// Take a look at the license at the top of the repository in the LICENSE file.

use crate::auto::functions::parse_bin_from_description;
use glib::prelude::*;
use glib::translate::*;
use std::ptr;

use crate::Bin;
use crate::Element;
use crate::Object;
use crate::ParseContext;
use crate::ParseFlags;

pub fn parse_bin_from_description_with_name(
    bin_description: &str,
    ghost_unlinked_pads: bool,
    bin_name: &str,
) -> Result<Bin, glib::Error> {
    assert_initialized_main_thread!();
    let bin = parse_bin_from_description(bin_description, ghost_unlinked_pads)?;
    if !bin_name.is_empty() {
        let obj = bin.clone().upcast::<Object>();
        unsafe {
            ffi::gst_object_set_name(obj.to_glib_none().0, bin_name.to_glib_none().0);
        }
    }
    Ok(bin)
}

/// This is a convenience wrapper around [`parse_launch()`][crate::parse_launch()] to create a
/// [`Bin`][crate::Bin] from a gst-launch-style pipeline description. See
/// [`parse_launch()`][crate::parse_launch()] and the gst-launch man page for details about the
/// syntax. Ghost pads on the bin for unlinked source or sink pads
/// within the bin can automatically be created (but only a maximum of
/// one ghost pad for each direction will be created; if you expect
/// multiple unlinked source pads or multiple unlinked sink pads
/// and want them all ghosted, you will have to create the ghost pads
/// yourself).
/// ## `bin_description`
/// command line describing the bin
/// ## `ghost_unlinked_pads`
/// whether to automatically create ghost pads
///  for unlinked source or sink pads within the bin
/// ## `context`
/// a parse context allocated with
///  [`ParseContext::new()`][crate::ParseContext::new()], or [`None`]
/// ## `flags`
/// parsing options, or `GST_PARSE_FLAG_NONE`
///
/// # Returns
///
/// a newly-created
///  element, which is guaranteed to be a bin unless
///  [`ParseFlags::NO_SINGLE_ELEMENT_BINS`][crate::ParseFlags::NO_SINGLE_ELEMENT_BINS] was passed, or [`None`] if an error
///  occurred.
#[doc(alias = "gst_parse_bin_from_description_full")]
pub fn parse_bin_from_description_full(
    bin_description: &str,
    ghost_unlinked_pads: bool,
    mut context: Option<&mut ParseContext>,
    flags: ParseFlags,
) -> Result<Element, glib::Error> {
    assert_initialized_main_thread!();
    unsafe {
        let mut error = ptr::null_mut();
        let ret = ffi::gst_parse_bin_from_description_full(
            bin_description.to_glib_none().0,
            ghost_unlinked_pads.into_glib(),
            context.to_glib_none_mut().0,
            flags.into_glib(),
            &mut error,
        );
        if error.is_null() {
            Ok(from_glib_none(ret))
        } else {
            Err(from_glib_full(error))
        }
    }
}

pub fn parse_bin_from_description_with_name_full(
    bin_description: &str,
    ghost_unlinked_pads: bool,
    bin_name: &str,
    context: Option<&mut ParseContext>,
    flags: ParseFlags,
) -> Result<Element, glib::Error> {
    assert_initialized_main_thread!();
    let bin =
        parse_bin_from_description_full(bin_description, ghost_unlinked_pads, context, flags)?;
    if !bin_name.is_empty() {
        let obj = bin.clone().upcast::<Object>();
        unsafe {
            ffi::gst_object_set_name(obj.to_glib_none().0, bin_name.to_glib_none().0);
        }
    }
    Ok(bin)
}

