import os
from langchain_community.tools import Tool, BraveSearch, YouTubeSearchTool
from langchain_community.tools import DuckDuckGoSearchResults, GoogleSearchResults
from langchain_community.tools import WikipediaQueryRun
from langchain_community.utilities import WikipediaAPIWrapper, WolframAlphaAPIWrapper
from langchain_community.tools import WolframAlphaQueryRun
from typing import Any, Dict, List, Optional
import json
import re
from datetime import datetime, timedelta
import io  # for BytesIO

# Structured tools
try:
    from langchain_core.tools import tool
except Exception:
    def tool(*args, **kwargs):
        def _wrap(fn): return fn
        return _wrap

# Optional deps
try:
    from youtube_transcript_api import (
        YouTubeTranscriptApi,
        TranscriptsDisabled,
        NoTranscriptFound,
    )
except Exception:
    YouTubeTranscriptApi = None  # type: ignore
    TranscriptsDisabled = Exception  # type: ignore
    NoTranscriptFound = Exception  # type: ignore

try:
    from dateutil import parser as date_parser
    from dateutil.relativedelta import relativedelta
except Exception:
    date_parser = None  # type: ignore
    relativedelta = None  # type: ignore

try:
    from zoneinfo import ZoneInfo  # py>=3.9
except Exception:
    ZoneInfo = None  # type: ignore

try:
    import pandas as pd
except Exception:
    pd = None  # type: ignore

try:
    import requests
except Exception:
    requests = None  # type: ignore


def _parse_video_id(url_or_id: str) -> Optional[str]:
    s = (url_or_id or "").strip()
    if re.fullmatch(r"[0-9A-Za-z_-]{11}", s):
        return s
    try:
        from urllib.parse import urlparse, parse_qs
        u = urlparse(s)
        if u.netloc.endswith(("youtube.com", "m.youtube.com", "music.youtube.com")):
            qs = parse_qs(u.query)
            v = (qs.get("v") or [""])[0]
            if re.fullmatch(r"[0-9A-Za-z_-]{11}", v):
                return v
        if u.netloc.endswith("youtu.be"):
            vid = u.path.lstrip("/").split("/")[0]
            if re.fullmatch(r"[0-9A-Za-z_-]{11}", vid):
                return vid
    except Exception:
        pass
    return None


def _to_dt(value: str, tz: Optional[str] = None) -> datetime:
    if date_parser is not None:
        dt = date_parser.parse(value)
    else:
        try:
            dt = datetime.fromisoformat(value)
        except Exception:
            dt = datetime.strptime(value, "%Y-%m-%d")
    if tz and ZoneInfo is not None:
        try:
            z = ZoneInfo(tz)
            dt = dt.replace(
                tzinfo=z) if dt.tzinfo is None else dt.astimezone(z)
        except Exception:
            pass
    return dt


@tool("youtube_transcript", return_direct=False)
def youtube_transcript(video: str, languages: Optional[List[str]] = None, max_chars: int = 8000) -> Dict[str, Any]:
    """
    Get YouTube transcript for a video URL or ID.
    Params:
      - video: URL or 11-char video ID
      - languages: preferred languages, e.g. ["vi","en"]
      - max_chars: truncate long transcripts
    """
    if YouTubeTranscriptApi is None:
        return {"ok": False, "error": "youtube-transcript-api not installed. pip install youtube-transcript-api"}
    vid = _parse_video_id(video)
    if not vid:
        return {"ok": False, "error": "Invalid YouTube video id/url."}
    langs = languages or ["vi", "en"]
    try:
        segs = None
        try:
            segs = YouTubeTranscriptApi.get_transcript(vid, languages=langs)
        except NoTranscriptFound:
            try:
                segs = YouTubeTranscriptApi.get_transcript(
                    vid, languages=["en"])
            except Exception:
                pass
        if not segs:
            try:
                tx = YouTubeTranscriptApi.list_transcripts(vid)
                for tr in tx:
                    if tr.is_translatable and "en" in langs:
                        segs = tr.translate("en").fetch()
                        break
            except Exception:
                pass
        if not segs:
            return {"ok": False, "error": "No transcript available."}
        text = " ".join(s.get("text", "") for s in segs).strip()
        if max_chars and len(text) > max_chars:
            text = text[:max_chars] + " ...[truncated]..."
        return {"ok": True, "data": {"video_id": vid, "text": text, "segments": segs}}
    except TranscriptsDisabled:
        return {"ok": False, "error": "Transcripts are disabled for this video."}
    except Exception as e:
        return {"ok": False, "error": f"Transcript fetch failed: {e}"}


