// ACC-Insurance: 资产保险协议（Insurance Protocol）
//
// NAC原生的资产保险标准，用于风险管理和保险保障
// 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;

/// 保险状态
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum InsuranceStatus {
    /// 活跃
    Active,
    /// 已暂停
    Suspended,
    /// 已过期
    Expired,
    /// 已终止
    Terminated,
}

/// 理赔状态
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum ClaimStatus {
    /// 待审核
    Pending,
    /// 审核中
    UnderReview,
    /// 已批准
    Approved,
    /// 已拒绝
    Rejected,
    /// 已支付
    Paid,
}

/// 保险类型
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum InsuranceType {
    /// 财产保险
    Property,
    /// 责任保险
    Liability,
    /// 信用保险
    Credit,
    /// 智能合约保险
    SmartContract,
    /// 其他
    Other(String),
}

/// 保险策略
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InsurancePolicy {
    /// 保单ID
    pub policy_id: String,
    /// 资产ID
    pub asset_id: String,
    /// 被保险人地址
    pub insured: String,
    /// 保险公司地址
    pub insurer: String,
    /// 保险类型
    pub insurance_type: InsuranceType,
    /// 保险金额（USD，以分为单位）
    pub coverage_amount: u128,
    /// 保费（USD，以分为单位）
    pub premium: u128,
    /// 免赔额（USD，以分为单位）
    pub deductible: u128,
    /// 保险状态
    pub status: InsuranceStatus,
    /// 生效时间
    pub effective_date: u64,
    /// 到期时间
    pub expiration_date: u64,
    /// 创建时间
    pub created_at: u64,
    /// 更新时间
    pub updated_at: u64,
    /// 保险条款
    pub terms: Vec<String>,
}

/// 理赔申请
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ClaimRequest {
    /// 理赔ID
    pub claim_id: String,
    /// 保单ID
    pub policy_id: String,
    /// 申请人地址
    pub claimant: String,
    /// 理赔金额（USD，以分为单位）
    pub claim_amount: u128,
    /// 理赔状态
    pub status: ClaimStatus,
    /// 申请时间
    pub filed_at: u64,
    /// 批准时间
    pub approved_at: Option<u64>,
    /// 支付时间
    pub paid_at: Option<u64>,
    /// 实际赔付金额
    pub payout_amount: Option<u128>,
    /// 理赔描述
    pub description: String,
    /// 证据哈希列表
    pub evidence_hashes: Vec<[u8; 32]>,
    /// 审核备注
    pub notes: Vec<String>,
}

/// 保险错误类型
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum InsuranceError {
    /// 保单不存在
    PolicyNotFound,
    /// 保单已存在
    PolicyAlreadyExists,
    /// 理赔申请不存在
    ClaimNotFound,
    /// 理赔申请已存在
    ClaimAlreadyExists,
    /// 保单已过期
    PolicyExpired,
    /// 保单已暂停
    PolicySuspended,
    /// 理赔金额超过保险金额
    ClaimExceedsCoverage,
    /// 未授权操作
    Unauthorized,
    /// 保费未支付
    PremiumNotPaid,
}

/// 保险状态
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InsuranceState {
    /// 保单映射 (policy_id -> InsurancePolicy)
    pub policies: HashMap<String, InsurancePolicy>,
    /// 资产保单映射 (asset_id -> policy_id)
    pub asset_policies: HashMap<String, String>,
    /// 被保险人保单列表 (insured -> [policy_ids])
    pub insured_policies: HashMap<String, Vec<String>>,
    /// 理赔申请映射 (claim_id -> ClaimRequest)
    pub claims: HashMap<String, ClaimRequest>,
    /// 保单理赔列表 (policy_id -> [claim_ids])
    pub policy_claims: HashMap<String, Vec<String>>,
}

/// ACC-Insurance接口
pub trait ACCInsurance {
    /// 创建保单
    fn create_policy(&mut self, policy: InsurancePolicy) -> Result<(), InsuranceError>;

    /// 获取保单
    fn get_policy(&self, policy_id: &str) -> Result<InsurancePolicy, InsuranceError>;

    /// 获取资产的保单
    fn get_asset_policy(&self, asset_id: &str) -> Result<InsurancePolicy, InsuranceError>;

