import json
import logging
from pathlib import Path
from datetime import datetime
import asyncio

from textual.app import ComposeResult
from textual.screen import Screen, ModalScreen
from textual.containers import Container, Vertical, VerticalScroll, Horizontal, Grid
from textual.widgets import Button, Label, Rule, Tree, Static
from textual import work, on
from rich.text import Text
from rich.style import Style

from src.ui.widgets import RamDisplay
from src.core.backup_reader import BackupReader, ChannelType

logger = logging.getLogger(__name__)

class BackupStatsScreen(Screen[None]):
    """Full-screen view for displaying detailed backup statistics."""

    DEFAULT_CSS = """
    BackupStatsScreen {
        background: $surface;
    }
    
    #bs_scroll_container {
        padding: 1 2;
    }

    #bs_header {
        height: auto;
        layout: horizontal;
        padding-bottom: 1;
        margin-bottom: 1;
        border-bottom: solid $accent;
    }
    
    #bs_header_left {
        width: 1fr;
        height: auto;
        layout: horizontal;
    }
    
    #bs_server_info {
        layout: vertical;
        height: auto;
        margin-left: 1;
    }
    
    .header_title {
        text-style: bold;
    }
    .header_subtitle {
        color: $text-muted;
    }
    
    #bs_header_right {
        width: auto;
        height: auto;
        layout: vertical;
        content-align: right middle;
    }
    
    .top_card_row {
        height: auto;
        layout: horizontal;
        margin-bottom: 1;
    }
    
    .stat_card {
        width: 1fr;
        height: 6;
        layout: vertical;
        border: solid $accent;
        padding: 1;
        margin-right: 1;
        background: $boost;
    }
    .stat_card:focus {
        border: solid $secondary;
    }
    
    .card_title {
        color: $text-muted;
        text-style: bold;
    }
    .card_value {
        text-style: bold;
    }
    
    .entity_row {
        height: auto;
        layout: horizontal;
        margin-bottom: 1;
    }
    
    .wide_card {
        width: 1fr;
        height: auto;
        layout: vertical;
        border: solid $accent;
        padding: 1;
        margin-right: 1;
        background: $boost;
    }
    
    .inner_card_row {
        height: auto;
        layout: horizontal;
        margin-top: 1;
    }
    
    .inner_stat {
        width: 1fr;
        height: 4;
        layout: vertical;
        border: solid $surface;
        background: $surface;
        padding: 0 1;
        content-align: center middle;
        margin-right: 1;
    }
    .inner_stat_value {
        text-style: bold;
        content-align: center middle;
        width: 100%;
    }
    .inner_stat_label {
        color: $text-muted;
        content-align: center middle;
        width: 100%;
    }
    
    #detailed_stats_container {
        height: auto;
        margin-top: 2;
    }
    
    #stats_tree {
        height: auto;
        border: solid $accent;
        background: $boost;
        color: $text;
    }
    
    #bs_actions {
        height: auto;
        margin-top: 1;
        layout: horizontal;
    }
    #bs_actions Button {
        width: 100%;
    }
    """

    def __init__(self, profile_name: str, target_dir: Path, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.profile_name = profile_name
        self.target_dir = target_dir
        self.profile_path = None
        self.backup_path = None

    def compose(self) -> ComposeResult:
        with VerticalScroll(id="bs_scroll_container"):
            # Header
            with Horizontal(id="bs_header"):
                with Horizontal(id="bs_header_left"):
                    yield Label("🚀", id="bs_server_icon") # Fallback icon
                    with Vertical(id="bs_server_info"):
                        yield Label("Loading...", id="bs_name", classes="header_title")
                        yield Label("...", id="bs_id", classes="header_subtitle")
                with Vertical(id="bs_header_right"):
                    yield Label("LAST BACKUP", classes="header_subtitle", id="bs_last_backup_lbl")
                    yield Label("-", id="bs_last_backup", classes="header_title")

            # 4 Top Cards
            with Horizontal(classes="top_card_row"):
                with Vertical(classes="stat_card"):
                    yield Label("# MESSAGES", classes="card_title")
                    yield Label("-", id="bs_val_msgs", classes="card_value")
                with Vertical(classes="stat_card"):
                    yield Label("💭 THREADS", classes="card_title")
                    yield Label("-", id="bs_val_threads", classes="card_value")
                with Vertical(classes="stat_card"):
                    yield Label("📎 ATTACHMENTS", classes="card_title")
                    yield Label("-", id="bs_val_files", classes="card_value")
                with Vertical(classes="stat_card"):
                    yield Label("💾 ATTACHMENTS SIZE", classes="card_title")
                    yield Label("-", id="bs_val_size", classes="card_value")

