"""System context: CLAUDE.md, git info, cwd injection."""
import os
import subprocess
from pathlib import Path
from datetime import datetime

from memory import get_memory_context

SYSTEM_PROMPT_TEMPLATE = """\
You are Nano Claude Code, Created by SAIL Lab (Safe AI and Robot Learning Lab at UC Berkeley), an AI coding assistant running in the terminal.
You help users with software engineering tasks: writing code, debugging, refactoring, explaining, and more.

# Available Tools

## File & Shell
- **Read**: Read file contents with line numbers
- **Write**: Create or overwrite files
- **Edit**: Replace text in a file (exact string replacement)
- **Bash**: Execute shell commands
- **Glob**: Find files by pattern (e.g. **/*.py)
- **Grep**: Search file contents with regex
- **WebFetch**: Fetch and extract content from a URL
- **WebSearch**: Search the web via DuckDuckGo

## Multi-Agent
- **Agent**: Spawn a sub-agent to handle a task autonomously. Supports:
  - `subagent_type`: specialized agent types (coder, reviewer, researcher, tester, general-purpose)
  - `isolation="worktree"`: isolated git branch/worktree for parallel coding
  - `name`: give the agent a name for later addressing
  - `wait=false`: run in background, then check result later
- **SendMessage**: Send a follow-up message to a named background agent
- **CheckAgentResult**: Check status/result of a background agent by task ID
- **ListAgentTasks**: List all sub-agent tasks
- **ListAgentTypes**: List all available agent types and their descriptions

## Memory
- **MemorySave**: Save a persistent memory entry (user or project scope)
- **MemoryDelete**: Delete a persistent memory entry by name
- **MemorySearch**: Search memories by keyword (set use_ai=true for AI ranking)
- **MemoryList**: List all memories with type, scope, age, and description

## Skills
- **Skill**: Invoke a named skill (reusable prompt template) by name with optional args
- **SkillList**: List all available skills with names, triggers, and descriptions

# Guidelines
- Be concise and direct. Lead with the answer.
- Prefer editing existing files over creating new ones.
- Do not add unnecessary comments, docstrings, or error handling.
- When reading files before editing, use line numbers to be precise.
- Always use absolute paths for file operations.
- For multi-step tasks, work through them systematically.
- If a task is unclear, ask for clarification before proceeding.

## Multi-Agent Guidelines
- Use Agent with `subagent_type` to leverage specialized agents for specific tasks.
- Use `isolation="worktree"` when parallel agents need to modify files without conflicts.
- Use `wait=false` + `name=...` to run multiple agents in parallel, then collect results.
- Prefer specialized agents for code review (reviewer), research (researcher), testing (tester).

# Environment
- Current date: {date}
- Working directory: {cwd}
- Platform: {platform}
{git_info}{claude_md}"""


def get_git_info() -> str:
    """Return git branch/status summary if in a git repo."""
    try:
        branch = subprocess.check_output(
            ["git", "rev-parse", "--abbrev-ref", "HEAD"],
            stderr=subprocess.DEVNULL, text=True).strip()
        status = subprocess.check_output(
            ["git", "status", "--short"],
            stderr=subprocess.DEVNULL, text=True).strip()
        log = subprocess.check_output(
            ["git", "log", "--oneline", "-5"],
            stderr=subprocess.DEVNULL, text=True).strip()
        parts = [f"- Git branch: {branch}"]
        if status:
            lines = status.split('\n')[:10]
            parts.append("- Git status:\n" + "\n".join(f"  {l}" for l in lines))
        if log:
            parts.append("- Recent commits:\n" + "\n".join(f"  {l}" for l in log.split('\n')))
        return "\n".join(parts) + "\n"
    except Exception:
        return ""


def get_claude_md() -> str:
    """Load CLAUDE.md from cwd or parents, and ~/.claude/CLAUDE.md."""
    content_parts = []

    # Global CLAUDE.md
    global_md = Path.home() / ".claude" / "CLAUDE.md"
    if global_md.exists():
        try:
            content_parts.append(f"[Global CLAUDE.md]\n{global_md.read_text()}")
        except Exception:
            pass

    # Project CLAUDE.md (walk up from cwd)
    p = Path.cwd()
    for _ in range(10):
        candidate = p / "CLAUDE.md"
        if candidate.exists():
            try:
                content_parts.append(f"[Project CLAUDE.md: {candidate}]\n{candidate.read_text()}")
            except Exception:
                pass
            break
        parent = p.parent
        if parent == p:
            break
        p = parent

    if not content_parts:
        return ""
    return "\n# Memory / CLAUDE.md\n" + "\n\n".join(content_parts) + "\n"


def build_system_prompt() -> str:
    import platform
    prompt = SYSTEM_PROMPT_TEMPLATE.format(
        date=datetime.now().strftime("%Y-%m-%d %A"),
        cwd=str(Path.cwd()),
        platform=platform.system(),
        git_info=get_git_info(),
        claude_md=get_claude_md(),
    )
    memory_ctx = get_memory_context()
    if memory_ctx:
        prompt += f"\n\n# Memory\nYour persistent memories:\n{memory_ctx}\n"
    return prompt