//! Realm Account

use borsh::{BorshDeserialize, BorshSchema, BorshSerialize};
use solana_program::{
    account_info::AccountInfo, program_error::ProgramError, program_pack::IsInitialized,
    pubkey::Pubkey,
};

use crate::{
    error::GovernanceError,
    state::enums::{GovernanceAccountType, MintMaxVoteWeightSource},
    tools::account::{assert_is_valid_account, get_account_data, AccountMaxSize},
    PROGRAM_AUTHORITY_SEED,
};

/// Realm Config instruction args
#[repr(C)]
#[derive(Clone, Debug, PartialEq, BorshDeserialize, BorshSerialize, BorshSchema)]
pub struct RealmConfigArgs {
    /// Indicates whether council_mint should be used
    /// If yes then council_mint account must also be passed to the instruction
    pub use_council_mint: bool,

    /// Indicates whether custodian should be used
    /// If yes then custodian account must also be passed to the instruction  
    pub use_custodian: bool,

    /// The source used for community mint max vote weight source
    pub community_mint_max_vote_weight_source: MintMaxVoteWeightSource,
}

/// Realm Config defining Realm parameters.
#[repr(C)]
#[derive(Clone, Debug, PartialEq, BorshDeserialize, BorshSerialize, BorshSchema)]
pub struct RealmConfig {
    /// Reserved space for future versions
    pub reserved: [u8; 8],

    /// The source used for community mint max vote weight source
    pub community_mint_max_vote_weight_source: MintMaxVoteWeightSource,

    /// Optional council mint
    pub council_mint: Option<Pubkey>,

    /// An authority tasked with non-critical and maintenance Realm operations
    /// For example custodian authority is required to add governances to the Realm
    /// There is no security risk with adding governances to the Realm but it should not be open for everybody
    /// to prevent unrelated entries and noise
    /// Note: This field is not used yet. It's reserved for future versions
    pub custodian: Option<Pubkey>,
}

/// Governance Realm Account
/// Account PDA seeds" ['governance', name]
#[repr(C)]
#[derive(Clone, Debug, PartialEq, BorshDeserialize, BorshSerialize, BorshSchema)]
pub struct Realm {
    /// Governance account type
    pub account_type: GovernanceAccountType,

    /// Community mint
    pub community_mint: Pubkey,

    /// Configuration of the Realm
    pub config: RealmConfig,

    /// Reserved space for future versions
    pub reserved: [u8; 8],

    /// Realm authority. The authority must sign transactions which update the realm config
    /// The authority can be transferer to Realm Governance and hence make the Realm self governed through proposals
    pub authority: Option<Pubkey>,

    /// Governance Realm name
    pub name: String,
}

impl AccountMaxSize for Realm {
    fn get_max_size(&self) -> Option<usize> {
        Some(self.name.len() + 161)
    }
}

impl IsInitialized for Realm {
    fn is_initialized(&self) -> bool {
        self.account_type == GovernanceAccountType::Realm
    }
}

impl Realm {
    /// Asserts the given mint is either Community or Council mint of the Realm
    pub fn assert_is_valid_governing_token_mint(
        &self,
        governing_token_mint: &Pubkey,
    ) -> Result<(), ProgramError> {
        if self.community_mint == *governing_token_mint {
            return Ok(());
        }

        if self.config.council_mint == Some(*governing_token_mint) {
            return Ok(());
        }

        Err(GovernanceError::InvalidGoverningTokenMint.into())
    }

    /// Asserts the given governing token mint and holding accounts are valid for the realm
    pub fn assert_is_valid_governing_token_mint_and_holding(
        &self,
        program_id: &Pubkey,
        realm: &Pubkey,
        governing_token_mint: &Pubkey,
        governing_token_holding: &Pubkey,
    ) -> Result<(), ProgramError> {
        self.assert_is_valid_governing_token_mint(governing_token_mint)?;

        let governing_token_holding_address =
            get_governing_token_holding_address(program_id, realm, governing_token_mint);

        if governing_token_holding_address != *governing_token_holding {
            return Err(GovernanceError::InvalidGoverningTokenHoldingAccount.into());
        }

