feat: implement template service with builtin and custom templates

- BUILTIN_TEMPLATES: 4 presets (正方形/纵向/横向长方形/左胸小号)
- load_custom_templates(): reads templates.json, skips corrupt entries
  individually so one bad record never blocks the rest
- get_all_templates(): builtin first, then custom
- add_template(): upsert by name, forces type="custom"
- rename_template() / delete_template(): raise ValueError if not found
- _save_custom_templates(): auto-creates config/ dir, logs on failure

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/services/template_service.py

@@ -1,2 +1,191 @@
-def load_templates():
+import json
-    return []
+import logging
+from typing import List, Optional
+
+from core.models import Template
+
+logger = logging.getLogger(__name__)
+
+_TEMPLATES_FILENAME = "templates.json"
+
+# ---------------------------------------------------------------------------
+# 内置模板（代码定义，不可删除/修改）
+# ---------------------------------------------------------------------------
+
+BUILTIN_TEMPLATES: List[Template] = [
+    Template(
+        name="正方形模板",
+        x_ratio=0.25, y_ratio=0.25,
+        width_ratio=0.50, height_ratio=0.50,
+        rotation=0.0, type="builtin",
+    ),
+    Template(
+        name="纵向长方形模板",
+        x_ratio=0.30, y_ratio=0.15,
+        width_ratio=0.40, height_ratio=0.55,
+        rotation=0.0, type="builtin",
+    ),
+    Template(
+        name="横向长方形模板",
+        x_ratio=0.15, y_ratio=0.30,
+        width_ratio=0.70, height_ratio=0.40,
+        rotation=0.0, type="builtin",
+    ),
+    Template(
+        name="左胸小号模板",
+        x_ratio=0.35, y_ratio=0.28,
+        width_ratio=0.12, height_ratio=0.12,
+        rotation=0.0, type="builtin",
+    ),
+]
+
+
+# ---------------------------------------------------------------------------
+# 内部辅助
+# ---------------------------------------------------------------------------
+
+def _templates_file():
+    from services.file_service import get_config_path
+    return get_config_path(_TEMPLATES_FILENAME)
+
+
+def _validate_entry(data) -> Optional[Template]:
+    """Parse one raw dict into a Template; return None and log on any error."""
+    try:
+        name = str(data["name"]).strip()
+        if not name:
+            raise ValueError("name is empty")
+        w = float(data["width_ratio"])
+        h = float(data["height_ratio"])
+        if w <= 0 or h <= 0:
+            raise ValueError("width_ratio and height_ratio must be > 0")
+        return Template(
+            name=name,
+            x_ratio=float(data.get("x_ratio", 0.0)),
+            y_ratio=float(data.get("y_ratio", 0.0)),
+            width_ratio=w,
+            height_ratio=h,
+            rotation=float(data.get("rotation", 0.0)),
+            type="custom",
+        )
+    except (KeyError, ValueError, TypeError) as exc:
+        logger.warning("Skipping invalid template entry (%s): %s", exc, data)
+        return None
+
+
+def _save_custom_templates(templates: List[Template]):
+    """Write custom templates to JSON. Logs error on failure, does not raise."""
+    path = _templates_file()
+    try:
+        path.parent.mkdir(exist_ok=True)
+        payload = {
+            "templates": [
+                {
+                    "name": t.name,
+                    "x_ratio": t.x_ratio,
+                    "y_ratio": t.y_ratio,
+                    "width_ratio": t.width_ratio,
+                    "height_ratio": t.height_ratio,
+                    "rotation": t.rotation,
+                }
+                for t in templates
+            ]
+        }
+        with open(str(path), "w", encoding="utf-8") as f:
+            json.dump(payload, f, ensure_ascii=False, indent=2)
+        logger.info("Saved %d custom template(s) to %s", len(templates), path)
