codewhale/crates/tui/src/core/engine/tests.rs

use super::*;

use serde_json::json;
use std::fs;
use std::path::PathBuf;
use std::time::Instant;
use tempfile::tempdir;

fn build_engine_with_capacity(capacity: CapacityControllerConfig) -> Engine {
    let engine_config = EngineConfig {
        capacity,
        ..Default::default()
    };
    let (engine, _handle) = Engine::new(engine_config, &Config::default());
    engine
}

fn make_plan(
    read_only: bool,
    supports_parallel: bool,
    approval_required: bool,
    interactive: bool,
) -> ToolExecutionPlan {
    ToolExecutionPlan {
        index: 0,
        id: "tool-1".to_string(),
        name: "grep_files".to_string(),
        input: json!({"pattern": "test"}),
        caller: None,
        interactive,
        approval_required,
        approval_description: "desc".to_string(),
        supports_parallel,
        read_only,
        blocked_error: None,
    }
}

#[test]
fn engine_handle_cancel_tracks_latest_turn_token() {
    let (mut engine, handle) = Engine::new(EngineConfig::default(), &Config::default());
    let stale_token = engine.cancel_token.clone();

    engine.reset_cancel_token();
    handle.cancel();

    assert!(engine.cancel_token.is_cancelled());
    assert!(handle.is_cancelled());
    assert!(!stale_token.is_cancelled());
}

#[test]
fn parallel_batch_requires_read_only_parallel_tools() {
    let plans = vec![make_plan(true, true, false, false)];
    assert!(should_parallelize_tool_batch(&plans));

    let plans = vec![
        make_plan(true, true, false, false),
        make_plan(true, true, false, false),
    ];
    assert!(should_parallelize_tool_batch(&plans));

    let plans = vec![make_plan(false, true, false, false)];
    assert!(!should_parallelize_tool_batch(&plans));

    let plans = vec![make_plan(true, false, false, false)];
    assert!(!should_parallelize_tool_batch(&plans));

    let plans = vec![make_plan(true, true, true, false)];
    assert!(!should_parallelize_tool_batch(&plans));

    let plans = vec![make_plan(true, true, false, true)];
    assert!(!should_parallelize_tool_batch(&plans));
}

#[test]
fn successful_update_plan_ends_plan_mode_turn_immediately() {
    assert!(should_stop_after_plan_tool(
        AppMode::Plan,
        "update_plan",
        &Ok(ToolResult::success("planned"))
    ));
    assert!(!should_stop_after_plan_tool(
        AppMode::Agent,
        "update_plan",
        &Ok(ToolResult::success("planned"))
    ));
    assert!(!should_stop_after_plan_tool(
        AppMode::Plan,
        "request_user_input",
        &Ok(ToolResult::success("input"))
    ));
    assert!(!should_stop_after_plan_tool(
        AppMode::Plan,
        "update_plan",
        &Err(ToolError::execution_failed("failed".to_string()))
    ));
}

#[test]
fn quick_plan_requests_force_update_plan_on_first_step() {
    assert!(should_force_update_plan_first(
        AppMode::Plan,
        "Give me a quick 3-step plan to verify the UI changes."
    ));
    assert!(should_force_update_plan_first(
        AppMode::Plan,
        "Make a high-level plan for the footer work."
    ));
    assert!(!should_force_update_plan_first(
        AppMode::Plan,
        "Inspect the repo and then give me a quick plan."
    ));
    assert!(!should_force_update_plan_first(
        AppMode::Agent,
        "Give me a quick 3-step plan."
    ));
}

