from __future__ import annotations

import json
import os
import re
import stat
from datetime import datetime
from typing import Annotated, Optional

import gradio as gr

from app import _log_call_end, _log_call_start, _truncate_for_log
from ._docstrings import autodoc


TOOL_SUMMARY = (
    "Browse and search the Obsidian vault in read-only mode. "
    "Actions: list, read, info, search, help. "
    "All paths resolve within the vault root."
)

HELP_TEXT = (
    "Obsidian Vault — actions and usage\n\n"
    "Root: Nymbo-Tools/Obsidian (override with OBSIDIAN_VAULT_ROOT). "
    "Absolute paths are disabled unless UNSAFE_ALLOW_ABS_PATHS=1.\n\n"
    "Actions and fields:\n"
    "- list: path='.' (default), recursive=false, show_hidden=false, max_entries=20\n"
    "- read: path, offset=0, max_chars=4000 (shows next_cursor when truncated)\n"
    "- info: path\n"
    "- search: path (note or folder), query text in the Search field, recursive=false, show_hidden=false, max_entries=20, case_sensitive=false, offset=0\n"
    "- help: show this guide\n\n"
    "Errors are returned as JSON with fields: {status:'error', code, message, path?, hint?, data?}.\n\n"
    "Examples:\n"
    "- list current: action=list, path='.'\n"
    "- read note: action=read, path='Projects/note.md', max_chars=500\n"
    "- show metadata: action=info, path='Inbox'\n"
    "- search notes: action=search, path='Projects', query='deadline', recursive=true, max_entries=100\n"
    "- case-sensitive search: action=search, query='TODO', case_sensitive=true\n"
    "- page search results: action=search, query='TODO', offset=20\n"
)


def _default_root() -> str:
    env_root = os.getenv("OBSIDIAN_VAULT_ROOT")
    if env_root and env_root.strip():
        return os.path.abspath(os.path.expanduser(env_root.strip()))
    try:
        here = os.path.abspath(__file__)
        tools_dir = os.path.dirname(os.path.dirname(here))
        return os.path.abspath(os.path.join(tools_dir, "Obsidian"))
    except Exception:
        return os.path.abspath(os.getcwd())


ROOT_DIR = _default_root()
try:
    os.makedirs(ROOT_DIR, exist_ok=True)
except Exception:
    pass
ALLOW_ABS = bool(int(os.getenv("UNSAFE_ALLOW_ABS_PATHS", "0")))


def _safe_err(exc: Exception | str) -> str:
    """Return an error string with any absolute root replaced by '/' and slashes normalized."""
    s = str(exc)
    s_norm = s.replace("\\", "/")
    root_fwd = ROOT_DIR.replace("\\", "/")
    root_variants = {ROOT_DIR, root_fwd, re.sub(r"/+", "/", root_fwd)}
    for variant in root_variants:
        if variant:
            s_norm = s_norm.replace(variant, "/")
    s_norm = re.sub(r"/+", "/", s_norm)
    return s_norm


def _err(code: str, message: str, *, path: str | None = None, hint: str | None = None, data: dict | None = None) -> str:
    payload = {
        "status": "error",
        "code": code,
        "message": message,
        "root": "/",
    }
    if path:
        payload["path"] = path
    if hint:
        payload["hint"] = hint
    if data:
        payload["data"] = data
    return json.dumps(payload, ensure_ascii=False)


def _display_path(abs_path: str) -> str:
    try:
        norm_root = os.path.normpath(ROOT_DIR)
        norm_abs = os.path.normpath(abs_path)
        common = os.path.commonpath([norm_root, norm_abs])
        if os.path.normcase(common) == os.path.normcase(norm_root):
            rel = os.path.relpath(norm_abs, norm_root)
            if rel == ".":
                return "/"
            return "/" + rel.replace("\\", "/")
    except Exception:
        pass
    return abs_path.replace("\\", "/")


