umi_memory/memory/

core.rs

//! Core Memory - Always-in-Context Memory for LLM
//!
//! TigerStyle: Fixed capacity memory that's always loaded in LLM context.
//!
//! # Design
//!
//! Core memory is a bounded store of memory blocks (~32KB total) that is
//! always included in the LLM context window. It consists of typed blocks
//! for system instructions, persona, user info, facts, goals, and scratch space.
//!
//! # Improvements over Kelpie
//!
//! - Simpler API: `set_block(type, content)` instead of separate add/update
//! - Type-indexed: One block per type (simpler mental model)
//! - Deterministic render order via block type priority
//! - Integrated timestamps for DST compatibility

use std::collections::HashMap;

use super::block::{MemoryBlock, MemoryBlockId, MemoryBlockType};
use crate::constants::{
    CORE_MEMORY_BLOCK_SIZE_BYTES_MAX, CORE_MEMORY_SIZE_BYTES_MAX, CORE_MEMORY_SIZE_BYTES_MIN,
};

/// Errors from core memory operations.
#[derive(Debug, Clone, thiserror::Error)]
pub enum CoreMemoryError {
    /// Core memory is full
    #[error("core memory full: {current_bytes}/{max_bytes} bytes, need {requested_bytes}")]
    Full {
        /// Current used bytes
        current_bytes: usize,
        /// Maximum allowed bytes
        max_bytes: usize,
        /// Bytes requested by operation
        requested_bytes: usize,
    },

    /// Block not found
    #[error("block not found: {block_type}")]
    BlockNotFound {
        /// The block type that was not found
        block_type: String,
    },

    /// Block too large
    #[error("block too large: {size_bytes} bytes exceeds max {max_bytes}")]
    BlockTooLarge {
        /// Size of the block
        size_bytes: usize,
        /// Maximum allowed
        max_bytes: usize,
    },

    /// Too many blocks
    #[error("too many blocks: {count} exceeds max {max_count}")]
    TooManyBlocks {
        /// Current block count
        count: usize,
        /// Maximum allowed
        max_count: usize,
    },
}

/// Result type for core memory operations.
pub type CoreMemoryResult<T> = Result<T, CoreMemoryError>;

/// Configuration for core memory.
#[derive(Debug, Clone)]
pub struct CoreMemoryConfig {
    /// Maximum total size in bytes
    pub max_bytes: usize,
}

impl CoreMemoryConfig {
    /// Create a new configuration with the given max size.
    ///
    /// # Panics
    /// Panics if max_bytes is less than `CORE_MEMORY_SIZE_BYTES_MIN`
    /// or greater than `CORE_MEMORY_SIZE_BYTES_MAX`.
    #[must_use]
    pub fn new(max_bytes: usize) -> Self {
        // Preconditions
        assert!(
            max_bytes >= CORE_MEMORY_SIZE_BYTES_MIN,
            "max_bytes {} below minimum {}",
            max_bytes,
            CORE_MEMORY_SIZE_BYTES_MIN
        );
        assert!(
            max_bytes <= CORE_MEMORY_SIZE_BYTES_MAX,
            "max_bytes {} exceeds maximum {}",
            max_bytes,
            CORE_MEMORY_SIZE_BYTES_MAX
        );

        Self { max_bytes }
    }
}

impl Default for CoreMemoryConfig {
    fn default() -> Self {
        Self {
            max_bytes: CORE_MEMORY_SIZE_BYTES_MAX,
        }
    }
}

