/* See LICENSE file for copyright and license details. */
#define IN_LIBGAMMA_X_RANDR
#include "common.h"


/**
 * Get the gamma ramp size of a CRTC
 * 
 * @param   this  Instance of a data structure to fill with the information about the CRTC
 * @param   crtc  The state of the CRTC whose information should be read
 * @return        Non-zero on error
 */
static int
get_gamma_ramp_size(struct libgamma_crtc_information *restrict out, struct libgamma_crtc_state *restrict crtc)
{
	xcb_connection_t *restrict connection = crtc->partition->site->data;
	xcb_randr_crtc_t *restrict crtc_id = crtc->data;
	xcb_randr_get_crtc_gamma_size_cookie_t cookie;
	xcb_randr_get_crtc_gamma_size_reply_t *restrict reply;
	xcb_generic_error_t *error;

	/* Query gamma ramp size */
	out->gamma_size_error = 0;
	cookie = xcb_randr_get_crtc_gamma_size(connection, *crtc_id);
	reply = xcb_randr_get_crtc_gamma_size_reply(connection, cookie, &error);
	if (error) {
		out->gamma_size_error = libgamma_x_randr_internal_translate_error(error->error_code,
		                                                                  LIBGAMMA_GAMMA_RAMPS_SIZE_QUERY_FAILED, 1);
		return out->gamma_size_error;
	}
	/* Sanity check gamma ramp size */
	if (reply->size < 2)
		out->gamma_size_error = LIBGAMMA_SINGLETON_GAMMA_RAMP;
	/* Store gamma ramp size */
	out->red_gamma_size = out->green_gamma_size = out->blue_gamma_size = reply->size;
	/* Release resources and return successfulnes */
	free(reply);
	return out->gamma_size_error;
}


/**
 * Read information from the CRTC's output
 * 
 * @param   out     Instance of a data structure to fill with the information about the CRTC
 * @param   output  The CRTC's output information
 * @return          Non-zero if at least on error occured
 */
static int
read_output_data(struct libgamma_crtc_information *restrict out, xcb_randr_get_output_info_reply_t *restrict output)
{
	switch (output->connection) {
	case XCB_RANDR_CONNECTION_CONNECTED:
		/* We have a monitor connected, report that and store information that is provided to us */
		out->active = 1;
		out->width_mm = output->mm_width;
		out->height_mm = output->mm_height;
		switch (output->subpixel_order) {
#define X(CONST, NAME, RENDER_SUFFIX)\
		case XCB_RENDER_SUB_PIXEL_##RENDER_SUFFIX:\
			out->subpixel_order = CONST;\
			break;
		LIST_SUBPIXEL_ORDERS(X)
#undef X
		default:
			out->subpixel_order_error = LIBGAMMA_SUBPIXEL_ORDER_NOT_RECOGNISED;
			break;
		}
		return 0;

	case XCB_RANDR_CONNECTION_UNKNOWN:
		/* If we do know whether a monitor is connected report that and assume it is not */
		out->active_error = LIBGAMMA_STATE_UNKNOWN;
		/* fall through */
	default:
		/* If no monitor is connected, report that on fails that require it */
		out->width_mm_error       = LIBGAMMA_NOT_CONNECTED;
		out->height_mm_error      = LIBGAMMA_NOT_CONNECTED;
		out->subpixel_order_error = LIBGAMMA_NOT_CONNECTED;
		/* And store that we are not connected */
		out->active = 0;
		/* This fuction only failed if we could not figure out whether a monitor is connected */
		return output->connection != XCB_RANDR_CONNECTION_UNKNOWN ? 0 : -1;
	}
}


/**
 * Determine the connector type from the connector name
 * 
 * @param  this  The CRTC information to use and extend
 * @param        Non-zero on error
 */
static int
get_connector_type(struct libgamma_crtc_information *restrict this)
{
	/* Since we require the name of the output of get the type of the connected,
	 * copy any reported error on the output's name to the connector's type,
	 * and report failure if there was an error */
	if ((this->connector_type_error = this->connector_name_error))
		return -1;

