"""Render cleaned messages into page_content, dense_content, sparse_content."""

import datetime

from .cleaning import CleanedMessage


def _format_time(ts: int) -> str:
    try:
        return datetime.datetime.fromtimestamp(ts, tz=datetime.timezone.utc).strftime("%Y-%m-%d %H:%M")
    except (OSError, OverflowError, ValueError):
        return str(ts)


def render_page_content(msg: CleanedMessage) -> str:
    """Human-readable text for the chunk payload."""
    lines: list[str] = []

    prefix = f"{msg.sender_id}:"
    if msg.text:
        lines.append(f"{prefix} {msg.text}")
    elif not msg.parts and not msg.member_event_text:
        lines.append(prefix)

    for part in msg.parts:
        lines.append(part["text"])

    if msg.member_event_text:
        lines.append(msg.member_event_text)

    for fi in msg.file_info:
        name = fi.get("name") or fi.get("url") or "file"
        lines.append(f"[attachment: {name}]")

    return "\n".join(lines)


def render_dense_content(msg: CleanedMessage) -> str:
    """Text optimized for semantic dense embedding: role markers + full context."""
    lines: list[str] = []
    ts = _format_time(msg.time)

    header_parts = [f"[{ts}]", f"sender:{msg.sender_id}"]
    if msg.is_forward:
        header_parts.append("type:forward")
    if msg.is_quote:
        header_parts.append("type:quote")
    if msg.is_system:
        header_parts.append("type:system")
    if msg.thread_sn:
        header_parts.append(f"thread:{msg.thread_sn}")
    lines.append(" ".join(header_parts))

    if msg.text:
        lines.append(msg.text)

    for part in msg.parts:
        lines.append(part["text"])

    if msg.member_event_text:
        lines.append(msg.member_event_text)

    for fi in msg.file_info:
        fi_parts = []
        if fi.get("name"):
            fi_parts.append(fi["name"])
        if fi.get("mime"):
            fi_parts.append(fi["mime"])
        if fi.get("url"):
            fi_parts.append(fi["url"])
        if fi_parts:
            lines.append(f"[file: {' '.join(fi_parts)}]")

    if msg.mentions:
        lines.append("mentions: " + ", ".join(msg.mentions))

    return "\n".join(lines)


def render_sparse_content(msg: CleanedMessage) -> str:
    """Keyword-heavy text for sparse/BM25 embedding."""
    tokens: list[str] = []

    tokens.append(msg.sender_id)
    tokens.extend(msg.mentions)

    if msg.text:
        tokens.append(msg.text)

    for part in msg.parts:
        tokens.append(part["text"])

    if msg.member_event_text:
        tokens.append(msg.member_event_text)

    for fi in msg.file_info:
        for key in ("name", "mime", "url"):
            val = fi.get(key)
            if val:
                tokens.append(val)

    return " ".join(tokens)