            # 2 Main Secondary Cards (Combined)
            with Horizontal(classes="entity_row"):
                with Vertical(classes="wide_card"):
                    yield Label("👥 SERVER ENTITIES & COVERAGE", classes="card_title")
                    with Horizontal(classes="inner_card_row"):
                        with Vertical(classes="inner_stat"):
                            yield Label("-", id="bs_val_members", classes="inner_stat_value")
                            yield Label("TOTAL MEMBERS", classes="inner_stat_label")
                        with Vertical(classes="inner_stat"):
                            yield Label("-", id="bs_val_roles", classes="inner_stat_value")
                            yield Label("ROLES DEFINED", classes="inner_stat_label")
                        with Vertical(classes="inner_stat"):
                            yield Label("-", id="bs_val_emojis", classes="inner_stat_value")
                            yield Label("CUSTOM EMOJIS", classes="inner_stat_label")
                        with Vertical(classes="inner_stat"):
                            yield Label("-", id="bs_val_stickers", classes="inner_stat_value")
                            yield Label("CUSTOM STICKERS", classes="inner_stat_label")
                        with Vertical(classes="inner_stat"):
                            yield Label("-", id="bs_val_coverage", classes="inner_stat_value")
                            yield Label("CHANNEL BACKUP", classes="inner_stat_label")

            # Detailed Tree
            with Vertical(id="detailed_stats_container"):
                yield Label("DETAILED CHANNEL & CATEGORY STATISTICS", classes="card_title", id="tree_title")
                yield Tree("Categories", id="stats_tree")

            with Horizontal(id="bs_actions"):
                yield Button("Back", id="btn_back", variant="default")
        yield RamDisplay()

    def on_mount(self) -> None:
        self.stats_tree = self.query_one("#stats_tree", Tree)
        self.stats_tree.root.expand()
        self.stats_tree.show_root = False
        
        # Add a header row to the tree root, purely for visual columns
        # Using depth=4 for header to compensate for root node toggle position delta
        header_text = self._format_tree_row("NAME", "MESSAGES", "THREADS", "FILES", "SIZE", "MANAGE", depth=-1)
        header_text.stylize("bold")
        self.stats_tree.root.set_label(header_text)
        self.stats_tree.show_root = True

        self.load_data()

    def on_button_pressed(self, event: Button.Pressed) -> None:
        if event.button.id == "btn_back":
            self.dismiss()

    @on(Tree.NodeSelected)
    def on_node_selected(self, event: Tree.NodeSelected) -> None:
        """Handle selection of a channel node to open management modal."""
        node_data = event.node.data
        if node_data and node_data.get("is_channel") and node_data.get("is_backed_up"):
            self.app.push_screen(
                ManageBackupModal(
                    node_data["name"],
                    node_data["id"],
                    node_data["stats"],
                    self.target_dir
                ),
                callback=self._on_modal_close
            )

    def _on_modal_close(self, changed: bool) -> None:
        if changed:
            self.load_data()

    def _format_size(self, size_bytes: int) -> str:
        if size_bytes == 0:
            return "0 B"
        if size_bytes < 1024:
            return f"{size_bytes} B"
        if size_bytes < 1024 * 1024:
            return f"{size_bytes / 1024:.1f} KB"
        if size_bytes < 1024 * 1024 * 1024:
            return f"{size_bytes / (1024 * 1024):.2f} MB"
        return f"{size_bytes / (1024 * 1024 * 1024):.2f} GB"

    def _format_tree_row(self, name: str, msgs, threads, files, size, manage="", depth=0) -> Text:
        """Pads and aligns columns for the tree view to simulate a table."""
        # Textual Tree indents child nodes. Standard indent is 4 characters.
        # To maintain vertical alignment of values, we subtract the indentation from the name column width.
        indent_compensation = depth * 2
        
        # Name column: base width is 24.
        name_col_width = max(6, 24 - indent_compensation)
        col_name = str(name)[:name_col_width].ljust(name_col_width)
        
        col_msg = str(msgs).rjust(12)
        col_thd = str(threads).rjust(12)
        col_file = str(files).rjust(12)
        col_size = str(size).rjust(15)
        col_manage = str(manage).rjust(10)
        return Text(f"{col_name}{col_msg}{col_thd}{col_file}{col_size}{col_manage}")

    @work(exclusive=True)
    async def load_data(self) -> None:
        try:
            # Clear old nodes
            while self.stats_tree.root.children:
                self.stats_tree.root.children[0].remove()
                
            # Initialize BackupReader
            reader = BackupReader(self.target_dir)
            await reader.start()
            
            if not reader.guild:
                raise FileNotFoundError(f"No valid backup found in {self.target_dir}")
            
