-- Approval workflows for user registration and community creation
-- Supports "approval" mode for registration_mode and platform_mode settings

-- Pending user registrations (for approval mode)
CREATE TABLE pending_registrations (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    
    -- User data (not yet in users table)
    username VARCHAR(255) NOT NULL,
    email VARCHAR(255) NOT NULL,
    password_hash VARCHAR(255) NOT NULL,
    display_name VARCHAR(255),
    
    -- Invitation used (if any)
    invitation_id UUID REFERENCES invitations(id) ON DELETE SET NULL,
    
    -- Approval workflow
    status VARCHAR(50) DEFAULT 'pending' CHECK (status IN ('pending', 'approved', 'rejected')),
    reviewed_by UUID REFERENCES users(id) ON DELETE SET NULL,
    reviewed_at TIMESTAMPTZ,
    rejection_reason TEXT,
    
    -- Timestamps
    created_at TIMESTAMPTZ DEFAULT NOW(),
    expires_at TIMESTAMPTZ DEFAULT NOW() + INTERVAL '7 days',
    
    -- Prevent duplicates
    UNIQUE(username),
    UNIQUE(email)
);

-- Pending community creation requests (for approval mode)
CREATE TABLE pending_communities (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    
    -- Community data (not yet in communities table)
    name VARCHAR(255) NOT NULL,
    slug VARCHAR(255) NOT NULL,
    description TEXT,
    
    -- Requester
    requested_by UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    
    -- Approval workflow
    status VARCHAR(50) DEFAULT 'pending' CHECK (status IN ('pending', 'approved', 'rejected')),
    reviewed_by UUID REFERENCES users(id) ON DELETE SET NULL,
    reviewed_at TIMESTAMPTZ,
    rejection_reason TEXT,
    
    -- Timestamps
    created_at TIMESTAMPTZ DEFAULT NOW(),
    
    -- Prevent duplicate requests
    UNIQUE(slug)
);

-- Indexes
CREATE INDEX idx_pending_registrations_status ON pending_registrations(status);
CREATE INDEX idx_pending_registrations_email ON pending_registrations(email);
CREATE INDEX idx_pending_registrations_created ON pending_registrations(created_at DESC);

CREATE INDEX idx_pending_communities_status ON pending_communities(status);
CREATE INDEX idx_pending_communities_requested_by ON pending_communities(requested_by);
CREATE INDEX idx_pending_communities_created ON pending_communities(created_at DESC);

-- Function to approve a registration
CREATE OR REPLACE FUNCTION approve_registration(
    p_pending_id UUID,
    p_reviewer_id UUID
) RETURNS UUID AS $$
DECLARE
    v_pending pending_registrations%ROWTYPE;
    v_user_id UUID;
    v_user_count BIGINT;
BEGIN
    -- Get pending registration
    SELECT * INTO v_pending FROM pending_registrations WHERE id = p_pending_id AND status = 'pending';
    IF NOT FOUND THEN
        RAISE EXCEPTION 'Pending registration not found or already processed';
    END IF;
    
    -- Check if expired
    IF v_pending.expires_at < NOW() THEN
        UPDATE pending_registrations SET status = 'rejected', rejection_reason = 'Expired' WHERE id = p_pending_id;
        RAISE EXCEPTION 'Registration request has expired';
    END IF;
    
    -- Check if first user (should be admin)
    SELECT COUNT(*) INTO v_user_count FROM users;
    
    -- Create the user
    INSERT INTO users (username, email, password_hash, display_name, is_admin, invited_by)
    VALUES (v_pending.username, v_pending.email, v_pending.password_hash, v_pending.display_name, v_user_count = 0, v_pending.invitation_id)
    RETURNING id INTO v_user_id;
    
    -- Use invitation if provided
    IF v_pending.invitation_id IS NOT NULL THEN
        PERFORM use_invitation(
            (SELECT code FROM invitations WHERE id = v_pending.invitation_id),
            v_user_id,
            v_pending.email
        );
    END IF;
    
    -- Mark as approved
    UPDATE pending_registrations 
    SET status = 'approved', reviewed_by = p_reviewer_id, reviewed_at = NOW() 
    WHERE id = p_pending_id;
    
    RETURN v_user_id;
END;
$$ LANGUAGE plpgsql;

-- Function to reject a registration
CREATE OR REPLACE FUNCTION reject_registration(
    p_pending_id UUID,
    p_reviewer_id UUID,
    p_reason TEXT DEFAULT NULL
) RETURNS BOOLEAN AS $$
BEGIN
    UPDATE pending_registrations 
    SET status = 'rejected', 
        reviewed_by = p_reviewer_id, 
        reviewed_at = NOW(),
        rejection_reason = p_reason
    WHERE id = p_pending_id AND status = 'pending';
    
    RETURN FOUND;
END;
$$ LANGUAGE plpgsql;

-- Function to approve a community
CREATE OR REPLACE FUNCTION approve_community(
    p_pending_id UUID,
    p_reviewer_id UUID
) RETURNS UUID AS $$
DECLARE
    v_pending pending_communities%ROWTYPE;
    v_community_id UUID;
BEGIN
    -- Get pending community
    SELECT * INTO v_pending FROM pending_communities WHERE id = p_pending_id AND status = 'pending';
    IF NOT FOUND THEN
        RAISE EXCEPTION 'Pending community not found or already processed';
    END IF;
    
    -- Create the community
    INSERT INTO communities (name, slug, description, created_by, is_active)
    VALUES (v_pending.name, v_pending.slug, v_pending.description, v_pending.requested_by, true)
    RETURNING id INTO v_community_id;
    
    -- Add requester as admin
    INSERT INTO community_members (community_id, user_id, role)
    VALUES (v_community_id, v_pending.requested_by, 'admin');
    
    -- Mark as approved
    UPDATE pending_communities 
    SET status = 'approved', reviewed_by = p_reviewer_id, reviewed_at = NOW() 
    WHERE id = p_pending_id;
    
    RETURN v_community_id;
END;
$$ LANGUAGE plpgsql;

-- Function to reject a community
CREATE OR REPLACE FUNCTION reject_community(
    p_pending_id UUID,
    p_reviewer_id UUID,
    p_reason TEXT DEFAULT NULL
) RETURNS BOOLEAN AS $$
BEGIN
    UPDATE pending_communities 
    SET status = 'rejected', 
        reviewed_by = p_reviewer_id, 
        reviewed_at = NOW(),
        rejection_reason = p_reason
    WHERE id = p_pending_id AND status = 'pending';
    
    RETURN FOUND;
END;
$$ LANGUAGE plpgsql;

-- Cleanup expired pending registrations (to be run periodically)
CREATE OR REPLACE FUNCTION cleanup_expired_pending_registrations() RETURNS INTEGER AS $$
DECLARE
    deleted_count INTEGER;
BEGIN
    DELETE FROM pending_registrations WHERE expires_at < NOW() AND status = 'pending';
    GET DIAGNOSTICS deleted_count = ROW_COUNT;
    RETURN deleted_count;
END;
$$ LANGUAGE plpgsql;