#!/usr/bin/env python3
"""
Caveman Memory Compression Orchestrator

Usage:
    python scripts/compress.py <filepath>
"""

import os
import re
import shutil
import subprocess
import sys
from pathlib import Path
from typing import List

OUTER_FENCE_REGEX = re.compile(
    r"\A\s*(`{3,}|~{3,})[^\n]*\n(.*)\n\1\s*\Z", re.DOTALL
)

# YAML frontmatter: starts at file start with --- on its own line, ends with --- on its own line.
# Captures the entire block (including delimiters and trailing newline) and the body after.
FRONTMATTER_REGEX = re.compile(
    r"\A(---\r?\n.*?\r?\n---\r?\n)(.*)", re.DOTALL
)


def split_frontmatter(text: str):
    """Split YAML frontmatter from body. Returns (frontmatter, body).

    Memory files (and many other markdown docs) start with a YAML frontmatter
    block delimited by `---` lines. The compression LLM has a habit of stripping
    or rewriting these despite preserve-structure rules in the prompt — so we
    surgically remove the frontmatter before compression and prepend it back
    verbatim to the output. Files without frontmatter pass through unchanged.
    """
    m = FRONTMATTER_REGEX.match(text)
    if m:
        return m.group(1), m.group(2)
    return "", text

# Filenames and paths that almost certainly hold secrets or PII. Compressing
# them ships raw bytes to the Anthropic API — a third-party data boundary that
# developers on sensitive codebases cannot cross. detect.py already skips .env
# by extension, but credentials.md / secrets.txt / ~/.aws/credentials would
# slip through the natural-language filter. This is a hard refuse before read.
SENSITIVE_BASENAME_REGEX = re.compile(
    r"(?ix)^("
    r"\.env(\..+)?"
    r"|\.netrc"
    r"|credentials(\..+)?"
    r"|secrets?(\..+)?"
    r"|passwords?(\..+)?"
    r"|id_(rsa|dsa|ecdsa|ed25519)(\.pub)?"
    r"|authorized_keys"
    r"|known_hosts"
    r"|.*\.(pem|key|p12|pfx|crt|cer|jks|keystore|asc|gpg)"
    r")$"
)

SENSITIVE_PATH_COMPONENTS = frozenset({".ssh", ".aws", ".gnupg", ".kube", ".docker"})

SENSITIVE_NAME_TOKENS = (
    "secret", "credential", "password", "passwd",
    "apikey", "accesskey", "token", "privatekey",
)


def backup_dir_for(filepath: Path) -> Path:
    """Resolve the out-of-tree backup directory for a given source file.

    Backups must live OUTSIDE the source directory so skill auto-loaders
    (Claude Code rules/, opencode instructions/, etc.) stop re-ingesting the
    `.original.md` copies as live files. Base dir is platform-aware:
      - Windows: %LOCALAPPDATA%\\caveman-compress\\backups
      - else:    $XDG_DATA_HOME/caveman-compress/backups if set,
                 else ~/.local/share/caveman-compress/backups

    The source file's parent-dir name is mirrored under the base to reduce
    cross-project collisions (e.g. two `task.md` files in different repos).
    """
    if os.name == "nt" or sys.platform == "win32":
        local_appdata = os.environ.get("LOCALAPPDATA")
        base = Path(local_appdata) if local_appdata else Path.home() / "AppData" / "Local"
        base = base / "caveman-compress" / "backups"
    else:
        xdg = os.environ.get("XDG_DATA_HOME")
        base = Path(xdg) if xdg else Path.home() / ".local" / "share"
        base = base / "caveman-compress" / "backups"
    return base / filepath.parent.name


def is_sensitive_path(filepath: Path) -> bool:
    """Heuristic denylist for files that must never be shipped to a third-party API."""
    name = filepath.name
    if SENSITIVE_BASENAME_REGEX.match(name):
        return True
    lowered_parts = {p.lower() for p in filepath.parts}
    if lowered_parts & SENSITIVE_PATH_COMPONENTS:
        return True
    # Normalize separators so "api-key" and "api_key" both match "apikey".
    lower = re.sub(r"[_\-\s.]", "", name.lower())
    return any(tok in lower for tok in SENSITIVE_NAME_TOKENS)


def strip_llm_wrapper(text: str) -> str:
    """Strip outer ```markdown ... ``` fence when it wraps the entire output."""
    m = OUTER_FENCE_REGEX.match(text)
    if m:
        return m.group(2)
    return text

from .detect import should_compress
from .validate import validate

MAX_RETRIES = 2


# ---------- Claude Calls ----------


def call_claude(prompt: str) -> str:
    """Send a prompt to Claude.

