#!/usr/bin/env python3
"""正点原子逻辑分析仪脉冲频率轨迹查看器。"""

from __future__ import annotations

import bisect
import math
import queue
import threading
import tkinter as tk
from pathlib import Path
from tkinter import filedialog, messagebox, ttk

from logic_waveform import (
    RATE_UNITS,
    FrequencyCurve,
    WaveformChannel,
    WaveformData,
    build_frequency_curves,
    load_waveform,
    parse_marker_times_ms,
)
from parse_logic_csv import CsvParseError


CHANNEL_COLORS = (
    "#2563eb",
    "#dc2626",
    "#16a34a",
    "#ea580c",
    "#7c3aed",
    "#0891b2",
    "#c026d3",
    "#4d7c0f",
)
EDGE_MODES = {
    "自动": "auto",
    "上升沿": "rising",
    "下降沿": "falling",
}


class LogicWaveformApp(tk.Tk):
    """读取逻辑分析仪文件并显示频率随时间的变化。"""

    def __init__(self) -> None:
        super().__init__()
        self.title("正点原子逻辑分析仪脉冲频率轨迹查看器")
        self.geometry("1180x760")
        self.minsize(880, 580)

        self.input_var = tk.StringVar()
        self.sample_rate_var = tk.StringVar(value="20")
        self.sample_rate_unit_var = tk.StringVar(value="MHz")
        self.bin_channel_count_var = tk.StringVar(value="16")
        self.channel_var = tk.StringVar(value="自动")
        self.edge_var = tk.StringVar(value="自动")
        self.marker_var = tk.StringVar(value="100")
        self.status_var = tk.StringVar(value="请选择正点原子导出的 CSV 或 BIN 文件")
        self.file_info_var = tk.StringVar(value="尚未读取频率轨迹")
        self.cursor_var = tk.StringVar(value="光标：-")
        self.marker_info_var = tk.StringVar(value="关键节点：-")

        self.result_queue: queue.Queue[tuple[str, object]] = queue.Queue()
        self.waveform_data: WaveformData | None = None
        self.visible_channels: list[WaveformChannel] = []
        self.frequency_curves: list[FrequencyCurve] = []
        self.marker_times: list[float] = [0.1]
        self.frequency_origin = 0.0
        self.view_start = 0.0
        self.view_end = 1.0
        self.drag_state: tuple[int, float, float] | None = None
        self.redraw_job: str | None = None

        self.load_button: ttk.Button
        self.canvas: tk.Canvas
        self._build_widgets()

    def _build_widgets(self) -> None:
        """创建文件参数区和频率曲线显示区。"""
        self.columnconfigure(0, weight=1)
        self.rowconfigure(3, weight=1)

        header = ttk.Frame(self, padding=(16, 14, 16, 8))
        header.grid(row=0, column=0, sticky="ew")
        header.columnconfigure(0, weight=1)
        ttk.Label(
            header,
            text="脉冲频率轨迹查看器",
            font=("Microsoft YaHei UI", 15, "bold"),
        ).grid(row=0, column=0, sticky="w")
        ttk.Label(header, textvariable=self.status_var).grid(
            row=0, column=1, sticky="e"
        )

        controls = ttk.Frame(self, padding=(16, 0, 16, 8))
        controls.grid(row=1, column=0, sticky="ew")
        controls.columnconfigure(1, weight=1)
        ttk.Label(controls, text="波形文件").grid(row=0, column=0, sticky="w")
        ttk.Entry(controls, textvariable=self.input_var).grid(
            row=0, column=1, sticky="ew", padx=(8, 8)
        )
        ttk.Button(controls, text="选择文件", command=self._choose_input).grid(
            row=0, column=2, padx=(0, 8)
        )
        self.load_button = ttk.Button(
            controls, text="读取并显示", command=self._start_load
        )
        self.load_button.grid(row=0, column=3)