@tool("youtube_transcript_srt", return_direct=False)
def youtube_transcript_srt(video: str, languages: Optional[List[str]] = None, max_segments: Optional[int] = None) -> Dict[str, Any]:
    """
    Return the YouTube transcript as SRT captions.
    Params:
      - video: URL or 11-char video ID
      - languages: preferred languages, e.g. ["vi","en"]
      - max_segments: limit number of caption segments (optional)
    """
    try:
        # Reuse the existing transcript tool to fetch segments
        res = youtube_transcript(video=video, languages=languages, max_chars=0)
        if not res.get("ok"):
            return res

        segs = (res.get("data") or {}).get("segments") or []
        if max_segments is not None and max_segments > 0:
            segs = segs[:max_segments]

        def _srt_time(sec: float) -> str:
            sec = max(0.0, float(sec or 0.0))
            ms = int(round((sec - int(sec)) * 1000))
            s = int(sec) % 60
            m = (int(sec) // 60) % 60
            h = int(sec) // 3600
            return f"{h:02d}:{m:02d}:{s:02d},{ms:03d}"

        lines: List[str] = []
        for i, seg in enumerate(segs, 1):
            start = float(seg.get("start", 0.0))
            end = start + float(seg.get("duration", 0.0))
            text = str(seg.get("text", "")).strip()
            lines.append(str(i))
            lines.append(f"{_srt_time(start)} --> {_srt_time(end)}")
            lines.append(text)
            lines.append("")  # blank line between blocks

        srt = "\n".join(lines).strip() + ("\n" if lines else "")
        return {"ok": True, "data": {"srt": srt, "segments": len(segs)}}
    except Exception as e:
        return {"ok": False, "error": f"SRT generation failed: {e}"}


@tool("date_today", return_direct=False)
def date_today(tz: Optional[str] = None) -> Dict[str, Any]:
    """
    Return today's datetime fields.
    """
    now = datetime.now(
        ZoneInfo(tz)) if tz and ZoneInfo is not None else datetime.now()
    return {"ok": True, "data": {"iso": now.isoformat(), "date": now.date().isoformat(), "time": now.time().isoformat(timespec="seconds")}}


@tool("date_parse", return_direct=False)
def date_parse(date_str: str, tz: Optional[str] = None) -> Dict[str, Any]:
    """
    Parse a date/time string into ISO fields.
    """
    try:
        dt = _to_dt(date_str, tz)
        return {"ok": True, "data": {"iso": dt.isoformat(), "date": dt.date().isoformat(), "time": dt.time().isoformat(timespec="seconds")}}
    except Exception as e:
        return {"ok": False, "error": f"Parse failed: {e}"}


@tool("date_add", return_direct=False)
def date_add(date_str: str, days: int = 0, months: int = 0, years: int = 0, tz: Optional[str] = None) -> Dict[str, Any]:
    """
    Add/subtract days/months/years to a date/time.
    """
    try:
        dt = _to_dt(date_str, tz)
        if relativedelta is not None:
            dt2 = dt + relativedelta(days=days, months=months, years=years)
        else:
            if months or years:
                return {"ok": False, "error": "Month/year arithmetic needs python-dateutil. pip install python-dateutil"}
            dt2 = dt + timedelta(days=days)
        return {"ok": True, "data": {"iso": dt2.isoformat(), "date": dt2.date().isoformat(), "time": dt2.time().isoformat(timespec="seconds")}}
    except Exception as e:
        return {"ok": False, "error": f"Add failed: {e}"}


