//! acc_redemption - NAC 原生协议实现
//! 从 acc_remaining_protocols.rs 提取
use crate::primitives::{Address, Hash, Timestamp};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub enum ACCRedemptionError {
    RedemptionNotFound(Hash),
    InsufficientRedemptionFund { available: u128, requested: u128 },
    RedemptionWindowClosed,
    InvalidConstitutionalReceipt,
    Unauthorized(Address),
    RedemptionAlreadyProcessed(Hash),
}
impl std::fmt::Display for ACCRedemptionError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::RedemptionNotFound(h) => write!(f, "赎回请求不存在: {}", h.to_hex()),
            Self::InsufficientRedemptionFund { available, requested } => write!(f, "赎回资金不足: 可用 {}，请求 {}", available, requested),
            Self::RedemptionWindowClosed => write!(f, "赎回窗口已关闭"),
            Self::InvalidConstitutionalReceipt => write!(f, "宪法收据无效"),
            Self::Unauthorized(a) => write!(f, "未授权: {}", a.to_hex()),
            Self::RedemptionAlreadyProcessed(h) => write!(f, "赎回请求已处理: {}", h.to_hex()),
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum RedemptionStatus { Pending, Processing, Completed, Rejected, Cancelled }

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RedemptionRequest {
    pub redemption_id: Hash,
    pub asset_id: Hash,
    pub redeemer: Address,
    pub amount: u128,
    pub redemption_price_xtzh: u128,
    pub total_redemption_xtzh: u128,
    pub status: RedemptionStatus,
    pub requested_at: Timestamp,
    pub processed_at: Option<Timestamp>,
    pub constitutional_receipt: Hash,
    pub rejection_reason: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum RedemptionProtocolEvent {
    RedemptionRequested { redemption_id: Hash, asset_id: Hash, redeemer: Address, amount: u128, timestamp: Timestamp },
    RedemptionCompleted { redemption_id: Hash, total_xtzh: u128, timestamp: Timestamp },
    RedemptionRejected { redemption_id: Hash, reason: String, timestamp: Timestamp },
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ACCRedemptionProtocol {
    pub protocol_uid: String,
    pub lens_protocol_vector: String,
    pub requests: HashMap<Hash, RedemptionRequest>,
    pub redemption_fund: HashMap<Hash, u128>,
    pub redemption_window_open: bool,
    pub pending_events: Vec<RedemptionProtocolEvent>,
    pub created_at: Timestamp,
    pub updated_at: Timestamp,
}
impl ACCRedemptionProtocol {
    pub fn new() -> Self {
        Self {
            protocol_uid: "nac.acc.ACCRedemptionProtocol.v1".to_string(),
            lens_protocol_vector: "ACC-Redemption".to_string(),
            requests: HashMap::new(), redemption_fund: HashMap::new(),
            redemption_window_open: true, pending_events: Vec::new(),
            created_at: Timestamp::now(), updated_at: Timestamp::now(),
        }
    }
    pub fn fund_redemption_pool(&mut self, asset_id: Hash, amount_xtzh: u128, constitutional_receipt: Hash) -> Result<(), ACCRedemptionError> {
        if constitutional_receipt.is_zero() { return Err(ACCRedemptionError::InvalidConstitutionalReceipt); }
        *self.redemption_fund.entry(asset_id).or_insert(0) += amount_xtzh;
        Ok(())
    }
    pub fn request_redemption(
        &mut self, asset_id: Hash, redeemer: Address, amount: u128,
        redemption_price_xtzh: u128, constitutional_receipt: Hash, timestamp: Timestamp,
    ) -> Result<Hash, ACCRedemptionError> {
        if !self.redemption_window_open { return Err(ACCRedemptionError::RedemptionWindowClosed); }
        let total = amount.saturating_mul(redemption_price_xtzh);
        let available = self.redemption_fund.get(&asset_id).copied().unwrap_or(0);
        if available < total { return Err(ACCRedemptionError::InsufficientRedemptionFund { available, requested: total }); }
        let mut data = Vec::new();
        data.extend_from_slice(asset_id.as_bytes());
        data.extend_from_slice(redeemer.as_bytes());
        data.extend_from_slice(&timestamp.as_secs().to_be_bytes());
        let redemption_id = Hash::sha3_384(&data);
        let request = RedemptionRequest {
            redemption_id, asset_id, redeemer: redeemer.clone(), amount,
            redemption_price_xtzh, total_redemption_xtzh: total,
            status: RedemptionStatus::Pending,
            requested_at: timestamp.clone(), processed_at: None,
            constitutional_receipt, rejection_reason: None,
        };
        self.requests.insert(redemption_id, request);
        self.pending_events.push(RedemptionProtocolEvent::RedemptionRequested { redemption_id, asset_id, redeemer, amount, timestamp });
        self.updated_at = Timestamp::now();
        Ok(redemption_id)
    }
    pub fn complete_redemption(&mut self, redemption_id: Hash, constitutional_receipt: Hash, timestamp: Timestamp) -> Result<u128, ACCRedemptionError> {
        if constitutional_receipt.is_zero() { return Err(ACCRedemptionError::InvalidConstitutionalReceipt); }
        let request = self.requests.get_mut(&redemption_id).ok_or(ACCRedemptionError::RedemptionNotFound(redemption_id))?;
        if request.status != RedemptionStatus::Pending { return Err(ACCRedemptionError::RedemptionAlreadyProcessed(redemption_id)); }
        let total = request.total_redemption_xtzh;
        let asset_id = request.asset_id;
        if let Some(fund) = self.redemption_fund.get_mut(&asset_id) { *fund = fund.saturating_sub(total); }
        request.status = RedemptionStatus::Completed;
        request.processed_at = Some(timestamp.clone());
        self.pending_events.push(RedemptionProtocolEvent::RedemptionCompleted { redemption_id, total_xtzh: total, timestamp });
        Ok(total)
    }
    pub fn get_request(&self, id: &Hash) -> Option<&RedemptionRequest> { self.requests.get(id) }
    pub fn drain_pending_events(&mut self) -> Vec<RedemptionProtocolEvent> { std::mem::take(&mut self.pending_events) }
}

