deepseek-tui 0.8.4

#![allow(dead_code)]
//! System prompts for different modes.
//!
//! Prompts are assembled from composable layers loaded at compile time:
//!   base.md → personality overlay → mode delta → approval policy
//!
//! This keeps each concern in its own file and makes prompt tuning
//! a single-file operation.

use crate::models::SystemPrompt;
use crate::project_context::{ProjectContext, load_project_context_with_parents};
use crate::tui::app::AppMode;
use std::path::Path;

/// Conventional location for the structured session-handoff artifact (#32).
/// A previous session writes it on exit / `/compact`; the next session reads
/// it back on startup and prepends it to the system prompt so a fresh agent
/// doesn't have to re-discover open blockers from scratch.
pub const HANDOFF_RELATIVE_PATH: &str = ".deepseek/handoff.md";

/// Read the workspace-local handoff artifact, if present, and format it as a
/// system-prompt block. Returns `None` when the file is absent or empty so
/// callers can keep the default-uncluttered prompt for fresh workspaces.
fn load_handoff_block(workspace: &Path) -> Option<String> {
    let path = workspace.join(HANDOFF_RELATIVE_PATH);
    let raw = std::fs::read_to_string(&path).ok()?;
    let trimmed = raw.trim();
    if trimmed.is_empty() {
        return None;
    }
    Some(format!(
        "## Previous Session Handoff\n\nThe previous session in this workspace left a handoff at `{}`. Consider it the first artifact to read on this turn — open blockers, in-flight changes, and recent decisions live there. Update or rewrite it before exiting if state changes materially.\n\n{}",
        HANDOFF_RELATIVE_PATH, trimmed
    ))
}

// ── Prompt layers loaded at compile time ──────────────────────────────

/// Core: task execution, tool-use rules, output format, toolbox reference,
/// "When NOT to use" guidance, sub-agent sentinel protocol.
pub const BASE_PROMPT: &str = include_str!("prompts/base.md");

/// Personality overlays — voice and tone.
pub const CALM_PERSONALITY: &str = include_str!("prompts/personalities/calm.md");
pub const PLAYFUL_PERSONALITY: &str = include_str!("prompts/personalities/playful.md");

/// Mode deltas — permissions, workflow expectations, mode-specific rules.
pub const AGENT_MODE: &str = include_str!("prompts/modes/agent.md");
pub const PLAN_MODE: &str = include_str!("prompts/modes/plan.md");
pub const YOLO_MODE: &str = include_str!("prompts/modes/yolo.md");

/// Approval-policy overlays — whether tool calls are auto-approved,
/// require confirmation, or are blocked.
pub const AUTO_APPROVAL: &str = include_str!("prompts/approvals/auto.md");
pub const SUGGEST_APPROVAL: &str = include_str!("prompts/approvals/suggest.md");
pub const NEVER_APPROVAL: &str = include_str!("prompts/approvals/never.md");

/// Compaction handoff template — written into the system prompt so the
/// model knows the format to use when writing `.deepseek/handoff.md`.
pub const COMPACT_TEMPLATE: &str = include_str!("prompts/compact.md");

// ── Legacy prompt constants (kept for backwards compatibility) ────────

/// Legacy base prompt (agent.txt — now decomposed into base.md + overlays).
/// Still available for callers that haven't migrated to the layered API.
pub const AGENT_PROMPT: &str = include_str!("prompts/agent.txt");
pub const YOLO_PROMPT: &str = include_str!("prompts/yolo.txt");
pub const PLAN_PROMPT: &str = include_str!("prompts/plan.txt");