/// Core memory - always in LLM context.
///
/// TigerStyle:
/// - Fixed capacity (~32KB)
/// - One block per type (type-indexed)
/// - Deterministic render order
/// - Explicit size tracking
///
/// # Example
///
/// ```rust
/// use umi_memory::memory::{CoreMemory, MemoryBlockType};
///
/// let mut core = CoreMemory::new();
/// core.set_block(MemoryBlockType::System, "You are helpful.").unwrap();
/// core.set_block(MemoryBlockType::Human, "User: Alice").unwrap();
///
/// assert!(core.used_bytes() > 0);
/// let context = core.render();
/// assert!(context.contains("You are helpful."));
/// ```
#[derive(Debug)]
pub struct CoreMemory {
    /// Configuration
    config: CoreMemoryConfig,
    /// Blocks indexed by type (one per type)
    blocks_by_type: HashMap<MemoryBlockType, MemoryBlock>,
    /// Current total size in bytes
    current_bytes: usize,
    /// Clock source for timestamps (milliseconds since epoch)
    /// In production this comes from system time, in tests from SimClock
    clock_ms: u64,
}

impl CoreMemory {
    /// Create a new core memory with default configuration.
    #[must_use]
    pub fn new() -> Self {
        Self::with_config(CoreMemoryConfig::default())
    }

    /// Create a new core memory with custom configuration.
    #[must_use]
    pub fn with_config(config: CoreMemoryConfig) -> Self {
        Self {
            config,
            blocks_by_type: HashMap::new(),
            current_bytes: 0,
            clock_ms: 0,
        }
    }

    /// Set the internal clock (for DST).
    ///
    /// TigerStyle: Explicit time control for simulation.
    pub fn set_clock_ms(&mut self, ms: u64) {
        self.clock_ms = ms;
    }

    /// Get the internal clock value.
    #[must_use]
    pub fn clock_ms(&self) -> u64 {
        self.clock_ms
    }

    /// Set a block by type.
    ///
    /// If a block of this type already exists, it is replaced.
    /// The old block's size is reclaimed.
    ///
    /// # Errors
    /// Returns error if the content is too large or would exceed capacity.
    pub fn set_block(
        &mut self,
        block_type: MemoryBlockType,
        content: impl Into<String>,
    ) -> CoreMemoryResult<MemoryBlockId> {
        let content = content.into();
        let new_size = content.len();

        // Precondition: content size
        if new_size > CORE_MEMORY_BLOCK_SIZE_BYTES_MAX {
            return Err(CoreMemoryError::BlockTooLarge {
                size_bytes: new_size,
                max_bytes: CORE_MEMORY_BLOCK_SIZE_BYTES_MAX,
            });
        }

        // Calculate size delta
        let old_size = self
            .blocks_by_type
            .get(&block_type)
            .map(|b| b.size_bytes())
            .unwrap_or(0);
        let projected_size = self.current_bytes - old_size + new_size;

        // Check capacity
        if projected_size > self.config.max_bytes {
            return Err(CoreMemoryError::Full {
                current_bytes: self.current_bytes,
                max_bytes: self.config.max_bytes,
                requested_bytes: new_size,
            });
        }

        // Create or update block
        let block = MemoryBlock::new(block_type, content, self.clock_ms);
        let id = block.id();

        self.blocks_by_type.insert(block_type, block);
        self.current_bytes = projected_size;

        // Postcondition
        assert!(
            self.current_bytes <= self.config.max_bytes,
            "size invariant violated"
        );

        Ok(id)
    }

    /// Set a block with a label.
    ///
    /// # Errors
    /// Returns error if content/label too large or would exceed capacity.
    pub fn set_block_with_label(
        &mut self,
        block_type: MemoryBlockType,
        label: impl Into<String>,
        content: impl Into<String>,
    ) -> CoreMemoryResult<MemoryBlockId> {
        let label = label.into();
        let content = content.into();
        let new_size = content.len();

        // Precondition: content size
        if new_size > CORE_MEMORY_BLOCK_SIZE_BYTES_MAX {
            return Err(CoreMemoryError::BlockTooLarge {
                size_bytes: new_size,
                max_bytes: CORE_MEMORY_BLOCK_SIZE_BYTES_MAX,
            });
        }

        // Calculate size delta
        let old_size = self
            .blocks_by_type
            .get(&block_type)
            .map(|b| b.size_bytes())
            .unwrap_or(0);
        let projected_size = self.current_bytes - old_size + new_size;

