///! # 提案管理系统
///!
///! Proposal Management System
///! 提供提案创建、执行和历史管理功能
///!
///! **版本**: v1.0
///! **模块**: charter-std/governance/proposal.ch

use utils::math::{safe_add, safe_sub};
use utils::crypto::sha3_384_hash;

// ============================================================================
// 提案枚举
// ============================================================================

/// 提案类型
pub enum ProposalType {
    /// 参数修改
    ParameterChange,
    
    /// 资金支出
    Treasury,
    
    /// 合约升级
    Upgrade,
    
    /// 文本提案
    Text,
    
    /// 自定义
    Custom
}

/// 提案状态
pub enum ProposalStatus {
    /// 草稿
    Draft,
    
    /// 待投票
    Pending,
    
    /// 投票中
    Active,
    
    /// 已通过
    Passed,
    
    /// 未通过
    Rejected,
    
    /// 已执行
    Executed,
    
    /// 已取消
    Cancelled,
    
    /// 已过期
    Expired
}

// ============================================================================
// 提案结构
// ============================================================================

/// 提案
struct Proposal {
    /// 提案ID
    proposal_id: Hash,
    
    /// 提案类型
    proposal_type: ProposalType,
    
    /// 标题
    title: String,
    
    /// 描述
    description: String,
    
    /// 提案者
    proposer: Address,
    
    /// 创建时间
    created_at: Timestamp,
    
    /// 投票开始时间
    voting_start: Timestamp,
    
    /// 投票结束时间
    voting_end: Timestamp,
    
    /// 执行延迟（秒）
    execution_delay: Duration,
    
    /// 最早执行时间
    earliest_execution: Timestamp,
    
    /// 执行截止时间
    execution_deadline: Timestamp,
    
    /// 提案状态
    status: ProposalStatus,
    
    /// 投票ID
    vote_id: Option<Hash>,
    
    /// 执行交易哈希
    execution_tx: Option<Hash>,
    
    /// 执行时间
    executed_at: Option<Timestamp>,
    
    /// 取消原因
    cancellation_reason: Option<String>
}

/// 提案操作
struct ProposalAction {
    /// 目标合约
    target: Address,
    
    /// 函数签名
    function_sig: String,
    
    /// 调用数据
    call_data: Bytes,
    
    /// 转账金额
    value: u256,
    
    /// 描述
    description: String
}

/// 提案元数据
struct ProposalMetadata {
    /// 提案ID
    proposal_id: Hash,
    
    /// 标签
    tags: Vec<String>,
    
    /// 相关链接
    links: Vec<String>,
    
    /// 讨论链接
    discussion_url: Option<String>,
    
    /// 文档哈希
    document_hash: Option<Hash>
}

// ============================================================================
// 提案事件
// ============================================================================

/// 提案创建事件
event ProposalCreated {
    proposal_id: Hash,
    proposer: Address,
    title: String,
    proposal_type: ProposalType,
    timestamp: Timestamp
}

/// 提案提交事件
event ProposalSubmitted {
    proposal_id: Hash,
    vote_id: Hash,
    voting_start: Timestamp,
    voting_end: Timestamp,
    timestamp: Timestamp
}

/// 提案通过事件
event ProposalPassed {
    proposal_id: Hash,
    vote_id: Hash,
    timestamp: Timestamp
}

/// 提案拒绝事件
event ProposalRejected {
    proposal_id: Hash,
    vote_id: Hash,
    timestamp: Timestamp
}

/// 提案执行事件
event ProposalExecuted {
    proposal_id: Hash,
    executor: Address,
    execution_tx: Hash,
    timestamp: Timestamp
}

/// 提案取消事件
event ProposalCancelled {
    proposal_id: Hash,
    canceller: Address,
    reason: String,
    timestamp: Timestamp
}

// ============================================================================
// 提案管理系统
// ============================================================================

/// 提案管理系统
certificate ProposalManagement {
    /// 提案 (proposal_id => proposal)
    let _proposals: Map<Hash, Proposal>;
    
    /// 提案操作 (proposal_id => actions)
    let _proposal_actions: Map<Hash, Vec<ProposalAction>>;
    
    /// 提案元数据 (proposal_id => metadata)
    let _proposal_metadata: Map<Hash, ProposalMetadata>;
    
    /// 提案者提案列表 (proposer => proposal_ids)
    let _proposer_proposals: Map<Address, Vec<Hash>>;
    
    /// 投票系统地址
    let _voting_system: Address;
    
    /// 治理代币地址
    let _governance_token: Address;
    
    /// 时间锁地址
    let _timelock: Address;
    
