import math
import re
import threading
import time
from typing import List, Optional

from PyQt6.QtGui import QBrush, QColor, QPen

from highlight_regex import HighlightRegex
from line import Line
import os
from settings import Settings


class LogFileModel:
    _query_highlight: Optional[HighlightRegex] = None

    def __init__(self, file: str, settings: Settings):
        self.settings = settings
        self._file = os.path.realpath(file)
        self._lock = threading.RLock()

        self.highlights = [
            HighlightRegex(
                re.compile("ERROR"),
                brush=QBrush(QColor(220, 112, 122)),
                pen=QPen(QColor(0, 0, 0)),
                brush_full_line=QBrush(QColor(255, 112, 122))
            )
        ]

    def get_file(self):
        return self._file

    def __str__(self):
        return self._file

    def get_query_highlight(self):
        return self._query_highlight

    def set_query_highlight(self, regex: Optional[re.Pattern] = None):
        if regex:
            self._query_highlight = HighlightRegex(
                regex,
                brush=QBrush(QColor(255, 255, 0))
            )
        else:
            self._query_highlight = None

    def get_tab_name(self):
        file_name = os.path.basename(self._file)
        if len(file_name) > 35:
            file_name = file_name[:15] + "..." + file_name[-15:]
        return file_name

    def read_range(self, start_byte: int, end_byte: int):
        with self._lock:
            with open(self._file, 'rb') as f:
                f.seek(start_byte)
                bytes = f.read(end_byte - start_byte)
                return bytes.decode("utf8", errors="ignore")

    def data(self, byte_offset, scroll_lines, lines) -> List[Line]:
        # print("data(%s, %s, %s)" % (byte_offset, scroll_lines, lines))
        lines_before_offset: List[Line] = []
        lines_after_offset: List[Line] = []
        lines_to_find = lines + abs(scroll_lines)
        lines_to_return = math.ceil(lines)

        # start = time.time()
        with self._lock:
            # print("data lock acquision %.4f" % (time.time() -start))
            # TODO handle lines longer than 4096 bytes
            # TODO abort file open after a few secons: https://docs.python.org/3/library/signal.html#example
            with open(self._file, 'rb') as f:
                offset = min(byte_offset, self.byte_count())
                offset = max(0, offset - self.settings.max_line_length())

                # print("offset: %s" % (offset))

                eof_reached = True
                f.seek(offset)
                while l := f.readline():
                    new_offset = f.tell()
                    line = Line(offset, new_offset,
                                l.decode("utf8", errors="ignore").replace("\r", "").replace("\n", ""))
                    # print("%s %s" %(line.byte_offset(), line.line()))
                    if offset < byte_offset:
                        lines_before_offset.append(line)
                    else:
                        lines_after_offset.append(line)
                    offset = f.tell()
                    if len(lines_after_offset) >= lines_to_find:
                        eof_reached = False
                        break

            all_lines = lines_before_offset + lines_after_offset
            start = max(0, len(lines_before_offset) + scroll_lines)
            if start + lines_to_return - 1 < len(all_lines):
                result = all_lines[start:start + lines_to_return]
            else:
                result = all_lines[-lines_to_return + 1:]

            # print("returning %s lines" % (len(result)))
            return result

    def byte_count(self) -> int:
        return os.stat(self._file).st_size

    def write_line(self, line: str):
        with open(self._file, 'a+b') as f:
            f.write(line.encode("utf8"))
            if not line.endswith("\n"):
                f.write("\n".encode("utf8"))

    def truncate(self):
        with open(self._file, 'a') as f:
            f.truncate(0)