toolpath-opencode 0.4.0

//! [`OpencodeProjector`] — maps a [`ConversationView`] back to an
//! opencode [`Session`] (with messages and parts populated).

use std::collections::HashMap;
use std::path::PathBuf;

use serde_json::{Map, Value};
use toolpath_convo::{
    ConversationProjector, ConversationView, ConvoError, Result, Role, ToolInvocation, Turn,
};

use crate::types::{
    AssistantMessage, Message, MessageData, MessagePath, MessageTime, ModelRef, Part, PartData,
    ReasoningPart, Session, StepFinishPart, StepStartPart, TextPart, TimeRange, Tokens, ToolPart,
    ToolRunTime, ToolState, ToolStateCompleted, ToolStateError, UserMessage,
};

const DEFAULT_AGENT: &str = "build";
const DEFAULT_MODEL_PROVIDER: &str = "anthropic";
const DEFAULT_MODEL_ID: &str = "unknown";
const DEFAULT_VERSION: &str = "0.0.0-projected";

#[derive(Debug, Clone, Default)]
pub struct OpencodeProjector {
    pub project_id: Option<String>,
    pub directory: Option<PathBuf>,
    pub workspace_id: Option<String>,
    pub agent: Option<String>,
    pub default_model_provider: Option<String>,
    pub default_model_id: Option<String>,
    pub version: Option<String>,
    pub slug: Option<String>,
    pub title: Option<String>,
}

impl OpencodeProjector {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn with_project_id(mut self, id: impl Into<String>) -> Self {
        self.project_id = Some(id.into());
        self
    }

    pub fn with_directory(mut self, dir: impl Into<PathBuf>) -> Self {
        self.directory = Some(dir.into());
        self
    }

    pub fn with_workspace_id(mut self, id: impl Into<String>) -> Self {
        self.workspace_id = Some(id.into());
        self
    }

    pub fn with_agent(mut self, agent: impl Into<String>) -> Self {
        self.agent = Some(agent.into());
        self
    }

    pub fn with_version(mut self, v: impl Into<String>) -> Self {
        self.version = Some(v.into());
        self
    }

    pub fn with_title(mut self, title: impl Into<String>) -> Self {
        self.title = Some(title.into());
        self
    }
}

impl ConversationProjector for OpencodeProjector {
    type Output = Session;

    fn project(&self, view: &ConversationView) -> Result<Session> {
        project_view(self, view).map_err(ConvoError::Provider)
    }
}

fn project_view(
    cfg: &OpencodeProjector,
    view: &ConversationView,
) -> std::result::Result<Session, String> {
    let directory = cfg
        .directory
        .clone()
        .or_else(|| {
            view.turns
                .iter()
                .find_map(|t| t.environment.as_ref()?.working_dir.clone())
                .map(PathBuf::from)
        })
        .unwrap_or_else(|| PathBuf::from("/"));

    let project_id = cfg
        .project_id
        .clone()
        .unwrap_or_else(|| derive_project_id(&directory));

    let agent = cfg
        .agent
        .clone()
        .unwrap_or_else(|| DEFAULT_AGENT.to_string());
    let version = cfg
        .version
        .clone()
        .unwrap_or_else(|| DEFAULT_VERSION.to_string());

    let session_id = if view.id.starts_with("ses_") {
        view.id.clone()
    } else {
        mint_session_id(&view.id)
    };

    let time_created = view
        .started_at
        .map(|t| t.timestamp_millis())
        .or_else(|| {
            view.turns
                .first()
                .and_then(|t| parse_timestamp_ms(&t.timestamp))
        })
        .unwrap_or(0);
    let time_updated = view
        .last_activity
        .map(|t| t.timestamp_millis())
        .or_else(|| {
            view.turns
                .last()
                .and_then(|t| parse_timestamp_ms(&t.timestamp))
        })
        .unwrap_or(time_created);

