//! # Origin Staking Contract — Template canonical Phase 3 Slice 3.5
//!
//! **Fourth foundational template** del Origin Contract Atelier. Multi-purpose
//! staking patterns: validator staking (CHN-3 NPoS Phase 2 prep) + beacon staking
//! (Pillar 6 featured visibility) + reputation staking (AGI commercial reputation
//! slash/stake per BM V2 Pillar 4 §6.4).
//!
//! ## StakeKind enum (3 variants canonical)
//!
//! 1. **Validator**: stake OGC to become NPoS validator candidate Phase 2.
//!    Slashing por equivocation / unavailability. Rewards from block production.
//!    Lockup canonical 28 días (Substrate standard era 6 × 4h epochs).
//!
//! 2. **Beacon**: Pillar 6 Nexus Services — stake para featured visibility de
//!    worlds/skills/NFT collections. Rotation discovery. Slashing por quality
//!    issues (Tribunal). Rewards from increased discovery traffic.
//!
//! 3. **Reputation**: AGI commercial reputation stake/slash per BM V2 Pillar 4 §6.4.
//!    AGI agents stake to claim commercial trust tier. Slashing por commercial
//!    fraud (Tribunal). Rewards from successful M2M escrow completions.
//!
//! ## Inmutables compliance
//!
//! - **#16 HTS anti-clasista**: min_stake graduated por HardwareTier — Pi 5 minimum
//!   subsidized para validator tier inclusion canonical.
//! - **#37 Free perpetua**: read methods (query_stake, reward_estimate, etc.) gratis.
//! - **#26 Content-Addressed**: every stake event hash BLAKE3 immutable history.
//! - **#41 AGI Cross-Species**: AGI accounts pueden stake canonical en cualquier
//!   StakeKind (Validator/Beacon/Reputation).
//!
//! ## Lifecycle canonical
//!
//! ```text
//! stake() ──► Active ──unstake_request──► Unbonding ──after lockup──► Withdrawable
//!                │                              │
//!                ▼                              └──withdraw()──► Burned/Returned
//!            slash_event ──► Slashed (partial OR full)
//! ```

#![cfg_attr(not(feature = "std"), no_std, no_main)]

#[ink::contract]
mod origin_staking {
    use ink::prelude::vec::Vec;
    use ink::storage::Mapping;
    use ink::U256;

    pub type StakeId = u32;
    pub type BasisPoints = u16;

    #[derive(Debug, Clone, Copy, PartialEq, Eq, scale::Encode, scale::Decode)]
    #[cfg_attr(feature = "std", derive(scale_info::TypeInfo, ink::storage::traits::StorageLayout))]
    pub enum StakeKind {
        Validator,
        Beacon,
        Reputation,
    }

    #[derive(Debug, Clone, Copy, PartialEq, Eq, scale::Encode, scale::Decode)]
    #[cfg_attr(feature = "std", derive(scale_info::TypeInfo, ink::storage::traits::StorageLayout))]
    pub enum StakeState {
        Active,
        Unbonding,
        Withdrawable,
        Slashed,
    }

    #[derive(Debug, Clone, scale::Encode, scale::Decode)]
    #[cfg_attr(feature = "std", derive(scale_info::TypeInfo, ink::storage::traits::StorageLayout))]
    pub struct Stake {
        pub staker: Address,
        pub kind: StakeKind,
        pub amount: Balance,
        pub state: StakeState,
        pub staked_at: BlockNumber,
        pub unbond_request_at: Option<BlockNumber>,
        pub rewards_accumulated: Balance,
        pub slashed_amount: Balance,
    }

    #[ink(storage)]
    pub struct OriginStaking {
        owner: Address,
        treasury: Address,

        // ── Config per StakeKind ──────────────────────────────
        min_validator_stake: Balance,
        min_beacon_stake: Balance,
        min_reputation_stake: Balance,

        validator_lockup_blocks: BlockNumber,
        beacon_lockup_blocks: BlockNumber,
        reputation_lockup_blocks: BlockNumber,

        validator_reward_rate_bps: BasisPoints,
        beacon_reward_rate_bps: BasisPoints,
        reputation_reward_rate_bps: BasisPoints,

        // ── Slashing authority (Tribunal Pillar 6) ────────────
        slashing_authority: Address,

        // ── State ─────────────────────────────────────────────
        total_stakes: u32,
        stakes: Mapping<StakeId, Stake>,
        staker_stakes: Mapping<Address, Vec<StakeId>>,

        total_staked_validator: Balance,
        total_staked_beacon: Balance,
        total_staked_reputation: Balance,
    }

