use std::sync::Arc;

use mistralai_client::v1::{
    chat::{ChatMessage, ChatParams, ResponseFormat},
    constants::Model,
};
use opensearch::OpenSearch;
use serde::Deserialize;
use tracing::{debug, warn};

use crate::config::Config;
use crate::context::ResponseContext;
use crate::brain::responder::chat_blocking;

use super::store;

#[derive(Debug, Deserialize)]
pub(crate) struct ExtractionResponse {
    pub memories: Vec<ExtractedMemory>,
}

#[derive(Debug, Deserialize)]
pub(crate) struct ExtractedMemory {
    pub content: String,
    pub category: String,
}

/// Validate and normalize a category string.
pub(crate) fn normalize_category(raw: &str) -> &str {
    match raw {
        "preference" | "fact" | "context" => raw,
        _ => "general",
    }
}

pub async fn extract_and_store(
    mistral: &Arc<mistralai_client::v1::client::Client>,
    opensearch: &OpenSearch,
    config: &Config,
    ctx: &ResponseContext,
    user_message: &str,
    sol_response: &str,
) -> anyhow::Result<()> {
    let display = ctx
        .display_name
        .as_deref()
        .unwrap_or(&ctx.matrix_user_id);

    let prompt = format!(
        "Analyze this conversation exchange and extract any facts worth remembering about {display}.\n\
         Focus on: preferences, personal details, ongoing projects, opinions, recurring topics.\n\n\
         They said: {user_message}\n\
         Response: {sol_response}\n\n\
         Respond ONLY with JSON: {{\"memories\": [{{\"content\": \"...\", \"category\": \"preference|fact|context\"}}]}}\n\
         If nothing worth remembering, respond with {{\"memories\": []}}.\n\
         Be selective — only genuinely useful information."
    );

    let messages = vec![ChatMessage::new_user_message(&prompt)];
    let model = Model::new(&config.mistral.evaluation_model);
    let params = ChatParams {
        response_format: Some(ResponseFormat::json_object()),
        ..Default::default()
    };

    let response = chat_blocking(mistral, model, messages, params).await?;
    let text = response.choices[0].message.content.text();
    let text = text.trim();

    let extraction: ExtractionResponse = match serde_json::from_str(text) {
        Ok(e) => e,
        Err(e) => {
            debug!(raw = text, "Failed to parse extraction response: {e}");
            return Ok(());
        }
    };

    if extraction.memories.is_empty() {
        debug!("No memories extracted");
        return Ok(());
    }

    let index = &config.opensearch.memory_index;
    for mem in &extraction.memories {
        let category = normalize_category(&mem.category);

        if let Err(e) = store::set(
            opensearch,
            index,
            &ctx.user_id,
            &mem.content,
            category,
            "auto",
        )
        .await
        {
            warn!("Failed to store extracted memory: {e}");
        }
    }

    debug!(
        count = extraction.memories.len(),
        user = ctx.user_id.as_str(),
        "Extracted and stored memories"
    );

    Ok(())
}

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

    #[test]
    fn test_parse_extraction_response_with_memories() {
        let json = r#"{"memories": [
            {"content": "prefers terse answers", "category": "preference"},
            {"content": "working on drive UI", "category": "fact"}
        ]}"#;
        let resp: ExtractionResponse = serde_json::from_str(json).unwrap();
        assert_eq!(resp.memories.len(), 2);
        assert_eq!(resp.memories[0].content, "prefers terse answers");
        assert_eq!(resp.memories[0].category, "preference");
        assert_eq!(resp.memories[1].category, "fact");
    }

    #[test]
    fn test_parse_extraction_response_empty() {
        let json = r#"{"memories": []}"#;
        let resp: ExtractionResponse = serde_json::from_str(json).unwrap();
        assert!(resp.memories.is_empty());
    }

    #[test]
    fn test_parse_extraction_response_invalid_json() {
        let json = "not json at all";
        assert!(serde_json::from_str::<ExtractionResponse>(json).is_err());
    }

    #[test]
    fn test_parse_extraction_response_missing_field() {
        let json = r#"{"memories": [{"content": "hi"}]}"#;
        assert!(serde_json::from_str::<ExtractionResponse>(json).is_err());
    }

    #[test]
    fn test_normalize_category_valid() {
        assert_eq!(normalize_category("preference"), "preference");
        assert_eq!(normalize_category("fact"), "fact");
        assert_eq!(normalize_category("context"), "context");
    }

    #[test]
    fn test_normalize_category_unknown_falls_back() {
        assert_eq!(normalize_category("opinion"), "general");
        assert_eq!(normalize_category(""), "general");
        assert_eq!(normalize_category("PREFERENCE"), "general");
    }
}