"""
views/admin_dashboard_view.py — Admin home screen.

Shows today's completion stats at-a-glance:
  - Headline KPI cards (total users, active today, total sites)
  - Per-user completion table with inline progress bar
  - Auto-refreshes every 60 seconds
"""

import tkinter as tk
from tkinter import ttk
import logging
from datetime import date

from utils.ui_helpers import (
    COLOURS, FONT, FONT_BOLD, FONT_HEADING, FONT_SMALL, FONT_TITLE,
    show_error,
)

logger = logging.getLogger("admin_dashboard_view")

REFRESH_INTERVAL_MS = 60_000   # auto-refresh every 60 seconds


class AdminDashboardView(ttk.Frame):
    def __init__(self, parent, current_user: dict):
        super().__init__(parent)
        self.current_user  = current_user
        self._refresh_job  = None
        self._build_ui()
        self._load()

    def destroy(self):
        """Cancel the auto-refresh job and mousewheel binding when destroyed."""
        if self._refresh_job:
            try:
                self.after_cancel(self._refresh_job)
            except Exception:
                pass
        try:
            self._canvas.unbind_all("<MouseWheel>")
        except Exception:
            pass
        super().destroy()

    # ─── Layout ───────────────────────────────────────────────────────────────

    def _build_ui(self):
        # ── Header ────────────────────────────────────────────────────────────
        hdr = ttk.Frame(self)
        hdr.pack(fill="x", pady=(0, 16))

        ttk.Label(hdr, text="Dashboard",
                  style="Heading.TLabel").pack(side="left")

        self._date_lbl = ttk.Label(
            hdr,
            text=date.today().strftime("%A, %d %B %Y"),
            style="Dim.TLabel"
        )
        self._date_lbl.pack(side="right", padx=(0, 4))

        ttk.Button(hdr, text="↻ Refresh", style="Ghost.TButton",
                   command=self._load).pack(side="right", padx=(0, 8))

        # ── KPI cards row ─────────────────────────────────────────────────────
        self._kpi_frame = tk.Frame(self, bg=COLOURS["bg"])
        self._kpi_frame.pack(fill="x", pady=(0, 20))

        # ── User completion table ─────────────────────────────────────────────
        ttk.Label(self, text="Today's Progress by User",
                  style="Heading.TLabel").pack(anchor="w", pady=(0, 8))

        # Scrollable table frame
        table_outer = ttk.Frame(self)
        table_outer.pack(fill="both", expand=True)

        self._canvas = tk.Canvas(table_outer, bg=COLOURS["bg"],
                                  highlightthickness=0)
        vsb = ttk.Scrollbar(table_outer, orient="vertical",
                             command=self._canvas.yview)
        self._canvas.configure(yscrollcommand=vsb.set)
        vsb.pack(side="right", fill="y")
        self._canvas.pack(side="left", fill="both", expand=True)

        self._table_frame = ttk.Frame(self._canvas)
        self._table_frame.bind(
            "<Configure>",
            lambda e: self._canvas.configure(
                scrollregion=self._canvas.bbox("all"))
        )
        self._canvas_win = self._canvas.create_window(
            (0, 0), window=self._table_frame, anchor="nw"
        )
        self._canvas.bind(
            "<Configure>",
            lambda e: self._canvas.itemconfig(self._canvas_win, width=e.width)
        )
        self._canvas.bind("<Enter>", self._on_canvas_enter)
        self._canvas.bind("<Leave>", self._on_canvas_leave)

    def _on_canvas_enter(self, event):
        self._canvas.bind_all(
            "<MouseWheel>",
            lambda e: self._safe_scroll(e)
        )

    def _on_canvas_leave(self, event):
        try:
            self._canvas.unbind_all("<MouseWheel>")
        except Exception:
            pass

    def _safe_scroll(self, event):
        try:
            self._canvas.yview_scroll(int(-1 * (event.delta / 120)), "units")
        except Exception:
            pass

    # ─── Data ─────────────────────────────────────────────────────────────────

    def _load(self):
        # Cancel any pending auto-refresh before issuing a new one
        if self._refresh_job:
            try:
                self.after_cancel(self._refresh_job)
            except Exception:
                pass

        try:
            from models import get_admin_dashboard_stats
            stats = get_admin_dashboard_stats()
        except Exception as e:
            show_error(f"Failed to load dashboard:\n{e}")
            return

        self._render_kpis(stats)
        self._render_table(stats["user_stats"])

        # Schedule next auto-refresh
        self._refresh_job = self.after(REFRESH_INTERVAL_MS, self._load)
        logger.info("Admin dashboard refreshed.")

