#![allow(clippy::string_lit_as_bytes)]
#![allow(clippy::redundant_closure_call)]
#![allow(clippy::type_complexity)]
#![cfg_attr(not(feature = "std"), no_std)]
//! This court module is for dispute resolution
//! - stores vote metadata to schedule and dispatch votes to resolve disputes

#[cfg(test)]
mod tests;

use codec::Codec;
use frame_support::{
    decl_error,
    decl_event,
    decl_module,
    decl_storage,
    ensure,
    traits::{
        Currency,
        ExistenceRequirement,
        Get,
        ReservableCurrency,
    },
    Parameter,
};
use frame_system::{
    self as system,
    ensure_signed,
};
use sp_runtime::{
    traits::{
        AtLeast32Bit,
        MaybeSerializeDeserialize,
        Member,
        Zero,
    },
    DispatchError,
    DispatchResult,
};
use sp_std::{
    fmt::Debug,
    prelude::*,
};
use util::{
    court::{
        Dispute,
        DisputeState,
        ResolutionMetadata,
    },
    traits::{
        GenerateUniqueID,
        GetVoteOutcome,
        IDIsAvailable,
        OpenVote,
        RegisterDisputeType,
    },
    vote::VoteOutcome,
};

/// The balances type for this module
type BalanceOf<T> = <<T as Trait>::Currency as Currency<
    <T as frame_system::Trait>::AccountId,
>>::Balance;
/// The vote identifier for the vote module
type VoteId<T> = <T as vote::Trait>::VoteId;
/// The signal type for the vote module
type Signal<T> = <T as vote::Trait>::Signal;

pub trait Trait: frame_system::Trait + org::Trait + vote::Trait {
    /// The overarching event type
    type Event: From<Event<Self>> + Into<<Self as frame_system::Trait>::Event>;

    /// The currency type
    /// - TODO: consider switching Reservable for Lockable?
    type Currency: Currency<Self::AccountId>
        + ReservableCurrency<Self::AccountId>;

    /// The identifier for disputes
    type DisputeId: Parameter
        + Member
        + AtLeast32Bit
        + Codec
        + Default
        + Copy
        + MaybeSerializeDeserialize
        + Debug
        + PartialOrd
        + PartialEq
        + Zero;

    /// The minimum amount for any dispute registered in this module
    type MinimumDisputeAmount: Get<BalanceOf<Self>>;
}

decl_event!(
    pub enum Event<T>
    where
        <T as frame_system::Trait>::AccountId,
        <T as org::Trait>::OrgId,
        <T as vote::Trait>::VoteId,
        <T as Trait>::DisputeId,
        Balance = BalanceOf<T>,

    {
        RegisteredDisputeWithResolutionPath(DisputeId, AccountId, Balance, AccountId, OrgId),
        DisputeRaisedAndVoteTriggered(DisputeId, AccountId, Balance, AccountId, OrgId, VoteId),
        DisputeAcceptedAndLockedFundsTransferred(DisputeId, AccountId, Balance, AccountId, OrgId, VoteId),
        DisputeRejectedAndLockedFundsUnlocked(DisputeId, AccountId, Balance, AccountId, OrgId, VoteId),
    }
);

decl_error! {
    pub enum Error for Module<T: Trait> {
        /// Must register dispute with resolution path before raising one
        CannotRaiseDisputeIfDisputeStateDNE,
        DisputeMustExceedModuleMinimum,
        CannotPollDisputeIfDisputeStateDNE,
        SignerNotAuthorizedToRaiseThisDispute,
        ActiveDisputeCannotBeRaisedFromCurrentState,
        ActiveDisputeCannotBePolledFromCurrentState,
        VoteOutcomeInconclusiveSoPollCannotExecuteOutcome,
    }
}

decl_storage! {
    trait Store for Module<T: Trait> as Court {
        /// The nonce for unique dispute id generation
        DisputeIdCounter get(fn dispute_id_counter): T::DisputeId;

        /// The number of open disputes
        pub OpenDisputeCounter get(fn open_dispute_counter): u32;

        /// The state of disputes
        pub DisputeStates get(fn dispute_states): map
            hasher(blake2_128_concat) T::DisputeId => Option<
                    Dispute<
                        T::AccountId,
                        BalanceOf<T>,
                        T::BlockNumber,
                        ResolutionMetadata<
                            T::OrgId,
                            Signal<T>,
                            T::BlockNumber
                        >,
                        DisputeState<VoteId<T>>,
                    >
                >;
    }
}

decl_module! {
    pub struct Module<T: Trait> for enum Call where origin: T::Origin {
        type Error = Error<T>;
        fn deposit_event() = default;