    /// 管理员地址
    let _admin: Address;
    
    /// 提案门槛（需要的代币数量）
    let _proposal_threshold: u256;
    
    /// 默认投票期限（秒）
    let _default_voting_period: Duration;
    
    /// 默认执行延迟（秒）
    let _default_execution_delay: Duration;
    
    /// 执行窗口期（秒）
    let _execution_window: Duration;
    
    // ========== 构造函数 ==========
    
    constructor(
        voting_system: Address,
        governance_token: Address,
        timelock: Address,
        proposal_threshold: u256,
        voting_period: Duration,
        execution_delay: Duration,
        execution_window: Duration
    ) {
        require(!voting_system.is_zero(), "Invalid voting system");
        require(!governance_token.is_zero(), "Invalid governance token");
        require(!timelock.is_zero(), "Invalid timelock");
        require(proposal_threshold > 0, "Threshold must be positive");
        require(voting_period > 0, "Voting period must be positive");
        require(execution_delay > 0, "Execution delay must be positive");
        require(execution_window > 0, "Execution window must be positive");
        
        self._voting_system = voting_system;
        self._governance_token = governance_token;
        self._timelock = timelock;
        self._admin = msg.sender;
        self._proposal_threshold = proposal_threshold;
        self._default_voting_period = voting_period;
        self._default_execution_delay = execution_delay;
        self._execution_window = execution_window;
    }
    
    // ========== 提案创建 ==========
    
    /// 创建提案
    ///
    /// # 参数
    /// - `proposal_type`: 提案类型
    /// - `title`: 标题
    /// - `description`: 描述
    /// - `actions`: 操作列表
    ///
    /// # 返回
    /// - `Hash`: 提案ID
    pub fn create_proposal(
        proposal_type: ProposalType,
        title: String,
        description: String,
        actions: Vec<ProposalAction>
    ) -> Hash {
        require(!title.is_empty(), "Title required");
        require(!description.is_empty(), "Description required");
        
        // 检查提案门槛（实际需要查询治理代币余额）
        let proposer_balance = self._get_token_balance(msg.sender);
        require(
            proposer_balance >= self._proposal_threshold,
            "Insufficient tokens to propose"
        );
        
        // 生成提案ID
        let proposal_id = self._generate_proposal_id(msg.sender, title.clone());
        
        let proposal = Proposal {
            proposal_id: proposal_id,
            proposal_type: proposal_type,
            title: title.clone(),
            description: description,
            proposer: msg.sender,
            created_at: block.timestamp,
            voting_start: 0,
            voting_end: 0,
            execution_delay: self._default_execution_delay,
            earliest_execution: 0,
            execution_deadline: 0,
            status: ProposalStatus::Draft,
            vote_id: None,
            execution_tx: None,
            executed_at: None,
            cancellation_reason: None
        };
        
        self._proposals[proposal_id] = proposal;
        self._proposal_actions[proposal_id] = actions;
        
        // 添加到提案者列表
        if !self._proposer_proposals.contains_key(msg.sender) {
            self._proposer_proposals[msg.sender] = Vec::new();
        }
        self._proposer_proposals[msg.sender].push(proposal_id);
        
        emit ProposalCreated {
            proposal_id: proposal_id,
            proposer: msg.sender,
            title: title,
            proposal_type: proposal_type,
            timestamp: block.timestamp
        };
        
        return proposal_id;
    }
    
    /// 提交提案进行投票
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    /// - `voting_period`: 投票期限（秒，0表示使用默认值）
    ///
    /// # 返回
    /// - `Hash`: 投票ID
    pub fn submit_proposal(
        proposal_id: Hash,
        voting_period: Duration
    ) -> Hash {
        require(self._proposals.contains_key(proposal_id), "Proposal not found");
        
        let mut proposal = self._proposals[proposal_id];
        require(proposal.proposer == msg.sender, "Not the proposer");
        require(proposal.status == ProposalStatus::Draft, "Not in draft status");
        
        let period = if voting_period == 0 {
            self._default_voting_period
        } else {
            voting_period
        };
        
        let voting_start = block.timestamp;
        let voting_end = block.timestamp + period;
        
        // 创建投票（实际需要调用投票系统合约）
        let vote_id = self._create_vote(proposal_id, proposal.title.clone(), period);
        
        proposal.voting_start = voting_start;
        proposal.voting_end = voting_end;
        proposal.status = ProposalStatus::Active;
        proposal.vote_id = Some(vote_id);
        