    # ─── KPI Cards ────────────────────────────────────────────────────────────

    def _render_kpis(self, stats: dict):
        for w in self._kpi_frame.winfo_children():
            w.destroy()

        total_users  = stats["total_users"]
        active_today = stats["active_today"]
        total_sites  = stats["total_sites"]

        # Compute overall completion %
        user_stats = stats["user_stats"]
        if user_stats:
            avg_pct = sum(
                (r["pct_complete"] or 0) for r in user_stats
            ) / len(user_stats)
        else:
            avg_pct = 0

        cards = [
            ("Total Users",     str(total_users),        COLOURS["accent"]),
            ("Active Today",    str(active_today),       COLOURS["success"]),
            ("Monitored Sites", str(total_sites),        COLOURS["warning"]),
            ("Avg Completion",  f"{avg_pct:.0f}%",       COLOURS["accent"]),
        ]

        self._kpi_frame.columnconfigure(list(range(len(cards))), weight=1)

        for col, (label, value, colour) in enumerate(cards):
            card = tk.Frame(self._kpi_frame, bg=COLOURS["surface"],
                            padx=20, pady=16)
            card.grid(row=0, column=col, padx=(0, 12) if col < len(cards)-1 else 0,
                      sticky="ew")

            tk.Label(card, text=value,
                     font=(FONT_BOLD[0], 26, "bold"),
                     bg=COLOURS["surface"],
                     fg=colour).pack()
            tk.Label(card, text=label,
                     font=FONT_SMALL,
                     bg=COLOURS["surface"],
                     fg=COLOURS["text_dim"]).pack()

    # ─── User Table ───────────────────────────────────────────────────────────

    def _render_table(self, user_stats: list):
        for w in self._table_frame.winfo_children():
            w.destroy()

        # Column headers
        headers = ["User", "Full Name", "Checked", "Total", "Completion"]
        col_weights = [1, 2, 0, 0, 3]
        header_frame = tk.Frame(self._table_frame, bg=COLOURS["surface2"])
        header_frame.pack(fill="x", pady=(0, 2))

        for col, (hdr, wt) in enumerate(zip(headers, col_weights)):
            header_frame.columnconfigure(col, weight=wt, minsize=80)
            tk.Label(header_frame, text=hdr,
                     bg=COLOURS["surface2"], fg=COLOURS["accent"],
                     font=FONT_BOLD, anchor="w",
                     padx=12, pady=8).grid(
                row=0, column=col, sticky="ew")

        if not user_stats:
            tk.Label(self._table_frame,
                     text="No active users with shifts today.",
                     bg=COLOURS["bg"], fg=COLOURS["text_dim"],
                     font=FONT_SMALL).pack(pady=20)
            return

        for i, row in enumerate(user_stats):
            bg = COLOURS["surface"] if i % 2 == 0 else COLOURS["surface2"]
            row_frame = tk.Frame(self._table_frame, bg=bg)
            row_frame.pack(fill="x")

            pct     = float(row["pct_complete"] or 0)
            checked = int(row["checked_count"] or 0)
            total   = int(row["total_sites"]   or 0)

            # Colour: green if 100%, amber if >0%, red if 0%
            if pct >= 100:
                pct_colour = COLOURS["success"]
            elif pct > 0:
                pct_colour = COLOURS["warning"]
            else:
                pct_colour = COLOURS["danger"]

            for col, (wt, content) in enumerate(zip(col_weights, [
                row["username"],
                row["full_name"] or "",
                str(checked),
                str(total),
                None,   # progress bar column
            ])):
                row_frame.columnconfigure(col, weight=wt, minsize=80)

                if content is not None:
                    tk.Label(row_frame, text=content,
                             bg=bg, fg=COLOURS["text"],
                             font=FONT, anchor="w",
                             padx=12, pady=10).grid(
                        row=0, column=col, sticky="ew")
                else:
                    # Progress bar + percentage label
                    bar_cell = tk.Frame(row_frame, bg=bg, padx=12, pady=8)
                    bar_cell.grid(row=0, column=col, sticky="ew")
                    bar_cell.columnconfigure(0, weight=1)

                    # Outer track
                    track = tk.Frame(bar_cell, bg=COLOURS["border"],
                                     height=14)
                    track.pack(fill="x", side="left", expand=True)
                    track.pack_propagate(False)

                    # Fill — drawn after geometry update
                    fill = tk.Frame(track, bg=pct_colour, height=14)
                    fill.place(relx=0, rely=0,
                               relwidth=min(pct / 100, 1.0), relheight=1.0)

                    tk.Label(bar_cell,
                             text=f"{pct:.0f}%",
                             bg=bg, fg=pct_colour,
                             font=FONT_BOLD,
                             width=5, anchor="e").pack(side="left", padx=(6, 0))