//! CBP节点退出机制
//! 
//! 实现CBP节点的退出申请、审核、确认和记录功能

use crate::{CbpNode, CbpStatus, CbppL1Error};
use nac_udm::primitives::Address;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// 退出状态
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum ExitStatus {
    /// 待审核
    Pending,
    /// 审核通过
    Approved,
    /// 审核拒绝
    Rejected,
    /// 已确认
    Confirmed,
    /// 已取消
    Cancelled,
}

/// 退出原因
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum ExitReason {
    /// 主动退出
    Voluntary,
    /// 硬件故障
    HardwareFailure,
    /// 违规被迫退出
    Violation,
    /// 质押不足
    InsufficientStake,
    /// 其他原因
    Other(String),
}

/// 退出申请
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExitRequest {
    /// CBP地址
    pub address: Address,
    /// 退出原因
    pub reason: ExitReason,
    /// 申请时间
    pub requested_at: u64,
    /// 退出状态
    pub status: ExitStatus,
    /// 审核时间
    pub reviewed_at: Option<u64>,
    /// 审核人
    pub reviewer: Option<Address>,
    /// 审核意见
    pub review_comment: Option<String>,
    /// 确认时间
    pub confirmed_at: Option<u64>,
}

impl ExitRequest {
    pub fn new(address: Address, reason: ExitReason, timestamp: u64) -> Self {
        Self {
            address,
            reason,
            requested_at: timestamp,
            status: ExitStatus::Pending,
            reviewed_at: None,
            reviewer: None,
            review_comment: None,
            confirmed_at: None,
        }
    }
}

/// 退出记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExitRecord {
    /// CBP地址
    pub address: Address,
    /// 退出原因
    pub reason: ExitReason,
    /// 申请时间
    pub requested_at: u64,
    /// 确认时间
    pub confirmed_at: u64,
    /// 质押金额
    pub stake_amount: u64,
    /// 赎回金额
    pub redemption_amount: u64,
    /// 处罚金额
    pub penalty_amount: u64,
    /// 声誉分数
    pub final_reputation: f64,
    /// 生产区块数
    pub blocks_produced: u64,
}

/// 退出管理器
pub struct ExitManager {
    /// 退出申请
    requests: HashMap<Address, ExitRequest>,
    /// 退出记录
    records: Vec<ExitRecord>,
    /// 审核等待期（秒）
    review_period: u64,
    /// 确认等待期（秒）
    confirmation_period: u64,
}

impl ExitManager {
    pub fn new() -> Self {
        Self {
            requests: HashMap::new(),
            records: Vec::new(),
            review_period: 7 * 24 * 3600, // 7天
            confirmation_period: 14 * 24 * 3600, // 14天
        }
    }

    /// 提交退出申请
    pub fn submit_exit_request(
        &mut self,
        node: &CbpNode,
        reason: ExitReason,
        timestamp: u64,
    ) -> Result<(), CbppL1Error> {
        // 检查节点状态
        if node.status == CbpStatus::Exited {
            return Err(CbppL1Error::InvalidStatus("Node already exited".to_string()));
        }

        // 检查是否已有待处理的申请
        if let Some(existing) = self.requests.get(&node.address) {
            if existing.status == ExitStatus::Pending || existing.status == ExitStatus::Approved {
                return Err(CbppL1Error::ExitRequestExists);
            }
        }

        // 创建退出申请
        let request = ExitRequest::new(node.address, reason, timestamp);
        self.requests.insert(node.address, request);

        Ok(())
    }

    /// 审核退出申请
    pub fn review_exit_request(
        &mut self,
        address: &Address,
        approved: bool,
        reviewer: Address,
        comment: Option<String>,
        timestamp: u64,
    ) -> Result<(), CbppL1Error> {
        let request = self.requests.get_mut(address)
            .ok_or(CbppL1Error::ExitRequestNotFound)?;

        // 检查申请状态
        if request.status != ExitStatus::Pending {
            return Err(CbppL1Error::InvalidStatus(
                format!("Request status is {:?}, expected Pending", request.status)
            ));
        }

        // 检查审核等待期
        if timestamp < request.requested_at + self.review_period {
            return Err(CbppL1Error::ReviewPeriodNotMet);
        }

        // 更新申请状态
        request.status = if approved {
            ExitStatus::Approved
        } else {
            ExitStatus::Rejected
        };
        request.reviewed_at = Some(timestamp);
        request.reviewer = Some(reviewer);
        request.review_comment = comment;