#[test]
fn quick_plan_turn_can_narrow_first_step_tools_to_update_plan() {
    let catalog = vec![
        Tool {
            tool_type: Some("function".to_string()),
            name: "read_file".to_string(),
            description: "Read a file".to_string(),
            input_schema: json!({"type": "object"}),
            allowed_callers: Some(vec!["direct".to_string()]),
            defer_loading: Some(false),
            input_examples: None,
            strict: None,
            cache_control: None,
        },
        Tool {
            tool_type: Some("function".to_string()),
            name: "update_plan".to_string(),
            description: "Publish a plan".to_string(),
            input_schema: json!({"type": "object"}),
            allowed_callers: Some(vec!["direct".to_string()]),
            defer_loading: Some(false),
            input_examples: None,
            strict: None,
            cache_control: None,
        },
    ];
    let active = initial_active_tools(&catalog);

    let forced = active_tools_for_step(&catalog, &active, true);
    assert_eq!(forced.len(), 1);
    assert_eq!(forced[0].name, "update_plan");

    let default = active_tools_for_step(&catalog, &active, false);
    assert_eq!(default.len(), 2);
}

#[test]
fn tool_error_messages_include_actionable_hints() {
    let path_error = ToolError::path_escape(PathBuf::from("../escape.txt"));
    let formatted = format_tool_error(&path_error, "read_file");
    assert!(formatted.contains("escapes workspace"));

    let missing_field = ToolError::missing_field("path");
    let formatted = format_tool_error(&missing_field, "read_file");
    assert!(formatted.contains("missing required field"));

    let timeout = ToolError::Timeout { seconds: 5 };
    let formatted = format_tool_error(&timeout, "exec_shell");
    assert!(formatted.contains("timed out"));
}

#[test]
fn tool_exec_outcome_tracks_duration() {
    let outcome = ToolExecOutcome {
        index: 0,
        id: "tool-1".to_string(),
        name: "grep_files".to_string(),
        input: json!({"pattern": "test"}),
        started_at: Instant::now(),
        result: Ok(ToolResult::success("ok")),
    };

    assert!(outcome.started_at.elapsed().as_nanos() > 0);
}

#[test]
fn yolo_mode_keeps_tools_preloaded() {
    assert!(!should_default_defer_tool("exec_shell", AppMode::Yolo));
    assert!(!should_default_defer_tool(
        "mcp_read_resource",
        AppMode::Yolo
    ));
}

#[test]
fn non_yolo_mode_retains_default_defer_policy() {
    // Shell tools are kept loaded in action modes so the model can verify
    // work without an extra ToolSearch round-trip; non-action tools (e.g.
    // MCP) still defer.
    assert!(!should_default_defer_tool("exec_shell", AppMode::Agent));
    assert!(should_default_defer_tool("exec_shell", AppMode::Plan));
    assert!(!should_default_defer_tool("read_file", AppMode::Agent));
    assert!(should_default_defer_tool(
        "mcp_read_resource",
        AppMode::Agent
    ));
}

#[test]
fn agent_mode_can_build_auto_approved_tool_context() {
    let (engine, _handle) = Engine::new(EngineConfig::default(), &Config::default());

    assert!(
        !engine
            .build_tool_context(AppMode::Agent, false)
            .auto_approve
    );
    assert!(engine.build_tool_context(AppMode::Agent, true).auto_approve);
    assert!(engine.build_tool_context(AppMode::Yolo, false).auto_approve);
}

#[tokio::test]
async fn session_update_preserves_reasoning_tool_only_turn() {
    let (mut engine, handle) = Engine::new(EngineConfig::default(), &Config::default());
    let assistant = Message {
        role: "assistant".to_string(),
        content: vec![
            ContentBlock::Thinking {
                thinking: "Need a tool before answering.".to_string(),
            },
            ContentBlock::ToolUse {
                id: "tool-1".to_string(),
                name: "read_file".to_string(),
                input: json!({"path": "Cargo.toml"}),
                caller: None,
            },
        ],
    };

    engine.add_session_message(assistant.clone()).await;

    let event = {
        let mut rx = handle.rx_event.write().await;
        rx.recv().await.expect("session update event")
    };
    let Event::SessionUpdated { messages, .. } = event else {
        panic!("expected session update event");
    };

    assert_eq!(messages, vec![assistant]);
}

#[test]
fn detects_context_length_errors_from_provider_payloads() {
    let msg = r#"SSE stream request failed: HTTP 400 Bad Request: {"error":{"message":"This model's maximum context length is 131072 tokens. However, you requested 153056 tokens (148960 in the messages, 4096 in the completion).","type":"invalid_request_error"}}"#;
    assert!(is_context_length_error_message(msg));
    assert!(!is_context_length_error_message(
        "SSE stream request failed: HTTP 400 Bad Request: model not found"
    ));
}

