#include "displayserver_linux.h"
#include "common/io.h"
#include "common/edidHelper.h"
#include "common/stringUtils.h"

#ifdef __linux__
    #include <dirent.h>

static const char* drmParseSysfs(FFDisplayServerResult* result) {
    const char* drmDirPath = "/sys/class/drm/";

    FF_AUTO_CLOSE_DIR DIR* dirp = opendir(drmDirPath);
    if (dirp == NULL) {
        return "opendir(drmDirPath) failed";
    }

    FF_STRBUF_AUTO_DESTROY drmDir = ffStrbufCreateA(64);
    ffStrbufAppendS(&drmDir, drmDirPath);

    uint32_t drmDirLength = drmDir.length;

    struct dirent* entry;
    while ((entry = readdir(dirp)) != NULL) {
        if (entry->d_name[0] == '.') {
            continue;
        }

        ffStrbufAppendS(&drmDir, entry->d_name);
        uint32_t drmDirWithDnameLength = drmDir.length;

        char buf;
        ffStrbufAppendS(&drmDir, "/enabled");
        if (ffReadFileData(drmDir.chars, sizeof(buf), &buf) <= 0 || buf != 'e') {
            /* read failed or enabled != "enabled" */
            ffStrbufSubstrBefore(&drmDir, drmDirWithDnameLength);
            ffStrbufAppendS(&drmDir, "/status");
            buf = 'd';
            ffReadFileData(drmDir.chars, sizeof(buf), &buf);
            if (buf != 'c') {
                /* read failed or status != "connected" */
                ffStrbufSubstrBefore(&drmDir, drmDirLength);
                continue;
            }
        }

        unsigned width = 0, height = 0, physicalWidth = 0, physicalHeight = 0;
        double refreshRate = 0;
        FF_STRBUF_AUTO_DESTROY name = ffStrbufCreate();

        ffStrbufSubstrBefore(&drmDir, drmDirWithDnameLength);
        ffStrbufAppendS(&drmDir, "/edid");

        const char* plainName = entry->d_name;
        if (ffStrStartsWith(plainName, "card")) {
            const char* tmp = strchr(plainName + strlen("card"), '-');
            if (tmp) {
                plainName = tmp + 1;
            }
        }

        uint8_t edidData[512];
        ssize_t edidLength = ffReadFileData(drmDir.chars, ARRAY_SIZE(edidData), edidData);
        if (edidLength <= 0 || edidLength % 128 != 0) {
            edidLength = 0;
            ffStrbufSubstrBefore(&drmDir, drmDirWithDnameLength);
            ffStrbufAppendS(&drmDir, "/modes");

            char modes[32];
            if (ffReadFileData(drmDir.chars, ARRAY_SIZE(modes), modes) >= 3) {
                sscanf(modes, "%ux%u", &width, &height);
                ffStrbufAppendS(&name, plainName);
            }
        } else {
            ffEdidGetName(edidData, &name);
            ffEdidGetPreferredResolutionAndRefreshRate(edidData, &width, &height, &refreshRate);
            ffEdidGetPhysicalSize(edidData, &physicalWidth, &physicalHeight);
        }

        FFDisplayResult* item = ffdsAppendDisplay(
            result,
            width,
            height,
            refreshRate,
            0,
            0,
            0,
            0,
            0,
            &name,
            ffdsGetDisplayType(plainName),
            false,
            0,
            physicalWidth,
            physicalHeight,
            "sysfs-drm");
        if (item && edidLength) {
            item->hdrStatus = ffEdidGetHdrCompatible(edidData, (uint32_t) edidLength) ? FF_DISPLAY_HDR_STATUS_SUPPORTED : FF_DISPLAY_HDR_STATUS_UNSUPPORTED;
            ffEdidGetSerialAndManufactureDate(edidData, &item->serial, &item->manufactureYear, &item->manufactureWeek);
        }

        ffStrbufSubstrBefore(&drmDir, drmDirLength);
    }

    return NULL;
}
#endif

#ifdef FF_HAVE_DRM

    #include "common/library.h"

