import re
from io import BytesIO
from typing import Any

import PIL
import PIL.Image
import cv2
import imageio.v3 as iio
from nonebot import on_message
from nonebot.adapters import Bot
from nonebot_plugin_alconna import Alconna, Args, Image, Option, UniMessage, on_alconna
import numpy

from konabot.common.nb.exc import BotExceptionMessage
from konabot.common.nb.extract_image import DepImageBytes, DepPILImage
from konabot.common.nb.match_keyword import match_keyword
from konabot.common.nb.reply_image import reply_image

# 保持不变
cmd_black_white = on_message(rule=match_keyword("黑白"))


@cmd_black_white.handle()
async def _(img: DepPILImage, bot: Bot):
    # 保持不变
    await reply_image(cmd_black_white, bot, img.convert("LA"))


# 保持不变
def parse_timestamp(tx: str) -> float | None:
    res = 0.0
    for component in tx.split(":"):
        res *= 60
        if not re.match(r"^\d+(\.\d+)?$", component):
            return
        res += float(component)
    return res


# 保持不变
cmd_giftool = on_alconna(
    Alconna(
        "giftool",
        Args["img", Image | None],
        Option("--ss", Args["start_point", str]),
        Option("--frames:v", Args["frame_count", int]),
        Option("-t", Args["length", str]),
        Option("-to", Args["end_point", str]),
        Option("--speed", Args["speed_factor", float], default=1.0, alias=["-s"]),
    )
)


@cmd_giftool.handle()
async def _(
    image: DepImageBytes,
    start_point: str | None = None,
    frame_count: int | None = None,
    length: str | None = None,
    speed_factor: float = 1.0,
    end_point: str | None = None,
):
    ss: None | float = None
    if start_point:
        ss = parse_timestamp(start_point)
        if ss is None:
            raise BotExceptionMessage("--ss 的格式不满足条件")

    t: None | float = None
    if length:
        t = parse_timestamp(length)
        if t is None:
            raise BotExceptionMessage("-t 的格式不满足条件")

    to: None | float = None
    if end_point:
        to = parse_timestamp(end_point)
        if to is None:
            raise BotExceptionMessage("-to 的格式不满足条件")

    if to is not None and ss is not None and to <= ss:
        raise BotExceptionMessage("错误：出点时间小于入点")
    if frame_count is not None and frame_count <= 0:
        raise BotExceptionMessage("错误：帧数量应该大于 0")
    if speed_factor == 0:
        raise BotExceptionMessage("错误：速度不能为 0")

    is_rev = speed_factor < 0
    speed_factor = abs(speed_factor)

    try:
        reader = iio.imread(BytesIO(image), extension=".gif", index=None)
        np_frames = list(reader)

        _pil = PIL.Image.open(BytesIO(image))
        durations: list[float] = []
        while True:
            try:
                duration = _pil.info.get('duration', 20)
                durations.append(max(duration, 20) / 1000)
                _pil.seek(_pil.tell() + 1)
            except EOFError:
                break
    except Exception:
        raise BotExceptionMessage("错误：读取 GIF 帧失败")

    ##
    # 根据开始、结束时间或者帧数量来裁取 GIF 图
    begin_time = ss or 0
    end_time = sum(durations)
    end_time = min(begin_time + (t or end_time), to or end_time, end_time)

    accumulated = 0.0
    status = 0

    sel_np_frames: list[numpy.ndarray[Any, Any]] = []
    sel_durations: list[float] = []

    for i in range(len(np_frames)):
        frame = np_frames[i]
        duration = durations[i]

        if status == 0:
            if accumulated + duration > begin_time:
                status = 1
                sel_np_frames.append(frame)
                sel_durations.append(accumulated + duration - begin_time) 
            elif accumulated + duration == begin_time:
                 status = 1
        elif status == 1:
            if accumulated + duration >= end_time:
                included_duration = end_time - accumulated
                if included_duration > 0:
                    sel_np_frames.append(frame)
                    sel_durations.append(included_duration)
                break
            sel_np_frames.append(frame)
            sel_durations.append(duration)

        accumulated += duration

    if not sel_np_frames:
        raise BotExceptionMessage("错误：裁取 GIF 帧失败（可能时间设置错误）")

    rdur_ms_unprocessed = [dur / speed_factor * 1000 for dur in sel_durations]
    rframes: list[numpy.ndarray] = []
    rdur_ms: list[int] = []

    acc_mod_20 = 0

    for i in range(len(sel_np_frames)):
        fr = sel_np_frames[i]
        du = rdur_ms_unprocessed[i]

        if du >= 20:
            rframes.append(fr)
            rdur_ms.append(int(round(du)))
            acc_mod_20 = 0
        else:
            if acc_mod_20 == 0:
                rframes.append(fr)
                rdur_ms.append(20)
                acc_mod_20 += du
            else:
                acc_mod_20 += du
                if acc_mod_20 >= 20:
                    acc_mod_20 = 0

    if len(rframes) == 1 and len(sel_np_frames) > 1:
        middle_index = max(2, len(sel_np_frames) // 2)
        rframes.append(sel_np_frames[middle_index])
        rdur_ms.append(20)

    if is_rev:
        rframes = rframes[::-1]
        rdur_ms = rdur_ms[::-1]

    output_img = BytesIO()

    if rframes:
        do_transparent = any((f.shape[2] == 4 for f in rframes))
        if do_transparent:
            rframes = [(
                f
                if f.shape[2] == 4
                else cv2.cvtColor(f, cv2.COLOR_RGB2RGBA)
            ) for f in rframes]
            kwargs = { "transparency": 0, "disposal": 2, "mode": "RGBA" }
        else:
            kwargs = {}
        try:
            iio.imwrite(
                output_img,
                rframes,
                extension=".gif",
                duration=rdur_ms,
                loop=0,
                optimize=True,
                plugin="pillow",
                **kwargs,
            )
        except Exception as e:
            raise BotExceptionMessage(f"错误：写入 GIF 失败: {e}")
    else:
        raise BotExceptionMessage("错误：没有可输出的帧")
    output_img.seek(0)
    await cmd_giftool.send(await UniMessage().image(raw=output_img).export())