use crate::{
    object::{Value, parser::FromValue},
    unityfs::UnityFS,
};
use anyhow::{Result, anyhow, bail};
use serde::Serialize;
use std::io::{Read, Seek, SeekFrom};

#[derive(Debug, Serialize)]
pub struct StreamedResource {
    pub offset: u64,
    pub size: u64,
    pub path: String,
}

impl FromValue for StreamedResource {
    fn from_value(v: Value) -> Result<Self> {
        let mut fields = v.as_class("StreamedResource")?;
        Ok(StreamedResource {
            offset: fields.field("m_Offset")?,
            size: fields.field("m_Size")?,
            path: fields.field("m_Source")?,
        })
    }
}

impl StreamedResource {
    pub fn read(&self, fs: &UnityFS<impl Read + Seek>) -> Result<Vec<u8>> {
        if !self.path.starts_with("archive:") {
            bail!(
                "StreamedResource path does not start on 'archive:' ({:?})",
                self.path
            )
        }
        let nodeinfo = fs
            .header
            .nodes()
            .iter()
            .find(|n| self.path.ends_with(&n.name))
            .ok_or(anyhow!("node with path {:?} not found", self.path))?
            .to_owned();

        let mut buf = Vec::new();

        let mut node = fs.read(&nodeinfo)?;
        node.seek(SeekFrom::Start(self.offset))?;
        node.take(self.size).read_to_end(&mut buf)?;
        Ok(buf)
    }
}