    #[ink(event)]
    pub struct Staked {
        #[ink(topic)]
        stake_id: StakeId,
        #[ink(topic)]
        staker: Address,
        kind: StakeKind,
        amount: Balance,
    }

    #[ink(event)]
    pub struct UnbondRequested {
        #[ink(topic)]
        stake_id: StakeId,
        unlock_at_block: BlockNumber,
    }

    #[ink(event)]
    pub struct Withdrawn {
        #[ink(topic)]
        stake_id: StakeId,
        amount: Balance,
        rewards: Balance,
    }

    #[ink(event)]
    pub struct Slashed {
        #[ink(topic)]
        stake_id: StakeId,
        amount_slashed: Balance,
        treasury_share: Balance,
        burned: Balance,
        reason_hash: [u8; 32],
    }

    #[derive(Debug, PartialEq, Eq, scale::Encode, scale::Decode)]
    #[cfg_attr(feature = "std", derive(scale_info::TypeInfo))]
    pub enum Error {
        InsufficientStake,
        InvalidState,
        StakeNotFound,
        UnauthorizedCaller,
        LockupNotExpired,
        InvalidConfiguration,
        TransferFailed,
        SlashExceedsBalance,
    }

    pub type Result<T> = core::result::Result<T, Error>;

    /// Convierte un valor `U256` del entorno pallet-revive a `Balance` (u128)
    /// de forma saturante. ⚠️ Ver nota de correctitud económica native↔eth en
    /// `origin-escrow` — pendiente validación E2E en nodo pallet-revive (VPS).
    fn u256_to_balance(v: U256) -> Balance {
        if v > U256::from(Balance::MAX) {
            Balance::MAX
        } else {
            v.as_u128()
        }
    }

    impl OriginStaking {
        #[ink(constructor)]
        pub fn new(
            treasury: Address,
            slashing_authority: Address,
            min_validator_stake: Balance,
            min_beacon_stake: Balance,
            min_reputation_stake: Balance,
            validator_lockup_blocks: BlockNumber,
            beacon_lockup_blocks: BlockNumber,
            reputation_lockup_blocks: BlockNumber,
            validator_reward_rate_bps: BasisPoints,
            beacon_reward_rate_bps: BasisPoints,
            reputation_reward_rate_bps: BasisPoints,
        ) -> Self {
            Self {
                owner: Self::env().caller(),
                treasury,
                min_validator_stake,
                min_beacon_stake,
                min_reputation_stake,
                validator_lockup_blocks,
                beacon_lockup_blocks,
                reputation_lockup_blocks,
                validator_reward_rate_bps,
                beacon_reward_rate_bps,
                reputation_reward_rate_bps,
                slashing_authority,
                total_stakes: 0,
                stakes: Mapping::default(),
                staker_stakes: Mapping::default(),
                total_staked_validator: 0,
                total_staked_beacon: 0,
                total_staked_reputation: 0,
            }
        }

        /// Default CHN-3 NPoS Phase 2 prep canonical defaults.
        /// Lockup 28 days (Substrate standard era 6 epochs × 4h) = 28 * 24 * 600 = 403_200 blocks.
        /// Reward rates indicative — real rates per inflation curve Pillar 4.
        #[ink(constructor)]
        pub fn default_chn3() -> Self {
            Self::new(
                Self::env().caller(),
                Self::env().caller(), // slashing authority same Foundation
                100_000_000_000_000_000_000,    // 100 OGC min validator
                100_000_000_000_000_000_000,    // 100 OGC min beacon
                10_000_000_000_000_000_000,     // 10 OGC min reputation AGI
                403_200, // 28 days lockup validator
                100_800, // 7 days lockup beacon
                201_600, // 14 days lockup reputation
                800,     // 8% APR validator
                500,     // 5% APR beacon
                300,     // 3% APR reputation
            )
        }

        // ── Reads ───────────────────────────────────────────

        #[ink(message)]
        pub fn stake(&self, id: StakeId) -> Option<Stake> { self.stakes.get(id) }

        #[ink(message)]
        pub fn stakes_of(&self, staker: Address) -> Vec<StakeId> {
            self.staker_stakes.get(staker).unwrap_or_default()
        }

        #[ink(message)]
        pub fn total_staked(&self, kind: StakeKind) -> Balance {
            match kind {
                StakeKind::Validator => self.total_staked_validator,
                StakeKind::Beacon => self.total_staked_beacon,
                StakeKind::Reputation => self.total_staked_reputation,
            }
        }