#[test]
fn context_budget_reserves_output_and_headroom() {
    // V4 has a 1M context window — the only family that comfortably hosts
    // a 256K output reservation without saturating the input budget to 0.
    let budget = context_input_budget("deepseek-v4-pro", TURN_MAX_OUTPUT_TOKENS)
        .expect("deepseek-v4-pro should have a known context window");
    let v4_window: usize = 1_000_000;
    let expected = v4_window - (TURN_MAX_OUTPUT_TOKENS as usize) - 1_024usize;
    assert_eq!(budget, expected);
}

#[test]
fn v4_tool_outputs_keep_large_file_reads_in_context() {
    let content = "0123456789abcdef\n".repeat(2_000);
    let output = ToolResult::success(content.clone());

    let v4_context = compact_tool_result_for_context("deepseek-v4-pro", "exec_shell", &output);
    assert_eq!(v4_context, content.trim());

    let legacy_context =
        compact_tool_result_for_context("deepseek-v3.2-128k", "exec_shell", &output);
    assert!(legacy_context.contains("output compacted to protect context"));
    assert!(legacy_context.len() < v4_context.len());
}

#[test]
fn refresh_system_prompt_places_working_set_after_stable_prefix() {
    let tmp = tempdir().expect("tempdir");
    fs::create_dir_all(tmp.path().join("src")).expect("mkdir");
    fs::write(tmp.path().join("src/lib.rs"), "pub fn sample() {}").expect("write");

    let config = EngineConfig {
        workspace: tmp.path().to_path_buf(),
        ..Default::default()
    };
    let (mut engine, _handle) = Engine::new(config, &Config::default());
    engine
        .session
        .working_set
        .observe_user_message("please inspect src/lib.rs", tmp.path());

    engine.refresh_system_prompt(AppMode::Agent);

    let Some(SystemPrompt::Blocks(blocks)) = &engine.session.system_prompt else {
        panic!("expected structured prompt blocks");
    };
    let last = blocks.last().expect("working-set block");
    assert!(last.text.contains(WORKING_SET_SUMMARY_MARKER));
    assert!(
        blocks[..blocks.len() - 1]
            .iter()
            .all(|block| !block.text.contains(WORKING_SET_SUMMARY_MARKER))
    );
}

#[test]
fn compaction_summary_stays_before_volatile_working_set() {
    let tmp = tempdir().expect("tempdir");
    fs::create_dir_all(tmp.path().join("src")).expect("mkdir");
    fs::write(tmp.path().join("src/main.rs"), "fn main() {}").expect("write");

    let config = EngineConfig {
        workspace: tmp.path().to_path_buf(),
        ..Default::default()
    };
    let (mut engine, _handle) = Engine::new(config, &Config::default());
    engine
        .session
        .working_set
        .observe_user_message("continue in src/main.rs", tmp.path());
    engine.refresh_system_prompt(AppMode::Agent);
    engine.merge_compaction_summary(Some(SystemPrompt::Blocks(vec![SystemBlock {
        block_type: "text".to_string(),
        text: format!("{COMPACTION_SUMMARY_MARKER}\nsummary"),
        cache_control: None,
    }])));

    let Some(SystemPrompt::Blocks(blocks)) = &engine.session.system_prompt else {
        panic!("expected structured prompt blocks");
    };
    let summary_index = blocks
        .iter()
        .position(|block| block.text.contains(COMPACTION_SUMMARY_MARKER))
        .expect("summary block");
    let working_set_index = blocks
        .iter()
        .position(|block| block.text.contains(WORKING_SET_SUMMARY_MARKER))
        .expect("working-set block");

    assert!(summary_index < working_set_index);
    assert_eq!(working_set_index, blocks.len() - 1);
}

