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

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"

#include "esp_system.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include "nvs.h"
#include "esp_netif.h"
#include "esp_wifi.h"
#include "esp_event.h"

#include "driver/usb_serial_jtag.h"
#include "esp_vfs_dev.h"

#include "wifi_cfg.h"

static const char *TAG = "wifi_cfg";

static void trim(char *s){
    int n = strlen(s);
    while(n>0 && (s[n-1]=='\r' || s[n-1]=='\n' || isspace((unsigned char)s[n-1]))) s[--n]=0;
    while(*s && isspace((unsigned char)*s)){
        memmove(s, s+1, strlen(s));
    }
}

static esp_err_t nvs_set_str2(nvs_handle_t h, const char *key, const char *val){
    return val ? nvs_set_str(h, key, val) : nvs_erase_key(h, key);
}

static bool cfg_dhcp = true;
static esp_netif_t *sta_netif = NULL;

static void save_cfg(const char* ssid, const char* pass, const char* ip, const char* mask, const char* gw, bool dhcp){
    nvs_handle_t h;
    if (nvs_open("netcfg", NVS_READWRITE, &h) != ESP_OK) return;
    if (ssid) nvs_set_str2(h, "ssid", ssid);
    if (pass) nvs_set_str2(h, "pass", pass);
    if (ip)   nvs_set_str2(h, "ip",   ip);
    if (mask) nvs_set_str2(h, "mask", mask);
    if (gw)   nvs_set_str2(h, "gw",   gw);
    nvs_set_u8(h, "dhcp", dhcp ? 1 : 0);
    nvs_commit(h);
    nvs_close(h);
    cfg_dhcp = dhcp;
}

static bool load_cfg(char* ssid, size_t ssz, char* pass, size_t psz,
                     char* ip, size_t isz, char* mask, size_t msz, char* gw, size_t gsz, bool* dhcp){
    nvs_handle_t h;
    if (nvs_open("netcfg", NVS_READONLY, &h) != ESP_OK) return false;
    size_t len;
    esp_err_t e;
    if ((e = nvs_get_str(h, "ssid", NULL, &len)) != ESP_OK){ nvs_close(h); return false; }
    if (len >= ssz){ nvs_close(h); return false; }
    nvs_get_str(h, "ssid", ssid, &len);
    len = psz; e = nvs_get_str(h, "pass", pass, &len); if (e!=ESP_OK) pass[0]=0;
    len = isz; e = nvs_get_str(h, "ip", ip, &len);     if (e!=ESP_OK) ip[0]=0;
    len = msz; e = nvs_get_str(h, "mask", mask, &len); if (e!=ESP_OK) mask[0]=0;
    len = gsz; e = nvs_get_str(h, "gw", gw, &len);     if (e!=ESP_OK) gw[0]=0;
    uint8_t d=1; nvs_get_u8(h, "dhcp", &d); *dhcp = (d!=0);
    nvs_close(h);
    return true;
}

void wifi_cfg_force_dhcp(bool enable){ cfg_dhcp = enable; }

static void apply_ip_static(const char* ip, const char* mask, const char* gw){
    if (!sta_netif) return;
    esp_netif_ip_info_t info = {0};
    esp_netif_dhcpc_stop(sta_netif);
    info.ip.addr      = esp_ip4addr_aton(ip);
    info.netmask.addr = esp_ip4addr_aton(mask);
    info.gw.addr      = esp_ip4addr_aton(gw);
    ESP_ERROR_CHECK( esp_netif_set_ip_info(sta_netif, &info) );
}

bool wifi_cfg_apply_from_nvs(void){
    char ssid[64]={0}, pass[64]={0}, ip[32]={0}, mask[32]={0}, gw[32]={0};
    bool dhcp = true;
    if (!load_cfg(ssid,sizeof(ssid), pass,sizeof(pass), ip,sizeof(ip), mask,sizeof(mask), gw,sizeof(gw), &dhcp)){
        ESP_LOGW(TAG, "No Wi-Fi config in NVS");
        return false;
    }
    ESP_LOGI(TAG, "Applying Wi-Fi config: SSID=%s DHCP=%d IP=%s", ssid, dhcp, ip);

