use crate::nips::nip01::Post;
use anyhow::{Context, Result};
use nostr_sdk::prelude::*;
use std::time::Duration;

/// Fetches a timeline/feed of posts from specific users (Followed users).
///
/// # Arguments
/// * `client` - The Nostr client.
/// * `followed_pubkeys` - A list of hex strings (bech32 also works if parsed correctly, but we assume hex or wait for parsing) representing the users to follow.
///
/// The function parses the keys, creates a filter, and returns a list of sorted Posts.
pub async fn get_followed_feed(
    client: &Client,
    followed_pubkeys: Vec<String>,
) -> Result<Vec<Post>> {
    let mut keys = Vec::new();
    for key in followed_pubkeys {
        // We try to parse each key. If one fails, we just ignore it or log it (here we context it).
        let pk = PublicKey::parse(&key).context(format!("Invalid public key: {}", key))?;
        keys.push(pk);
    }

    if keys.is_empty() {
        return Ok(Vec::new());
    }

    // Create a filter for Text Notes (Kind 1) from these authors
    let filter = Filter::new().kind(Kind::TextNote).authors(keys).limit(50); // Limit to 50 posts for now

    let timeout = Duration::from_secs(10);
    let events = client.fetch_events(filter, timeout).await?;

    // Convert Events to our Post struct
    let mut posts: Vec<Post> = events
        .into_iter()
        .map(|e| Post {
            id: e.id,
            author: e.pubkey,
            content: e.content.clone(),
            created_at: e.created_at,
        })
        .collect();

    // Sort by created_at descending (newest first)
    posts.sort_by(|a, b| b.created_at.cmp(&a.created_at));

    Ok(posts)
}

/// Fetches random (recent) posts from the connected Relays (Global Feed).
///
/// This is useful for discovery.
pub async fn get_random_posts(client: &Client) -> Result<Vec<Post>> {
    // Filter for any Text Note, limit 20
    let filter = Filter::new().kind(Kind::TextNote).limit(20);

    let timeout = Duration::from_secs(10);
    let events = client.fetch_events(filter, timeout).await?;

    let mut posts: Vec<Post> = events
        .into_iter()
        .map(|e| Post {
            id: e.id,
            author: e.pubkey,
            content: e.content.clone(),
            created_at: e.created_at,
        })
        .collect();

    // Sort by newest first
    posts.sort_by(|a, b| b.created_at.cmp(&a.created_at));

    Ok(posts)
}