"""
FileListWidget — file list based on ttk.Treeview with dark theme styling.
"""

import tkinter as tk
from tkinter import ttk
import customtkinter as ctk

_THEME_APPLIED = False


def _apply_dark_theme():
    global _THEME_APPLIED
    if _THEME_APPLIED:
        return
    _THEME_APPLIED = True

    style = ttk.Style()
    style.theme_use("clam")
    style.configure(
        "Dark.Treeview",
        background="#1e1e1e",
        foreground="#dcdcdc",
        fieldbackground="#1e1e1e",
        borderwidth=0,
        font=("Consolas", 11),
        rowheight=24,
    )
    style.configure(
        "Dark.Treeview.Heading",
        background="#2b2b2b",
        foreground="#9ca3af",
        borderwidth=0,
        font=("Segoe UI", 10, "bold"),
        relief="flat",
    )
    style.map(
        "Dark.Treeview",
        background=[("selected", "#3b82f6")],
        foreground=[("selected", "#ffffff")],
    )
    style.map(
        "Dark.Treeview.Heading",
        background=[("active", "#333333")],
    )
    style.layout("Dark.Treeview", [
        ("Dark.Treeview.treearea", {"sticky": "nswe"}),
    ])


class FileListWidget(ctk.CTkFrame):
    """File list with columns, sorting, multi-selection, drag-and-drop."""

    def __init__(self, master, columns: list[tuple[str, int]],
                 on_navigate=None, on_select=None, on_drop=None):
        super().__init__(master, fg_color="#1e1e1e", corner_radius=6)

        self._on_navigate = on_navigate
        self._on_select = on_select
        self._on_drop = on_drop
        self._items: list[dict] = []
        self._sort_col = None
        self._sort_reverse = False
        self._drag_partner: "FileListWidget | None" = None
        self._drag_start_x = 0
        self._drag_start_y = 0
        self._dragging = False
        self._orig_fg_color = "#1e1e1e"

        _apply_dark_theme()

        col_ids = [c[0] for c in columns]
        self._tree = ttk.Treeview(
            self,
            columns=col_ids,
            show="headings",
            selectmode="extended",
            style="Dark.Treeview",
        )

        for col_name, col_width in columns:
            self._tree.heading(
                col_name,
                text=col_name,
                anchor="w",
                command=lambda c=col_name: self._sort_by_column(c),
            )
            self._tree.column(col_name, width=col_width, minwidth=40, anchor="w")

        scrollbar = ctk.CTkScrollbar(self, command=self._tree.yview)
        self._tree.configure(yscrollcommand=scrollbar.set)

        self._tree.pack(side="left", fill="both", expand=True)
        scrollbar.pack(side="right", fill="y")

        self._tree.bind("<Double-1>", self._on_double_click)
        self._tree.bind("<<TreeviewSelect>>", self._on_tree_select)
        self._tree.bind("<Return>", self._on_enter)

        # Drag-and-drop bindings
        self._tree.bind("<ButtonPress-1>", self._on_drag_start, add="+")
        self._tree.bind("<B1-Motion>", self._on_drag_motion)
        self._tree.bind("<ButtonRelease-1>", self._on_drag_release, add="+")

    def populate(self, items: list[dict]):
        """Fill list with items. Each item: {name, size, date, perm, is_dir}."""
        self._items = items
        self._tree.delete(*self._tree.get_children())

        dirs = [i for i in items if i.get("is_dir")]
        files = [i for i in items if not i.get("is_dir")]
        dirs.sort(key=lambda x: x["name"].lower())
        files.sort(key=lambda x: x["name"].lower())

        for item in dirs + files:
            prefix = "\U0001F4C1 " if item.get("is_dir") else "\U0001F4C4 "
            cols = self._tree.cget("columns")
            values = []
            for c in cols:
                if c == cols[0]:  # Name column
                    values.append(prefix + item.get("name", ""))
                elif c.lower() in ("size", "sizes"):
                    values.append(item.get("size", ""))
                elif c.lower() in ("date", "dates"):
                    values.append(item.get("date", ""))
                elif c.lower() in ("perm", "perms"):
                    values.append(item.get("perm", ""))
                else:
                    values.append(item.get(c.lower(), ""))
            iid = self._tree.insert("", "end", values=values)
            self._tree.item(iid, tags=("dir",) if item.get("is_dir") else ("file",))

    def get_selected(self) -> list[dict]:
        """Return selected items as dicts."""
        result = []
        for iid in self._tree.selection():
            idx = self._tree.index(iid)
            dirs = [i for i in self._items if i.get("is_dir")]
            files = [i for i in self._items if not i.get("is_dir")]
            dirs.sort(key=lambda x: x["name"].lower())
            files.sort(key=lambda x: x["name"].lower())
            ordered = dirs + files
            if 0 <= idx < len(ordered):
                result.append(ordered[idx])
        return result

    def _on_double_click(self, event):
        sel = self.get_selected()
        if sel and sel[0].get("is_dir") and self._on_navigate:
            self._on_navigate(sel[0]["name"])

    def _on_enter(self, event):
        sel = self.get_selected()
        if sel and sel[0].get("is_dir") and self._on_navigate:
            self._on_navigate(sel[0]["name"])

    def _on_tree_select(self, event):
        if self._on_select:
            self._on_select(self.get_selected())

    def _sort_by_column(self, col):
        if self._sort_col == col:
            self._sort_reverse = not self._sort_reverse
        else:
            self._sort_col = col
            self._sort_reverse = False

        cols = self._tree.cget("columns")
        col_map = {cols[0]: "name"}
        for c in cols[1:]:
            col_map[c] = c.lower()

        field = col_map.get(col, "name")

        dirs = [i for i in self._items if i.get("is_dir")]
        files = [i for i in self._items if not i.get("is_dir")]
        dirs.sort(key=lambda x: str(x.get(field, "")).lower(), reverse=self._sort_reverse)
        files.sort(key=lambda x: str(x.get(field, "")).lower(), reverse=self._sort_reverse)

        self._items = dirs + files
        self.populate(self._items)

    # ── Drag-and-drop ──

    def set_drag_partner(self, partner: "FileListWidget"):
        """Link two panels for drag-and-drop."""
        self._drag_partner = partner

    def _on_drag_start(self, event):
        self._drag_start_x = event.x_root
        self._drag_start_y = event.y_root
        self._dragging = False

    def _on_drag_motion(self, event):
        if not self._drag_partner:
            return
        dx = abs(event.x_root - self._drag_start_x)
        dy = abs(event.y_root - self._drag_start_y)
        if not self._dragging and (dx > 10 or dy > 10):
            sel = self.get_selected()
            if sel and any(s["name"] != ".." for s in sel):
                self._dragging = True
                self._tree.configure(cursor="hand2")
                self._drag_partner.configure(fg_color="#1e3a5f")

    def _on_drag_release(self, event):
        if not self._dragging or not self._drag_partner:
            self._dragging = False
            return
        self._dragging = False
        self._tree.configure(cursor="")
        self._drag_partner.configure(fg_color=self._orig_fg_color)

        # Check if mouse is over partner widget
        px = self._drag_partner.winfo_rootx()
        py = self._drag_partner.winfo_rooty()
        pw = self._drag_partner.winfo_width()
        ph = self._drag_partner.winfo_height()
        mx, my = event.x_root, event.y_root

        if px <= mx <= px + pw and py <= my <= py + ph:
            items = [s for s in self.get_selected() if s["name"] != ".."]
            if items and self._drag_partner._on_drop:
                self._drag_partner._on_drop(items, self)