//! The harness's events as terminal rows: what the per-agent web UI's
//! live/history endpoints serve for the "terminal" event stream, as opposed to
//! agent-state changes (`StatusChanged`/`ModelChanged`/`EffortChanged`/
//! `TokenUsageChanged`/`TurnStateChanged`), which have never rendered as
//! terminal rows (the header/badges poll `/api/state`, not this stream) and
//! produce zero [`TermMsg`]s here.
//!
//! One [`crate::events::LiveEvent`] maps to zero or more `TermMsg`s — most
//! map to exactly one, but `LiveEvent::Stream` (one raw claude
//! `stream-json` line) can expand to several: an `assistant` message with
//! both a text block and a `tool_use` block produces two rows.

pub use hive_sh4re::term_msg::{ClassifyCtx, Level, TermMsg, iso8601_utc};
use hive_types::term_msg::{TURN_ICON, TURN_SUMMARY_PREFIX};

use crate::events::LiveEvent;

/// Classify one [`LiveEvent`] into zero or more terminal rows, each
/// stamped with `ts` — the event's own unix-seconds time, from the bus on
/// the live path and from the `events` table on replay.
///
/// The stamp is applied here, over the rows the classifiers return, so that
/// every row the harness puts on a wire carries one.
pub fn classify(ev: &LiveEvent, ts: i64, ctx: &mut ClassifyCtx) -> Vec<TermMsg> {
    let ts = iso8601_utc(ts);
    classify_rows(ev, ctx)
        .into_iter()
        .map(|m| m.at(ts.as_str()))
        .collect()
}

fn classify_rows(ev: &LiveEvent, ctx: &mut ClassifyCtx) -> Vec<TermMsg> {
    match ev {
        LiveEvent::TurnStart { from, body, .. } => {
            // `unread` (the third field) was dropped — mara: "i can see
            // the todo/inbox count in toolbar and dont need the N unread".
            let mut m =
                TermMsg::new(Level::Info, format!("{TURN_SUMMARY_PREFIX}{from}")).icon(TURN_ICON);
            if !body.trim().is_empty() {
                m = m.body(body.clone(), None);
            }
            vec![m]
        }
        LiveEvent::TurnEnd { ok, note } => {
            let msg = if *ok {
                TermMsg::new(Level::Info, "turn ok").icon("✅")
            } else {
                let summary = note
                    .as_deref()
                    .filter(|n| !n.is_empty())
                    .map_or_else(|| "turn fail".to_owned(), |n| format!("turn fail — {n}"));
                TermMsg::new(Level::Error, summary).icon("❌")
            };
            vec![msg]
        }
        LiveEvent::Note { text } => vec![classify_note(text)],
        LiveEvent::Stream(v) => hive_sh4re::stream_enrich::classify_stream_value(v, ctx),
        // Agent-state transitions never render as terminal rows — the
        // header/badges read `/api/state`, not this stream (see module doc).
        LiveEvent::StatusChanged { .. }
        | LiveEvent::ModelChanged { .. }
        | LiveEvent::EffortChanged { .. }
        | LiveEvent::TokenUsageChanged { .. }
        | LiveEvent::TurnStateChanged { .. } => vec![],
    }
}

fn classify_note(text: &str) -> TermMsg {
    if let Some(rest) = text.strip_prefix("stderr:") {
        TermMsg::new(Level::Warn, format!("stderr:{rest}"))
    } else if let Some(rest) = text.strip_prefix("operator:") {
        TermMsg::new(Level::Info, format!("operator:{rest}"))
    } else {
        // Ambient harness chatter (session archived, plugin loaded, etc.) —
        // routine, not worth the same visual weight as a tool call or
        // assistant text.
        TermMsg::new(Level::Debug, text.to_owned())
    }
}

#[cfg(test)]
mod tests {
    use super::{ClassifyCtx, Level, classify, iso8601_utc};
    use crate::events::LiveEvent;

    /// A fixed event time and the exact string it must render as. Fixed on
    /// both sides on purpose: a stamp taken from the clock would render to
    /// a different string on every run, and a test that can only assert
    /// "some string" passes just as happily against `now()`.
    const EVENT_TS: i64 = 1_789_302_903;
    const EVENT_TS_ISO: &str = "2026-09-13T12:35:03Z";