    Prefers the Anthropic SDK when ANTHROPIC_API_KEY is set; otherwise falls
    back to the ``claude --print`` CLI (which handles desktop auth).

    On Windows the CLI subprocess decoding defaults to the system codepage
    (cp1251 / cp1252) and crashes on UTF-8 output — see issue #152. Pinning
    ``encoding="utf-8"`` with ``errors="replace"`` matches the CLI's actual
    native I/O and prevents the UnicodeDecodeError before validation can
    report. Windows users with non-ASCII content can also set
    ``ANTHROPIC_API_KEY`` to route through the SDK and skip the subprocess.
    """
    api_key = os.environ.get("ANTHROPIC_API_KEY")
    if api_key:
        try:
            import anthropic

            client = anthropic.Anthropic(api_key=api_key)
            msg = client.messages.create(
                model=os.environ.get("CAVEMAN_MODEL", "claude-sonnet-4-5"),
                max_tokens=8192,
                messages=[{"role": "user", "content": prompt}],
            )
            return strip_llm_wrapper(msg.content[0].text.strip())
        except ImportError:
            pass  # anthropic not installed, fall back to CLI
    # Fallback: use claude CLI (handles desktop auth).
    # Resolve binary via shutil.which so Windows .cmd/.bat shims (e.g.
    # %APPDATA%\npm\claude.CMD) work without shell=True. On POSIX,
    # shutil.which returns the same absolute path as the implicit lookup,
    # so this is a no-op there. Falls back to bare "claude" if not found
    # on PATH so subprocess raises a clear FileNotFoundError.
    claude_bin = shutil.which("claude") or "claude"
    try:
        result = subprocess.run(
            [claude_bin, "--print"],
            input=prompt,
            text=True,
            capture_output=True,
            check=True,
            encoding="utf-8",
            errors="replace",
        )
        return strip_llm_wrapper(result.stdout.strip())
    except subprocess.CalledProcessError as e:
        raise RuntimeError(f"Claude call failed:\n{e.stderr}")


def build_compress_prompt(original: str) -> str:
    return f"""
Compress this markdown into caveman format.

STRICT RULES:
- Do NOT modify anything inside ``` code blocks
- Do NOT modify anything inside inline backticks
- Preserve ALL URLs exactly
- Preserve ALL headings exactly
- Preserve file paths and commands
- Return ONLY the compressed markdown body — do NOT wrap the entire output in a ```markdown fence or any other fence. Inner code blocks from the original stay as-is; do not add a new outer fence around the whole file.

Only compress natural language.

TEXT:
{original}
"""


def build_fix_prompt(original: str, compressed: str, errors: List[str]) -> str:
    errors_str = "\n".join(f"- {e}" for e in errors)
    return f"""You are fixing a caveman-compressed markdown file. Specific validation errors were found.

CRITICAL RULES:
- DO NOT recompress or rephrase the file
- ONLY fix the listed errors — leave everything else exactly as-is
- The ORIGINAL is provided as reference only (to restore missing content)
- Preserve caveman style in all untouched sections

ERRORS TO FIX:
{errors_str}

HOW TO FIX:
- Missing URL: find it in ORIGINAL, restore it exactly where it belongs in COMPRESSED
- Code block mismatch: find the exact code block in ORIGINAL, restore it in COMPRESSED
- Heading mismatch: restore the exact heading text from ORIGINAL into COMPRESSED
- Do not touch any section not mentioned in the errors

ORIGINAL (reference only):
{original}

COMPRESSED (fix this):
{compressed}

Return ONLY the fixed compressed file. No explanation.
"""


# ---------- Core Logic ----------


def compress_file(filepath: Path) -> bool:
    # Resolve and validate path
    filepath = filepath.resolve()
    MAX_FILE_SIZE = 500_000  # 500KB
    if not filepath.exists():
        raise FileNotFoundError(f"File not found: {filepath}")
    if filepath.stat().st_size > MAX_FILE_SIZE:
        raise ValueError(f"File too large to compress safely (max 500KB): {filepath}")