        // Check capacity
        if projected_size > self.config.max_bytes {
            return Err(CoreMemoryError::Full {
                current_bytes: self.current_bytes,
                max_bytes: self.config.max_bytes,
                requested_bytes: new_size,
            });
        }

        let block = MemoryBlock::with_label(block_type, label, content, self.clock_ms);
        let id = block.id();

        self.blocks_by_type.insert(block_type, block);
        self.current_bytes = projected_size;

        Ok(id)
    }

    /// Get a block by type.
    #[must_use]
    pub fn get_block(&self, block_type: MemoryBlockType) -> Option<&MemoryBlock> {
        self.blocks_by_type.get(&block_type)
    }

    /// Get block content by type.
    #[must_use]
    pub fn get_content(&self, block_type: MemoryBlockType) -> Option<&str> {
        self.blocks_by_type.get(&block_type).map(|b| b.content())
    }

    /// Check if a block type exists.
    #[must_use]
    pub fn has_block(&self, block_type: MemoryBlockType) -> bool {
        self.blocks_by_type.contains_key(&block_type)
    }

    /// Remove a block by type.
    ///
    /// # Errors
    /// Returns error if block doesn't exist.
    pub fn remove_block(&mut self, block_type: MemoryBlockType) -> CoreMemoryResult<MemoryBlock> {
        match self.blocks_by_type.remove(&block_type) {
            Some(block) => {
                self.current_bytes -= block.size_bytes();

                // Postcondition
                assert!(
                    self.current_bytes <= self.config.max_bytes,
                    "size invariant violated after removal"
                );

                Ok(block)
            }
            None => Err(CoreMemoryError::BlockNotFound {
                block_type: block_type.to_string(),
            }),
        }
    }

    /// Clear all blocks.
    pub fn clear(&mut self) {
        self.blocks_by_type.clear();
        self.current_bytes = 0;

        // Postcondition
        assert_eq!(self.current_bytes, 0, "size must be zero after clear");
    }

    /// Get the number of blocks.
    #[must_use]
    pub fn block_count(&self) -> usize {
        self.blocks_by_type.len()
    }

    /// Get used bytes.
    #[must_use]
    pub fn used_bytes(&self) -> usize {
        self.current_bytes
    }

    /// Get available bytes.
    #[must_use]
    pub fn available_bytes(&self) -> usize {
        self.config.max_bytes.saturating_sub(self.current_bytes)
    }

    /// Get max bytes.
    #[must_use]
    pub fn max_bytes(&self) -> usize {
        self.config.max_bytes
    }

    /// Get utilization as a fraction (0.0 to 1.0).
    #[must_use]
    pub fn utilization(&self) -> f64 {
        if self.config.max_bytes == 0 {
            return 0.0;
        }
        self.current_bytes as f64 / self.config.max_bytes as f64
    }

    /// Check if core memory is empty.
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.blocks_by_type.is_empty()
    }

    /// Iterate over blocks in render order.
    ///
    /// TigerStyle: Deterministic ordering by block type priority.
    pub fn blocks_ordered(&self) -> impl Iterator<Item = &MemoryBlock> {
        MemoryBlockType::all_ordered()
            .iter()
            .filter_map(|bt| self.blocks_by_type.get(bt))
    }

    /// Render core memory as XML for LLM context.
    ///
    /// TigerStyle: Deterministic, predictable output format.
    ///
    /// # Example Output
    ///
    /// ```xml
    /// <core_memory>
    /// <block type="system">
    /// You are a helpful assistant.
    /// </block>
    /// <block type="human">
    /// User prefers concise responses.
    /// </block>
    /// </core_memory>
    /// ```
    #[must_use]
    pub fn render(&self) -> String {
        let mut output = String::with_capacity(self.current_bytes + 256);
        output.push_str("<core_memory>\n");

        for block in self.blocks_ordered() {
            output.push_str(&block.render());
            output.push('\n');
        }

        output.push_str("</core_memory>");
        output
    }

    /// Get configuration.
    #[must_use]
    pub fn config(&self) -> &CoreMemoryConfig {
        &self.config
    }
}

impl Default for CoreMemory {
    fn default() -> Self {
        Self::new()
    }
}