    let title = cfg
        .title
        .clone()
        .or_else(|| {
            view.turns
                .iter()
                .filter(|t| matches!(t.role, Role::User))
                .map(|t| t.text.as_str())
                .find(|t| !t.is_empty() && !is_system_envelope(t))
                .map(truncate_title)
        })
        .unwrap_or_else(|| "Projected session".to_string());

    let slug = cfg.slug.clone().unwrap_or_else(|| slugify(&title));

    let mut messages: Vec<Message> = Vec::new();
    let mut prev_msg_id: Option<String> = None;
    let mut counter: u32 = 0;

    let default_provider = cfg
        .default_model_provider
        .clone()
        .unwrap_or_else(|| DEFAULT_MODEL_PROVIDER.to_string());
    let default_model = cfg
        .default_model_id
        .clone()
        .unwrap_or_else(|| DEFAULT_MODEL_ID.to_string());

    for turn in &view.turns {
        match turn.role {
            Role::User => {
                let msg = build_user_message(
                    turn,
                    &session_id,
                    &mut counter,
                    &agent,
                    &default_provider,
                    &default_model,
                );
                prev_msg_id = Some(msg.id.clone());
                messages.push(msg);
            }
            Role::Assistant => {
                let parent = prev_msg_id
                    .clone()
                    .unwrap_or_else(|| mint_message_id(&session_id, counter));
                let msg = build_assistant_message(
                    turn,
                    &session_id,
                    &mut counter,
                    parent,
                    &directory,
                    &agent,
                    &default_provider,
                    &default_model,
                );
                prev_msg_id = Some(msg.id.clone());
                messages.push(msg);
            }
            Role::System | Role::Other(_) => {
                // opencode has no system-role message variant; fold the
                // text into the next user/assistant turn's context by
                // skipping. The system prompt itself rides on
                // UserMessage.system if needed.
            }
        }
    }

    Ok(Session {
        id: session_id,
        project_id,
        workspace_id: cfg.workspace_id.clone(),
        parent_id: None,
        slug,
        directory,
        title,
        version,
        share_url: None,
        summary_additions: None,
        summary_deletions: None,
        summary_files: None,
        time_created,
        time_updated,
        time_compacting: None,
        time_archived: None,
        messages,
    })
}

fn build_user_message(
    turn: &Turn,
    session_id: &str,
    counter: &mut u32,
    agent: &str,
    default_provider: &str,
    default_model: &str,
) -> Message {
    *counter += 1;
    let msg_id = mint_message_id(session_id, *counter);
    let time_created = parse_timestamp_ms(&turn.timestamp).unwrap_or(0);

    let opencode_extras = opencode_extras(turn);
    let model = opencode_extras
        .as_ref()
        .and_then(|m| m.get("model"))
        .and_then(|v| serde_json::from_value::<ModelRef>(v.clone()).ok())
        .unwrap_or_else(|| ModelRef {
            provider_id: default_provider.to_string(),
            model_id: default_model.to_string(),
            variant: None,
        });

    let user = UserMessage {
        time: MessageTime {
            created: time_created,
            completed: None,
        },
        agent: agent.to_string(),
        model,
        format: None,
        summary: Some(crate::types::UserSummary {
            title: None,
            body: None,
            diffs: vec![],
            extra: HashMap::new(),
        }),
        system: None,
        tools: None,
        extra: HashMap::new(),
    };

    let mut parts: Vec<Part> = Vec::new();
    if !turn.text.is_empty() {
        *counter += 1;
        parts.push(Part {
            id: mint_part_id(session_id, *counter),
            message_id: msg_id.clone(),
            session_id: session_id.to_string(),
            time_created,
            time_updated: time_created,
            data: PartData::Text(TextPart {
                text: turn.text.clone(),
                synthetic: None,
                ignored: None,
                time: None,
                metadata: None,
                extra: HashMap::new(),
            }),
        });
    }

