//! User Profile Store — structured user modeling from conversation patterns.
//!
//! Maintains a single `UserProfile` per user (desktop uses "default_user")
//! in a dedicated SQLite table. Vec fields (recent_topics, pain points,
//! preferred_tools) are stored as JSON arrays and transparently
//! (de)serialised on read/write.

use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use sqlx::Row;
use sqlx::SqlitePool;
use zclaw_types::Result;

// ---------------------------------------------------------------------------
// Data types
// ---------------------------------------------------------------------------

/// Expertise level inferred from conversation patterns.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum Level {
    Beginner,
    Intermediate,
    Expert,
}

impl Level {
    pub fn as_str(&self) -> &'static str {
        match self {
            Level::Beginner => "beginner",
            Level::Intermediate => "intermediate",
            Level::Expert => "expert",
        }
    }

    pub fn from_str_lossy(s: &str) -> Option<Self> {
        match s {
            "beginner" => Some(Level::Beginner),
            "intermediate" => Some(Level::Intermediate),
            "expert" => Some(Level::Expert),
            _ => None,
        }
    }
}

/// Communication style preference.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum CommStyle {
    Concise,
    Detailed,
    Formal,
    Casual,
}

impl CommStyle {
    pub fn as_str(&self) -> &'static str {
        match self {
            CommStyle::Concise => "concise",
            CommStyle::Detailed => "detailed",
            CommStyle::Formal => "formal",
            CommStyle::Casual => "casual",
        }
    }

    pub fn from_str_lossy(s: &str) -> Option<Self> {
        match s {
            "concise" => Some(CommStyle::Concise),
            "detailed" => Some(CommStyle::Detailed),
            "formal" => Some(CommStyle::Formal),
            "casual" => Some(CommStyle::Casual),
            _ => None,
        }
    }
}

/// Structured user profile (one record per user).
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UserProfile {
    pub user_id: String,
    pub industry: Option<String>,
    pub role: Option<String>,
    pub expertise_level: Option<Level>,
    pub communication_style: Option<CommStyle>,
    pub preferred_language: String,
    pub recent_topics: Vec<String>,
    pub active_pain_points: Vec<String>,
    pub preferred_tools: Vec<String>,
    pub confidence: f32,
    pub updated_at: DateTime<Utc>,
}

impl UserProfile {
    /// Create a blank profile for the given user.
    pub fn blank(user_id: &str) -> Self {
        Self {
            user_id: user_id.to_string(),
            industry: None,
            role: None,
            expertise_level: None,
            communication_style: None,
            preferred_language: "zh-CN".to_string(),
            recent_topics: Vec::new(),
            active_pain_points: Vec::new(),
            preferred_tools: Vec::new(),
            confidence: 0.0,
            updated_at: Utc::now(),
        }
    }

    /// Default profile for single-user desktop mode ("default_user").
    pub fn default_profile() -> Self {
        Self::blank("default_user")
    }
}

// ---------------------------------------------------------------------------
// DDL
// ---------------------------------------------------------------------------

const PROFILE_DDL: &str = r#"
CREATE TABLE IF NOT EXISTS user_profiles (
    user_id           TEXT PRIMARY KEY,
    industry          TEXT,
    role              TEXT,
    expertise_level   TEXT,
    communication_style TEXT,
    preferred_language TEXT DEFAULT 'zh-CN',
    recent_topics     TEXT DEFAULT '[]',
    active_pain_points TEXT DEFAULT '[]',
    preferred_tools   TEXT DEFAULT '[]',
    confidence        REAL DEFAULT 0.0,
    updated_at        TEXT NOT NULL
)
"#;

