from __future__ import annotations

from dataclasses import dataclass
from typing import Dict

import cv2
import numpy as np
from PIL import ImageGrab

from app.infrastructure.service.logging.log_service import log_event, new_trace_id
from app.infrastructure.service.wechat.config import (
    CHAT_CAPTURE_HEIGHT,
    CHAT_CAPTURE_LEFT_OFFSET,
    CHAT_CAPTURE_TOP_OFFSET,
    CHAT_CAPTURE_WIDTH,
    CONTACT_LIST_BOTTOM_OFFSET,
    CONTACT_LIST_LEFT_OFFSET,
    CONTACT_LIST_TOP_OFFSET,
    CONTACT_ROW_WIDTH,
    SESSION_NAME_HEIGHT,
    SESSION_NAME_LEFT_OFFSET,
    SESSION_NAME_TOP_OFFSET,
    SESSION_NAME_WIDTH,
    TITLE_OCR_AREA_HEIGHT,
    TITLE_OCR_AREA_LEFT_OFFSET,
    TITLE_OCR_AREA_TOP_OFFSET,
    TITLE_OCR_AREA_WIDTH,
)


@dataclass
class CaptureBox:
    left: int
    top: int
    right: int
    bottom: int

    @property
    def width(self) -> int:
        return self.right - self.left

    @property
    def height(self) -> int:
        return self.bottom - self.top

    def as_tuple(self):
        return (self.left, self.top, self.right, self.bottom)

    def as_dict(self) -> Dict[str, int]:
        return {
            "left": self.left,
            "top": self.top,
            "right": self.right,
            "bottom": self.bottom,
            "width": self.width,
            "height": self.height,
        }


class ScreenshotService:
    def build_box(self, left: int, top: int, width: int, height: int) -> CaptureBox:
        return CaptureBox(
            left=int(left),
            top=int(top),
            right=int(left + width),
            bottom=int(top + height),
        )

    def build_box_from_window(self, window_rect: dict, left_offset: int, top_offset: int, width: int, height: int) -> CaptureBox:
        return self.build_box(
            left=window_rect["left"] + int(left_offset),
            top=window_rect["top"] + int(top_offset),
            width=int(width),
            height=int(height),
        )

    def build_contact_list_box(self, window_rect: dict, left_offset: int, top_offset: int, width: int, bottom_offset: int) -> CaptureBox:
        left = window_rect["left"] + int(left_offset)
        top = window_rect["top"] + int(top_offset)
        right = left + int(width)
        bottom = window_rect["bottom"] - int(bottom_offset)
        return CaptureBox(left=left, top=top, right=right, bottom=bottom)

    def is_valid_box(self, box: CaptureBox) -> bool:
        return box.right > box.left and box.bottom > box.top

    def capture_box(self, left: int, top: int, width: int, height: int):
        box = self.build_box(left, top, width, height)
        if not self.is_valid_box(box):
            raise ValueError(f"invalid capture box: {box.as_dict()}")
        return ImageGrab.grab(bbox=box.as_tuple())

    def capture_from_window(self, window_rect: dict, left_offset: int, top_offset: int, width: int, height: int):
        box = self.build_box_from_window(window_rect, left_offset, top_offset, width, height)
        if not self.is_valid_box(box):
            raise ValueError(f"invalid window capture box: {box.as_dict()}")
        return ImageGrab.grab(bbox=box.as_tuple())

    def capture_contact_list(self, window_rect: dict, left_offset: int, top_offset: int, width: int, bottom_offset: int):
        box = self.build_contact_list_box(window_rect, left_offset, top_offset, width, bottom_offset)
        if not self.is_valid_box(box):
            raise ValueError(f"invalid contact list box: {box.as_dict()}")
        return ImageGrab.grab(bbox=box.as_tuple())

    def get_contact_list_box(self, window_rect: dict) -> CaptureBox:
        return self.build_contact_list_box(
            window_rect,
            left_offset=CONTACT_LIST_LEFT_OFFSET,
            top_offset=CONTACT_LIST_TOP_OFFSET,
            width=CONTACT_ROW_WIDTH,
            bottom_offset=CONTACT_LIST_BOTTOM_OFFSET,
        )