            # 1. Profile / Server Info
            guild = reader.guild
            server_name = guild.name
            server_id = str(guild.id)
            
            # Get last backup info from guild profile
            profile = reader.db.get_guild_profile()
            last_backup_str = "Never"
            ts = profile.get("last_backup")
            if ts:
                try:
                    dt = datetime.fromisoformat(ts)
                    last_backup_str = dt.strftime("%d %b, %Y - %H:%M")
                except Exception:
                    last_backup_str = ts
            
            self.query_one("#bs_name", Label).update(f"{server_name}")
            self.query_one("#bs_id", Label).update(f"{server_id}")
            self.query_one("#bs_last_backup", Label).update(f"{last_backup_str}")

            # 2. Assets / Entities (using properties)
            member_count = len(reader.members)
            emoji_count = len(reader.emojis)
            sticker_count = len(reader.stickers)
            role_count = len(reader.roles)

            self.query_one("#bs_val_members", Label).update(f"{member_count}")
            self.query_one("#bs_val_roles", Label).update(f"{role_count}")
            self.query_one("#bs_val_emojis", Label).update(f"{emoji_count}")
            self.query_one("#bs_val_stickers", Label).update(f"{sticker_count}")

            # 3. Aggregate Stats from DB
            channel_stats = reader.db.get_stats_by_channel()
            
            total_msgs = sum(s["message_count"] for s in channel_stats.values())
            total_threads = sum(s["thread_count"] for s in channel_stats.values())
            total_files = sum(s["attachment_count"] for s in channel_stats.values())
            total_size = sum(s["total_size"] for s in channel_stats.values())
            
            backed_up_channel_ids = set(channel_stats.keys())
            
            # 4. Structure & Per-Channel Stats
            categories = reader.categories
            all_channels = reader.channels
            
            total_channels = len([c for c in all_channels if c.type != ChannelType.category])
            backed_up_channels = len([cid for cid in backed_up_channel_ids if any(c.id == cid for c in all_channels)])
            
            # Helper to map channels to categories
            cat_map = {cat.id: {"cat": cat, "chans": []} for cat in categories}
            cat_map[None] = {"cat": None, "chans": []} # Uncategorized
            
            for chan in all_channels:
                if chan.type == ChannelType.category: continue
                cid = chan.category_id
                if cid not in cat_map: cid = None
                cat_map[cid]["chans"].append(chan)

            # Global update
            self.query_one("#bs_val_msgs", Label).update(f"{total_msgs}")
            self.query_one("#bs_val_threads", Label).update(f"{total_threads}")
            self.query_one("#bs_val_files", Label).update(f"{total_files}")
            self.query_one("#bs_val_size", Label).update(f"{self._format_size(total_size)}")
            self.query_one("#bs_val_coverage", Label).update(f"{backed_up_channels} / {total_channels}")

            # 5. Build Tree - Sort categories to show Uncategorized first, then by name
            sorted_items = sorted(
                cat_map.items(), 
                key=lambda x: (0 if x[0] is None else 1, x[1]["cat"].name if x[0] is not None else "")
            )
            
            for cat_id, info in sorted_items:
                cat = info["cat"]
                chans = info["chans"]
                if not chans: continue
                
                cat_name = cat.name.upper() if cat else "UNCATEGORIZED"
                
                # Aggregate for category
                c_msgs = 0
                c_thds = 0
                c_files = 0
                c_size = 0
                
                chan_nodes_data = []
                for ch in chans:
                    stats = channel_stats.get(ch.id, {"message_count": 0, "thread_count": 0, "attachment_count": 0, "total_size": 0})
                    is_bu = ch.id in backed_up_channel_ids
                    
                    chan_nodes_data.append({
                        "id": ch.id,
                        "name": f"# {ch.name}",
                        "msgs": stats["message_count"] if is_bu else "NA",
                        "threads": stats["thread_count"] if is_bu else "NA",
                        "files": stats["attachment_count"] if is_bu else "NA",
                        "size": stats["total_size"] if is_bu else 0,
                        "is_backed_up": is_bu,
                        "is_channel": True,
                        "stats": stats
                    })
                    
                    c_msgs += stats["message_count"]
                    c_thds += stats["thread_count"]
                    c_files += stats["attachment_count"]
                    c_size += stats["total_size"]
                
                cat_lbl = self._format_tree_row(cat_name, c_msgs, c_thds, c_files, self._format_size(c_size), depth=1)
                cat_lbl.stylize("bold yellow")
                node = self.stats_tree.root.add(cat_lbl, expand=True)
                
