tokmesh-core 0.1.2

//! OpenCodeReview session parser
//!
//! OpenCodeReview stores sessions as JSONL files under
//! `~/.opencodereview/sessions/<encoded-repo-path>/<session-id>.jsonl`.

use super::utils::{back_anchor_timestamp, file_modified_timestamp_ms, parse_timestamp_value};
use super::UnifiedMessage;
use crate::{pricing, provider_identity, TokenBreakdown};
use serde_json::Value;
use std::collections::HashSet;
use std::io::{BufRead, BufReader};
use std::path::Path;

pub fn parse_opencodereview_file(path: &Path) -> Vec<UnifiedMessage> {
    let file = match std::fs::File::open(path) {
        Ok(f) => f,
        Err(_) => return Vec::new(),
    };

    let session_id = session_id_from_path(path);
    let fallback_timestamp = file_modified_timestamp_ms(path);

    let mut workspace: Option<String> = None;
    let mut messages = Vec::new();
    let mut seen = HashSet::new();

    for (line_index, line) in BufReader::new(file).lines().enumerate() {
        let Ok(line) = line else { continue };

        if !line.contains("llm_response") && !line.contains("session_start") {
            continue;
        }

        let Ok(value) = serde_json::from_str::<Value>(&line) else {
            continue;
        };

        let record_type = value.get("type").and_then(Value::as_str).unwrap_or("");

        if record_type == "session_start" {
            if workspace.is_none() {
                workspace = value.get("cwd").and_then(Value::as_str).map(str::to_string);
            }
            continue;
        }

        if record_type != "llm_response" {
            continue;
        }

        let usage = match value.get("usage") {
            Some(u) => u,
            None => continue,
        };

        let tokens = tokens_from_usage(usage);
        if tokens.total() == 0 {
            continue;
        }

        // `explicit_timestamp` is this record's own recorded `timestamp`
        // field, as opposed to `fallback_timestamp` (a file-mtime fallback
        // used when it's absent or unparseable).
        let explicit_timestamp = value.get("timestamp").and_then(parse_timestamp_value);
        let recorded_timestamp = explicit_timestamp.unwrap_or(fallback_timestamp);

        let model_raw = value
            .get("model")
            .and_then(Value::as_str)
            .unwrap_or("unknown");
        let model_id = pricing::aliases::resolve_alias(model_raw)
            .unwrap_or(model_raw)
            .to_string();

        let provider_id = provider_identity::inferred_provider_from_model(&model_id)
            .map(str::to_string)
            .unwrap_or_else(|| "opencodereview".to_string());

        let duration_ms = value
            .get("duration_ms")
            .and_then(Value::as_i64)
            .filter(|d| *d > 0);

        // The `llm_response` record's `timestamp` is written when the
        // response is logged, i.e. the call's *end*, not its start.
        // `duration_ms` is that call's elapsed time, so sessionize()'s
        // `[timestamp, timestamp + duration_ms]` span would otherwise
        // project forward past the actual completion into phantom idle time.
        // Back-calculate the start anchor the same way used for Copilot's
        // `endTime`-only records.
        //
        // Only do this when `explicit_timestamp` is a real recorded end
        // timestamp: when it's absent, `recorded_timestamp` is
        // `fallback_timestamp` (the file's mtime), not this record's own end
        // time, and subtracting `duration_ms` from it would shift the
        // message into the wrong day rather than anchor it correctly.
        let timestamp = match (explicit_timestamp, duration_ms) {
            (Some(end), Some(duration)) => back_anchor_timestamp(end, duration),
            _ => recorded_timestamp,
        };

        // Timestamped duplicate rows are replayed writes of the same call and
        // retain the historical key. Timestampless rows all share file mtime,
        // so use their stable file line to keep distinct calls distinct.
        let line_discriminator = match explicit_timestamp {
            Some(_) => String::new(),
            None => format!(":line{line_index}"),
        };
        let dedup_key = format!(
            "opencodereview:{session_id}:{recorded_timestamp}:{model_id}:{}:{}:{}:{}{line_discriminator}",
            tokens.input, tokens.output, tokens.cache_read, tokens.cache_write,
        );
        if !seen.insert(dedup_key.clone()) {
            continue;
        }

        let mut msg = UnifiedMessage::new(
            "opencodereview",
            model_id,
            provider_id,
            &session_id,
            timestamp,
            tokens,
            0.0,
        );
        msg.dedup_key = Some(dedup_key);
        msg.duration_ms = duration_ms;

        if let Some(ws) = &workspace {
            if let Some(key) = super::normalize_workspace_key(ws) {
                msg.workspace_label = super::workspace_label_from_key(&key);
                msg.workspace_key = Some(key);
            }
        }

