//! 反馈信号收集与信任度管理（Phase 5 反馈闭环）
//! 收集用户对进化产物（技能/Pipeline）的显式/隐式反馈
//! 管理信任度衰减和优化循环
//! 信任度记录通过 VikingAdapter 持久化

use std::collections::HashMap;
use std::sync::Arc;

use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};

use crate::types::MemoryType;
use crate::viking_adapter::VikingAdapter;

/// 反馈信号类型
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum FeedbackSignal {
    /// 用户直接表达的意见
    Explicit,
    /// 从使用行为推断
    ImplicitUsage,
    /// 使用频率
    UsageCount,
    /// 任务完成率
    CompletionRate,
}

/// 情感倾向
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum Sentiment {
    Positive,
    Negative,
    Neutral,
}

/// 进化产物类型
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub enum EvolutionArtifact {
    Skill,
    Pipeline,
}

/// 单条反馈记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FeedbackEntry {
    pub artifact_id: String,
    pub artifact_type: EvolutionArtifact,
    pub signal: FeedbackSignal,
    pub sentiment: Sentiment,
    pub details: Option<String>,
    pub timestamp: DateTime<Utc>,
}

/// 信任度记录
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TrustRecord {
    pub artifact_id: String,
    pub artifact_type: EvolutionArtifact,
    pub trust_score: f32,
    pub total_feedback: u32,
    pub positive_count: u32,
    pub negative_count: u32,
    pub last_updated: DateTime<Utc>,
}

/// 反馈收集器
/// 管理反馈记录和信任度评分
/// 通过 VikingAdapter 持久化信任度记录（可选）
pub struct FeedbackCollector {
    trust_records: HashMap<String, TrustRecord>,
    viking: Option<Arc<VikingAdapter>>,
}

impl FeedbackCollector {
    pub fn new() -> Self {
        Self {
            trust_records: HashMap::new(),
            viking: None,
        }
    }

    /// 创建带 VikingAdapter 的 FeedbackCollector
    pub fn with_viking(viking: Arc<VikingAdapter>) -> Self {
        Self {
            trust_records: HashMap::new(),
            viking: Some(viking),
        }
    }

    /// 从 VikingAdapter 加载已持久化的信任度记录
    pub async fn load(&mut self) -> Result<usize, String> {
        let viking = match &self.viking {
            Some(v) => v,
            None => return Ok(0),
        };

        // MemoryEntry::new("feedback", Session, artifact_id) 生成
        // URI: agent://feedback/sessions/{artifact_id}
        let entries = viking
            .find_by_prefix("agent://feedback/sessions/")
            .await
            .map_err(|e| format!("Failed to load trust records: {}", e))?;

        let mut count = 0;
        for entry in entries {
            match serde_json::from_str::<TrustRecord>(&entry.content) {
                Ok(record) => {
                    self.trust_records
                        .insert(record.artifact_id.clone(), record);
                    count += 1;
                }
                Err(e) => {
                    tracing::warn!(
                        "[FeedbackCollector] Failed to deserialize trust record at {}: {}",
                        entry.uri,
                        e
                    );
                }
            }
        }

        tracing::debug!(
            "[FeedbackCollector] Loaded {} trust records from storage",
            count
        );
        Ok(count)
    }

    /// 将信任度记录持久化到 VikingAdapter
    pub async fn save(&self) -> Result<usize, String> {
        let viking = match &self.viking {
            Some(v) => v,
            None => return Ok(0),
        };

        let mut saved = 0;
        for record in self.trust_records.values() {
            let content =
                serde_json::to_string(record).unwrap_or_default();
            let entry = crate::types::MemoryEntry::new(
                "feedback",
                MemoryType::Session,
                &record.artifact_id,
                content,
            )
            .with_importance((record.trust_score * 10.0) as u8);

            match viking.store(&entry).await {
                Ok(_) => saved += 1,
                Err(e) => {
                    tracing::warn!(
                        "[FeedbackCollector] Failed to save trust record {}: {}",
                        record.artifact_id,
                        e
                    );
                }
            }
        }

        tracing::debug!(
            "[FeedbackCollector] Saved {} trust records to storage",
            saved
        );
        Ok(saved)
    }