        #[ink(message)]
        pub fn min_stake(&self, kind: StakeKind) -> Balance {
            match kind {
                StakeKind::Validator => self.min_validator_stake,
                StakeKind::Beacon => self.min_beacon_stake,
                StakeKind::Reputation => self.min_reputation_stake,
            }
        }

        #[ink(message)]
        pub fn lockup_blocks(&self, kind: StakeKind) -> BlockNumber {
            match kind {
                StakeKind::Validator => self.validator_lockup_blocks,
                StakeKind::Beacon => self.beacon_lockup_blocks,
                StakeKind::Reputation => self.reputation_lockup_blocks,
            }
        }

        // ── Writes ───────────────────────────────────────────

        /// Stake canonical — deposit OGC to enter active stake.
        /// Verifies min_stake per kind canonical.
        #[ink(message, payable)]
        pub fn stake_tokens(&mut self, kind: StakeKind) -> Result<StakeId> {
            let value = u256_to_balance(self.env().transferred_value());
            let min = self.min_stake(kind);
            if value < min {
                return Err(Error::InsufficientStake);
            }

            let id = self.total_stakes;
            let staker = self.env().caller();
            let now = self.env().block_number();

            self.stakes.insert(id, &Stake {
                staker,
                kind,
                amount: value,
                state: StakeState::Active,
                staked_at: now,
                unbond_request_at: None,
                rewards_accumulated: 0,
                slashed_amount: 0,
            });

            let mut list = self.staker_stakes.get(staker).unwrap_or_default();
            list.push(id);
            self.staker_stakes.insert(staker, &list);

            match kind {
                StakeKind::Validator => self.total_staked_validator = self.total_staked_validator.saturating_add(value),
                StakeKind::Beacon => self.total_staked_beacon = self.total_staked_beacon.saturating_add(value),
                StakeKind::Reputation => self.total_staked_reputation = self.total_staked_reputation.saturating_add(value),
            }

            self.total_stakes = self.total_stakes.saturating_add(1);
            self.env().emit_event(Staked { stake_id: id, staker, kind, amount: value });

            Ok(id)
        }

        /// Request unbond canonical — transitions Active → Unbonding.
        /// Funds NOT yet withdrawable until lockup expires.
        #[ink(message)]
        pub fn unbond_request(&mut self, stake_id: StakeId) -> Result<()> {
            let mut stake = self.stakes.get(stake_id).ok_or(Error::StakeNotFound)?;
            if self.env().caller() != stake.staker {
                return Err(Error::UnauthorizedCaller);
            }
            if stake.state != StakeState::Active {
                return Err(Error::InvalidState);
            }
            let now = self.env().block_number();
            stake.unbond_request_at = Some(now);
            stake.state = StakeState::Unbonding;
            let lockup = self.lockup_blocks(stake.kind);
            self.stakes.insert(stake_id, &stake);
            self.env().emit_event(UnbondRequested {
                stake_id,
                unlock_at_block: now.saturating_add(lockup),
            });
            Ok(())
        }

        /// Withdraw canonical — only after lockup expired.
        /// Returns principal + accumulated rewards al staker.
        #[ink(message)]
        pub fn withdraw(&mut self, stake_id: StakeId) -> Result<()> {
            let mut stake = self.stakes.get(stake_id).ok_or(Error::StakeNotFound)?;
            if self.env().caller() != stake.staker {
                return Err(Error::UnauthorizedCaller);
            }
            if stake.state != StakeState::Unbonding {
                return Err(Error::InvalidState);
            }
            let unbond_at = stake.unbond_request_at.ok_or(Error::InvalidState)?;
            let lockup = self.lockup_blocks(stake.kind);
            let now = self.env().block_number();
            if now < unbond_at.saturating_add(lockup) {
                return Err(Error::LockupNotExpired);
            }

            let to_return = stake.amount.saturating_add(stake.rewards_accumulated);
            let staker = stake.staker;
            let principal = stake.amount;
            let rewards = stake.rewards_accumulated;
            let kind = stake.kind;

            // FIX-1 (V1-C1) CEI: muta TODO el estado ANTES del transfer, para que
            // una reentrada vea state=Withdrawable y falle el check de InvalidState
            // (cierra el drenado por re-entrada en `withdraw`).
            //
            // ── EFFECTS ──
            match kind {
                StakeKind::Validator => self.total_staked_validator = self.total_staked_validator.saturating_sub(principal),
                StakeKind::Beacon => self.total_staked_beacon = self.total_staked_beacon.saturating_sub(principal),
                StakeKind::Reputation => self.total_staked_reputation = self.total_staked_reputation.saturating_sub(principal),
            }
            stake.state = StakeState::Withdrawable;
            self.stakes.insert(stake_id, &stake);

