// ACC-Custody: 资产托管协议（Custody Protocol）
//
// NAC原生的资产托管标准，用于多签托管和安全保管
// 100% NAC原生协议，不是任何现有标准的实现

use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// 托管状态
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum CustodyStatus {
    /// 活跃
    Active,
    /// 已暂停
    Suspended,
    /// 已终止
    Terminated,
    /// 待审核
    Pending,
}

/// 托管类型
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum CustodyType {
    /// 单一托管人
    Single,
    /// 多签托管（M-of-N）
    MultiSig { required: u8, total: u8 },
    /// 时间锁托管
    TimeLock { unlock_at: u64 },
    /// 条件托管
    Conditional,
}

/// 托管操作类型
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum CustodyOperation {
    /// 存入
    Deposit,
    /// 取出
    Withdraw,
    /// 转移
    Transfer,
    /// 暂停
    Suspend,
    /// 恢复
    Resume,
    /// 终止
    Terminate,
}

/// 托管记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CustodyRecord {
    /// 托管ID
    pub custody_id: String,
    /// 资产ID
    pub asset_id: String,
    /// 所有者地址
    pub owner: String,
    /// 托管人列表
    pub custodians: Vec<String>,
    /// 托管类型
    pub custody_type: CustodyType,
    /// 托管状态
    pub status: CustodyStatus,
    /// 创建时间
    pub created_at: u64,
    /// 更新时间
    pub updated_at: u64,
    /// 托管金额（如果是代币）
    pub amount: Option<u128>,
    /// 托管条件
    pub conditions: Vec<String>,
    /// 操作历史
    pub operations: Vec<CustodyOperationRecord>,
}

/// 托管操作记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CustodyOperationRecord {
    /// 操作类型
    pub operation: CustodyOperation,
    /// 操作发起人
    pub initiator: String,
    /// 签名列表
    pub signatures: Vec<String>,
    /// 操作时间
    pub timestamp: u64,
    /// 操作数据
    pub data: Option<String>,
}

/// 托管错误类型
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum CustodyError {
    /// 托管记录不存在
    RecordNotFound,
    /// 托管记录已存在
    RecordAlreadyExists,
    /// 资产不存在
    AssetNotFound,
    /// 未授权操作
    Unauthorized,
    /// 签名不足
    InsufficientSignatures,
    /// 托管已暂停
    CustodySuspended,
    /// 托管已终止
    CustodyTerminated,
    /// 时间锁未解锁
    TimeLockNotUnlocked,
    /// 条件未满足
    ConditionsNotMet,
    /// 无效的托管人
    InvalidCustodian,
}

/// 托管状态
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CustodyState {
    /// 托管记录映射 (custody_id -> CustodyRecord)
    pub custodies: HashMap<String, CustodyRecord>,
    /// 资产托管映射 (asset_id -> custody_id)
    pub asset_custodies: HashMap<String, String>,
    /// 所有者托管列表 (owner -> [custody_ids])
    pub owner_custodies: HashMap<String, Vec<String>>,
    /// 托管人托管列表 (custodian -> [custody_ids])
    pub custodian_custodies: HashMap<String, Vec<String>>,
}

/// ACC-Custody接口
pub trait ACCCustody {
    /// 创建托管
    fn create_custody(&mut self, record: CustodyRecord) -> Result<(), CustodyError>;

    /// 获取托管记录
    fn get_custody(&self, custody_id: &str) -> Result<CustodyRecord, CustodyError>;

    /// 获取资产的托管记录
    fn get_asset_custody(&self, asset_id: &str) -> Result<CustodyRecord, CustodyError>;

    /// 存入资产
    fn deposit(
        &mut self,
        custody_id: &str,
        initiator: &str,
        amount: Option<u128>,
    ) -> Result<(), CustodyError>;

    /// 取出资产
    fn withdraw(
        &mut self,
        custody_id: &str,
        initiator: &str,
        signatures: Vec<String>,
        amount: Option<u128>,
    ) -> Result<(), CustodyError>;

    /// 转移托管
    fn transfer_custody(
        &mut self,
        custody_id: &str,
        new_owner: String,
        signatures: Vec<String>,
    ) -> Result<(), CustodyError>;

    /// 暂停托管
    fn suspend_custody(
        &mut self,
        custody_id: &str,
        initiator: &str,
    ) -> Result<(), CustodyError>;