        options = ttk.Frame(self, padding=(16, 0, 16, 10))
        options.grid(row=2, column=0, sticky="ew")
        ttk.Label(options, text="BIN采样率").grid(row=0, column=0, sticky="w")
        ttk.Entry(options, textvariable=self.sample_rate_var, width=9).grid(
            row=0, column=1, padx=(8, 4)
        )
        ttk.Combobox(
            options,
            textvariable=self.sample_rate_unit_var,
            values=("Hz", "kHz", "MHz", "GHz"),
            state="readonly",
            width=6,
        ).grid(row=0, column=2, padx=(0, 18))

        ttk.Label(options, text="BIN通道数").grid(row=0, column=3, sticky="w")
        ttk.Combobox(
            options,
            textvariable=self.bin_channel_count_var,
            values=("8", "16"),
            state="readonly",
            width=5,
        ).grid(row=0, column=4, padx=(8, 18))

        ttk.Label(options, text="显示通道").grid(row=0, column=5, sticky="w")
        ttk.Entry(options, textvariable=self.channel_var, width=14).grid(
            row=0, column=6, padx=(8, 8)
        )

        ttk.Label(options, text="测量边沿").grid(row=1, column=0, sticky="w", pady=(8, 0))
        edge_box = ttk.Combobox(
            options,
            textvariable=self.edge_var,
            values=tuple(EDGE_MODES),
            state="readonly",
            width=8,
        )
        edge_box.grid(row=1, column=1, sticky="w", padx=(8, 18), pady=(8, 0))
        edge_box.bind("<<ComboboxSelected>>", lambda _event: self._apply_plot_settings())

        ttk.Label(options, text="关键时间(ms，逗号分隔，最多10个)").grid(
            row=1, column=3, sticky="w", pady=(8, 0)
        )
        marker_entry = ttk.Entry(options, textvariable=self.marker_var, width=28)
        marker_entry.grid(row=1, column=4, columnspan=2, sticky="w", padx=(8, 8), pady=(8, 0))
        marker_entry.bind("<Return>", lambda _event: self._apply_plot_settings())
        ttk.Button(options, text="更新曲线", command=self._apply_plot_settings).grid(
            row=1, column=6, sticky="w", pady=(8, 0)
        )

        viewer = ttk.Frame(self, padding=(16, 0, 16, 10))
        viewer.grid(row=3, column=0, sticky="nsew")
        viewer.columnconfigure(0, weight=1)
        viewer.rowconfigure(2, weight=1)

        info_bar = ttk.Frame(viewer)
        info_bar.grid(row=0, column=0, sticky="ew", pady=(0, 6))
        info_bar.columnconfigure(0, weight=1)
        ttk.Label(info_bar, textvariable=self.file_info_var).grid(
            row=0, column=0, sticky="w"
        )
        ttk.Label(info_bar, textvariable=self.cursor_var).grid(
            row=0, column=1, sticky="e"
        )

        toolbar = ttk.Frame(viewer)
        toolbar.grid(row=1, column=0, sticky="ew", pady=(0, 6))
        toolbar.columnconfigure(3, weight=1)
        ttk.Button(toolbar, text="放大", command=lambda: self._zoom_view(0.6)).grid(
            row=0, column=0
        )
        ttk.Button(toolbar, text="缩小", command=lambda: self._zoom_view(1.6)).grid(
            row=0, column=1, padx=(6, 0)
        )
        ttk.Button(toolbar, text="适应窗口", command=self._fit_view).grid(
            row=0, column=2, padx=(6, 0)
        )
        ttk.Label(
            toolbar,
            textvariable=self.marker_info_var,
            wraplength=800,
        ).grid(
            row=1, column=0, columnspan=4, sticky="w", pady=(6, 0)
        )

        self.canvas = tk.Canvas(
            viewer,
            background="#ffffff",
            highlightthickness=1,
            highlightbackground="#aeb4bc",
            cursor="crosshair",
        )
        self.canvas.grid(row=2, column=0, sticky="nsew")
        self.canvas.bind("<Configure>", lambda _event: self._schedule_redraw())
        self.canvas.bind("<MouseWheel>", self._on_mouse_wheel)
        self.canvas.bind("<ButtonPress-1>", self._start_drag)
        self.canvas.bind("<B1-Motion>", self._drag_view)
        self.canvas.bind("<ButtonRelease-1>", self._end_drag)
        self.canvas.bind("<Motion>", self._show_cursor)
        self.canvas.bind("<Leave>", self._hide_cursor)

