move journal types from agent/journal.rs to thought/context.rs

JournalEntry, parse_journal, parse_journal_text, parse_header_timestamp,
and default_journal_path consolidated into thought/context.rs. Delete
the duplicate agent/journal.rs (235 lines). Update all references.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

src/thought/context.rs

@@ -5,10 +5,82 @@
 // take inputs and return new values. State mutation happens in agent.rs.
 
 // TODO: move Message, ContextState, etc. to thought layer
-use crate::agent::journal;
 use crate::agent::types::*;
-use chrono::{DateTime, Utc};
+use chrono::{DateTime, NaiveDateTime, Utc};
 use tiktoken_rs::CoreBPE;
+use std::path::Path;
+
+/// A single journal entry with its timestamp and content.
+#[derive(Debug, Clone)]
+pub struct JournalEntry {
+    pub timestamp: DateTime<Utc>,
+    pub content: String,
+}
+
+/// Parse journal entries from the journal file. Returns entries sorted
+/// by timestamp (oldest first). Entries with unparseable timestamps
+/// are skipped.
+pub fn parse_journal(path: &Path) -> Vec<JournalEntry> {
+    let text = match std::fs::read_to_string(path) {
+        Ok(t) => t,
+        Err(_) => return Vec::new(),
+    };
+    parse_journal_text(&text)
+}
+
+/// Parse journal entries from text.
+pub fn parse_journal_text(text: &str) -> Vec<JournalEntry> {
+    let mut entries = Vec::new();
+    let mut current_timestamp: Option<DateTime<Utc>> = None;
+    let mut current_content = String::new();
+
+    for line in text.lines() {
+        if let Some(ts) = parse_header_timestamp(line) {
+            if let Some(prev_ts) = current_timestamp.take() {
+                let content = current_content.trim().to_string();
+                if !content.is_empty() {
+                    entries.push(JournalEntry { timestamp: prev_ts, content });
+                }
+            }
+            current_timestamp = Some(ts);
+            current_content.clear();
+        } else if current_timestamp.is_some() {
+            current_content.push_str(line);
+            current_content.push('\n');
+        }
+    }
+
+    if let Some(ts) = current_timestamp {
+        let content = current_content.trim().to_string();
+        if !content.is_empty() {
+            entries.push(JournalEntry { timestamp: ts, content });
+        }
+    }
+
+    entries
+}
+
+/// Try to parse a line as a journal header (## TIMESTAMP [— title]).
+fn parse_header_timestamp(line: &str) -> Option<DateTime<Utc>> {
+    let line = line.trim();
+    if !line.starts_with("## ") { return None; }
+    let rest = line[3..].trim();
+    if !rest.starts_with(|c: char| c.is_ascii_digit()) { return None; }
+    let ts_str = rest.split_once(' ').map_or(rest, |(ts, _)| ts);
+    for fmt in ["%Y-%m-%dT%H:%M:%S", "%Y-%m-%dT%H:%M"] {
+        if let Ok(naive) = NaiveDateTime::parse_from_str(ts_str, fmt) {
+            return Some(naive.and_utc());
+        }
+    }
+    None
+}
+
+/// Default journal file path.
+pub fn default_journal_path() -> std::path::PathBuf {
+    dirs::home_dir()
+        .unwrap_or_default()
+        .join(".consciousness/journal.md")
+}
 
 /// Look up a model's context window size in tokens.
 pub fn model_context_window(_model: &str) -> usize {
@@ -47,8 +119,8 @@ pub fn build_context_window(
     model: &str,
     tokenizer: &CoreBPE,
 ) -> (Vec<Message>, String) {
-    let journal_path = journal::default_journal_path();
-    let all_entries = journal::parse_journal(&journal_path);
+    let journal_path = default_journal_path();
+    let all_entries = parse_journal(&journal_path);
     dbglog!("[ctx] {} journal entries from {}", all_entries.len(), journal_path.display());
     let count = |s: &str| tokenizer.encode_with_special_tokens(s).len();
 
@@ -96,7 +168,7 @@ pub fn plan_context(
     system_prompt: &str,
     context_message: &str,
     recent: &[Message],
-    entries: &[journal::JournalEntry],
+    entries: &[JournalEntry],
     model: &str,
     count: &dyn Fn(&str) -> usize,
 ) -> ContextPlan {
@@ -184,7 +256,7 @@ pub fn plan_context(
 }
 
 pub fn render_journal_text(
-    entries: &[journal::JournalEntry],
+    entries: &[JournalEntry],
     plan: &ContextPlan,
 ) -> String {
     let has_journal = plan.header_start < plan.entry_count;
@@ -285,7 +357,7 @@ fn truncate_at_section(text: &str, max_tokens: usize, count: &dyn Fn(&str) -> us
 
 fn find_journal_cutoff(
     conversation: &[Message],
-    newest_entry: Option<&journal::JournalEntry>,
+    newest_entry: Option<&JournalEntry>,
 ) -> usize {
     let cutoff = match newest_entry {
         Some(entry) => entry.timestamp,

src/thought/journal.rs

@@ -44,7 +44,7 @@ pub fn write_entry(args: &serde_json::Value) -> Result<String> {
         .as_str()
         .context("entry is required")?;
 
-    let journal_path = crate::agent::journal::default_journal_path();
+    let journal_path = crate::thought::context::default_journal_path();
 
     // Ensure parent directory exists
     if let Some(parent) = journal_path.parent() {