        Ok(())
    }

    /// 确认退出
    pub fn confirm_exit(
        &mut self,
        address: &Address,
        node: &CbpNode,
        redemption_amount: u64,
        penalty_amount: u64,
        timestamp: u64,
    ) -> Result<(), CbppL1Error> {
        let request = self.requests.get_mut(address)
            .ok_or(CbppL1Error::ExitRequestNotFound)?;

        // 检查申请状态
        if request.status != ExitStatus::Approved {
            return Err(CbppL1Error::InvalidStatus(
                format!("Request status is {:?}, expected Approved", request.status)
            ));
        }

        // 检查确认等待期
        let reviewed_at = request.reviewed_at.ok_or(CbppL1Error::InvalidStatus(
            "Request not reviewed".to_string()
        ))?;
        if timestamp < reviewed_at + self.confirmation_period {
            return Err(CbppL1Error::ConfirmationPeriodNotMet);
        }

        // 更新申请状态
        request.status = ExitStatus::Confirmed;
        request.confirmed_at = Some(timestamp);

        // 创建退出记录
        let record = ExitRecord {
            address: *address,
            reason: request.reason.clone(),
            requested_at: request.requested_at,
            confirmed_at: timestamp,
            stake_amount: node.stake_amount,
            redemption_amount,
            penalty_amount,
            final_reputation: node.reputation,
            blocks_produced: node.blocks_produced,
        };
        self.records.push(record);

        Ok(())
    }

    /// 取消退出申请
    pub fn cancel_exit_request(&mut self, address: &Address) -> Result<(), CbppL1Error> {
        let request = self.requests.get_mut(address)
            .ok_or(CbppL1Error::ExitRequestNotFound)?;

        // 只能取消待审核的申请
        if request.status != ExitStatus::Pending {
            return Err(CbppL1Error::InvalidStatus(
                format!("Cannot cancel request with status {:?}", request.status)
            ));
        }

        request.status = ExitStatus::Cancelled;
        Ok(())
    }

    /// 获取退出申请
    pub fn get_exit_request(&self, address: &Address) -> Option<&ExitRequest> {
        self.requests.get(address)
    }

    /// 获取所有待审核的申请
    pub fn get_pending_requests(&self) -> Vec<&ExitRequest> {
        self.requests.values()
            .filter(|r| r.status == ExitStatus::Pending)
            .collect()
    }

    /// 获取退出记录
    pub fn get_exit_records(&self, address: Option<&Address>) -> Vec<&ExitRecord> {
        if let Some(addr) = address {
            self.records.iter()
                .filter(|r| &r.address == addr)
                .collect()
        } else {
            self.records.iter().collect()
        }
    }

    /// 获取退出统计
    pub fn get_exit_statistics(&self) -> ExitStatistics {
        let total_exits = self.records.len();
        let voluntary_exits = self.records.iter()
            .filter(|r| r.reason == ExitReason::Voluntary)
            .count();
        let violation_exits = self.records.iter()
            .filter(|r| r.reason == ExitReason::Violation)
            .count();
        let total_penalties = self.records.iter()
            .map(|r| r.penalty_amount)
            .sum();

        ExitStatistics {
            total_exits,
            voluntary_exits,
            violation_exits,
            total_penalties,
        }
    }
}

impl Default for ExitManager {
    fn default() -> Self {
        Self::new()
    }
}

/// 退出统计
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExitStatistics {
    /// 总退出数
    pub total_exits: usize,
    /// 主动退出数
    pub voluntary_exits: usize,
    /// 违规退出数
    pub violation_exits: usize,
    /// 总处罚金额
    pub total_penalties: u64,
}

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

    fn create_test_node() -> CbpNode {
        CbpNode {
            address: Address::new([1u8; 32]),
            did: "did:nac:test".to_string(),
            stake_amount: 100_000_000_000,
            kyc_level: 2,
            hardware_score: 8000,
            constitution_score: 80,
            status: CbpStatus::Active,
            registered_at: 1000,
            last_active_at: 2000,
            blocks_produced: 100,
            reputation: 0.8,
        }
    }

    #[test]
    fn test_submit_exit_request() {
        let mut manager = ExitManager::new();
        let node = create_test_node();

        let result = manager.submit_exit_request(
            &node,
            ExitReason::Voluntary,
            3000,
        );
        assert!(result.is_ok());

        let request = manager.get_exit_request(&node.address).expect("FIX-006: unexpected None/Err");
        assert_eq!(request.status, ExitStatus::Pending);
        assert_eq!(request.reason, ExitReason::Voluntary);
    }

