from __future__ import annotations

from collections import deque
from typing import Iterable, List

from PySide6.QtGui import QColor, QFont, QTextCharFormat, QTextCursor, QTextOption
from PySide6.QtWidgets import QTextEdit

from ameba_control_panel.services.log_buffer import LogLine


class LogView(QTextEdit):
    """Fast-ish append-only log with selectable text and match highlighting."""

    def __init__(self, max_items: int, parent=None) -> None:
        super().__init__(parent)
        self.setReadOnly(True)
        self.setWordWrapMode(QTextOption.NoWrap)
        self.setLineWrapMode(QTextEdit.NoWrap)
        self.setHorizontalScrollBarPolicy(self.horizontalScrollBarPolicy())
        font = QFont("JetBrains Mono")
        font.setStyleHint(QFont.Monospace)
        font.setPointSize(10)
        self.setFont(font)
        self._max_items = max_items
        self._lines = deque()
        self._colors = {
            "rx": QColor("#1b5e20"),
            "tx": QColor("#0d47a1"),
            "info": QColor("#424242"),
        }
        self._match_rows: List[int] = []

    def set_colors(self, rx: str, tx: str, info: str) -> None:
        self._colors = {"rx": QColor(rx), "tx": QColor(tx), "info": QColor(info)}

    def append_lines(self, lines: Iterable[LogLine]) -> None:
        cursor = self.textCursor()
        cursor.movePosition(QTextCursor.End)
        doc = self.document()
        for line in lines:
            self._lines.append(line)
            fmt = QTextCharFormat()
            fmt.setForeground(self._colors.get(line.direction, self._colors["info"]))
            cursor.insertText(line.as_display(), fmt)
            cursor.insertBlock()
        self.setTextCursor(cursor)
        # Trim overflow blocks and mirror deque
        while len(self._lines) > self._max_items and doc.blockCount() > 0:
            self._lines.popleft()
            block = doc.firstBlock()
            cur = QTextCursor(block)
            cur.select(QTextCursor.BlockUnderCursor)
            cur.removeSelectedText()
            cur.deleteChar()
        self._apply_matches()
        self.verticalScrollBar().setValue(self.verticalScrollBar().maximum())

    def clear_log(self) -> None:
        self._lines.clear()
        self.clear()
        self._match_rows = []

    def set_matches(self, rows: List[int]) -> None:
        self._match_rows = rows
        self._apply_matches()

    def _apply_matches(self) -> None:
        extra = []
        doc = self.document()
        for row in self._match_rows:
            block = doc.findBlockByNumber(row)
            if not block.isValid():
                continue
            cursor = QTextCursor(block)
            sel = QTextEdit.ExtraSelection()
            sel.cursor = cursor
            sel.format.setBackground(QColor("#fff59d"))
            extra.append(sel)
        self.setExtraSelections(extra)

    def copy_selected(self) -> None:
        self.copy()