// Copyright (C) 2016-2017 Sebastian Dröge <sebastian@centricular.com>
//               2016 Luis de Bethencourt <luisbg@osg.samsung.com>
//               2018 François Laignel <fengalin@free.fr>
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use glib;
use glib::subclass;
use glib::subclass::prelude::*;
use gst;
use gst::prelude::*;
use gst::subclass::prelude::*;
use gst_base;
use gst_base::subclass::prelude::*;

use std::fs::File;
use std::io::Write;
use std::sync::Mutex;

use url::Url;

use file_location::FileLocation;

const DEFAULT_LOCATION: Option<FileLocation> = None;

#[derive(Debug)]
struct Settings {
    location: Option<FileLocation>,
}

impl Default for Settings {
    fn default() -> Self {
        Settings {
            location: DEFAULT_LOCATION,
        }
    }
}

const LOCATION_PROP: &str = "location";

static PROPERTIES: [subclass::Property; 1] = [subclass::Property(LOCATION_PROP, || {
    glib::ParamSpec::string(
        LOCATION_PROP,
        "File Location",
        "Location of the file to write",
        None,
        glib::ParamFlags::READWRITE,
    )
})];

enum State {
    Stopped,
    Started { file: File, position: u64 },
}

impl Default for State {
    fn default() -> State {
        State::Stopped
    }
}

pub struct FileSink {
    cat: gst::DebugCategory,
    settings: Mutex<Settings>,
    state: Mutex<State>,
}

impl FileSink {
    fn set_location(
        &self,
        element: &gst_base::BaseSink,
        location: Option<FileLocation>,
    ) -> Result<(), glib::Error> {
        let state = self.state.lock().unwrap();
        if let State::Started { .. } = *state {
            return Err(gst::Error::new(
                gst::LibraryError::Failed,
                format!(
                    "Changing the `{}` property on a started `filesink` is not supported",
                    LOCATION_PROP,
                )
                .as_str(),
            ));
        }

        let mut settings = self.settings.lock().unwrap();
        settings.location = match location {
            Some(location) => {
                match settings.location {
                    Some(ref location_cur) => {
                        gst_info!(
                            self.cat,
                            obj: element,
                            "Changing `{}` from {:?} to {}",
                            LOCATION_PROP,
                            location_cur,
                            location,
                        );
                    }
                    None => {
                        gst_info!(
                            self.cat,
                            obj: element,
                            "Setting `{}` to {}",
                            LOCATION_PROP,
                            location,
                        );
                    }
                }
                Some(location)
            }
            None => {
                gst_info!(
                    self.cat,
                    obj: element,
                    "Resetting `{}` to None",
                    LOCATION_PROP
                );
                None
            }
        };

        Ok(())
    }
}

impl ObjectSubclass for FileSink {
    const NAME: &'static str = "RsFileSink";
    type ParentType = gst_base::BaseSink;
    type Instance = gst::subclass::ElementInstanceStruct<Self>;
    type Class = subclass::simple::ClassStruct<Self>;

    glib_object_subclass!();

    fn new() -> Self {
        Self {
            cat: gst::DebugCategory::new("rsfilesink", gst::DebugColorFlags::empty(), "File Sink"),
            settings: Mutex::new(Default::default()),
            state: Mutex::new(Default::default()),
        }
    }

    fn type_init(type_: &subclass::InitializingType<Self>) {
        gst::subclass::uri_handler::register(type_);
    }

    fn class_init(klass: &mut subclass::simple::ClassStruct<Self>) {
        klass.set_metadata(
            "File Sink",
            "Sink/File",
            "Write stream to a file",
            "François Laignel <fengalin@free.fr>, Luis de Bethencourt <luisbg@osg.samsung.com>",
        );

        let caps = gst::Caps::new_any();
        let sink_pad_template = gst::PadTemplate::new(
            "sink",
            gst::PadDirection::Sink,
            gst::PadPresence::Always,
            &caps,
        );
        klass.add_pad_template(sink_pad_template);

        klass.install_properties(&PROPERTIES);
    }
}

impl ObjectImpl for FileSink {
    glib_object_impl!();

    fn set_property(&self, obj: &glib::Object, id: usize, value: &glib::Value) {
        let prop = &PROPERTIES[id];
        match *prop {
            subclass::Property(LOCATION_PROP, ..) => {
                let element = obj.downcast_ref::<gst_base::BaseSink>().unwrap();

                let res = match value.get::<String>() {
                    Some(location) => FileLocation::try_from_path_str(location)
                        .and_then(|file_location| self.set_location(&element, Some(file_location))),
                    None => self.set_location(&element, None),
                };

                if let Err(err) = res {
                    gst_error!(
                        self.cat,
                        obj: element,
                        "Failed to set property `{}`: {}",
                        LOCATION_PROP,
                        err
                    );
                }
            }
            _ => unimplemented!(),
        };
    }

    fn get_property(&self, _obj: &glib::Object, id: usize) -> Result<glib::Value, ()> {
        let prop = &PROPERTIES[id];
        match *prop {
            subclass::Property(LOCATION_PROP, ..) => {
                let settings = self.settings.lock().unwrap();
                let location = settings
                    .location
                    .as_ref()
                    .map(|location| location.to_string());