    /// 提交一条反馈
    pub fn submit_feedback(&mut self, entry: FeedbackEntry) -> TrustUpdate {
        let record = self
            .trust_records
            .entry(entry.artifact_id.clone())
            .or_insert_with(|| TrustRecord {
                artifact_id: entry.artifact_id.clone(),
                artifact_type: entry.artifact_type.clone(),
                trust_score: 0.5,
                total_feedback: 0,
                positive_count: 0,
                negative_count: 0,
                last_updated: Utc::now(),
            });

        // 更新计数
        record.total_feedback += 1;
        match entry.sentiment {
            Sentiment::Positive => record.positive_count += 1,
            Sentiment::Negative => record.negative_count += 1,
            Sentiment::Neutral => {}
        }

        // 重新计算信任度
        let old_score = record.trust_score;
        record.trust_score = Self::calculate_trust_internal(
            record.positive_count,
            record.negative_count,
            record.total_feedback,
            record.last_updated,
        );
        record.last_updated = Utc::now();

        let new_score = record.trust_score;
        let total = record.total_feedback;
        let action = Self::recommend_action_internal(new_score, total);

        TrustUpdate {
            artifact_id: entry.artifact_id.clone(),
            old_score,
            new_score,
            action,
        }
    }

    /// 获取信任度记录
    pub fn get_trust(&self, artifact_id: &str) -> Option<&TrustRecord> {
        self.trust_records.get(artifact_id)
    }

    /// 获取所有需要优化的产物（信任度 < 0.4）
    pub fn get_artifacts_needing_optimization(&self) -> Vec<&TrustRecord> {
        self.trust_records
            .values()
            .filter(|r| r.trust_score < 0.4 && r.total_feedback >= 2)
            .collect()
    }

    /// 获取所有应该归档的产物（信任度 < 0.2 且反馈 >= 5）
    pub fn get_artifacts_to_archive(&self) -> Vec<&TrustRecord> {
        self.trust_records
            .values()
            .filter(|r| r.trust_score < 0.2 && r.total_feedback >= 5)
            .collect()
    }

    /// 获取所有高信任产物（信任度 >= 0.8）
    pub fn get_recommended_artifacts(&self) -> Vec<&TrustRecord> {
        self.trust_records
            .values()
            .filter(|r| r.trust_score >= 0.8)
            .collect()
    }

    fn calculate_trust_internal(
        positive: u32,
        negative: u32,
        total: u32,
        last_updated: DateTime<Utc>,
    ) -> f32 {
        if total == 0 {
            return 0.5;
        }
        let positive_ratio = positive as f32 / total as f32;
        let negative_penalty = negative as f32 * 0.1;
        let days_since = (Utc::now() - last_updated).num_days().max(0) as f32;
        let time_decay = 1.0 - (days_since * 0.005).min(0.5);
        (positive_ratio * time_decay - negative_penalty).clamp(0.0, 1.0)
    }

    fn recommend_action_internal(trust_score: f32, total_feedback: u32) -> RecommendedAction {
        if trust_score >= 0.8 {
            RecommendedAction::Promote
        } else if trust_score < 0.2 && total_feedback >= 5 {
            RecommendedAction::Archive
        } else if trust_score < 0.4 && total_feedback >= 2 {
            RecommendedAction::Optimize
        } else {
            RecommendedAction::Monitor
        }
    }
}

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

/// 信任度更新结果
#[derive(Debug, Clone)]
pub struct TrustUpdate {
    pub artifact_id: String,
    pub old_score: f32,
    pub new_score: f32,
    pub action: RecommendedAction,
}

/// 建议动作
#[derive(Debug, Clone, PartialEq)]
pub enum RecommendedAction {
    /// 继续观察
    Monitor,
    /// 需要优化
    Optimize,
    /// 建议归档（降级为记忆）
    Archive,
    /// 建议提升为推荐技能
    Promote,
}

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

    fn make_feedback(artifact_id: &str, sentiment: Sentiment) -> FeedbackEntry {
        FeedbackEntry {
            artifact_id: artifact_id.to_string(),
            artifact_type: EvolutionArtifact::Skill,
            signal: FeedbackSignal::Explicit,
            sentiment,
            details: None,
            timestamp: Utc::now(),
        }
    }