@tool("date_diff", return_direct=False)
def date_diff(start: str, end: str, unit: str = "days", tz: Optional[str] = None) -> Dict[str, Any]:
    """
    Difference between two date/times. unit: days|hours|minutes|seconds.
    """
    try:
        d1 = _to_dt(start, tz)
        d2 = _to_dt(end, tz)
        seconds = (d2 - d1).total_seconds()
        unit = (unit or "days").lower()
        if unit == "seconds":
            value = seconds
        elif unit == "minutes":
            value = seconds / 60
        elif unit == "hours":
            value = seconds / 3600
        else:
            unit = "days"
            value = seconds / 86400
        return {"ok": True, "data": {"value": value, "unit": unit}}
    except Exception as e:
        return {"ok": False, "error": f"Diff failed: {e}"}


@tool("next_weekday", return_direct=False)
def next_weekday(date_str: str, weekday: int, include_today: bool = False, tz: Optional[str] = None) -> Dict[str, Any]:
    """
    Next date matching weekday (0=Mon..6=Sun).
    """
    try:
        base = _to_dt(date_str, tz).date()
        wd = int(weekday) % 7
        delta = (wd - base.weekday()) % 7
        if delta == 0 and not include_today:
            delta = 7
        target = base + timedelta(days=delta)
        return {"ok": True, "data": {"date": target.isoformat(), "weekday": wd}}
    except Exception as e:
        return {"ok": False, "error": f"next_weekday failed: {e}"}


@tool("date_format", return_direct=False)
def date_format(date_str: str, fmt: str = "%Y-%m-%d %H:%M:%S", tz: Optional[str] = None) -> Dict[str, Any]:
    """
    Format a date/time string with strftime.
    """
    try:
        dt = _to_dt(date_str, tz)
        return {"ok": True, "data": {"formatted": dt.strftime(fmt)}}
    except Exception as e:
        return {"ok": False, "error": f"Format failed: {e}"}


@tool("read_excel", return_direct=False)
def read_excel(path_or_url: str, sheet: Optional[str] = None, nrows: int = 100, usecols: Optional[str] = None, header: Optional[int] = 0) -> Dict[str, Any]:
    """
    Read a worksheet from an Excel file (.xlsx/.xls/.xlsm) from a local path or HTTP(S) URL.
    Params:
      - path_or_url: local file path or URL.
      - sheet: sheet name or 0-based index (default: first sheet).
      - nrows: max number of rows to return (default: 100).
      - usecols: Excel-style column selection, e.g., 'A:D' or 'A,C:E'.
      - header: row index to use as header (default: 0). Use None for no header.
    """
    if pd is None:
        return {"ok": False, "error": "pandas not installed. pip install pandas openpyxl"}
    src = (path_or_url or "").strip()
    if not src:
        return {"ok": False, "error": "Missing path_or_url"}
    try:
        data_src: Any
        if re.match(r"^https?://", src, re.I):
            if requests is None:
                return {"ok": False, "error": "requests not installed for URL fetching. pip install requests"}
            resp = requests.get(src, timeout=30)
            resp.raise_for_status()
            data_src = io.BytesIO(resp.content)
        else:
            if not os.path.exists(src):
                return {"ok": False, "error": f"File not found: {src}"}
            data_src = src

        sheet_name = 0 if sheet is None else sheet
        df = pd.read_excel(
            data_src,
            sheet_name=sheet_name,
            nrows=None if (nrows is None or nrows <= 0) else nrows,
            usecols=usecols,
            header=header
        )

        if isinstance(df, dict):  # safety if engine returns multiple sheets
            first_key = next(iter(df.keys()))
            df = df[first_key]
            sheet_used = first_key
        else:
            sheet_used = sheet_name

        if nrows and nrows > 0:
            df = df.head(nrows)

        columns = [str(c) for c in df.columns.tolist()]
        records = df.to_dict(orient="records")
        return {
            "ok": True,
            "data": {
                "sheet": sheet_used,
                "columns": columns,
                "records": records,
                "info": {"rows": len(records), "cols": len(columns)}
            }
        }
    except Exception as e:
        return {"ok": False, "error": "Excel read failed: {}".format(e)}


