use std::sync::Arc;
use std::time::Duration;

use tracing::{debug, warn};
use uuid::Uuid;

use crate::connect::ConnectClient;
use crate::proto::runner::v1::{LogRow, UpdateLogRequest};
use crate::state::RunnerState;

const POLL_INTERVAL: Duration = Duration::from_secs(3);

/// Streams logs from logs-service to Forgejo while a job is in-flight.
/// Runs until the stop signal is received (job completed).
/// Returns the final log index so the reporter can continue from there.
pub async fn stream_logs(
    client: Arc<ConnectClient>,
    state: Arc<RunnerState>,
    request_id: Uuid,
    task_id: i64,
    logs_base: String,
    mut stop: tokio::sync::watch::Receiver<bool>,
) -> i64 {
    let http = reqwest::Client::new();
    let mut log_index: i64 = 0;
    let mut last_total: i64 = 0;

    loop {
        // Check if we should stop
        if *stop.borrow() {
            // Do one final poll to catch any remaining logs
            log_index = poll_and_send(
                &client,
                &state,
                &http,
                &logs_base,
                request_id,
                task_id,
                log_index,
                &mut last_total,
            )
            .await;
            break;
        }

        log_index = poll_and_send(
            &client,
            &state,
            &http,
            &logs_base,
            request_id,
            task_id,
            log_index,
            &mut last_total,
        )
        .await;

        // Wait for the next poll interval or stop signal
        tokio::select! {
            _ = tokio::time::sleep(POLL_INTERVAL) => {}
            _ = stop.changed() => {
                // Signal changed — do one more poll then exit
                log_index = poll_and_send(
                    &client, &state, &http, &logs_base,
                    request_id, task_id, log_index, &mut last_total,
                ).await;
                break;
            }
        }
    }

    debug!(task_id, log_index, "log streamer stopped");
    log_index
}

/// Log category summary from logs-service.
#[derive(serde::Deserialize)]
struct LogCategorySummary {
    category: String,
    count: i64,
}

async fn poll_and_send(
    client: &ConnectClient,
    state: &RunnerState,
    http: &reqwest::Client,
    logs_base: &str,
    request_id: Uuid,
    task_id: i64,
    current_index: i64,
    last_total: &mut i64,
) -> i64 {
    // Get total log count across all categories
    let categories_url = format!(
        "{}/jobs/{}/logs",
        logs_base.trim_end_matches('/'),
        request_id
    );

    let categories = match http.get(&categories_url).send().await {
        Ok(resp) if resp.status().is_success() => resp
            .json::<Vec<LogCategorySummary>>()
            .await
            .unwrap_or_default(),
        _ => return current_index,
    };

    let new_total: i64 = categories.iter().map(|c| c.count).sum();
    if new_total <= *last_total {
        return current_index; // No new logs
    }
    *last_total = new_total;

    // Fetch all logs and send new ones
    // We re-fetch everything but only send lines from current_index onward.
    // This is simple but not optimal for large logs — good enough for streaming.
    let mut all_lines: Vec<String> = Vec::new();
    for cat in &categories {
        let url = format!(
            "{}/jobs/{}/logs/{}",
            logs_base.trim_end_matches('/'),
            request_id,
            cat.category
        );
        if let Ok(resp) = http.get(&url).send().await {
            if resp.status().is_success() {
                if let Ok(text) = resp.text().await {
                    all_lines.push(format!("::group::{}", cat.category));
                    for line in text.lines() {
                        all_lines.push(line.to_string());
                    }
                    all_lines.push("::endgroup::".to_string());
                }
            }
        }
    }

    let total_lines = all_lines.len() as i64;
    if total_lines <= current_index {
        return current_index;
    }

    // Send only new lines
    let new_lines = &all_lines[current_index as usize..];
    if new_lines.is_empty() {
        return current_index;
    }

    let now = prost_types::Timestamp {
        seconds: time::OffsetDateTime::now_utc().unix_timestamp(),
        nanos: 0,
    };

    let rows: Vec<LogRow> = new_lines
        .iter()
        .map(|line| LogRow {
            time: Some(now.clone()),
            content: line.clone(),
        })
        .collect();

    let req = UpdateLogRequest {
        task_id,
        index: current_index,
        rows,
        no_more: false,
    };

    match client
        .update_log(&req, &state.identity.uuid, &state.identity.token)
        .await
    {
        Ok(resp) => {
            debug!(
                task_id,
                new_lines = new_lines.len(),
                ack_index = resp.ack_index,
                "streamed logs"
            );
            resp.ack_index
        }
        Err(e) => {
            warn!(error = %e, task_id, "failed to stream logs");
            current_index
        }
    }
}