    #[test]
    fn turn_start_carries_from_and_body_no_unread() {
        let ev = LiveEvent::TurnStart {
            from: "operator".into(),
            body: "sweep the backlog".into(),
            unread: 3,
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].summary, "TURN ← operator");
        assert_eq!(msgs[0].body.as_deref(), Some("sweep the backlog"));
        assert_eq!(msgs[0].level, Level::Info);
    }

    #[test]
    fn turn_start_empty_body_has_no_body() {
        let ev = LiveEvent::TurnStart {
            from: "reminder".into(),
            body: String::new(),
            unread: 0,
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert!(msgs[0].body.is_none());
    }

    #[test]
    fn turn_end_ok_is_info() {
        let ev = LiveEvent::TurnEnd {
            ok: true,
            note: None,
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert_eq!(msgs[0].level, Level::Info);
        assert_eq!(msgs[0].summary, "turn ok");
    }

    #[test]
    fn turn_end_fail_is_error_with_note() {
        let ev = LiveEvent::TurnEnd {
            ok: false,
            note: Some("rate limited".into()),
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert_eq!(msgs[0].level, Level::Error);
        assert_eq!(msgs[0].summary, "turn fail — rate limited");
    }

    #[test]
    fn note_stderr_is_warn() {
        let ev = LiveEvent::Note {
            text: "stderr: warning: deprecated flag".into(),
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert_eq!(msgs[0].level, Level::Warn);
    }

    #[test]
    fn note_operator_is_info() {
        let ev = LiveEvent::Note {
            text: "operator: /compact requested".into(),
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert_eq!(msgs[0].level, Level::Info);
    }

    #[test]
    fn note_plain_is_debug() {
        let ev = LiveEvent::Note {
            text: "created fresh session".into(),
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert_eq!(msgs[0].level, Level::Debug);
    }

    #[test]
    fn agent_state_events_produce_no_rows() {
        let mut ctx = ClassifyCtx::default();
        assert!(
            classify(
                &LiveEvent::StatusChanged {
                    status: "online".into()
                },
                EVENT_TS,
                &mut ctx
            )
            .is_empty()
        );
        assert!(
            classify(
                &LiveEvent::ModelChanged {
                    model: "opus".into()
                },
                EVENT_TS,
                &mut ctx
            )
            .is_empty()
        );
    }

    /// The point of the field: a row replayed out of history says when the
    /// thing happened, not when it was read. Asserting the exact rendering
    /// of a fixed input is what makes this a test — stamping `now()`
    /// instead produces today's date and fails here.
    #[test]
    fn a_row_carries_the_time_of_the_event_it_came_from() {
        let ev = LiveEvent::Note {
            text: "created fresh session".into(),
        };
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert_eq!(msgs[0].ts, EVENT_TS_ISO);
    }

    /// One `stream-json` line expanding into several rows gives all of them
    /// the same time: they are one event, and rows that disagreed about
    /// when they happened would sort against each other downstream.
    #[test]
    fn every_row_one_event_expands_into_shares_that_time() {
        let ev = LiveEvent::Stream(serde_json::json!({
            "type": "assistant",
            "message": {
                "content": [
                    { "type": "text", "text": "looking at it" },
                    {
                        "type": "tool_use",
                        "id": "toolu_1",
                        "name": "Read",
                        "input": { "file_path": "/src/main.rs" }
                    }
                ]
            }
        }));
        let mut ctx = ClassifyCtx::default();
        let msgs = classify(&ev, EVENT_TS, &mut ctx);
        assert!(msgs.len() > 1, "this fixture must expand to several rows");
        for m in &msgs {
            assert_eq!(
                m.ts, EVENT_TS_ISO,
                "row {:?} lost the event's time",
                m.summary
            );
        }
    }

    /// UTC, with no dependence on the machine's zone: the rendering of a
    /// fixed stamp is the same everywhere, and the `Z` says so on the wire.
    #[test]
    fn the_stamp_renders_as_utc_whatever_the_local_zone_is() {
        assert_eq!(iso8601_utc(EVENT_TS), EVENT_TS_ISO);
        assert_eq!(iso8601_utc(0), "1970-01-01T00:00:00Z");
        // Out of range for a representable date; the epoch stands in rather
        // than the row losing its stamp entirely.
        assert_eq!(iso8601_utc(i64::MAX), "1970-01-01T00:00:00Z");
    }
}