@tool("read_text", return_direct=False)
def read_text(path_or_url: str, max_chars: int = 20000, encoding: Optional[str] = None) -> Dict[str, Any]:
    """
    Read a text file from a local path or HTTP(S) URL.
    Params:
      - path_or_url: local file path or URL.
      - max_chars: maximum characters to return (default: 20000).
      - encoding: optional text encoding override; if omitted, try to detect.
    """
    src = (path_or_url or "").strip()
    if not src:
        return {"ok": False, "error": "Missing path_or_url"}

    try:
        text: str = ""
        used_encoding: str = "utf-8"

        if re.match(r"^https?://", src, re.I):
            if requests is None:
                return {"ok": False, "error": "requests not installed for URL fetching. pip install requests"}
            resp = requests.get(src, timeout=30)
            resp.raise_for_status()
            used_encoding = encoding or resp.encoding or getattr(
                resp, "apparent_encoding", None) or "utf-8"
            text = resp.content.decode(used_encoding, errors="replace")
        else:
            if not os.path.exists(src):
                return {"ok": False, "error": f"File not found: {src}"}
            enc_candidates = [encoding] if encoding else [
                "utf-8", "utf-16", "utf-16-le", "utf-16-be", "latin-1"]
            for enc_try in enc_candidates:
                try:
                    with open(src, "r", encoding=enc_try, errors="strict") as f:
                        text = f.read()
                        used_encoding = enc_try or "utf-8"
                        break
                except Exception:
                    continue
            else:
                with open(src, "rb") as f:
                    raw = f.read()
                used_encoding = "latin-1"
                text = raw.decode(used_encoding, errors="replace")

        truncated = False
        if max_chars and max_chars > 0 and len(text) > max_chars:
            text = text[:max_chars] + " ...[truncated]..."
            truncated = True

        return {
            "ok": True,
            "data": {
                "path": src,
                "encoding": used_encoding,
                "truncated": truncated,
                "length": len(text),
                "text": text,
            },
        }
    except Exception as e:
        return {"ok": False, "error": f"Text read failed: {e}"}


def get_tools():
    """
    Returns a list of tools that can be used by the agent.
    """
    wikipedia_api_wrapper = WikipediaAPIWrapper()
    tools = [
        Tool(
            name="YouTubeSearch",
            func=YouTubeSearchTool().run,
            description="Search YouTube for videos."
        ),
        Tool(
            name="DuckDuckGoSearch",
            func=DuckDuckGoSearchResults().run,
            description="Search the web using DuckDuckGo."
        ),
        # Tool(
        #     name="GoogleSearch",
        #     func=GoogleSearchResults().run,
        #     description="Search the web using Google."
        # ),
        Tool(
            name="WikipediaQuery",
            func=WikipediaQueryRun(api_wrapper=wikipedia_api_wrapper).run,
            description="Query Wikipedia for information."
        ),
        # Tool(
        #     name="WolframAlphaQuery",
        #     func=WolframAlphaQueryRun().run,
        #     description="Query Wolfram Alpha for computational knowledge."
        # )
    ]
    # Add structured tools (LangChain @tool)
    tools.extend([
        youtube_transcript,
        date_today,
        date_parse,
        date_add,
        date_diff,
        next_weekday,
        date_format,
        read_text,
        read_excel,
        youtube_transcript_srt,  # new
    ])
    return tools