#[tokio::test]
async fn pre_request_refresh_skips_compaction_below_normal_threshold() {
    let capacity = CapacityControllerConfig {
        enabled: true,
        low_risk_max: 0.0,
        medium_risk_max: 1.0,
        min_turns_before_guardrail: 0,
        ..Default::default()
    };

    let mut engine = build_engine_with_capacity(capacity.clone());
    engine.config.capacity = capacity.clone();
    engine.capacity_controller = CapacityController::new(capacity);
    engine.turn_counter = 5;
    engine
        .capacity_controller
        .mark_turn_start(engine.turn_counter);
    engine.session.model = "deepseek-v4-pro".to_string();
    engine.config.model = "deepseek-v4-pro".to_string();

    for i in 0..20 {
        engine.session.messages.push(Message {
            role: "user".to_string(),
            content: vec![ContentBlock::Text {
                text: format!("small message {i}"),
                cache_control: None,
            }],
        });
    }

    let before = engine.estimated_input_tokens();
    let before_len = engine.session.messages.len();
    let turn = TurnContext::new(10);
    let applied = engine
        .run_capacity_pre_request_checkpoint(&turn, None, AppMode::Agent)
        .await;
    let after = engine.estimated_input_tokens();

    assert!(!applied);
    assert_eq!(after, before);
    assert_eq!(engine.session.messages.len(), before_len);
}

#[tokio::test]
async fn pre_request_refresh_invoked_when_medium_risk() {
    let capacity = CapacityControllerConfig {
        enabled: true,
        low_risk_max: 0.0,
        medium_risk_max: 1.0,
        min_turns_before_guardrail: 0,
        ..Default::default()
    };

    let mut engine = build_engine_with_capacity(capacity.clone());
    engine.config.capacity = capacity.clone();
    engine.capacity_controller = CapacityController::new(capacity);
    engine.turn_counter = 5;
    engine
        .capacity_controller
        .mark_turn_start(engine.turn_counter);

    // Pin the model to an explicit 128k-context variant so the pressure ratio stays
    // stable regardless of changes to the workspace-wide default model.
    engine.session.model = "deepseek-v3.2-128k".to_string();
    engine.config.model = "deepseek-v3.2-128k".to_string();

    let long = "x".repeat(5_000);
    for _ in 0..200 {
        engine.session.messages.push(Message {
            role: "user".to_string(),
            content: vec![ContentBlock::Text {
                text: long.clone(),
                cache_control: None,
            }],
        });
    }

    let before = engine.estimated_input_tokens();
    let turn = TurnContext::new(10);
    let applied = engine
        .run_capacity_pre_request_checkpoint(&turn, None, AppMode::Agent)
        .await;
    let after = engine.estimated_input_tokens();

    assert!(applied);
    assert!(after < before);
}

#[tokio::test]
async fn post_tool_replay_invoked_when_high_non_severe_risk() {
    let tmp = tempdir().expect("tempdir");
    fs::write(tmp.path().join("sample.txt"), "hello replay").expect("write");

    let capacity = CapacityControllerConfig {
        enabled: true,
        low_risk_max: 0.0,
        medium_risk_max: 0.0,
        severe_min_slack: -10.0,
        severe_violation_ratio: 2.0,
        min_turns_before_guardrail: 0,
        ..Default::default()
    };

    let mut engine = build_engine_with_capacity(capacity.clone());
    engine.session.workspace = tmp.path().to_path_buf();
    engine.config.workspace = tmp.path().to_path_buf();
    engine.config.capacity = capacity.clone();
    engine.capacity_controller = CapacityController::new(capacity);
    engine.turn_counter = 4;
    engine
        .capacity_controller
        .mark_turn_start(engine.turn_counter);