// ---------------------------------------------------------------------------
// Row mapping
// ---------------------------------------------------------------------------

fn row_to_profile(row: &sqlx::sqlite::SqliteRow) -> Result<UserProfile> {
    let recent_topics_json: String = row.try_get("recent_topics").unwrap_or_else(|_| "[]".to_string());
    let pain_json: String = row.try_get("active_pain_points").unwrap_or_else(|_| "[]".to_string());
    let tools_json: String = row.try_get("preferred_tools").unwrap_or_else(|_| "[]".to_string());

    let recent_topics: Vec<String> = serde_json::from_str(&recent_topics_json)?;
    let active_pain_points: Vec<String> = serde_json::from_str(&pain_json)?;
    let preferred_tools: Vec<String> = serde_json::from_str(&tools_json)?;

    let expertise_str: Option<String> = row.try_get("expertise_level").unwrap_or(None);
    let comm_str: Option<String> = row.try_get("communication_style").unwrap_or(None);

    let updated_at_str: String = row.try_get("updated_at").unwrap_or_else(|_| Utc::now().to_rfc3339());
    let updated_at = DateTime::parse_from_rfc3339(&updated_at_str)
        .map(|dt| dt.with_timezone(&Utc))
        .unwrap_or_else(|_| Utc::now());

    Ok(UserProfile {
        user_id: row.try_get("user_id").unwrap_or_default(),
        industry: row.try_get("industry").unwrap_or(None),
        role: row.try_get("role").unwrap_or(None),
        expertise_level: expertise_str.as_deref().and_then(Level::from_str_lossy),
        communication_style: comm_str.as_deref().and_then(CommStyle::from_str_lossy),
        preferred_language: row.try_get("preferred_language").unwrap_or_else(|_| "zh-CN".to_string()),
        recent_topics,
        active_pain_points,
        preferred_tools,
        confidence: row.try_get("confidence").unwrap_or(0.0),
        updated_at,
    })
}

// ---------------------------------------------------------------------------
// UserProfileStore
// ---------------------------------------------------------------------------

/// SQLite-backed store for user profiles.
pub struct UserProfileStore {
    pool: SqlitePool,
}

impl UserProfileStore {
    /// Create a new store backed by the given connection pool.
    pub fn new(pool: SqlitePool) -> Self {
        Self { pool }
    }

    /// Create tables. Idempotent — safe to call on every startup.
    pub async fn initialize_schema(&self) -> Result<()> {
        sqlx::query(PROFILE_DDL)
            .execute(&self.pool)
            .await
            .map_err(|e| zclaw_types::ZclawError::StorageError(e.to_string()))?;
        Ok(())
    }

    /// Fetch the profile for a user. Returns `None` when no row exists.
    pub async fn get(&self, user_id: &str) -> Result<Option<UserProfile>> {
        let row = sqlx::query(
            "SELECT user_id, industry, role, expertise_level, communication_style, \
                    preferred_language, recent_topics, active_pain_points, preferred_tools, \
                    confidence, updated_at \
             FROM user_profiles WHERE user_id = ?",
        )
        .bind(user_id)
        .fetch_optional(&self.pool)
        .await
        .map_err(|e| zclaw_types::ZclawError::StorageError(e.to_string()))?;

        match row {
            Some(r) => Ok(Some(row_to_profile(&r)?)),
            None => Ok(None),
        }
    }

    /// Insert or replace the full profile.
    pub async fn upsert(&self, profile: &UserProfile) -> Result<()> {
        let topics = serde_json::to_string(&profile.recent_topics)?;
        let pains = serde_json::to_string(&profile.active_pain_points)?;
        let tools = serde_json::to_string(&profile.preferred_tools)?;
        let expertise = profile.expertise_level.map(|l| l.as_str());
        let comm = profile.communication_style.map(|c| c.as_str());
        let updated = profile.updated_at.to_rfc3339();

        sqlx::query(
            "INSERT OR REPLACE INTO user_profiles \
                (user_id, industry, role, expertise_level, communication_style, \
                 preferred_language, recent_topics, active_pain_points, preferred_tools, \
                 confidence, updated_at) \
             VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
        )
        .bind(&profile.user_id)
        .bind(&profile.industry)
        .bind(&profile.role)
        .bind(expertise)
        .bind(comm)
        .bind(&profile.preferred_language)
        .bind(&topics)
        .bind(&pains)
        .bind(&tools)
        .bind(profile.confidence)
        .bind(&updated)
        .execute(&self.pool)
        .await
        .map_err(|e| zclaw_types::ZclawError::StorageError(e.to_string()))?;

