use std::time::Duration;

use axum::Router;
use tokio::time::timeout;
use tower_http::cors::{Any, CorsLayer};

use crate::core::cache::{MongoCache, RedisCache};
use crate::core::db::{Database, PostgresDb, QdrantDb};
use crate::Embedder;

use super::agent_api;
use super::agent_search;
use super::auth;
use super::docs;
use super::files;
use super::five_w1h_agent_api;
use super::health;
use super::identities;
use super::identity_agent_api;
use super::identity_api;
use super::identity_binding;
use super::llm_search;
use super::pipeline;
use super::media_api;
use super::middleware::unified_auth;
use super::processing;
use super::scan;
use super::search::search_routes;
use super::tmdb_api;
use super::trace_agent_api;
use super::types::AppState;
use super::universal_search::universal_search_routes;

pub async fn start_server(host: &str, port: u16) -> anyhow::Result<()> {
    health::init_server_state(host, port);

    let embedder = std::sync::Arc::new(Embedder::new("embeddinggemma-300m".to_string()));

    // ── ⚠️ WARNING: DO NOT move MongoCache::init() back to critical path ──
    //
    // MongoDB is ONLY a cache layer — if unavailable, the server MUST still
    // start with Redis cache alone. This keeps 3002 bootable on machines
    // without MongoDB installed. If you add a new dependency here, ask:
    //   "Can this service degrade gracefully if the dependant is missing?"
    //
    // See also: MongoCache::disabled() in mongo_cache.rs
    let mongo_cache = match timeout(Duration::from_secs(5), MongoCache::init()).await {
        Ok(Ok(cache)) => cache,
        Ok(Err(e)) => {
            tracing::warn!("MongoDB cache unavailable (continuing without): {e}");
            MongoCache::disabled().await
        }
        Err(_) => {
            tracing::warn!("MongoDB init timed out (continuing without cache)");
            MongoCache::disabled().await
        }
    };
    let redis_cache = RedisCache::new()?;
    let db = PostgresDb::init().await?;

    // Run migrations (create identity_history table if not exists)
    PostgresDb::run_migrations(db.pool()).await?;

    let schema_health = health::check_schema_migrations(db.pool()).await;
    if schema_health.ok {
        tracing::info!(
            "[SCHEMA] All {}/{} required migrations applied ✓",
            schema_health.required.len(),
            schema_health.required.len()
        );
    } else if !schema_health.table_exists {
        tracing::warn!("[SCHEMA] schema_migrations table not found!");
    } else {
        let missing: Vec<&str> = schema_health
            .required
            .iter()
            .filter(|req| {
                !schema_health
                    .applied
                    .iter()
                    .any(|app| app.filename == req.filename && app.checksum == req.checksum)
            })
            .map(|m| m.filename.as_str())
            .collect();
        tracing::warn!(
            "[SCHEMA] {}/{} migrations match. Missing: {}",
            schema_health.applied.len(),
            schema_health.required.len(),
            missing.join(", ")
        );
    }

    let db = std::sync::Arc::new(db);
    let api_state = super::middleware::ApiState { db: db.clone() };

    let qdrant = std::sync::Arc::new(QdrantDb::new());
    let state = AppState {
        db,
        qdrant,
        embedder,
        embedder_model: "nomic-embed-text-v2-moe:latest".to_string(),
        mongo_cache,
        redis_cache,
        api_state,
    };

    let protected_routes = Router::new()
        .merge(files::file_routes())
        .merge(scan::scan_routes())
        .merge(identity_binding::identity_binding_routes())
        .merge(identities::identity_routes())
        .merge(tmdb_api::tmdb_routes())
        .merge(identity_api::identity_routes())
        .merge(agent_api::agent_routes())
        .merge(agent_search::agent_search_routes())
        .merge(processing::processing_routes())
        .merge(identity_agent_api::identity_agent_routes())
        .merge(five_w1h_agent_api::five_w1h_agent_routes())
        .merge(media_api::bbox_routes())
        .merge(trace_agent_api::trace_agent_routes())
        .merge(search_routes())
        .merge(llm_search::llm_smart_routes())
        .merge(universal_search_routes())
        .merge(pipeline::pipeline_routes())
        .layer(axum::middleware::from_fn_with_state(
            state.api_state.clone(),
            unified_auth,
        ))
        .with_state(state.clone());

    let cors = CorsLayer::new()
        .allow_origin(Any)
        .allow_methods(Any)
        .allow_headers(Any);

    let app = Router::new()
        .merge(auth::auth_routes())
        .merge(health::health_routes())
        .merge(docs::doc_routes())
        .merge(protected_routes)
        .layer(cors)
        .with_state(state);

    let addr: std::net::SocketAddr = format!("{}:{}", host, port).parse().unwrap();
    tracing::info!("Starting API server at http://{}", addr);

    let listener = tokio::net::TcpListener::bind(addr).await?;
    axum::serve(listener, app).await?;

    Ok(())
}