    static bool inited = false;
    if (!inited){
        ESP_ERROR_CHECK(nvs_flash_init());
        ESP_ERROR_CHECK(esp_netif_init());
        ESP_ERROR_CHECK(esp_event_loop_create_default());
        sta_netif = esp_netif_create_default_wifi_sta();
        wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
        ESP_ERROR_CHECK( esp_wifi_init(&cfg) );
        inited = true;
    }

    wifi_config_t wcfg = {0};
    strncpy((char*)wcfg.sta.ssid, ssid, sizeof(wcfg.sta.ssid)-1);
    strncpy((char*)wcfg.sta.password, pass, sizeof(wcfg.sta.password)-1);
    wcfg.sta.threshold.authmode = WIFI_AUTH_WPA2_PSK;
    wcfg.sta.sae_pwe_h2e = WPA3_SAE_PWE_BOTH;
    ESP_ERROR_CHECK( esp_wifi_set_mode(WIFI_MODE_STA) );
    ESP_ERROR_CHECK( esp_wifi_set_config(WIFI_IF_STA, &wcfg) );

    if (!dhcp && ip[0] && mask[0] && gw[0]){
        apply_ip_static(ip, mask, gw);
    }else{
        if (sta_netif) esp_netif_dhcpc_start(sta_netif);
    }

    ESP_ERROR_CHECK( esp_wifi_start() );
    ESP_ERROR_CHECK( esp_wifi_connect() );
    return true;
}

static void cfg_listener_task(void *arg){
    usb_serial_jtag_driver_config_t dcfg = USB_SERIAL_JTAG_DRIVER_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(usb_serial_jtag_driver_install(&dcfg));

    // Deprecated but functional - causes only a warning
    esp_vfs_usb_serial_jtag_use_driver();

    setvbuf(stdin, NULL, _IONBF, 0);
    setvbuf(stdout, NULL, _IONBF, 0);

    char line[160];
    char ssid[64]={0}, pass[64]={0}, ip[32]={0}, mask[32]={0}, gw[32]={0};
    bool dhcp = true;
    bool in_cfg = false;

    while (1){
        if (!fgets(line, sizeof(line), stdin)){
            vTaskDelay(pdMS_TO_TICKS(50));
            continue;
        }
        trim(line);
        if (!in_cfg){
            if (strcmp(line, "CFG")==0){
                in_cfg = true;
                ssid[0]=pass[0]=ip[0]=mask[0]=gw[0]=0;
                dhcp = true;
            }
            continue;
        }
        if (strcmp(line, "END")==0){
            save_cfg(ssid, pass, ip, mask, gw, dhcp);
            printf("OK\n");
            wifi_cfg_apply_from_nvs();
            in_cfg = false;
            continue;
        }
        if (strncmp(line, "SSID:",5)==0){ strncpy(ssid, line+5, sizeof(ssid)-1); continue; }
        if (strncmp(line, "PASS:",5)==0){ strncpy(pass, line+5, sizeof(pass)-1); continue; }
        if (strncmp(line, "IP:",3)==0){   strncpy(ip,   line+3, sizeof(ip)-1);   continue; }
        if (strncmp(line, "MASK:",5)==0){ strncpy(mask, line+5, sizeof(mask)-1); continue; }
        if (strncmp(line, "GW:",3)==0){   strncpy(gw,   line+3, sizeof(gw)-1);   continue; }
        if (strncmp(line, "DHCP:",5)==0){ dhcp = atoi(line+5) ? true:false;      continue; }
    }
}

void wifi_cfg_init(void){
    nvs_flash_init();
    xTaskCreatePinnedToCore(cfg_listener_task, "cfg_listener",
                            6144, NULL, 5, NULL, tskNO_AFFINITY);
}