//! 投票权系统
//! 
//! 实现证券型资产的投票机制、权重计算、投票记录和结果统计

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

/// 投票提案
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Proposal {
    /// 提案ID
    pub id: String,
    /// 提案标题
    pub title: String,
    /// 提案描述
    pub description: String,
    /// 提案类型
    pub proposal_type: ProposalType,
    /// 创建者
    pub creator: String,
    /// 创建时间
    pub created_at: u64,
    /// 投票开始时间
    pub voting_start: u64,
    /// 投票结束时间
    pub voting_end: u64,
    /// 状态
    pub status: ProposalStatus,
    /// 需要的最小投票率（百分比）
    pub quorum_percentage: u8,
    /// 需要的赞成率（百分比）
    pub approval_percentage: u8,
    /// 证券分区ID
    pub security_id: [u8; 32],
}

/// 提案类型
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum ProposalType {
    /// 董事会选举
    BoardElection,
    /// 章程修改
    CharterAmendment,
    /// 重大交易
    MajorTransaction,
    /// 股息分配
    DividendDistribution,
    /// 资产重组
    Restructuring,
    /// 其他
    Other,
}

/// 提案状态
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum ProposalStatus {
    /// 草案
    Draft,
    /// 投票中
    Active,
    /// 已通过
    Passed,
    /// 未通过
    Rejected,
    /// 已取消
    Cancelled,
    /// 已执行
    Executed,
}

/// 投票选项
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum VoteOption {
    /// 赞成
    For,
    /// 反对
    Against,
    /// 弃权
    Abstain,
}

/// 投票记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VoteRecord {
    /// 提案ID
    pub proposal_id: String,
    /// 投票人
    pub voter: String,
    /// 投票选项
    pub option: VoteOption,
    /// 持股数量
    pub shares: u64,
    /// 投票权重（考虑投票倍数）
    pub voting_power: u64,
    /// 投票时间
    pub timestamp: u64,
    /// 是否为代理投票
    pub is_proxy: bool,
    /// 代理人（如果是代理投票）
    pub proxy: Option<String>,
}

/// 投票结果
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VotingResult {
    /// 提案ID
    pub proposal_id: String,
    /// 赞成票数
    pub votes_for: u64,
    /// 反对票数
    pub votes_against: u64,
    /// 弃权票数
    pub votes_abstain: u64,
    /// 总投票权重
    pub total_voting_power: u64,
    /// 总股份数
    pub total_shares: u64,
    /// 投票率（百分比）
    pub turnout_percentage: u8,
    /// 赞成率（百分比，基于有效票）
    pub approval_percentage: u8,
    /// 是否达到法定人数
    pub quorum_reached: bool,
    /// 是否通过
    pub passed: bool,
}

/// 投票权配置
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VotingRights {
    /// 账户地址
    pub account: String,
    /// 持股数量
    pub shares: u64,
    /// 投票倍数（例如：优先股可能有更高的投票权）
    pub voting_multiplier: u32,
    /// 是否被限制投票
    pub restricted: bool,
    /// 限制原因
    pub restriction_reason: Option<String>,
}

/// 代理投票授权
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ProxyAuthorization {
    /// 授权人
    pub principal: String,
    /// 代理人
    pub proxy: String,
    /// 授权的提案ID（如果为None则表示全部提案）
    pub proposal_id: Option<String>,
    /// 授权开始时间
    pub valid_from: u64,
    /// 授权结束时间
    pub valid_until: u64,
    /// 是否已撤销
    pub revoked: bool,
}

/// 投票系统
#[derive(Debug)]
pub struct VotingSystem {
    /// 提案列表
    proposals: HashMap<String, Proposal>,
    /// 投票记录
    votes: HashMap<String, Vec<VoteRecord>>,
    /// 投票权配置
    voting_rights: HashMap<String, VotingRights>,
    /// 代理授权
    proxy_authorizations: Vec<ProxyAuthorization>,
    /// 下一个提案ID
    next_proposal_id: u64,
}

impl VotingSystem {
    /// 创建新的投票系统
    pub fn new() -> Self {
        Self {
            proposals: HashMap::new(),
            votes: HashMap::new(),
            voting_rights: HashMap::new(),
            proxy_authorizations: Vec::new(),
            next_proposal_id: 1,
        }
    }