    def _choose_input(self) -> None:
        """选择 CSV 或 BIN 文件并立即读取。"""
        path = filedialog.askopenfilename(
            title="选择正点原子逻辑分析仪波形文件",
            filetypes=(
                ("逻辑分析仪文件", "*.csv *.bin"),
                ("CSV 文件", "*.csv"),
                ("BIN 文件", "*.bin"),
                ("所有文件", "*.*"),
            ),
        )
        if not path:
            return
        self.input_var.set(path)
        self._start_load()

    def _get_bin_sample_rate(self) -> float:
        """读取界面中的 BIN 采样率。"""
        try:
            value = float(self.sample_rate_var.get().strip())
        except ValueError as exc:
            raise CsvParseError("BIN 采样率必须是数字") from exc
        if value <= 0:
            raise CsvParseError("BIN 采样率必须大于 0")
        return value * RATE_UNITS[self.sample_rate_unit_var.get().lower()]

    def _start_load(self) -> None:
        """校验参数并在后台读取波形文件。"""
        input_name = self.input_var.get().strip()
        if not input_name:
            messagebox.showwarning("未选择文件", "请先选择 CSV 或 BIN 文件。")
            return
        path = Path(input_name)
        if not path.is_file():
            messagebox.showerror("文件不存在", f"找不到文件：\n{path}")
            return
        try:
            sample_rate = self._get_bin_sample_rate()
            channel_count = int(self.bin_channel_count_var.get())
            parse_marker_times_ms(self.marker_var.get())
        except (ValueError, CsvParseError) as exc:
            messagebox.showerror("参数错误", str(exc))
            return

        self.load_button.configure(state="disabled")
        self.status_var.set("正在读取并计算频率……")
        self.file_info_var.set(f"正在读取：{path.name}")
        worker = threading.Thread(
            target=self._load_worker,
            args=(path, sample_rate, channel_count, self.channel_var.get()),
            daemon=True,
        )
        worker.start()
        self.after(100, self._check_load_result)

    def _load_worker(
        self,
        path: Path,
        sample_rate: float,
        channel_count: int,
        channel_text: str,
    ) -> None:
        """在线程中解析较大的 BIN 文件。"""
        try:
            result = load_waveform(path, sample_rate, channel_count, channel_text)
            self.result_queue.put(("ok", result))
        except (OSError, CsvParseError) as exc:
            self.result_queue.put(("error", str(exc)))

    def _check_load_result(self) -> None:
        """接收后台解析结果并生成频率曲线。"""
        try:
            result_type, result = self.result_queue.get_nowait()
        except queue.Empty:
            self.after(100, self._check_load_result)
            return

        self.load_button.configure(state="normal")
        if result_type == "error":
            self.status_var.set("读取失败")
            self.file_info_var.set("波形文件读取失败")
            messagebox.showerror("读取失败", str(result))
            return

        data, channels = result  # type: ignore[misc]
        self.waveform_data = data
        self.visible_channels = channels
        try:
            self._rebuild_frequency_curves()
        except CsvParseError as exc:
            self.status_var.set("频率计算失败")
            messagebox.showerror("频率计算失败", str(exc))
            return
        self.file_info_var.set(self._build_file_info(data))
        self.status_var.set(f"已生成 {len(self.frequency_curves)} 条频率曲线")

    def _apply_plot_settings(self) -> None:
        """应用测量边沿和关键时间设置。"""
        if self.waveform_data is None:
            return
        try:
            self._rebuild_frequency_curves()
        except CsvParseError as exc:
            messagebox.showerror("曲线设置错误", str(exc))

    def _rebuild_frequency_curves(self) -> None:
        """按当前边沿设置重新计算频率轨迹。"""
        edge_mode = EDGE_MODES[self.edge_var.get()]
        self.marker_times = parse_marker_times_ms(self.marker_var.get())
        self.frequency_curves = build_frequency_curves(
            self.visible_channels, edge_mode
        )
        self.frequency_origin = min(curve.start_time for curve in self.frequency_curves)
        self.view_start = self.frequency_origin
        self.view_end = max(curve.end_time for curve in self.frequency_curves)
        if self.view_end <= self.view_start:
            self.view_end = self.view_start + 1e-6
        self._update_marker_summary()
        self.cursor_var.set("光标：-")
        self._schedule_redraw()

