from __future__ import annotations

from dataclasses import dataclass, field
from typing import Dict, List, Literal, Optional

from app.schemas import EmailMessage, Intent


Difficulty = Literal["easy", "medium", "hard"]
TaskId = Literal["easy_classification", "medium_prioritization", "hard_workflow"]


@dataclass(frozen=True)
class EmailMeta:
    deadline_minutes: Optional[int] = None
    expected_intent: Optional[Intent] = None
    expected_reply_keywords: List[str] = field(default_factory=list)


@dataclass(frozen=True)
class EmailTask:
    task_id: TaskId
    difficulty: Difficulty
    description: str
    max_steps: int
    inbox: List[EmailMessage]
    email_meta: Dict[str, EmailMeta]
    expected_priority_message_id: Optional[str] = None
    expected_send_message_id: Optional[str] = None


def get_all_tasks() -> List[EmailTask]:
    """
    Deterministic hackathon tasks (no IMAP required).
    Full evaluation logic lives in graders + EmailEnv.
    """
    easy_email = EmailMessage(
        message_id="easy-1",
        from_email="customer@example.com",
        subject="Can't log in to my account",
        body="Hi team, I can't log in since yesterday. Password reset link says token invalid. Please help.",
        date="2026-03-30T09:00:00+05:30",
    )

    medium_emails = [
        EmailMessage(
            message_id="med-1",
            from_email="billing@vendor.com",
            subject="Invoice overdue — action required",
            body="Reminder: invoice INV-1842 is overdue. Please confirm payment status within 24 hours.",
            date="2026-03-30T08:40:00+05:30",
        ),
        EmailMessage(
            message_id="med-2",
            from_email="newsletter@updates.com",
            subject="Weekly product updates",
            body="Here's what shipped this week...",
            date="2026-03-30T08:30:00+05:30",
        ),
        EmailMessage(
            message_id="med-3",
            from_email="candidate@example.com",
            subject="Interview availability",
            body="Sharing my availability for next week.",
            date="2026-03-30T08:20:00+05:30",
        ),
    ]

    hard_emails = [
        EmailMessage(
            message_id="hard-1",
            from_email="vip_customer@example.com",
            subject="URGENT: Production outage impacting our team",
            body=(
                "We're seeing 500 errors on checkout since 30 minutes. This is blocking revenue. "
                "Please advise ETA and immediate mitigation."
            ),
            date="2026-03-30T08:55:00+05:30",
        ),
        EmailMessage(
            message_id="hard-2",
            from_email="saleslead@example.com",
            subject="Pricing for 50 seats",
            body="Can you share pricing for 50 seats and if SSO is included?",
            date="2026-03-30T08:10:00+05:30",
        ),
    ]

    return [
        EmailTask(
            task_id="easy_classification",
            difficulty="easy",
            description="Classify a single inbound email into the correct intent.",
            max_steps=4,
            inbox=[easy_email],
            email_meta={"easy-1": EmailMeta(deadline_minutes=120, expected_intent="Support")},
        ),
        EmailTask(
            task_id="medium_prioritization",
            difficulty="medium",
            description="Pick the most urgent email from a small inbox under SLA deadlines.",
            max_steps=5,
            inbox=medium_emails,
            expected_priority_message_id="med-1",
            email_meta={
                "med-1": EmailMeta(deadline_minutes=60, expected_intent="Sales"),
                "med-2": EmailMeta(deadline_minutes=None, expected_intent="General"),
                "med-3": EmailMeta(deadline_minutes=7 * 24 * 60, expected_intent="General"),
            },
        ),
        EmailTask(
            task_id="hard_workflow",
            difficulty="hard",
            description="Run a full workflow: classify, prioritize, draft a reply, and send the correct email.",
            max_steps=10,
            inbox=hard_emails,
            expected_priority_message_id="hard-1",
            expected_send_message_id="hard-1",
            email_meta={
                "hard-1": EmailMeta(
                    deadline_minutes=30,
                    expected_intent="Support",
                    expected_reply_keywords=["mitigation", "eta", "apolog", "impact"],
                ),
                "hard-2": EmailMeta(deadline_minutes=24 * 60, expected_intent="Sales"),
            },
        ),
    ]