    Message {
        id: msg_id,
        session_id: session_id.to_string(),
        time_created,
        time_updated: time_created,
        data: MessageData::User(user),
        parts,
    }
}

#[allow(clippy::too_many_arguments)]
fn build_assistant_message(
    turn: &Turn,
    session_id: &str,
    counter: &mut u32,
    parent_id: String,
    cwd: &std::path::Path,
    agent: &str,
    default_provider: &str,
    default_model: &str,
) -> Message {
    *counter += 1;
    let msg_id = mint_message_id(session_id, *counter);
    let time_created = parse_timestamp_ms(&turn.timestamp).unwrap_or(0);

    let extras = opencode_extras(turn);
    let provider_id = extras
        .as_ref()
        .and_then(|m| m.get("providerID"))
        .and_then(Value::as_str)
        .map(str::to_string)
        .unwrap_or_else(|| default_provider.to_string());
    let model_id = turn
        .model
        .clone()
        .or_else(|| {
            extras
                .as_ref()
                .and_then(|m| m.get("modelID"))
                .and_then(Value::as_str)
                .map(str::to_string)
        })
        .unwrap_or_else(|| default_model.to_string());

    let tokens = turn
        .token_usage
        .as_ref()
        .map(|u| {
            let input = u.input_tokens.unwrap_or(0) as u64;
            let output = u.output_tokens.unwrap_or(0) as u64;
            let cache_read = u.cache_read_tokens.unwrap_or(0) as u64;
            let cache_write = u.cache_write_tokens.unwrap_or(0) as u64;
            Tokens {
                total: Some(input + output + cache_read + cache_write),
                input,
                output,
                reasoning: 0,
                cache: crate::types::TokenCache {
                    read: cache_read,
                    write: cache_write,
                },
            }
        })
        .unwrap_or_default();

    let assistant = AssistantMessage {
        parent_id,
        time: MessageTime {
            created: time_created,
            completed: Some(time_created),
        },
        error: None,
        agent: agent.to_string(),
        // Required by opencode's schema (deprecated but still validated).
        mode: Some(agent.to_string()),
        model_id: model_id.clone(),
        provider_id: provider_id.clone(),
        path: MessagePath {
            cwd: cwd.to_path_buf(),
            root: cwd.to_path_buf(),
        },
        summary: None,
        cost: 0.0,
        tokens: tokens.clone(),
        structured: None,
        variant: None,
        finish: turn.stop_reason.clone(),
        extra: HashMap::new(),
    };

    let mut parts: Vec<Part> = Vec::new();
    let snapshot = extras
        .as_ref()
        .and_then(|m| m.get("snapshots"))
        .and_then(Value::as_array)
        .and_then(|a| a.first())
        .and_then(Value::as_str)
        .map(str::to_string);

    *counter += 1;
    parts.push(Part {
        id: mint_part_id(session_id, *counter),
        message_id: msg_id.clone(),
        session_id: session_id.to_string(),
        time_created,
        time_updated: time_created,
        data: PartData::StepStart(StepStartPart {
            snapshot: snapshot.clone(),
            extra: HashMap::new(),
        }),
    });

    if let Some(thinking) = &turn.thinking
        && !thinking.is_empty()
    {
        *counter += 1;
        parts.push(Part {
            id: mint_part_id(session_id, *counter),
            message_id: msg_id.clone(),
            session_id: session_id.to_string(),
            time_created,
            time_updated: time_created,
            data: PartData::Reasoning(ReasoningPart {
                text: thinking.clone(),
                time: Some(TimeRange {
                    start: time_created,
                    end: Some(time_created),
                }),
                metadata: None,
                extra: HashMap::new(),
            }),
        });
    }

    if !turn.text.is_empty() {
        *counter += 1;
        parts.push(Part {
            id: mint_part_id(session_id, *counter),
            message_id: msg_id.clone(),
            session_id: session_id.to_string(),
            time_created,
            time_updated: time_created,
            data: PartData::Text(TextPart {
                text: turn.text.clone(),
                synthetic: None,
                ignored: None,
                time: Some(TimeRange {
                    start: time_created,
                    end: Some(time_created),
                }),
                metadata: None,
                extra: HashMap::new(),
            }),
        });
    }