// ── Personality selection ─────────────────────────────────────────────

/// Which personality overlay to apply.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Personality {
    /// Cool, spatial, reserved — the default.
    Calm,
    /// Warm, energetic, playful — alternative for fun mode.
    Playful,
}

impl Personality {
    /// Resolve from the `calm_mode` settings flag.
    /// When `calm_mode` is true → Calm; when false → Playful (future).
    /// For now, always returns Calm — Playful is wired but opt-in.
    #[must_use]
    pub fn from_settings(calm_mode: bool) -> Self {
        if calm_mode {
            Self::Calm
        } else {
            // Future: when playful mode is exposed in settings, return Playful here.
            // For now, calm is the only default.
            Self::Calm
        }
    }

    fn prompt(self) -> &'static str {
        match self {
            Self::Calm => CALM_PERSONALITY,
            Self::Playful => PLAYFUL_PERSONALITY,
        }
    }
}

// ── Composition ───────────────────────────────────────────────────────

fn mode_prompt(mode: AppMode) -> &'static str {
    match mode {
        AppMode::Agent => AGENT_MODE,
        AppMode::Yolo => YOLO_MODE,
        AppMode::Plan => PLAN_MODE,
    }
}

fn approval_prompt(mode: AppMode) -> &'static str {
    match mode {
        AppMode::Agent => SUGGEST_APPROVAL,
        AppMode::Yolo => AUTO_APPROVAL,
        AppMode::Plan => NEVER_APPROVAL,
    }
}

/// Compose the full system prompt in deterministic order:
///   1. base.md        — core identity, toolbox, execution contract
///   2. personality    — voice and tone overlay
///   3. mode delta     — mode-specific permissions and workflow
///   4. approval policy — tool-approval behavior
///
/// Each layer is separated by a blank line for readability in the
/// rendered prompt (the model sees them as contiguous sections).
pub fn compose_prompt(mode: AppMode, personality: Personality) -> String {
    let parts: [&str; 4] = [
        BASE_PROMPT.trim(),
        personality.prompt().trim(),
        mode_prompt(mode).trim(),
        approval_prompt(mode).trim(),
    ];

    let mut out =
        String::with_capacity(parts.iter().map(|p| p.len()).sum::<usize>() + (parts.len() - 1) * 2);
    for (i, part) in parts.iter().enumerate() {
        if i > 0 {
            out.push('\n');
            out.push('\n');
        }
        out.push_str(part);
    }
    out
}

/// Compose for the default personality (Calm).
fn compose_mode_prompt(mode: AppMode) -> String {
    compose_prompt(mode, Personality::Calm)
}

// ── Public API ────────────────────────────────────────────────────────

/// Get the system prompt for a specific mode (default Calm personality).
pub fn system_prompt_for_mode(mode: AppMode) -> SystemPrompt {
    SystemPrompt::Text(compose_mode_prompt(mode))
}

/// Get the system prompt for a specific mode with explicit personality.
pub fn system_prompt_for_mode_with_personality(
    mode: AppMode,
    personality: Personality,
) -> SystemPrompt {
    SystemPrompt::Text(compose_prompt(mode, personality))
}

/// Get the system prompt for a specific mode with project context.
pub fn system_prompt_for_mode_with_context(
    mode: AppMode,
    workspace: &Path,
    working_set_summary: Option<&str>,
) -> SystemPrompt {
    system_prompt_for_mode_with_context_and_skills(mode, workspace, working_set_summary, None)
}

/// Get the system prompt for a specific mode with project and skills context.
///
/// **Volatile-content-last invariant.** Blocks are appended in order from
/// most-static to most-volatile so DeepSeek's KV prefix cache hits the
/// longest possible byte prefix turn-over-turn:
///
///   1. mode prompt (compile-time constant)
///   2. project context / fallback (workspace-static)
///   3. skills block (skills-dir-static)
///   4. `## Context Management` (compile-time constant, Agent/Yolo only)
///   5. compaction handoff template (compile-time constant)
///   6. handoff block — file-backed; rewritten by `/compact` and on exit
///   7. working-set summary — drifts when a new path is observed
///
/// Anything appended after a volatile block forfeits the cache for the rest
/// of the request. New blocks belong above the handoff/working-set boundary
/// unless they themselves are turn-volatile.
pub fn system_prompt_for_mode_with_context_and_skills(
    mode: AppMode,
    workspace: &Path,
    working_set_summary: Option<&str>,
    skills_dir: Option<&Path>,
) -> SystemPrompt {
    let mode_prompt = compose_mode_prompt(mode);

