#include <windows.h>

#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>

#include "board/slider-cmd.h"
#include "board/slider-frame.h"

#include "divahook/diva-dll.h"
#include "divahook/slider.h"

#include "hook/iobuf.h"
#include "hook/iohook.h"

#include "hooklib/uart.h"

#include "util/dprintf.h"
#include "util/dump.h"

static HRESULT slider_handle_irp(struct irp *irp);
static HRESULT slider_handle_irp_locked(struct irp *irp);

static HRESULT slider_req_dispatch(const union slider_req_any *req);
static HRESULT slider_req_nop(uint8_t cmd);
static HRESULT slider_req_reset(void);
static HRESULT slider_req_get_board_info(void);
static HRESULT slider_req_auto_scan_start(void);
static HRESULT slider_req_auto_scan_stop(void);
static HRESULT slider_req_set_led(const struct slider_req_set_led *req);

static void slider_res_auto_scan(const uint8_t *pressure);

static CRITICAL_SECTION slider_lock;
static struct uart slider_uart;
static uint8_t slider_written_bytes[520];
static uint8_t slider_readable_bytes[520];

HRESULT slider_hook_init(const struct slider_config *cfg)
{
    assert(cfg != NULL);

    if (!cfg->enable) {
        return S_FALSE;
    }

    InitializeCriticalSection(&slider_lock);

    uart_init(&slider_uart, 11);
    slider_uart.written.bytes = slider_written_bytes;
    slider_uart.written.nbytes = sizeof(slider_written_bytes);
    slider_uart.readable.bytes = slider_readable_bytes;
    slider_uart.readable.nbytes = sizeof(slider_readable_bytes);

    return iohook_push_handler(slider_handle_irp);
}

static HRESULT slider_handle_irp(struct irp *irp)
{
    HRESULT hr;

    assert(irp != NULL);

    if (!uart_match_irp(&slider_uart, irp)) {
        return iohook_invoke_next(irp);
    }

    EnterCriticalSection(&slider_lock);
    hr = slider_handle_irp_locked(irp);
    LeaveCriticalSection(&slider_lock);

    return hr;
}

static HRESULT slider_handle_irp_locked(struct irp *irp)
{
    union slider_req_any req;
    struct iobuf req_iobuf;
    HRESULT hr;

    assert(diva_dll.slider_init != NULL);

    if (irp->op == IRP_OP_OPEN) {
        dprintf("Diva slider: Starting backend DLL\n");
        hr = diva_dll.slider_init();

        if (FAILED(hr)) {
            dprintf("Diva slider: Backend DLL error: %x\n", (int) hr);

            return hr;
        }
    }

    hr = uart_handle_irp(&slider_uart, irp);

    if (FAILED(hr) || irp->op != IRP_OP_WRITE) {
        return hr;
    }

    for (;;) {
#if 0
        dprintf("TX Buffer:\n");
        dump_iobuf(&slider_uart.written);
#endif

        req_iobuf.bytes = req.bytes;
        req_iobuf.nbytes = sizeof(req.bytes);
        req_iobuf.pos = 0;

        hr = slider_frame_decode(&req_iobuf, &slider_uart.written);

        if (hr != S_OK) {
            if (FAILED(hr)) {
                dprintf("Diva slider: Deframe error: %x\n", (int) hr);
            }

            return hr;
        }

#if 0
        dprintf("Deframe Buffer:\n");
        dump_iobuf(&req_iobuf);
#endif

        hr = slider_req_dispatch(&req);

        if (FAILED(hr)) {
            dprintf("Diva slider: Processing error: %x\n", (int) hr);
        }
    }
}

static HRESULT slider_req_dispatch(const union slider_req_any *req)
{
    switch (req->hdr.cmd) {
    case SLIDER_CMD_RESET:
        return slider_req_reset();

    case SLIDER_CMD_GET_BOARD_INFO:
        return slider_req_get_board_info();

    case SLIDER_CMD_AUTO_SCAN_START:
        return slider_req_auto_scan_start();

