"""采购记录的只读 Qt Model/View 数据源。"""

from __future__ import annotations

from dataclasses import dataclass, field
from typing import Protocol

from PySide6.QtCore import QAbstractTableModel, QModelIndex, Qt

from cmbuyer_client.logging_policy import redact_text
from cmbuyer_client.core.errors import ValidationError
from cmbuyer_client.core.validation import rfc3339_z_nanoseconds


@dataclass(frozen=True)
class PurchaseRecord:
    record_id: str
    title: str
    status: str
    created_at: str
    original_text: str = ""
    result_text: str = ""
    image_description: str = ""
    created_at_nanoseconds: int = field(init=False, repr=False)

    def __post_init__(self) -> None:
        # 记录 provider 只能注入可显示摘要；最终 UI 边界仍统一脱敏，避免
        # consumer bug 把 Bearer/裸 token 放入 model、详情或可见日志。
        for field in ("title", "status", "original_text", "result_text", "image_description"):
            object.__setattr__(self, field, redact_text(getattr(self, field)))
        if not isinstance(self.created_at, str):
            raise ValueError("noncanonical_record_timestamp")
        fraction = self.created_at[20:-1] if len(self.created_at) > 20 and self.created_at.endswith("Z") else ""
        if fraction and fraction.endswith("0"):
            raise ValueError("noncanonical_record_timestamp")
        try:
            timestamp = rfc3339_z_nanoseconds(self.created_at)
        except ValidationError:
            raise ValueError("noncanonical_record_timestamp") from None
        object.__setattr__(self, "created_at_nanoseconds", timestamp)


class PurchaseRecordProvider(Protocol):
    """只返回已准备好的无秘密 View DTO；不得在 GUI 线程查询 SQLite/HTTP。"""

    def snapshot(self) -> list[PurchaseRecord]: ...


class PurchaseRecordModel(QAbstractTableModel):
    RECORD_ID_ROLE = int(Qt.ItemDataRole.UserRole) + 1

    def __init__(self, records: list[PurchaseRecord] | None = None, parent=None) -> None:
        super().__init__(parent)
        self._records: list[PurchaseRecord] = []
        self.set_records(records or [])

    def rowCount(self, parent: QModelIndex = QModelIndex()) -> int:
        return 0 if parent.isValid() else len(self._records)

    def columnCount(self, parent: QModelIndex = QModelIndex()) -> int:
        return 0 if parent.isValid() else 2

    def data(self, index: QModelIndex, role: int = int(Qt.ItemDataRole.DisplayRole)):
        if not index.isValid() or not 0 <= index.row() < len(self._records):
            return None
        record = self._records[index.row()]
        if role == int(Qt.ItemDataRole.DisplayRole):
            return record.title if index.column() == 0 else record.status
        if role == self.RECORD_ID_ROLE:
            return record.record_id
        if role == int(Qt.ItemDataRole.ToolTipRole):
            return f"{record.title}\n{record.created_at}"
        if role == int(Qt.ItemDataRole.TextAlignmentRole) and index.column() == 1:
            return int(Qt.AlignmentFlag.AlignCenter)
        return None

    def headerData(self, section: int, orientation: Qt.Orientation, role: int = int(Qt.ItemDataRole.DisplayRole)):
        if role != int(Qt.ItemDataRole.DisplayRole) or orientation != Qt.Orientation.Horizontal:
            return None
        return ("标题", "状态")[section] if 0 <= section < 2 else None

    def set_records(self, records: list[PurchaseRecord]) -> None:
        self.beginResetModel()
        self._records = sorted(
            records,
            key=lambda item: (item.created_at_nanoseconds, item.record_id),
            reverse=True,
        )
        self.endResetModel()

    def record_at(self, row: int) -> PurchaseRecord | None:
        return self._records[row] if 0 <= row < len(self._records) else None

    def row_for_id(self, record_id: str) -> int:
        return next((row for row, item in enumerate(self._records) if item.record_id == record_id), -1)