"""
FileSystem Tool — Real Agent File Operations
readFile / writeFile / patchFile / deleteFile / moveFile / searchFiles / tree
"""

import asyncio
import difflib
import fnmatch
import json
import os
import re
import shutil
from pathlib import Path
from typing import Dict, List, Optional, Tuple

import structlog

log = structlog.get_logger()

WORKSPACE = os.environ.get("WORKSPACE_DIR", "/tmp/god_workspace")


class FileSystemTool:
    def __init__(self, workspace: str = WORKSPACE):
        self.workspace = workspace
        os.makedirs(workspace, exist_ok=True)

    def _safe_path(self, filename: str) -> str:
        """Resolve path safely within workspace."""
        if filename.startswith("/tmp/god_workspace") or filename.startswith(self.workspace):
            resolved = filename
        else:
            resolved = os.path.join(self.workspace, filename.lstrip("/"))
        # Security: ensure within workspace
        real = os.path.realpath(resolved)
        ws_real = os.path.realpath(self.workspace)
        if not real.startswith(ws_real):
            raise PermissionError(f"Path escape attempt: {filename}")
        return resolved

    # ─── Read ─────────────────────────────────────────────────────────────────

    async def read_file(self, filename: str, encoding: str = "utf-8") -> Dict:
        try:
            path = self._safe_path(filename)
            with open(path, "r", encoding=encoding, errors="replace") as f:
                content = f.read()
            lines = content.split("\n")
            return {
                "success": True,
                "filename": filename,
                "content": content,
                "lines": len(lines),
                "size": len(content),
                "path": path,
            }
        except FileNotFoundError:
            return {"success": False, "error": f"File not found: {filename}"}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Write ────────────────────────────────────────────────────────────────

    async def write_file(self, filename: str, content: str, encoding: str = "utf-8") -> Dict:
        try:
            path = self._safe_path(filename)
            os.makedirs(os.path.dirname(path), exist_ok=True)
            with open(path, "w", encoding=encoding) as f:
                f.write(content)
            return {
                "success": True,
                "filename": filename,
                "path": path,
                "size": len(content),
                "lines": len(content.split("\n")),
                "action": "written",
            }
        except PermissionError as e:
            return {"success": False, "error": str(e)}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Patch (smart diff apply) ─────────────────────────────────────────────

    async def patch_file(self, filename: str, old_str: str, new_str: str) -> Dict:
        """Replace old_str with new_str in file (like Cursor/Devin style edit)."""
        try:
            result = await self.read_file(filename)
            if not result["success"]:
                return result
            content = result["content"]
            if old_str not in content:
                return {
                    "success": False,
                    "error": f"Pattern not found in {filename}",
                    "hint": "Use write_file to create from scratch",
                }
            new_content = content.replace(old_str, new_str, 1)
            diff = list(difflib.unified_diff(
                content.splitlines(keepends=True),
                new_content.splitlines(keepends=True),
                fromfile=f"a/{filename}",
                tofile=f"b/{filename}",
            ))
            await self.write_file(filename, new_content)
            return {
                "success": True,
                "filename": filename,
                "action": "patched",
                "diff": "".join(diff[:50]),
                "lines_changed": len([l for l in diff if l.startswith(("+", "-")) and not l.startswith(("+++", "---"))]),
            }
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Delete ───────────────────────────────────────────────────────────────

    async def delete_file(self, filename: str) -> Dict:
        try:
            path = self._safe_path(filename)
            if os.path.isdir(path):
                shutil.rmtree(path)
                return {"success": True, "filename": filename, "action": "directory_deleted"}
            os.remove(path)
            return {"success": True, "filename": filename, "action": "deleted"}
        except FileNotFoundError:
            return {"success": False, "error": f"Not found: {filename}"}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Move / Rename ────────────────────────────────────────────────────────

    async def move_file(self, src: str, dst: str) -> Dict:
        try:
            src_path = self._safe_path(src)
            dst_path = self._safe_path(dst)
            os.makedirs(os.path.dirname(dst_path), exist_ok=True)
            shutil.move(src_path, dst_path)
            return {"success": True, "src": src, "dst": dst, "action": "moved"}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Copy ─────────────────────────────────────────────────────────────────

    async def copy_file(self, src: str, dst: str) -> Dict:
        try:
            src_path = self._safe_path(src)
            dst_path = self._safe_path(dst)
            os.makedirs(os.path.dirname(dst_path), exist_ok=True)
            shutil.copy2(src_path, dst_path)
            return {"success": True, "src": src, "dst": dst, "action": "copied"}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Search Files ─────────────────────────────────────────────────────────

