"""Bulk CSV import for organization members.

TODO: Move large imports to an async batch job with webhook completion callbacks.
"""

from __future__ import annotations

import re

from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models import Account
from app.schemas import (
    OrgMemberCreate,
    OrgMemberImportRequest,
    OrgMemberImportResponse,
    OrgMemberImportRowResult,
    OrgMemberRead,
)
from app.services.org_members import create_org_member

MAX_IMPORT_ROWS = 300
EMAIL_LOCAL_PATTERN = re.compile(
    r"^[A-Za-z0-9](?:[A-Za-z0-9._-]{0,62}[A-Za-z0-9])?$"
)


def _password_error(value: str) -> str | None:
    if len(value) < 8:
        return "Password must be at least 8 characters."
    if not (
        re.search(r"[a-z]", value)
        and re.search(r"[A-Z]", value)
        and re.search(r"\d", value)
    ):
        return "Password must include uppercase, lowercase, and a number."
    return None


def _normalize_work_email(raw: str, company_domain: str) -> str:
    value = raw.strip().lower()
    if "@" in value:
        return value
    return f"{value}@{company_domain}"


async def import_org_members(
    session: AsyncSession,
    *,
    manager: Account,
    payload: OrgMemberImportRequest,
) -> OrgMemberImportResponse:
    company_domain = manager.company_domain
    if company_domain is None:
        raise ValueError("Company domain is required.")

    rows = payload.rows
    if not rows:
        raise ValueError("Add at least one person to import.")
    if len(rows) > MAX_IMPORT_ROWS:
        raise ValueError(f"You can import up to {MAX_IMPORT_ROWS} people at a time.")

    errors: list[OrgMemberImportRowResult] = []
    normalized_rows: list[tuple[int, OrgMemberCreate]] = []
    seen_emails: set[str] = set()
    seen_invites: set[str] = set()

    for index, row in enumerate(rows, start=1):
        row_errors: list[str] = []
        first_name = row.first_name.strip()
        last_name = row.last_name.strip()
        if not first_name:
            row_errors.append("First name is required.")
        if not last_name:
            row_errors.append("Last name is required.")

        work_email = _normalize_work_email(row.work_email, company_domain)
        local_part = work_email.split("@", 1)[0]
        if not work_email.endswith(f"@{company_domain}"):
            row_errors.append(f"Work email must use @{company_domain}.")
        elif not EMAIL_LOCAL_PATTERN.match(local_part):
            row_errors.append("Work email format is invalid.")

        if work_email in seen_emails:
            row_errors.append("Duplicate work email in this file.")
        seen_emails.add(work_email)

        password = row.password.strip()
        password_issue = _password_error(password)
        if password_issue:
            row_errors.append(password_issue)

        invitation_email = (
            str(row.invitation_email).lower().strip()
            if row.invitation_email
            else None
        )
        if payload.send_invitation:
            if not invitation_email:
                row_errors.append(
                    "Invitation email is required when sending invitations."
                )
            elif invitation_email.endswith(f"@{company_domain}"):
                row_errors.append(
                    "Use a personal email for invitations, not your company domain."
                )
            elif invitation_email in seen_invites:
                row_errors.append("Duplicate invitation email in this file.")
            else:
                seen_invites.add(invitation_email)

        if row_errors:
            errors.append(
                OrgMemberImportRowResult(
                    row=index,
                    email=work_email,
                    success=False,
                    message="; ".join(row_errors),
                )
            )
            continue

        normalized_rows.append(
            (
                index,
                OrgMemberCreate(
                    first_name=first_name,
                    last_name=last_name,
                    email=work_email,
                    invitation_email=invitation_email,
                    org_role=payload.org_role,
                    send_invitation=payload.send_invitation,
                    force_password_change=payload.force_password_change,
                    password=password,
                ),
            )
        )

    if normalized_rows:
        existing = await session.scalars(
            select(Account.email).where(
                func.lower(Account.email).in_(
                    [item[1].email.lower() for item in normalized_rows]
                )
            )
        )
        existing_emails = {email.lower() for email in existing.all()}
        if existing_emails:
            filtered: list[tuple[int, OrgMemberCreate]] = []
            for row_number, member_payload in normalized_rows:
                if member_payload.email.lower() in existing_emails:
                    errors.append(
                        OrgMemberImportRowResult(
                            row=row_number,
                            email=member_payload.email,
                            success=False,
                            message="That work email is already registered.",
                        )
                    )
                else:
                    filtered.append((row_number, member_payload))
            normalized_rows = filtered

    if errors and not normalized_rows:
        return OrgMemberImportResponse(
            created=[],
            errors=errors,
            created_count=0,
            error_count=len(errors),
        )

    created: list[OrgMemberRead] = []
    for row_number, member_payload in normalized_rows:
        try:
            member = await create_org_member(
                session,
                manager=manager,
                payload=member_payload,
            )
            created.append(member)
            errors.append(
                OrgMemberImportRowResult(
                    row=row_number,
                    email=member.email,
                    success=True,
                    message="Created",
                    invitation_sent=member.invitation_sent,
                )
            )
        except ValueError as error:
            errors.append(
                OrgMemberImportRowResult(
                    row=row_number,
                    email=member_payload.email,
                    success=False,
                    message=str(error),
                )
            )

    created_count = len(created)
    error_count = sum(1 for item in errors if not item.success)
    return OrgMemberImportResponse(
        created=created,
        errors=errors,
        created_count=created_count,
        error_count=error_count,
    )