use {
    serde::{Deserialize, Serialize},
    solana_config_program::ConfigState,
    solana_sdk::{
        hash::Hash,
        pubkey::Pubkey,
        signature::{Signable, Signature},
    },
    std::{borrow::Cow, error, io},
};

/// Information required to download and apply a given update
#[derive(Serialize, Deserialize, Default, Clone, Debug, PartialEq)]
pub struct UpdateManifest {
    pub timestamp_secs: u64, // When the release was deployed in seconds since UNIX EPOCH
    pub download_url: String, // Download URL to the release tar.bz2
    pub download_sha256: Hash, // SHA256 digest of the release tar.bz2 file
}

/// Data of an Update Manifest program Account.
#[derive(Serialize, Deserialize, Default, Debug, PartialEq)]
pub struct SignedUpdateManifest {
    pub manifest: UpdateManifest,
    pub manifest_signature: Signature,
    #[serde(skip)]
    pub account_pubkey: Pubkey,
}

impl Signable for SignedUpdateManifest {
    fn pubkey(&self) -> Pubkey {
        self.account_pubkey
    }

    fn signable_data(&self) -> Cow<[u8]> {
        Cow::Owned(bincode::serialize(&self.manifest).expect("serialize"))
    }
    fn get_signature(&self) -> Signature {
        self.manifest_signature
    }
    fn set_signature(&mut self, signature: Signature) {
        self.manifest_signature = signature
    }
}

impl SignedUpdateManifest {
    pub fn deserialize(
        account_pubkey: &Pubkey,
        input: &[u8],
    ) -> Result<Self, Box<dyn error::Error>> {
        let mut manifest: SignedUpdateManifest = bincode::deserialize(input)?;
        manifest.account_pubkey = *account_pubkey;
        if !manifest.verify() {
            Err(io::Error::new(io::ErrorKind::Other, "Manifest failed to verify").into())
        } else {
            Ok(manifest)
        }
    }
}

impl ConfigState for SignedUpdateManifest {
    fn max_space() -> u64 {
        256 // Enough space for a fully populated SignedUpdateManifest
    }
}