                for ch_data in chan_nodes_data:
                    size_str = self._format_size(ch_data['size']) if ch_data['is_backed_up'] else "NA"
                    manage_icon = "🖍️" if ch_data['is_backed_up'] else ""
                    ch_lbl = self._format_tree_row(ch_data['name'], ch_data['msgs'], ch_data['threads'], ch_data['files'], size_str, manage_icon, depth=2)
                    
                    if ch_data['is_backed_up']:
                        ch_lbl.stylize("bold white")
                    else:
                        ch_lbl.stylize("dim white")
                    
                    newNode = node.add_leaf(ch_lbl)
                    newNode.data = ch_data

        except Exception as e:
            import traceback
            logger.exception("Failed to load backup stats")
            trace_str = traceback.format_exc()
            logger.error(f"Full Traceback: {trace_str}")
            self.query_one("#bs_name", Label).update(f"[red]Error loading data[/red]")
            self.query_one("#bs_id", Label).update(f"[red]{e}[/red]")
        finally:
            if 'reader' in locals():
                await reader.close()

class ManageBackupModal(ModalScreen[bool]):
    """Modal for managing channel backup data."""

    DEFAULT_CSS = """
    ManageBackupModal {
        align: center middle;
        background: rgba(0, 0, 0, 0.6);
    }
    
    #mb_container {
        width: 60;
        height: auto;
        max-height: 80%;
        border: thick $accent;
        background: $surface;
        padding: 1 2;
    }
    
    #mb_title {
        text-style: bold;
        margin-bottom: 1;
    }
    
    .mb_info {
        color: $text-muted;
        margin-bottom: 1;
    }
    
    #mb_options {
        margin-top: 1;
        layout: vertical;
        height: auto;
    }
    
    #mb_options Button {
        width: 100%;
        margin-bottom: 1;
    }
    
    #mb_footer {
        margin-top: 1;
        layout: vertical;
        content-align: center middle;
        height: auto;
    }
    
    #mb_confirm_text {
        color: $error;
        text-style: bold italic;
        margin-bottom: 1;
        height: 1;
        content-align: center middle;
        width: 100%;
    }

    #btn_cancel {
        width: 16;
    }
    """

    def __init__(self, channel_name: str, channel_id: int, stats: dict, target_dir: Path, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.channel_name = channel_name
        self.channel_id = channel_id
        self.stats = stats
        self.target_dir = target_dir
        self.primed_button = None # Tracks which button is awaiting second click

    def compose(self) -> ComposeResult:
        with Vertical(id="mb_container"):
            yield Label(f"Manage Backup: {self.channel_name}", id="mb_title")
            
            msgs = self.stats.get("message_count", 0)
            files = self.stats.get("attachment_count", 0)
            yield Label(f"Currently contains {msgs} messages and {files} attachments.", classes="mb_info")
            
            yield Rule()
            
            with Vertical(id="mb_options"):
                yield Button("Delete All Messages", id="btn_delete_msgs", variant="warning")
                yield Button("Delete Messages & Purge Unused Attachments", id="btn_delete_purge", variant="warning")
            
            with Vertical(id="mb_footer"):
                yield Label("", id="mb_confirm_text")
                yield Button("Cancel", id="btn_cancel")

    def on_button_pressed(self, event: Button.Pressed) -> None:
        if event.button.id == "btn_cancel":
            self.dismiss(False)
            return

        btn_id = event.button.id
        if btn_id not in ("btn_delete_msgs", "btn_delete_purge"):
            return

        if self.primed_button == btn_id:
            # Second click, proceed
            purge = (btn_id == "btn_delete_purge")
            self.run_deletion(purge=purge)
        else:
            # First click, prime it
            # Reset other buttons first
            btn_msgs = self.query_one("#btn_delete_msgs", Button)
            btn_purge = self.query_one("#btn_delete_purge", Button)
            btn_msgs.variant = "warning"
            btn_purge.variant = "warning"

            # Prime current click
            event.button.variant = "error"
            self.primed_button = btn_id
            self.query_one("#mb_confirm_text", Label).update("Click again to proceed")

    @work(exclusive=True)
    async def run_deletion(self, purge: bool = False) -> None:
        try:
            from src.core.backup_database import BackupDatabase
            db_path = self.target_dir / "backup.db"
            db = BackupDatabase(db_path)
            
            # 1. Delete messages
            db.delete_channel_messages(self.channel_id)
            
            # 2. Optionally purge
            if purge:
                db.purge_unused_media(self.target_dir)
            
            db.close()
            self.dismiss(True)
        except Exception as e:
            logger.exception("Failed to delete channel data")
            self.app.notify(f"Error: {e}", severity="error")