use anyhow::Result;
use redb::{Database, TableDefinition};
use std::{
    fs::{File, create_dir_all},
    io::{Read, Write},
    path::{Path, PathBuf},
};

pub enum Cache {
    Directory(PathBuf),
    Redb(Database),
}
const T_DOWNLOAD: TableDefinition<&str, &[u8]> = TableDefinition::new("dl");
impl Cache {
    pub fn new_directory() -> Result<Self> {
        let cachedir = xdg::BaseDirectories::with_prefix("weareearth")
            .unwrap()
            .create_cache_directory("download")
            .unwrap();
        create_dir_all(cachedir.join("BulkMetadata"))?;
        create_dir_all(cachedir.join("NodeData"))?;
        Ok(Self::Directory(cachedir))
    }
    pub fn new_db(path: &Path) -> Result<Self> {
        let db = Database::open(path)?;
        {
            let txn = db.begin_write()?;
            txn.open_table(T_DOWNLOAD)?;
            txn.commit()?;
        }
        Ok(Self::Redb(db))
    }

    pub fn get(&self, path: &str) -> Result<Option<Vec<u8>>> {
        match self {
            Cache::Directory(cachedir) => {
                let cachepath = cachedir.join(path);
                if cachepath.exists() {
                    let mut buf = Vec::new();
                    File::open(cachepath)?.read_to_end(&mut buf)?;
                    Ok(Some(buf.into()))
                } else {
                    Ok(None)
                }
            }
            Cache::Redb(database) => {
                let txn = database.begin_read()?;
                let table = txn.open_table(T_DOWNLOAD)?;
                let res = table.get(path)?;
                if let Some(res) = res {
                    Ok(Some(res.value().to_vec()))
                } else {
                    Ok(None)
                }
            }
        }
    }
    pub fn insert(&self, path: &str, data: &[u8]) -> Result<()> {
        match self {
            Cache::Directory(cachedir) => {
                let cachepath = cachedir.join(path);
                File::create(cachepath)?.write_all(data)?;
                Ok(())
            }
            Cache::Redb(database) => {
                let txn = database.begin_write()?;
                let mut table = txn.open_table(T_DOWNLOAD)?;
                table.insert(path, data)?;
                drop(table);
                txn.commit()?;
                Ok(())
            }
        }
    }
}