    /// 提交理赔申请
    fn file_claim(&mut self, claim: ClaimRequest) -> Result<(), InsuranceError>;

    /// 获取理赔申请
    fn get_claim(&self, claim_id: &str) -> Result<ClaimRequest, InsuranceError>;

    /// 批准理赔
    fn approve_claim(&mut self, claim_id: &str, payout_amount: u128) -> Result<(), InsuranceError>;

    /// 拒绝理赔
    fn reject_claim(&mut self, claim_id: &str, reason: String) -> Result<(), InsuranceError>;

    /// 支付理赔
    fn pay_claim(&mut self, claim_id: &str) -> Result<(), InsuranceError>;

    /// 续保
    fn renew_policy(&mut self, policy_id: &str, new_expiration: u64) -> Result<(), InsuranceError>;

    /// 暂停保单
    fn suspend_policy(&mut self, policy_id: &str) -> Result<(), InsuranceError>;

    /// 恢复保单
    fn resume_policy(&mut self, policy_id: &str) -> Result<(), InsuranceError>;

    /// 终止保单
    fn terminate_policy(&mut self, policy_id: &str) -> Result<(), InsuranceError>;

    /// 获取被保险人的保单列表
    fn get_insured_policies(&self, insured: &str) -> Vec<InsurancePolicy>;

    /// 获取保单的理赔历史
    fn get_policy_claims(&self, policy_id: &str) -> Vec<ClaimRequest>;

    /// 检查保单是否有效
    fn is_policy_valid(&self, policy_id: &str) -> bool;
}

/// ACC-Insurance标准实现
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InsuranceToken {
    state: InsuranceState,
}

impl InsuranceToken {
    /// 创建新的保险管理器
    pub fn new() -> Self {
        Self {
            state: InsuranceState {
                policies: HashMap::new(),
                asset_policies: HashMap::new(),
                insured_policies: HashMap::new(),
                claims: HashMap::new(),
                policy_claims: HashMap::new(),
            },
        }
    }

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

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

    /// 检查保单状态
    fn check_policy_status(&self, policy: &InsurancePolicy) -> Result<(), InsuranceError> {
        match policy.status {
            InsuranceStatus::Expired => Err(InsuranceError::PolicyExpired),
            InsuranceStatus::Suspended => Err(InsuranceError::PolicySuspended),
            InsuranceStatus::Terminated => Err(InsuranceError::PolicyExpired),
            _ => Ok(()),
        }
    }
}

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

impl ACCInsurance for InsuranceToken {
    fn create_policy(&mut self, mut policy: InsurancePolicy) -> Result<(), InsuranceError> {
        // 检查保单是否已存在
        if self.state.policies.contains_key(&policy.policy_id) {
            return Err(InsuranceError::PolicyAlreadyExists);
        }

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        policy.created_at = now;
        policy.updated_at = now;
        policy.status = InsuranceStatus::Active;

        let policy_id = policy.policy_id.clone();
        let asset_id = policy.asset_id.clone();
        let insured = policy.insured.clone();

        // 保存保单
        self.state.policies.insert(policy_id.clone(), policy);

        // 更新资产保单映射
        self.state
            .asset_policies
            .insert(asset_id, policy_id.clone());

        // 更新被保险人保单列表
        self.state
            .insured_policies
            .entry(insured)
            .or_insert_with(Vec::new)
            .push(policy_id);

        Ok(())
    }

    fn get_policy(&self, policy_id: &str) -> Result<InsurancePolicy, InsuranceError> {
        self.state
            .policies
            .get(policy_id)
            .cloned()
            .ok_or(InsuranceError::PolicyNotFound)
    }

    fn get_asset_policy(&self, asset_id: &str) -> Result<InsurancePolicy, InsuranceError> {
        let policy_id = self
            .state
            .asset_policies
            .get(asset_id)
            .ok_or(InsuranceError::PolicyNotFound)?;
        self.get_policy(policy_id)
    }

    fn file_claim(&mut self, mut claim: ClaimRequest) -> Result<(), InsuranceError> {
        // 检查理赔申请是否已存在
        if self.state.claims.contains_key(&claim.claim_id) {
            return Err(InsuranceError::ClaimAlreadyExists);
        }