    @staticmethod
    def _build_file_info(data: WaveformData) -> str:
        """生成文件采样信息。"""
        parts = [data.source_type]
        if data.sample_rate:
            parts.append(f"采样率 {format_frequency(data.sample_rate)}")
        if data.sample_count is not None:
            parts.append(f"采样点 {data.sample_count:,}")
        if data.source_type == "CSV":
            parts.append(f"记录行 {data.record_count:,}")
        return "  |  ".join(parts)

    def _update_marker_summary(self) -> None:
        """在工具栏显示所有关键节点的测量结果。"""
        if not self.marker_times or not self.frequency_curves:
            self.marker_info_var.set("关键节点：-")
            return
        summaries = []
        for marker in self.marker_times:
            target_time = self.frequency_origin + marker
            values = []
            for curve in self.frequency_curves:
                if target_time > curve.end_time:
                    values.append(f"{curve.channel_name} 超出范围")
                    continue
                measured_time, frequency = curve.frequency_at(target_time)
                measured_ms = (measured_time - self.frequency_origin) * 1_000.0
                values.append(
                    f"{curve.channel_name} {format_frequency(frequency)}"
                    f"@{measured_ms:.3f}ms"
                )
            summaries.append(f"{marker * 1000:g}ms：" + "  |  ".join(values))
        self.marker_info_var.set("    ".join(summaries))

    def _plot_bounds(self) -> tuple[float, float, float, float]:
        """返回频率曲线绘图区边界。"""
        width = max(1, self.canvas.winfo_width())
        height = max(1, self.canvas.winfo_height())
        return 92.0, 35.0, max(93.0, width - 24.0), max(36.0, height - 58.0)

    def _schedule_redraw(self) -> None:
        """合并连续的重绘请求。"""
        if self.redraw_job is None:
            self.redraw_job = self.after_idle(self._draw_frequency_chart)

    def _draw_frequency_chart(self) -> None:
        """绘制频率随时间变化的曲线。"""
        self.redraw_job = None
        self.canvas.delete("all")
        if not self.frequency_curves:
            self.canvas.create_text(
                self.canvas.winfo_width() / 2,
                self.canvas.winfo_height() / 2,
                text="请选择包含脉冲的 CSV 或 BIN 文件",
                fill="#6b7280",
                font=("Microsoft YaHei UI", 12),
            )
            return

        left, top, right, bottom = self._plot_bounds()
        plot_width = right - left
        plot_height = bottom - top
        time_span = max(self.view_end - self.view_start, 1e-15)
        maximum_frequency = nice_frequency_max(self._visible_max_frequency())

        # 绘制横向频率网格和纵轴刻度。
        for tick in range(9):
            ratio = tick / 8.0
            y = bottom - ratio * plot_height
            frequency = ratio * maximum_frequency
            self.canvas.create_line(left, y, right, y, fill="#e2e5e9", width=1)
            self.canvas.create_text(
                left - 9,
                y,
                anchor="e",
                text=format_hz_tick(frequency),
                fill="#4b5563",
                font=("Consolas", 9),
            )

