                    bump_field(0);
                }
                break;
            default: break;
        }

        usb_api_tick();
        lora_radio_tick_tx();
        lora_radio_get_metrics(&metrics);
        // Періодична передача
        int64_t now = esp_timer_get_time();
        if (s_tx_enabled && now - s_last_tx_us >= (int64_t)s_period_ms * 1000) {
            size_t len = strnlen(s_payload, sizeof(s_payload));
            if (len > 0) {
                esp_err_t tx_err = lora_radio_send((const uint8_t *)s_payload, len);
                if (tx_err == ESP_OK) {
                    s_last_tx_us = now;
                    ESP_LOGI(TAG, "TX \"%s\" (%u bytes)", s_payload, (unsigned)len);
                } else {
                    ESP_LOGW(TAG, "TX failed: %s", esp_err_to_name(tx_err));
                    s_last_tx_us = now; // уникнути спаму
                }
            }
        }
        char line1[32];
        char line2[32];
        char line3[32];
        char line4[32];
        char line5[32];
        char line6[32];
        memset(line1, 0, sizeof(line1));
        memset(line2, 0, sizeof(line2));
        memset(line3, 0, sizeof(line3));
        memset(line4, 0, sizeof(line4));
        memset(line5, 0, sizeof(line5));
        memset(line6, 0, sizeof(line6));

        switch (s_screen) {
        case SCREEN_FREQ:
            snprintf(line1, sizeof(line1), "Freq: %d MHz", s_params.freq_centi_mhz / 100);
            snprintf(line2, sizeof(line2), "UP/DN to change");
            break;
        case SCREEN_BAND: {
            const band_t *b = &s_bands[s_band_idx];
            snprintf(line1, sizeof(line1), "Band %s", b->name);
            snprintf(line2, sizeof(line2), "%d-%d MHz", b->min_cmhz / 100, b->max_cmhz / 100);
            snprintf(line3, sizeof(line3), "UP/DN to select");
            break;
        }
        case SCREEN_BW:
            snprintf(line1, sizeof(line1), "BW: %d kHz", s_params.bw_khz);
            snprintf(line2, sizeof(line2), "UP/DN to change");
            break;
        case SCREEN_SF:
            snprintf(line1, sizeof(line1), "SF: %d", s_params.sf);
            snprintf(line2, sizeof(line2), "UP/DN to change");
            break;
        case SCREEN_CR:
            snprintf(line1, sizeof(line1), "CR: 4/%d", s_params.cr);
            snprintf(line2, sizeof(line2), "UP/DN to change");
            break;
        case SCREEN_POWER:
            snprintf(line1, sizeof(line1), "PWR: %d dBm", s_params.tx_power_dbm);
            snprintf(line2, sizeof(line2), "UP/DN to change");
            break;
        case SCREEN_PAYLOAD:
            snprintf(line1, sizeof(line1), "Payload:");
            snprintf(line2, sizeof(line2), "%.31s", s_payload);
            snprintf(line3, sizeof(line3), "UP/DN pick PING");
            break;
        case SCREEN_PERIOD:
            snprintf(line1, sizeof(line1), "Period: %d ms", s_period_ms);
            snprintf(line2, sizeof(line2), "UP/DN to change");
            break;
        case SCREEN_TX_ENABLE:
            snprintf(line1, sizeof(line1), "TX: %s", s_tx_enabled ? "ON" : "OFF");
            snprintf(line2, sizeof(line2), "UP=on DN=off CTR=tgl");
            break;
        case SCREEN_BOOT:
            snprintf(line1, sizeof(line1), "USB Bootloader");
            snprintf(line2, sizeof(line2), "CENTER to reboot");
            snprintf(line3, sizeof(line3), "Plug USB first");
            break;
        default:
            break;
        }

        snprintf(line4, sizeof(line4), "SNR %ddB", metrics.snr_db);
        snprintf(line5, sizeof(line5), "RSSI %ddBm ST 0x%02X", metrics.rssi_dbm, metrics.last_status);

        char header[32];
        snprintf(header, sizeof(header), "%s %s", s_screen_icon[s_screen], s_screen_label[s_screen]);
        ui_show_role(header);
        ui_show_status(line1, line2, line3, line4, line5, line6);
        vTaskDelay(pdMS_TO_TICKS(500));
    }
}

void app_main(void)
{
    common_print_boot_info();
    input_init();
    ui_init();
    ui_show_role("TX");
    bool radio_ok = lora_radio_init(true);
    ui_show_status(radio_ok ? "LR1121 OK" : "LR1121 FAIL", "Ready", NULL, NULL, NULL, NULL);
    ESP_LOGI(TAG, "LR1121 init: %s", radio_ok ? "OK" : "FAIL");
    s_params.freq_centi_mhz = CONFIG_LORA_FREQ_MHZ * 100;
    s_params.bw_khz = CONFIG_LORA_BW_KHZ;
    s_params.sf = CONFIG_LORA_SF;
    s_params.cr = CONFIG_LORA_CR;
    s_params.tx_power_dbm = 14;
    s_params.preamble_syms = 8;
    s_params.payload_len = 0;
    s_params.crc_on = true;
    s_params.iq_invert = false;
    s_params.header_implicit = false;
    apply_payload_selection();
    s_band_idx = detect_band_from_freq(s_params.freq_centi_mhz);
    clamp_freq_to_band();
    esp_err_t err = lora_radio_apply_params(&s_params);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Initial params failed: %s", esp_err_to_name(err));
    }
    usb_api_init(usb_handle_line);
    app_loop();
}