module/demo_images.py

"""示例场景图片管理 — 优先使用真实图片，缺失时生成合成图片

真实图片位于 test_imgs/complex/ 目录（通过 Git LFS 推送）
文本场景示例由合成生成（模拟合同文档）
"""
import os
from PIL import Image, ImageDraw, ImageFont, ImageFilter


def _get_font(size):
    try:
        return ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", size)
    except Exception:
        try:
            return ImageFont.truetype("DejaVuSans.ttf", size)
        except Exception:
            return ImageFont.load_default()


def _generate_text_scene(path1, path2):
    """生成文本场景示例：模拟合同文档

    两张图内容相同，但图2做了亮度调整和水平偏移，模拟不同角度拍摄
    """
    w, h = 600, 800

    for path, brightness, offset_x in [(path1, 0, 0), (path2, 30, 5)]:
        img = Image.new('RGB', (w, h), (255, 255, 255))
        draw = ImageDraw.Draw(img)

        # 标题区域
        draw.rectangle([50 + offset_x, 40, 550 + offset_x, 80], fill=(30, 30, 30))
        # 正文行
        for i in range(25):
            y = 120 + i * 25
            x_start = 50 + offset_x
            x_end = 550 - (i % 5) * 20 + offset_x
            draw.rectangle([x_start, y, x_end, y + 12], fill=(60, 60, 60))

        # 模拟印章（红色圆形）
        draw.ellipse([400 + offset_x, 650, 500 + offset_x, 750],
                     outline=(180, 30, 30), width=3)
        draw.text((420 + offset_x, 680), "SEAL", fill=(180, 30, 30),
                  font=_get_font(20))

        # 亮度调整
        if brightness > 0:
            import numpy as np
            arr = np.array(img).astype(int) + brightness
            arr = np.clip(arr, 0, 255).astype('uint8')
            img = Image.fromarray(arr)

        img.save(path, 'JPEG', quality=85)


def _scan_real_images(directory):
    """扫描目录中的真实图片文件"""
    if not os.path.isdir(directory):
        return []
    exts = {'.jpg', '.jpeg', '.png', '.bmp', '.webp'}
    imgs = []
    for f in sorted(os.listdir(directory)):
        if os.path.splitext(f)[1].lower() in exts:
            imgs.append(os.path.join(directory, f))
    return imgs


def ensure_demo_images(base_dir):
    """确保示例图片存在，优先使用真实图片

    Args:
        base_dir: 项目根目录
    Returns:
        dict: {'text': [path1, path2], 'complex': [path1, path2]} 或 None
    """
    demo_dir = os.path.join(base_dir, 'test_imgs')
    os.makedirs(demo_dir, exist_ok=True)

    # === 复杂场景：优先使用真实图片 ===
    complex_dir = os.path.join(demo_dir, 'complex')
    real_complex = _scan_real_images(complex_dir)

    if len(real_complex) >= 2:
        complex_imgs = real_complex[:2]
    else:
        # Fallback：生成合成图片
        c1 = os.path.join(demo_dir, 'demo_complex_1.jpg')
        c2 = os.path.join(demo_dir, 'demo_complex_2.jpg')
        if not os.path.exists(c1):
            try:
                _generate_complex_scene(c1, c2)
                print("[示例] 已生成合成复杂场景图片")
            except Exception as e:
                print(f"[示例] 合成复杂场景生成失败: {e}")
                return None
        complex_imgs = [c1, c2]

    # === 文本场景：优先使用真实图片 ===
    text_dir = os.path.join(demo_dir, 'text')
    real_text = _scan_real_images(text_dir)

    if len(real_text) >= 2:
        text_imgs = real_text[:2]
    else:
        # Fallback：生成合成图片
        t1 = os.path.join(demo_dir, 'demo_text_1.jpg')
        t2 = os.path.join(demo_dir, 'demo_text_2.jpg')
        if not os.path.exists(t1):
            try:
                _generate_text_scene(t1, t2)
                print("[示例] 已生成合成文本场景图片")
            except Exception as e:
                print(f"[示例] 合成文本场景生成失败: {e}")
                return None
        text_imgs = [t1, t2]

    return {
        'text': text_imgs,
        'complex': complex_imgs,
    }


def _generate_complex_scene(path1, path2):
    """生成复杂场景示例：模拟实景照片（fallback 用）"""
    w, h = 600, 450

    for path, shift_x, color_shift in [(path1, 0, 0), (path2, 15, 20)]:
        img = Image.new('RGB', (w, h))
        draw = ImageDraw.Draw(img)

        # 天空渐变
        for y in range(h // 2):
            r = int(100 + y * 0.3 + color_shift)
            g = int(150 + y * 0.2)
            b = int(200 + y * 0.15)
            draw.line([(0, y), (w, y)], fill=(min(r, 255), min(g, 255), min(b, 255)))

        # 地面渐变
        for y in range(h // 2, h):
            r = int(80 + (y - h // 2) * 0.3)
            g = int(120 + (y - h // 2) * 0.2)
            b = int(60 + (y - h // 2) * 0.1)
            draw.line([(0, y), (w, y)], fill=(min(r, 255), min(g, 255), min(b, 255)))

        # 太阳
        sun_x = 450 + shift_x
        draw.ellipse([sun_x - 40, 50, sun_x + 40, 130],
                     fill=(255, 220, 100))

        # 山脉
        draw.polygon([(0, 225), (150 + shift_x, 150), (300 + shift_x, 200),
                      (450 + shift_x, 160), (600, 220), (600, 225)],
                     fill=(80, 100, 80))

        # 建筑
        draw.rectangle([100 + shift_x, 250, 200 + shift_x, 400],
                       fill=(120, 100, 90))
        draw.rectangle([250 + shift_x, 280, 350 + shift_x, 400],
                       fill=(100, 110, 100))
        draw.rectangle([400 + shift_x, 260, 480 + shift_x, 400],
                       fill=(90, 80, 100))

        # 轻微模糊模拟不同焦距
        if shift_x > 0:
            img = img.filter(ImageFilter.GaussianBlur(radius=0.8))

        img.save(path, 'JPEG', quality=85)