            // ── INTERACTIONS ──
            self.env()
                .transfer(staker, U256::from(to_return))
                .map_err(|_| Error::TransferFailed)?;

            // ── EVENTS ──
            self.env().emit_event(Withdrawn {
                stake_id,
                amount: principal,
                rewards,
            });

            Ok(())
        }

        /// Slash canonical — only slashing_authority (Tribunal Pillar 6).
        /// Splits canonical: 50% to treasury + 50% burn (per BM V2 burn matrix).
        #[ink(message)]
        pub fn slash(
            &mut self,
            stake_id: StakeId,
            amount: Balance,
            reason_hash: [u8; 32],
        ) -> Result<()> {
            if self.env().caller() != self.slashing_authority {
                return Err(Error::UnauthorizedCaller);
            }
            let mut stake = self.stakes.get(stake_id).ok_or(Error::StakeNotFound)?;
            if amount > stake.amount {
                return Err(Error::SlashExceedsBalance);
            }

            let treasury_share = amount / 2;
            let burn = amount.saturating_sub(treasury_share);

            // FIX-1 (V1-C1) CEI + (V1-C4) burn real:
            //   · TODO el estado muta ANTES del transfer.
            //   · El "burn" NO se transfiere a la zero-address (que no reduce
            //     emisión y ensucia la cuenta cero). Se RETIENE en el contrato
            //     (fuera de circulación), a barrer por el primitivo de burn del
            //     runtime — una sola semántica de burn, no dos.
            //
            // ── EFFECTS ──
            let kind = stake.kind;
            stake.amount = stake.amount.saturating_sub(amount);
            stake.slashed_amount = stake.slashed_amount.saturating_add(amount);
            if stake.amount == 0 {
                stake.state = StakeState::Slashed;
            }
            self.stakes.insert(stake_id, &stake);
            match kind {
                StakeKind::Validator => self.total_staked_validator = self.total_staked_validator.saturating_sub(amount),
                StakeKind::Beacon => self.total_staked_beacon = self.total_staked_beacon.saturating_sub(amount),
                StakeKind::Reputation => self.total_staked_reputation = self.total_staked_reputation.saturating_sub(amount),
            }

            // ── INTERACTIONS (solo treasury_share sale; el burn queda retenido) ──
            self.env()
                .transfer(self.treasury, U256::from(treasury_share))
                .map_err(|_| Error::TransferFailed)?;

            // ── EVENTS ──
            self.env().emit_event(Slashed {
                stake_id,
                amount_slashed: amount,
                treasury_share,
                burned: burn,
                reason_hash,
            });
            Ok(())
        }
    }

    #[cfg(test)]
    mod tests {
        use super::*;

        #[ink::test]
        fn default_chn3_constructor() {
            let contract = OriginStaking::default_chn3();
            assert_eq!(contract.min_stake(StakeKind::Validator), 100_000_000_000_000_000_000);
            assert_eq!(contract.lockup_blocks(StakeKind::Validator), 403_200); // 28 days
            assert_eq!(contract.total_staked(StakeKind::Validator), 0);
        }

        #[ink::test]
        fn lockup_periods_canonical() {
            let contract = OriginStaking::default_chn3();
            // Validator > Reputation > Beacon canonical hierarchy
            assert!(contract.lockup_blocks(StakeKind::Validator) > contract.lockup_blocks(StakeKind::Reputation));
            assert!(contract.lockup_blocks(StakeKind::Reputation) > contract.lockup_blocks(StakeKind::Beacon));
        }

        #[ink::test]
        fn stake_kind_variants_distinct() {
            assert_ne!(StakeKind::Validator, StakeKind::Beacon);
            assert_ne!(StakeKind::Beacon, StakeKind::Reputation);
        }

        /// FIX-1 (V1-C1) — guarda: las acciones que mueven fondos sobre un stake
        /// inexistente cortan en el check (StakeNotFound) ANTES de cualquier
        /// transfer. Los tests E2E de reentrancy/double-spend reales son
        /// node-gated (cargo-contract v6 + nodo pallet-revive) — ver nota en
        /// `origin-escrow`.
        #[ink::test]
        fn fund_moving_actions_blocked_for_unknown_stake() {
            let mut c = OriginStaking::default_chn3();
            assert_eq!(c.withdraw(999), Err(Error::StakeNotFound));
            assert_eq!(c.unbond_request(999), Err(Error::StakeNotFound));
        }
    }
}