    for tu in &turn.tool_uses {
        *counter += 1;
        let part_id = mint_part_id(session_id, *counter);
        parts.push(Part {
            id: part_id,
            message_id: msg_id.clone(),
            session_id: session_id.to_string(),
            time_created,
            time_updated: time_created,
            data: PartData::Tool(build_tool_part(tu, time_created)),
        });
    }

    *counter += 1;
    parts.push(Part {
        id: mint_part_id(session_id, *counter),
        message_id: msg_id.clone(),
        session_id: session_id.to_string(),
        time_created,
        time_updated: time_created,
        data: PartData::StepFinish(StepFinishPart {
            reason: turn
                .stop_reason
                .clone()
                .unwrap_or_else(|| "stop".to_string()),
            snapshot,
            cost: 0.0,
            tokens,
            extra: HashMap::new(),
        }),
    });

    Message {
        id: msg_id,
        session_id: session_id.to_string(),
        time_created,
        time_updated: time_created,
        data: MessageData::Assistant(assistant),
        parts,
    }
}

fn build_tool_part(tu: &ToolInvocation, time_created: i64) -> ToolPart {
    let tool_name = native_tool_name(tu);
    let input = normalize_tool_input(&tool_name, &tu.input);
    let title = synthesize_title(&tool_name, &input);

    let state = match &tu.result {
        Some(r) if r.is_error => ToolState::Error(ToolStateError {
            input,
            error: r.content.clone(),
            metadata: None,
            time: ToolRunTime {
                start: time_created,
                end: time_created,
                compacted: None,
            },
        }),
        Some(r) => {
            let metadata = synthesize_metadata(&tool_name, &r.content, &input);
            ToolState::Completed(ToolStateCompleted {
                input,
                output: r.content.clone(),
                title: title.clone(),
                metadata,
                time: ToolRunTime {
                    start: time_created,
                    end: time_created,
                    compacted: None,
                },
                attachments: None,
            })
        }
        None => ToolState::Completed(ToolStateCompleted {
            input,
            output: String::new(),
            title: title.clone(),
            metadata: Value::Object(Map::new()),
            time: ToolRunTime {
                start: time_created,
                end: time_created,
                compacted: None,
            },
            attachments: None,
        }),
    };

    ToolPart {
        tool: tool_name,
        call_id: tu.id.clone(),
        state,
        metadata: None,
        extra: HashMap::new(),
    }
}

fn native_tool_name(tu: &ToolInvocation) -> String {
    if crate::provider::tool_category(&tu.name).is_some() {
        return tu.name.clone();
    }
    if let Some(cat) = tu.category
        && let Some(remap) = crate::provider::native_name(cat, &tu.input)
    {
        return remap.to_string();
    }
    tu.name.clone()
}

fn synthesize_title(tool: &str, input: &Value) -> String {
    match tool {
        "bash" => input
            .get("description")
            .and_then(Value::as_str)
            .or_else(|| input.get("command").and_then(Value::as_str))
            .unwrap_or("")
            .to_string(),
        "read" | "edit" | "write" => input
            .get("filePath")
            .and_then(Value::as_str)
            .unwrap_or("")
            .to_string(),
        "grep" => input
            .get("pattern")
            .and_then(Value::as_str)
            .unwrap_or("")
            .to_string(),
        "glob" => input
            .get("pattern")
            .or_else(|| input.get("path"))
            .and_then(Value::as_str)
            .unwrap_or("")
            .to_string(),
        _ => String::new(),
    }
}