    /// 恢复托管
    fn resume_custody(&mut self, custody_id: &str, initiator: &str) -> Result<(), CustodyError>;

    /// 终止托管
    fn terminate_custody(
        &mut self,
        custody_id: &str,
        signatures: Vec<String>,
    ) -> Result<(), CustodyError>;

    /// 添加托管人
    fn add_custodian(&mut self, custody_id: &str, custodian: String) -> Result<(), CustodyError>;

    /// 移除托管人
    fn remove_custodian(&mut self, custody_id: &str, custodian: &str) -> Result<(), CustodyError>;

    /// 验证签名
    fn verify_signatures(&self, custody_id: &str, signatures: &[String]) -> bool;

    /// 获取所有者的托管列表
    fn get_owner_custodies(&self, owner: &str) -> Vec<CustodyRecord>;

    /// 获取托管人的托管列表
    fn get_custodian_custodies(&self, custodian: &str) -> Vec<CustodyRecord>;
}

/// ACC-Custody标准实现
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CustodyToken {
    state: CustodyState,
}

impl CustodyToken {
    /// 创建新的托管管理器
    pub fn new() -> Self {
        Self {
            state: CustodyState {
                custodies: HashMap::new(),
                asset_custodies: HashMap::new(),
                owner_custodies: HashMap::new(),
                custodian_custodies: HashMap::new(),
            },
        }
    }

    /// 获取状态的可变引用
    pub fn state_mut(&mut self) -> &mut CustodyState {
        &mut self.state
    }

    /// 获取状态的不可变引用
    pub fn state(&self) -> &CustodyState {
        &self.state
    }

    /// 检查托管状态
    fn check_custody_status(&self, record: &CustodyRecord) -> Result<(), CustodyError> {
        match record.status {
            CustodyStatus::Suspended => Err(CustodyError::CustodySuspended),
            CustodyStatus::Terminated => Err(CustodyError::CustodyTerminated),
            _ => Ok(()),
        }
    }

    /// 记录操作
    fn record_operation(
        &mut self,
        custody_id: &str,
        operation: CustodyOperation,
        initiator: &str,
        signatures: Vec<String>,
        data: Option<String>,
    ) -> Result<(), CustodyError> {
        let mut record = self.get_custody(custody_id)?;

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs();

        let op_record = CustodyOperationRecord {
            operation,
            initiator: initiator.to_string(),
            signatures,
            timestamp: now,
            data,
        };

        record.operations.push(op_record);
        record.updated_at = now;

        self.state
            .custodies
            .insert(custody_id.to_string(), record);

        Ok(())
    }
}

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

impl ACCCustody for CustodyToken {
    fn create_custody(&mut self, mut record: CustodyRecord) -> Result<(), CustodyError> {
        // 检查托管记录是否已存在
        if self.state.custodies.contains_key(&record.custody_id) {
            return Err(CustodyError::RecordAlreadyExists);
        }

        // 检查资产是否已被托管
        if self.state.asset_custodies.contains_key(&record.asset_id) {
            return Err(CustodyError::RecordAlreadyExists);
        }

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs();

        record.created_at = now;
        record.updated_at = now;
        record.status = CustodyStatus::Active;

        let custody_id = record.custody_id.clone();
        let asset_id = record.asset_id.clone();
        let owner = record.owner.clone();
        let custodians = record.custodians.clone();

        // 保存托管记录
        self.state.custodies.insert(custody_id.clone(), record);

        // 更新资产托管映射
        self.state
            .asset_custodies
            .insert(asset_id, custody_id.clone());

        // 更新所有者托管列表
        self.state
            .owner_custodies
            .entry(owner)
            .or_insert_with(Vec::new)
            .push(custody_id.clone());

        // 更新托管人托管列表
        for custodian in custodians {
            self.state
                .custodian_custodies
                .entry(custodian)
                .or_insert_with(Vec::new)
                .push(custody_id.clone());
        }