                Ok(location.to_value())
            }
            _ => unimplemented!(),
        }
    }
}

impl ElementImpl for FileSink {}

impl BaseSinkImpl for FileSink {
    fn start(&self, element: &gst_base::BaseSink) -> bool {
        let mut state = self.state.lock().unwrap();
        if let State::Started { .. } = *state {
            gst_element_info!(
                element,
                gst::CoreError::StateChange,
                ["FileSink already started"]
            );
            return false;
        }

        let settings = self.settings.lock().unwrap();
        let location = match settings.location {
            Some(ref location) => location,
            None => {
                gst_element_error!(
                    element,
                    gst::ResourceError::Settings,
                    ["File location is not defined"]
                );
                return false;
            }
        };

        let file = match File::create(location) {
            Ok(file) => file,
            Err(err) => {
                gst_element_error!(
                    element,
                    gst::ResourceError::OpenWrite,
                    [
                        "Could not open file {} for writing: {}",
                        location,
                        err.to_string(),
                    ]
                );
                return false;
            }
        };
        gst_debug!(self.cat, obj: element, "Opened file {:?}", file);

        *state = State::Started { file, position: 0 };
        gst_info!(self.cat, obj: element, "Started");

        true
    }

    fn stop(&self, element: &gst_base::BaseSink) -> bool {
        let mut state = self.state.lock().unwrap();
        if let State::Stopped = *state {
            gst_element_warning!(
                element,
                gst::CoreError::StateChange,
                ["FileSink not started"]
            );
            return false;
        }

        *state = State::Stopped;
        gst_info!(self.cat, obj: element, "Stopped");

        true
    }

    // TODO: implement seek in BYTES format

    fn render(&self, element: &gst_base::BaseSink, buffer: &gst::BufferRef) -> gst::FlowReturn {
        let mut state = self.state.lock().unwrap();
        let (file, position) = match *state {
            State::Started {
                ref mut file,
                ref mut position,
            } => (file, position),
            State::Stopped => {
                gst_element_error!(element, gst::CoreError::Failed, ["Not started yet"]);
                return gst::FlowReturn::Error;
            }
        };

        gst_trace!(self.cat, obj: element, "Rendering {:?}", buffer);
        let map = match buffer.map_readable() {
            None => {
                gst_element_error!(element, gst::CoreError::Failed, ["Failed to map buffer"]);
                return gst::FlowReturn::Error;
            }
            Some(map) => map,
        };

        match file.write_all(map.as_ref()) {
            Ok(()) => {
                *position += map.len() as u64;

                gst::FlowReturn::Ok
            }
            Err(err) => {
                gst_element_error!(
                    element,
                    gst::ResourceError::Write,
                    ["Failed to write buffer: {}", err]
                );

                gst::FlowReturn::Error
            }
        }
    }
}

impl URIHandlerImpl for FileSink {
    fn get_uri(&self, _element: &gst::URIHandler) -> Option<String> {
        let settings = self.settings.lock().unwrap();

        // Conversion to Url already checked while building the `FileLocation`
        settings.location.as_ref().map(|location| {
            Url::from_file_path(location)
                .expect("FileSink::get_uri couldn't build `Url` from `location`")
                .into_string()
        })
    }

    fn set_uri(&self, element: &gst::URIHandler, uri: Option<String>) -> Result<(), glib::Error> {
        let element = element.dynamic_cast_ref::<gst_base::BaseSink>().unwrap();

        // Special case for "file://" as this is used by some applications to test
        // with `gst_element_make_from_uri` if there's an element that supports the URI protocol
        let uri = uri.filter(|uri| uri != "file://");

        let file_location = match uri {
            Some(uri) => Some(FileLocation::try_from_uri_str(&uri)?),
            None => None,
        };

        self.set_location(&element, file_location)
    }

    fn get_uri_type() -> gst::URIType {
        gst::URIType::Sink
    }

    fn get_protocols() -> Vec<String> {
        vec!["file".to_string()]
    }
}

pub fn register(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
    gst::Element::register(plugin, "rsfilesink", 256 + 100, FileSink::get_type())
}