#define SELECT(name, type)\
	do {\
		if (strstr(this->connector_name, name "-") == this->connector_name) {\
			this->connector_type = LIBGAMMA_CONNECTOR_TYPE_##type;\
			return 0;\
		}\
	} while (0)

	/* Check begin on the name of the output to find out what type the connector is of */
	SELECT ("None",        Unknown);
	SELECT ("VGA",         VGA);
	SELECT ("DVI-I",       DVII);
	SELECT ("DVI-D",       DVID);
	SELECT ("DVI-A",       DVIA);
	SELECT ("DVI",         DVI);
	SELECT ("Composite",   Composite);
	SELECT ("S-Video",     SVIDEO);
	SELECT ("Component",   Component);
	SELECT ("LFP",         LFP);
	SELECT ("Proprietary", Unknown);
	SELECT ("HDMI",        HDMI);
	SELECT ("DisplayPort", DisplayPort);

#undef SELECT

	/* If there was no matching output name pattern report that and exit with an error */
	this->connector_name_error = LIBGAMMA_CONNECTOR_TYPE_NOT_RECOGNISED;
	return -1;
}


/**
 * Get the output name of a CRTC
 * 
 * @param   this    Instance of a data structure to fill with the information about the CRTC
 * @param   output  The CRTC's output's information
 * @return          Non-zero on error
 */
static int
get_output_name(struct libgamma_crtc_information *restrict out, xcb_randr_get_output_info_reply_t *restrict output)
{
	char *restrict store;
	uint8_t *restrict name;
	uint16_t length;
	size_t i;

	/* Get the name of the output and the length of that name */
	name = xcb_randr_get_output_info_name(output);
	length = output->name_len; /* There is no NUL-termination */
	if (!name)
		return out->connector_name_error = LIBGAMMA_REPLY_VALUE_EXTRACTION_FAILED;

	/* Allocate a memory area for a NUL-terminated copy of the name */
	store = out->connector_name = malloc(((size_t)length + 1) * sizeof(char));
	if (!store) {
		out->connector_name_error = errno;
		return -1;
	}

	/* char is guaranteed to be (u)int_least8_t, but it is only guaranteed to be (u)int8_t
	 * on POSIX, so to be truly portable we will not assume that char is (u)int8_t */
	for (i = 0; i < (size_t)length; i++)
		store[i] = (char)name[i];
	store[length] = '\0';

	return 0;
}


/**
 * Get the Extended Display Information Data of the monitor connected to the connector of a CRTC
 * 
 * @param   out     Instance of a data structure to fill with the information about the CRTC
 * @param   crtc    The state of the CRTC whose information should be read
 * @param   output  The CRTC's output
 * @return          Non-zero on error
 */
static int
get_edid(struct libgamma_crtc_information *restrict out, struct libgamma_crtc_state *restrict crtc, xcb_randr_output_t output)
{
	xcb_connection_t *restrict connection = crtc->partition->site->data;
	xcb_randr_list_output_properties_cookie_t prop_cookie;
	xcb_randr_list_output_properties_reply_t *restrict prop_reply;
	xcb_atom_t *atoms;
	xcb_atom_t *atoms_end;
	xcb_generic_error_t *error;
	xcb_get_atom_name_cookie_t atom_name_cookie;
	xcb_get_atom_name_reply_t *restrict atom_name_reply;
	char *restrict atom_name;
	int atom_name_len;
	xcb_randr_get_output_property_cookie_t atom_cookie;
	xcb_randr_get_output_property_reply_t *restrict atom_reply;
	unsigned char *restrict atom_data;
	int length;

	/* Acquire a list of all properties of the output */
	prop_cookie = xcb_randr_list_output_properties(connection, output);
	prop_reply = xcb_randr_list_output_properties_reply(connection, prop_cookie, &error);
	if (error) {
		return out->edid_error = libgamma_x_randr_internal_translate_error(error->error_code,
		                                                                   LIBGAMMA_LIST_PROPERTIES_FAILED, 1);
	}
  
	/* Extract the properties form the data structure that holds them, */
	atoms = xcb_randr_list_output_properties_atoms(prop_reply);
	/* and get the last one so that we can iterate over them nicely */
	atoms_end = atoms + xcb_randr_list_output_properties_atoms_length(prop_reply);

	if (!atoms) {
		free(prop_reply);
		return out->edid_error = LIBGAMMA_REPLY_VALUE_EXTRACTION_FAILED;
	}