        Ok(())
    }

    fn get_custody(&self, custody_id: &str) -> Result<CustodyRecord, CustodyError> {
        self.state
            .custodies
            .get(custody_id)
            .cloned()
            .ok_or(CustodyError::RecordNotFound)
    }

    fn get_asset_custody(&self, asset_id: &str) -> Result<CustodyRecord, CustodyError> {
        let custody_id = self
            .state
            .asset_custodies
            .get(asset_id)
            .ok_or(CustodyError::AssetNotFound)?;
        self.get_custody(custody_id)
    }

    fn deposit(
        &mut self,
        custody_id: &str,
        initiator: &str,
        amount: Option<u128>,
    ) -> Result<(), CustodyError> {
        let record = self.get_custody(custody_id)?;
        self.check_custody_status(&record)?;

        self.record_operation(
            custody_id,
            CustodyOperation::Deposit,
            initiator,
            vec![],
            amount.map(|a| a.to_string()),
        )
    }

    fn withdraw(
        &mut self,
        custody_id: &str,
        initiator: &str,
        signatures: Vec<String>,
        amount: Option<u128>,
    ) -> Result<(), CustodyError> {
        let record = self.get_custody(custody_id)?;
        self.check_custody_status(&record)?;

        // 验证签名
        if !self.verify_signatures(custody_id, &signatures) {
            return Err(CustodyError::InsufficientSignatures);
        }

        self.record_operation(
            custody_id,
            CustodyOperation::Withdraw,
            initiator,
            signatures,
            amount.map(|a| a.to_string()),
        )
    }

    fn transfer_custody(
        &mut self,
        custody_id: &str,
        new_owner: String,
        signatures: Vec<String>,
    ) -> Result<(), CustodyError> {
        let mut record = self.get_custody(custody_id)?;
        self.check_custody_status(&record)?;

        // 验证签名
        if !self.verify_signatures(custody_id, &signatures) {
            return Err(CustodyError::InsufficientSignatures);
        }

        // 更新所有者
        let old_owner = record.owner.clone();
        record.owner = new_owner.clone();

        // 更新所有者托管列表
        if let Some(custodies) = self.state.owner_custodies.get_mut(&old_owner) {
            custodies.retain(|id| id != custody_id);
        }
        self.state
            .owner_custodies
            .entry(new_owner)
            .or_insert_with(Vec::new)
            .push(custody_id.to_string());

        self.state
            .custodies
            .insert(custody_id.to_string(), record);

        self.record_operation(
            custody_id,
            CustodyOperation::Transfer,
            &old_owner,
            signatures,
            None,
        )
    }

    fn suspend_custody(
        &mut self,
        custody_id: &str,
        initiator: &str,
    ) -> Result<(), CustodyError> {
        let mut record = self.get_custody(custody_id)?;
        record.status = CustodyStatus::Suspended;
        self.state
            .custodies
            .insert(custody_id.to_string(), record);

        self.record_operation(
            custody_id,
            CustodyOperation::Suspend,
            initiator,
            vec![],
            None,
        )
    }

    fn resume_custody(&mut self, custody_id: &str, initiator: &str) -> Result<(), CustodyError> {
        let mut record = self.get_custody(custody_id)?;
        record.status = CustodyStatus::Active;
        self.state
            .custodies
            .insert(custody_id.to_string(), record);

        self.record_operation(
            custody_id,
            CustodyOperation::Resume,
            initiator,
            vec![],
            None,
        )
    }

    fn terminate_custody(
        &mut self,
        custody_id: &str,
        signatures: Vec<String>,
    ) -> Result<(), CustodyError> {
        let mut record = self.get_custody(custody_id)?;

        // 验证签名
        if !self.verify_signatures(custody_id, &signatures) {
            return Err(CustodyError::InsufficientSignatures);
        }

        record.status = CustodyStatus::Terminated;
        self.state
            .custodies
            .insert(custody_id.to_string(), record);

        self.record_operation(
            custody_id,
            CustodyOperation::Terminate,
            "",
            signatures,
            None,
        )
    }

    fn add_custodian(&mut self, custody_id: &str, custodian: String) -> Result<(), CustodyError> {
        let mut record = self.get_custody(custody_id)?;

        if !record.custodians.contains(&custodian) {
            record.custodians.push(custodian.clone());
            self.state
                .custodies
                .insert(custody_id.to_string(), record);

            // 更新托管人托管列表
            self.state
                .custodian_custodies
                .entry(custodian)
                .or_insert_with(Vec::new)
                .push(custody_id.to_string());
        }

        Ok(())
    }

    fn remove_custodian(&mut self, custody_id: &str, custodian: &str) -> Result<(), CustodyError> {
        let mut record = self.get_custody(custody_id)?;
        record.custodians.retain(|c| c != custodian);
        self.state
            .custodies
            .insert(custody_id.to_string(), record);

