"""Unit tests for mcp-maildir indexer parsing functions.

Pure-function tests: no Qdrant, no embedding model, no network.
A throwaway Maildir is built in tmp_path for get_recent_keys().
"""

import mailbox
import os
import time
import uuid
from datetime import datetime, timezone, timedelta
from email.message import EmailMessage
from email.utils import format_datetime

import pytest

from indexer import (
    decode_mime_words,
    extract_text_from_html,
    normalize_email_address,
    parse_email_message,
    get_recent_keys,
    METADATA_COLLECTION,
)


# ---------------------------------------------------------------------------
# decode_mime_words
# ---------------------------------------------------------------------------

class TestDecodeMimeWords:
    def test_empty_and_none(self):
        assert decode_mime_words("") == ""
        assert decode_mime_words(None) == ""

    def test_plain_ascii(self):
        assert decode_mime_words("Hello World") == "Hello World"

    def test_encoded_word_utf8(self):
        # =?utf-8?q?...?= encoded word
        assert decode_mime_words("=?utf-8?q?Caf=C3=A9_au_lait?=") == "Café au lait"

    def test_encoded_word_iso8859(self):
        # decode_mime_words does not strip whitespace around the words
        assert decode_mime_words("=?iso-8859-1?q?caf=E9?=") == "café"

    def test_mixed_encoded_and_plain(self):
        assert decode_mime_words("Re: =?utf-8?q?planning_2026?=") == "Re: planning 2026"


# ---------------------------------------------------------------------------
# extract_text_from_html
# ---------------------------------------------------------------------------

class TestExtractTextFromHtml:
    def test_simple_paragraphs(self):
        html = "<html><body><p>Hello</p><p>World</p></body></html>"
        assert extract_text_from_html(html) == "Hello World"

    def test_strips_tags_and_scripts(self):
        html = "<div>Sign<span>ature</span><script>evil()</script>End</div>"
        text = extract_text_from_html(html)
        assert "evil()" not in text
        # get_text uses separator=" ", so tags become whitespace
        assert "Sign" in text and "ature" in text and "End" in text

    def test_fallback_on_invalid_content(self):
        # Garbage that would make the parser blow up should not raise
        assert extract_text_from_html(None) is None


# ---------------------------------------------------------------------------
# parse_email_message — real mailbox.Message objects (no mocks)
# ---------------------------------------------------------------------------

def build_email(
    subject="Hello",
    body="This is the body.",
    html=None,
    attachments=None,
    charset="utf-8",
):
    """Builds a real EmailMessage, optionally multipart with attachments."""
    msg = EmailMessage()
    msg["Subject"] = subject
    msg["From"] = "Alice <alice@example.com>"
    msg["To"] = "Bob <bob@example.com>"
    msg["Message-ID"] = "<build-email@example.com>"
    msg["Date"] = format_datetime(datetime(2026, 1, 15, 10, 0, 0, tzinfo=timezone.utc))

    if html:
        msg.set_content(body)
        msg.add_alternative(html, subtype="html")
    else:
        msg.set_content(body, charset=charset)

    for filename, content in (attachments or {}).items():
        payload = content if isinstance(content, bytes) else content.encode()
        msg.add_attachment(payload, maintype="application",
                           subtype="octet-stream", filename=filename)
    return msg


def build_raw_email(raw_bytes: bytes):
    """Parses raw email bytes (for exotic headers without EmailMessage helpers)."""
    import email as email_mod
    return email_mod.message_from_bytes(raw_bytes)


class TestParseEmailMessage:
    def test_plain_text_body(self):
        msg = build_email(body="Line one.\nLine two.")
        body, attachments = parse_email_message(msg)
        assert "Line one." in body and "Line two." in body
        assert attachments == []

