//! timeline: one chronological view over the event journal and the REPL
//! command history.

use super::*;
use crate::events::{self, Event};
use crate::history::{self, HistoryEntry};
use crate::output::print_json;
use anyhow::Result;
use serde::Serialize;

#[derive(Debug, Clone, Serialize)]
pub struct TimelineRow {
    pub ts: String,
    pub source: String,
    pub kind: String,
    pub agent: Option<String>,
    pub summary: String,
}

/// Merge events and history entries into one chronological list, most
/// recent first, filtered by agent/project/date and capped by limit.
pub fn collect(
    app: &App,
    agent: Option<&str>,
    project: Option<&str>,
    since: Option<&str>,
    limit: usize,
) -> Result<Vec<TimelineRow>> {
    let cut = match since {
        Some(s) => Some(crate::commands::log_cmd::parse_since(s)?),
        None => None,
    };
    let mut rows: Vec<TimelineRow> = Vec::new();
    for ev in events::read_events(&app.events_dir(), 0) {
        if agent.map_or(true, |a| ev.agent.as_deref() == Some(a))
            && project.map_or(true, |p| ev.project.as_deref() == Some(p))
        {
            if let Some(c) = cut {
                if chrono::DateTime::parse_from_rfc3339(&ev.ts)
                    .map(|t| t < c)
                    .unwrap_or(true)
                {
                    continue;
                }
            }
            rows.push(event_row(&ev));
        }
    }
    // REPL history entries carry no agent/project: include them only
    // when no such filter is set.
    if agent.is_none() && project.is_none() {
        for (_, e) in crate::commands::history_cmd::filter(app, None, None, None, false, None, 0) {
            let ts_ok = match cut {
                Some(c) => chrono::DateTime::parse_from_rfc3339(&e.ts)
                    .map(|t| t >= c)
                    .unwrap_or(false),
                None => true,
            };
            if !ts_ok {
                continue;
            }
            rows.push(TimelineRow {
                ts: e.ts.clone(),
                source: "repl".to_string(),
                kind: e.kind.clone(),
                agent: e.agent.clone(),
                summary: e.cmd.clone(),
            });
        }
    }
    rows.sort_by(|a, b| b.ts.cmp(&a.ts));
    rows.truncate(if limit > 0 { limit } else { rows.len() });
    Ok(rows)
}

fn event_row(ev: &Event) -> TimelineRow {
    let mut parts = Vec::new();
    if let Some(p) = ev.pid {
        parts.push(format!("pid {p}"));
    }
    if let Some(d) = ev.duration_s {
        parts.push(format!("{d}s"));
    }
    if let Some(c) = ev.exit_code {
        parts.push(format!("exit {c}"));
    }
    TimelineRow {
        ts: ev.ts.clone(),
        source: "journal".to_string(),
        kind: ev.kind.as_str().to_string(),
        agent: ev.agent.clone(),
        summary: if parts.is_empty() {
            ev.project.clone().unwrap_or_default()
        } else {
            parts.join(", ")
        },
    }
}

pub fn run(
    app: &App,
    agent: Option<&str>,
    project: Option<&str>,
    since: Option<&str>,
    limit: usize,
) -> Result<i32> {
    let rows = collect(app, agent, project, since, limit)?;
    if app.json() {
        print_json(&rows);
        return Ok(0);
    }
    for r in &rows {
        let ts = r.ts.get(0..16).unwrap_or(&r.ts);
        let actor = r.agent.as_deref().unwrap_or("repl");
        println!("{ts}  {:<9} {:<16} {}", r.kind, actor, r.summary);
    }
    if rows.is_empty() {
        app.log.info("no activity recorded yet");
    }
    Ok(0)
}

#[cfg(test)]
mod tests {
    use super::*;
    use clap::Parser;

    fn app_with(lines: &[&str]) -> App {
        let guard = tempfile::tempdir().unwrap();
        let dir = guard.path().to_path_buf();
        std::mem::forget(guard);
        let cfg = dir.join("config.yaml");
        std::fs::write(
            &cfg,
            concat!(
                "version: \"1.0\"\n",
                "settings:\n",
                "  auto_install_deps: false\n",
                "agents: []\n",
            ),
        )
        .unwrap();
        let cli = crate::cli::Cli::parse_from(["am", "--config", cfg.to_str().unwrap()]);
        let mut app = App::from_cli(cli).unwrap();
        let mut p = app.paths.clone();
        p.install_dir = dir.join("agents");
        p.bin_dir = dir.join("agents").join("bin");
        p.log_dir = dir.join("logs");
        p.state_file = dir.join("state.json");
        p.probe_cache_file = dir.join("probe-cache.json");
        p.config_dir = Some(dir.join("config"));
        app.paths = p;
        let month = chrono::Utc::now().format("%Y%m");
        let path = dir.join(format!("events-{month}.jsonl"));
        std::fs::create_dir_all(&dir).unwrap();
        std::fs::write(&path, lines.join("\n")).unwrap();
        app
    }

    #[test]
    fn merges_events_and_history_chronologically() {
        let app = app_with(&[
            r#"{"ts":"2026-08-01T10:00:00Z","kind":"run","agent":"a","exit_code":0,"duration_s":5}"#,
            r#"{"ts":"2026-08-03T10:00:00Z","kind":"start","agent":"a","pid":42}"#,
        ]);
        history::record(&app, "s1", &history::HistoryEntry::now("list --all")).unwrap();
        let rows = collect(&app, None, None, None, 0).unwrap();
        assert!(rows.len() >= 3, "events + history: {rows:?}");
        // Ordre antichronologique strict.
        let ts: Vec<&str> = rows.iter().map(|r| r.ts.as_str()).collect();
        let mut sorted = ts.clone();
        sorted.sort_by(|a, b| b.cmp(a));
        assert_eq!(ts, sorted);
        // Filtres.
        assert_eq!(collect(&app, Some("a"), None, None, 0).unwrap().len(), 2);
        assert_eq!(collect(&app, Some("zzz"), None, None, 0).unwrap().len(), 0);
        assert_eq!(collect(&app, None, None, None, 2).unwrap().len(), 2);
    }
}