    #include <xf86drm.h>
    #include <xf86drmMode.h>
    #include <fcntl.h>

// https://gitlab.freedesktop.org/mesa/drm/-/blob/main/xf86drmMode.c#L1785
// It's not supported on Ubuntu 20.04
static inline const char* drmType2Name(uint32_t connector_type) {
    /* Keep the strings in sync with the kernel's drm_connector_enum_list in
     * drm_connector.c. */
    switch (connector_type) {
        case DRM_MODE_CONNECTOR_Unknown:
            return "Unknown";
        case DRM_MODE_CONNECTOR_VGA:
            return "VGA";
        case DRM_MODE_CONNECTOR_DVII:
            return "DVI-I";
        case DRM_MODE_CONNECTOR_DVID:
            return "DVI-D";
        case DRM_MODE_CONNECTOR_DVIA:
            return "DVI-A";
        case DRM_MODE_CONNECTOR_Composite:
            return "Composite";
        case DRM_MODE_CONNECTOR_SVIDEO:
            return "SVIDEO";
        case DRM_MODE_CONNECTOR_LVDS:
            return "LVDS";
        case DRM_MODE_CONNECTOR_Component:
            return "Component";
        case DRM_MODE_CONNECTOR_9PinDIN:
            return "DIN";
        case DRM_MODE_CONNECTOR_DisplayPort:
            return "DP";
        case DRM_MODE_CONNECTOR_HDMIA:
            return "HDMI-A";
        case DRM_MODE_CONNECTOR_HDMIB:
            return "HDMI-B";
        case DRM_MODE_CONNECTOR_TV:
            return "TV";
        case DRM_MODE_CONNECTOR_eDP:
            return "eDP";
        case DRM_MODE_CONNECTOR_VIRTUAL:
            return "Virtual";
        case DRM_MODE_CONNECTOR_DSI:
            return "DSI";
        case DRM_MODE_CONNECTOR_DPI:
            return "DPI";
        case DRM_MODE_CONNECTOR_WRITEBACK:
            return "Writeback";
        case 19 /*DRM_MODE_CONNECTOR_SPI*/:
            return "SPI";
        case 20 /*DRM_MODE_CONNECTOR_USB*/:
            return "USB";
        default:
            return "Unsupported";
    }
}

FF_A_UNUSED static const char* drmGetEdidByConnId(uint32_t connId, uint8_t* edidData, ssize_t* edidLength) {
    const char* drmDirPath = "/sys/class/drm/";

    FF_AUTO_CLOSE_DIR DIR* dirp = opendir(drmDirPath);
    if (dirp == NULL) {
        return "opendir(drmDirPath) failed";
    }

    FF_STRBUF_AUTO_DESTROY drmDir = ffStrbufCreateA(64);
    ffStrbufAppendS(&drmDir, drmDirPath);

    uint32_t drmDirLength = drmDir.length;

    struct dirent* entry;
    while ((entry = readdir(dirp)) != NULL) {
        if (entry->d_name[0] == '.') {
            continue;
        }

        ffStrbufAppendS(&drmDir, entry->d_name);
        uint32_t drmDirWithDnameLength = drmDir.length;

        char connectorId[16] = {};

        ffStrbufAppendS(&drmDir, "/connector_id");
        ffReadFileData(drmDir.chars, ARRAY_SIZE(connectorId), connectorId);
        if (strtoul(connectorId, NULL, 10) != connId) {
            ffStrbufSubstrBefore(&drmDir, drmDirLength);
            continue;
        }

        ffStrbufSubstrBefore(&drmDir, drmDirWithDnameLength);
        ffStrbufAppendS(&drmDir, "/edid");
        *edidLength = ffReadFileData(drmDir.chars, (uint32_t) *edidLength, edidData);
        return NULL;
    }

    return "Failed to match connector ID";
}

static const char* drmConnectLibdrm(FFDisplayServerResult* result) {
    FF_LIBRARY_LOAD_MESSAGE(libdrm, "libdrm" FF_LIBRARY_EXTENSION, 2)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmGetDevices)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeGetResources)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeGetConnectorCurrent)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeGetCrtc)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeGetEncoder)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeGetFB)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeGetProperty)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeGetPropertyBlob)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeFreeResources)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeFreeCrtc)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeFreeConnector)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeFreeEncoder)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeFreeFB)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeFreeProperty)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmModeFreePropertyBlob)
    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libdrm, drmFreeDevices)

    drmDevice* devices[64];
    int nDevices = ffdrmGetDevices(devices, ARRAY_SIZE(devices));
    if (nDevices <= 0) {
        return "drmGetDevices() failed";
    }