        // 更新托管人托管列表
        if let Some(custodies) = self.state.custodian_custodies.get_mut(custodian) {
            custodies.retain(|id| id != custody_id);
        }

        Ok(())
    }

    fn verify_signatures(&self, custody_id: &str, signatures: &[String]) -> bool {
        if let Ok(record) = self.get_custody(custody_id) {
            match &record.custody_type {
                CustodyType::Single => signatures.len() >= 1,
                CustodyType::MultiSig { required, .. } => {
                    signatures.len() >= *required as usize
                }
                CustodyType::TimeLock { unlock_at } => {
                    let now = std::time::SystemTime::now()
                        .duration_since(std::time::UNIX_EPOCH)
                        .unwrap()
                        .as_secs();
                    now >= *unlock_at
                }
                CustodyType::Conditional => true, // 简化实现
            }
        } else {
            false
        }
    }

    fn get_owner_custodies(&self, owner: &str) -> Vec<CustodyRecord> {
        self.state
            .owner_custodies
            .get(owner)
            .map(|custody_ids| {
                custody_ids
                    .iter()
                    .filter_map(|id| self.state.custodies.get(id).cloned())
                    .collect()
            })
            .unwrap_or_default()
    }

    fn get_custodian_custodies(&self, custodian: &str) -> Vec<CustodyRecord> {
        self.state
            .custodian_custodies
            .get(custodian)
            .map(|custody_ids| {
                custody_ids
                    .iter()
                    .filter_map(|id| self.state.custodies.get(id).cloned())
                    .collect()
            })
            .unwrap_or_default()
    }
}

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

    fn create_test_record() -> CustodyRecord {
        CustodyRecord {
            custody_id: "CUSTODY-001".to_string(),
            asset_id: "RWA-001".to_string(),
            owner: "alice".to_string(),
            custodians: vec!["custodian1".to_string(), "custodian2".to_string()],
            custody_type: CustodyType::MultiSig {
                required: 2,
                total: 2,
            },
            status: CustodyStatus::Active,
            created_at: 0,
            updated_at: 0,
            amount: Some(1000000),
            conditions: Vec::new(),
            operations: Vec::new(),
        }
    }

    #[test]
    fn test_create_custody() {
        let mut custody = CustodyToken::new();
        let record = create_test_record();
        assert!(custody.create_custody(record).is_ok());
    }

    #[test]
    fn test_deposit() {
        let mut custody = CustodyToken::new();
        let record = create_test_record();
        custody.create_custody(record).unwrap();

        assert!(custody
            .deposit("CUSTODY-001", "alice", Some(500000))
            .is_ok());
    }

    #[test]
    fn test_withdraw() {
        let mut custody = CustodyToken::new();
        let record = create_test_record();
        custody.create_custody(record).unwrap();

        let signatures = vec!["sig1".to_string(), "sig2".to_string()];
        assert!(custody
            .withdraw("CUSTODY-001", "alice", signatures, Some(500000))
            .is_ok());
    }

    #[test]
    fn test_suspend_and_resume() {
        let mut custody = CustodyToken::new();
        let record = create_test_record();
        custody.create_custody(record).unwrap();

        assert!(custody.suspend_custody("CUSTODY-001", "alice").is_ok());
        assert_eq!(
            custody.get_custody("CUSTODY-001").unwrap().status,
            CustodyStatus::Suspended
        );

        assert!(custody.resume_custody("CUSTODY-001", "alice").is_ok());
        assert_eq!(
            custody.get_custody("CUSTODY-001").unwrap().status,
            CustodyStatus::Active
        );
    }

    #[test]
    fn test_add_remove_custodian() {
        let mut custody = CustodyToken::new();
        let record = create_test_record();
        custody.create_custody(record).unwrap();

        assert!(custody
            .add_custodian("CUSTODY-001", "custodian3".to_string())
            .is_ok());
        assert_eq!(
            custody.get_custody("CUSTODY-001").unwrap().custodians.len(),
            3
        );

        assert!(custody
            .remove_custodian("CUSTODY-001", "custodian3")
            .is_ok());
        assert_eq!(
            custody.get_custody("CUSTODY-001").unwrap().custodians.len(),
            2
        );
    }
}