def _resolve_path(path: str) -> tuple[str, str]:
    try:
        user_input = (path or ".").strip()
        raw = os.path.expanduser(user_input)
        if os.path.isabs(raw):
            if not ALLOW_ABS:
                return "", _err(
                    "absolute_path_disabled",
                    "Absolute paths are disabled in safe mode.",
                    path=raw.replace("\\", "/"),
                    hint="Use a path relative to / (e.g., Notes/index.md).",
                )
            abs_path = os.path.abspath(raw)
        else:
            abs_path = os.path.abspath(os.path.join(ROOT_DIR, raw))
        if not ALLOW_ABS:
            try:
                common = os.path.commonpath([os.path.normpath(ROOT_DIR), os.path.normpath(abs_path)])
            except Exception:
                root_cmp = os.path.normcase(os.path.normpath(ROOT_DIR))
                abs_cmp = os.path.normcase(os.path.normpath(abs_path))
                if not abs_cmp.startswith(root_cmp):
                    return "", _err(
                        "path_outside_root",
                        "Path not allowed outside root.",
                        path=user_input.replace("\\", "/"),
                        hint="Use a path under / (the vault root).",
                    )
            else:
                root_cmp = os.path.normcase(os.path.normpath(ROOT_DIR))
                common_cmp = os.path.normcase(os.path.normpath(common))
                if common_cmp != root_cmp:
                    return "", _err(
                        "path_outside_root",
                        "Path not allowed outside root.",
                        path=user_input.replace("\\", "/"),
                        hint="Use a path under / (the vault root).",
                    )
        return abs_path, ""
    except Exception as exc:
        return "", _err(
            "resolve_path_failed",
            "Failed to resolve path.",
            path=(path or ""),
            data={"error": _safe_err(exc)},
        )


def _fmt_size(num_bytes: int) -> str:
    units = ["B", "KB", "MB", "GB", "TB"]
    size = float(num_bytes)
    for unit in units:
        if size < 1024.0:
            return f"{size:.1f} {unit}"
        size /= 1024.0
    return f"{size:.1f} PB"


def _list_dir(abs_path: str, *, show_hidden: bool, recursive: bool, max_entries: int) -> str:
    lines: list[str] = []
    total = 0
    listing_display = _display_path(abs_path)
    for root, dirs, files in os.walk(abs_path):
        if not show_hidden:
            dirs[:] = [d for d in dirs if not d.startswith('.')]
            files = [f for f in files if not f.startswith('.')]
        try:
            rel_root = os.path.relpath(root, ROOT_DIR)
        except Exception:
            rel_root = root
        rel_root_disp = "/" if rel_root == "." else "/" + rel_root.replace("\\", "/")
        lines.append(f"\n📂 {rel_root_disp}")
        dirs.sort()
        files.sort()
        for d in dirs:
            p = os.path.join(root, d)
            try:
                mtime = datetime.fromtimestamp(os.path.getmtime(p)).isoformat(sep=' ', timespec='seconds')
            except Exception:
                mtime = "?"
            lines.append(f"  • [DIR] {d}    (modified {mtime})")
            total += 1
            if total >= max_entries:
                lines.append(f"\n… Truncated at {max_entries} entries.")
                return "\n".join(lines).strip()
        for f in files:
            p = os.path.join(root, f)
            try:
                size = _fmt_size(os.path.getsize(p))
                mtime = datetime.fromtimestamp(os.path.getmtime(p)).isoformat(sep=' ', timespec='seconds')
            except Exception:
                size, mtime = "?", "?"
            lines.append(f"  • {f}    ({size}, modified {mtime})")
            total += 1
            if total >= max_entries:
                lines.append(f"\n… Truncated at {max_entries} entries.")
                return "\n".join(lines).strip()
        if not recursive:
            break
    header = f"Listing of {listing_display}\nRoot: /\nEntries: {total}"
    return (header + "\n" + "\n".join(lines)).strip()


def _search_text(
    abs_path: str,
    query: str,
    *,
    recursive: bool,
    show_hidden: bool,
    max_results: int,
    case_sensitive: bool,
    start_index: int,
) -> str:
    if not os.path.exists(abs_path):
        return _err("path_not_found", f"Path not found: {_display_path(abs_path)}", path=_display_path(abs_path))

    query = query or ""
    normalized_query = query if case_sensitive else query.lower()
    if normalized_query == "":
        return _err(
            "missing_search_query",
            "Search query is required for the search action.",
            hint="Provide text in the Search field to look for.",
        )

    max_results = max(1, int(max_results) if max_results is not None else 20)
    start_index = max(0, int(start_index) if start_index is not None else 0)
    matches: list[tuple[str, int, str]] = []
    errors: list[str] = []
    files_scanned = 0
    truncated = False
    total_matches = 0

    def _should_skip(name: str) -> bool:
        return not show_hidden and name.startswith('.')