    FF_STRBUF_AUTO_DESTROY name = ffStrbufCreate();

    for (int iDev = 0; iDev < nDevices; ++iDev) {
        drmDevice* dev = devices[iDev];

        if (!(dev->available_nodes & (1 << DRM_NODE_PRIMARY))) {
            continue;
        }

        const char* path = dev->nodes[DRM_NODE_PRIMARY];

    #if __linux__
        ffStrbufSetF(&name, "/sys/class/drm/%s/device/power/runtime_status", strrchr(path, '/') + 1);

        char buffer[8] = "";
        if (ffReadFileData(name.chars, strlen("suspend"), buffer) > 0 && ffStrStartsWith(buffer, "suspend")) {
            continue;
        }
    #endif

        FF_AUTO_CLOSE_FD int primaryFd = open(path, O_RDWR | O_CLOEXEC);
        if (primaryFd < 0) {
            continue;
        }

        drmModeRes* res = ffdrmModeGetResources(primaryFd);
        if (!res) {
            continue;
        }

        for (int iConn = 0; iConn < res->count_connectors; ++iConn) {
            drmModeConnector* conn = ffdrmModeGetConnectorCurrent(primaryFd, res->connectors[iConn]);
            if (!conn) {
                continue;
            }

            if (conn->connection != DRM_MODE_DISCONNECTED) {
                drmModeEncoder* encoder = ffdrmModeGetEncoder(primaryFd, conn->encoder_id);
                uint32_t width = 0, height = 0, refreshRate = 0;
                uint8_t bitDepth = 0;

                if (encoder) {
                    drmModeCrtc* crtc = ffdrmModeGetCrtc(primaryFd, encoder->crtc_id);
                    if (crtc) {
                        width = crtc->mode.hdisplay;
                        height = crtc->mode.vdisplay;
                        refreshRate = crtc->mode.vrefresh;
                        if (refreshRate == 0) {
                            // There are weird cases that we can't get the refresh rate from the CRTC but from the modes
                            for (int iMode = 0; iMode < conn->count_modes; ++iMode) {
                                drmModeModeInfo* mode = &conn->modes[iMode];
                                if (mode->clock == crtc->mode.clock && mode->htotal == crtc->mode.htotal) {
                                    refreshRate = mode->vrefresh;
                                    break;
                                }
                            }
                        }

                        drmModeFBPtr fb = ffdrmModeGetFB(primaryFd, crtc->buffer_id);
                        if (fb) {
                            bitDepth = (uint8_t) (fb->depth / 3);
                            ffdrmModeFreeFB(fb);
                        }

                        ffdrmModeFreeCrtc(crtc);
                    }

                    ffdrmModeFreeEncoder(encoder);
                }

                uint32_t preferredWidth = 0, preferredHeight = 0, preferredRefreshRate = 0;

                for (int iMode = 0; iMode < conn->count_modes; ++iMode) {
                    drmModeModeInfo* mode = &conn->modes[iMode];

                    if (mode->type & DRM_MODE_TYPE_PREFERRED) {
                        preferredWidth = mode->hdisplay;
                        preferredHeight = mode->vdisplay;
                        preferredRefreshRate = mode->vrefresh;
                        break;
                    }
                }

                // NVIDIA DRM driver seems incomplete and conn->encoder_id == 0
                // Assume preferred resolution is used as what we do in drmParseSys
                if (width == 0 || height == 0) {
                    width = preferredWidth;
                    height = preferredHeight;
                    refreshRate = preferredRefreshRate;
                }

                ffStrbufClear(&name);
                uint16_t myear = 0, mweak = 0;
                uint32_t serial = 0;
                FFDisplayHdrStatus hdrStatus = FF_DISPLAY_HDR_STATUS_UNKNOWN;

                for (int iProp = 0; iProp < conn->count_props; ++iProp) {
                    drmModePropertyRes* prop = ffdrmModeGetProperty(primaryFd, conn->props[iProp]);
                    if (!prop) {
                        continue;
                    }

                    uint32_t type = prop->flags & (DRM_MODE_PROP_LEGACY_TYPE | DRM_MODE_PROP_EXTENDED_TYPE);
                    if (type == DRM_MODE_PROP_BLOB && ffStrEquals(prop->name, "EDID")) {
                        drmModePropertyBlobPtr blob = NULL;

