/*
 * LLM Proxy Client - C Version (Windows Native using WinINet)
 * Compile: gcc -o llm_client client.c -lwininet
 * Usage: llm_client.exe
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include <wininet.h>

#define MAX_PROMPT_SIZE 4096
#define MAX_RESPONSE_SIZE 65536

typedef struct {
    const char *name;
    const char *id;
} LLMModel;

static const LLMModel MODELS[] = {
    {"Laguna S 2.1 (Free)", "poolside/laguna-s-2.1:free"},
    {"Gemini 3.6 Flash (Paid)", "google/gemini-3.6-flash"},
    {"Claude Opus 5 (Paid)", "anthropic/claude-opus-5"},
    {"Claude Fable 5 (Paid)", "anthropic/claude-fable-5"},
    {"GPT-5.6 Sol (Paid)", "openai/gpt-5.6-sol"},
    {"GPT-5.6 Luna (Paid)", "openai/gpt-5.6-luna"},
    {"Nemotron 3 Ultra (Free)", "nvidia/nemotron-3-ultra-550b-a55b:free"}
};

static const int MODEL_COUNT = sizeof(MODELS) / sizeof(MODELS[0]);

char* ask_llm(const char *prompt, const LLMModel *model) {
    HINTERNET hInternet = NULL, hConnect = NULL, hRequest = NULL;
    char *response = NULL;
    DWORD bytesRead = 0;
    DWORD totalSize = 0;
    char headers[512];
    
    response = (char*)malloc(MAX_RESPONSE_SIZE);
    if (!response) return _strdup("Error: Memory allocation failed");
    memset(response, 0, MAX_RESPONSE_SIZE);

    /* Initialize WinINet */
    hInternet = InternetOpenA("LLM-Proxy-Client/1.0",
                              INTERNET_OPEN_TYPE_PRECONFIG,
                              NULL, NULL, 0);
    if (!hInternet) {
        free(response);
        return _strdup("Error: Failed to open Internet session");
    }

    /* Connect to server */
    hConnect = InternetConnectA(hInternet,
                                "ttl0110-llm-proxy.hf.space",
                                INTERNET_DEFAULT_HTTPS_PORT,
                                NULL, NULL,
                                INTERNET_SERVICE_HTTP,
                                0, 0);
    if (!hConnect) {
        InternetCloseHandle(hInternet);
        free(response);
        return _strdup("Error: Failed to connect to server");
    }

    /* Create request */
    hRequest = HttpOpenRequestA(hConnect, "POST", "/ask",
                                NULL, NULL, NULL,
                                INTERNET_FLAG_SECURE | INTERNET_FLAG_RELOAD,
                                0);
    if (!hRequest) {
        InternetCloseHandle(hConnect);
        InternetCloseHandle(hInternet);
        free(response);
        return _strdup("Error: Failed to create request");
    }

    /* Build headers */
    snprintf(headers, sizeof(headers),
             "Content-Type: text/plain\r\nX-Model: %s",
             model->id);

    /* Send request */
    DWORD promptLen = (DWORD)strlen(prompt);
    if (!HttpSendRequestA(hRequest, headers, (DWORD)strlen(headers),
                          (LPVOID)prompt, promptLen)) {
        DWORD err = GetLastError();
        char errMsg[128];
        snprintf(errMsg, sizeof(errMsg), "Error: Failed to send request (code: %lu)", err);
        InternetCloseHandle(hRequest);
        InternetCloseHandle(hConnect);
        InternetCloseHandle(hInternet);
        free(response);
        return _strdup(errMsg);
    }

    /* Read response data */
    char buffer[4096];
    while (InternetReadFile(hRequest, buffer, sizeof(buffer) - 1, &bytesRead) && bytesRead > 0) {
        if (totalSize + bytesRead < MAX_RESPONSE_SIZE - 1) {
            memcpy(response + totalSize, buffer, bytesRead);
            totalSize += bytesRead;
        }
    }
    response[totalSize] = '\0';

    /* Cleanup */
    InternetCloseHandle(hRequest);
    InternetCloseHandle(hConnect);
    InternetCloseHandle(hInternet);

    return response;
}

void clear_input_buffer(void) {
    int c;
    while ((c = getchar()) != '\n' && c != EOF);
}

int main(void) {
    char prompt[MAX_PROMPT_SIZE];
    char prompt_prefix[MAX_PROMPT_SIZE] = {0};
    int choice = 0;

    /* Set console to UTF-8 */
    SetConsoleOutputCP(CP_UTF8);
    SetConsoleCP(CP_UTF8);

    printf("=== C LLM Assistant (HuggingFace Proxy) ===\n\n");

    /* Model Selection */
    printf("Chon Model LLM:\n");
    for (int i = 0; i < MODEL_COUNT; i++) {
        printf("%d. %s\n", i + 1, MODELS[i].name);
    }

    while (choice < 1 || choice > MODEL_COUNT) {
        printf("Nhap lua chon (1-%d): ", MODEL_COUNT);
        if (scanf("%d", &choice) != 1) {
            clear_input_buffer();
            choice = 0;
        }
    }
    clear_input_buffer();

    const LLMModel *selected_model = &MODELS[choice - 1];
    printf("Ban da chon: %s\n\n", selected_model->name);

    printf("Nhap prompt prefix (bo trong neu khong dung): ");
    if (fgets(prompt_prefix, sizeof(prompt_prefix), stdin) != NULL) {
        prompt_prefix[strcspn(prompt_prefix, "\r\n")] = '\0';
    }

    printf("Huong dan: Nhap prompt cua ban. Nhap dong trong de gui.\n");
    printf("Nhap 'EXIT' de thoat.\n");

    while (1) {
        printf("\nBan [%s]:\n", selected_model->name);

        char full_prompt[MAX_PROMPT_SIZE] = {0};
        size_t total_len = 0;

        while (1) {
            if (fgets(prompt, sizeof(prompt), stdin) == NULL) {
                break;
            }

            /* Check for EXIT command */
            if (_strnicmp(prompt, "EXIT", 4) == 0 && (prompt[4] == '\n' || prompt[4] == '\0')) {
                printf("Tam biet!\n");
                return 0;
            }

            /* Empty line means submit */
            if (prompt[0] == '\n') {
                break;
            }

            size_t line_len = strlen(prompt);
            if (total_len + line_len < MAX_PROMPT_SIZE - 1) {
                strcat(full_prompt, prompt);
                total_len += line_len;
            }
        }

        if (total_len == 0) {
            printf("Prompt trong, vui long nhap lai.\n");
            continue;
        }

        /* Remove trailing newline */
        if (full_prompt[total_len - 1] == '\n') {
            full_prompt[total_len - 1] = '\0';
        }

        char request_prompt[MAX_PROMPT_SIZE] = {0};
        if (prompt_prefix[0] != '\0') {
            int written = snprintf(request_prompt, sizeof(request_prompt), "%s\n\n%s",
                                   prompt_prefix, full_prompt);
            if (written < 0 || written >= (int)sizeof(request_prompt)) {
                printf("Prompt va prefix qua dai, vui long nhap lai.\n");
                continue;
            }
        } else {
            strcpy(request_prompt, full_prompt);
        }

        printf("Thinking...\n");
        char *response = ask_llm(request_prompt, selected_model);

        printf("\n[LLM]: %s\n", response);
        printf("-------------------------------------------\n");

        free(response);
    }

    return 0;
}