    // Load project context from workspace
    let project_context = load_project_context_with_parents(workspace);

    // 1–2. Mode prompt + project context (or fallback automap).
    let mut full_prompt = if let Some(project_block) = project_context.as_system_block() {
        format!("{}\n\n{}", mode_prompt, project_block)
    } else {
        // Fallback: Generate an automatic project map summary
        let summary = crate::utils::summarize_project(workspace);
        let tree = crate::utils::project_tree(workspace, 2); // Shallow tree for prompt
        format!(
            "{}\n\n### Project Structure (Automatic Map)\n**Summary:** {}\n\n**Tree:**\n```\n{}\n```",
            mode_prompt, summary, tree
        )
    };

    // 3. Skills block.
    if let Some(skills_block) = skills_dir.and_then(crate::skills::render_available_skills_context)
    {
        full_prompt = format!("{full_prompt}\n\n{skills_block}");
    }

    // 4. Context Management (Agent / Yolo only).
    if matches!(mode, AppMode::Agent | AppMode::Yolo) {
        full_prompt.push_str(
            "\n\n## Context Management\n\n\
             When the conversation gets long (you'll see a context usage indicator), you can:\n\
             1. Use `/compact` to summarize earlier context and free up space\n\
             2. The system will preserve important information (files you're working on, recent messages, tool results)\n\
             3. After compaction, you'll see a summary of what was discussed and can continue seamlessly\n\n\
             If you notice context is getting long (>80%), proactively suggest using `/compact` to the user."
        );
    }

    // 5. Compaction handoff template — so the model knows the format to use
    //    when writing `.deepseek/handoff.md` on exit / `/compact`.
    full_prompt.push_str("\n\n");
    full_prompt.push_str(COMPACT_TEMPLATE);

    // ── Volatile-content boundary ─────────────────────────────────────────
    // Everything below drifts mid-session and busts the prefix cache for
    // bytes that follow. Keep new static blocks above this comment.

    // 6. Previous-session handoff (file-backed, rewritten by `/compact`).
    if let Some(handoff_block) = load_handoff_block(workspace) {
        full_prompt = format!("{full_prompt}\n\n{handoff_block}");
    }

    // 7. Working-set summary (drifts when a new path is observed).
    if let Some(summary) = working_set_summary
        && !summary.trim().is_empty()
    {
        full_prompt = format!("{full_prompt}\n\n{summary}");
    }

    SystemPrompt::Text(full_prompt)
}

/// Build a system prompt with explicit project context
pub fn build_system_prompt(base: &str, project_context: Option<&ProjectContext>) -> SystemPrompt {
    let full_prompt =
        match project_context.and_then(super::project_context::ProjectContext::as_system_block) {
            Some(project_block) => format!("{}\n\n{}", base.trim(), project_block),
            None => base.trim().to_string(),
        };
    SystemPrompt::Text(full_prompt)
}

// ── Legacy functions for backwards compatibility ──────────────────────

pub fn base_system_prompt() -> SystemPrompt {
    SystemPrompt::Text(BASE_PROMPT.trim().to_string())
}

pub fn normal_system_prompt() -> SystemPrompt {
    system_prompt_for_mode(AppMode::Agent)
}

pub fn agent_system_prompt() -> SystemPrompt {
    system_prompt_for_mode(AppMode::Agent)
}

pub fn yolo_system_prompt() -> SystemPrompt {
    system_prompt_for_mode(AppMode::Yolo)
}

pub fn plan_system_prompt() -> SystemPrompt {
    system_prompt_for_mode(AppMode::Plan)
}

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

    /// Discriminator unique to the injected handoff block (not present in the
    /// agent prompt's own discussion of the convention).
    const HANDOFF_BLOCK_MARKER: &str = "left a handoff at `.deepseek/handoff.md`";

