use std::sync::Arc;

use axum::{
    extract::{Query, State},
    Json,
};
use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};

use crate::api::error::ApiError;
use crate::db;
use crate::records::{ShardView, SHARD_COLLECTION};
use crate::AppState;

#[derive(Debug, Deserialize)]
pub struct ListShardsParams {
    pub author: Option<String>,
    pub limit: Option<i64>,
    pub cursor: Option<String>,
}

#[derive(Debug, Serialize)]
pub struct ListShardsResponse {
    pub shards: Vec<ShardView>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub cursor: Option<String>,
}

pub async fn list_shards(
    State(state): State<Arc<AppState>>,
    Query(params): Query<ListShardsParams>,
) -> Result<Json<ListShardsResponse>, ApiError> {
    let author = params.author.ok_or_else(|| {
        ApiError::InvalidRequest("Missing required parameter: author".to_string())
    })?;

    let limit = params.limit.unwrap_or(50).min(100).max(1);
    let cursor: Option<DateTime<Utc>> = params
        .cursor
        .as_ref()
        .and_then(|c| DateTime::parse_from_rfc3339(c).ok())
        .map(|dt| dt.with_timezone(&Utc));

    let records =
        db::list_records_by_creator(state.db.pool(), SHARD_COLLECTION, &author, cursor, limit)
            .await?;

    let next_cursor = records.last().map(|r| r.indexed_at.to_rfc3339());
    let views: Vec<ShardView> = records.into_iter().map(ShardView::from).collect();

    Ok(Json(ListShardsResponse {
        shards: views,
        cursor: next_cursor,
    }))
}