        Ok(())
    }

    /// Update a single scalar field by name.
    ///
    /// `field` must be one of: industry, role, expertise_level,
    /// communication_style, preferred_language, confidence.
    /// Returns error for unrecognised field names (prevents SQL injection).
    pub async fn update_field(&self, user_id: &str, field: &str, value: &str) -> Result<()> {
        let sql = match field {
            "industry" => "UPDATE user_profiles SET industry = ?, updated_at = ? WHERE user_id = ?",
            "role" => "UPDATE user_profiles SET role = ?, updated_at = ? WHERE user_id = ?",
            "expertise_level" => {
                "UPDATE user_profiles SET expertise_level = ?, updated_at = ? WHERE user_id = ?"
            }
            "communication_style" => {
                "UPDATE user_profiles SET communication_style = ?, updated_at = ? WHERE user_id = ?"
            }
            "preferred_language" => {
                "UPDATE user_profiles SET preferred_language = ?, updated_at = ? WHERE user_id = ?"
            }
            "confidence" => {
                "UPDATE user_profiles SET confidence = ?, updated_at = ? WHERE user_id = ?"
            }
            _ => {
                return Err(zclaw_types::ZclawError::InvalidInput(format!(
                    "Unknown profile field: {}",
                    field
                )));
            }
        };

        let now = Utc::now().to_rfc3339();

        // confidence is REAL; parse the value string.
        if field == "confidence" {
            let f: f32 = value.parse().map_err(|_| {
                zclaw_types::ZclawError::InvalidInput(format!("Invalid confidence: {}", value))
            })?;
            sqlx::query(sql)
                .bind(f)
                .bind(&now)
                .bind(user_id)
                .execute(&self.pool)
                .await
                .map_err(|e| zclaw_types::ZclawError::StorageError(e.to_string()))?;
        } else {
            sqlx::query(sql)
                .bind(value)
                .bind(&now)
                .bind(user_id)
                .execute(&self.pool)
                .await
                .map_err(|e| zclaw_types::ZclawError::StorageError(e.to_string()))?;
        }

        Ok(())
    }

    /// Append a topic to `recent_topics`, trimming to `max_topics`.
    /// Creates a default profile row if none exists.
    pub async fn add_recent_topic(
        &self,
        user_id: &str,
        topic: &str,
        max_topics: usize,
    ) -> Result<()> {
        let mut profile = self
            .get(user_id)
            .await?
            .unwrap_or_else(|| UserProfile::blank(user_id));

        // Deduplicate: remove if already present, then push to front.
        profile.recent_topics.retain(|t| t != topic);
        profile.recent_topics.insert(0, topic.to_string());
        profile.recent_topics.truncate(max_topics);
        profile.updated_at = Utc::now();

        self.upsert(&profile).await
    }

    /// Append a pain point, trimming to `max_pains`.
    /// Creates a default profile row if none exists.
    pub async fn add_pain_point(
        &self,
        user_id: &str,
        pain: &str,
        max_pains: usize,
    ) -> Result<()> {
        let mut profile = self
            .get(user_id)
            .await?
            .unwrap_or_else(|| UserProfile::blank(user_id));

        profile.active_pain_points.retain(|p| p != pain);
        profile.active_pain_points.insert(0, pain.to_string());
        profile.active_pain_points.truncate(max_pains);
        profile.updated_at = Utc::now();