    #[test]
    fn handoff_artifact_is_prepended_to_system_prompt_when_present() {
        let tmp = tempdir().expect("tempdir");
        let workspace = tmp.path();
        let handoff_dir = workspace.join(".deepseek");
        std::fs::create_dir_all(&handoff_dir).unwrap();
        std::fs::write(
            handoff_dir.join("handoff.md"),
            "# Session handoff — prior\n\n## Active task\nFinish #32.\n\n## Open blockers\n- [ ] write the basic version\n",
        )
        .unwrap();

        let prompt = match system_prompt_for_mode_with_context(AppMode::Agent, workspace, None) {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };

        assert!(prompt.contains(HANDOFF_BLOCK_MARKER));
        assert!(prompt.contains("Finish #32."));
        assert!(prompt.contains("write the basic version"));
    }

    #[test]
    fn missing_handoff_does_not_inject_block() {
        let tmp = tempdir().expect("tempdir");
        let prompt = match system_prompt_for_mode_with_context(AppMode::Agent, tmp.path(), None) {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };
        assert!(!prompt.contains(HANDOFF_BLOCK_MARKER));
    }

    #[test]
    fn empty_handoff_file_does_not_inject_block() {
        let tmp = tempdir().expect("tempdir");
        let dir = tmp.path().join(".deepseek");
        std::fs::create_dir_all(&dir).unwrap();
        std::fs::write(dir.join("handoff.md"), "   \n\n  ").unwrap();
        let prompt = match system_prompt_for_mode_with_context(AppMode::Agent, tmp.path(), None) {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };
        assert!(!prompt.contains(HANDOFF_BLOCK_MARKER));
    }

    #[test]
    fn compose_prompt_includes_all_layers() {
        let prompt = compose_prompt(AppMode::Agent, Personality::Calm);
        // Base layer
        assert!(prompt.contains("You are DeepSeek TUI"));
        // Personality layer
        assert!(prompt.contains("Personality: Calm"));
        // Mode layer
        assert!(prompt.contains("Mode: Agent"));
        // Approval layer
        assert!(prompt.contains("Approval Policy: Suggest"));
    }

    #[test]
    fn compose_prompt_deterministic_order() {
        let prompt = compose_prompt(AppMode::Yolo, Personality::Calm);
        let base_pos = prompt.find("You are DeepSeek TUI").unwrap();
        let personality_pos = prompt.find("Personality: Calm").unwrap();
        let mode_pos = prompt.find("Mode: YOLO").unwrap();
        let approval_pos = prompt.find("Approval Policy: Auto").unwrap();

        assert!(base_pos < personality_pos);
        assert!(personality_pos < mode_pos);
        assert!(mode_pos < approval_pos);
    }

    #[test]
    fn each_mode_gets_correct_approval() {
        assert!(
            compose_prompt(AppMode::Agent, Personality::Calm).contains("Approval Policy: Suggest")
        );
        assert!(compose_prompt(AppMode::Yolo, Personality::Calm).contains("Approval Policy: Auto"));
        assert!(
            compose_prompt(AppMode::Plan, Personality::Calm).contains("Approval Policy: Never")
        );
    }

    #[test]
    fn personality_switches_correctly() {
        let calm = compose_prompt(AppMode::Agent, Personality::Calm);
        let playful = compose_prompt(AppMode::Agent, Personality::Playful);
        assert!(calm.contains("Personality: Calm"));
        assert!(playful.contains("Personality: Playful"));
        assert!(!calm.contains("Personality: Playful"));
    }

    #[test]
    fn compact_template_is_included_in_full_prompt() {
        let tmp = tempdir().expect("tempdir");
        let prompt = match system_prompt_for_mode_with_context(AppMode::Agent, tmp.path(), None) {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };
        assert!(prompt.contains("## Compaction Handoff"));
        assert!(prompt.contains("### Active task"));
        assert!(prompt.contains("### Files touched"));
        assert!(prompt.contains("### Key decisions"));
        assert!(prompt.contains("### Open blockers"));
        assert!(prompt.contains("### Next step"));
    }