/// Map Claude/Codex-shape arg keys onto opencode's camelCase vocabulary
/// — opencode's TUI reads `filePath`, `oldString`, `newString` and shows
/// "preparing edit..." when those are missing.
fn normalize_tool_input(tool: &str, input: &Value) -> Value {
    let Some(obj) = input.as_object() else {
        return input.clone();
    };
    let rename = |obj: &mut Map<String, Value>, from: &str, to: &str| {
        if obj.contains_key(to) {
            return;
        }
        if let Some(v) = obj.remove(from) {
            obj.insert(to.to_string(), v);
        }
    };
    let mut out = obj.clone();
    match tool {
        "read" => {
            rename(&mut out, "file_path", "filePath");
        }
        "write" => {
            rename(&mut out, "file_path", "filePath");
        }
        "edit" => {
            rename(&mut out, "file_path", "filePath");
            rename(&mut out, "old_string", "oldString");
            rename(&mut out, "new_string", "newString");
        }
        _ => {}
    }
    Value::Object(out)
}

fn synthesize_metadata(tool: &str, output: &str, input: &Value) -> Value {
    let mut m = Map::new();
    match tool {
        "bash" => {
            m.insert("output".to_string(), Value::String(output.to_string()));
            m.insert("exit".to_string(), Value::Number(0.into()));
            m.insert("truncated".to_string(), Value::Bool(false));
        }
        "edit" => {
            m.insert("diagnostics".to_string(), Value::Object(Map::new()));
            if let Some(diff) = synthesize_edit_diff(input) {
                m.insert("diff".to_string(), Value::String(diff));
            }
        }
        "write" => {
            m.insert("diagnostics".to_string(), Value::Object(Map::new()));
        }
        "read" => {
            m.insert("diagnostics".to_string(), Value::Object(Map::new()));
        }
        _ => {}
    }
    Value::Object(m)
}

fn synthesize_edit_diff(input: &Value) -> Option<String> {
    let path = input.get("filePath").and_then(Value::as_str)?;
    let old = input.get("oldString").and_then(Value::as_str)?;
    let new_s = input.get("newString").and_then(Value::as_str)?;
    let old_lines: Vec<&str> = if old.is_empty() {
        vec![]
    } else {
        old.split('\n').collect()
    };
    let new_lines: Vec<&str> = if new_s.is_empty() {
        vec![]
    } else {
        new_s.split('\n').collect()
    };
    let old_count = old_lines.len();
    let new_count = new_lines.len();
    let old_start = if old_count == 0 { 0 } else { 1 };
    let new_start = if new_count == 0 { 0 } else { 1 };
    let mut out = String::new();
    out.push_str(&format!("Index: {}\n", path));
    out.push_str("===================================================================\n");
    out.push_str(&format!("--- {}\n", path));
    out.push_str(&format!("+++ {}\n", path));
    out.push_str(&format!(
        "@@ -{},{} +{},{} @@\n",
        old_start, old_count, new_start, new_count
    ));
    for line in &old_lines {
        out.push_str(&format!("-{}\n", line));
    }
    for line in &new_lines {
        out.push_str(&format!("+{}\n", line));
    }
    Some(out)
}

fn opencode_extras(_turn: &Turn) -> Option<&'static Map<String, Value>> {
    None
}

fn mint_session_id(seed: &str) -> String {
    format!("ses_{}", stable_hex24(seed))
}

fn mint_message_id(session_id: &str, n: u32) -> String {
    format!("msg_{}", stable_hex24(&format!("{}-msg-{}", session_id, n)))
}

fn mint_part_id(session_id: &str, n: u32) -> String {
    format!("prt_{}", stable_hex24(&format!("{}-prt-{}", session_id, n)))
}

fn stable_hex24(seed: &str) -> String {
    use sha1::{Digest, Sha1};
    let mut h = Sha1::new();
    h.update(seed.as_bytes());
    let bytes = h.finalize();
    hex::encode(&bytes[..12])
}

fn parse_timestamp_ms(ts: &str) -> Option<i64> {
    chrono::DateTime::parse_from_rfc3339(ts)
        .ok()
        .map(|dt| dt.timestamp_millis())
}