    /// 创建提案
    pub fn create_proposal(
        &mut self,
        title: String,
        description: String,
        proposal_type: ProposalType,
        creator: String,
        security_id: [u8; 32],
        voting_start: u64,
        voting_end: u64,
        quorum_percentage: u8,
        approval_percentage: u8,
    ) -> Result<String, String> {
        // 验证参数
        if title.is_empty() {
            return Err("Title cannot be empty".to_string());
        }

        if voting_start >= voting_end {
            return Err("Voting start must be before voting end".to_string());
        }

        if quorum_percentage > 100 || approval_percentage > 100 {
            return Err("Percentages must be between 0 and 100".to_string());
        }

        let current_time = Self::current_timestamp();
        if voting_start < current_time {
            return Err("Voting start must be in the future".to_string());
        }

        // 生成提案ID
        let proposal_id = format!("PROP-{:08}", self.next_proposal_id);
        self.next_proposal_id += 1;

        // 创建提案
        let proposal = Proposal {
            id: proposal_id.clone(),
            title,
            description,
            proposal_type,
            creator,
            created_at: current_time,
            voting_start,
            voting_end,
            status: ProposalStatus::Draft,
            quorum_percentage,
            approval_percentage,
            security_id,
        };

        self.proposals.insert(proposal_id.clone(), proposal);
        self.votes.insert(proposal_id.clone(), Vec::new());

        Ok(proposal_id)
    }

    /// 激活提案（开始投票）
    pub fn activate_proposal(&mut self, proposal_id: &str) -> Result<(), String> {
        let proposal = self.proposals.get_mut(proposal_id)
            .ok_or_else(|| "Proposal not found".to_string())?;

        if proposal.status != ProposalStatus::Draft {
            return Err(format!("Proposal is not in draft status: {:?}", proposal.status));
        }

        let current_time = Self::current_timestamp();
        if current_time < proposal.voting_start {
            return Err("Voting period has not started yet".to_string());
        }

        proposal.status = ProposalStatus::Active;
        Ok(())
    }

    /// 设置投票权
    pub fn set_voting_rights(
        &mut self,
        account: String,
        shares: u64,
        voting_multiplier: u32,
    ) {
        let rights = VotingRights {
            account: account.clone(),
            shares,
            voting_multiplier,
            restricted: false,
            restriction_reason: None,
        };

        self.voting_rights.insert(account, rights);
    }

    /// 限制投票权
    pub fn restrict_voting(&mut self, account: &str, reason: String) -> Result<(), String> {
        let rights = self.voting_rights.get_mut(account)
            .ok_or_else(|| "Account not found".to_string())?;

        rights.restricted = true;
        rights.restriction_reason = Some(reason);
        Ok(())
    }

    /// 恢复投票权
    pub fn unrestrict_voting(&mut self, account: &str) -> Result<(), String> {
        let rights = self.voting_rights.get_mut(account)
            .ok_or_else(|| "Account not found".to_string())?;

        rights.restricted = false;
        rights.restriction_reason = None;
        Ok(())
    }

    /// 授权代理投票
    pub fn authorize_proxy(
        &mut self,
        principal: String,
        proxy: String,
        proposal_id: Option<String>,
        valid_from: u64,
        valid_until: u64,
    ) -> Result<(), String> {
        if principal == proxy {
            return Err("Cannot authorize self as proxy".to_string());
        }

        if valid_from >= valid_until {
            return Err("Valid from must be before valid until".to_string());
        }

        // 检查是否已存在相同的授权
        for auth in &self.proxy_authorizations {
            if auth.principal == principal 
                && auth.proxy == proxy 
                && auth.proposal_id == proposal_id 
                && !auth.revoked {
                return Err("Proxy authorization already exists".to_string());
            }
        }

        let authorization = ProxyAuthorization {
            principal,
            proxy,
            proposal_id,
            valid_from,
            valid_until,
            revoked: false,
        };

        self.proxy_authorizations.push(authorization);
        Ok(())
    }

    /// 撤销代理授权
    pub fn revoke_proxy(
        &mut self,
        principal: &str,
        proxy: &str,
        proposal_id: Option<&str>,
    ) -> Result<(), String> {
        let mut found = false;

        for auth in &mut self.proxy_authorizations {
            if auth.principal == principal 
                && auth.proxy == proxy 
                && auth.proposal_id.as_deref() == proposal_id 
                && !auth.revoked {
                auth.revoked = true;
                found = true;
            }
        }

        if found {
            Ok(())
        } else {
            Err("Proxy authorization not found".to_string())
        }
    }