        # 绘制时间网格，横轴从第一个有效脉冲边沿开始计时。
        time_scale, time_unit = choose_time_unit(time_span)
        for tick in range(11):
            ratio = tick / 10.0
            x = left + ratio * plot_width
            time_value = self.view_start + ratio * time_span
            relative_time = (time_value - self.frequency_origin) * time_scale
            self.canvas.create_line(x, top, x, bottom, fill="#edf0f3", width=1)
            self.canvas.create_text(
                x,
                bottom + 18,
                text=format_tick(relative_time),
                fill="#4b5563",
                font=("Consolas", 9),
            )

        self.canvas.create_text(
            20,
            (top + bottom) / 2,
            text="脉冲频率 (Hz)",
            angle=90,
            fill="#111827",
            font=("Microsoft YaHei UI", 10),
        )
        self.canvas.create_text(
            (left + right) / 2,
            bottom + 42,
            text=f"脉冲开始后的时间 ({time_unit})",
            fill="#111827",
            font=("Microsoft YaHei UI", 10),
        )

        for curve_number, curve in enumerate(self.frequency_curves):
            color = CHANNEL_COLORS[curve.channel_index % len(CHANNEL_COLORS)]
            self._draw_curve(
                curve, left, right, top, bottom, maximum_frequency, color
            )
            self.canvas.create_line(
                left + curve_number * 190,
                16,
                left + 20 + curve_number * 190,
                16,
                fill=color,
                width=3,
            )
            self.canvas.create_text(
                left + 26 + curve_number * 190,
                16,
                anchor="w",
                text=f"{curve.channel_name}（{curve.edge_name}）",
                fill="#1f2937",
                font=("Microsoft YaHei UI", 9, "bold"),
            )

        self._draw_markers(left, right, top, bottom, maximum_frequency)
        self.canvas.create_line(left, top, left, bottom, fill="#4b5563", width=1)
        self.canvas.create_line(left, bottom, right, bottom, fill="#4b5563", width=1)

    def _visible_max_frequency(self) -> float:
        """读取当前时间窗口中的最大频率。"""
        maximum = 0.0
        for curve in self.frequency_curves:
            start = max(0, bisect.bisect_left(curve.times, self.view_start) - 1)
            end = min(len(curve.times), bisect.bisect_right(curve.times, self.view_end) + 1)
            if start < end:
                maximum = max(maximum, max(curve.frequencies[start:end]))
        return max(maximum, 1.0)

    def _draw_curve(
        self,
        curve: FrequencyCurve,
        left: float,
        right: float,
        top: float,
        bottom: float,
        maximum_frequency: float,
        color: str,
    ) -> None:
        """绘制一条频率轨迹。"""
        start = max(0, bisect.bisect_left(curve.times, self.view_start) - 1)
        end = min(len(curve.times), bisect.bisect_right(curve.times, self.view_end) + 1)
        if end - start < 2:
            return
        time_span = self.view_end - self.view_start
        plot_width = right - left
        plot_height = bottom - top
        indexes = list(range(start, end))
        maximum_points = max(100, int(plot_width * 3))
        if len(indexes) > maximum_points:
            indexes = decimate_curve_indexes(
                curve.frequencies, start, end, maximum_points
            )

        coordinates: list[float] = []
        for index in indexes:
            x = left + (curve.times[index] - self.view_start) / time_span * plot_width
            y = bottom - curve.frequencies[index] / maximum_frequency * plot_height
            coordinates.extend((x, y))
        self.canvas.create_line(*coordinates, fill=color, width=2, smooth=False)

    def _draw_markers(
        self,
        left: float,
        right: float,
        top: float,
        bottom: float,
        maximum_frequency: float,
    ) -> None:
        """标出用户设置的关键时间和对应频率。"""
        time_span = self.view_end - self.view_start
        plot_height = bottom - top
        for marker in self.marker_times:
            target_time = self.frequency_origin + marker
            if not self.view_start <= target_time <= self.view_end:
                continue
            x = left + (target_time - self.view_start) / time_span * (right - left)
            self.canvas.create_line(
                x, top, x, bottom, fill="#d97706", width=1, dash=(5, 4)
            )
            self.canvas.create_text(
                x + 5,
                top + 4,
                anchor="nw",
                text=f"{marker * 1000:g} ms",
                fill="#92400e",
                font=("Microsoft YaHei UI", 9, "bold"),
            )
            for curve_number, curve in enumerate(self.frequency_curves):
                if target_time > curve.end_time:
                    continue
                measured_time, frequency = curve.frequency_at(target_time)
                point_x = left + (measured_time - self.view_start) / time_span * (right - left)
                point_y = bottom - frequency / maximum_frequency * plot_height
                color = CHANNEL_COLORS[curve.channel_index % len(CHANNEL_COLORS)]
                self.canvas.create_oval(
                    point_x - 4,
                    point_y - 4,
                    point_x + 4,
                    point_y + 4,
                    fill="#ffffff",
                    outline=color,
                    width=2,
                )
                self.canvas.create_text(
                    point_x + 7,
                    point_y - 7 - curve_number * 17,
                    anchor="sw",
                    text=format_frequency(frequency),
                    fill=color,
                    font=("Microsoft YaHei UI", 9, "bold"),
                )