fn truncate_title(text: &str) -> String {
    let trimmed = text.trim();
    let first_line = trimmed.lines().next().unwrap_or("").trim();
    first_line.chars().take(120).collect()
}

fn is_system_envelope(text: &str) -> bool {
    let trimmed = text.trim_start();
    trimmed.starts_with('<') && trimmed.contains('>')
}

fn slugify(title: &str) -> String {
    let mut out = String::new();
    let mut last_dash = true;
    for c in title.chars().take(60) {
        if c.is_ascii_alphanumeric() {
            out.push(c.to_ascii_lowercase());
            last_dash = false;
        } else if !last_dash {
            out.push('-');
            last_dash = true;
        }
    }
    let trimmed = out.trim_matches('-').to_string();
    if trimmed.is_empty() {
        "session".to_string()
    } else {
        trimmed
    }
}

/// Best-effort fallback when the caller hasn't supplied a project_id.
/// Real opencode keys this off the first-root-commit SHA; for projected
/// sessions we use the SHA-1 of the worktree path as a stable
/// substitute.
fn derive_project_id(directory: &std::path::Path) -> String {
    stable_hex40(directory.to_string_lossy().as_bytes())
}

fn stable_hex40(seed: &[u8]) -> String {
    use sha1::{Digest, Sha1};
    let mut h = Sha1::new();
    h.update(seed);
    hex::encode(h.finalize())
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;
    use toolpath_convo::{ToolCategory, ToolInvocation, ToolResult};

    fn user_turn(text: &str) -> Turn {
        Turn {
            id: "u1".into(),
            parent_id: None,
            role: Role::User,
            timestamp: "2026-04-21T12:00:00.000Z".into(),
            text: text.into(),
            thinking: None,
            tool_uses: vec![],
            model: None,
            stop_reason: None,
            token_usage: None,
            environment: None,
            delegations: vec![],
            file_mutations: Vec::new(),
        }
    }

    fn assistant_turn(text: &str) -> Turn {
        Turn {
            id: "a1".into(),
            parent_id: None,
            role: Role::Assistant,
            timestamp: "2026-04-21T12:00:01.000Z".into(),
            text: text.into(),
            thinking: None,
            tool_uses: vec![],
            model: Some("claude-sonnet-4-6".into()),
            stop_reason: Some("stop".into()),
            token_usage: None,
            environment: None,
            delegations: vec![],
            file_mutations: Vec::new(),
        }
    }

    fn view_with(turns: Vec<Turn>) -> ConversationView {
        ConversationView {
            id: "session-uuid".into(),
            started_at: None,
            last_activity: None,
            turns,
            total_usage: None,
            provider_id: Some("opencode".into()),
            files_changed: vec![],
            session_ids: vec![],
            events: vec![],
            ..Default::default()
        }
    }

    #[test]
    fn empty_view_yields_session_with_no_messages() {
        let s = OpencodeProjector::default()
            .project(&view_with(vec![]))
            .unwrap();
        assert!(s.id.starts_with("ses_"));
        assert!(s.messages.is_empty());
    }

    #[test]
    fn user_turn_becomes_user_message_with_text_part() {
        let s = OpencodeProjector::default()
            .project(&view_with(vec![user_turn("hello")]))
            .unwrap();
        assert_eq!(s.messages.len(), 1);
        let m = &s.messages[0];
        assert!(m.id.starts_with("msg_"));
        assert!(matches!(m.data, MessageData::User(_)));
        assert_eq!(m.parts.len(), 1);
        match &m.parts[0].data {
            PartData::Text(t) => assert_eq!(t.text, "hello"),
            _ => panic!("expected Text"),
        }
    }