    #[test]
    fn test_duplicate_exit_request() {
        let mut manager = ExitManager::new();
        let node = create_test_node();

        manager.submit_exit_request(&node, ExitReason::Voluntary, 3000).expect("FIX-006: unexpected None/Err");
        let result = manager.submit_exit_request(&node, ExitReason::Voluntary, 3000);
        assert!(result.is_err());
    }

    #[test]
    fn test_review_exit_request() {
        let mut manager = ExitManager::new();
        let node = create_test_node();
        let reviewer = Address::new([2u8; 32]);

        manager.submit_exit_request(&node, ExitReason::Voluntary, 1000).expect("FIX-006: unexpected None/Err");

        // 审核（等待期满足）
        let result = manager.review_exit_request(
            &node.address,
            true,
            reviewer,
            Some("Approved".to_string()),
            1000 + 7 * 24 * 3600,
        );
        assert!(result.is_ok());

        let request = manager.get_exit_request(&node.address).expect("FIX-006: unexpected None/Err");
        assert_eq!(request.status, ExitStatus::Approved);
    }

    #[test]
    fn test_review_period_not_met() {
        let mut manager = ExitManager::new();
        let node = create_test_node();
        let reviewer = Address::new([2u8; 32]);

        manager.submit_exit_request(&node, ExitReason::Voluntary, 1000).expect("FIX-006: unexpected None/Err");

        // 审核（等待期不满足）
        let result = manager.review_exit_request(
            &node.address,
            true,
            reviewer,
            None,
            1000 + 3600, // 只过了1小时
        );
        assert!(result.is_err());
    }

    #[test]
    fn test_confirm_exit() {
        let mut manager = ExitManager::new();
        let node = create_test_node();
        let reviewer = Address::new([2u8; 32]);

        manager.submit_exit_request(&node, ExitReason::Voluntary, 1000).expect("FIX-006: unexpected None/Err");
        manager.review_exit_request(
            &node.address,
            true,
            reviewer,
            None,
            1000 + 7 * 24 * 3600,
        ).expect("FIX-006: unexpected None/Err");

        // 确认退出
        let result = manager.confirm_exit(
            &node.address,
            &node,
            95_000_000_000,
            5_000_000_000,
            1000 + 21 * 24 * 3600,
        );
        assert!(result.is_ok());

        let records = manager.get_exit_records(Some(&node.address));
        assert_eq!(records.len(), 1);
        assert_eq!(records[0].redemption_amount, 95_000_000_000);
    }

    #[test]
    fn test_cancel_exit_request() {
        let mut manager = ExitManager::new();
        let node = create_test_node();

        manager.submit_exit_request(&node, ExitReason::Voluntary, 1000).expect("FIX-006: unexpected None/Err");
        
        let result = manager.cancel_exit_request(&node.address);
        assert!(result.is_ok());

        let request = manager.get_exit_request(&node.address).expect("FIX-006: unexpected None/Err");
        assert_eq!(request.status, ExitStatus::Cancelled);
    }

    #[test]
    fn test_get_pending_requests() {
        let mut manager = ExitManager::new();
        let node1 = create_test_node();
        let mut node2 = create_test_node();
        node2.address = Address::new([2u8; 32]);

        manager.submit_exit_request(&node1, ExitReason::Voluntary, 1000).expect("FIX-006: unexpected None/Err");
        manager.submit_exit_request(&node2, ExitReason::HardwareFailure, 1000).expect("FIX-006: unexpected None/Err");

        let pending = manager.get_pending_requests();
        assert_eq!(pending.len(), 2);
    }

    #[test]
    fn test_exit_statistics() {
        let mut manager = ExitManager::new();
        let node = create_test_node();
        let reviewer = Address::new([2u8; 32]);

        manager.submit_exit_request(&node, ExitReason::Voluntary, 1000).expect("FIX-006: unexpected None/Err");
        manager.review_exit_request(&node.address, true, reviewer, None, 1000 + 7 * 24 * 3600).expect("FIX-006: unexpected None/Err");
        manager.confirm_exit(&node.address, &node, 95_000_000_000, 5_000_000_000, 1000 + 21 * 24 * 3600).expect("FIX-006: unexpected None/Err");

        let stats = manager.get_exit_statistics();
        assert_eq!(stats.total_exits, 1);
        assert_eq!(stats.voluntary_exits, 1);
        assert_eq!(stats.total_penalties, 5_000_000_000);
    }
}