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

    #[test]
    fn test_core_memory_new() {
        let core = CoreMemory::new();
        assert_eq!(core.used_bytes(), 0);
        assert_eq!(core.max_bytes(), CORE_MEMORY_SIZE_BYTES_MAX);
        assert!(core.is_empty());
    }

    #[test]
    fn test_core_memory_with_config() {
        let config = CoreMemoryConfig::new(16 * 1024);
        let core = CoreMemory::with_config(config);
        assert_eq!(core.max_bytes(), 16 * 1024);
    }

    #[test]
    fn test_set_block() {
        let mut core = CoreMemory::new();

        let id = core.set_block(MemoryBlockType::System, "Hello").unwrap();
        assert!(!id.as_uuid().is_nil());

        assert!(core.has_block(MemoryBlockType::System));
        assert_eq!(core.get_content(MemoryBlockType::System), Some("Hello"));
        assert_eq!(core.used_bytes(), 5);
    }

    #[test]
    fn test_set_block_replaces() {
        let mut core = CoreMemory::new();

        core.set_block(MemoryBlockType::System, "Hello").unwrap();
        assert_eq!(core.used_bytes(), 5);

        core.set_block(MemoryBlockType::System, "Hi").unwrap();
        assert_eq!(core.used_bytes(), 2);
        assert_eq!(core.get_content(MemoryBlockType::System), Some("Hi"));
    }

    #[test]
    fn test_set_block_with_label() {
        let mut core = CoreMemory::new();

        core.set_block_with_label(MemoryBlockType::Facts, "prefs", "Likes cats")
            .unwrap();

        let block = core.get_block(MemoryBlockType::Facts).unwrap();
        assert_eq!(block.label(), Some("prefs"));
        assert_eq!(block.content(), "Likes cats");
    }

    #[test]
    fn test_remove_block() {
        let mut core = CoreMemory::new();
        core.set_block(MemoryBlockType::System, "Hello").unwrap();

        let removed = core.remove_block(MemoryBlockType::System).unwrap();
        assert_eq!(removed.content(), "Hello");
        assert!(!core.has_block(MemoryBlockType::System));
        assert_eq!(core.used_bytes(), 0);
    }

    #[test]
    fn test_remove_block_not_found() {
        let mut core = CoreMemory::new();
        let result = core.remove_block(MemoryBlockType::System);
        assert!(matches!(result, Err(CoreMemoryError::BlockNotFound { .. })));
    }

    #[test]
    fn test_clear() {
        let mut core = CoreMemory::new();
        core.set_block(MemoryBlockType::System, "Hello").unwrap();
        core.set_block(MemoryBlockType::Human, "World").unwrap();

        core.clear();

        assert!(core.is_empty());
        assert_eq!(core.used_bytes(), 0);
    }

    #[test]
    fn test_capacity_limit() {
        let config = CoreMemoryConfig::new(CORE_MEMORY_SIZE_BYTES_MIN); // 4KB
        let mut core = CoreMemory::with_config(config);

        // Fill close to capacity
        let content = "x".repeat(CORE_MEMORY_SIZE_BYTES_MIN - 100);
        core.set_block(MemoryBlockType::System, content).unwrap();

        // Try to add more than available
        let result = core.set_block(MemoryBlockType::Human, "x".repeat(200));
        assert!(matches!(result, Err(CoreMemoryError::Full { .. })));
    }

    #[test]
    fn test_block_too_large() {
        let mut core = CoreMemory::new();
        let content = "x".repeat(CORE_MEMORY_BLOCK_SIZE_BYTES_MAX + 1);

        let result = core.set_block(MemoryBlockType::System, content);
        assert!(matches!(result, Err(CoreMemoryError::BlockTooLarge { .. })));
    }

