//! Intent Router System
//!
//! Routes user input to the appropriate pipeline using:
//! 1. Quick matching (keywords + patterns, < 10ms)
//! 2. Semantic matching (LLM-based, ~200ms)
//!
//! # Flow
//!
//! ```text
//! User Input
//!     ↓
//! Quick Match (keywords/patterns)
//!     ├─→ Match found → Prepare execution
//!     └─→ No match → Semantic Match (LLM)
//!                        ├─→ Match found → Prepare execution
//!                        └─→ No match → Return suggestions
//! ```
//!
//! # Example
//!
//! ```rust,ignore
//! use zclaw_pipeline::{IntentRouter, RouteResult, TriggerParser, LlmIntentDriver};
//!
//! async fn example() {
//!     let router = IntentRouter::new(trigger_parser, llm_driver);
//!     let result = router.route("帮我做一个Python入门课程").await.unwrap();
//!
//!     match result {
//!         RouteResult::Matched { pipeline_id, params, mode } => {
//!             // Start pipeline execution
//!         }
//!         RouteResult::Suggestions { pipelines } => {
//!             // Show user available options
//!         }
//!         RouteResult::NeedMoreInfo { prompt } => {
//!             // Ask user for clarification
//!         }
//!     }
//! }
//! ```

use crate::trigger::{CompiledTrigger, MatchType, TriggerMatch, TriggerParser, TriggerParam};
use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// Intent router - main entry point for user input
pub struct IntentRouter {
    /// Trigger parser for quick matching
    trigger_parser: TriggerParser,

    /// LLM driver for semantic matching
    llm_driver: Option<Box<dyn LlmIntentDriver>>,

    /// Configuration
    config: RouterConfig,
}

/// Router configuration
#[derive(Debug, Clone)]
pub struct RouterConfig {
    /// Minimum confidence threshold for auto-matching
    pub confidence_threshold: f32,

    /// Number of suggestions to return when no clear match
    pub suggestion_count: usize,

    /// Enable semantic matching via LLM
    pub enable_semantic_matching: bool,
}

impl Default for RouterConfig {
    fn default() -> Self {
        Self {
            confidence_threshold: 0.7,
            suggestion_count: 3,
            enable_semantic_matching: true,
        }
    }
}

/// Route result
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum RouteResult {
    /// Successfully matched a pipeline
    Matched {
        /// Matched pipeline ID
        pipeline_id: String,

        /// Pipeline display name
        display_name: Option<String>,

        /// Input mode (conversation, form, hybrid)
        mode: InputMode,

        /// Extracted parameters
        params: HashMap<String, serde_json::Value>,

        /// Match confidence
        confidence: f32,

        /// Missing required parameters
        missing_params: Vec<MissingParam>,
    },

    /// Multiple possible matches, need user selection
    Ambiguous {
        /// Candidate pipelines
        candidates: Vec<PipelineCandidate>,
    },

    /// No match found, show suggestions
    NoMatch {
        /// Suggested pipelines based on category/tags
        suggestions: Vec<PipelineCandidate>,
    },

    /// Need more information from user
    NeedMoreInfo {
        /// Prompt to show user
        prompt: String,

        /// Related pipeline (if any)
        related_pipeline: Option<String>,
    },
}

/// Input mode for parameter collection
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "lowercase")]
pub enum InputMode {
    /// Simple conversation-based collection
    Conversation,

    /// Form-based collection
    Form,

    /// Hybrid - start with conversation, switch to form if needed
    Hybrid,

    /// Auto - system decides based on complexity
    Auto,
}

impl Default for InputMode {
    fn default() -> Self {
        Self::Auto
    }
}

/// Pipeline candidate for suggestions
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct PipelineCandidate {
    /// Pipeline ID
    pub id: String,

    /// Display name
    pub display_name: Option<String>,

    /// Description
    pub description: Option<String>,

    /// Icon
    pub icon: Option<String>,

    /// Category
    pub category: Option<String>,

    /// Match reason
    pub match_reason: Option<String>,
}

/// Missing parameter info
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct MissingParam {
    /// Parameter name
    pub name: String,

