"""Slack Bolt app — /oncall command handlers and interactive actions."""

import json
import logging
import os
import re
from datetime import datetime, timedelta
from zoneinfo import ZoneInfo

import boto3
from slack_bolt import App

from src.blocks import (
    build_help_blocks,
    build_roster_blocks,
    build_shift_change_message,
    build_week_schedule,
)
from src.schedule import FALLBACK_EXTENSION, ShiftSchedule

logger = logging.getLogger(__name__)
EASTERN = ZoneInfo("America/New_York")

DAY_NAMES = ["monday", "tuesday", "wednesday", "thursday", "friday", "saturday", "sunday"]


def parse_date(text: str) -> datetime | None:
    """Parse flexible date input: today, tomorrow, day names, m/d, YYYY-MM-DD."""
    now = datetime.now(EASTERN)
    text = text.strip().lower()

    if text == "today":
        return now
    if text == "tomorrow":
        return now + timedelta(days=1)

    if text in DAY_NAMES:
        target = DAY_NAMES.index(text)
        current = now.weekday()
        delta = (target - current) % 7
        if delta == 0:
            delta = 7
        return now + timedelta(days=delta)

    for fmt in ("%Y-%m-%d", "%m/%d/%Y", "%m/%d", "%m-%d"):
        try:
            parsed = datetime.strptime(text, fmt)
            if "%Y" not in fmt:
                parsed = parsed.replace(year=now.year)
                if parsed.replace(tzinfo=EASTERN) < now - timedelta(days=1):
                    parsed = parsed.replace(year=now.year + 1)
            return parsed.replace(tzinfo=EASTERN)
        except ValueError:
            continue

    return None


def invoke_3cx_scheduler(extension: str) -> None:
    """Invoke the 3CX scheduler Lambda to update the ring group immediately."""
    fn_name = os.environ.get("SCHEDULER_FUNCTION_NAME")
    if not fn_name:
        logger.warning("SCHEDULER_FUNCTION_NAME not set — skipping 3CX update")
        return

    client = boto3.client("lambda")
    payload = {"force": True, "override_extension": extension}
    logger.info("Invoking %s with %s", fn_name, payload)
    client.invoke(
        FunctionName=fn_name,
        InvocationType="Event",  # async — don't wait
        Payload=json.dumps(payload),
    )


def is_today(date_str: str) -> bool:
    return date_str == datetime.now(EASTERN).strftime("%Y-%m-%d")


def create_app(bot_token: str, signing_secret: str) -> App:
    app = App(
        token=bot_token,
        signing_secret=signing_secret,
        process_before_response=True,
    )
    schedule = ShiftSchedule()

    # ── /oncall command ─────────────────────────────────────────────────

    @app.command("/oncall")
    def handle_oncall(ack, command, respond, client):
        ack()
        text = (command.get("text") or "").strip()
        user_id = command["user_id"]
        channel_id = command["channel_id"]

        if not text or text == "schedule":
            _show_schedule(respond, schedule)
        elif text == "next":
            _show_next_week(respond, schedule)
        elif text == "help":
            respond(blocks=build_help_blocks())
        elif text == "roster":
            respond(blocks=build_roster_blocks(schedule.get_roster()))
        elif text.startswith("register"):
            _handle_register(respond, schedule, user_id, text)
        elif text.startswith("pick"):
            _handle_pick(respond, schedule, user_id, text, channel_id, client)
        elif text.startswith("drop"):
            _handle_drop(respond, schedule, user_id, text, channel_id, client)
        elif text.startswith("swap"):
            _handle_swap(respond, schedule, user_id, text, channel_id, client)
        else:
            respond(text="Unknown command. Try `/oncall help`")

    # ── Interactive button: pick up open shift ──────────────────────────

    @app.action(re.compile(r"^pickup_"))
    def handle_pickup_button(ack, body, client):
        ack()
        action_id = body["actions"][0]["action_id"]
        date_str = action_id.replace("pickup_", "")
        user_id = body["user"]["id"]
        channel_id = body["channel"]["id"]

        employee = schedule.get_employee_by_slack_id(user_id)
        if not employee:
            client.chat_postEphemeral(
                channel=channel_id,
                user=user_id,
                text="You're not registered. Use `/oncall register <extension>` first.",
            )
            return

        schedule.set_override(date_str, employee["extension"], employee["name"])

        if is_today(date_str):
            invoke_3cx_scheduler(employee["extension"])

        blocks = build_shift_change_message(
            user_id, date_str, "picked_up", employee["extension"], employee["name"]
        )
        client.chat_postMessage(channel=channel_id, blocks=blocks, text=f"Shift picked up for {date_str}")

    # ── Subcommand handlers ─────────────────────────────────────────────

    def _show_schedule(respond, schedule):
        blocks = build_week_schedule(schedule)
        respond(blocks=blocks)

    def _show_next_week(respond, schedule):
        now = datetime.now(EASTERN)
        # Jump 2 weeks ahead from this week's Monday
        this_monday = now - timedelta(days=now.weekday())
        next_start = this_monday + timedelta(days=14)
        blocks = build_week_schedule(schedule, start_date=next_start)
        respond(blocks=blocks)

    def _handle_register(respond, schedule, user_id, text):
        parts = text.split()
        if len(parts) < 2:
            respond(text="Usage: `/oncall register <extension>`  (e.g. `/oncall register 114`)")
            return

        ext = parts[1].strip()
        employee = schedule.register_user(user_id, ext)
        if not employee:
            respond(text=f"Extension {ext} not found in the roster. Check `/oncall roster`.")
            return

        respond(text=f"Linked your account to *{employee['name']}* (Ext {ext}).")