        Ok(())
    }
}

/// Checks whether realm account exists, is initialized and  owned by Governance program
pub fn assert_is_valid_realm(
    program_id: &Pubkey,
    realm_info: &AccountInfo,
) -> Result<(), ProgramError> {
    assert_is_valid_account(realm_info, GovernanceAccountType::Realm, program_id)
}

/// Deserializes account and checks owner program
pub fn get_realm_data(
    program_id: &Pubkey,
    realm_info: &AccountInfo,
) -> Result<Realm, ProgramError> {
    get_account_data::<Realm>(realm_info, program_id)
}

/// Deserializes account and checks the given authority is Realm's authority
pub fn get_realm_data_for_authority(
    program_id: &Pubkey,
    realm_info: &AccountInfo,
    realm_authority: &Pubkey,
) -> Result<Realm, ProgramError> {
    let realm_data = get_account_data::<Realm>(realm_info, program_id)?;

    if realm_data.authority.is_none() {
        return Err(GovernanceError::RealmHasNoAuthority.into());
    }

    if realm_data.authority.unwrap() != *realm_authority {
        return Err(GovernanceError::InvalidAuthorityForRealm.into());
    }

    Ok(realm_data)
}

/// Deserializes Ream account and asserts the given governing_token_mint is either Community or Council mint of the Realm
pub fn get_realm_data_for_governing_token_mint(
    program_id: &Pubkey,
    realm_info: &AccountInfo,
    governing_token_mint: &Pubkey,
) -> Result<Realm, ProgramError> {
    let realm_data = get_realm_data(program_id, realm_info)?;

    realm_data.assert_is_valid_governing_token_mint(governing_token_mint)?;

    Ok(realm_data)
}

/// Returns Realm PDA seeds
pub fn get_realm_address_seeds(name: &str) -> [&[u8]; 2] {
    [PROGRAM_AUTHORITY_SEED, name.as_bytes()]
}

/// Returns Realm PDA address
pub fn get_realm_address(program_id: &Pubkey, name: &str) -> Pubkey {
    Pubkey::find_program_address(&get_realm_address_seeds(name), program_id).0
}

/// Returns Realm Token Holding PDA seeds
pub fn get_governing_token_holding_address_seeds<'a>(
    realm: &'a Pubkey,
    governing_token_mint: &'a Pubkey,
) -> [&'a [u8]; 3] {
    [
        PROGRAM_AUTHORITY_SEED,
        realm.as_ref(),
        governing_token_mint.as_ref(),
    ]
}

/// Returns Realm Token Holding PDA address
pub fn get_governing_token_holding_address(
    program_id: &Pubkey,
    realm: &Pubkey,
    governing_token_mint: &Pubkey,
) -> Pubkey {
    Pubkey::find_program_address(
        &get_governing_token_holding_address_seeds(realm, governing_token_mint),
        program_id,
    )
    .0
}

/// Asserts given realm config args are correct
pub fn assert_valid_realm_config_args(config_args: &RealmConfigArgs) -> Result<(), ProgramError> {
    match config_args.community_mint_max_vote_weight_source {
        MintMaxVoteWeightSource::SupplyFraction(fraction) => {
            if !(1..=MintMaxVoteWeightSource::SUPPLY_FRACTION_BASE).contains(&fraction) {
                return Err(GovernanceError::InvalidMaxVoteWeightSupplyFraction.into());
            }
        }
        _ => return Err(GovernanceError::MintMaxVoteWeightSourceNotSupported.into()),
    }

    Ok(())
}

#[cfg(test)]
mod test {

    use super::*;

    #[test]
    fn test_max_size() {
        let realm = Realm {
            account_type: GovernanceAccountType::Realm,
            community_mint: Pubkey::new_unique(),
            reserved: [0; 8],

            authority: Some(Pubkey::new_unique()),
            name: "test-realm".to_string(),
            config: RealmConfig {
                council_mint: Some(Pubkey::new_unique()),
                reserved: [0; 8],
                custodian: Some(Pubkey::new_unique()),
                community_mint_max_vote_weight_source: MintMaxVoteWeightSource::Absolute(100),
            },
        };

        let size = realm.try_to_vec().unwrap().len();

        assert_eq!(realm.get_max_size(), Some(size));
    }
}