"""图片顺序、模型参考图能力和提示词编号的共享契约；不下载或改写图片。"""

from __future__ import annotations

import re
from PIL import Image

from core.model_capabilities import enabled_chains_for_model
from core.runtime_config import CONFIG


class ImageInputError(ValueError):
    pass


# (pipeline input key, injector capacity)。应用上限仍受 RuntimeConfig 约束。
REFERENCE_CHAIN_SPECS = {
    "qwen_image_edit": ("qwen_image_edit_data", 3),
    "joyai_image": ("joyai_reference_data", 2),
    "boogu_image_edit": ("boogu_edit_data", 10),
    "reference_image": ("reference_image_data", 10),
    "reference_latent": ("reference_latent_data", 10),
    "hidream_o1_reference": ("hidream_o1_reference_data", 10),
    "krea2_identity_edit": ("krea2_identity_edit_data", 2),
    "krea2_style_reference": ("krea2_reference_edit_data", 3),
}
SOURCE_IMAGE_KEYS = {
    "img2img": "img2img_image",
    "inpaint": "inpaint_image",
    "outpaint": "outpaint_image",
    "hires_fix": "hires_image",
}

# 不匹配文件名/标识符；引号和反引号内的文字作为画面文字保留。
# 裸“图”不从构图、地图、草图等常用复合词中截取；保留完整的“参考图 / 图片”别名。
_REFERENCE = re.compile(
    r"(?:(?<![A-Za-z_./\\-])(?:参考图|图片|(?<![构地蓝位视插草绘截贴])图)|(?<![A-Za-z0-9_./\\-])(?:img|image))[ \t]*([0-9０-９]+)"
    r"(?![0-9０-９A-Za-z_./\\-])", re.IGNORECASE,
)
_LITERAL = re.compile(r'("[^"\n]*"|“[^”\n]*”|「[^」\n]*」|`[^`\n]*`)')


def reference_choices(model: str) -> dict[str, dict]:
    enabled = enabled_chains_for_model(model)
    available = [name for name in REFERENCE_CHAIN_SPECS if name in enabled]
    roles = {}
    for role, order in (
        ("auto", available),
        ("identity", ["krea2_identity_edit"]),
        ("style", ["krea2_style_reference"]),
    ):
        chain = next((name for name in order if name in available), None)
        if chain:
            key, limit = REFERENCE_CHAIN_SPECS[chain]
            roles[role] = {
                "chain": chain, "input_key": key,
                "max_images": min(limit, CONFIG.max_multi_images, CONFIG.max_reference_images),
            }
    return roles


def clear_native_references(values: dict) -> None:
    for key, _ in REFERENCE_CHAIN_SPECS.values():
        values[key] = []


def active_reference_groups(values: dict) -> dict[str, list]:
    enabled = enabled_chains_for_model(values.get("model_display_name", ""))
    return {
        chain: [image for image in values.get(key, []) if image is not None]
        for chain, (key, _) in REFERENCE_CHAIN_SPECS.items()
        if chain in enabled and any(image is not None for image in values.get(key, []))
    }


def image_bindings(count: int) -> list[dict]:
    return [
        {"id": f"img{i}", "index": i, "aliases": [f"图{i}", f"img{i}", f"image{i}"],
         "model_reference": f"image {i}"}
        for i in range(1, count + 1)
    ]


def validate_image_budget(images: list) -> None:
    total = 0.0
    for i, image in enumerate(images, 1):
        if not isinstance(image, Image.Image):
            continue  # API 排队前可用未下载的 URL 校验结构。
        megapixels = image.width * image.height / 1_000_000
        if megapixels > CONFIG.max_input_megapixels:
            raise ImageInputError(f"图{i} 为 {megapixels:.1f} MP，超过单图 {CONFIG.max_input_megapixels:g} MP 上限。")
        total += megapixels
    if total > CONFIG.max_reference_megapixels:
        raise ImageInputError(f"图片累计 {total:.1f} MP，超过 {CONFIG.max_reference_megapixels:g} MP 上限；请减少或缩小图片。")


def normalize_image_references(prompt: str, count: int, *, independent=False, ambiguous=False) -> str:
    """仅统一显式编号；不是翻译器，也不承诺所有模型都懂位置指令。"""
    def replace(match):
        if independent:
            raise ImageInputError("多图独立/图片×模型共用提示词，不能跨图引用编号；请写“当前图片”，或改用参考图编辑 / 融合。")
        if ambiguous:
            raise ImageInputError("多个原生参考链同时启用时图片编号不明确；请只保留一个参考链，或使用参考图编辑 / 融合入口。")
        index = int(match.group(1))
        if not 1 <= index <= count:
            raise ImageInputError(f"提示词引用了 {match.group(0)}，但本次只有 {count} 张有效图片；编号从 1 开始。")
        separator = " " if _REFERENCE.match(match.string, match.end()) else ""
        return f"image {index}{separator}"

    parts = _LITERAL.split(prompt or "")
    return "".join(part if index % 2 else _REFERENCE.sub(replace, part) for index, part in enumerate(parts))


def prepare_image_bindings(values: dict, *, independent=False) -> None:
    """在下载模型前处理当前有效输入；调用方持有自己的输入字典。"""
    enabled = enabled_chains_for_model(values.get("model_display_name", ""))
    for chain, (key, _) in REFERENCE_CHAIN_SPECS.items():
        if chain not in enabled:
            values[key] = []
    groups = active_reference_groups(values)
    task = values.get("task_type")
    if task != "txt2img" and groups:
        raise ImageInputError("原生参考图只能用于参考图编辑 / 融合（API 也兼容 txt2img + chain）；普通重绘不要叠加参考链。")
    for chain, images in groups.items():
        limit = REFERENCE_CHAIN_SPECS[chain][1]
        if len(images) > limit:
            raise ImageInputError(f"{chain} 最多支持 {limit} 张参考图，当前为 {len(images)} 张；不会截断图片。")
    count = sum(map(len, groups.values()))
    if count > CONFIG.max_reference_images:
        raise ImageInputError(f"本次参考图超过 {CONFIG.max_reference_images} 张上限。")
    validate_image_budget([image for images in groups.values() for image in images])
    if task in SOURCE_IMAGE_KEYS:
        source = values.get(SOURCE_IMAGE_KEYS[task])
        if task == "inpaint" and source is None:
            source = (values.get("inpaint_image_dict") or {}).get("background")
        count = int(source is not None)
    for key in ("positive_prompt", "negative_prompt"):
        values[key] = normalize_image_references(
            values.get(key, ""), count, independent=independent, ambiguous=len(groups) > 1,
        )
    values["_image_references"] = image_bindings(count) if len(groups) <= 1 else []