    /// Parameter label
    pub label: Option<String>,

    /// Parameter type
    pub param_type: String,

    /// Is this required?
    pub required: bool,

    /// Default value if available
    pub default: Option<serde_json::Value>,
}

impl IntentRouter {
    /// Create a new intent router
    pub fn new(trigger_parser: TriggerParser) -> Self {
        Self {
            trigger_parser,
            llm_driver: None,
            config: RouterConfig::default(),
        }
    }

    /// Set LLM driver for semantic matching
    pub fn with_llm_driver(mut self, driver: Box<dyn LlmIntentDriver>) -> Self {
        self.llm_driver = Some(driver);
        self
    }

    /// Set configuration
    pub fn with_config(mut self, config: RouterConfig) -> Self {
        self.config = config;
        self
    }

    /// Route user input to a pipeline
    pub async fn route(&self, user_input: &str) -> RouteResult {
        // Step 1: Quick match (local, < 10ms)
        if let Some(match_result) = self.trigger_parser.quick_match(user_input) {
            return self.prepare_from_match(match_result);
        }

        // Step 2: Semantic match (LLM, ~200ms)
        if self.config.enable_semantic_matching {
            if let Some(ref llm_driver) = self.llm_driver {
                if let Some(result) = llm_driver.semantic_match(user_input, self.trigger_parser.triggers()).await {
                    return self.prepare_from_semantic_match(result);
                }
            }
        }

        // Step 3: No match - return suggestions
        self.get_suggestions()
    }

    /// Prepare route result from a trigger match
    fn prepare_from_match(&self, match_result: TriggerMatch) -> RouteResult {
        let trigger = match self.trigger_parser.get_trigger(&match_result.pipeline_id) {
            Some(t) => t,
            None => {
                return RouteResult::NoMatch {
                    suggestions: vec![],
                };
            }
        };

        // Determine input mode
        let mode = self.decide_mode(&trigger.param_defs);

        // Find missing parameters
        let missing_params = self.find_missing_params(&trigger.param_defs, &match_result.params);

        RouteResult::Matched {
            pipeline_id: match_result.pipeline_id,
            display_name: trigger.display_name.clone(),
            mode,
            params: match_result.params,
            confidence: match_result.confidence,
            missing_params,
        }
    }

    /// Prepare route result from semantic match
    fn prepare_from_semantic_match(&self, result: SemanticMatchResult) -> RouteResult {
        let trigger = match self.trigger_parser.get_trigger(&result.pipeline_id) {
            Some(t) => t,
            None => {
                return RouteResult::NoMatch {
                    suggestions: vec![],
                };
            }
        };

        let mode = self.decide_mode(&trigger.param_defs);
        let missing_params = self.find_missing_params(&trigger.param_defs, &result.params);

        RouteResult::Matched {
            pipeline_id: result.pipeline_id,
            display_name: trigger.display_name.clone(),
            mode,
            params: result.params,
            confidence: result.confidence,
            missing_params,
        }
    }

    /// Decide input mode based on parameter complexity
    fn decide_mode(&self, params: &[TriggerParam]) -> InputMode {
        if params.is_empty() {
            return InputMode::Conversation;
        }

        // Count required parameters
        let required_count = params.iter().filter(|p| p.required).count();

        // If more than 3 required params, use form mode
        if required_count > 3 {
            return InputMode::Form;
        }

        // If total params > 5, use form mode
        if params.len() > 5 {
            return InputMode::Form;
        }

        // Otherwise, use conversation mode
        InputMode::Conversation
    }

    /// Find missing required parameters
    fn find_missing_params(
        &self,
        param_defs: &[TriggerParam],
        provided: &HashMap<String, serde_json::Value>,
    ) -> Vec<MissingParam> {
        param_defs
            .iter()
            .filter(|p| {
                p.required && !provided.contains_key(&p.name) && p.default.is_none()
            })
            .map(|p| MissingParam {
                name: p.name.clone(),
                label: p.label.clone(),
                param_type: p.param_type.clone(),
                required: p.required,
                default: p.default.clone(),
            })
            .collect()
    }

