from __future__ import annotations

import html
import re

from pathlib import Path
from urllib.parse import quote

from Core import ResolvePath
from Explorer import ClassifyFile, GetDirectoryNoteInfo
from Locks import IsPathAccessible
from Portals import ResolvePortals
from Preview import GetMimeType, ReadTextFile, TextFileTypes


DescriptionExcerptLength = 200

DefaultDescriptions = {
    "directory": "A directory on SaraView.",
    "video": "A video on SaraView.",
    "image": "An image on SaraView.",
    "note": "A note on SaraView.",
    "file": "A file on SaraView.",
}


def _StripMarkdownForExcerpt(Text: str) -> str:
    Cleaned = re.sub(r"[#*_`>~\[\]]", "", Text)
    Cleaned = re.sub(r"\s+", " ", Cleaned).strip()
    return Cleaned[:DescriptionExcerptLength]


def _DescribeTextFile(RootName: str, RelativePath: str, FilePath: Path, Fallback: str) -> str:
    try:
        Content = ReadTextFile(FilePath)
        Resolved = ResolvePortals(RootName, RelativePath, Content, "", [])
        Excerpt = _StripMarkdownForExcerpt(Resolved)
        return Excerpt or Fallback
    except (OSError, UnicodeDecodeError):
        return Fallback


def _MetaTag(Property: str, Content: str) -> str:
    return f'<meta property="{html.escape(Property)}" content="{html.escape(Content)}" />'


def BuildOgTags(RootName: str, RelativePath: str, IsDirectoryUrl: bool, BaseUrl: str) -> str | None:
    if not IsPathAccessible(RootName, RelativePath, "", []):
        return None

    try:
        EntryPath = ResolvePath(RootName, RelativePath)
    except ValueError:
        return None

    if not EntryPath.exists():
        return None

    EncodedPath = "/".join(quote(Segment) for Segment in RelativePath.split("/") if Segment)
    PageUrl = f"{BaseUrl}/{quote(RootName)}/{EncodedPath}{'/' if IsDirectoryUrl else ''}"
    Tags = [_MetaTag("og:url", PageUrl)]

    if EntryPath.is_dir():
        NoteInfo = GetDirectoryNoteInfo(EntryPath)
        Description = DefaultDescriptions["directory"]

        if NoteInfo is not None and NoteInfo["FileType"] in TextFileTypes:
            NotePath = EntryPath / NoteInfo["Name"]
            NoteRelativePath = f"{RelativePath}/{NoteInfo['Name']}" if RelativePath else NoteInfo["Name"]
            Description = _DescribeTextFile(
                RootName, NoteRelativePath, NotePath, DefaultDescriptions["directory"]
            )

        Tags.append(_MetaTag("og:title", EntryPath.name))
        Tags.append(_MetaTag("og:description", Description))
        Tags.append(_MetaTag("og:type", "website"))
        return "\n".join(Tags)

    FileType = ClassifyFile(EntryPath)
    MediaUrl = f"{BaseUrl}/public/media/{quote(RootName)}/{EncodedPath}"

    Tags.append(_MetaTag("og:title", EntryPath.name))

    if FileType == "video":
        Tags.append(_MetaTag("og:type", "video.other"))
        Tags.append(_MetaTag("og:video", MediaUrl))
        Tags.append(_MetaTag("og:video:url", MediaUrl))
        Tags.append(_MetaTag("og:video:secure_url", MediaUrl))
        Tags.append(_MetaTag("og:video:type", GetMimeType(EntryPath)))
        Tags.append(_MetaTag("og:description", DefaultDescriptions["video"]))
    elif FileType == "image":
        Tags.append(_MetaTag("og:type", "website"))
        Tags.append(_MetaTag("og:image", MediaUrl))
        Tags.append(_MetaTag("og:image:type", GetMimeType(EntryPath)))
        Tags.append(_MetaTag("og:description", DefaultDescriptions["image"]))
    elif FileType in TextFileTypes:
        Description = _DescribeTextFile(RootName, RelativePath, EntryPath, DefaultDescriptions["note"])
        Tags.append(_MetaTag("og:type", "article"))
        Tags.append(_MetaTag("og:description", Description))
    else:
        Tags.append(_MetaTag("og:type", "website"))
        Tags.append(_MetaTag("og:description", DefaultDescriptions["file"]))

    return "\n".join(Tags)