        #[weight = 0]
        fn register_dispute_type_with_resolution_path(
            origin,
            amount_to_lock: BalanceOf<T>,
            dispute_raiser: T::AccountId,
            resolution_metadata: ResolutionMetadata<T::OrgId, Signal<T>, T::BlockNumber>,
            expiry: Option<T::BlockNumber>,
        ) -> DispatchResult {
            let locker = ensure_signed(origin)?;
            // get court org before new dispute state consumes resolution metadata
            let court_org = resolution_metadata.org();
            let new_dispute_id = Self::register_dispute_type(
                locker.clone(),
                amount_to_lock,
                dispute_raiser.clone(),
                resolution_metadata,
                expiry,
            )?;
            // emit the event with the DisputeId
            Self::deposit_event(RawEvent::RegisteredDisputeWithResolutionPath(new_dispute_id, locker, amount_to_lock, dispute_raiser, court_org));
            Ok(())
        }
        #[weight = 0]
        fn raise_dispute_to_trigger_vote(
            origin,
            dispute_id: T::DisputeId,
        ) -> DispatchResult {
            let trigger = ensure_signed(origin)?;
            let dispute = <DisputeStates<T>>::get(dispute_id).ok_or(Error::<T>::CannotRaiseDisputeIfDisputeStateDNE)?;
            // ensure that the signer can trigger this dispute
            ensure!(dispute.can_raise_dispute(&trigger), Error::<T>::SignerNotAuthorizedToRaiseThisDispute);
            // check that it is in a valid state to trigger the dispute
            let (new_dispute, dispatched_vote_id) = match dispute.state() {
                DisputeState::DisputeNotRaised => {
                    let resolution_metadata = dispute.resolution_metadata();
                    // use the resolution metadata to trigger the vote
                    let new_vote_id = <vote::Module<T>>::open_vote(None, resolution_metadata.org(), resolution_metadata.passage_threshold(), resolution_metadata.rejection_threshold(), resolution_metadata.duration())?;
                    // update the state of the dispute with the new vote identifier
                    let updated_dispute = dispute.set_state(DisputeState::DisputeRaisedAndVoteDispatched(new_vote_id));
                    // return tuple
                    (updated_dispute, new_vote_id)
                },
                // throw error if not in a state to trigger vote
                _ => return Err(Error::<T>::ActiveDisputeCannotBeRaisedFromCurrentState.into()),
            };
            let (locker, amt_locked, court_org) = (
                new_dispute.locker(),
                new_dispute.locked_funds(),
                new_dispute.resolution_metadata().org(),
            );
            // insert new dispute state
            <DisputeStates<T>>::insert(dispute_id, new_dispute);
            // emit the event with the VoteId
            Self::deposit_event(RawEvent::DisputeRaisedAndVoteTriggered(dispute_id, locker, amt_locked, trigger, court_org, dispatched_vote_id));
            Ok(())
        }
        #[weight = 0]
        fn poll_dispute_to_execute_outcome(
            origin,
            dispute_id: T::DisputeId,
        ) -> DispatchResult {
            let _ = ensure_signed(origin)?;
            let dispute = <DisputeStates<T>>::get(dispute_id).ok_or(Error::<T>::CannotPollDisputeIfDisputeStateDNE)?;
            // _could_ verify poller in context of dispute here

            // match on the dispute's current state
            let new_dispute_state = match dispute.state() {
                DisputeState::DisputeRaisedAndVoteDispatched(live_vote_id) => {
                    // check the vote outcome
                    let outcome = <vote::Module<T>>::get_vote_outcome(live_vote_id)?;
                    match outcome {
                        VoteOutcome::Approved => {
                            // unreserve capital from locker
                            let _ = T::Currency::unreserve(&dispute.locker(), dispute.locked_funds());
                            // transfer from locker to dispute_raiser
                            T::Currency::transfer(&dispute.locker(), &dispute.dispute_raiser(), dispute.locked_funds(), ExistenceRequirement::KeepAlive)?;
                            // update dispute state
                            dispute.set_state(DisputeState::DisputeRaisedAndAccepted(live_vote_id))
                        }
                        VoteOutcome::Rejected => {
                            // unreserve capital from locker
                            let _ = T::Currency::unreserve(&dispute.locker(), dispute.locked_funds());
                            // update dispute state
                            dispute.set_state(DisputeState::DisputeRaisedAndRejected(live_vote_id))
                        }
                        _ => return Err(Error::<T>::VoteOutcomeInconclusiveSoPollCannotExecuteOutcome.into()),
                    }
                }
                _ => return Err(Error::<T>::ActiveDisputeCannotBePolledFromCurrentState.into()),
            };
            // insert new dispute state
            <DisputeStates<T>>::insert(dispute_id, new_dispute_state);
            // emit the event with the outcome
            Ok(())
        }
    }
}

impl<T: Trait> IDIsAvailable<T::DisputeId> for Module<T> {
    fn id_is_available(id: T::DisputeId) -> bool {
        <DisputeStates<T>>::get(id).is_none()
    }
}

impl<T: Trait> GenerateUniqueID<T::DisputeId> for Module<T> {
    fn generate_unique_id() -> T::DisputeId {
        let mut id_counter = <DisputeIdCounter<T>>::get() + 1u32.into();
        while <DisputeStates<T>>::get(id_counter).is_some() {
            id_counter += 1u32.into();
        }
        <DisputeIdCounter<T>>::put(id_counter);
        id_counter
    }
}

impl<T: Trait>
    RegisterDisputeType<
        T::AccountId,
        BalanceOf<T>,
        ResolutionMetadata<T::OrgId, Signal<T>, T::BlockNumber>,
        T::BlockNumber,
    > for Module<T>
{
    type DisputeIdentifier = T::DisputeId;
    fn register_dispute_type(
        locker: T::AccountId,
        amount_to_lock: BalanceOf<T>,
        dispute_raiser: T::AccountId,
        resolution_path: ResolutionMetadata<
            T::OrgId,
            Signal<T>,
            T::BlockNumber,
        >,
        expiry: Option<T::BlockNumber>,
    ) -> Result<Self::DisputeIdentifier, DispatchError> {
        ensure!(
            amount_to_lock >= T::MinimumDisputeAmount::get(),
            Error::<T>::DisputeMustExceedModuleMinimum
        );
        // lock the amount in question
        T::Currency::reserve(&locker, amount_to_lock)?;
        // form the dispute state
        let new_dispute_state = Dispute::new(
            locker,
            amount_to_lock,
            dispute_raiser,
            resolution_path,
            DisputeState::DisputeNotRaised,
            expiry,
        );
        // generate unique dispute identifier
        let new_dispute_id = Self::generate_unique_id();
        // insert the dispute state
        <DisputeStates<T>>::insert(new_dispute_id, new_dispute_state);
        Ok(new_dispute_id)
    }
}