/// Query Handler Helpers
/// 
/// Extracted to reduce query_handler complexity.

use actix_web::HttpResponse;
use serde::Serialize;
use serde_json::json;
use std::collections::HashMap;

use crate::query_worker::QueryResult;

// ============================================================================
// Query Parameters
// ============================================================================

/// Search method for query endpoint
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum SearchMethod {
    Semantic,
    #[default]
    Hybrid,
}

impl SearchMethod {
    pub fn from_str(s: &str) -> Self {
        match s {
            "semantic" => Self::Semantic,
            _ => Self::Hybrid,
        }
    }
    
    pub fn as_str(&self) -> &'static str {
        match self {
            Self::Semantic => "semantic",
            Self::Hybrid => "hybrid",
        }
    }
}

/// Validated query parameters
#[derive(Debug, Clone)]
pub struct QueryParams {
    pub project: String,
    pub question: String,
    pub limit: i64,
    pub method: SearchMethod,
}

impl QueryParams {
    /// Parse and validate query parameters
    pub fn from_query(query: &HashMap<String, String>) -> Result<Self, QueryParamsError> {
        let project = query.get("project")
            .filter(|p| !p.is_empty())
            .ok_or(QueryParamsError::MissingProject)?
            .clone();
        
        let question = query.get("query")
            .filter(|q| !q.is_empty())
            .ok_or(QueryParamsError::MissingQuery)?
            .clone();
        
        let limit = query.get("limit")
            .and_then(|l| l.parse::<i64>().ok())
            .unwrap_or(10)
            .clamp(1, 100);
        
        let method = query.get("method")
            .map(|m| SearchMethod::from_str(m))
            .unwrap_or_default();
        
        Ok(Self { project, question, limit, method })
    }
}

/// Query parameter validation errors
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum QueryParamsError {
    MissingProject,
    MissingQuery,
}

impl QueryParamsError {
    pub fn to_response(&self) -> HttpResponse {
        let reason = match self {
            Self::MissingProject => "missing project parameter",
            Self::MissingQuery => "missing query parameter",
        };
        HttpResponse::BadRequest().json(json!({"error": reason}))
    }
}

// ============================================================================
// Search Response Builder
// ============================================================================

#[derive(Debug, Clone, Serialize)]
pub struct SearchResultItem {
    pub level: String,
    pub score: f32,
    pub text: String,
    pub source: Option<String>,
    pub provenance: Vec<String>,
}

impl From<QueryResult> for SearchResultItem {
    fn from(r: QueryResult) -> Self {
        Self {
            level: r.level,
            score: r.score,
            text: r.text,
            source: r.source,
            provenance: r.provenance,
        }
    }
}

/// Build search response JSON
pub fn build_search_response(
    params: &QueryParams,
    results: Vec<QueryResult>,
    method_override: Option<&str>,
) -> HttpResponse {
    let items: Vec<SearchResultItem> = results
        .into_iter()
        .take(params.limit as usize)
        .map(SearchResultItem::from)
        .collect();
    
    HttpResponse::Ok().json(json!({
        "query": params.question,
        "project": params.project,
        "method": method_override.unwrap_or(params.method.as_str()),
        "results": items
    }))
}

// ============================================================================
// Tests
// ============================================================================

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

    fn make_query(pairs: &[(&str, &str)]) -> HashMap<String, String> {
        pairs.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect()
    }

    #[test]
    fn test_query_params_valid() {
        let query = make_query(&[("project", "homelab"), ("query", "kubernetes")]);
        let params = QueryParams::from_query(&query).unwrap();
        
        assert_eq!(params.project, "homelab");
        assert_eq!(params.question, "kubernetes");
        assert_eq!(params.limit, 10);
        assert_eq!(params.method, SearchMethod::Hybrid);
    }

    #[test]
    fn test_query_params_with_limit() {
        let query = make_query(&[("project", "test"), ("query", "foo"), ("limit", "25")]);
        let params = QueryParams::from_query(&query).unwrap();
        assert_eq!(params.limit, 25);
    }

    #[test]
    fn test_query_params_limit_clamped_max() {
        let query = make_query(&[("project", "test"), ("query", "foo"), ("limit", "999")]);
        let params = QueryParams::from_query(&query).unwrap();
        assert_eq!(params.limit, 100);
    }

    #[test]
    fn test_query_params_limit_clamped_min() {
        let query = make_query(&[("project", "test"), ("query", "foo"), ("limit", "0")]);
        let params = QueryParams::from_query(&query).unwrap();
        assert_eq!(params.limit, 1);
    }

    #[test]
    fn test_query_params_semantic_method() {
        let query = make_query(&[("project", "test"), ("query", "foo"), ("method", "semantic")]);
        let params = QueryParams::from_query(&query).unwrap();
        assert_eq!(params.method, SearchMethod::Semantic);
    }

    #[test]
    fn test_query_params_missing_project() {
        let query = make_query(&[("query", "foo")]);
        assert_eq!(QueryParams::from_query(&query).unwrap_err(), QueryParamsError::MissingProject);
    }

    #[test]
    fn test_query_params_empty_project() {
        let query = make_query(&[("project", ""), ("query", "foo")]);
        assert_eq!(QueryParams::from_query(&query).unwrap_err(), QueryParamsError::MissingProject);
    }

    #[test]
    fn test_query_params_missing_query() {
        let query = make_query(&[("project", "homelab")]);
        assert_eq!(QueryParams::from_query(&query).unwrap_err(), QueryParamsError::MissingQuery);
    }

    #[test]
    fn test_query_params_empty_query() {
        let query = make_query(&[("project", "homelab"), ("query", "")]);
        assert_eq!(QueryParams::from_query(&query).unwrap_err(), QueryParamsError::MissingQuery);
    }

    #[test]
    fn test_search_method_from_str() {
        assert_eq!(SearchMethod::from_str("semantic"), SearchMethod::Semantic);
        assert_eq!(SearchMethod::from_str("hybrid"), SearchMethod::Hybrid);
        assert_eq!(SearchMethod::from_str("unknown"), SearchMethod::Hybrid);
    }
}