    let mut turn = TurnContext::new(10);
    let mut tool_call = TurnToolCall::new(
        "tool_read_1".to_string(),
        "read_file".to_string(),
        json!({ "path": "sample.txt" }),
    );
    tool_call.set_result(
        "hello replay".to_string(),
        std::time::Duration::from_millis(1),
    );
    turn.record_tool_call(tool_call);

    let registry = ToolRegistryBuilder::new()
        .with_read_only_file_tools()
        .build(engine.build_tool_context(AppMode::Agent, false));

    let restarted = engine
        .run_capacity_post_tool_checkpoint(
            &turn,
            AppMode::Agent,
            Some(&registry),
            Arc::new(RwLock::new(())),
            None,
            0,
            0,
        )
        .await;

    assert!(!restarted);
    let has_verification_note = engine.session.messages.iter().any(|msg| {
        msg.content.iter().any(|block| match block {
            ContentBlock::ToolResult { content, .. } => content.contains("[verification replay]"),
            _ => false,
        })
    });
    assert!(has_verification_note);
}

#[tokio::test]
async fn error_escalation_triggers_replan_when_severe_or_repeated_failures() {
    let tmp = tempdir().expect("tempdir");
    // Safety: scoped to test process; reset at end.
    unsafe {
        std::env::set_var(
            "DEEPSEEK_CAPACITY_MEMORY_DIR",
            tmp.path().to_string_lossy().to_string(),
        );
    }

    let capacity = CapacityControllerConfig {
        enabled: true,
        low_risk_max: 0.0,
        medium_risk_max: 0.0,
        min_turns_before_guardrail: 0,
        ..Default::default()
    };

    let mut engine = build_engine_with_capacity(capacity.clone());
    engine.config.capacity = capacity.clone();
    engine.capacity_controller = CapacityController::new(capacity);
    engine.turn_counter = 6;
    engine
        .capacity_controller
        .mark_turn_start(engine.turn_counter);

    for i in 0..10 {
        engine.session.messages.push(Message {
            role: if i % 2 == 0 { "user" } else { "assistant" }.to_string(),
            content: vec![ContentBlock::Text {
                text: format!("noise message {i}"),
                cache_control: None,
            }],
        });
    }
    engine.session.messages.push(Message {
        role: "user".to_string(),
        content: vec![ContentBlock::Text {
            text: "Please finish task".to_string(),
            cache_control: None,
        }],
    });

    let before_len = engine.session.messages.len();
    let turn = TurnContext::new(10);
    let restarted = engine
        .run_capacity_error_escalation_checkpoint(&turn, AppMode::Agent, 2, 2, &[])
        .await;

    assert!(restarted);
    assert!(engine.session.messages.len() < before_len);
    assert!(engine.session.messages.len() <= 2);

    let records = load_last_k_capacity_records(&engine.session.id, 1).expect("load memory");
    assert!(!records.is_empty());
    assert!(!records[0].canonical_state.goal.is_empty());
    unsafe {
        std::env::remove_var("DEEPSEEK_CAPACITY_MEMORY_DIR");
    }
}

#[tokio::test]
async fn controller_disabled_keeps_behavior_unchanged() {
    let capacity = CapacityControllerConfig {
        enabled: false,
        ..Default::default()
    };

    let mut engine = build_engine_with_capacity(capacity.clone());
    engine.config.capacity = capacity.clone();
    engine.capacity_controller = CapacityController::new(capacity);
    engine.turn_counter = 3;
    engine
        .capacity_controller
        .mark_turn_start(engine.turn_counter);

    let long = "y".repeat(5_000);
    for _ in 0..120 {
        engine.session.messages.push(Message {
            role: "user".to_string(),
            content: vec![ContentBlock::Text {
                text: long.clone(),
                cache_control: None,
            }],
        });
    }

    let before = engine.estimated_input_tokens();
    let before_len = engine.session.messages.len();
    let turn = TurnContext::new(10);
    let applied = engine
        .run_capacity_pre_request_checkpoint(&turn, None, AppMode::Agent)
        .await;
    let after = engine.estimated_input_tokens();
    let after_len = engine.session.messages.len();

    assert!(!applied);
    assert_eq!(before, after);
    assert_eq!(before_len, after_len);
}