    #[test]
    fn assistant_turn_emits_step_start_text_step_finish() {
        let s = OpencodeProjector::default()
            .project(&view_with(vec![assistant_turn("done")]))
            .unwrap();
        assert_eq!(s.messages.len(), 1);
        let kinds: Vec<&str> = s.messages[0].parts.iter().map(|p| p.data.kind()).collect();
        assert_eq!(kinds, vec!["step-start", "text", "step-finish"]);
    }

    #[test]
    fn tool_call_lands_as_tool_part() {
        let mut t = assistant_turn("");
        t.tool_uses = vec![ToolInvocation {
            id: "call_x".into(),
            name: "Bash".into(),
            input: json!({"command": "ls"}),
            result: Some(ToolResult {
                content: "out\n".into(),
                is_error: false,
            }),
            category: Some(ToolCategory::Shell),
        }];
        let s = OpencodeProjector::default()
            .project(&view_with(vec![t]))
            .unwrap();
        let parts = &s.messages[0].parts;
        let tool_part = parts
            .iter()
            .find(|p| matches!(p.data, PartData::Tool(_)))
            .expect("tool part");
        match &tool_part.data {
            PartData::Tool(tp) => {
                assert_eq!(tp.tool, "bash");
                assert_eq!(tp.call_id, "call_x");
                match &tp.state {
                    ToolState::Completed(c) => {
                        assert_eq!(c.output, "out\n");
                        assert_eq!(c.input["command"], "ls");
                        assert_eq!(c.metadata["exit"], 0);
                    }
                    _ => panic!("expected completed state"),
                }
            }
            _ => panic!("expected tool part"),
        }
    }

    #[test]
    fn errored_tool_use_produces_error_state() {
        let mut t = assistant_turn("");
        t.tool_uses = vec![ToolInvocation {
            id: "c".into(),
            name: "bash".into(),
            input: json!({"command": "false"}),
            result: Some(ToolResult {
                content: "exit 1".into(),
                is_error: true,
            }),
            category: Some(ToolCategory::Shell),
        }];
        let s = OpencodeProjector::default()
            .project(&view_with(vec![t]))
            .unwrap();
        let tp = s.messages[0]
            .parts
            .iter()
            .find_map(|p| match &p.data {
                PartData::Tool(tp) => Some(tp),
                _ => None,
            })
            .unwrap();
        assert!(matches!(tp.state, ToolState::Error(_)));
    }

    #[test]
    fn foreign_tool_name_remaps_via_category() {
        let mut t = assistant_turn("");
        t.tool_uses = vec![ToolInvocation {
            id: "c".into(),
            name: "Edit".into(),
            input: json!({"file_path": "x.rs", "old_string": "a", "new_string": "b"}),
            result: None,
            category: Some(ToolCategory::FileWrite),
        }];
        let s = OpencodeProjector::default()
            .project(&view_with(vec![t]))
            .unwrap();
        let tp = s.messages[0]
            .parts
            .iter()
            .find_map(|p| match &p.data {
                PartData::Tool(tp) => Some(tp),
                _ => None,
            })
            .unwrap();
        assert_eq!(tp.tool, "edit");
    }

    #[test]
    fn assistant_thinking_emits_reasoning_part() {
        let mut t = assistant_turn("ok");
        t.thinking = Some("considering options".into());
        let s = OpencodeProjector::default()
            .project(&view_with(vec![t]))
            .unwrap();
        let kinds: Vec<&str> = s.messages[0].parts.iter().map(|p| p.data.kind()).collect();
        assert_eq!(
            kinds,
            vec!["step-start", "reasoning", "text", "step-finish"]
        );
    }

    #[test]
    fn assistant_parent_id_chains_to_prior_user_message() {
        let s = OpencodeProjector::default()
            .project(&view_with(vec![user_turn("hi"), assistant_turn("ok")]))
            .unwrap();
        let user_id = s.messages[0].id.clone();
        match &s.messages[1].data {
            MessageData::Assistant(a) => assert_eq!(a.parent_id, user_id),
            _ => panic!("expected assistant"),
        }
    }
}