    def _handle_match(file_path: str, line_no: int, line_text: str) -> bool:
        nonlocal truncated, total_matches
        total_matches += 1
        if total_matches <= start_index:
            return False
        if len(matches) < max_results:
            snippet = line_text.strip()
            if len(snippet) > 200:
                snippet = snippet[:197] + "…"
            matches.append((_display_path(file_path), line_no, snippet))
            return False
        truncated = True
        return True

    def _search_file(file_path: str) -> bool:
        nonlocal files_scanned
        files_scanned += 1
        try:
            with open(file_path, 'r', encoding='utf-8', errors='replace') as handle:
                for line_no, line in enumerate(handle, start=1):
                    haystack = line if case_sensitive else line.lower()
                    if normalized_query in haystack:
                        if _handle_match(file_path, line_no, line):
                            return True
        except Exception as exc:
            errors.append(f"{_display_path(file_path)} ({_safe_err(exc)})")
        return truncated

    if os.path.isfile(abs_path):
        _search_file(abs_path)
    else:
        for root, dirs, files in os.walk(abs_path):
            dirs[:] = [d for d in dirs if not _should_skip(d)]
            visible_files = [f for f in files if show_hidden or not f.startswith('.')]
            for name in visible_files:
                file_path = os.path.join(root, name)
                if _search_file(file_path):
                    break
            if truncated:
                break
            if not recursive:
                break

    header_lines = [
        f"Search results for {query!r}",
        f"Scope: {_display_path(abs_path)}",
        f"Recursive: {'yes' if recursive else 'no'}, Hidden: {'yes' if show_hidden else 'no'}, Case-sensitive: {'yes' if case_sensitive else 'no'}",
        f"Start offset: {start_index}",
        f"Matches returned: {len(matches)}" + (" (truncated)" if truncated else ""),
        f"Files scanned: {files_scanned}",
    ]

    next_cursor = start_index + len(matches) if truncated else None

    if truncated:
        header_lines.append(f"Matches encountered before truncation: {total_matches}")
        header_lines.append(f"Truncated: yes — re-run with offset={next_cursor} to continue.")
        header_lines.append(f"Next cursor: {next_cursor}")
    else:
        header_lines.append(f"Total matches found: {total_matches}")
        header_lines.append("Truncated: no — end of results.")
        header_lines.append("Next cursor: None")

    if not matches:
        if total_matches > 0 and start_index >= total_matches:
            hint_limit = max(total_matches - 1, 0)
            body_lines = [
                f"No matches found at or after offset {start_index}. Total matches available: {total_matches}.",
                (f"Try a smaller offset (≤ {hint_limit})." if hint_limit >= 0 else ""),
            ]
            body_lines = [line for line in body_lines if line]
        else:
            body_lines = [
                "No matches found.",
                (f"Total matches encountered: {total_matches}." if total_matches else ""),
            ]
            body_lines = [line for line in body_lines if line]
    else:
        body_lines = [f"{idx}. {path}:{line_no}: {text}" for idx, (path, line_no, text) in enumerate(matches, start=1)]

    if errors:
        shown = errors[:5]
        body_lines.extend(["", "Warnings:"])
        body_lines.extend(shown)
        if len(errors) > len(shown):
            body_lines.append(f"… {len(errors) - len(shown)} additional files could not be read.")

    return "\n".join(header_lines) + "\n\n" + "\n".join(body_lines)


def _read_file(abs_path: str, *, offset: int, max_chars: int) -> str:
    if not os.path.exists(abs_path):
        return _err("file_not_found", f"File not found: {_display_path(abs_path)}", path=_display_path(abs_path))
    if os.path.isdir(abs_path):
        return _err(
            "is_directory",
            f"Path is a directory, not a file: {_display_path(abs_path)}",
            path=_display_path(abs_path),
            hint="Provide a file path.",
        )
    try:
        with open(abs_path, 'r', encoding='utf-8', errors='replace') as f:
            data = f.read()
    except Exception as exc:
        return _err("read_failed", "Failed to read file.", path=_display_path(abs_path), data={"error": _safe_err(exc)})
    total = len(data)
    start = max(0, min(offset, total))
    end = total if max_chars <= 0 else min(total, start + max_chars)
    chunk = data[start:end]
    next_cursor = end if end < total else None
    header = (
        f"Reading {_display_path(abs_path)}\n"
        f"Offset {start}, returned {len(chunk)} of {total}."
        + (f"\nNext cursor: {next_cursor}" if next_cursor is not None else "")
    )
    return header + "\n\n---\n\n" + chunk


def _info(abs_path: str) -> str:
    try:
        st = os.stat(abs_path)
    except Exception as exc:
        return _err("stat_failed", "Failed to stat path.", path=_display_path(abs_path), data={"error": _safe_err(exc)})
    info = {
        "path": _display_path(abs_path),
        "type": "directory" if stat.S_ISDIR(st.st_mode) else "file",
        "size": st.st_size,
        "modified": datetime.fromtimestamp(st.st_mtime).isoformat(sep=' ', timespec='seconds'),
        "created": datetime.fromtimestamp(st.st_ctime).isoformat(sep=' ', timespec='seconds'),
        "mode": oct(st.st_mode),
        "root": "/",
    }
    return json.dumps(info, indent=2)