    /// 检查代理授权是否有效
    fn is_proxy_valid(
        &self,
        principal: &str,
        proxy: &str,
        proposal_id: &str,
    ) -> bool {
        let current_time = Self::current_timestamp();

        self.proxy_authorizations.iter().any(|auth| {
            auth.principal == principal
                && auth.proxy == proxy
                && !auth.revoked
                && auth.valid_from <= current_time
                && auth.valid_until >= current_time
                && (auth.proposal_id.is_none() || auth.proposal_id.as_deref() == Some(proposal_id))
        })
    }

    /// 投票
    pub fn cast_vote(
        &mut self,
        proposal_id: &str,
        voter: &str,
        option: VoteOption,
        as_proxy_for: Option<&str>,
    ) -> Result<(), String> {
        // 检查提案是否存在
        let proposal = self.proposals.get(proposal_id)
            .ok_or_else(|| "Proposal not found".to_string())?;

        // 检查提案状态
        if proposal.status != ProposalStatus::Active {
            return Err(format!("Proposal is not active: {:?}", proposal.status));
        }

        // 检查投票时间
        let current_time = Self::current_timestamp();
        if current_time < proposal.voting_start {
            return Err("Voting has not started yet".to_string());
        }
        if current_time > proposal.voting_end {
            return Err("Voting has ended".to_string());
        }

        // 确定实际投票人
        let actual_voter = if let Some(principal) = as_proxy_for {
            // 代理投票：检查授权
            if !self.is_proxy_valid(principal, voter, proposal_id) {
                return Err("Proxy authorization is not valid".to_string());
            }
            principal
        } else {
            voter
        };

        // 检查是否已投票
        let votes = self.votes.get(proposal_id).unwrap();
        if votes.iter().any(|v| v.voter == actual_voter) {
            return Err("Already voted on this proposal".to_string());
        }

        // 获取投票权
        let rights = self.voting_rights.get(actual_voter)
            .ok_or_else(|| "Voter has no voting rights".to_string())?;

        // 检查是否被限制
        if rights.restricted {
            return Err(format!(
                "Voting rights restricted: {}",
                rights.restriction_reason.as_deref().unwrap_or("Unknown reason")
            ));
        }

        // 计算投票权重
        let voting_power = rights.shares as u64 * rights.voting_multiplier as u64;

        // 创建投票记录
        let vote_record = VoteRecord {
            proposal_id: proposal_id.to_string(),
            voter: actual_voter.to_string(),
            option,
            shares: rights.shares,
            voting_power,
            timestamp: current_time,
            is_proxy: as_proxy_for.is_some(),
            proxy: as_proxy_for.map(|_| voter.to_string()),
        };

        // 添加投票记录
        self.votes.get_mut(proposal_id).unwrap().push(vote_record);

        Ok(())
    }

    /// 计算投票结果
    pub fn calculate_result(&self, proposal_id: &str) -> Result<VotingResult, String> {
        let proposal = self.proposals.get(proposal_id)
            .ok_or_else(|| "Proposal not found".to_string())?;

        let votes = self.votes.get(proposal_id)
            .ok_or_else(|| "No votes found".to_string())?;

        // 统计各选项的票数
        let mut votes_for = 0u64;
        let mut votes_against = 0u64;
        let mut votes_abstain = 0u64;

        for vote in votes {
            match vote.option {
                VoteOption::For => votes_for += vote.voting_power,
                VoteOption::Against => votes_against += vote.voting_power,
                VoteOption::Abstain => votes_abstain += vote.voting_power,
            }
        }

        // 计算总投票权重
        let total_voting_power = votes_for + votes_against + votes_abstain;

        // 计算总股份数（所有有投票权的股份）
        let total_shares: u64 = self.voting_rights.values()
            .filter(|r| !r.restricted)
            .map(|r| r.shares as u64 * r.voting_multiplier as u64)
            .sum();

        // 计算投票率
        let turnout_percentage = if total_shares > 0 {
            ((total_voting_power * 100) / total_shares) as u8
        } else {
            0
        };

        // 计算赞成率（基于有效票：赞成+反对）
        let effective_votes = votes_for + votes_against;
        let approval_percentage = if effective_votes > 0 {
            ((votes_for * 100) / effective_votes) as u8
        } else {
            0
        };

        // 检查是否达到法定人数
        let quorum_reached = turnout_percentage >= proposal.quorum_percentage;

        // 检查是否通过
        let passed = quorum_reached && approval_percentage >= proposal.approval_percentage;