    def capture_contact_list_default(self, window_rect: dict):
        trace_id = new_trace_id("capture")
        box = self.get_contact_list_box(window_rect)
        log_event("INFO", "capture", "capture.contact_list", trace_id, "capture", "ok", "截图会话列表区域", extra=box.as_dict())
        return self.capture_contact_list(
            window_rect,
            left_offset=CONTACT_LIST_LEFT_OFFSET,
            top_offset=CONTACT_LIST_TOP_OFFSET,
            width=CONTACT_ROW_WIDTH,
            bottom_offset=CONTACT_LIST_BOTTOM_OFFSET,
        )

    def get_session_title_box(self, window_rect: dict) -> CaptureBox:
        return self.build_box_from_window(
            window_rect,
            left_offset=TITLE_OCR_AREA_LEFT_OFFSET,
            top_offset=TITLE_OCR_AREA_TOP_OFFSET,
            width=TITLE_OCR_AREA_WIDTH,
            height=TITLE_OCR_AREA_HEIGHT,
        )

    def capture_session_title(self, window_rect: dict):
        trace_id = new_trace_id("capture")
        box = self.get_session_title_box(window_rect)
        log_event("INFO", "capture", "capture.session_title", trace_id, "capture", "ok", "截图会话标题区域", extra=box.as_dict())
        return self.capture_area_from_box(box)

    def get_chat_capture_box(self, window_rect: dict) -> CaptureBox:
        base_height = max(120, CHAT_CAPTURE_HEIGHT)
        max_height = max(base_height, window_rect["height"] - CHAT_CAPTURE_TOP_OFFSET)
        return self.build_box_from_window(
            window_rect,
            left_offset=CHAT_CAPTURE_LEFT_OFFSET,
            top_offset=CHAT_CAPTURE_TOP_OFFSET,
            width=CHAT_CAPTURE_WIDTH,
            height=max_height,
        )

    def capture_chat_area(self, window_rect: dict):
        trace_id = new_trace_id("capture")
        box = self.get_chat_capture_box(window_rect)
        image = self.capture_area_from_box(box)
        chat_bottom = self._detect_chat_bottom_by_binary_merge(image)
        if chat_bottom is not None:
            image = image.crop((0, 0, image.size[0], chat_bottom))
        extra = box.as_dict()
        extra["dynamic_bottom"] = chat_bottom or ""
        extra["final_width"] = image.size[0]
        extra["final_height"] = image.size[1]
        log_event("INFO", "capture", "capture.chat_area", trace_id, "capture", "ok", "截图聊天区域", extra=extra)
        return image

    def crop_session_name(self, row_img):
        return self.crop_from_image(
            row_img,
            left=SESSION_NAME_LEFT_OFFSET,
            top=SESSION_NAME_TOP_OFFSET,
            width=SESSION_NAME_WIDTH,
            height=SESSION_NAME_HEIGHT,
        )

    def capture_area_from_box(self, box: CaptureBox):
        if not self.is_valid_box(box):
            raise ValueError(f"invalid capture box: {box.as_dict()}")
        return ImageGrab.grab(bbox=box.as_tuple())

    def _build_merged_binary_array(self, image_obj):
        arr = np.array(image_obj.convert("RGB"))
        gray = cv2.cvtColor(arr, cv2.COLOR_RGB2GRAY)
        blurred = cv2.GaussianBlur(gray, (5, 5), 0)
        _, binary_inv = cv2.threshold(blurred, 248, 255, cv2.THRESH_BINARY_INV)
        adaptive_inv = cv2.adaptiveThreshold(
            blurred,
            255,
            cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
            cv2.THRESH_BINARY_INV,
            13,
            1,
        )
        merged = cv2.bitwise_or(binary_inv, adaptive_inv)
        kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (5, 1))
        merged = cv2.morphologyEx(merged, cv2.MORPH_CLOSE, kernel, iterations=1)
        merged = cv2.morphologyEx(merged, cv2.MORPH_OPEN, cv2.getStructuringElement(cv2.MORPH_RECT, (2, 2)))
        return merged

