use actix_web::{web, App, HttpServer, HttpResponse, HttpRequest, middleware::Logger};
use anyhow::Result;
use mem_llm::{EmbeddingsClient, RerankClient};
use mem_store::{init_schema, VectorStore};
use serde_json::json;
use sqlx::PgPool;
use std::sync::Arc;
use std::time::Instant;
use crate::endpoints::IngestRequest;
use crate::ingest_worker::IngestWorker;
use crate::query_worker::QueryWorker;

/// Server state with database and workers
pub struct AppState {
    pub api_key: String,
    pub start_time: Instant,
    pub pool: PgPool,
    pub vector_store: Arc<VectorStore>,
    pub embeddings: Arc<EmbeddingsClient>,
    pub ingest_worker: Arc<IngestWorker>,
    pub query_worker: Arc<QueryWorker>,
}

/// Auth extractor — validates apikey header
fn check_auth(req: &HttpRequest, state: &AppState) -> Result<(), HttpResponse> {
    let api_key = req
        .headers()
        .get("apikey")
        .and_then(|h| h.to_str().ok())
        .map(|s| s.to_string());

    if api_key.as_ref() != Some(&state.api_key) {
        return Err(HttpResponse::Unauthorized().json(json!({"error": "unauthorized", "reason": "missing apikey header"})));
    }
    Ok(())
}

/// Start HTTP server with database initialization
pub async fn start_server(port: u16, api_key: String, database_url: &str) -> Result<()> {
    // Create connection pool
    let pool = PgPool::connect(database_url).await?;
    tracing::info!("Connected to database");

    // Initialize schema
    init_schema(&pool).await?;
    tracing::info!("Schema initialized");

    // Create workers
    let vector_store = Arc::new(VectorStore::new(pool.clone()));
    let embeddings = Arc::new(EmbeddingsClient::from_env()?);
    let ingest_worker = Arc::new(IngestWorker::new(pool.clone(), (*embeddings).clone()));
    let reranker = RerankClient::from_env()?;
    let query_worker = Arc::new(QueryWorker::new(VectorStore::new(pool.clone()), (*embeddings).clone(), reranker));

    let state = web::Data::new(AppState {
        api_key,
        start_time: Instant::now(),
        pool,
        vector_store,
        embeddings,
        ingest_worker,
        query_worker,
    });

    tracing::info!("Starting HTTP server on port {}", port);

    HttpServer::new(move || {
        App::new()
            .app_data(state.clone())
            .wrap(Logger::default())
            .route("/health", web::get().to(health_check))
            .route("/memory/ingest", web::post().to(ingest_handler))
            .route("/memory/ingest/{ingest_id}", web::get().to(ingest_status))
            .route("/memory/query", web::get().to(query_handler))
            .route("/memory/projects", web::get().to(projects_handler))
            .route("/memory/skills", web::get().to(skills_handler))
    })
    .bind(("0.0.0.0", port))?
    .run()
    .await?;

    Ok(())
}

/// Health check (no auth)
pub async fn health_check(state: web::Data<AppState>) -> HttpResponse {
    let uptime = state.start_time.elapsed().as_secs();
    HttpResponse::Ok().json(json!({"status": "ok", "uptime_seconds": uptime}))
}

/// POST /memory/ingest — queue an ingest job
pub async fn ingest_handler(
    req: HttpRequest,
    body: web::Json<IngestRequest>,
    state: web::Data<AppState>,
) -> HttpResponse {
    if let Err(e) = check_auth(&req, &state) {
        return e;
    }

    let project = body.project.clone();
    let ingest_id = body.ingest_id.clone();
    let records: Vec<(String, String)> = body
        .records
        .iter()
        .map(|r| (r.text.clone(), body.source.clone()))
        .collect();

    // Create ingest job in DB
    let job_result = sqlx::query(
        "INSERT INTO ingest_jobs (id, project, ingest_id, status, created_at)
         VALUES ($1, $2, $3, 'pending', NOW())
         ON CONFLICT (ingest_id) DO NOTHING
         RETURNING id",
    )
    .bind(uuid::Uuid::new_v4())
    .bind(&project)
    .bind(&ingest_id)
    .fetch_optional(&state.pool)
    .await;

    match job_result {
        Ok(Some(_)) => {
            // Spawn async ingest task
            let worker = state.ingest_worker.clone();
            let proj = project.clone();
            let id = ingest_id.clone();
            tokio::spawn(async move {
                if let Err(e) = worker.process_ingest(&proj, &id, records).await {
                    tracing::error!("Ingest failed: {}", e);
                }
            });

