"""Logging helpers for the finger dashboard."""

from __future__ import annotations

from PyQt5.QtGui import QFont, QTextCursor
from PyQt5.QtWidgets import QPlainTextEdit


class TeeStream:
    """Write to multiple text streams."""

    def __init__(self, *streams):
        self.streams = streams

    def write(self, text):
        for stream in self.streams:
            stream.write(text)

    def flush(self):
        for stream in self.streams:
            stream.flush()


class WidgetLogHandler:
    """Mirror print output into a QPlainTextEdit with a live status line at the bottom."""

    def __init__(self, widget: QPlainTextEdit):
        self.widget = widget
        self.buf = ""
        self._has_status_line = False

    def write(self, text: str):
        self.buf += text
        while "\n" in self.buf:
            line, self.buf = self.buf.split("\n", 1)
            if line:
                self._append_log_line(line)

    def flush(self):
        if self.buf:
            self._append_log_line(self.buf)
            self.buf = ""

    def set_status_line(self, text: str) -> None:
        """Update the pinned bottom line (FPS / forces) without scrolling the log."""
        text = text.rstrip("\n")
        if self._has_status_line:
            cursor = QTextCursor(self.widget.document().lastBlock())
            cursor.select(QTextCursor.BlockUnderCursor)
            cursor.insertText(text)
        else:
            self.widget.appendPlainText(text)
            self._has_status_line = True
        scrollbar = self.widget.verticalScrollBar()
        scrollbar.setValue(scrollbar.maximum())

    def clear_status_line(self) -> None:
        if not self._has_status_line:
            return
        cursor = QTextCursor(self.widget.document().lastBlock())
        cursor.select(QTextCursor.BlockUnderCursor)
        cursor.removeSelectedText()
        self._has_status_line = False

    def _append_log_line(self, line: str) -> None:
        status = None
        if self._has_status_line:
            status = self.widget.document().lastBlock().text()
            cursor = QTextCursor(self.widget.document().lastBlock())
            cursor.select(QTextCursor.BlockUnderCursor)
            cursor.removeSelectedText()
            self._has_status_line = False
        self.widget.appendPlainText(line)
        if status is not None:
            self.set_status_line(status)


def make_log_widget(config=None) -> QPlainTextEdit:
    if config is None:
        from ..layout import LOG_CONFIG

        config = LOG_CONFIG
    widget = QPlainTextEdit()
    widget.setReadOnly(True)
    widget.setMaximumBlockCount(config.max_lines)
    font = QFont(config.font_family, config.font_pt)
    font.setStyleHint(QFont.Monospace)
    widget.setFont(font)
    return widget