        // 计算执行时间窗口
        proposal.earliest_execution = voting_end + proposal.execution_delay;
        proposal.execution_deadline = proposal.earliest_execution + self._execution_window;
        
        self._proposals[proposal_id] = proposal;
        
        emit ProposalSubmitted {
            proposal_id: proposal_id,
            vote_id: vote_id,
            voting_start: voting_start,
            voting_end: voting_end,
            timestamp: block.timestamp
        };
        
        return vote_id;
    }
    
    // ========== 提案执行 ==========
    
    /// 执行提案
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    ///
    /// # 返回
    /// - `bool`: 是否成功
    pub fn execute_proposal(proposal_id: Hash) -> bool {
        require(self._proposals.contains_key(proposal_id), "Proposal not found");
        
        let mut proposal = self._proposals[proposal_id];
        require(proposal.status == ProposalStatus::Passed, "Proposal not passed");
        require(
            block.timestamp >= proposal.earliest_execution,
            "Execution delay not met"
        );
        require(
            block.timestamp <= proposal.execution_deadline,
            "Execution deadline passed"
        );
        
        // 获取提案操作
        let actions = self._proposal_actions.get(proposal_id).unwrap_or(Vec::new());
        
        // 执行所有操作（实际需要通过时间锁执行）
        for action in actions {
            self._execute_action(action);
        }
        
        // 生成执行交易哈希
        let execution_tx = tx.hash;
        
        proposal.status = ProposalStatus::Executed;
        proposal.execution_tx = Some(execution_tx);
        proposal.executed_at = Some(block.timestamp);
        
        self._proposals[proposal_id] = proposal;
        
        emit ProposalExecuted {
            proposal_id: proposal_id,
            executor: msg.sender,
            execution_tx: execution_tx,
            timestamp: block.timestamp
        };
        
        return true;
    }
    
    /// 更新提案状态（根据投票结果）
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    ///
    /// # 返回
    /// - `bool`: 是否成功
    pub fn update_proposal_status(proposal_id: Hash) -> bool {
        require(self._proposals.contains_key(proposal_id), "Proposal not found");
        
        let mut proposal = self._proposals[proposal_id];
        require(proposal.status == ProposalStatus::Active, "Proposal not active");
        require(block.timestamp >= proposal.voting_end, "Voting not ended");
        
        // 获取投票结果（实际需要调用投票系统合约）
        let vote_result = self._get_vote_result(proposal.vote_id.unwrap());
        
        match vote_result {
            VoteResult::Passed => {
                proposal.status = ProposalStatus::Passed;
                
                emit ProposalPassed {
                    proposal_id: proposal_id,
                    vote_id: proposal.vote_id.unwrap(),
                    timestamp: block.timestamp
                };
            },
            _ => {
                proposal.status = ProposalStatus::Rejected;
                
                emit ProposalRejected {
                    proposal_id: proposal_id,
                    vote_id: proposal.vote_id.unwrap(),
                    timestamp: block.timestamp
                };
            }
        }
        
        self._proposals[proposal_id] = proposal;
        
        return true;
    }
    
    /// 取消提案
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    /// - `reason`: 取消原因
    ///
    /// # 返回
    /// - `bool`: 是否成功
    pub fn cancel_proposal(proposal_id: Hash, reason: String) -> bool {
        require(self._proposals.contains_key(proposal_id), "Proposal not found");
        
        let mut proposal = self._proposals[proposal_id];
        require(
            msg.sender == proposal.proposer || msg.sender == self._admin,
            "Not authorized"
        );
        require(
            proposal.status == ProposalStatus::Draft ||
            proposal.status == ProposalStatus::Pending ||
            proposal.status == ProposalStatus::Active,
            "Cannot cancel"
        );
        
        proposal.status = ProposalStatus::Cancelled;
        proposal.cancellation_reason = Some(reason.clone());
        
        self._proposals[proposal_id] = proposal;
        
        emit ProposalCancelled {
            proposal_id: proposal_id,
            canceller: msg.sender,
            reason: reason,
            timestamp: block.timestamp
        };
        
        return true;
    }
    
    // ========== 元数据管理 ==========
    
    /// 设置提案元数据
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    /// - `tags`: 标签
    /// - `links`: 相关链接
    /// - `discussion_url`: 讨论链接
    /// - `document_hash`: 文档哈希
    ///
    /// # 返回
    /// - `bool`: 是否成功
    pub fn set_proposal_metadata(
        proposal_id: Hash,
        tags: Vec<String>,
        links: Vec<String>,
        discussion_url: Option<String>,
        document_hash: Option<Hash>
    ) -> bool {
        require(self._proposals.contains_key(proposal_id), "Proposal not found");
        
        let proposal = self._proposals[proposal_id];
        require(proposal.proposer == msg.sender, "Not the proposer");
        
        let metadata = ProposalMetadata {
            proposal_id: proposal_id,
            tags: tags,
            links: links,
            discussion_url: discussion_url,
            document_hash: document_hash
        };
        
        self._proposal_metadata[proposal_id] = metadata;
        
        return true;
    }
    
    /// 获取提案元数据
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    ///
    /// # 返回
    /// - `Option<ProposalMetadata>`: 元数据
    pub fn get_proposal_metadata(proposal_id: Hash) -> Option<ProposalMetadata> {
        return self._proposal_metadata.get(proposal_id);
    }
    