#[test]
fn caller_policy_defaults_to_direct() {
    let tool = Tool {
        tool_type: None,
        name: "read_file".to_string(),
        description: "Read".to_string(),
        input_schema: json!({"type":"object"}),
        allowed_callers: Some(vec!["direct".to_string()]),
        defer_loading: Some(false),
        input_examples: None,
        strict: None,
        cache_control: None,
    };
    let direct = ToolCaller {
        caller_type: "direct".to_string(),
        tool_id: None,
    };
    let code = ToolCaller {
        caller_type: "code_execution_20250825".to_string(),
        tool_id: Some("srvtoolu_1".to_string()),
    };
    assert!(caller_allowed_for_tool(Some(&direct), Some(&tool)));
    assert!(!caller_allowed_for_tool(Some(&code), Some(&tool)));
    assert!(caller_allowed_for_tool(None, Some(&tool)));
}

#[test]
fn tool_search_activates_discovered_deferred_tools() {
    let mut catalog = vec![
        Tool {
            tool_type: None,
            name: "read_file".to_string(),
            description: "Read files".to_string(),
            input_schema: json!({"type":"object","properties":{"path":{"type":"string"}}}),
            allowed_callers: Some(vec!["direct".to_string()]),
            defer_loading: Some(true),
            input_examples: None,
            strict: None,
            cache_control: None,
        },
        Tool {
            tool_type: None,
            name: "grep_files".to_string(),
            description: "Search files".to_string(),
            input_schema: json!({"type":"object","properties":{"pattern":{"type":"string"}}}),
            allowed_callers: Some(vec!["direct".to_string()]),
            defer_loading: Some(true),
            input_examples: None,
            strict: None,
            cache_control: None,
        },
    ];
    ensure_advanced_tooling(&mut catalog);
    let mut active = initial_active_tools(&catalog);
    let result = execute_tool_search(
        TOOL_SEARCH_BM25_NAME,
        &json!({"query":"read file"}),
        &catalog,
        &mut active,
    )
    .expect("search succeeds");
    assert!(result.success);
    assert!(active.contains("read_file"));
}

#[tokio::test]
async fn code_execution_runs_python_and_returns_result_payload() {
    let tmp = tempdir().expect("tempdir");
    let result =
        execute_code_execution_tool(&json!({"code":"print('hello from code exec')"}), tmp.path())
            .await
            .expect("code execution should run");
    assert!(result.content.contains("hello from code exec"));
    assert!(result.content.contains("return_code"));
}

#[test]
fn deferred_tool_requests_are_auto_activated() {
    use std::collections::HashSet;

    let catalog = vec![Tool {
        tool_type: None,
        name: "exec_shell".to_string(),
        description: "Run shell commands".to_string(),
        input_schema: json!({"type":"object","properties":{"cmd":{"type":"string"}}}),
        allowed_callers: Some(vec!["direct".to_string()]),
        defer_loading: Some(true),
        input_examples: None,
        strict: None,
        cache_control: None,
    }];

    let mut active = HashSet::new();
    assert!(!active.contains("exec_shell"));
    assert!(maybe_activate_requested_deferred_tool(
        "exec_shell",
        &catalog,
        &mut active
    ));
    assert!(active.contains("exec_shell"));
}

#[test]
fn missing_tool_error_message_offers_suggestions() {
    let catalog = vec![
        Tool {
            tool_type: None,
            name: "read_file".to_string(),
            description: "Read file contents".to_string(),
            input_schema: json!({"type":"object","properties":{"path":{"type":"string"}}}),
            allowed_callers: Some(vec!["direct".to_string()]),
            defer_loading: Some(false),
            input_examples: None,
            strict: None,
            cache_control: None,
        },
        Tool {
            tool_type: None,
            name: "grep_files".to_string(),
            description: "Search file contents".to_string(),
            input_schema: json!({"type":"object","properties":{"pattern":{"type":"string"}}}),
            allowed_callers: Some(vec!["direct".to_string()]),
            defer_loading: Some(false),
            input_examples: None,
            strict: None,
            cache_control: None,
        },
    ];

    let message = missing_tool_error_message("reed_file", &catalog);
    assert!(message.contains("Did you mean:"));
    assert!(message.contains("read_file"));
    assert!(message.contains(TOOL_SEARCH_BM25_NAME));
}

