-- Security Awareness Learning Platform Database Schema
-- PostgreSQL 15+

-- Events table: Represents training events/sessions
CREATE TABLE events (
    id SERIAL PRIMARY KEY,
    name VARCHAR(255) NOT NULL,
    description TEXT,
    start_date TIMESTAMP,
    end_date TIMESTAMP,
    is_active BOOLEAN DEFAULT true,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Participants table: Anonymous participants with pseudonyms
CREATE TABLE participants (
    id SERIAL PRIMARY KEY,
    pseudonym VARCHAR(100) NOT NULL,
    event_id INTEGER NOT NULL REFERENCES events(id) ON DELETE CASCADE,
    session_token VARCHAR(255) UNIQUE NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    last_active TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(pseudonym, event_id)
);

-- Lessons table: Catalog of available lessons
CREATE TABLE lessons (
    id SERIAL PRIMARY KEY,
    lesson_key VARCHAR(100) UNIQUE NOT NULL,
    title VARCHAR(255) NOT NULL,
    description TEXT,
    module_path VARCHAR(255) NOT NULL,
    config_path VARCHAR(255) NOT NULL,
    difficulty_level VARCHAR(50),
    estimated_duration INTEGER,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

-- Event_Lessons table: Lessons assigned to events with configuration
CREATE TABLE event_lessons (
    id SERIAL PRIMARY KEY,
    event_id INTEGER NOT NULL REFERENCES events(id) ON DELETE CASCADE,
    lesson_id INTEGER NOT NULL REFERENCES lessons(id) ON DELETE CASCADE,
    order_index INTEGER NOT NULL,
    max_points INTEGER NOT NULL DEFAULT 100,
    weight DECIMAL(5,2) DEFAULT 1.0,
    is_required BOOLEAN DEFAULT true,
    unlock_after_lesson_id INTEGER REFERENCES lessons(id),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(event_id, lesson_id),
    UNIQUE(event_id, order_index)
);

-- Lesson_Progress table: Tracks participant progress through lessons
CREATE TABLE lesson_progress (
    id SERIAL PRIMARY KEY,
    participant_id INTEGER NOT NULL REFERENCES participants(id) ON DELETE CASCADE,
    event_lesson_id INTEGER NOT NULL REFERENCES event_lessons(id) ON DELETE CASCADE,
    status VARCHAR(50) NOT NULL DEFAULT 'not_started',
    started_at TIMESTAMP,
    completed_at TIMESTAMP,
    score INTEGER DEFAULT 0,
    attempts INTEGER DEFAULT 0,
    current_step INTEGER DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    UNIQUE(participant_id, event_lesson_id),
    CHECK (status IN ('not_started', 'in_progress', 'completed'))
);

-- Lesson_Answers table: Stores participant answers
CREATE TABLE lesson_answers (
    id SERIAL PRIMARY KEY,
    lesson_progress_id INTEGER NOT NULL REFERENCES lesson_progress(id) ON DELETE CASCADE,
    question_key VARCHAR(100) NOT NULL,
    answer_data JSONB NOT NULL,
    is_correct BOOLEAN,
    points_awarded INTEGER DEFAULT 0,
    submitted_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    feedback TEXT
);

-- Admin_Users table: Admin authentication
CREATE TABLE admin_users (
    id SERIAL PRIMARY KEY,
    username VARCHAR(100) UNIQUE NOT NULL,
    password_hash VARCHAR(255) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    last_login TIMESTAMP
);

-- Indexes for performance
CREATE INDEX idx_participants_event ON participants(event_id);
CREATE INDEX idx_participants_session ON participants(session_token);
CREATE INDEX idx_participants_pseudonym ON participants(pseudonym);
CREATE INDEX idx_event_lessons_event ON event_lessons(event_id);
CREATE INDEX idx_event_lessons_lesson ON event_lessons(lesson_id);
CREATE INDEX idx_event_lessons_order ON event_lessons(event_id, order_index);
CREATE INDEX idx_lesson_progress_participant ON lesson_progress(participant_id);
CREATE INDEX idx_lesson_progress_event_lesson ON lesson_progress(event_lesson_id);
CREATE INDEX idx_lesson_progress_status ON lesson_progress(status);
CREATE INDEX idx_lesson_answers_progress ON lesson_answers(lesson_progress_id);
CREATE INDEX idx_lesson_answers_question ON lesson_answers(question_key);

-- Trigger function to update updated_at timestamps
CREATE OR REPLACE FUNCTION update_updated_at_column()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = CURRENT_TIMESTAMP;
    RETURN NEW;
END;
$$ language 'plpgsql';

-- Apply triggers to tables
CREATE TRIGGER update_events_updated_at BEFORE UPDATE ON events
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

CREATE TRIGGER update_lessons_updated_at BEFORE UPDATE ON lessons
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

CREATE TRIGGER update_lesson_progress_updated_at BEFORE UPDATE ON lesson_progress
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

-- Insert default admin user (password: admin123 - CHANGE IN PRODUCTION!)
-- bcrypt hash for 'admin123' with 10 rounds
INSERT INTO admin_users (username, password_hash) VALUES
('admin', '$2b$10$mP8BvCik6In9lvWqxV57VuKglR3IqW4GfMoF.5fsT8HrTxRqscElW');

-- Comments for documentation
COMMENT ON TABLE events IS 'Training events or sessions that participants can join';
COMMENT ON TABLE participants IS 'Anonymous participants identified by pseudonym within events';
COMMENT ON TABLE lessons IS 'Catalog of available lesson modules';
COMMENT ON TABLE event_lessons IS 'Lessons assigned to specific events with custom configuration';
COMMENT ON TABLE lesson_progress IS 'Tracks individual participant progress through lessons';
COMMENT ON TABLE lesson_answers IS 'Stores submitted answers with scoring information';
COMMENT ON TABLE admin_users IS 'Administrative users with full system access';