+    except OSError as exc:
+        logger.error("Failed to save templates: %s", exc)
+
+
+# ---------------------------------------------------------------------------
+# 公开 API
+# ---------------------------------------------------------------------------
+
+def get_builtin_templates() -> List[Template]:
+    """Return a copy of the built-in template list."""
+    return list(BUILTIN_TEMPLATES)
+
+
+def load_custom_templates() -> List[Template]:
+    """Load user-defined templates from JSON.
+
+    Returns [] on missing file. Skips corrupt individual entries so a
+    single bad record never blocks the rest.
+    """
+    path = _templates_file()
+    if not path.exists():
+        return []
+
+    try:
+        with open(str(path), encoding="utf-8") as f:
+            data = json.load(f)
+    except (json.JSONDecodeError, OSError) as exc:
+        logger.warning("Cannot read templates.json (%s), ignoring.", exc)
+        return []
+
+    if not isinstance(data, dict) or "templates" not in data:
+        logger.warning("templates.json has unexpected structure, ignoring.")
+        return []
+
+    results = []
+    for entry in data["templates"]:
+        t = _validate_entry(entry)
+        if t is not None:
+            results.append(t)
+
+    logger.info("Loaded %d custom template(s) from %s", len(results), path)
+    return results
+
+
+def get_all_templates() -> List[Template]:
+    """Return builtin templates followed by custom templates."""
+    return get_builtin_templates() + load_custom_templates()
+
+
+def add_template(template: Template):
+    """Add or overwrite a custom template, then persist.
+
+    If a custom template with the same name already exists it is replaced.
+    Built-in templates cannot be added via this function.
+    """
+    template.type = "custom"
+    customs = load_custom_templates()
+    customs = [t for t in customs if t.name != template.name]
+    customs.append(template)
+    _save_custom_templates(customs)
+    logger.info("Template added: %s", template.name)
+
+
+def rename_template(old_name: str, new_name: str):
+    """Rename a custom template and persist.
+
+    Raises ValueError if *old_name* is not found or *new_name* is empty.
+    """
+    new_name = new_name.strip()
+    if not new_name:
+        raise ValueError("New template name cannot be empty")
+    customs = load_custom_templates()
+    found = False
+    for t in customs:
+        if t.name == old_name:
+            t.name = new_name
+            found = True
+            break
+    if not found:
+        raise ValueError("Custom template not found: {}".format(old_name))
+    _save_custom_templates(customs)
+    logger.info("Template renamed: %s -> %s", old_name, new_name)
+
+
+def delete_template(name: str):
+    """Delete a custom template by name and persist.
+
+    Raises ValueError if *name* is not found among custom templates.
+    """
+    customs = load_custom_templates()
+    filtered = [t for t in customs if t.name != name]
+    if len(filtered) == len(customs):
+        raise ValueError("Custom template not found: {}".format(name))
+    _save_custom_templates(filtered)
+    logger.info("Template deleted: %s", name)

tasks.md

@@ -185,19 +185,19 @@
 
 任务：
 
-- [ ] 先读取 `src/services/template_service.py` 现有内容
+- [x] 先读取 `src/services/template_service.py` 现有内容
-- [ ] 完善 `src/services/template_service.py`
+- [x] 完善 `src/services/template_service.py`
-- [ ] 定义内置模板
+- [x] 定义内置模板
-- [ ] 支持读取自定义模板 JSON
+- [x] 支持读取自定义模板 JSON
-- [ ] 支持保存自定义模板 JSON
+- [x] 支持保存自定义模板 JSON
-- [ ] 支持新增、重命名、删除自定义模板
+- [x] 支持新增、重命名、删除自定义模板
-- [ ] 校验模板字段
+- [x] 校验模板字段
 
 验收：
 
-- [ ] 内置模板和自定义模板可区分
+- [x] 内置模板和自定义模板可区分
-- [ ] 单个模板损坏不影响全部模板加载
+- [x] 单个模板损坏不影响全部模板加载
-- [ ] UI 不直接操作模板 JSON 文件
+- [x] UI 不直接操作模板 JSON 文件
 
 ## 5. 图片合成核心