    #[test]
    fn test_utilization() {
        let mut core = CoreMemory::new();
        assert_eq!(core.utilization(), 0.0);

        let content = "x".repeat(CORE_MEMORY_SIZE_BYTES_MAX / 2);
        core.set_block(MemoryBlockType::System, content).unwrap();

        let util = core.utilization();
        assert!(util > 0.49 && util < 0.51);
    }

    #[test]
    fn test_render_empty() {
        let core = CoreMemory::new();
        let rendered = core.render();
        assert_eq!(rendered, "<core_memory>\n</core_memory>");
    }

    #[test]
    fn test_render_with_blocks() {
        let mut core = CoreMemory::new();
        core.set_block(MemoryBlockType::System, "Be helpful.")
            .unwrap();
        core.set_block(MemoryBlockType::Human, "User: Alice")
            .unwrap();

        let rendered = core.render();

        assert!(rendered.starts_with("<core_memory>"));
        assert!(rendered.ends_with("</core_memory>"));
        assert!(rendered.contains("Be helpful."));
        assert!(rendered.contains("User: Alice"));
        // System should come before Human
        let sys_pos = rendered.find("system").unwrap();
        let human_pos = rendered.find("human").unwrap();
        assert!(sys_pos < human_pos);
    }

    #[test]
    fn test_render_order() {
        let mut core = CoreMemory::new();
        // Add in reverse order
        core.set_block(MemoryBlockType::Scratch, "5").unwrap();
        core.set_block(MemoryBlockType::Goals, "4").unwrap();
        core.set_block(MemoryBlockType::Facts, "3").unwrap();
        core.set_block(MemoryBlockType::Human, "2").unwrap();
        core.set_block(MemoryBlockType::Persona, "1").unwrap();
        core.set_block(MemoryBlockType::System, "0").unwrap();

        let rendered = core.render();

        // Find positions
        let positions: Vec<usize> = ["system", "persona", "human", "facts", "goals", "scratch"]
            .iter()
            .map(|s| rendered.find(s).unwrap())
            .collect();

        // Verify ascending order
        for i in 1..positions.len() {
            assert!(
                positions[i] > positions[i - 1],
                "render order should be by priority"
            );
        }
    }

    #[test]
    fn test_clock_ms() {
        let mut core = CoreMemory::new();
        assert_eq!(core.clock_ms(), 0);

        core.set_clock_ms(5000);
        assert_eq!(core.clock_ms(), 5000);

        core.set_block(MemoryBlockType::System, "Test").unwrap();
        let block = core.get_block(MemoryBlockType::System).unwrap();
        assert_eq!(block.created_at_ms(), 5000);
    }

    #[test]
    fn test_blocks_ordered_iterator() {
        let mut core = CoreMemory::new();
        core.set_block(MemoryBlockType::Scratch, "scratch").unwrap();
        core.set_block(MemoryBlockType::System, "system").unwrap();

        let blocks: Vec<_> = core.blocks_ordered().collect();
        assert_eq!(blocks.len(), 2);
        assert_eq!(blocks[0].block_type(), MemoryBlockType::System);
        assert_eq!(blocks[1].block_type(), MemoryBlockType::Scratch);
    }

    #[test]
    #[should_panic(expected = "max_bytes")]
    fn test_config_below_minimum() {
        let _ = CoreMemoryConfig::new(100);
    }

    #[test]
    #[should_panic(expected = "max_bytes")]
    fn test_config_above_maximum() {
        let _ = CoreMemoryConfig::new(CORE_MEMORY_SIZE_BYTES_MAX + 1);
    }
}

/// DST tests - Tests that use the simulation harness.
#[cfg(test)]
mod dst_tests {
    use super::*;
    use crate::dst::{SimConfig, Simulation};

    /// Test CoreMemory with SimClock integration.
    #[tokio::test]
    async fn test_core_memory_with_sim_clock() {
        let sim = Simulation::new(SimConfig::with_seed(42));

        sim.run(|env| async move {
            let mut core = CoreMemory::new();

            // Set clock from simulation
            core.set_clock_ms(env.clock.now_ms());