            HttpResponse::Accepted().json(json!({
                "ingest_id": ingest_id,
                "status": "pending",
                "status_url": format!("/memory/ingest/{}", ingest_id)
            }))
        }
        Ok(None) => {
            // Already exists
            HttpResponse::Conflict().json(json!({
                "error": "already_ingesting",
                "ingest_id": ingest_id
            }))
        }
        Err(e) => {
            tracing::error!("DB error: {}", e);
            HttpResponse::InternalServerError().json(json!({
                "error": "database_error"
            }))
        }
    }
}

/// GET /memory/ingest/{ingest_id} — check ingest status
pub async fn ingest_status(
    req: HttpRequest,
    ingest_id: web::Path<String>,
    state: web::Data<AppState>,
) -> HttpResponse {
    if let Err(e) = check_auth(&req, &state) {
        return e;
    }

    let id = ingest_id.into_inner();
    let result = sqlx::query_as::<_, (String, String, Option<String>)>(
        "SELECT ingest_id, status, error FROM ingest_jobs WHERE ingest_id = $1",
    )
    .bind(&id)
    .fetch_optional(&state.pool)
    .await;

    match result {
        Ok(Some((ingest_id, status, error))) => {
            HttpResponse::Ok().json(json!({
                "ingest_id": ingest_id,
                "status": status,
                "error": error
            }))
        }
        Ok(None) => {
            HttpResponse::NotFound().json(json!({"error": "not_found"}))
        }
        Err(_) => {
            HttpResponse::InternalServerError().json(json!({"error": "database_error"}))
        }
    }
}

/// GET /memory/query — semantic search across memories
pub async fn query_handler(
    req: HttpRequest,
    query: web::Query<std::collections::HashMap<String, String>>,
    state: web::Data<AppState>,
) -> HttpResponse {
    if let Err(e) = check_auth(&req, &state) {
        return e;
    }

    let project = match query.get("project") {
        Some(p) => p.clone(),
        None => {
            return HttpResponse::BadRequest().json(json!({"error": "missing project parameter"}))
        }
    };

    let question = match query.get("query") {
        Some(q) => q.clone(),
        None => {
            return HttpResponse::BadRequest().json(json!({"error": "missing query parameter"}))
        }
    };

    let limit = query
        .get("limit")
        .and_then(|l| l.parse::<i64>().ok())
        .unwrap_or(5);

    match state.query_worker.query(&project, &question, Some(limit)).await {
        Ok(results) => {
            HttpResponse::Ok().json(json!({
                "query": question,
                "project": project,
                "results": results
            }))
        }
        Err(e) => {
            tracing::error!("Query failed: {}", e);
            HttpResponse::InternalServerError().json(json!({"error": "query_failed"}))
        }
    }
}

/// GET /memory/projects — list projects with memory
pub async fn projects_handler(
    req: HttpRequest,
    state: web::Data<AppState>,
) -> HttpResponse {
    if let Err(e) = check_auth(&req, &state) {
        return e;
    }

    let result = sqlx::query_as::<_, (String,)>(
        "SELECT DISTINCT project FROM memories_l2 ORDER BY project",
    )
    .fetch_all(&state.pool)
    .await;

    match result {
        Ok(rows) => {
            let projects: Vec<String> = rows.into_iter().map(|(p,)| p).collect();
            HttpResponse::Ok().json(json!({
                "projects": projects,
                "count": projects.len()
            }))
        }
        Err(_) => {
            HttpResponse::InternalServerError().json(json!({"error": "database_error"}))
        }
    }
}

/// GET /memory/skills — list extracted skills
pub async fn skills_handler(
    req: HttpRequest,
    state: web::Data<AppState>,
) -> HttpResponse {
    if let Err(e) = check_auth(&req, &state) {
        return e;
    }

    let result = sqlx::query_as::<_, (String, String, String)>(
        "SELECT name, description, when_to_use FROM skills ORDER BY created_at DESC LIMIT 50",
    )
    .fetch_all(&state.pool)
    .await;

    match result {
        Ok(rows) => {
            let skills: Vec<serde_json::Value> = rows
                .into_iter()
                .map(|(name, desc, when_to_use)| {
                    json!({
                        "name": name,
                        "description": desc,
                        "when_to_use": when_to_use
                    })
                })
                .collect();
            HttpResponse::Ok().json(json!({
                "skills": skills,
                "count": skills.len()
            }))
        }
        Err(_) => {
            HttpResponse::InternalServerError().json(json!({"error": "database_error"}))
        }
    }
}