//! Instructions for the [upgradable BPF loader][ubpfl].
//!
//! [ubpfl]: crate::bpf_loader_upgradeable

#[repr(u8)]
#[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
pub enum UpgradeableLoaderInstruction {
    /// Initialize a Buffer account.
    ///
    /// A Buffer account is an intermediary that once fully populated is used
    /// with the `DeployWithMaxDataLen` instruction to populate the program's
    /// ProgramData account.
    ///
    /// The `InitializeBuffer` instruction requires no signers and MUST be
    /// included within the same Transaction as the system program's
    /// `CreateAccount` instruction that creates the account being initialized.
    /// Otherwise another party may initialize the account.
    ///
    /// # Account references
    ///   0. `[writable]` source account to initialize.
    ///   1. `[]` Buffer authority, optional, if omitted then the buffer will be
    ///      immutable.
    InitializeBuffer,

    /// Write program data into a Buffer account.
    ///
    /// # Account references
    ///   0. `[writable]` Buffer account to write program data to.
    ///   1. `[signer]` Buffer authority
    Write {
        /// Offset at which to write the given bytes.
        offset: u32,
        /// Serialized program data
        #[serde(with = "serde_bytes")]
        bytes: Vec<u8>,
    },

    /// Deploy an executable program.
    ///
    /// A program consists of a Program and ProgramData account pair.
    ///   - The Program account's address will serve as the program id for any
    ///     instructions that execute this program.
    ///   - The ProgramData account will remain mutable by the loader only and
    ///     holds the program data and authority information.  The ProgramData
    ///     account's address is derived from the Program account's address and
    ///     created by the DeployWithMaxDataLen instruction.
    ///
    /// The ProgramData address is derived from the Program account's address as
    /// follows:
    ///
    /// ```
    /// # use solana_program::pubkey::Pubkey;
    /// # use solana_program::bpf_loader_upgradeable;
    /// # let program_address = &[];
    /// let (program_data_address, _) = Pubkey::find_program_address(
    ///      &[program_address],
    ///      &bpf_loader_upgradeable::id()
    ///  );
    /// ```
    ///
    /// The `DeployWithMaxDataLen` instruction does not require the ProgramData
    /// account be a signer and therefore MUST be included within the same
    /// Transaction as the system program's `CreateAccount` instruction that
    /// creates the Program account. Otherwise another party may initialize the
    /// account.
    ///
    /// # Account references
    ///   0. `[signer]` The payer account that will pay to create the ProgramData
    ///      account.
    ///   1. `[writable]` The uninitialized ProgramData account.
    ///   2. `[writable]` The uninitialized Program account.
    ///   3. `[writable]` The Buffer account where the program data has been
    ///      written.  The buffer account's authority must match the program's
    ///      authority
    ///   4. `[]` Rent sysvar.
    ///   5. `[]` Clock sysvar.
    ///   6. `[]` System program (`solana_sdk::system_program::id()`).
    ///   7. `[signer]` The program's authority
    DeployWithMaxDataLen {
        /// Maximum length that the program can be upgraded to.
        max_data_len: usize,
    },

    /// Upgrade a program.
    ///
    /// A program can be updated as long as the program's authority has not been
    /// set to `None`.
    ///
    /// The Buffer account must contain sufficient lamports to fund the
    /// ProgramData account to be rent-exempt, any additional lamports left over
    /// will be transferred to the spill account, leaving the Buffer account
    /// balance at zero.
    ///
    /// # Account references
    ///   0. `[writable]` The ProgramData account.
    ///   1. `[writable]` The Program account.
    ///   2. `[writable]` The Buffer account where the program data has been
    ///      written.  The buffer account's authority must match the program's
    ///      authority
    ///   3. `[writable]` The spill account.
    ///   4. `[]` Rent sysvar.
    ///   5. `[]` Clock sysvar.
    ///   6. `[signer]` The program's authority.
    Upgrade,

    /// Set a new authority that is allowed to write the buffer or upgrade the
    /// program.  To permanently make the buffer immutable or disable program
    /// updates omit the new authority.
    ///
    /// # Account references
    ///   0. `[writable]` The Buffer or ProgramData account to change the
    ///      authority of.
    ///   1. `[signer]` The current authority.
    ///   2. `[]` The new authority, optional, if omitted then the program will
    ///      not be upgradeable.
    SetAuthority,

    /// Closes an account owned by the upgradeable loader of all lamports and
    /// withdraws all the lamports
    ///
    /// # Account references
    ///   0. `[writable]` The account to close, if closing a program must be the
    ///      ProgramData account.
    ///   1. `[writable]` The account to deposit the closed account's lamports.
    ///   2. `[signer]` The account's authority, Optional, required for
    ///      initialized accounts.
    ///   3. `[writable]` The associated Program account if the account to close
    ///      is a ProgramData account.
    Close,
}