/// Create a new pipeline based on command line syntax.
/// Please note that you might get a return value that is not [`None`] even though
/// the `error` is set. In this case there was a recoverable parsing error and you
/// can try to play the pipeline.
///
/// To create a sub-pipeline (bin) for embedding into an existing pipeline
/// use `gst_parse_bin_from_description_full()`.
/// ## `pipeline_description`
/// the command line describing the pipeline
/// ## `context`
/// a parse context allocated with
///  [`ParseContext::new()`][crate::ParseContext::new()], or [`None`]
/// ## `flags`
/// parsing options, or `GST_PARSE_FLAG_NONE`
///
/// # Returns
///
/// a new element on success, [`None`] on
///  failure. If more than one toplevel element is specified by the
///  `pipeline_description`, all elements are put into a [`Pipeline`][crate::Pipeline], which
///  then is returned (unless the GST_PARSE_FLAG_PLACE_IN_BIN flag is set, in
///  which case they are put in a [`Bin`][crate::Bin] instead).
#[doc(alias = "gst_parse_launch_full")]
pub fn parse_launch_full(
    pipeline_description: &str,
    mut context: Option<&mut ParseContext>,
    flags: ParseFlags,
) -> Result<Element, glib::Error> {
    assert_initialized_main_thread!();
    unsafe {
        let mut error = ptr::null_mut();
        let ret = ffi::gst_parse_launch_full(
            pipeline_description.to_glib_none().0,
            context.to_glib_none_mut().0,
            flags.into_glib(),
            &mut error,
        );
        if error.is_null() {
            Ok(from_glib_none(ret))
        } else {
            Err(from_glib_full(error))
        }
    }
}

/// Create a new element based on command line syntax.
/// `error` will contain an error message if an erroneous pipeline is specified.
/// An error does not mean that the pipeline could not be constructed.
/// ## `argv`
/// null-terminated array of arguments
/// ## `context`
/// a parse context allocated with
///  [`ParseContext::new()`][crate::ParseContext::new()], or [`None`]
/// ## `flags`
/// parsing options, or `GST_PARSE_FLAG_NONE`
///
/// # Returns
///
/// a new element on success; on
///  failure, either [`None`] or a partially-constructed bin or element will be
///  returned and `error` will be set (unless you passed
///  [`ParseFlags::FATAL_ERRORS`][crate::ParseFlags::FATAL_ERRORS] in `flags`, then [`None`] will always be returned
///  on failure)
#[doc(alias = "gst_parse_launchv_full")]
pub fn parse_launchv_full(
    argv: &[&str],
    mut context: Option<&mut ParseContext>,
    flags: ParseFlags,
) -> Result<Element, glib::Error> {
    assert_initialized_main_thread!();
    unsafe {
        let mut error = ptr::null_mut();
        let ret = ffi::gst_parse_launchv_full(
            argv.to_glib_none().0,
            context.to_glib_none_mut().0,
            flags.into_glib(),
            &mut error,
        );
        if error.is_null() {
            Ok(from_glib_none(ret))
        } else {
            Err(from_glib_full(error))
        }
    }
}

/// Calculates the linear regression of the values `xy` and places the
/// result in `m_num`, `m_denom`, `b` and `xbase`, representing the function
///  y(x) = m_num/m_denom * (x - xbase) + b
/// that has the least-square distance from all points `x` and `y`.
///
/// `r_squared` will contain the remaining error.
///
/// If `temp` is not [`None`], it will be used as temporary space for the function,
/// in which case the function works without any allocation at all. If `temp` is
/// [`None`], an allocation will take place. `temp` should have at least the same
/// amount of memory allocated as `xy`, i.e. 2*n*sizeof(GstClockTime).
///
/// > This function assumes (x,y) values with reasonable large differences
/// > between them. It will not calculate the exact results if the differences
/// > between neighbouring values are too small due to not being able to
/// > represent sub-integer values during the calculations.
/// ## `xy`
/// Pairs of (x,y) values
/// ## `temp`
/// Temporary scratch space used by the function
/// ## `n`
/// number of (x,y) pairs
///
/// # Returns
///
/// [`true`] if the linear regression was successfully calculated
///
/// ## `m_num`
/// numerator of calculated slope
///
/// ## `m_denom`
/// denominator of calculated slope
///
/// ## `b`
/// Offset at Y-axis
///
/// ## `xbase`
/// Offset at X-axis
///
/// ## `r_squared`
/// R-squared
#[cfg(any(feature = "v1_12", feature = "dox"))]
#[cfg_attr(feature = "dox", doc(cfg(feature = "v1_12")))]
#[doc(alias = "gst_calculate_linear_regression")]
pub fn calculate_linear_regression(
    xy: &[(u64, u64)],
    temp: Option<&mut [(u64, u64)]>,
) -> Option<(u64, u64, u64, u64, f64)> {
    skip_assert_initialized!();
    use std::mem;