#[test]
fn missing_tool_error_message_includes_discovery_guidance_when_no_match() {
    let catalog = vec![Tool {
        tool_type: None,
        name: "read_file".to_string(),
        description: "Read file contents".to_string(),
        input_schema: json!({"type":"object","properties":{"path":{"type":"string"}}}),
        allowed_callers: Some(vec!["direct".to_string()]),
        defer_loading: Some(false),
        input_examples: None,
        strict: None,
        cache_control: None,
    }];

    let message = missing_tool_error_message("totally_unknown_tool", &catalog);
    assert!(message.contains("not available in the current tool catalog"));
    assert!(message.contains(TOOL_SEARCH_BM25_NAME));
}

#[test]
fn filter_tool_call_delta_strips_bracket_marker() {
    let mut in_block = false;
    let visible = filter_tool_call_delta(
        "intro [TOOL_CALL]\n{\"tool\":\"x\"}\n[/TOOL_CALL] outro",
        &mut in_block,
    );
    assert!(!in_block);
    assert!(!visible.contains("[TOOL_CALL]"));
    assert!(!visible.contains("[/TOOL_CALL]"));
    assert!(!visible.contains("\"tool\":\"x\""));
    assert!(visible.contains("intro"));
    assert!(visible.contains("outro"));
}

#[test]
fn filter_tool_call_delta_strips_deepseek_xml_marker() {
    let mut in_block = false;
    let visible = filter_tool_call_delta(
        "before <deepseek:tool_call name=\"x\">payload</deepseek:tool_call> after",
        &mut in_block,
    );
    assert!(!in_block);
    for marker in TOOL_CALL_START_MARKERS {
        assert!(
            !visible.contains(marker),
            "visible text leaked start marker `{marker}`: {visible:?}"
        );
    }
    assert!(visible.contains("before"));
    assert!(visible.contains("after"));
}

#[test]
fn filter_tool_call_delta_strips_generic_tool_call_marker() {
    let mut in_block = false;
    let visible = filter_tool_call_delta(
        "lead <tool_call>\n{\"name\":\"do\"}\n</tool_call> tail",
        &mut in_block,
    );
    assert!(!in_block);
    assert!(!visible.contains("<tool_call"));
    assert!(!visible.contains("</tool_call>"));
    assert!(visible.contains("lead"));
    assert!(visible.contains("tail"));
}

#[test]
fn filter_tool_call_delta_strips_invoke_marker() {
    let mut in_block = false;
    let visible = filter_tool_call_delta(
        "alpha <invoke name=\"x\"><parameter name=\"k\">v</parameter></invoke> beta",
        &mut in_block,
    );
    assert!(!in_block);
    assert!(!visible.contains("<invoke "));
    assert!(!visible.contains("</invoke>"));
    assert!(visible.contains("alpha"));
    assert!(visible.contains("beta"));
}

#[test]
fn filter_tool_call_delta_strips_function_calls_marker() {
    let mut in_block = false;
    let visible = filter_tool_call_delta(
        "head <function_calls>\n{\"name\":\"x\"}\n</function_calls> tail",
        &mut in_block,
    );
    assert!(!in_block);
    assert!(!visible.contains("<function_calls>"));
    assert!(!visible.contains("</function_calls>"));
    assert!(visible.contains("head"));
    assert!(visible.contains("tail"));
}

#[test]
fn filter_tool_call_delta_handles_chunk_split_marker() {
    let mut in_block = false;
    // First chunk opens the wrapper but does not close it.
    let visible_a = filter_tool_call_delta("hello <tool_call>partial", &mut in_block);
    assert!(in_block, "filter must remember it is mid-wrapper");
    assert_eq!(visible_a, "hello ");