    async def search_files(
        self,
        query: str,
        path: str = "",
        pattern: str = "*",
        max_results: int = 50,
    ) -> Dict:
        """Search file contents for query string."""
        try:
            base = self._safe_path(path) if path else self.workspace
            results = []
            for root, dirs, files in os.walk(base):
                dirs[:] = [d for d in dirs if not d.startswith(".") and d not in ("node_modules", "__pycache__", ".git", ".next", "dist", "build")]
                for fname in files:
                    if not fnmatch.fnmatch(fname, pattern):
                        continue
                    fpath = os.path.join(root, fname)
                    try:
                        with open(fpath, "r", encoding="utf-8", errors="replace") as f:
                            lines = f.readlines()
                        for i, line in enumerate(lines, 1):
                            if query.lower() in line.lower():
                                rel = os.path.relpath(fpath, self.workspace)
                                results.append({
                                    "file": rel,
                                    "line": i,
                                    "content": line.strip()[:200],
                                })
                                if len(results) >= max_results:
                                    break
                    except Exception:
                        continue
                if len(results) >= max_results:
                    break
            return {"success": True, "query": query, "results": results, "count": len(results)}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Tree ─────────────────────────────────────────────────────────────────

    async def tree(self, path: str = "", max_depth: int = 4) -> Dict:
        """Generate directory tree."""
        try:
            base = self._safe_path(path) if path else self.workspace
            lines = []
            self._walk_tree(base, lines, prefix="", depth=0, max_depth=max_depth)
            return {
                "success": True,
                "path": os.path.relpath(base, self.workspace) or ".",
                "tree": "\n".join(lines),
                "full_path": base,
            }
        except Exception as e:
            return {"success": False, "error": str(e)}

    def _walk_tree(self, path: str, lines: list, prefix: str, depth: int, max_depth: int):
        if depth > max_depth:
            return
        try:
            entries = sorted(os.listdir(path))
        except PermissionError:
            return
        skip = {".git", "node_modules", "__pycache__", ".next", "dist", "build", ".venv", "venv"}
        entries = [e for e in entries if e not in skip]
        for i, entry in enumerate(entries):
            full = os.path.join(path, entry)
            is_last = i == len(entries) - 1
            connector = "└── " if is_last else "├── "
            suffix = "/" if os.path.isdir(full) else ""
            lines.append(f"{prefix}{connector}{entry}{suffix}")
            if os.path.isdir(full):
                ext = "    " if is_last else "│   "
                self._walk_tree(full, lines, prefix + ext, depth + 1, max_depth)

    # ─── Make Directory ───────────────────────────────────────────────────────

    async def mkdir(self, path: str) -> Dict:
        try:
            full = self._safe_path(path)
            os.makedirs(full, exist_ok=True)
            return {"success": True, "path": path, "action": "created"}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── List Directory ───────────────────────────────────────────────────────

    async def list_dir(self, path: str = "") -> Dict:
        try:
            base = self._safe_path(path) if path else self.workspace
            entries = []
            for e in sorted(os.listdir(base)):
                full = os.path.join(base, e)
                stat = os.stat(full)
                entries.append({
                    "name": e,
                    "type": "dir" if os.path.isdir(full) else "file",
                    "size": stat.st_size,
                    "modified": int(stat.st_mtime),
                })
            return {"success": True, "path": path or ".", "entries": entries}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Grep ─────────────────────────────────────────────────────────────────

    async def grep(self, pattern: str, path: str = "", flags: str = "i") -> Dict:
        """Regex grep across workspace files."""
        try:
            base = self._safe_path(path) if path else self.workspace
            re_flags = re.IGNORECASE if "i" in flags else 0
            regex = re.compile(pattern, re_flags)
            results = []
            for root, dirs, files in os.walk(base):
                dirs[:] = [d for d in dirs if d not in {"node_modules", "__pycache__", ".git", ".next"}]
                for fname in files:
                    fpath = os.path.join(root, fname)
                    try:
                        with open(fpath, "r", encoding="utf-8", errors="replace") as f:
                            for i, line in enumerate(f, 1):
                                if regex.search(line):
                                    rel = os.path.relpath(fpath, self.workspace)
                                    results.append({"file": rel, "line": i, "content": line.strip()[:200]})
                                    if len(results) >= 100:
                                        break
                    except Exception:
                        continue
                if len(results) >= 100:
                    break
            return {"success": True, "pattern": pattern, "results": results, "count": len(results)}
        except re.error as e:
            return {"success": False, "error": f"Invalid regex: {e}"}
        except Exception as e:
            return {"success": False, "error": str(e)}

    # ─── Bulk Write (multiple files at once) ──────────────────────────────────

    async def write_files(self, files: List[Dict]) -> Dict:
        """Write multiple files at once. files = [{"filename": ..., "content": ...}]"""
        results = []
        for f in files:
            r = await self.write_file(f["filename"], f["content"])
            results.append(r)
        success_count = sum(1 for r in results if r.get("success"))
        return {
            "success": success_count == len(files),
            "total": len(files),
            "succeeded": success_count,
            "failed": len(files) - success_count,
            "results": results,
        }