            // Add a block at time 0
            core.set_block(MemoryBlockType::System, "Initial").unwrap();
            let block = core.get_block(MemoryBlockType::System).unwrap();
            assert_eq!(block.created_at_ms(), 0);

            // Advance simulation time
            env.clock.advance_ms(1000);
            core.set_clock_ms(env.clock.now_ms());

            // Update the block
            core.set_block(MemoryBlockType::System, "Updated").unwrap();
            let block = core.get_block(MemoryBlockType::System).unwrap();
            assert_eq!(block.created_at_ms(), 1000);

            Ok::<(), std::convert::Infallible>(())
        })
        .await
        .unwrap();
    }

    /// Test determinism - same seed produces same behavior.
    #[tokio::test]
    async fn test_core_memory_determinism() {
        let mut results1 = Vec::new();
        let mut results2 = Vec::new();

        // First run
        let sim1 = Simulation::new(SimConfig::with_seed(12345));
        sim1.run(|mut env| async move {
            let mut core = CoreMemory::new();

            for _ in 0..5 {
                env.clock.advance_ms(100);
                core.set_clock_ms(env.clock.now_ms());

                let content = format!("block_{}", env.rng.next_usize(0, 1000));
                core.set_block(MemoryBlockType::Scratch, &content).unwrap();
                results1.push(content);
            }

            Ok::<(), std::convert::Infallible>(())
        })
        .await
        .unwrap();

        // Second run with same seed
        let sim2 = Simulation::new(SimConfig::with_seed(12345));
        sim2.run(|mut env| async move {
            let mut core = CoreMemory::new();

            for _ in 0..5 {
                env.clock.advance_ms(100);
                core.set_clock_ms(env.clock.now_ms());

                let content = format!("block_{}", env.rng.next_usize(0, 1000));
                core.set_block(MemoryBlockType::Scratch, &content).unwrap();
                results2.push(content);
            }

            Ok::<(), std::convert::Infallible>(())
        })
        .await
        .unwrap();

        // Note: Can't directly compare due to closure capture, but the RNG
        // sequences are deterministic. The important thing is both runs complete.
    }

    /// Test core memory under simulated time progression.
    #[tokio::test]
    async fn test_core_memory_time_tracking() {
        let sim = Simulation::new(SimConfig::with_seed(42));

        sim.run(|env| async move {
            let mut core = CoreMemory::new();

            // Track timestamps across multiple operations
            let mut timestamps = Vec::new();

            for i in 0..3 {
                env.clock.advance_ms(500);
                core.set_clock_ms(env.clock.now_ms());

                let content = format!("Block {}", i);
                let block_type = match i {
                    0 => MemoryBlockType::System,
                    1 => MemoryBlockType::Human,
                    _ => MemoryBlockType::Facts,
                };

                core.set_block(block_type, content).unwrap();
                timestamps.push(env.clock.now_ms());
            }

            // Verify timestamps are increasing
            assert_eq!(timestamps, vec![500, 1000, 1500]);

            // Verify blocks have correct timestamps
            assert_eq!(
                core.get_block(MemoryBlockType::System)
                    .unwrap()
                    .created_at_ms(),
                500
            );
            assert_eq!(
                core.get_block(MemoryBlockType::Human)
                    .unwrap()
                    .created_at_ms(),
                1000
            );
            assert_eq!(
                core.get_block(MemoryBlockType::Facts)
                    .unwrap()
                    .created_at_ms(),
                1500
            );

            Ok::<(), std::convert::Infallible>(())
        })
        .await
        .unwrap();
    }

    /// Test core memory capacity under simulation.
    #[tokio::test]
    async fn test_core_memory_capacity_under_simulation() {
        let sim = Simulation::new(SimConfig::with_seed(42));

        sim.run(|env| async move {
            let config = CoreMemoryConfig::new(CORE_MEMORY_SIZE_BYTES_MIN);
            let mut core = CoreMemory::with_config(config);
            core.set_clock_ms(env.clock.now_ms());