        messages.push(msg);
    }

    messages
}

fn session_id_from_path(path: &Path) -> String {
    path.file_stem()
        .and_then(|s| s.to_str())
        .filter(|s| !s.trim().is_empty())
        .unwrap_or("unknown")
        .to_string()
}

fn tokens_from_usage(usage: &Value) -> TokenBreakdown {
    TokenBreakdown {
        input: number_field(usage, "prompt_tokens"),
        output: number_field(usage, "completion_tokens"),
        cache_read: number_field(usage, "cache_read_tokens"),
        cache_write: number_field(usage, "cache_write_tokens"),
        reasoning: 0,
    }
}

fn number_field(value: &Value, field: &str) -> i64 {
    value
        .get(field)
        .and_then(|v| {
            v.as_i64()
                .or_else(|| v.as_u64().map(|u| i64::try_from(u).unwrap_or(i64::MAX)))
        })
        .unwrap_or(0)
        .max(0)
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::io::Write;
    use tempfile::TempDir;

    fn parse_events(content: &str) -> Vec<UnifiedMessage> {
        let dir = TempDir::new().unwrap();
        let repo_dir = dir.path().join("test-repo");
        std::fs::create_dir_all(&repo_dir).unwrap();
        let path = repo_dir.join("test-session-123.jsonl");
        let mut file = std::fs::File::create(&path).unwrap();
        file.write_all(content.as_bytes()).unwrap();
        file.flush().unwrap();
        parse_opencodereview_file(&path)
    }

    fn session_start(cwd: &str) -> String {
        format!(
            r#"{{"type":"session_start","sessionId":"test-session-123","timestamp":"2026-01-15T10:00:00Z","cwd":"{cwd}","model":"claude-sonnet-4-20250514"}}"#
        )
    }

    fn llm_response(
        timestamp: &str,
        model: &str,
        prompt: i64,
        completion: i64,
        cache_read: i64,
        cache_write: i64,
    ) -> String {
        format!(
            r#"{{"type":"llm_response","sessionId":"test-session-123","timestamp":"{timestamp}","model":"{model}","duration_ms":1500,"usage":{{"prompt_tokens":{prompt},"completion_tokens":{completion},"cache_read_tokens":{cache_read},"cache_write_tokens":{cache_write}}}}}"#
        )
    }

    fn llm_response_without_timestamp(
        model: &str,
        duration_ms: i64,
        prompt: i64,
        completion: i64,
    ) -> String {
        format!(
            r#"{{"type":"llm_response","sessionId":"test-session-123","model":"{model}","duration_ms":{duration_ms},"usage":{{"prompt_tokens":{prompt},"completion_tokens":{completion},"cache_read_tokens":0,"cache_write_tokens":0}}}}"#
        )
    }

    #[test]
    fn parses_single_llm_response() {
        let content = format!(
            "{}\n{}\n",
            session_start("/home/user/project"),
            llm_response(
                "2026-01-15T10:00:05Z",
                "claude-sonnet-4-20250514",
                1000,
                200,
                500,
                100
            ),
        );
        let msgs = parse_events(&content);

        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].client, "opencodereview");
        assert_eq!(msgs[0].tokens.input, 1000);
        assert_eq!(msgs[0].tokens.output, 200);
        assert_eq!(msgs[0].tokens.cache_read, 500);
        assert_eq!(msgs[0].tokens.cache_write, 100);
        assert_eq!(msgs[0].tokens.reasoning, 0);
        assert_eq!(msgs[0].duration_ms, Some(1500));
        assert_eq!(msgs[0].session_id, "test-session-123");
        assert!(msgs[0].workspace_key.is_some());
    }

    #[test]
    fn clamps_extreme_unsigned_usage_and_keeps_the_message() {
        let content = format!(
            "{}\n{}\n",
            session_start("/home/user/project"),
            r#"{"type":"llm_response","sessionId":"test-session-123","timestamp":"2026-01-15T10:00:05Z","model":"gpt-4o","duration_ms":1500,"usage":{"prompt_tokens":18446744073709551615,"completion_tokens":9223372036854775807,"cache_read_tokens":-1,"cache_write_tokens":0}}"#,
        );
        let msgs = parse_events(&content);

        assert_eq!(
            msgs.len(),
            1,
            "one extreme bucket must not drop the message"
        );
        assert_eq!(msgs[0].tokens.input, i64::MAX);
        assert_eq!(msgs[0].tokens.output, i64::MAX);
        assert_eq!(msgs[0].tokens.cache_read, 0);
        assert_eq!(msgs[0].tokens.cache_write, 0);
    }