        Ok(VotingResult {
            proposal_id: proposal_id.to_string(),
            votes_for,
            votes_against,
            votes_abstain,
            total_voting_power,
            total_shares,
            turnout_percentage,
            approval_percentage,
            quorum_reached,
            passed,
        })
    }

    /// 结束投票并更新提案状态
    pub fn finalize_proposal(&mut self, proposal_id: &str) -> Result<VotingResult, String> {
        let proposal = self.proposals.get_mut(proposal_id)
            .ok_or_else(|| "Proposal not found".to_string())?;

        if proposal.status != ProposalStatus::Active {
            return Err(format!("Proposal is not active: {:?}", proposal.status));
        }

        let current_time = Self::current_timestamp();
        if current_time < proposal.voting_end {
            return Err("Voting period has not ended yet".to_string());
        }

        // 计算结果
        let result = self.calculate_result(proposal_id)?;

        // 更新提案状态
        let proposal = self.proposals.get_mut(proposal_id).unwrap();
        proposal.status = if result.passed {
            ProposalStatus::Passed
        } else {
            ProposalStatus::Rejected
        };

        Ok(result)
    }

    /// 取消提案
    pub fn cancel_proposal(&mut self, proposal_id: &str, canceller: &str) -> Result<(), String> {
        let proposal = self.proposals.get_mut(proposal_id)
            .ok_or_else(|| "Proposal not found".to_string())?;

        // 只有创建者可以取消
        if proposal.creator != canceller {
            return Err("Only creator can cancel the proposal".to_string());
        }

        // 只能取消草案或进行中的提案
        if !matches!(proposal.status, ProposalStatus::Draft | ProposalStatus::Active) {
            return Err(format!("Cannot cancel proposal in status: {:?}", proposal.status));
        }

        proposal.status = ProposalStatus::Cancelled;
        Ok(())
    }

    /// 获取提案
    pub fn get_proposal(&self, proposal_id: &str) -> Option<&Proposal> {
        self.proposals.get(proposal_id)
    }

    /// 获取所有提案
    pub fn get_all_proposals(&self) -> Vec<&Proposal> {
        self.proposals.values().collect()
    }

    /// 获取投票记录
    pub fn get_votes(&self, proposal_id: &str) -> Option<&Vec<VoteRecord>> {
        self.votes.get(proposal_id)
    }

    /// 获取账户的投票历史
    pub fn get_voter_history(&self, voter: &str) -> Vec<VoteRecord> {
        self.votes.values()
            .flatten()
            .filter(|v| v.voter == voter)
            .cloned()
            .collect()
    }

    /// 获取投票权信息
    pub fn get_voting_rights(&self, account: &str) -> Option<&VotingRights> {
        self.voting_rights.get(account)
    }

    /// 获取账户的代理授权
    pub fn get_proxy_authorizations(&self, principal: &str) -> Vec<&ProxyAuthorization> {
        self.proxy_authorizations.iter()
            .filter(|auth| auth.principal == principal && !auth.revoked)
            .collect()
    }

    /// 获取当前时间戳
    fn current_timestamp() -> u64 {
        std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_secs()
    }
}

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

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

    #[test]
    fn test_create_proposal() {
        let mut system = VotingSystem::new();
        let security_id = [1u8; 32];
        
        let current_time = VotingSystem::current_timestamp();
        let result = system.create_proposal(
            "Test Proposal".to_string(),
            "This is a test".to_string(),
            ProposalType::Other,
            "creator1".to_string(),
            security_id,
            current_time + 100,
            current_time + 1000,
            50,
            66,
        );

        assert!(result.is_ok());
        let proposal_id = result.unwrap();
        let proposal = system.get_proposal(&proposal_id).unwrap();
        assert_eq!(proposal.title, "Test Proposal");
        assert_eq!(proposal.status, ProposalStatus::Draft);
    }

    #[test]
    fn test_voting() {
        let mut system = VotingSystem::new();
        let security_id = [1u8; 32];
        
        // 设置投票权
        system.set_voting_rights("voter1".to_string(), 1000, 1);
        system.set_voting_rights("voter2".to_string(), 500, 2);

        // 创建提案
        let current_time = VotingSystem::current_timestamp();
        let proposal_id = system.create_proposal(
            "Test Proposal".to_string(),
            "Test".to_string(),
            ProposalType::Other,
            "creator1".to_string(),
            security_id,
            current_time,
            current_time + 1000,
            50,
            66,
        ).unwrap();

