-- ============================================================================
-- Migration 008: Academy (E-Learning / Compliance Academy) Schema
-- Compliance training courses, enrollments, and certificate management
-- ============================================================================

-- Academy courses table
CREATE TABLE IF NOT EXISTS academy_courses (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id UUID NOT NULL REFERENCES compliance_tenants(id) ON DELETE CASCADE,

    -- Course info
    title VARCHAR(255) NOT NULL,
    description TEXT,
    category VARCHAR(50) NOT NULL, -- 'dsgvo_basics', 'it_security', 'ai_literacy', 'whistleblower_protection', 'custom'
    duration_minutes INT DEFAULT 0,
    required_for_roles JSONB DEFAULT '[]', -- Array of role strings

    -- Status
    is_active BOOLEAN DEFAULT TRUE,

    -- Audit
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

-- Academy lessons table
CREATE TABLE IF NOT EXISTS academy_lessons (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    course_id UUID NOT NULL REFERENCES academy_courses(id) ON DELETE CASCADE,

    -- Lesson info
    title VARCHAR(255) NOT NULL,
    description TEXT,
    lesson_type VARCHAR(50) NOT NULL, -- 'video', 'text', 'quiz', 'interactive'
    content_url TEXT,
    duration_minutes INT DEFAULT 0,
    order_index INT DEFAULT 0,

    -- Quiz questions (only for lesson_type = 'quiz')
    quiz_questions JSONB DEFAULT '[]', -- Array of {question, options, correct_index, explanation}

    -- Audit
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

-- Academy enrollments table
CREATE TABLE IF NOT EXISTS academy_enrollments (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    tenant_id UUID NOT NULL REFERENCES compliance_tenants(id) ON DELETE CASCADE,
    course_id UUID NOT NULL REFERENCES academy_courses(id) ON DELETE CASCADE,
    user_id UUID NOT NULL,

    -- User info (denormalized for reporting)
    user_name VARCHAR(255) NOT NULL,
    user_email VARCHAR(255) NOT NULL,

    -- Progress tracking
    status VARCHAR(50) DEFAULT 'not_started', -- 'not_started', 'in_progress', 'completed', 'expired'
    progress_percent INT DEFAULT 0, -- 0-100
    current_lesson_index INT DEFAULT 0,

    -- Timestamps
    started_at TIMESTAMPTZ,
    completed_at TIMESTAMPTZ,
    deadline TIMESTAMPTZ,

    -- Audit
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

-- Academy certificates table
CREATE TABLE IF NOT EXISTS academy_certificates (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    enrollment_id UUID NOT NULL UNIQUE REFERENCES academy_enrollments(id) ON DELETE CASCADE,

    -- Certificate info
    user_name VARCHAR(255) NOT NULL,
    course_title VARCHAR(255) NOT NULL,
    issued_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    valid_until TIMESTAMPTZ,
    pdf_url TEXT,

    -- Audit
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

-- ============================================================================
-- Indexes
-- ============================================================================

-- Course indexes
CREATE INDEX IF NOT EXISTS idx_academy_courses_tenant ON academy_courses(tenant_id);
CREATE INDEX IF NOT EXISTS idx_academy_courses_category ON academy_courses(tenant_id, category);
CREATE INDEX IF NOT EXISTS idx_academy_courses_active ON academy_courses(tenant_id, is_active);

-- Lesson indexes
CREATE INDEX IF NOT EXISTS idx_academy_lessons_course ON academy_lessons(course_id);
CREATE INDEX IF NOT EXISTS idx_academy_lessons_order ON academy_lessons(course_id, order_index);

-- Enrollment indexes
CREATE INDEX IF NOT EXISTS idx_academy_enrollments_tenant ON academy_enrollments(tenant_id);
CREATE INDEX IF NOT EXISTS idx_academy_enrollments_course ON academy_enrollments(course_id);
CREATE INDEX IF NOT EXISTS idx_academy_enrollments_user ON academy_enrollments(user_id);
CREATE INDEX IF NOT EXISTS idx_academy_enrollments_status ON academy_enrollments(tenant_id, status);
CREATE INDEX IF NOT EXISTS idx_academy_enrollments_deadline ON academy_enrollments(deadline) WHERE deadline IS NOT NULL AND status NOT IN ('completed', 'expired');
CREATE INDEX IF NOT EXISTS idx_academy_enrollments_tenant_course ON academy_enrollments(tenant_id, course_id);

-- Certificate indexes
CREATE INDEX IF NOT EXISTS idx_academy_certificates_enrollment ON academy_certificates(enrollment_id);
CREATE INDEX IF NOT EXISTS idx_academy_certificates_valid_until ON academy_certificates(valid_until) WHERE valid_until IS NOT NULL;

-- ============================================================================
-- Triggers
-- ============================================================================

-- Reuse existing update_updated_at_column function

-- Courses trigger
DROP TRIGGER IF EXISTS update_academy_courses_updated_at ON academy_courses;
CREATE TRIGGER update_academy_courses_updated_at
    BEFORE UPDATE ON academy_courses
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

-- Lessons trigger
DROP TRIGGER IF EXISTS update_academy_lessons_updated_at ON academy_lessons;
CREATE TRIGGER update_academy_lessons_updated_at
    BEFORE UPDATE ON academy_lessons
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

-- Enrollments trigger
DROP TRIGGER IF EXISTS update_academy_enrollments_updated_at ON academy_enrollments;
CREATE TRIGGER update_academy_enrollments_updated_at
    BEFORE UPDATE ON academy_enrollments
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

-- Certificates trigger
DROP TRIGGER IF EXISTS update_academy_certificates_updated_at ON academy_certificates;
CREATE TRIGGER update_academy_certificates_updated_at
    BEFORE UPDATE ON academy_certificates
    FOR EACH ROW EXECUTE FUNCTION update_updated_at_column();

-- ============================================================================
-- Comments
-- ============================================================================

COMMENT ON TABLE academy_courses IS 'Compliance training courses (DSGVO, IT-Security, AI Literacy, Whistleblower)';
COMMENT ON TABLE academy_lessons IS 'Individual lessons within a course (video, text, quiz, interactive)';
COMMENT ON TABLE academy_enrollments IS 'User enrollments in courses with progress tracking';
COMMENT ON TABLE academy_certificates IS 'Completion certificates issued for finished enrollments';

COMMENT ON COLUMN academy_courses.category IS 'Course category: dsgvo_basics, it_security, ai_literacy, whistleblower_protection, custom';
COMMENT ON COLUMN academy_courses.required_for_roles IS 'JSON array of role names that are required to complete this course';
COMMENT ON COLUMN academy_lessons.quiz_questions IS 'JSON array of quiz questions: [{question, options, correct_index, explanation}]';
COMMENT ON COLUMN academy_enrollments.status IS 'Enrollment status: not_started, in_progress, completed, expired';
COMMENT ON COLUMN academy_enrollments.progress_percent IS 'Course completion percentage (0-100)';
COMMENT ON COLUMN academy_certificates.enrollment_id IS 'One-to-one relationship with enrollment (UNIQUE constraint)';