    # Refuse files that look like they contain secrets or PII. Compressing ships
    # the raw bytes to the Anthropic API — a third-party boundary — so we fail
    # loudly rather than silently exfiltrate credentials or keys. Override is
    # intentional: the user must rename the file if the heuristic is wrong.
    if is_sensitive_path(filepath):
        raise ValueError(
            f"Refusing to compress {filepath}: filename looks sensitive "
            "(credentials, keys, secrets, or known private paths). "
            "Compression sends file contents to the Anthropic API. "
            "Rename the file if this is a false positive."
        )

    print(f"Processing: {filepath}")

    if not should_compress(filepath):
        print("Skipping (not natural language)")
        return False

    original_text = filepath.read_text(errors="ignore")
    # Store backup outside the source directory so skill auto-loaders don't
    # re-ingest the `.original.md` copy as a live file. Mirror the source's
    # parent-dir name + stem under a platform-aware base to reduce collisions.
    backup_dir = backup_dir_for(filepath)
    backup_dir.mkdir(parents=True, exist_ok=True)
    backup_path = backup_dir / (filepath.stem + ".original.md")

    if not original_text.strip():
        print("❌ Refusing to compress: file is empty or whitespace-only.")
        return False

    # Check if backup already exists to prevent accidental overwriting
    if backup_path.exists():
        print(f"⚠️ Backup file already exists: {backup_path}")
        print("The original backup may contain important content.")
        print("Aborting to prevent data loss. Please remove or rename the backup file if you want to proceed.")
        return False

    # Split YAML frontmatter off before compression. Claude tends to strip or
    # rewrite frontmatter despite preserve-structure rules; we keep it verbatim
    # by removing it from the input and re-prepending it to the output.
    frontmatter, body = split_frontmatter(original_text)
    if frontmatter:
        print(f"Detected YAML frontmatter ({len(frontmatter)} chars) — preserving verbatim")

    if not body.strip():
        print("❌ Refusing to compress: body is empty after frontmatter removal.")
        return False

    # Step 1: Compress (body only, frontmatter excluded)
    print("Compressing with Claude...")
    compressed_body = call_claude(build_compress_prompt(body))

    if compressed_body is None or not compressed_body.strip():
        print("❌ Compression aborted: Claude returned an empty response.")
        print("   Original file is untouched (no backup created).")
        return False

    # Compare the BODY (not the whole file) — frontmatter is preserved verbatim
    # and would never change, so identity must be judged on the compressible part.
    if compressed_body.strip() == body.strip():
        print("❌ Compression aborted: output is identical to input.")
        print("   Likely causes: Claude refused, returned the prompt verbatim, or the file is")
        print("   already in caveman form. Original file is untouched (no backup created).")
        return False

    # Reassemble: frontmatter (verbatim) + compressed body
    compressed = frontmatter + compressed_body

    # Save original as backup, then verify the backup readback before
    # touching the input file. If the filesystem dropped bytes (encoding,
    # antivirus, disk full), unlink the bad backup and abort instead of
    # leaving the user with a corrupt backup + compressed primary.
    backup_path.write_text(original_text)
    backup_readback = backup_path.read_text(errors="ignore")
    if backup_readback != original_text:
        print(f"❌ Backup write verification failed: {backup_path}")
        print("   In-memory original differs from on-disk backup. Aborting before touching the input file.")
        try:
            backup_path.unlink()
        except OSError:
            pass
        return False
    filepath.write_text(compressed)

    # Step 2: Validate + Retry
    for attempt in range(MAX_RETRIES):
        print(f"\nValidation attempt {attempt + 1}")

        result = validate(backup_path, filepath)

        if result.is_valid:
            print("Validation passed")
            break

        print("❌ Validation failed:")
        for err in result.errors:
            print(f"   - {err}")

        if attempt == MAX_RETRIES - 1:
            # Restore original on failure
            filepath.write_text(original_text)
            backup_path.unlink(missing_ok=True)
            print("❌ Failed after retries — original restored")
            return False

        print("Fixing with Claude...")
        compressed = call_claude(
            build_fix_prompt(original_text, compressed, result.errors)
        )
        filepath.write_text(compressed)

    return True