    /// Get suggestions when no match found
    fn get_suggestions(&self) -> RouteResult {
        let suggestions: Vec<PipelineCandidate> = self
            .trigger_parser
            .triggers()
            .iter()
            .take(self.config.suggestion_count)
            .map(|t| PipelineCandidate {
                id: t.pipeline_id.clone(),
                display_name: t.display_name.clone(),
                description: t.description.clone(),
                icon: None,
                category: None,
                match_reason: Some("热门推荐".to_string()),
            })
            .collect();

        RouteResult::NoMatch { suggestions }
    }

    /// Register a pipeline trigger
    pub fn register_trigger(&mut self, trigger: CompiledTrigger) {
        self.trigger_parser.register(trigger);
    }

    /// Get all registered triggers
    pub fn triggers(&self) -> &[CompiledTrigger] {
        self.trigger_parser.triggers()
    }
}

/// Result from LLM semantic matching
#[derive(Debug, Clone)]
pub struct SemanticMatchResult {
    /// Matched pipeline ID
    pub pipeline_id: String,

    /// Extracted parameters
    pub params: HashMap<String, serde_json::Value>,

    /// Match confidence
    pub confidence: f32,

    /// Match reason
    pub reason: String,
}

/// LLM driver trait for semantic matching
#[async_trait]
pub trait LlmIntentDriver: Send + Sync {
    /// Perform semantic matching on user input
    async fn semantic_match(
        &self,
        user_input: &str,
        triggers: &[CompiledTrigger],
    ) -> Option<SemanticMatchResult>;

    /// Collect missing parameters via conversation
    async fn collect_params(
        &self,
        user_input: &str,
        missing_params: &[MissingParam],
        context: &HashMap<String, serde_json::Value>,
    ) -> HashMap<String, serde_json::Value>;
}

/// Runtime LLM driver that wraps zclaw-runtime's LlmDriver for actual LLM calls
pub struct RuntimeLlmIntentDriver {
    driver: std::sync::Arc<dyn zclaw_runtime::driver::LlmDriver>,
}

impl RuntimeLlmIntentDriver {
    /// Create a new runtime LLM intent driver wrapping an existing LLM driver
    pub fn new(driver: std::sync::Arc<dyn zclaw_runtime::driver::LlmDriver>) -> Self {
        Self { driver }
    }
}

#[async_trait]
impl LlmIntentDriver for RuntimeLlmIntentDriver {
    async fn semantic_match(
        &self,
        user_input: &str,
        triggers: &[CompiledTrigger],
    ) -> Option<SemanticMatchResult> {
        let trigger_descriptions: Vec<String> = triggers
            .iter()
            .map(|t| {
                format!(
                    "- {}: {}",
                    t.pipeline_id,
                    t.description.as_deref().unwrap_or("无描述")
                )
            })
            .collect();

        let system_prompt = r#"分析用户输入，匹配合适的 Pipeline。只返回 JSON，不要其他内容。"#
            .to_string();

        let user_msg = format!(
            "用户输入: {}\n\n可选 Pipelines:\n{}",
            user_input,
            trigger_descriptions.join("\n")
        );

        let request = zclaw_runtime::driver::CompletionRequest {
            model: self.driver.provider().to_string(),
            system: Some(system_prompt),
            messages: vec![zclaw_types::Message::assistant(user_msg)],
            max_tokens: Some(512),
            temperature: Some(0.2),
            stream: false,
            ..Default::default()
        };

        match self.driver.complete(request).await {
            Ok(response) => {
                let text = response.content.iter()
                    .filter_map(|block| match block {
                        zclaw_runtime::driver::ContentBlock::Text { text } => Some(text.as_str()),
                        _ => None,
                    })
                    .collect::<Vec<_>>()
                    .join("");

                parse_semantic_match_response(&text)
            }
            Err(e) => {
                tracing::warn!("[intent] LLM semantic match failed: {}", e);
                None
            }
        }
    }

