use serde::Serialize;
use std::io::{Read, Seek, Write};

use crate::meta::MetaBox;
use crate::mp4box::*;
use crate::mp4box::{mvex::MvexBox, mvhd::MvhdBox, trak::TrakBox, udta::UdtaBox};

#[derive(Debug, Clone, PartialEq, Eq, Default, Serialize)]
pub struct MoovBox {
    pub mvhd: MvhdBox,

    #[serde(skip_serializing_if = "Option::is_none")]
    pub meta: Option<MetaBox>,

    #[serde(skip_serializing_if = "Option::is_none")]
    pub mvex: Option<MvexBox>,

    #[serde(rename = "trak")]
    pub traks: Vec<TrakBox>,

    #[serde(skip_serializing_if = "Option::is_none")]
    pub udta: Option<UdtaBox>,
}

impl MoovBox {
    pub fn get_type(&self) -> BoxType {
        BoxType::MoovBox
    }

    pub fn get_size(&self) -> u64 {
        let mut size = HEADER_SIZE + self.mvhd.box_size();
        for trak in self.traks.iter() {
            size += trak.box_size();
        }
        if let Some(meta) = &self.meta {
            size += meta.box_size();
        }
        if let Some(udta) = &self.udta {
            size += udta.box_size();
        }
        size
    }
}

impl Mp4Box for MoovBox {
    fn box_type(&self) -> BoxType {
        self.get_type()
    }

    fn box_size(&self) -> u64 {
        self.get_size()
    }

    fn to_json(&self) -> Result<String> {
        Ok(serde_json::to_string(&self).unwrap())
    }

    fn summary(&self) -> Result<String> {
        let s = format!("traks={}", self.traks.len());
        Ok(s)
    }
}

impl<R: Read + Seek> ReadBox<&mut R> for MoovBox {
    fn read_box(reader: &mut R, size: u64) -> Result<Self> {
        let start = box_start(reader)?;

        let mut mvhd = None;
        let mut meta = None;
        let mut udta = None;
        let mut mvex = None;
        let mut traks = Vec::new();

        let mut current = reader.stream_position()?;
        let end = start + size;
        while current < end {
            // Get box header.
            let header = BoxHeader::read(reader)?;
            let BoxHeader { name, size: s } = header;
            if s > size {
                return Err(Error::InvalidData(
                    "moov box contains a box with a larger size than it",
                ));
            }

            match name {
                BoxType::MvhdBox => {
                    mvhd = Some(MvhdBox::read_box(reader, s)?);
                }
                BoxType::MetaBox => {
                    meta = Some(MetaBox::read_box(reader, s)?);
                }
                BoxType::MvexBox => {
                    mvex = Some(MvexBox::read_box(reader, s)?);
                }
                BoxType::TrakBox => {
                    let trak = TrakBox::read_box(reader, s)?;
                    traks.push(trak);
                }
                BoxType::UdtaBox => {
                    udta = Some(UdtaBox::read_box(reader, s)?);
                }
                _ => {
                    // XXX warn!()
                    skip_box(reader, s)?;
                }
            }

            current = reader.stream_position()?;
        }

        if mvhd.is_none() {
            return Err(Error::BoxNotFound(BoxType::MvhdBox));
        }

        skip_bytes_to(reader, start + size)?;

        Ok(MoovBox {
            mvhd: mvhd.unwrap(),
            meta,
            udta,
            mvex,
            traks,
        })
    }
}

impl<W: Write> WriteBox<&mut W> for MoovBox {
    fn write_box(&self, writer: &mut W) -> Result<u64> {
        let size = self.box_size();
        BoxHeader::new(self.box_type(), size).write(writer)?;

        self.mvhd.write_box(writer)?;
        for trak in self.traks.iter() {
            trak.write_box(writer)?;
        }
        if let Some(meta) = &self.meta {
            meta.write_box(writer)?;
        }
        if let Some(udta) = &self.udta {
            udta.write_box(writer)?;
        }
        Ok(0)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::mp4box::BoxHeader;
    use std::io::Cursor;

    #[test]
    fn test_moov() {
        let src_box = MoovBox {
            mvhd: MvhdBox::default(),
            mvex: None, // XXX mvex is not written currently
            traks: vec![],
            meta: Some(MetaBox::default()),
            udta: Some(UdtaBox::default()),
        };

        let mut buf = Vec::new();
        src_box.write_box(&mut buf).unwrap();
        assert_eq!(buf.len(), src_box.box_size() as usize);

        let mut reader = Cursor::new(&buf);
        let header = BoxHeader::read(&mut reader).unwrap();
        assert_eq!(header.name, BoxType::MoovBox);
        assert_eq!(header.size, src_box.box_size());

        let dst_box = MoovBox::read_box(&mut reader, header.size).unwrap();
        assert_eq!(dst_box, src_box);
    }

    #[test]
    fn test_moov_empty() {
        let src_box = MoovBox::default();

        let mut buf = Vec::new();
        src_box.write_box(&mut buf).unwrap();
        assert_eq!(buf.len(), src_box.box_size() as usize);

        let mut reader = Cursor::new(&buf);
        let header = BoxHeader::read(&mut reader).unwrap();
        assert_eq!(header.name, BoxType::MoovBox);
        assert_eq!(header.size, src_box.box_size());

        let dst_box = MoovBox::read_box(&mut reader, header.size).unwrap();
        assert_eq!(dst_box, src_box);
    }
}