    def _full_time_range(self) -> tuple[float, float]:
        """返回所有频率曲线的完整时间范围。"""
        start = self.frequency_origin
        end = max(curve.end_time for curve in self.frequency_curves)
        return start, max(end, start + 1e-15)

    def _fit_view(self) -> None:
        """恢复频率曲线的完整时间范围。"""
        if not self.frequency_curves:
            return
        self.view_start, self.view_end = self._full_time_range()
        self._schedule_redraw()

    def _zoom_view(self, factor: float, anchor_x: float | None = None) -> None:
        """以鼠标位置或窗口中心为基准缩放时间轴。"""
        if not self.frequency_curves:
            return
        left, _top, right, _bottom = self._plot_bounds()
        ratio = 0.5
        if anchor_x is not None and right > left:
            ratio = min(1.0, max(0.0, (anchor_x - left) / (right - left)))
        old_span = self.view_end - self.view_start
        full_start, full_end = self._full_time_range()
        full_span = full_end - full_start
        minimum_span = max(full_span / 1_000_000_000.0, 1e-12)
        new_span = min(full_span, max(minimum_span, old_span * factor))
        anchor_time = self.view_start + old_span * ratio
        new_start = anchor_time - new_span * ratio
        self._set_view_range(new_start, new_start + new_span)

    def _set_view_range(self, start: float, end: float) -> None:
        """限制时间窗口不能移出频率曲线范围。"""
        if not self.frequency_curves:
            return
        full_start, full_end = self._full_time_range()
        span = min(end - start, full_end - full_start)
        if start < full_start:
            start = full_start
        if start + span > full_end:
            start = full_end - span
        self.view_start = start
        self.view_end = start + span
        self._schedule_redraw()

    def _on_mouse_wheel(self, event: tk.Event) -> None:
        """使用鼠标滚轮缩放时间轴。"""
        factor = 0.75 if event.delta > 0 else 1.35
        self._zoom_view(factor, float(event.x))

    def _start_drag(self, event: tk.Event) -> None:
        """记录拖动开始位置。"""
        if self.frequency_curves:
            self.drag_state = (event.x, self.view_start, self.view_end)

    def _drag_view(self, event: tk.Event) -> None:
        """按鼠标水平位移平移时间轴。"""
        if self.drag_state is None:
            return
        start_x, original_start, original_end = self.drag_state
        left, _top, right, _bottom = self._plot_bounds()
        if right <= left:
            return
        time_shift = -(event.x - start_x) / (right - left) * (
            original_end - original_start
        )
        self._set_view_range(original_start + time_shift, original_end + time_shift)

    def _end_drag(self, _event: tk.Event) -> None:
        """结束鼠标拖动。"""
        self.drag_state = None