    unsafe {
        assert_eq!(mem::size_of::<u64>() * 2, mem::size_of::<(u64, u64)>());
        assert_eq!(mem::align_of::<u64>(), mem::align_of::<(u64, u64)>());
        assert!(
            temp.as_ref()
                .map(|temp| temp.len())
                .unwrap_or_else(|| xy.len())
                >= xy.len()
        );

        let mut m_num = mem::MaybeUninit::uninit();
        let mut m_denom = mem::MaybeUninit::uninit();
        let mut b = mem::MaybeUninit::uninit();
        let mut xbase = mem::MaybeUninit::uninit();
        let mut r_squared = mem::MaybeUninit::uninit();

        let res = from_glib(ffi::gst_calculate_linear_regression(
            xy.as_ptr() as *const u64,
            temp.map(|temp| temp.as_mut_ptr() as *mut u64)
                .unwrap_or(ptr::null_mut()),
            xy.len() as u32,
            m_num.as_mut_ptr(),
            m_denom.as_mut_ptr(),
            b.as_mut_ptr(),
            xbase.as_mut_ptr(),
            r_squared.as_mut_ptr(),
        ));
        if res {
            Some((
                m_num.assume_init(),
                m_denom.assume_init(),
                b.assume_init(),
                xbase.assume_init(),
                r_squared.assume_init(),
            ))
        } else {
            None
        }
    }
}

/// Checks if `type_` is plugin API. See [`type_mark_as_plugin_api()`][crate::type_mark_as_plugin_api()] for
/// details.
/// ## `type_`
/// a GType
///
/// # Returns
///
/// [`true`] if `type_` is plugin API or [`false`] otherwise.
///
/// ## `flags`
/// What [`PluginAPIFlags`][crate::PluginAPIFlags] the plugin was marked with
#[cfg(any(feature = "v1_18", feature = "dox"))]
#[cfg_attr(feature = "dox", doc(cfg(feature = "v1_18")))]
#[doc(alias = "gst_type_is_plugin_api")]
pub fn type_is_plugin_api(type_: glib::types::Type) -> Option<crate::PluginAPIFlags> {
    assert_initialized_main_thread!();
    unsafe {
        use std::mem;

        let mut flags = mem::MaybeUninit::uninit();
        let ret = from_glib(ffi::gst_type_is_plugin_api(
            type_.into_glib(),
            flags.as_mut_ptr(),
        ));
        let flags = flags.assume_init();
        if ret {
            Some(from_glib(flags))
        } else {
            None
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::prelude::*;

    #[cfg(feature = "v1_12")]
    #[test]
    fn test_calculate_linear_regression() {
        crate::init().unwrap();

        let values = [(0, 0), (1, 1), (2, 2), (3, 3)];

        let (m_num, m_denom, b, xbase, _) = calculate_linear_regression(&values, None).unwrap();
        assert_eq!((m_num, m_denom, b, xbase), (10, 10, 3, 3));

        let mut temp = [(0, 0); 4];
        let (m_num, m_denom, b, xbase, _) =
            calculate_linear_regression(&values, Some(&mut temp)).unwrap();
        assert_eq!((m_num, m_denom, b, xbase), (10, 10, 3, 3));
    }

    #[test]
    fn test_parse_bin_from_description_with_name() {
        crate::init().unwrap();

        let bin =
            parse_bin_from_description_with_name("fakesrc ! fakesink", false, "all_fake").unwrap();
        let name = bin.name();
        assert_eq!(name, "all_fake");

        let bin = parse_bin_from_description_with_name("fakesrc ! fakesink", false, "").unwrap();
        let name = bin.name();
        assert_ne!(name, "");
    }
}