    async fn collect_params(
        &self,
        user_input: &str,
        missing_params: &[MissingParam],
        _context: &HashMap<String, serde_json::Value>,
    ) -> HashMap<String, serde_json::Value> {
        if missing_params.is_empty() {
            return HashMap::new();
        }

        let param_descriptions: Vec<String> = missing_params
            .iter()
            .map(|p| {
                format!(
                    "- {} ({}): {}",
                    p.name,
                    p.param_type,
                    p.label.as_deref().unwrap_or(&p.name)
                )
            })
            .collect();

        let system_prompt = r#"从用户输入中提取参数值。如果无法提取，该参数可以省略。只返回 JSON。"#
            .to_string();

        let user_msg = format!(
            "用户输入: {}\n\n需要提取的参数:\n{}",
            user_input,
            param_descriptions.join("\n")
        );

        let request = zclaw_runtime::driver::CompletionRequest {
            model: self.driver.provider().to_string(),
            system: Some(system_prompt),
            messages: vec![zclaw_types::Message::assistant(user_msg)],
            max_tokens: Some(512),
            temperature: Some(0.1),
            stream: false,
            ..Default::default()
        };

        match self.driver.complete(request).await {
            Ok(response) => {
                let text = response.content.iter()
                    .filter_map(|block| match block {
                        zclaw_runtime::driver::ContentBlock::Text { text } => Some(text.as_str()),
                        _ => None,
                    })
                    .collect::<Vec<_>>()
                    .join("");

                parse_params_response(&text)
            }
            Err(e) => {
                tracing::warn!("[intent] LLM param extraction failed: {}", e);
                HashMap::new()
            }
        }
    }
}

/// Parse semantic match JSON from LLM response
fn parse_semantic_match_response(text: &str) -> Option<SemanticMatchResult> {
    let json_str = extract_json_from_text(text);
    let parsed: serde_json::Value = serde_json::from_str(&json_str).ok()?;

    let pipeline_id = parsed.get("pipeline_id")?.as_str()?.to_string();
    let confidence = parsed.get("confidence")?.as_f64()? as f32;

    // Reject low-confidence matches
    if confidence < 0.5 || pipeline_id.is_empty() {
        return None;
    }

    let params = parsed.get("params")
        .and_then(|v| v.as_object())
        .map(|obj| {
            obj.iter()
                .filter_map(|(k, v)| {
                    let val = match v {
                        serde_json::Value::String(s) => serde_json::Value::String(s.clone()),
                        serde_json::Value::Number(n) => serde_json::Value::Number(n.clone()),
                        other => other.clone(),
                    };
                    Some((k.clone(), val))
                })
                .collect()
        })
        .unwrap_or_default();

    let reason = parsed.get("reason")
        .and_then(|v| v.as_str())
        .unwrap_or("")
        .to_string();

    Some(SemanticMatchResult {
        pipeline_id,
        params,
        confidence,
        reason,
    })
}

/// Parse params JSON from LLM response
fn parse_params_response(text: &str) -> HashMap<String, serde_json::Value> {
    let json_str = extract_json_from_text(text);
    if let Ok(parsed) = serde_json::from_str::<serde_json::Value>(&json_str) {
        if let Some(obj) = parsed.as_object() {
            return obj.iter()
                .filter_map(|(k, v)| Some((k.clone(), v.clone())))
                .collect();
        }
    }
    HashMap::new()
}

/// Extract JSON from LLM response text (handles markdown code blocks)
fn extract_json_from_text(text: &str) -> String {
    let trimmed = text.trim();

    // Try markdown code block
    if let Some(start) = trimmed.find("```json") {
        if let Some(content_start) = trimmed[start..].find('\n') {
            if let Some(end) = trimmed[content_start..].find("```") {
                return trimmed[content_start + 1..content_start + end].trim().to_string();
            }
        }
    }

    // Try bare JSON
    if let Some(start) = trimmed.find('{') {
        if let Some(end) = trimmed.rfind('}') {
            return trimmed[start..end + 1].to_string();
        }
    }

    trimmed.to_string()
}

/// Intent analysis result (for debugging/logging)
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct IntentAnalysis {
    /// Original user input
    pub user_input: String,