    def _show_cursor(self, event: tk.Event) -> None:
        """显示鼠标时间位置和各通道的实测频率。"""
        if not self.frequency_curves:
            return
        left, top, right, bottom = self._plot_bounds()
        if not left <= event.x <= right or not top <= event.y <= bottom:
            self._hide_cursor(event)
            return
        ratio = (event.x - left) / (right - left)
        time_value = self.view_start + ratio * (self.view_end - self.view_start)
        relative_time = time_value - self.frequency_origin
        values = []
        for curve in self.frequency_curves:
            _measured_time, frequency = curve.frequency_at(time_value)
            values.append(f"{curve.channel_name} {format_frequency(frequency)}")
        self.canvas.delete("cursor")
        self.canvas.create_line(
            event.x,
            top,
            event.x,
            bottom,
            fill="#374151",
            dash=(3, 3),
            tags="cursor",
        )
        self.cursor_var.set(
            f"光标 {format_duration(relative_time)}：" + "  |  ".join(values)
        )

    def _hide_cursor(self, _event: tk.Event | None = None) -> None:
        """清除鼠标光标线。"""
        self.canvas.delete("cursor")
        self.cursor_var.set("光标：-")


def nice_frequency_max(value: float) -> float:
    """把纵轴最大频率向上取为 1、2、5、10 的整倍数。"""
    if value <= 0:
        return 1.0
    exponent = 10 ** math.floor(math.log10(value))
    fraction = value / exponent
    for candidate in (1.0, 2.0, 5.0, 10.0):
        if fraction <= candidate:
            return candidate * exponent
    return 10.0 * exponent


def decimate_curve_indexes(
    frequencies: list[float], start: int, end: int, maximum_points: int
) -> list[int]:
    """抽取曲线点，同时保留每个时间桶内的最高值和最低值。"""
    point_count = end - start
    if point_count <= maximum_points:
        return list(range(start, end))
    bucket_count = max(1, maximum_points // 2)
    indexes = [start]
    for bucket in range(bucket_count):
        bucket_start = start + int(bucket * point_count / bucket_count)
        bucket_end = start + int((bucket + 1) * point_count / bucket_count)
        bucket_end = min(end, max(bucket_start + 1, bucket_end))
        minimum_index = min(
            range(bucket_start, bucket_end), key=frequencies.__getitem__
        )
        maximum_index = max(
            range(bucket_start, bucket_end), key=frequencies.__getitem__
        )
        indexes.extend(sorted((minimum_index, maximum_index)))
    indexes.append(end - 1)
    return sorted(set(indexes))


def choose_time_unit(span: float) -> tuple[float, str]:
    """根据当前时间范围选择合适的横轴单位。"""
    if span >= 1.0:
        return 1.0, "s"
    if span >= 0.001:
        return 1_000.0, "ms"
    if span >= 0.000001:
        return 1_000_000.0, "us"
    return 1_000_000_000.0, "ns"


def format_tick(value: float) -> str:
    """格式化时间轴刻度。"""
    absolute = abs(value)
    if absolute >= 1000:
        return f"{value:.0f}"
    if absolute >= 10:
        return f"{value:.2f}"
    return f"{value:.3f}"


def format_hz_tick(frequency: float) -> str:
    """以 Hz 为单位格式化纵轴刻度。"""
    if frequency >= 100:
        return f"{frequency:.0f}"
    if frequency >= 10:
        return f"{frequency:.1f}"
    return f"{frequency:.2f}"


def format_frequency(frequency: float) -> str:
    """使用 Hz、kHz、MHz 或 GHz 显示测量结果。"""
    if frequency >= 1_000_000_000:
        return f"{frequency / 1_000_000_000:.4g} GHz"
    if frequency >= 1_000_000:
        return f"{frequency / 1_000_000:.4g} MHz"
    if frequency >= 1_000:
        return f"{frequency / 1_000:.4g} kHz"
    return f"{frequency:.4g} Hz"


def format_duration(duration: float) -> str:
    """使用合适单位显示时间长度。"""
    if duration >= 1.0:
        return f"{duration:.6g} s"
    if duration >= 0.001:
        return f"{duration * 1_000:.6g} ms"
    if duration >= 0.000001:
        return f"{duration * 1_000_000:.6g} us"
    return f"{duration * 1_000_000_000:.6g} ns"


def main() -> None:
    """启动脉冲频率轨迹查看器。"""
    app = LogicWaveformApp()
    app.mainloop()


if __name__ == "__main__":
    main()