    #[test]
    fn when_not_to_use_sections_present() {
        let prompt = compose_prompt(AppMode::Agent, Personality::Calm);
        assert!(prompt.contains("When NOT to use certain tools"));
        assert!(prompt.contains("### `apply_patch`"));
        assert!(prompt.contains("### `edit_file`"));
        assert!(prompt.contains("### `exec_shell`"));
        assert!(prompt.contains("### `agent_spawn`"));
        assert!(prompt.contains("### `rlm`"));
    }

    #[test]
    fn rlm_first_class_guidance_present() {
        let prompt = compose_prompt(AppMode::Agent, Personality::Calm);
        assert!(prompt.contains("RLM Is First-Class"));
        assert!(prompt.contains("independent second opinions"));
        assert!(prompt.contains("batched issue triage"));
        assert!(prompt.contains("rlm` output is advisory"));
    }

    #[test]
    fn subagent_done_sentinel_section_present() {
        let prompt = compose_prompt(AppMode::Agent, Personality::Calm);
        assert!(prompt.contains("Sub-agent completion sentinel"));
        assert!(prompt.contains("<deepseek:subagent.done>"));
        assert!(prompt.contains("Integration protocol"));
    }

    #[test]
    fn preamble_rhythm_section_present() {
        let prompt = compose_prompt(AppMode::Agent, Personality::Calm);
        assert!(prompt.contains("Preamble Rhythm"));
        assert!(prompt.contains("I'll start by reading the module structure"));
    }

    #[test]
    fn legacy_constants_still_available() {
        // Verify the old .txt constants still compile and contain expected content
        assert!(!AGENT_PROMPT.is_empty());
        assert!(!YOLO_PROMPT.is_empty());
        assert!(!PLAN_PROMPT.is_empty());
    }

    // ── Cache-prefix stability harness (#263 step 2) ───────────────────────
    //
    // These tests pin the byte-stability invariant required for DeepSeek's
    // KV prefix cache to hit: any prompt-construction surface that ends up
    // in the cached prefix must produce identical bytes given identical
    // inputs across calls.

    use crate::test_support::assert_byte_identical;

    #[test]
    fn compose_prompt_is_byte_stable_across_calls() {
        // Suspect #4 from #263: mode prompt churn within a single mode.
        // Two calls with identical (mode, personality) inputs must produce
        // identical bytes — anything else is a cache buster.
        for mode in [AppMode::Agent, AppMode::Yolo, AppMode::Plan] {
            for personality in [Personality::Calm, Personality::Playful] {
                let a = compose_prompt(mode, personality);
                let b = compose_prompt(mode, personality);
                assert_byte_identical(
                    &format!("compose_prompt(mode={mode:?}, personality={personality:?})"),
                    &a,
                    &b,
                );
            }
        }
    }

    #[test]
    fn system_prompt_for_mode_with_context_is_byte_stable_for_unchanged_workspace() {
        // Same workspace, no working_set / skills churn between calls →
        // identical bytes. This pins the most representative production
        // surface (engine.rs builds the system prompt via this fn or
        // its sibling _and_skills variant on every turn).
        let tmp = tempdir().expect("tempdir");
        let workspace = tmp.path();

        for mode in [AppMode::Agent, AppMode::Yolo, AppMode::Plan] {
            let a = match system_prompt_for_mode_with_context(mode, workspace, None) {
                SystemPrompt::Text(text) => text,
                SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
            };
            let b = match system_prompt_for_mode_with_context(mode, workspace, None) {
                SystemPrompt::Text(text) => text,
                SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
            };
            assert_byte_identical(
                &format!("system_prompt_for_mode_with_context(mode={mode:?}) on empty workspace"),
                &a,
                &b,
            );
        }
    }