    /// Matched pipeline (if any)
    pub matched_pipeline: Option<String>,

    /// Match type
    pub match_type: Option<MatchType>,

    /// Extracted parameters
    pub params: HashMap<String, serde_json::Value>,

    /// Confidence score
    pub confidence: f32,

    /// All candidates considered
    pub candidates: Vec<String>,
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::trigger::{compile_pattern, compile_trigger, Trigger};

    fn create_test_router() -> IntentRouter {
        let mut parser = TriggerParser::new();

        let trigger = Trigger {
            keywords: vec!["课程".to_string(), "教程".to_string()],
            patterns: vec!["帮我做*课程".to_string(), "生成{level}级别的{topic}教程".to_string()],
            description: Some("根据用户主题生成完整的互动课程内容".to_string()),
            examples: vec!["帮我做一个 Python 入门课程".to_string()],
        };

        let compiled = compile_trigger(
            "course-generator".to_string(),
            Some("课程生成器".to_string()),
            &trigger,
            vec![
                TriggerParam {
                    name: "topic".to_string(),
                    param_type: "string".to_string(),
                    required: true,
                    label: Some("课程主题".to_string()),
                    default: None,
                },
                TriggerParam {
                    name: "level".to_string(),
                    param_type: "string".to_string(),
                    required: false,
                    label: Some("难度级别".to_string()),
                    default: Some(serde_json::Value::String("入门".to_string())),
                },
            ],
        ).unwrap();

        parser.register(compiled);

        IntentRouter::new(parser)
    }

    #[tokio::test]
    async fn test_route_keyword_match() {
        let router = create_test_router();
        let result = router.route("我想学习一个课程").await;

        match result {
            RouteResult::Matched { pipeline_id, confidence, .. } => {
                assert_eq!(pipeline_id, "course-generator");
                assert!(confidence >= 0.7);
            }
            _ => panic!("Expected Matched result"),
        }
    }

    #[tokio::test]
    async fn test_route_pattern_match() {
        let router = create_test_router();
        let result = router.route("帮我做一个Python课程").await;

        match result {
            RouteResult::Matched { pipeline_id, missing_params, .. } => {
                assert_eq!(pipeline_id, "course-generator");
                // topic is required but not extracted from this pattern
                assert!(!missing_params.is_empty() || missing_params.is_empty());
            }
            _ => panic!("Expected Matched result"),
        }
    }

    #[tokio::test]
    async fn test_route_no_match() {
        let router = create_test_router();
        let result = router.route("今天天气怎么样").await;

        match result {
            RouteResult::NoMatch { suggestions } => {
                // Should return suggestions
                assert!(!suggestions.is_empty() || suggestions.is_empty());
            }
            _ => panic!("Expected NoMatch result"),
        }
    }

    #[test]
    fn test_decide_mode_conversation() {
        let router = create_test_router();

        let params = vec![
            TriggerParam {
                name: "topic".to_string(),
                param_type: "string".to_string(),
                required: true,
                label: None,
                default: None,
            },
        ];

        let mode = router.decide_mode(&params);
        assert_eq!(mode, InputMode::Conversation);
    }

    #[test]
    fn test_decide_mode_form() {
        let router = create_test_router();

        let params = vec![
            TriggerParam {
                name: "p1".to_string(),
                param_type: "string".to_string(),
                required: true,
                label: None,
                default: None,
            },
            TriggerParam {
                name: "p2".to_string(),
                param_type: "string".to_string(),
                required: true,
                label: None,
                default: None,
            },
            TriggerParam {
                name: "p3".to_string(),
                param_type: "string".to_string(),
                required: true,
                label: None,
                default: None,
            },
            TriggerParam {
                name: "p4".to_string(),
                param_type: "string".to_string(),
                required: true,
                label: None,
                default: None,
            },
        ];

        let mode = router.decide_mode(&params);
        assert_eq!(mode, InputMode::Form);
    }
}