                        if (prop->count_blobs > 0 && prop->blob_ids != NULL) {
                            blob = ffdrmModeGetPropertyBlob(primaryFd, prop->blob_ids[0]);
                        } else {
                            blob = ffdrmModeGetPropertyBlob(primaryFd, (uint32_t) conn->prop_values[iProp]);
                        }

                        if (blob) {
                            if (blob->length >= 128) {
                                ffEdidGetName(blob->data, &name);
                                hdrStatus = ffEdidGetHdrCompatible(blob->data, blob->length) ? FF_DISPLAY_HDR_STATUS_SUPPORTED : FF_DISPLAY_HDR_STATUS_UNSUPPORTED;
                                ffEdidGetSerialAndManufactureDate(blob->data, &serial, &myear, &mweak);
                            }
                            ffdrmModeFreePropertyBlob(blob);
                        }
                        break;
                    }
                    ffdrmModeFreeProperty(prop);
                }

    #if __linux__
                if (name.length == 0) {
                    uint8_t edidData[512];
                    ssize_t edidLength = 0;
                    drmGetEdidByConnId(conn->connector_id, edidData, &edidLength);
                    if (edidLength > 0 && edidLength % 128 == 0) {
                        ffEdidGetName(edidData, &name);
                        hdrStatus = ffEdidGetHdrCompatible(edidData, (uint32_t) edidLength) ? FF_DISPLAY_HDR_STATUS_SUPPORTED : FF_DISPLAY_HDR_STATUS_UNSUPPORTED;
                        ffEdidGetSerialAndManufactureDate(edidData, &serial, &myear, &mweak);
                    }
                }
    #endif

                if (name.length == 0) {
                    const char* connectorTypeName = drmType2Name(conn->connector_type);
                    if (connectorTypeName == NULL) {
                        connectorTypeName = "Unknown";
                    }
                    ffStrbufSetF(&name, "%s-%d", connectorTypeName, iConn + 1);
                }

                FFDisplayResult* item = ffdsAppendDisplay(result,
                    width,
                    height,
                    refreshRate,
                    0,
                    preferredWidth,
                    preferredHeight,
                    preferredRefreshRate,
                    0,
                    &name,
                    conn->connector_type == DRM_MODE_CONNECTOR_eDP || conn->connector_type == DRM_MODE_CONNECTOR_LVDS
                        ? FF_DISPLAY_TYPE_BUILTIN
                        : conn->connector_type == DRM_MODE_CONNECTOR_HDMIA || conn->connector_type == DRM_MODE_CONNECTOR_HDMIB || conn->connector_type == DRM_MODE_CONNECTOR_DisplayPort
                        ? FF_DISPLAY_TYPE_EXTERNAL
                        : FF_DISPLAY_TYPE_UNKNOWN,
                    false,
                    conn->connector_id,
                    conn->mmWidth,
                    conn->mmHeight,
                    "libdrm");

                if (item) {
                    item->hdrStatus = hdrStatus;
                    item->serial = serial;
                    item->manufactureYear = myear;
                    item->manufactureWeek = mweak;
                    item->bitDepth = bitDepth;
                }
            }

            ffdrmModeFreeConnector(conn);
        }

        ffdrmModeFreeResources(res);
    }

    ffdrmFreeDevices(devices, nDevices);

    return NULL;
}

#endif

const char* ffdsConnectDrm(FF_A_UNUSED FFDisplayServerResult* result) {
#ifdef FF_HAVE_DRM
    if (instance.config.general.dsForceDrm != FF_DS_FORCE_DRM_TYPE_SYSFS_ONLY) {
        if (drmConnectLibdrm(result) == NULL) {
            return NULL;
        }
    }
#endif

#ifdef __linux__
    return drmParseSysfs(result);
#endif

    return "fastfetch was compiled without drm support";
}