        self.upsert(&profile).await
    }

    /// Append a preferred tool, trimming to `max_tools`.
    /// Creates a default profile row if none exists.
    pub async fn add_preferred_tool(
        &self,
        user_id: &str,
        tool: &str,
        max_tools: usize,
    ) -> Result<()> {
        let mut profile = self
            .get(user_id)
            .await?
            .unwrap_or_else(|| UserProfile::blank(user_id));

        profile.preferred_tools.retain(|t| t != tool);
        profile.preferred_tools.insert(0, tool.to_string());
        profile.preferred_tools.truncate(max_tools);
        profile.updated_at = Utc::now();

        self.upsert(&profile).await
    }
}

// ---------------------------------------------------------------------------
// Tests
// ---------------------------------------------------------------------------

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

    /// Helper: create an in-memory store with schema.
    async fn test_store() -> UserProfileStore {
        let pool = SqlitePool::connect("sqlite::memory:")
            .await
            .expect("in-memory pool");
        let store = UserProfileStore::new(pool);
        store.initialize_schema().await.expect("schema init");
        store
    }

    #[tokio::test]
    async fn test_initialize_schema_idempotent() {
        let store = test_store().await;
        // Second call should succeed without error.
        store.initialize_schema().await.unwrap();
        store.initialize_schema().await.unwrap();
    }

    #[tokio::test]
    async fn test_get_returns_none_for_missing() {
        let store = test_store().await;
        let profile = store.get("nonexistent").await.unwrap();
        assert!(profile.is_none());
    }

    #[tokio::test]
    async fn test_upsert_and_get() {
        let store = test_store().await;
        let mut profile = UserProfile::blank("default_user");
        profile.industry = Some("healthcare".to_string());
        profile.role = Some("admin".to_string());
        profile.expertise_level = Some(Level::Intermediate);
        profile.communication_style = Some(CommStyle::Concise);
        profile.recent_topics = vec!["reporting".to_string(), "compliance".to_string()];
        profile.confidence = 0.65;

        store.upsert(&profile).await.unwrap();

        let loaded = store.get("default_user").await.unwrap().unwrap();
        assert_eq!(loaded.user_id, "default_user");
        assert_eq!(loaded.industry.as_deref(), Some("healthcare"));
        assert_eq!(loaded.role.as_deref(), Some("admin"));
        assert_eq!(loaded.expertise_level, Some(Level::Intermediate));
        assert_eq!(loaded.communication_style, Some(CommStyle::Concise));
        assert_eq!(loaded.recent_topics, vec!["reporting", "compliance"]);
        assert!((loaded.confidence - 0.65).abs() < f32::EPSILON);
    }

    #[tokio::test]
    async fn test_upsert_replaces_existing() {
        let store = test_store().await;
        let mut profile = UserProfile::blank("user1");
        profile.industry = Some("tech".to_string());
        store.upsert(&profile).await.unwrap();

        profile.industry = Some("finance".to_string());
        store.upsert(&profile).await.unwrap();

        let loaded = store.get("user1").await.unwrap().unwrap();
        assert_eq!(loaded.industry.as_deref(), Some("finance"));
    }

    #[tokio::test]
    async fn test_update_field_scalar() {
        let store = test_store().await;
        let profile = UserProfile::blank("user2");
        store.upsert(&profile).await.unwrap();

        store
            .update_field("user2", "industry", "education")
            .await
            .unwrap();
        store
            .update_field("user2", "role", "teacher")
            .await
            .unwrap();

        let loaded = store.get("user2").await.unwrap().unwrap();
        assert_eq!(loaded.industry.as_deref(), Some("education"));
        assert_eq!(loaded.role.as_deref(), Some("teacher"));
    }

    #[tokio::test]
    async fn test_update_field_confidence() {
        let store = test_store().await;
        let profile = UserProfile::blank("user3");
        store.upsert(&profile).await.unwrap();

        store
            .update_field("user3", "confidence", "0.88")
            .await
            .unwrap();

        let loaded = store.get("user3").await.unwrap().unwrap();
        assert!((loaded.confidence - 0.88).abs() < f32::EPSILON);
    }