@autodoc(summary=TOOL_SUMMARY)
def Obsidian_Vault(
    action: Annotated[str, "Operation to perform: 'list', 'read', 'info', 'search', 'help'."],
    path: Annotated[str, "Target path, relative to the vault root." ] = ".",
    query: Annotated[Optional[str], "Text to search for when action=search."] = None,
    recursive: Annotated[bool, "Recurse into subfolders when listing/searching."] = False,
    show_hidden: Annotated[bool, "Include hidden files when listing/searching."] = False,
    max_entries: Annotated[int, "Max entries to list or matches to return (for list/search)."] = 20,
    offset: Annotated[int, "Start offset when reading files."] = 0,
    max_chars: Annotated[int, "Max characters to return when reading (0 = full file)."] = 4000,
    case_sensitive: Annotated[bool, "Match case when searching text."] = False,
) -> str:
    _log_call_start(
        "Obsidian_Vault",
        action=action,
        path=path,
        query=query,
        recursive=recursive,
        show_hidden=show_hidden,
        max_entries=max_entries,
        offset=offset,
        max_chars=max_chars,
        case_sensitive=case_sensitive,
    )
    action = (action or "").strip().lower()
    if action not in {"list", "read", "info", "search", "help"}:
        result = _err(
            "invalid_action",
            "Invalid action.",
            hint="Choose from: list, read, info, search, help.",
        )
        _log_call_end("Obsidian_Vault", _truncate_for_log(result))
        return result

    if action == "help":
        result = HELP_TEXT
        _log_call_end("Obsidian_Vault", _truncate_for_log(result))
        return result

    abs_path, err = _resolve_path(path)
    if err:
        _log_call_end("Obsidian_Vault", _truncate_for_log(err))
        return err

    try:
        if action == "list":
            if not os.path.exists(abs_path):
                result = _err("path_not_found", f"Path not found: {_display_path(abs_path)}", path=_display_path(abs_path))
            else:
                result = _list_dir(abs_path, show_hidden=show_hidden, recursive=recursive, max_entries=max_entries)
        elif action == "read":
            result = _read_file(abs_path, offset=offset, max_chars=max_chars)
        elif action == "search":
            query_text = query or ""
            if query_text.strip() == "":
                result = _err(
                    "missing_search_query",
                    "Search query is required for the search action.",
                    hint="Provide text in the Search field to look for.",
                )
            else:
                result = _search_text(
                    abs_path,
                    query_text,
                    recursive=recursive,
                    show_hidden=show_hidden,
                    max_results=max_entries,
                    case_sensitive=case_sensitive,
                    start_index=offset,
                )
        else:  # info
            result = _info(abs_path)
    except Exception as exc:
        result = _err("exception", "Unhandled error during operation.", data={"error": _safe_err(exc)})

    _log_call_end("Obsidian_Vault", _truncate_for_log(result))
    return result


def build_interface() -> gr.Interface:
    return gr.Interface(
        fn=Obsidian_Vault,
        inputs=[
            gr.Radio(
                label="Action",
                choices=["list", "read", "info", "search", "help"],
                value="help",
            ),
            gr.Textbox(label="Path", placeholder=". or Notes/todo.md", max_lines=1, value="."),
            gr.Textbox(label="Search text (search)", lines=3, placeholder="Text to search for..."),
            gr.Checkbox(label="Recursive (list/search)", value=False),
            gr.Checkbox(label="Show hidden (list/search)", value=False),
            gr.Slider(minimum=10, maximum=5000, step=10, value=20, label="Max entries / matches"),
            gr.Slider(minimum=0, maximum=1_000_000, step=100, value=0, label="Offset (read/search start)"),
            gr.Slider(minimum=0, maximum=100_000, step=500, value=4000, label="Max chars (read, 0=all)"),
            gr.Checkbox(label="Case sensitive search", value=False),
        ],
        outputs=gr.Textbox(label="Result", lines=20),
        title="Obsidian Vault",
        description=(
            "<div style=\"text-align:center; overflow:hidden;\">Explore and search notes in the vault without modifying them." "</div>"
        ),
        api_description=TOOL_SUMMARY,
        flagging_mode="never",
        submit_btn="Run",
        css=(
            """
article.prose, .prose, .gr-prose {
  overflow: visible !important;
  max-height: none !important;
  -ms-overflow-style: none !important;
  scrollbar-width: none !important;
}
article.prose::-webkit-scrollbar,
.prose::-webkit-scrollbar,
.gr-prose::-webkit-scrollbar {
  display: none !important;
}
            """
        ),
    )


__all__ = ["Obsidian_Vault", "build_interface"]