    #[test]
    fn parses_multiple_responses() {
        let content = format!(
            "{}\n{}\n{}\n",
            session_start("/home/user/project"),
            llm_response(
                "2026-01-15T10:00:05Z",
                "claude-sonnet-4-20250514",
                1000,
                200,
                0,
                0
            ),
            llm_response("2026-01-15T10:01:00Z", "gpt-4o", 500, 100, 0, 0),
        );
        let msgs = parse_events(&content);
        assert_eq!(msgs.len(), 2);
    }

    #[test]
    fn deduplicates_identical_records() {
        let resp = llm_response(
            "2026-01-15T10:00:05Z",
            "claude-sonnet-4-20250514",
            1000,
            200,
            0,
            0,
        );
        let content = format!(
            "{}\n{}\n{}\n",
            session_start("/home/user/project"),
            resp,
            resp,
        );
        let msgs = parse_events(&content);
        assert_eq!(msgs.len(), 1, "duplicate records should be collapsed");
    }

    #[test]
    fn timestampless_records_with_identical_usage_stay_distinct() {
        let content = format!(
            "{}\n{}\n{}\n",
            session_start("/home/user/project"),
            llm_response_without_timestamp("gpt-4o", 1200, 100, 50),
            llm_response_without_timestamp("gpt-4o", 3400, 100, 50),
        );
        let msgs = parse_events(&content);

        assert_eq!(msgs.len(), 2);
        assert_ne!(msgs[0].dedup_key, msgs[1].dedup_key);
        assert_eq!(msgs[0].duration_ms, Some(1200));
        assert_eq!(msgs[1].duration_ms, Some(3400));
    }

    #[test]
    fn reparsing_timestampless_records_reproduces_dedup_keys() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("test-session-123.jsonl");
        std::fs::write(
            &path,
            format!(
                "{}\n{}\n{}\n",
                session_start("/home/user/project"),
                llm_response_without_timestamp("gpt-4o", 1200, 100, 50),
                llm_response_without_timestamp("gpt-4o", 3400, 100, 50),
            ),
        )
        .unwrap();

        let parse_keys = || {
            parse_opencodereview_file(&path)
                .into_iter()
                .map(|msg| msg.dedup_key)
                .collect::<Vec<_>>()
        };
        let first = parse_keys();
        let second = parse_keys();

        assert_eq!(first.len(), 2);
        assert_eq!(first, second);
    }

    #[test]
    fn skips_zero_token_records() {
        let content = format!(
            "{}\n{}\n",
            session_start("/home/user/project"),
            llm_response(
                "2026-01-15T10:00:05Z",
                "claude-sonnet-4-20250514",
                0,
                0,
                0,
                0
            ),
        );
        let msgs = parse_events(&content);
        assert_eq!(msgs.len(), 0, "zero-token records should be skipped");
    }

    #[test]
    fn works_without_session_start() {
        let content = format!(
            "{}\n",
            llm_response(
                "2026-01-15T10:00:05Z",
                "claude-sonnet-4-20250514",
                1000,
                200,
                0,
                0
            ),
        );
        let msgs = parse_events(&content);
        assert_eq!(msgs.len(), 1);
        assert!(msgs[0].workspace_key.is_none());
    }

    #[test]
    fn session_id_derived_from_filename() {
        let dir = TempDir::new().unwrap();
        let path = dir.path().join("my-unique-session.jsonl");
        let content = llm_response("2026-01-15T10:00:05Z", "gpt-4o", 100, 50, 0, 0);
        std::fs::write(&path, format!("{content}\n")).unwrap();

        let msgs = parse_opencodereview_file(&path);
        assert_eq!(msgs.len(), 1);
        assert_eq!(msgs[0].session_id, "my-unique-session");
    }

    #[test]
    fn test_llm_response_timestamp_is_start_anchored() {
        // An `llm_response` record's
        // `timestamp` is written when the response is logged, i.e. the
        // call's *end*, not its start. `duration_ms` is that call's elapsed
        // time, so sessionize()'s `[timestamp, timestamp + duration_ms]`
        // span would otherwise project forward past the actual completion
        // into phantom idle time. The parser must back-calculate the start
        // anchor instead.
        let content = llm_response("2026-01-15T10:00:05Z", "gpt-4o", 100, 50, 0, 0);
        let msgs = parse_events(&format!("{content}\n"));

        assert_eq!(msgs.len(), 1);
        let expected_end =
            parse_timestamp_value(&Value::String("2026-01-15T10:00:05Z".to_string())).unwrap();
        assert_eq!(
            msgs[0].timestamp,
            expected_end - 1500,
            "timestamp must be back-calculated to the call start (end - duration)"
        );
        assert_eq!(
            msgs[0].duration_ms,
            Some(1500),
            "duration_ms must still span from start to the recorded end timestamp"
        );
    }
}