    // ========== 查询函数 ==========
    
    /// 获取提案
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    ///
    /// # 返回
    /// - `Proposal`: 提案信息
    pub fn get_proposal(proposal_id: Hash) -> Proposal {
        require(self._proposals.contains_key(proposal_id), "Proposal not found");
        return self._proposals[proposal_id];
    }
    
    /// 获取提案操作
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    ///
    /// # 返回
    /// - `Vec<ProposalAction>`: 操作列表
    pub fn get_proposal_actions(proposal_id: Hash) -> Vec<ProposalAction> {
        return self._proposal_actions.get(proposal_id).unwrap_or(Vec::new());
    }
    
    /// 获取提案者的提案列表
    ///
    /// # 参数
    /// - `proposer`: 提案者地址
    ///
    /// # 返回
    /// - `Vec<Hash>`: 提案ID列表
    pub fn get_proposer_proposals(proposer: Address) -> Vec<Hash> {
        return self._proposer_proposals.get(proposer).unwrap_or(Vec::new());
    }
    
    /// 检查提案是否可执行
    ///
    /// # 参数
    /// - `proposal_id`: 提案ID
    ///
    /// # 返回
    /// - `bool`: 是否可执行
    pub fn is_executable(proposal_id: Hash) -> bool {
        if !self._proposals.contains_key(proposal_id) {
            return false;
        }
        
        let proposal = self._proposals[proposal_id];
        
        return proposal.status == ProposalStatus::Passed &&
               block.timestamp >= proposal.earliest_execution &&
               block.timestamp <= proposal.execution_deadline;
    }
    
    // ========== 内部函数 ==========
    
    /// 生成提案ID
    fn _generate_proposal_id(proposer: Address, title: String) -> Hash {
        let mut data = Bytes::new();
        data.extend(proposer.as_bytes());
        data.extend(title.as_bytes());
        data.extend(block.timestamp.to_bytes());
        data.extend(tx.hash.as_bytes());
        return sha3_384_hash(data);
    }
    
    /// 获取代币余额（简化，实际需要调用代币合约）
    fn _get_token_balance(account: Address) -> u256 {
        return 1000; // 简化
    }
    
    /// 创建投票（简化，实际需要调用投票系统合约）
    fn _create_vote(proposal_id: Hash, title: String, period: Duration) -> Hash {
        // 实际需要调用投票系统的create_vote函数
        return sha3_384_hash(proposal_id.as_bytes());
    }
    
    /// 获取投票结果（简化，实际需要调用投票系统合约）
    fn _get_vote_result(vote_id: Hash) -> VoteResult {
        // 实际需要调用投票系统的get_vote_result函数
        return VoteResult::Passed;
    }
    
    /// 执行操作（简化，实际需要通过时间锁执行）
    fn _execute_action(action: ProposalAction) {
        // 实际需要通过时间锁合约执行
        // timelock.execute(action.target, action.function_sig, action.call_data, action.value)
    }
    
    // ========== 管理函数 ==========
    
    /// 设置提案门槛
    pub fn set_proposal_threshold(threshold: u256) -> bool {
        require(msg.sender == self._admin, "Only admin");
        require(threshold > 0, "Threshold must be positive");
        self._proposal_threshold = threshold;
        return true;
    }
    
    /// 设置默认投票期限
    pub fn set_default_voting_period(period: Duration) -> bool {
        require(msg.sender == self._admin, "Only admin");
        require(period > 0, "Period must be positive");
        self._default_voting_period = period;
        return true;
    }
    
    /// 设置默认执行延迟
    pub fn set_default_execution_delay(delay: Duration) -> bool {
        require(msg.sender == self._admin, "Only admin");
        require(delay > 0, "Delay must be positive");
        self._default_execution_delay = delay;
        return true;
    }
}

// ============================================================================
// 投票结果枚举（从voting.ch引用）
// ============================================================================

enum VoteResult {
    Undecided,
    Passed,
    Failed,
    QuorumNotReached
}