"""Publication-only validation for same-time-of-day line/scatter comparisons."""
from __future__ import annotations

import re
from collections.abc import Mapping
from datetime import datetime, timedelta, timezone
from typing import Any

from app.domain.domain_errors import require


DISPLAY_TIMEZONE = timezone(timedelta(hours=8))
DAY_SECONDS = 86400


def validate_time_comparison_chart(chart: Mapping[str, Any]) -> None:
    """Validate new publications; persisted historical charts keep their read contract."""
    chart_type = chart["chart_type"]
    series = chart["series"]
    kinds = {item.get("type") or chart_type for item in series}
    if chart_type != "time_comparison":
        require(not {"line", "scatter"} <= kinds, "TIME_COMPARISON_INVALID",
                "曲线与历史散点复合图须使用 chart_type=time_comparison", status=422)
        return

    def check(condition: bool, message: str) -> None:
        require(condition, "TIME_COMPARISON_INVALID", message, status=422)

    kinds = {item.get("type") or "line" for item in series}
    check(kinds == {"line", "scatter"},
          "time_comparison 的 series 必须包含当前 line 和历史 scatter，不能混入 bar")
    labels = chart["x_data"]
    check(all(re.fullmatch(r"(?:[01][0-9]|2[0-3]):[0-5][0-9](?::[0-5][0-9])?", label)
              for label in labels),
          "time_comparison.x_data 只接受 HH:mm 或 HH:mm:ss 时刻；历史日期保留在 sample_times，不能追加到横轴")
    check(len({len(label) for label in labels}) == 1, "x_data 必须使用一致的时刻精度")
    seconds = [sum(int(part) * factor for part, factor in zip(label.split(":"), (3600, 60, 1)))
               for label in labels]
    offsets = [0]
    for index in range(1, len(seconds)):
        step = (seconds[index] - seconds[index - 1]) % DAY_SECONDS
        check(step > 0, f"x_data[{index}] 重复了上一时刻；历史点应复用当前槽位")
        offsets.append(offsets[-1] + step)
    check(offsets[-1] < DAY_SECONDS, "x_data 必须按时间递增且小于一天，不能追加多天历史槽位")

    current_bases: set[datetime] = set()
    historical_bases: list[datetime] = []
    for series_index, item in enumerate(series):
        times = item.get("sample_times")
        path = f"series[{series_index}]"
        check(times is not None and len(times) == len(labels), f"{path}.sample_times 必须提供并与 x_data 等长")
        bases: set[datetime] = set()
        for index, (value, at) in enumerate(zip(item["data"], times, strict=True)):
            check((value is None) == (at is None),
                  f"{path}.sample_times[{index}]：每个有效值必须保留真实带时区时间，缺测值和时间均填 null")
            if at is None:
                continue
            try:
                local = datetime.fromisoformat(at).astimezone(DISPLAY_TIMEZONE)
                base = local - timedelta(seconds=offsets[index])
            except OverflowError:
                check(False, f"{path}.sample_times[{index}] 超出同期对比可表达的日期范围")
            label = labels[index]
            expected = local.strftime("%H:%M:%S" if len(label) == 8 else "%H:%M")
            check(expected == label and local.microsecond == 0 and (len(label) == 8 or local.second == 0),
                  f"{path}.sample_times[{index}] 换算为 UTC+8 后须与 x_data[{index}]={label} 对齐")
            bases.add(base)
        check(len(bases) <= 1, f"{path}.sample_times 必须按同一窗口对齐，不能将不同日期拼入同一组")
        if (item.get("type") or "line") == "line":
            current_bases.update(bases)
        else:
            historical_bases.extend(bases)
    check(len(current_bases) == 1, "当前 line 必须包含真实采样时间，且所有当前曲线使用同一窗口")
    current = next(iter(current_bases))
    for historical in historical_bases:
        delta = (current - historical).total_seconds()
        check(delta > 0 and delta % DAY_SECONDS == 0,
              "历史 scatter 必须来自当前窗口之前的对应日期，不能使用当天或未来采样")