impl ACCRedemptionProtocol {
    /// 取消赎回申请
    pub fn cancel_redemption(
        &mut self,
        redemption_id: &Hash,
        requester: &Address,
        constitutional_receipt: Hash,
        timestamp: Timestamp,
    ) -> Result<(), ACCRedemptionError> {
        if constitutional_receipt.is_zero() {
            return Err(ACCRedemptionError::InvalidConstitutionalReceipt);
        }
        let req = self.requests.get_mut(redemption_id)
            .ok_or(ACCRedemptionError::RedemptionNotFound(redemption_id.clone()))?;
        if &req.redeemer != requester {
            return Err(ACCRedemptionError::Unauthorized(requester.clone()));
        }
        req.status = RedemptionStatus::Cancelled;
        req.processed_at = Some(timestamp);
        Ok(())
    }

    /// 获取待处理申请列表
    pub fn get_pending_requests(&self) -> Vec<&RedemptionRequest> {
        self.requests.values()
            .filter(|r| r.status == RedemptionStatus::Pending)
            .collect()
    }

    /// 获取赎回池余额
    pub fn get_pool_balance(&self, asset_id: &Hash) -> u128 {
        self.redemption_fund.get(asset_id).copied().unwrap_or(0)
    }

    /// 获取所有申请（按资产）
    pub fn get_requests_by_asset(&self, asset_id: &Hash) -> Vec<&RedemptionRequest> {
        self.requests.values()
            .filter(|r| &r.asset_id == asset_id)
            .collect()
    }

    /// 获取申请总数
    pub fn total_requests(&self) -> usize {
        self.requests.len()
    }
}