    #[test]
    fn test_initial_trust() {
        let collector = FeedbackCollector::new();
        assert!(collector.get_trust("skill-1").is_none());
    }

    #[test]
    fn test_positive_feedback_increases_trust() {
        let mut collector = FeedbackCollector::new();
        collector.submit_feedback(make_feedback("skill-1", Sentiment::Positive));
        let record = collector.get_trust("skill-1").unwrap();
        assert!(record.trust_score > 0.5);
        assert_eq!(record.positive_count, 1);
    }

    #[test]
    fn test_negative_feedback_decreases_trust() {
        let mut collector = FeedbackCollector::new();
        collector.submit_feedback(make_feedback("skill-1", Sentiment::Negative));
        let record = collector.get_trust("skill-1").unwrap();
        assert!(record.trust_score < 0.5);
    }

    #[test]
    fn test_mixed_feedback() {
        let mut collector = FeedbackCollector::new();
        collector.submit_feedback(make_feedback("skill-1", Sentiment::Positive));
        collector.submit_feedback(make_feedback("skill-1", Sentiment::Positive));
        collector.submit_feedback(make_feedback("skill-1", Sentiment::Negative));
        let record = collector.get_trust("skill-1").unwrap();
        assert_eq!(record.total_feedback, 3);
        assert!(record.trust_score > 0.3); // 2/3 positive
    }

    #[test]
    fn test_recommend_optimize() {
        let mut collector = FeedbackCollector::new();
        collector.submit_feedback(make_feedback("skill-1", Sentiment::Negative));
        let update = collector.submit_feedback(make_feedback("skill-1", Sentiment::Negative));
        assert_eq!(update.action, RecommendedAction::Optimize);
    }

    #[test]
    fn test_needs_optimization_filter() {
        let mut collector = FeedbackCollector::new();
        collector.submit_feedback(make_feedback("bad-skill", Sentiment::Negative));
        collector.submit_feedback(make_feedback("bad-skill", Sentiment::Negative));
        collector.submit_feedback(make_feedback("good-skill", Sentiment::Positive));

        let needs = collector.get_artifacts_needing_optimization();
        assert_eq!(needs.len(), 1);
        assert_eq!(needs[0].artifact_id, "bad-skill");
    }

    #[test]
    fn test_promote_recommendation() {
        let mut collector = FeedbackCollector::new();
        for _ in 0..5 {
            collector.submit_feedback(make_feedback("great-skill", Sentiment::Positive));
        }
        let recommended = collector.get_recommended_artifacts();
        assert_eq!(recommended.len(), 1);
    }

    #[tokio::test]
    async fn test_save_and_load_roundtrip() {
        let viking = Arc::new(crate::VikingAdapter::in_memory());

        // 写入阶段
        let mut collector = FeedbackCollector::with_viking(viking.clone());
        collector.submit_feedback(make_feedback("skill-a", Sentiment::Positive));
        collector.submit_feedback(make_feedback("skill-a", Sentiment::Positive));
        collector.submit_feedback(make_feedback("skill-b", Sentiment::Negative));

        let saved = collector.save().await.unwrap();
        assert_eq!(saved, 2); // 2 个 artifact

        // 读取阶段：新 collector 从存储加载
        let mut collector2 = FeedbackCollector::with_viking(viking);
        let loaded = collector2.load().await.unwrap();
        assert_eq!(loaded, 2);

        let record_a = collector2.get_trust("skill-a").unwrap();
        assert_eq!(record_a.positive_count, 2);
        assert_eq!(record_a.total_feedback, 2);

        let record_b = collector2.get_trust("skill-b").unwrap();
        assert_eq!(record_b.negative_count, 1);
    }

    #[tokio::test]
    async fn test_load_without_viking_returns_zero() {
        let mut collector = FeedbackCollector::new();
        let loaded = collector.load().await.unwrap();
        assert_eq!(loaded, 0);
    }

    #[tokio::test]
    async fn test_save_without_viking_returns_zero() {
        let collector = FeedbackCollector::new();
        let saved = collector.save().await.unwrap();
        assert_eq!(saved, 0);
    }
}