        // 获取保单并检查状态
        let policy = self.get_policy(&claim.policy_id)?;
        self.check_policy_status(&policy)?;

        // 检查理赔金额
        if claim.claim_amount > policy.coverage_amount {
            return Err(InsuranceError::ClaimExceedsCoverage);
        }

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        claim.filed_at = now;
        claim.status = ClaimStatus::Pending;

        let claim_id = claim.claim_id.clone();
        let policy_id = claim.policy_id.clone();

        // 保存理赔申请
        self.state.claims.insert(claim_id.clone(), claim);

        // 更新保单理赔列表
        self.state
            .policy_claims
            .entry(policy_id)
            .or_insert_with(Vec::new)
            .push(claim_id);

        Ok(())
    }

    fn get_claim(&self, claim_id: &str) -> Result<ClaimRequest, InsuranceError> {
        self.state
            .claims
            .get(claim_id)
            .cloned()
            .ok_or(InsuranceError::ClaimNotFound)
    }

    fn approve_claim(&mut self, claim_id: &str, payout_amount: u128) -> Result<(), InsuranceError> {
        let mut claim = self.get_claim(claim_id)?;

        if claim.status != ClaimStatus::Pending && claim.status != ClaimStatus::UnderReview {
            return Err(InsuranceError::Unauthorized);
        }

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        claim.status = ClaimStatus::Approved;
        claim.approved_at = Some(now);
        claim.payout_amount = Some(payout_amount);

        self.state.claims.insert(claim_id.to_string(), claim);

        Ok(())
    }

    fn reject_claim(&mut self, claim_id: &str, reason: String) -> Result<(), InsuranceError> {
        let mut claim = self.get_claim(claim_id)?;

        if claim.status != ClaimStatus::Pending && claim.status != ClaimStatus::UnderReview {
            return Err(InsuranceError::Unauthorized);
        }

        claim.status = ClaimStatus::Rejected;
        claim.notes.push(format!("Rejected: {}", reason));

        self.state.claims.insert(claim_id.to_string(), claim);

        Ok(())
    }

    fn pay_claim(&mut self, claim_id: &str) -> Result<(), InsuranceError> {
        let mut claim = self.get_claim(claim_id)?;

        if claim.status != ClaimStatus::Approved {
            return Err(InsuranceError::Unauthorized);
        }

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        claim.status = ClaimStatus::Paid;
        claim.paid_at = Some(now);

        self.state.claims.insert(claim_id.to_string(), claim);

        Ok(())
    }

    fn renew_policy(&mut self, policy_id: &str, new_expiration: u64) -> Result<(), InsuranceError> {
        let mut policy = self.get_policy(policy_id)?;

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        policy.expiration_date = new_expiration;
        policy.status = InsuranceStatus::Active;
        policy.updated_at = now;

        self.state.policies.insert(policy_id.to_string(), policy);

        Ok(())
    }

    fn suspend_policy(&mut self, policy_id: &str) -> Result<(), InsuranceError> {
        let mut policy = self.get_policy(policy_id)?;

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        policy.status = InsuranceStatus::Suspended;
        policy.updated_at = now;

        self.state.policies.insert(policy_id.to_string(), policy);

        Ok(())
    }

    fn resume_policy(&mut self, policy_id: &str) -> Result<(), InsuranceError> {
        let mut policy = self.get_policy(policy_id)?;

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        policy.status = InsuranceStatus::Active;
        policy.updated_at = now;

        self.state.policies.insert(policy_id.to_string(), policy);

        Ok(())
    }

    fn terminate_policy(&mut self, policy_id: &str) -> Result<(), InsuranceError> {
        let mut policy = self.get_policy(policy_id)?;

        let now = std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .expect("mainnet: handle error")
            .as_secs();

        policy.status = InsuranceStatus::Terminated;
        policy.updated_at = now;

        self.state.policies.insert(policy_id.to_string(), policy);