    case SLIDER_CMD_AUTO_SCAN_STOP:
        return slider_req_auto_scan_stop();

    case SLIDER_CMD_SET_LED:
        return slider_req_set_led(&req->set_led);

    case SLIDER_CMD_DIVA_UNK_09:
    case SLIDER_CMD_DIVA_UNK_0A:
        return slider_req_nop(req->hdr.cmd);

    default:
        dprintf("Unhandled command %02x\n", req->hdr.cmd);

        return S_OK;
    }
}

static HRESULT slider_req_nop(uint8_t cmd)
{
    struct slider_hdr resp;

    dprintf("Diva slider: No-op cmd 0x%#02x\n", cmd);

    resp.sync = SLIDER_FRAME_SYNC;
    resp.cmd = cmd;
    resp.nbytes = 0;

    return slider_frame_encode(&slider_uart.readable, &resp, sizeof(resp));
}

static HRESULT slider_req_reset(void)
{
    struct slider_hdr resp;

    dprintf("Diva slider: Reset\n");

    resp.sync = 0xFF;
    resp.cmd = SLIDER_CMD_RESET;
    resp.nbytes = 0;

    return slider_frame_encode(&slider_uart.readable, &resp, sizeof(resp));
}

static HRESULT slider_req_get_board_info(void)
{
    struct slider_resp_get_board_info resp;

    dprintf("Diva slider: Get firmware version\n");

    memset(&resp, 0, sizeof(resp));
    resp.hdr.sync = SLIDER_FRAME_SYNC;
    resp.hdr.cmd = SLIDER_CMD_GET_BOARD_INFO;
    resp.hdr.nbytes = sizeof(resp.version);

    memset(resp.version, 0, sizeof(resp.version));
    strcpy_s(
            resp.version,
            sizeof(resp.version),
            "15275   \xA0" "06687\xFF" "\x90");

    return slider_frame_encode(&slider_uart.readable, &resp, sizeof(resp));
}

static HRESULT slider_req_auto_scan_start(void)
{
    assert(diva_dll.slider_start != NULL);

    dprintf("Diva slider: Start slider thread\n");
    diva_dll.slider_start(slider_res_auto_scan);

    /* This message is not acknowledged */

    return S_OK;
}

static HRESULT slider_req_auto_scan_stop(void)
{
    struct slider_hdr resp;

    assert(diva_dll.slider_stop != NULL);

    dprintf("Diva slider: Stop slider thread\n");

    /* IO DLL worker thread might attempt to invoke the callback (which needs
       to take slider_lock, which we are currently holding) before noticing that
       it needs to shut down. Unlock here so that we don't deadlock in that
       situation. */

    LeaveCriticalSection(&slider_lock);
    diva_dll.slider_stop();
    EnterCriticalSection(&slider_lock);

    resp.sync = SLIDER_FRAME_SYNC;
    resp.cmd = SLIDER_CMD_AUTO_SCAN_STOP;
    resp.nbytes = 0;

    return slider_frame_encode(&slider_uart.readable, &resp, sizeof(resp));
}

static HRESULT slider_req_set_led(const struct slider_req_set_led *req)
{
    assert(diva_dll.slider_set_leds != NULL);

    /* This message is not acknowledged */
    diva_dll.slider_set_leds(req->payload.rgb);

    return S_OK;
}

static void slider_res_auto_scan(const uint8_t *pressure)
{
    struct slider_resp_auto_scan resp;

    resp.hdr.sync = SLIDER_FRAME_SYNC;
    resp.hdr.cmd = SLIDER_CMD_AUTO_SCAN;
    resp.hdr.nbytes = sizeof(resp.pressure);
    memcpy(resp.pressure, pressure, sizeof(resp.pressure));

    EnterCriticalSection(&slider_lock);
    slider_frame_encode(&slider_uart.readable, &resp, sizeof(resp));
    LeaveCriticalSection(&slider_lock);
}