	/* For each property */
	for (; atoms != atoms_end; atoms++) {
		/* Acquire the atom name */
		atom_name_cookie = xcb_get_atom_name(connection, *atoms);
		atom_name_reply = xcb_get_atom_name_reply(connection, atom_name_cookie, &error);
		if (error)
			continue;

		/* Extract the atom name from the data structure that holds it */
		atom_name = xcb_get_atom_name_name(atom_name_reply);
		/* As well as the length of the name; it is not NUL-termianted */
		atom_name_len = xcb_get_atom_name_name_length(atom_name_reply);

		if (/* Check for errors */
		    !atom_name || /* atom_name_len < 1 || */
		    /* Check that the length is the expected length for the EDID property */
		    atom_name_len != 4 ||
		    /* Check that the property is the EDID property */
		    atom_name[0] != 'E' || atom_name[1] != 'D' || atom_name[2] != 'I' || atom_name[3] != 'D') {
			free(atom_name_reply);
			continue;
		}

		/* Acquire the property's value, we know that it is either 128 or 256 byte long */
		atom_cookie = xcb_randr_get_output_property(connection, output, *atoms, XCB_GET_PROPERTY_TYPE_ANY, 0, 256, 0, 0);
		atom_reply = xcb_randr_get_output_property_reply(connection, atom_cookie, &error);
		/* (*) EDID version 1.0 through 1.4 define it as 128 bytes long,
		 * but version 2.0 define it as 256 bytes long. However,
		 * version 2.0 is rare(?) and has been deprecated and replaced
		 * by version 1.3 (I guess that is with a new version epoch,
		 * but I do not know.) */
		if (error) {
			free(atom_name_reply);
			free(prop_reply);
			return out->edid_error = LIBGAMMA_PROPERTY_VALUE_QUERY_FAILED;
		}

		/* Extract the property's value */
		atom_data = xcb_randr_get_output_property_data(atom_reply);
		/* and its actual length */
		length = xcb_randr_get_output_property_data_length(atom_reply);
		if (!atom_data || length < 1) {
			free(atom_reply);
			free(atom_name_reply);
			free(prop_reply);
			return out->edid_error = LIBGAMMA_REPLY_VALUE_EXTRACTION_FAILED;
		}

		/* Store the EDID */
		out->edid_length = (size_t)length;
		out->edid = malloc((size_t)length * sizeof(unsigned char));
		if (!out->edid)
			out->edid_error = errno;
		else
			memcpy(out->edid, atom_data, (size_t)length * sizeof(unsigned char));

		/* Release resouces */
		free(atom_reply);
		free(atom_name_reply);
		free(prop_reply);

		return out->edid_error;
	}

	return out->edid_error = LIBGAMMA_EDID_NOT_FOUND;
}


/**
 * Read information about a CRTC
 * 
 * @param   this    Instance of a data structure to fill with the information about the CRTC
 * @param   crtc    The state of the CRTC whose information should be read
 * @param   fields  OR:ed identifiers for the information about the CRTC that should be read
 * @return          Zero on success, -1 on error; on error refer to the error reports in `this`
 */
int
libgamma_x_randr_get_crtc_information(struct libgamma_crtc_information *restrict this,
                                      struct libgamma_crtc_state *restrict crtc, unsigned long long fields)
{
#define _E(FIELD) ((fields & FIELD) ? LIBGAMMA_CRTC_INFO_NOT_SUPPORTED : 0)

	int e = 0;
	xcb_randr_get_output_info_reply_t *restrict output_info = NULL;
	xcb_randr_output_t output;
	int free_edid, free_name;
	xcb_connection_t *restrict connection;
	struct libgamma_x_randr_partition_data *restrict screen_data;
	size_t output_index;
	xcb_randr_get_output_info_cookie_t cookie;
	xcb_generic_error_t *error;

	/* Wipe all error indicators */
	memset(this, 0, sizeof(*this));

	/* We need to free the EDID after us if it is not explicitly requested */
	free_edid = !(fields & LIBGAMMA_CRTC_INFO_EDID);

