"""Migrate guest_users to regular users with role='guest' and drop guest tables.

⚠️ Guest-System umgebaut — Guests sind jetzt reguläre User mit role=guest

This migration:
1. Creates User records for each guest (or links to existing users by email)
2. Creates UserTenant records with role='guest' and appropriate status
3. Drops guest_invitations and guest_users tables

After this migration, guests authenticate via the normal login flow and are
managed through the regular user system with role='guest' in user_tenants.

Revision ID: 0113
Revises: 0112
"""

from __future__ import annotations

from alembic import op

revision = "0113"
down_revision = "0112"
branch_labels = None
depends_on = None


def upgrade() -> None:
    # Migrate guest_users into users + user_tenants with role='guest'
    op.execute("""
DO $$
DECLARE
    guest_rec RECORD;
    existing_user_id UUID;
    new_user_id UUID;
    mapped_status TEXT;
BEGIN
    FOR guest_rec IN SELECT * FROM guest_users
    LOOP
        -- Map guest status to user_tenants status
        mapped_status := CASE
            WHEN guest_rec.status = 'active' THEN 'active'
            WHEN guest_rec.status = 'invited' THEN 'invited'
            WHEN guest_rec.status = 'expired' THEN 'disabled'
            WHEN guest_rec.status = 'revoked' THEN 'disabled'
            ELSE 'disabled'
        END;

        -- Check if a user with this email already exists
        SELECT id INTO existing_user_id
        FROM users
        WHERE email = guest_rec.email
        LIMIT 1;

        IF existing_user_id IS NOT NULL THEN
            -- User already exists — just create the tenant membership if missing
            new_user_id := existing_user_id;

            -- Check if user_tenants entry already exists for this user+tenant
            IF NOT EXISTS (
                SELECT 1 FROM user_tenants
                WHERE user_id = new_user_id
                  AND tenant_id = guest_rec.tenant_id
            ) THEN
                INSERT INTO user_tenants (user_id, tenant_id, is_default, role, status, created_at, updated_at)
                VALUES (
                    new_user_id,
                    guest_rec.tenant_id,
                    false,
                    'guest',
                    mapped_status,
                    guest_rec.created_at,
                    guest_rec.updated_at
                );
            END IF;
        ELSE
            -- Create new user from guest record
            INSERT INTO users (id, email, name, password_hash, is_active, preferences, is_system_admin, created_at, updated_at)
            VALUES (
                gen_random_uuid(),
                guest_rec.email,
                guest_rec.name,
                COALESCE(guest_rec.password_hash, ''),
                true,
                '{}'::jsonb,
                false,
                guest_rec.created_at,
                guest_rec.updated_at
            )
            RETURNING id INTO new_user_id;

            -- Create user_tenants membership with guest role
            INSERT INTO user_tenants (user_id, tenant_id, is_default, role, status, created_at, updated_at)
            VALUES (
                new_user_id,
                guest_rec.tenant_id,
                false,
                'guest',
                mapped_status,
                guest_rec.created_at,
                guest_rec.updated_at
            );
        END IF;
    END LOOP;
END $$;
    """)

    # Drop guest tables
    op.execute("DROP TABLE IF EXISTS guest_invitations CASCADE")
    op.execute("DROP TABLE IF EXISTS guest_users CASCADE")


def downgrade() -> None:
    # Recreate guest_users table (data is lost — this is a one-way migration)
    op.execute("""
    CREATE TABLE IF NOT EXISTS guest_users (
        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
        email VARCHAR(255) NOT NULL,
        name VARCHAR(255) NOT NULL,
        password_hash VARCHAR(255),
        tenant_id UUID NOT NULL REFERENCES tenants(id) ON DELETE CASCADE,
        invited_by UUID REFERENCES users(id) ON DELETE SET NULL,
        status VARCHAR(20) NOT NULL DEFAULT 'invited',
        expires_at TIMESTAMPTZ,
        created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
        updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
    )
    """)
    op.execute("""
    CREATE TABLE IF NOT EXISTS guest_invitations (
        id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
        guest_user_id UUID NOT NULL REFERENCES guest_users(id) ON DELETE CASCADE,
        token_hash VARCHAR(64) NOT NULL UNIQUE,
        expires_at TIMESTAMPTZ NOT NULL,
        used_at TIMESTAMPTZ,
        revoked_at TIMESTAMPTZ,
        created_by UUID REFERENCES users(id) ON DELETE SET NULL,
        created_at TIMESTAMPTZ NOT NULL DEFAULT now()
    )
    """)