use std::sync::Arc;
use axum::{
    extract::{Path, State},
    http::StatusCode,
    response::{IntoResponse, Response},
    routing::get,
    Json, Router,
};
use serde::Deserialize;
use crate::AppState;
use crate::db::Timer;

type ApiResult<T> = Result<Json<T>, Response>;

fn db_err(e: sqlx::Error) -> Response {
    tracing::error!("Database error: {}", e);
    (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response()
}

#[derive(Deserialize)]
pub struct CreateTimer {
    pub name: String,
    pub interval_secs: i64,
    pub requirement: String,
}

#[derive(Deserialize)]
pub struct UpdateTimer {
    pub name: Option<String>,
    pub interval_secs: Option<i64>,
    pub requirement: Option<String>,
    pub enabled: Option<bool>,
}

pub fn router(state: Arc<AppState>) -> Router {
    Router::new()
        .route("/projects/{id}/timers", get(list_timers).post(create_timer))
        .route("/timers/{id}", get(get_timer).put(update_timer).delete(delete_timer))
        .with_state(state)
}

async fn list_timers(
    State(state): State<Arc<AppState>>,
    Path(project_id): Path<String>,
) -> ApiResult<Vec<Timer>> {
    sqlx::query_as::<_, Timer>(
        "SELECT * FROM timers WHERE project_id = ? ORDER BY created_at DESC"
    )
    .bind(&project_id)
    .fetch_all(&state.db.pool)
    .await
    .map(Json)
    .map_err(db_err)
}

async fn create_timer(
    State(state): State<Arc<AppState>>,
    Path(project_id): Path<String>,
    Json(input): Json<CreateTimer>,
) -> ApiResult<Timer> {
    if input.interval_secs < 60 {
        return Err((StatusCode::BAD_REQUEST, "Minimum interval is 60 seconds").into_response());
    }

    let id = uuid::Uuid::new_v4().to_string();
    sqlx::query_as::<_, Timer>(
        "INSERT INTO timers (id, project_id, name, interval_secs, requirement) VALUES (?, ?, ?, ?, ?) RETURNING *"
    )
    .bind(&id)
    .bind(&project_id)
    .bind(&input.name)
    .bind(input.interval_secs)
    .bind(&input.requirement)
    .fetch_one(&state.db.pool)
    .await
    .map(Json)
    .map_err(db_err)
}

async fn get_timer(
    State(state): State<Arc<AppState>>,
    Path(timer_id): Path<String>,
) -> ApiResult<Timer> {
    sqlx::query_as::<_, Timer>("SELECT * FROM timers WHERE id = ?")
        .bind(&timer_id)
        .fetch_optional(&state.db.pool)
        .await
        .map_err(db_err)?
        .map(Json)
        .ok_or_else(|| (StatusCode::NOT_FOUND, "Timer not found").into_response())
}

async fn update_timer(
    State(state): State<Arc<AppState>>,
    Path(timer_id): Path<String>,
    Json(input): Json<UpdateTimer>,
) -> ApiResult<Timer> {
    // Fetch existing
    let existing = sqlx::query_as::<_, Timer>("SELECT * FROM timers WHERE id = ?")
        .bind(&timer_id)
        .fetch_optional(&state.db.pool)
        .await
        .map_err(db_err)?;

    let Some(existing) = existing else {
        return Err((StatusCode::NOT_FOUND, "Timer not found").into_response());
    };

    let name = input.name.unwrap_or(existing.name);
    let interval_secs = input.interval_secs.unwrap_or(existing.interval_secs);
    let requirement = input.requirement.unwrap_or(existing.requirement);
    let enabled = input.enabled.unwrap_or(existing.enabled);

    if interval_secs < 60 {
        return Err((StatusCode::BAD_REQUEST, "Minimum interval is 60 seconds").into_response());
    }

    sqlx::query_as::<_, Timer>(
        "UPDATE timers SET name = ?, interval_secs = ?, requirement = ?, enabled = ? WHERE id = ? RETURNING *"
    )
    .bind(&name)
    .bind(interval_secs)
    .bind(&requirement)
    .bind(enabled)
    .bind(&timer_id)
    .fetch_one(&state.db.pool)
    .await
    .map(Json)
    .map_err(db_err)
}

async fn delete_timer(
    State(state): State<Arc<AppState>>,
    Path(timer_id): Path<String>,
) -> Result<StatusCode, Response> {
    let result = sqlx::query("DELETE FROM timers WHERE id = ?")
        .bind(&timer_id)
        .execute(&state.db.pool)
        .await
        .map_err(db_err)?;

    if result.rows_affected() > 0 {
        Ok(StatusCode::NO_CONTENT)
    } else {
        Err((StatusCode::NOT_FOUND, "Timer not found").into_response())
    }
}