    def _detect_chat_bottom_by_binary_merge(self, image_obj) -> int | None:
        if image_obj is None:
            return None
        merged = self._build_merged_binary_array(image_obj)
        img_h, img_w = merged.shape[:2]
        start_y = max(0, int(img_h * 0.55))
        roi = merged[start_y:, :]
        if roi.size == 0:
            return None
        row_density = (roi > 0).mean(axis=1)
        min_run = max(28, int(img_h * 0.045))
        dense_limit = 0.018
        run_start = None
        candidates = []
        for idx, density in enumerate(row_density.tolist() + [1.0]):
            is_blank = density <= dense_limit
            if is_blank and run_start is None:
                run_start = idx
                continue
            if is_blank:
                continue
            if run_start is not None:
                run_end = idx
                if run_end - run_start >= min_run:
                    top = start_y + run_start
                    bottom = start_y + run_end
                    if top >= img_h * 0.58 and bottom <= img_h - 8:
                        candidates.append((top, bottom))
                run_start = None
        if not candidates:
            return self._detect_chat_bottom(image_obj)
        top, _ = candidates[-1]
        bottom = max(120, int(top - 4))
        if bottom >= img_h - 20:
            return None
        return bottom

    def crop_from_image(self, image_obj, left: int, top: int, width: int, height: int):
        if image_obj is None:
            return None
        img_w, img_h = image_obj.size
        crop_left = min(max(0, int(left)), img_w)
        crop_top = min(max(0, int(top)), img_h)
        crop_right = min(img_w, crop_left + max(1, int(width)))
        crop_bottom = min(img_h, crop_top + max(1, int(height)))
        if crop_right <= crop_left or crop_bottom <= crop_top:
            return None
        return image_obj.crop((crop_left, crop_top, crop_right, crop_bottom))

    def _detect_chat_bottom(self, image_obj) -> int | None:
        if image_obj is None:
            return None
        img_rgb = np.array(image_obj.convert("RGB"))
        if img_rgb.size == 0:
            return None
        gray = cv2.cvtColor(img_rgb, cv2.COLOR_RGB2GRAY)
        img_h, img_w = gray.shape[:2]
        start_y = max(0, int(img_h * 0.55))
        focus = gray[start_y:, :]
        if focus.size == 0:
            return None
        row_mean = focus.mean(axis=1)
        row_std = focus.std(axis=1)
        bright_mask = (row_mean >= 242) & (row_std <= 18)
        run = self._find_last_run(bright_mask, min_len=max(18, int(img_h * 0.035)))
        candidate_y = None
        if run is not None:
            run_top, run_bottom = run
            candidate_y = start_y + run_top
        edge_img = cv2.Canny(focus, 40, 120)
        edge_strength = edge_img.mean(axis=1)
        if len(row_mean) >= 2:
            transition = np.abs(np.diff(row_mean, prepend=row_mean[0]))
        else:
            transition = np.zeros_like(row_mean)
        score = edge_strength * 1.8 + transition * 2.4
        score[: max(8, int(len(score) * 0.15))] = 0
        if candidate_y is not None:
            local_limit = max(0, candidate_y - start_y + 4)
            score[local_limit:] = 0
        best_idx = int(np.argmax(score)) if score.size else -1
        best_score = float(score[best_idx]) if best_idx >= 0 else 0.0
        edge_candidate = None
        if best_idx >= 0 and best_score >= 12.0:
            edge_candidate = start_y + best_idx
        final_y = None
        if candidate_y is not None and edge_candidate is not None:
            if abs(candidate_y - edge_candidate) <= 28:
                final_y = min(candidate_y, edge_candidate)
            else:
                final_y = candidate_y
        else:
            final_y = candidate_y if candidate_y is not None else edge_candidate
        if final_y is None:
            return None
        final_y = max(120, min(img_h, int(final_y - 6)))
        if final_y >= img_h - 20:
            return None
        return final_y

    def _find_last_run(self, mask: np.ndarray, min_len: int) -> tuple[int, int] | None:
        run_start = None
        best = None
        for idx, flag in enumerate(mask.tolist() + [False]):
            if flag and run_start is None:
                run_start = idx
                continue
            if flag:
                continue
            if run_start is None:
                continue
            run_len = idx - run_start
            if run_len >= min_len:
                best = (run_start, idx)
            run_start = None
        return best