from __future__ import annotations

import json
import tkinter as tk
from pathlib import Path
from tkinter import ttk
from typing import Any

from ccma import __version__
from ccma.ui.icons import IconStore

CHANGELOG_PATH = Path(__file__).resolve().parent.parent / "assets" / "CHANGELOG.json"


def load_changelog(path: Path = CHANGELOG_PATH) -> list[dict[str, Any]]:
    try:
        data = json.loads(path.read_text(encoding="utf-8"))
    except (OSError, ValueError, TypeError):
        return []
    if not isinstance(data, list):
        return []
    return [entry for entry in data if isinstance(entry, dict)]


class ChangelogView(ttk.Frame):
    def __init__(self, master: tk.Misc):
        super().__init__(master, padding=14)
        self.icons = IconStore(self)
        self.entries = load_changelog()
        self._build_ui()

    def _build_ui(self) -> None:
        self.columnconfigure(0, weight=1)
        self.rowconfigure(1, weight=1)
        header = ttk.Frame(self)
        header.grid(row=0, column=0, sticky="ew", pady=(0, 14))
        header.columnconfigure(1, weight=1)
        history_icon = self.icons.get("history", 28)
        icon_label = ttk.Label(header, image=history_icon)
        icon_label.image = history_icon
        icon_label.grid(row=0, column=0, rowspan=2, padx=(0, 10))
        ttk.Label(header, text="Änderungsverlauf", style="TabTitle.TLabel").grid(row=0, column=1, sticky="w")
        ttk.Label(
            header,
            text=f"Aktuelle Version {__version__} · {len(self.entries)} Release-Einträge",
            style="Mono.TLabel",
        ).grid(row=1, column=1, sticky="w", pady=(2, 0))

        container = ttk.Frame(self)
        container.grid(row=1, column=0, sticky="nsew")
        container.columnconfigure(0, weight=1)
        container.rowconfigure(0, weight=1)
        background = ttk.Style(self).lookup("TFrame", "background") or "#ffffff"
        self.canvas = tk.Canvas(container, highlightthickness=0, borderwidth=0, background=background)
        scrollbar = ttk.Scrollbar(container, orient="vertical", command=self.canvas.yview)
        self.canvas.configure(yscrollcommand=scrollbar.set)
        self.canvas.grid(row=0, column=0, sticky="nsew")
        scrollbar.grid(row=0, column=1, sticky="ns")
        self.content = ttk.Frame(self.canvas)
        self.content.columnconfigure(0, weight=1)
        self.content_window = self.canvas.create_window((0, 0), anchor="nw", window=self.content)
        self.content.bind("<Configure>", self._update_scroll_region)
        self.canvas.bind("<Configure>", self._resize_content)
        self._render_entries()
        self._bind_mousewheel_tree(self.canvas)
        self._bind_mousewheel_tree(self.content)

    def _render_entries(self) -> None:
        if not self.entries:
            ttk.Label(self.content, text="Kein Changelog verfügbar.", style="Muted.TLabel").grid(
                row=0, column=0, sticky="w", padx=8, pady=8
            )
            return
        for row, entry in enumerate(self.entries):
            version = str(entry.get("version", "unbekannt"))
            card = ttk.LabelFrame(self.content, padding=14)
            card.grid(row=row, column=0, sticky="ew", padx=(0, 8), pady=(0, 12))
            card.columnconfigure(1, weight=1)
            ttk.Label(card, text=f"VERSION {version}", style="TimelineHeader.TLabel").grid(
                row=0, column=0, sticky="w"
            )
            if version == __version__:
                ttk.Label(card, text="CURRENT", style="Mono.TLabel").grid(
                    row=0, column=1, sticky="w", padx=(12, 0)
                )
            ttk.Label(card, text=str(entry.get("date", "")), style="Muted.TLabel").grid(
                row=0, column=2, sticky="e"
            )
            changes = entry.get("changes", [])
            if not isinstance(changes, list):
                continue
            for change_row, change in enumerate(changes, start=1):
                ttk.Label(card, text="•", style="TimelineHeader.TLabel").grid(
                    row=change_row, column=0, sticky="nw", pady=(7, 0)
                )
                ttk.Label(
                    card,
                    text=str(change),
                    justify="left",
                    wraplength=650,
                ).grid(row=change_row, column=1, columnspan=2, sticky="w", padx=(8, 0), pady=(7, 0))

    def _update_scroll_region(self, _event: tk.Event | None = None) -> None:
        self.canvas.configure(scrollregion=self.canvas.bbox("all"))

    def _resize_content(self, event: tk.Event) -> None:
        self.canvas.itemconfigure(self.content_window, width=event.width)

    def _bind_mousewheel_tree(self, widget: tk.Misc) -> None:
        widget.bind("<MouseWheel>", self._on_mousewheel, add="+")
        widget.bind("<Button-4>", self._on_mousewheel, add="+")
        widget.bind("<Button-5>", self._on_mousewheel, add="+")
        for child in widget.winfo_children():
            self._bind_mousewheel_tree(child)

    def _on_mousewheel(self, event: tk.Event) -> None:
        if getattr(event, "num", None) == 4:
            delta = -1
        elif getattr(event, "num", None) == 5:
            delta = 1
        else:
            delta = -1 if getattr(event, "delta", 0) > 0 else 1
        self.canvas.yview_scroll(delta * 3, "units")