use crate::error::AnyResult;
use crate::AddressGenerator;
use cosmwasm_std::{instantiate2_address, Addr, Api, CanonicalAddr, Storage};
use sha2::digest::Update;
use sha2::{Digest, Sha256};

/// Address generator that mimics the original `wasmd` behavior.
///
/// [MockAddressGenerator] implements [AddressGenerator] trait in terms of
/// [`contract_address`](AddressGenerator::contract_address) and
/// [`predictable_contract_address`](AddressGenerator::predictable_contract_address) functions:
/// - `contract_address` generates non-predictable addresses for contracts,
///   using the same algorithm as `wasmd`, see: [`BuildContractAddressClassic`] for details.
/// - `predictable_contract_address` generates predictable addresses for contracts using
///   [`instantiate2_address`] function defined in `cosmwasm-std`.
///
/// [`BuildContractAddressClassic`]:https://github.com/CosmWasm/wasmd/blob/3b6512c9f154995188ead84ab3bd9e034b49a0f3/x/wasm/keeper/addresses.go#L35-L41
/// [`instantiate2_address`]:https://github.com/CosmWasm/cosmwasm/blob/8a652d7cd8071f71139deca6be8194ed4a278b2c/packages/std/src/addresses.rs#L309-L318
#[derive(Default)]
pub struct MockAddressGenerator;

impl AddressGenerator for MockAddressGenerator {
    /// Generates a _non-predictable_ contract address, like `wasmd` does it in real-life chain.
    ///
    /// Note that addresses generated by `wasmd` may change and users **should not**
    /// rely on this value in any extend.
    ///
    /// Returns the contract address after its instantiation.
    /// Address generated by this function is returned as a result
    /// of processing `WasmMsg::Instantiate` message.
    ///
    /// **NOTES**
    /// > 👉 The canonical address generated by this function is humanized using the
    /// > `Api::addr_humanize` function, so the resulting value depends on used `Api` implementation.
    /// > The following example uses Bech32 format for humanizing canonical addresses.
    ///
    /// > 👉 Do NOT use this function **directly** to generate a contract address,
    /// > pass this address generator to `WasmKeeper`:
    /// > `WasmKeeper::new().with_address_generator(MockAddressGenerator::default());`
    ///
    /// # Example
    ///
    /// ```
    /// # use cosmwasm_std::testing::MockStorage;
    /// # use cw_multi_test::AddressGenerator;
    /// # use cw_multi_test::addons::{MockAddressGenerator, MockApiBech32};
    /// // use `Api` that implements Bech32 format
    /// let api = MockApiBech32::new("juno");
    /// // prepare mock storage
    /// let mut storage = MockStorage::default();
    /// // initialize the address generator
    /// let address_generator = MockAddressGenerator::default();
    /// // generate the address
    /// let addr = address_generator.contract_address(&api, &mut storage, 1, 1).unwrap();
    ///
    /// assert_eq!(addr.to_string(),
    ///            "juno14hj2tavq8fpesdwxxcu44rty3hh90vhujrvcmstl4zr3txmfvw9skjuwg8");
    /// ```
    fn contract_address(
        &self,
        api: &dyn Api,
        _storage: &mut dyn Storage,
        code_id: u64,
        instance_id: u64,
    ) -> AnyResult<Addr> {
        let canonical_addr = instantiate_address(code_id, instance_id);
        Ok(Addr::unchecked(api.addr_humanize(&canonical_addr)?))
    }

    /// Generates a _predictable_ contract address, like `wasmd` does it in real-life chain.
    ///
    /// Returns a contract address after its instantiation.
    /// Address generated by this function is returned as a result
    /// of processing `WasmMsg::Instantiate2` message.
    ///
    /// **NOTES**
    /// > 👉 The canonical address generated by this function is humanized using the
    /// > `Api::addr_humanize` function, so the resulting value depends on used `Api` implementation.
    /// > The following example uses Bech32 format for humanizing canonical addresses.
    ///
    /// > 👉 Do NOT use this function **directly** to generate a contract address,
    /// > pass this address generator to WasmKeeper:
    /// > `WasmKeeper::new().with_address_generator(MockAddressGenerator::default());`
    ///
    /// # Example
    ///
    /// ```
    /// # use cosmwasm_std::Api;
    /// # use cosmwasm_std::testing::MockStorage;
    /// # use cw_multi_test::AddressGenerator;
    /// # use cw_multi_test::addons::{MockAddressGenerator, MockApiBech32};
    /// // use `Api` that implements Bech32 format
    /// let api = MockApiBech32::new("juno");
    /// // prepare mock storage
    /// let mut storage = MockStorage::default();
    /// // initialize the address generator
    /// let address_generator = MockAddressGenerator::default();
    /// // checksum of the contract code base
    /// let checksum = [0, 1 ,2 ,3 ,4 ,5 ,6 ,7 ,8 ,9 ,10,
    ///                 11,12,13,14,15,16,17,18,19,20,21,
    ///                 22,23,24,25,26,27,28,29,30,31];
    /// // creator address
    /// let creator = api.addr_canonicalize(api.addr_make("creator").as_str()).unwrap();
    /// // salt
    /// let salt = [10,11,12];
    /// // generate the address
    /// let addr = address_generator
    ///     .predictable_contract_address(&api, &mut storage, 1, 1, &checksum, &creator, &salt)
    ///     .unwrap();
    ///
    /// assert_eq!(addr.to_string(),
    ///            "juno1sv3gjp85m3xxluxreruards8ruxk5ykys8qfljwrdj5tv8kqxuhsmlfyud");
    /// ```
    fn predictable_contract_address(
        &self,
        api: &dyn Api,
        _storage: &mut dyn Storage,
        _code_id: u64,
        _instance_id: u64,
        checksum: &[u8],

        creator: &CanonicalAddr,
        salt: &[u8],
    ) -> AnyResult<Addr> {
        let canonical_addr = instantiate2_address(checksum, creator, salt)?;
        Ok(Addr::unchecked(api.addr_humanize(&canonical_addr)?))
    }
}

/// Returns non-predictable contract address.
///
/// Address is generated using the same algorithm as [`BuildContractAddressClassic`]
/// implementation in `wasmd`.
///
/// [`BuildContractAddressClassic`]:https://github.com/CosmWasm/wasmd/blob/3b6512c9f154995188ead84ab3bd9e034b49a0f3/x/wasm/keeper/addresses.go#L35-L41
fn instantiate_address(code_id: u64, instance_id: u64) -> CanonicalAddr {
    let mut key = Vec::<u8>::new();
    key.extend_from_slice(b"wasm\0");
    key.extend_from_slice(&code_id.to_be_bytes());
    key.extend_from_slice(&instance_id.to_be_bytes());
    let module = Sha256::digest("module".as_bytes());
    Sha256::new()
        .chain(module)
        .chain(key)
        .finalize()
        .to_vec()
        .into()
}