        // 激活提案
        system.activate_proposal(&proposal_id).unwrap();

        // 投票
        system.cast_vote(&proposal_id, "voter1", VoteOption::For, None).unwrap();
        system.cast_vote(&proposal_id, "voter2", VoteOption::Against, None).unwrap();

        // 检查投票记录
        let votes = system.get_votes(&proposal_id).unwrap();
        assert_eq!(votes.len(), 2);
        assert_eq!(votes[0].voting_power, 1000); // 1000 * 1
        assert_eq!(votes[1].voting_power, 1000); // 500 * 2
    }

    #[test]
    fn test_voting_result() {
        let mut system = VotingSystem::new();
        let security_id = [1u8; 32];
        
        system.set_voting_rights("voter1".to_string(), 1000, 1);
        system.set_voting_rights("voter2".to_string(), 500, 1);
        system.set_voting_rights("voter3".to_string(), 300, 1);

        let current_time = VotingSystem::current_timestamp();
        let proposal_id = system.create_proposal(
            "Test".to_string(),
            "Test".to_string(),
            ProposalType::Other,
            "creator1".to_string(),
            security_id,
            current_time,
            current_time + 1000,
            50,
            66,
        ).unwrap();

        system.activate_proposal(&proposal_id).unwrap();

        // 投票：1000赞成，500反对，300弃权
        system.cast_vote(&proposal_id, "voter1", VoteOption::For, None).unwrap();
        system.cast_vote(&proposal_id, "voter2", VoteOption::Against, None).unwrap();
        system.cast_vote(&proposal_id, "voter3", VoteOption::Abstain, None).unwrap();

        let result = system.calculate_result(&proposal_id).unwrap();
        
        assert_eq!(result.votes_for, 1000);
        assert_eq!(result.votes_against, 500);
        assert_eq!(result.votes_abstain, 300);
        assert_eq!(result.total_voting_power, 1800);
        assert_eq!(result.turnout_percentage, 100); // 1800/1800
        assert_eq!(result.approval_percentage, 66); // 1000/(1000+500)
        assert!(result.quorum_reached);
        assert!(result.passed);
    }

    #[test]
    fn test_proxy_voting() {
        let mut system = VotingSystem::new();
        let security_id = [1u8; 32];
        
        system.set_voting_rights("principal1".to_string(), 1000, 1);

        let current_time = VotingSystem::current_timestamp();
        let proposal_id = system.create_proposal(
            "Test".to_string(),
            "Test".to_string(),
            ProposalType::Other,
            "creator1".to_string(),
            security_id,
            current_time,
            current_time + 1000,
            50,
            50,
        ).unwrap();

        // 授权代理
        system.authorize_proxy(
            "principal1".to_string(),
            "proxy1".to_string(),
            Some(proposal_id.clone()),
            current_time,
            current_time + 2000,
        ).unwrap();

        system.activate_proposal(&proposal_id).unwrap();

        // 代理投票
        system.cast_vote(&proposal_id, "proxy1", VoteOption::For, Some("principal1")).unwrap();

        let votes = system.get_votes(&proposal_id).unwrap();
        assert_eq!(votes.len(), 1);
        assert_eq!(votes[0].voter, "principal1");
        assert!(votes[0].is_proxy);
        assert_eq!(votes[0].proxy.as_deref(), Some("proxy1"));
    }

    #[test]
    fn test_restrict_voting() {
        let mut system = VotingSystem::new();
        let security_id = [1u8; 32];
        
        system.set_voting_rights("voter1".to_string(), 1000, 1);

        let current_time = VotingSystem::current_timestamp();
        let proposal_id = system.create_proposal(
            "Test".to_string(),
            "Test".to_string(),
            ProposalType::Other,
            "creator1".to_string(),
            security_id,
            current_time,
            current_time + 1000,
            50,
            50,
        ).unwrap();

        system.activate_proposal(&proposal_id).unwrap();

        // 限制投票权
        system.restrict_voting("voter1", "Compliance issue".to_string()).unwrap();

        // 尝试投票应该失败
        let result = system.cast_vote(&proposal_id, "voter1", VoteOption::For, None);
        assert!(result.is_err());

        // 恢复投票权
        system.unrestrict_voting("voter1").unwrap();

        // 现在投票应该成功
        let result = system.cast_vote(&proposal_id, "voter1", VoteOption::For, None);
        assert!(result.is_ok());
    }
}