-- v0.12.3: Formation & Éducation (F276-F305)
-- Courses, lessons, enrollments, progress, certificates, reviews

-- Courses catalog
CREATE TABLE IF NOT EXISTS courses (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    creator_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    title VARCHAR(255) NOT NULL,
    slug VARCHAR(255) NOT NULL UNIQUE,
    description TEXT NOT NULL DEFAULT '',
    category VARCHAR(100),
    tags VARCHAR(50)[] DEFAULT '{}',
    cover_image_url TEXT,
    price_cents INTEGER NOT NULL DEFAULT 0,
    currency VARCHAR(3) NOT NULL DEFAULT 'USD',
    pricing_model VARCHAR(50) NOT NULL DEFAULT 'fixed',
    minimum_price_cents INTEGER DEFAULT 0,
    status VARCHAR(50) NOT NULL DEFAULT 'draft',
    level VARCHAR(50) DEFAULT 'beginner',
    language VARCHAR(5) DEFAULT 'en',
    total_duration_seconds INTEGER NOT NULL DEFAULT 0,
    lesson_count INTEGER NOT NULL DEFAULT 0,
    enrollment_count INTEGER NOT NULL DEFAULT 0,
    review_count INTEGER NOT NULL DEFAULT 0,
    average_rating NUMERIC(3,2) DEFAULT 0,
    published_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    deleted_at TIMESTAMPTZ
);

CREATE INDEX IF NOT EXISTS idx_courses_creator ON courses(creator_id);
CREATE INDEX IF NOT EXISTS idx_courses_status ON courses(status, published_at DESC);
CREATE INDEX IF NOT EXISTS idx_courses_category ON courses(category);
CREATE INDEX IF NOT EXISTS idx_courses_slug ON courses(slug);

-- Course lessons
CREATE TABLE IF NOT EXISTS lessons (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    course_id UUID NOT NULL REFERENCES courses(id) ON DELETE CASCADE,
    order_index INTEGER NOT NULL,
    title VARCHAR(255) NOT NULL,
    description TEXT,
    video_file_path VARCHAR(512),
    duration_seconds INTEGER NOT NULL DEFAULT 0,
    is_preview_free BOOLEAN NOT NULL DEFAULT false,
    transcoding_status VARCHAR(50) NOT NULL DEFAULT 'pending',
    hls_master_playlist_url TEXT,
    thumbnail_url TEXT,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),

    CONSTRAINT uq_lesson_order UNIQUE (course_id, order_index),
    CONSTRAINT chk_order_positive CHECK (order_index > 0)
);

CREATE INDEX IF NOT EXISTS idx_lessons_course_order ON lessons(course_id, order_index);
CREATE INDEX IF NOT EXISTS idx_lessons_transcoding ON lessons(transcoding_status);

-- Course enrollments (purchases)
CREATE TABLE IF NOT EXISTS course_enrollments (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    course_id UUID NOT NULL REFERENCES courses(id) ON DELETE CASCADE,
    purchased_price_cents INTEGER NOT NULL DEFAULT 0,
    currency VARCHAR(3) NOT NULL DEFAULT 'USD',
    status VARCHAR(50) NOT NULL DEFAULT 'active',
    access_expires_at TIMESTAMPTZ,
    purchased_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    refunded_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),

    CONSTRAINT uq_enrollment_user_course UNIQUE (user_id, course_id)
);

CREATE INDEX IF NOT EXISTS idx_enrollments_user ON course_enrollments(user_id, purchased_at DESC);
CREATE INDEX IF NOT EXISTS idx_enrollments_course ON course_enrollments(course_id, status);

-- Lesson progress per user
CREATE TABLE IF NOT EXISTS lesson_progress (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    lesson_id UUID NOT NULL REFERENCES lessons(id) ON DELETE CASCADE,
    enrollment_id UUID NOT NULL REFERENCES course_enrollments(id) ON DELETE CASCADE,
    watched_percentage INTEGER DEFAULT 0,
    watched_duration_seconds INTEGER DEFAULT 0,
    playback_position_seconds INTEGER DEFAULT 0,
    is_completed BOOLEAN NOT NULL DEFAULT false,
    completed_at TIMESTAMPTZ,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),

    CONSTRAINT uq_progress_user_lesson UNIQUE (user_id, lesson_id),
    CONSTRAINT chk_percentage CHECK (watched_percentage >= 0 AND watched_percentage <= 100)
);

CREATE INDEX IF NOT EXISTS idx_progress_enrollment ON lesson_progress(enrollment_id);

-- Completion certificates (declarative, not gamified)
CREATE TABLE IF NOT EXISTS certificates (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    course_id UUID NOT NULL REFERENCES courses(id) ON DELETE CASCADE,
    enrollment_id UUID NOT NULL REFERENCES course_enrollments(id) ON DELETE CASCADE,
    certificate_code VARCHAR(255) NOT NULL UNIQUE,
    issue_date TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    status VARCHAR(50) NOT NULL DEFAULT 'active',
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),

    CONSTRAINT uq_cert_user_course UNIQUE (user_id, course_id)
);

CREATE INDEX IF NOT EXISTS idx_certificates_code ON certificates(certificate_code);

-- Course reviews
CREATE TABLE IF NOT EXISTS course_reviews (
    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
    course_id UUID NOT NULL REFERENCES courses(id) ON DELETE CASCADE,
    user_id UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
    enrollment_id UUID NOT NULL REFERENCES course_enrollments(id),
    rating INTEGER NOT NULL,
    title VARCHAR(255),
    content TEXT NOT NULL,
    status VARCHAR(50) NOT NULL DEFAULT 'approved',
    helpful_count INTEGER NOT NULL DEFAULT 0,
    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
    deleted_at TIMESTAMPTZ,

    CONSTRAINT uq_review_user_course UNIQUE (user_id, course_id),
    CONSTRAINT chk_rating CHECK (rating >= 1 AND rating <= 5)
);

CREATE INDEX IF NOT EXISTS idx_reviews_course ON course_reviews(course_id, rating DESC);