// beyond_prox_ctl - Control tool for Beyond Proximity SteamVR driver
// Sends commands to the driver via named pipe and prints response.
//
// Usage:
//   beyond_prox_ctl "proximity on"    -- Set proximity to true (HMD in use)
//   beyond_prox_ctl "proximity off"   -- Set proximity to false (HMD idle)
//   beyond_prox_ctl "status"          -- Query current driver state
//   beyond_prox_ctl "ipd 63.5"        -- Set IPD to 63.5mm
//   beyond_prox_ctl "ipd?"            -- Query current IPD
//   beyond_prox_ctl "backglow fill FF0000"       -- Set all 10 LEDs red
//   beyond_prox_ctl "backglow set 3 00FF00"      -- Light only LED 3 green
//   beyond_prox_ctl "backglow bri 100"           -- Set master brightness
//   beyond_prox_ctl "backglow off"               -- Turn LEDs off
//   beyond_prox_ctl "backglow on"                -- Turn LEDs on
//
// Pipe: \\.\pipe\beyond_proximity_ctl

#include <windows.h>
#include <cstdio>
#include <cstring>

static const char* PIPE_NAME = "\\\\.\\pipe\\beyond_proximity_ctl";

static void PrintUsage(const char* argv0)
{
    fprintf(stderr, "Usage: %s <command>\n", argv0);
    fprintf(stderr, "\nCommands:\n");
    fprintf(stderr, "  \"proximity on\"         Set proximity to true (person detected)\n");
    fprintf(stderr, "  \"proximity off\"        Set proximity to false (no person)\n");
    fprintf(stderr, "  \"proximity auto\"       Clear manual override, let algorithm drive\n");
    fprintf(stderr, "  \"status\"               Query driver state (proximity, HID, IPD, config)\n");
    fprintf(stderr, "  \"ipd <mm>\"             Set IPD in millimeters (48-75mm range)\n");
    fprintf(stderr, "  \"ipd?\"                 Query current IPD value\n");
    fprintf(stderr, "  \"load_lh_config <path>\" Load lighthouse config from explicit file path\n");
    fprintf(stderr, "  \"backglow fill <hex>\"       Set all 10 LEDs (e.g. backglow fill FF8000)\n");
    fprintf(stderr, "  \"backglow fill <h0> ... <h9>\" Set per-LED colors (10 hex values)\n");
    fprintf(stderr, "  \"backglow set <idx> <hex>\"  Set single LED (idx 0..9, hex RRGGBB)\n");
    fprintf(stderr, "  \"backglow bri <0..255>\"     Set master brightness (clamped by ceiling)\n");
    fprintf(stderr, "  \"backglow off\"              Turn LEDs off\n");
    fprintf(stderr, "  \"backglow on\"               Turn LEDs on\n");
    fprintf(stderr, "  \"backglow status\"           Show transport/conn/port|host/bri/ceiling/leds (multi-line)\n");
}

int main(int argc, char* argv[])
{
    if (argc < 2)
    {
        PrintUsage(argv[0]);
        return 1;
    }

    const char* command = argv[1];

    // Validate known commands
    bool validCommand =
        strcmp(command, "proximity on") == 0 ||
        strcmp(command, "proximity off") == 0 ||
        strcmp(command, "proximity auto") == 0 ||
        strcmp(command, "status") == 0 ||
        strncmp(command, "ipd ", 4) == 0 ||
        strcmp(command, "ipd?") == 0 ||
        strncmp(command, "load_lh_config ", 15) == 0
        || strncmp(command, "backglow fill", 13) == 0
        || strncmp(command, "backglow set ", 13) == 0
        || strncmp(command, "backglow bri ", 13) == 0
        || strcmp(command, "backglow off") == 0
        || strcmp(command, "backglow on") == 0
        || strcmp(command, "backglow status") == 0;   // Phase 15 (D-19)

    if (!validCommand)
    {
        fprintf(stderr, "Error: Unknown command '%s'\n", command);
        PrintUsage(argv[0]);
        return 1;
    }

    // Connect to driver's named pipe
    HANDLE hPipe = CreateFileA(
        PIPE_NAME,
        GENERIC_READ | GENERIC_WRITE,
        0,          // no sharing
        nullptr,    // default security
        OPEN_EXISTING,
        0,          // default attributes
        nullptr);   // no template

    if (hPipe == INVALID_HANDLE_VALUE)
    {
        DWORD err = GetLastError();
        if (err == ERROR_FILE_NOT_FOUND)
            fprintf(stderr, "Error: Driver pipe not found. Is the Beyond Proximity driver loaded in SteamVR?\n");
        else
            fprintf(stderr, "Error: Cannot connect to driver pipe (error %lu)\n", err);
        return 1;
    }

    // Set pipe to message-read mode (must match server's PIPE_TYPE_MESSAGE).
    // WR-04 (Phase 15 review): surface failure so the user sees a diagnostic
    // instead of silently reading in byte-stream mode (which can truncate
    // multi-line responses like `backglow status`). Non-fatal — continue in
    // byte mode since short single-line responses still work.
    DWORD mode = PIPE_READMODE_MESSAGE;
    if (!SetNamedPipeHandleState(hPipe, &mode, nullptr, nullptr)) {
        fprintf(stderr,
                "Warning: Could not set pipe to message mode (error %lu); "
                "multi-line responses may be truncated\n",
                GetLastError());
        // non-fatal — continue; byte-mode still works for short responses
    }

    // Send command
    DWORD written = 0;
    if (!WriteFile(hPipe, command, (DWORD)strlen(command), &written, nullptr))
    {
        fprintf(stderr, "Error: Failed to send command (error %lu)\n", GetLastError());
        CloseHandle(hPipe);
        return 1;
    }

    // Read response
    char response[1024] = {0};   // Phase 15: multi-line `backglow status` (~200 B nominal, 5x headroom)
    DWORD bytesRead = 0;
    if (ReadFile(hPipe, response, sizeof(response) - 1, &bytesRead, nullptr) && bytesRead > 0)
    {
        response[bytesRead] = '\0';
        printf("%s\n", response);
    }
    else
    {
        fprintf(stderr, "Error: No response from driver (error %lu)\n", GetLastError());
        CloseHandle(hPipe);
        return 1;
    }

    CloseHandle(hPipe);
    return 0;
}