        Ok(())
    }

    fn get_insured_policies(&self, insured: &str) -> Vec<InsurancePolicy> {
        self.state
            .insured_policies
            .get(insured)
            .map(|policy_ids| {
                policy_ids
                    .iter()
                    .filter_map(|id| self.state.policies.get(id).cloned())
                    .collect()
            })
            .unwrap_or_default()
    }

    fn get_policy_claims(&self, policy_id: &str) -> Vec<ClaimRequest> {
        self.state
            .policy_claims
            .get(policy_id)
            .map(|claim_ids| {
                claim_ids
                    .iter()
                    .filter_map(|id| self.state.claims.get(id).cloned())
                    .collect()
            })
            .unwrap_or_default()
    }

    fn is_policy_valid(&self, policy_id: &str) -> bool {
        if let Ok(policy) = self.get_policy(policy_id) {
            let now = std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .expect("mainnet: handle error")
                .as_secs();
            policy.status == InsuranceStatus::Active && now < policy.expiration_date
        } else {
            false
        }
    }
}

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

    fn create_test_policy() -> InsurancePolicy {
        InsurancePolicy {
            policy_id: "POL-001".to_string(),
            asset_id: "RWA-001".to_string(),
            insured: "alice".to_string(),
            insurer: "insurer1".to_string(),
            insurance_type: InsuranceType::Property,
            coverage_amount: 1000000_00,
            premium: 10000_00,
            deductible: 5000_00,
            status: InsuranceStatus::Active,
            effective_date: 1234567890,
            expiration_date: 1234567890 + 31536000,
            created_at: 0,
            updated_at: 0,
            terms: vec!["Term 1".to_string(), "Term 2".to_string()],
        }
    }

    fn create_test_claim() -> ClaimRequest {
        ClaimRequest {
            claim_id: "CLAIM-001".to_string(),
            policy_id: "POL-001".to_string(),
            claimant: "alice".to_string(),
            claim_amount: 50000_00,
            status: ClaimStatus::Pending,
            filed_at: 0,
            approved_at: None,
            paid_at: None,
            payout_amount: None,
            description: "Test claim".to_string(),
            evidence_hashes: vec![[1u8; 32]],
            notes: Vec::new(),
        }
    }

    #[test]
    fn test_create_policy() {
        let mut insurance = InsuranceToken::new();
        let policy = create_test_policy();
        assert!(insurance.create_policy(policy).is_ok());
    }

    #[test]
    fn test_file_claim() {
        let mut insurance = InsuranceToken::new();
        let policy = create_test_policy();
        insurance.create_policy(policy).expect("mainnet: handle error");

        let claim = create_test_claim();
        assert!(insurance.file_claim(claim).is_ok());
    }

    #[test]
    fn test_approve_and_pay_claim() {
        let mut insurance = InsuranceToken::new();
        let policy = create_test_policy();
        insurance.create_policy(policy).expect("mainnet: handle error");

        let claim = create_test_claim();
        insurance.file_claim(claim).expect("mainnet: handle error");

        assert!(insurance.approve_claim("CLAIM-001", 45000_00).is_ok());
        assert_eq!(
            insurance.get_claim("CLAIM-001").expect("mainnet: handle error").status,
            ClaimStatus::Approved
        );

        assert!(insurance.pay_claim("CLAIM-001").is_ok());
        assert_eq!(
            insurance.get_claim("CLAIM-001").expect("mainnet: handle error").status,
            ClaimStatus::Paid
        );
    }

    #[test]
    fn test_renew_policy() {
        let mut insurance = InsuranceToken::new();
        let policy = create_test_policy();
        insurance.create_policy(policy).expect("mainnet: handle error");

        let new_expiration = 1234567890 + 63072000; // 2 years
        assert!(insurance.renew_policy("POL-001", new_expiration).is_ok());
        assert_eq!(
            insurance.get_policy("POL-001").expect("mainnet: handle error").expiration_date,
            new_expiration
        );
    }

    #[test]
    fn test_suspend_and_resume_policy() {
        let mut insurance = InsuranceToken::new();
        let policy = create_test_policy();
        insurance.create_policy(policy).expect("mainnet: handle error");

        assert!(insurance.suspend_policy("POL-001").is_ok());
        assert_eq!(
            insurance.get_policy("POL-001").expect("mainnet: handle error").status,
            InsuranceStatus::Suspended
        );

        assert!(insurance.resume_policy("POL-001").is_ok());
        assert_eq!(
            insurance.get_policy("POL-001").expect("mainnet: handle error").status,
            InsuranceStatus::Active
        );
    }
}