    // Second chunk continues inside the wrapper, then closes it and adds tail.
    let visible_b = filter_tool_call_delta("payload</tool_call> tail", &mut in_block);
    assert!(!in_block);
    assert_eq!(visible_b, " tail");
}

#[test]
fn filter_tool_call_delta_unmatched_open_suppresses_remainder() {
    let mut in_block = false;
    let visible = filter_tool_call_delta("ok [TOOL_CALL]rest of stream", &mut in_block);
    assert_eq!(visible, "ok ");
    assert!(
        in_block,
        "unmatched open must leave filter in tool-call mode"
    );
}

#[test]
fn filter_tool_call_delta_passes_through_clean_text() {
    let mut in_block = false;
    let input = "no markers here, just prose with code `<not a tag>`.";
    let visible = filter_tool_call_delta(input, &mut in_block);
    assert!(!in_block);
    assert_eq!(visible, input);
}

#[test]
fn contains_fake_tool_wrapper_detects_each_marker() {
    for marker in TOOL_CALL_START_MARKERS {
        let needle = format!("noise {marker} more noise");
        assert!(
            contains_fake_tool_wrapper(&needle),
            "marker `{marker}` should be detected"
        );
    }
}

#[test]
fn contains_fake_tool_wrapper_returns_false_on_clean_text() {
    assert!(!contains_fake_tool_wrapper(
        "plain assistant text without wrappers"
    ));
    assert!(!contains_fake_tool_wrapper(
        "`<tool` lookalike but not a real start marker"
    ));
}

#[test]
fn fake_wrapper_notice_is_compact_and_actionable() {
    // Keep this short so it fits cleanly in a single status line.
    assert!(FAKE_WRAPPER_NOTICE.len() < 120);
    assert!(FAKE_WRAPPER_NOTICE.contains("API tool channel"));
}

// ---- final_tool_input: bug-class regression for "<command>" placeholder ----
//
// Background: a streamed tool block carries its `input` in two pieces — an
// initial value at `ContentBlockStart` (often `{}`), then `InputJsonDelta`
// chunks that build up `input_buffer`. The TUI used to fire `ToolCallStarted`
// from `ContentBlockStart` with the empty initial input and never re-emit
// once args were known, so cells rendered the literal text `<command>` /
// `<file>` placeholders. The fix relocates the emission to `ContentBlockStop`
// and routes the input through `final_tool_input`, which prefers the parsed
// buffer over a stale empty placeholder.
fn tool_state(initial: serde_json::Value, buffer: &str) -> ToolUseState {
    ToolUseState {
        id: "t1".into(),
        name: "exec_shell".into(),
        input: initial,
        caller: None,
        input_buffer: buffer.into(),
    }
}

#[test]
fn final_tool_input_prefers_parsed_buffer_over_empty_initial() {
    // The exact regression: ContentBlockStart delivered `{}`, then args
    // streamed in via InputJsonDelta. The emitted ToolCallStarted must
    // carry the parsed buffer, not the placeholder.
    let state = tool_state(json!({}), r#"{"command": "ls -la"}"#);
    assert_eq!(final_tool_input(&state), json!({"command": "ls -la"}));
}

#[test]
fn final_tool_input_falls_back_to_initial_when_buffer_empty() {
    // Models occasionally embed args directly in the start frame and never
    // send any InputJsonDelta. We must still report those args.
    let state = tool_state(json!({"command": "echo hi"}), "");
    assert_eq!(final_tool_input(&state), json!({"command": "echo hi"}));
}

#[test]
fn final_tool_input_falls_back_to_initial_when_buffer_unparseable() {
    // If the model ships partial JSON we never managed to parse, we keep
    // whatever the per-delta parser last accepted (mirrored into `input`).
    let state = tool_state(json!({"command": "echo hi"}), "{not json");
    assert_eq!(final_tool_input(&state), json!({"command": "echo hi"}));
}