    #[test]
    fn system_prompt_with_working_set_summary_is_byte_stable_for_constant_summary() {
        // The `working_set_summary` argument is the volatile surface (suspect
        // #1 in #263). Independently verifying THIS surface needs a separate
        // test in working_set.rs; here we just pin that the surrounding
        // prompt construction faithfully embeds whatever summary it's given
        // without injecting any non-determinism on its own.
        let tmp = tempdir().expect("tempdir");
        let workspace = tmp.path();
        let summary = "## Repo Working Set\nWorkspace: /tmp/x\n";

        let a = match system_prompt_for_mode_with_context(AppMode::Agent, workspace, Some(summary))
        {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };
        let b = match system_prompt_for_mode_with_context(AppMode::Agent, workspace, Some(summary))
        {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };
        assert_byte_identical(
            "system_prompt_for_mode_with_context with constant working_set summary",
            &a,
            &b,
        );
        assert!(a.contains(summary), "summary must be embedded as-is");
    }

    #[test]
    fn system_prompt_with_handoff_file_is_byte_stable_when_file_is_unchanged() {
        // Companion to the working-set stability test: if `.deepseek/handoff.md`
        // hasn't moved between two builds, the rendered prompt must produce
        // identical bytes. The handoff block is the second volatile surface
        // (the first is the working-set summary) — both land below the static
        // boundary in `system_prompt_for_mode_with_context_and_skills`.
        let tmp = tempdir().expect("tempdir");
        let workspace = tmp.path();
        let handoff_dir = workspace.join(".deepseek");
        std::fs::create_dir_all(&handoff_dir).unwrap();
        std::fs::write(
            handoff_dir.join("handoff.md"),
            "# Session handoff\n\n## Active task\nFinish #280.\n\n## Open blockers\n- [ ] none\n",
        )
        .unwrap();

        let a = match system_prompt_for_mode_with_context(AppMode::Agent, workspace, None) {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };
        let b = match system_prompt_for_mode_with_context(AppMode::Agent, workspace, None) {
            SystemPrompt::Text(text) => text,
            SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
        };
        assert_byte_identical(
            "system_prompt_for_mode_with_context with constant handoff file",
            &a,
            &b,
        );
        assert!(a.contains(HANDOFF_BLOCK_MARKER), "handoff must be embedded");
        assert!(a.contains("Finish #280."), "handoff body must be present");
    }

    #[test]
    fn handoff_and_working_set_appear_after_static_blocks() {
        // Cache-prefix invariant: the volatile blocks (handoff, working_set)
        // must come *after* the static `## Context Management` and the
        // compaction handoff template (`## Compaction Handoff`) so a churn
        // in either volatile section doesn't drag the static blocks out of
        // the cached prefix. Pre-fix ordering placed handoff between the
        // skills block and `## Context Management`, which busted the cache
        // every time `/compact` rewrote the file.
        let tmp = tempdir().expect("tempdir");
        let workspace = tmp.path();
        let handoff_dir = workspace.join(".deepseek");
        std::fs::create_dir_all(&handoff_dir).unwrap();
        std::fs::write(handoff_dir.join("handoff.md"), "# handoff body\n").unwrap();

        let summary = "## Repo Working Set\nWorkspace: /tmp/x\n";
        let prompt =
            match system_prompt_for_mode_with_context(AppMode::Agent, workspace, Some(summary)) {
                SystemPrompt::Text(text) => text,
                SystemPrompt::Blocks(_) => panic!("expected text system prompt"),
            };

        let context_pos = prompt
            .find("## Context Management")
            .expect("Context Management section present in Agent mode");
        let compact_pos = prompt
            .find("## Compaction Handoff")
            .expect("compaction handoff template present");
        let handoff_pos = prompt
            .find(HANDOFF_BLOCK_MARKER)
            .expect("handoff block present when fixture file exists");
        let working_set_pos = prompt
            .find("## Repo Working Set")
            .expect("working-set summary present when supplied");

        assert!(
            context_pos < handoff_pos,
            "## Context Management must precede the handoff block"
        );
        assert!(
            compact_pos < handoff_pos,
            "## Compaction Handoff must precede the handoff block"
        );
        assert!(
            handoff_pos < working_set_pos,
            "handoff block must precede the working-set summary (most-volatile last)"
        );
    }
}