    #[tokio::test]
    async fn test_update_field_rejects_unknown() {
        let store = test_store().await;
        let result = store.update_field("user", "evil_column", "oops").await;
        assert!(result.is_err());
    }

    #[tokio::test]
    async fn test_add_recent_topic_auto_creates_profile() {
        let store = test_store().await;

        // No profile exists yet.
        store
            .add_recent_topic("new_user", "data analysis", 5)
            .await
            .unwrap();

        let loaded = store.get("new_user").await.unwrap().unwrap();
        assert_eq!(loaded.recent_topics, vec!["data analysis"]);
    }

    #[tokio::test]
    async fn test_add_recent_topic_dedup_and_trim() {
        let store = test_store().await;
        let profile = UserProfile::blank("user");
        store.upsert(&profile).await.unwrap();

        store.add_recent_topic("user", "topic_a", 3).await.unwrap();
        store.add_recent_topic("user", "topic_b", 3).await.unwrap();
        store.add_recent_topic("user", "topic_c", 3).await.unwrap();
        // Duplicate — should move to front, not add.
        store.add_recent_topic("user", "topic_a", 3).await.unwrap();

        let loaded = store.get("user").await.unwrap().unwrap();
        assert_eq!(
            loaded.recent_topics,
            vec!["topic_a", "topic_c", "topic_b"]
        );
    }

    #[tokio::test]
    async fn test_add_pain_point_trim() {
        let store = test_store().await;

        for i in 0..5 {
            store
                .add_pain_point("user", &format!("pain_{}", i), 3)
                .await
                .unwrap();
        }

        let loaded = store.get("user").await.unwrap().unwrap();
        assert_eq!(loaded.active_pain_points.len(), 3);
        // Most recent first.
        assert_eq!(loaded.active_pain_points[0], "pain_4");
    }

    #[tokio::test]
    async fn test_add_preferred_tool_trim() {
        let store = test_store().await;

        store
            .add_preferred_tool("user", "python", 5)
            .await
            .unwrap();
        store
            .add_preferred_tool("user", "rust", 5)
            .await
            .unwrap();
        // Duplicate — moved to front.
        store
            .add_preferred_tool("user", "python", 5)
            .await
            .unwrap();

        let loaded = store.get("user").await.unwrap().unwrap();
        assert_eq!(loaded.preferred_tools, vec!["python", "rust"]);
    }

    #[test]
    fn test_level_round_trip() {
        for level in [Level::Beginner, Level::Intermediate, Level::Expert] {
            assert_eq!(Level::from_str_lossy(level.as_str()), Some(level));
        }
        assert_eq!(Level::from_str_lossy("unknown"), None);
    }

    #[test]
    fn test_comm_style_round_trip() {
        for style in [
            CommStyle::Concise,
            CommStyle::Detailed,
            CommStyle::Formal,
            CommStyle::Casual,
        ] {
            assert_eq!(CommStyle::from_str_lossy(style.as_str()), Some(style));
        }
        assert_eq!(CommStyle::from_str_lossy("unknown"), None);
    }

    #[test]
    fn test_profile_serialization() {
        let mut p = UserProfile::blank("test_user");
        p.industry = Some("logistics".into());
        p.expertise_level = Some(Level::Expert);
        p.communication_style = Some(CommStyle::Detailed);
        p.recent_topics = vec!["exports".into(), "customs".into()];

        let json = serde_json::to_string(&p).unwrap();
        let decoded: UserProfile = serde_json::from_str(&json).unwrap();
        assert_eq!(decoded.user_id, "test_user");
        assert_eq!(decoded.industry.as_deref(), Some("logistics"));
        assert_eq!(decoded.expertise_level, Some(Level::Expert));
        assert_eq!(decoded.communication_style, Some(CommStyle::Detailed));
        assert_eq!(decoded.recent_topics, vec!["exports", "customs"]);
    }
}