    def _handle_pick(respond, schedule, user_id, text, channel_id, client):
        parts = text.split(maxsplit=1)
        if len(parts) < 2:
            respond(text="Usage: `/oncall pick <date>`  (e.g. `/oncall pick friday`)")
            return

        employee = schedule.get_employee_by_slack_id(user_id)
        if not employee:
            respond(text="You're not registered. Use `/oncall register <extension>` first.")
            return

        date = parse_date(parts[1])
        if not date:
            respond(text=f"Couldn't parse date: `{parts[1]}`. Try: today, tomorrow, friday, 4/5, 2026-04-05")
            return

        date_str = date.strftime("%Y-%m-%d")
        day_name = date.strftime("%A")
        ext, name, source = schedule.resolve_shift(date_str, day_name)

        # Already assigned to someone else (not open)
        if source in ("weekly", "override") and ext != FALLBACK_EXTENSION:
            respond(text=f"That shift is already covered by {name} (Ext {ext}). They'd need to drop it first.")
            return

        schedule.set_override(date_str, employee["extension"], employee["name"])

        if is_today(date_str):
            invoke_3cx_scheduler(employee["extension"])

        blocks = build_shift_change_message(
            user_id, date_str, "picked_up", employee["extension"], employee["name"]
        )
        client.chat_postMessage(channel=channel_id, blocks=blocks, text=f"Shift picked up for {date_str}")
        respond(text=f"You picked up the shift for *{date.strftime('%A, %b %-d')}*.")

    def _handle_drop(respond, schedule, user_id, text, channel_id, client):
        parts = text.split(maxsplit=1)
        if len(parts) < 2:
            respond(text="Usage: `/oncall drop <date>`  (e.g. `/oncall drop friday`)")
            return

        employee = schedule.get_employee_by_slack_id(user_id)
        if not employee:
            respond(text="You're not registered. Use `/oncall register <extension>` first.")
            return

        date = parse_date(parts[1])
        if not date:
            respond(text=f"Couldn't parse date: `{parts[1]}`. Try: today, tomorrow, friday, 4/5, 2026-04-05")
            return

        date_str = date.strftime("%Y-%m-%d")
        day_name = date.strftime("%A")
        ext, name, source = schedule.resolve_shift(date_str, day_name)

        if ext != employee["extension"]:
            respond(text=f"That's not your shift — it belongs to {name} (Ext {ext}).")
            return

        schedule.mark_open(date_str)

        if is_today(date_str):
            invoke_3cx_scheduler(FALLBACK_EXTENSION)

        blocks = build_shift_change_message(user_id, date_str, "dropped", ext, name)
        client.chat_postMessage(channel=channel_id, blocks=blocks, text=f"Shift dropped for {date_str}")
        respond(text=f"You dropped the shift for *{date.strftime('%A, %b %-d')}*. It's now open for pickup.")

    def _handle_swap(respond, schedule, user_id, text, channel_id, client):
        # Expected format: swap <date> @user  OR  swap <date> <extension>
        parts = text.split(maxsplit=2)
        if len(parts) < 3:
            respond(text="Usage: `/oncall swap <date> @person`  (e.g. `/oncall swap friday @sarah`)")
            return

        employee = schedule.get_employee_by_slack_id(user_id)
        if not employee:
            respond(text="You're not registered. Use `/oncall register <extension>` first.")
            return

        date = parse_date(parts[1])
        if not date:
            respond(text=f"Couldn't parse date: `{parts[1]}`.")
            return

        date_str = date.strftime("%Y-%m-%d")
        day_name = date.strftime("%A")
        ext, name, source = schedule.resolve_shift(date_str, day_name)

        if ext != employee["extension"]:
            respond(text=f"That's not your shift — it belongs to {name} (Ext {ext}). You can only swap your own shifts.")
            return

        # Resolve target user — could be <@U12345> or an extension number
        target_text = parts[2].strip()
        slack_id_match = re.match(r"<@(\w+)(?:\|[^>]*)?>", target_text)
        if slack_id_match:
            target_slack_id = slack_id_match.group(1)
            target = schedule.get_employee_by_slack_id(target_slack_id)
            if not target:
                respond(text=f"<@{target_slack_id}> isn't registered. They need to run `/oncall register <extension>`.")
                return
        else:
            target = schedule.get_employee_by_extension(target_text)
            if not target:
                respond(text=f"Extension `{target_text}` not found in the roster.")
                return

        schedule.set_override(date_str, target["extension"], target["name"])

        if is_today(date_str):
            invoke_3cx_scheduler(target["extension"])

        blocks = build_shift_change_message(
            target.get("slack_user_id", user_id),
            date_str,
            "swapped",
            target["extension"],
            target["name"],
        )
        client.chat_postMessage(channel=channel_id, blocks=blocks, text=f"Shift swapped for {date_str}")
        respond(text=f"Swapped *{date.strftime('%A, %b %-d')}* to {target['name']} (Ext {target['extension']}).")

    return app