    def test_attachments_detected_and_excluded_from_body(self):
        msg = build_email(
            body="See attached.",
            attachments={"report.pdf": b"%PDF-fake", "notes.txt": b"notes"},
        )
        body, attachments = parse_email_message(msg)
        assert attachments == ["report.pdf", "notes.txt"]
        assert "%PDF" not in body
        assert "See attached." in body

    def test_html_alternative_extracts_text(self):
        msg = build_email(
            body="Fallback plain text.",
            html="<html><body><b>Bold</b> intro</body></html>",
        )
        body, _ = parse_email_message(msg)
        assert "Bold" in body and "intro" in body

    def test_unknown_charset_falls_back_not_crash(self):
        # A payload claiming an unknown charset must not raise.
        # Built from raw bytes: EmailMessage.set_content(charset=...) would
        # reject the unknown encoding at build time, real mail does not.
        raw = (
            b"Subject: broken charset\n"
            b"From: alice@example.com\n"
            b"To: bob@example.com\n"
            b"Content-Type: text/plain; charset=x-unknown-charset\n"
            b"Content-Transfer-Encoding: 8bit\n\n"
            b"body with broken charset\n"
        )
        msg = build_raw_email(raw)
        body, attachments = parse_email_message(msg)
        # Whatever the fallback, we must get a string body and no exception
        assert isinstance(body, str)
        assert attachments == []

    def test_encoded_attachment_filename_decoded(self):
        msg = build_email(
            body="body",
            attachments={},
        )
        # Add attachment with non-ascii filename via encoded word
        msg.add_attachment(b"data", maintype="application", subtype="pdf",
                           filename="café-rapport.pdf")
        body, attachments = parse_email_message(msg)
        assert attachments == ["café-rapport.pdf"]


# ---------------------------------------------------------------------------
# normalize_email_address (indexer copy — same contract as server.py)
# ---------------------------------------------------------------------------

class TestIndexerNormalizeEmailAddress:
    def test_display_name(self):
        assert normalize_email_address("John Doe <john@example.com>") == "john@example.com"

    def test_case_and_whitespace(self):
        assert normalize_email_address("  USER@Example.COM ") == "user@example.com"

    def test_empty(self):
        assert normalize_email_address("") == ""
        assert normalize_email_address(None) == ""


# ---------------------------------------------------------------------------
# get_recent_keys — real Maildir on disk (tmp_path), mtime-driven
# ---------------------------------------------------------------------------

def make_maildir(root):
    """Opens a Maildir at root — pre-creates cur/new/tmp because mailbox.Maildir
    (Python 3.11) does not create them when adding a message."""
    for sub in ("cur", "new", "tmp"):
        os.makedirs(os.path.join(str(root), sub), exist_ok=True)
    return mailbox.Maildir(str(root), create=False)


def write_maildir_message(maildir: mailbox.Maildir, msg: EmailMessage):
    """Adds a message and returns its key."""
    return maildir.add(msg)


class TestGetRecentKeys:
    def test_recent_file_selected(self, tmp_path):
        md = make_maildir(tmp_path)
        msg = build_email()
        md.add(msg)
        md.flush()
        # mtime is now → within the window
        keys = get_recent_keys(md, days=7)
        assert len(keys) == 1

    def test_old_file_excluded(self, tmp_path):
        md = make_maildir(tmp_path)
        md.add(build_email())
        md.flush()
        # Age every file beyond the cutoff
        old = time.time() - 30 * 86400
        for path in tmp_path.rglob("*.??*"):
            if path.is_file():
                os.utime(path, (old, old))
        keys = get_recent_keys(md, days=7)
        assert len(keys) == 0

    def test_key_is_suffixless_filename(self, tmp_path):
        """Maildir keys strip the ':2,S' info suffix — get_recent_keys must match."""
        md = make_maildir(tmp_path)
        key = md.add(build_email())
        md.flush()
        keys = get_recent_keys(md, days=7)
        assert keys  # non-empty set of keys for fresh files
        assert key.split(":")[0] in keys
        for k in keys:
            assert ":" not in k