	/* We need to free the output's name after us if it is not explicitly requested */
	free_name = !(fields & LIBGAMMA_CRTC_INFO_CONNECTOR_NAME);

	/* Jump if the output information is not required */
	if (!(fields & (LIBGAMMA_CRTC_INFO_MACRO_ACTIVE | LIBGAMMA_CRTC_INFO_MACRO_CONNECTOR)))
		goto cont;

	/* Get connector and connector information */
	connection = crtc->partition->site->data;
	screen_data = crtc->partition->data;
	output_index = screen_data->crtc_to_output[crtc->crtc];
	/* `SIZE_MAX` is used for CRTC:s that misses mapping to its output (should not happen),
	 * because `SIZE_MAX - 1` is the highest theoretical possible value */
	if (output_index == SIZE_MAX) {
		e |= this->edid_error = this->gamma_error = this->width_mm_edid_error
		   = this->height_mm_edid_error = this->connector_type_error
		   = this->connector_name_error = this->subpixel_order_error
		   = this->width_mm_error = this->height_mm_error
		   = this->active_error = LIBGAMMA_CONNECTOR_UNKNOWN;
		goto cont;
	}
	/* Get the output */
	output = screen_data->outputs[output_index];
	/* Query output information */
	cookie = xcb_randr_get_output_info(connection, output, screen_data->config_timestamp);
	output_info = xcb_randr_get_output_info_reply(connection, cookie, &error);
	if (error) {
		e |= this->edid_error = this->gamma_error = this->width_mm_edid_error
		   = this->height_mm_edid_error = this->connector_type_error
		   = this->connector_name_error = this->subpixel_order_error
		   = this->width_mm_error = this->height_mm_error
		   = this->active_error = LIBGAMMA_OUTPUT_INFORMATION_QUERY_FAILED;
		goto cont;
	}

	/* Get connector name */
	e |= get_output_name(this, output_info);
	/* Get connector type */
	if (fields & LIBGAMMA_CRTC_INFO_CONNECTOR_TYPE)
		e |= get_connector_type(this);
	/* Get additional output data, excluding EDID */
	e |= read_output_data(this, output_info);
	if (fields & LIBGAMMA_CRTC_INFO_MACRO_VIEWPORT)
		e |= this->width_mm_error | this->height_mm_error;
	e |= (fields & LIBGAMMA_CRTC_INFO_SUBPIXEL_ORDER) ? this->subpixel_order_error : 0;

	/* If we do not want any EDID information, jump */
	if (!(fields & LIBGAMMA_CRTC_INFO_MACRO_EDID))
		goto cont;
	/* If there is not monitor that report error in EDID related fields */
	if (!this->active) {
		e |= this->edid_error = this->gamma_error = this->width_mm_edid_error
		   = this->height_mm_edid_error = LIBGAMMA_NOT_CONNECTED;
		goto cont;
	}
	/* Get EDID */
	e |= get_edid(this, crtc, output);
	if (!this->edid) {
		this->gamma_error = this->width_mm_edid_error = this->height_mm_edid_error = this->edid_error;
		goto cont;
	}
	/* Parse EDID */
	if ((fields & (LIBGAMMA_CRTC_INFO_MACRO_EDID ^ LIBGAMMA_CRTC_INFO_EDID)))
		e |= libgamma_internal_parse_edid(this, fields);

cont:
	/* Get gamma ramp size */
	e |= (fields & LIBGAMMA_CRTC_INFO_GAMMA_SIZE) ? get_gamma_ramp_size(this, crtc) : 0;
	/* Store gamma ramp depth. */
	this->gamma_depth = 16;
	/* X RandR does not support quering gamma ramp support. */
	e |= this->gamma_support_error = _E(LIBGAMMA_CRTC_INFO_GAMMA_SUPPORT);

	/* Free the EDID after us */
	if (free_edid) {
		free(this->edid);
		this->edid = NULL;
	}
	/* Free the output name after us */
	if (free_name) {
		free(this->connector_name);
		this->connector_name = NULL;
	}

	free(output_info);
	return e ? -1 : 0;

#undef _E
}