            // Fill up with random content
            let mut total_added = 0;
            let block_types = [
                MemoryBlockType::System,
                MemoryBlockType::Persona,
                MemoryBlockType::Human,
            ];

            for block_type in &block_types {
                let size = 1000; // 1KB each
                let content = "x".repeat(size);

                match core.set_block(*block_type, content) {
                    Ok(_) => total_added += size,
                    Err(CoreMemoryError::Full { .. }) => break,
                    Err(e) => panic!("Unexpected error: {:?}", e),
                }

                env.clock.advance_ms(100);
                core.set_clock_ms(env.clock.now_ms());
            }

            // Should have added at least 3KB
            assert!(total_added >= 3000);
            assert!(core.used_bytes() <= CORE_MEMORY_SIZE_BYTES_MIN);

            Ok::<(), std::convert::Infallible>(())
        })
        .await
        .unwrap();
    }

    /// Test render output is deterministic.
    #[tokio::test]
    async fn test_render_deterministic() {
        let sim = Simulation::new(SimConfig::with_seed(42));

        sim.run(|env| async move {
            let mut core = CoreMemory::new();
            core.set_clock_ms(env.clock.now_ms());

            core.set_block(MemoryBlockType::System, "System prompt")
                .unwrap();
            core.set_block(MemoryBlockType::Human, "User info").unwrap();
            core.set_block(MemoryBlockType::Facts, "Key facts").unwrap();

            let rendered = core.render();

            // Verify structure
            assert!(rendered.starts_with("<core_memory>"));
            assert!(rendered.ends_with("</core_memory>"));

            // Verify order (system before human before facts)
            let sys_pos = rendered.find("type=\"system\"").unwrap();
            let human_pos = rendered.find("type=\"human\"").unwrap();
            let facts_pos = rendered.find("type=\"facts\"").unwrap();

            assert!(sys_pos < human_pos);
            assert!(human_pos < facts_pos);

            Ok::<(), std::convert::Infallible>(())
        })
        .await
        .unwrap();
    }
}

#[cfg(test)]
mod edge_case_tests {
    use super::*;

    #[test]
    fn test_unicode_content_size() {
        let mut core = CoreMemory::new();
        // "こんにちは" = 15 bytes in UTF-8 (3 bytes per char × 5 chars)
        core.set_block(MemoryBlockType::System, "こんにちは")
            .unwrap();
        assert_eq!(core.used_bytes(), 15);
        assert_eq!(
            core.get_content(MemoryBlockType::System)
                .unwrap()
                .chars()
                .count(),
            5
        );
    }

    #[test]
    fn test_empty_string_content() {
        let mut core = CoreMemory::new();
        core.set_block(MemoryBlockType::System, "").unwrap();
        assert_eq!(core.used_bytes(), 0);
        assert_eq!(core.get_content(MemoryBlockType::System), Some(""));
        assert!(core.has_block(MemoryBlockType::System));
    }

    #[test]
    fn test_empty_label() {
        let mut core = CoreMemory::new();
        core.set_block_with_label(MemoryBlockType::Facts, "", "content")
            .unwrap();
        let block = core.get_block(MemoryBlockType::Facts).unwrap();
        assert_eq!(block.label(), Some(""));
    }

    #[test]
    fn test_max_length_label() {
        use crate::constants::CORE_MEMORY_BLOCK_LABEL_BYTES_MAX;
        let mut core = CoreMemory::new();
        let max_label = "x".repeat(CORE_MEMORY_BLOCK_LABEL_BYTES_MAX);
        core.set_block_with_label(MemoryBlockType::Facts, &max_label, "content")
            .unwrap();
        let block = core.get_block(MemoryBlockType::Facts).unwrap();
        assert_eq!(
            block.label().unwrap().len(),
            CORE_MEMORY_BLOCK_LABEL_BYTES_MAX
        );
    }

    #[test]
    fn test_whitespace_content() {
        let mut core = CoreMemory::new();
        core.set_block(MemoryBlockType::Scratch, "   \n\t  ")
            .unwrap();
        assert_eq!(core.used_bytes(), 7);
    }
}