-- =====================================================
-- TABLE: education.lessons
-- =====================================================
-- Proyecto: OrbiQuant IA (Trading Platform)
-- Módulo: OQI-002 - Education
-- Especificación: ET-EDU-001-database.md
-- =====================================================

CREATE TABLE education.lessons (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),

  -- Relación con módulo
  module_id UUID NOT NULL REFERENCES education.modules(id) ON DELETE CASCADE,

  -- Información básica
  title VARCHAR(200) NOT NULL,
  description TEXT,

  -- Tipo de contenido
  content_type education.lesson_content_type NOT NULL DEFAULT 'video',

  -- Contenido video
  video_url VARCHAR(500), -- URL de Vimeo/S3
  video_duration_seconds INTEGER,
  video_provider VARCHAR(50), -- 'vimeo', 's3', etc.
  video_id VARCHAR(200), -- ID del video en el provider

  -- Contenido texto/article
  article_content TEXT,

  -- Recursos adicionales
  attachments JSONB, -- [{name, url, type, size}]

  -- Ordenamiento
  display_order INTEGER NOT NULL DEFAULT 0,

  -- Configuración
  is_preview BOOLEAN DEFAULT false, -- Puede verse sin enrollment
  is_mandatory BOOLEAN DEFAULT true, -- Requerido para completar el curso

  -- Gamificación
  xp_reward INTEGER DEFAULT 10, -- XP al completar la lección

  -- Metadata
  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),

  CONSTRAINT unique_module_order UNIQUE(module_id, display_order),
  CONSTRAINT video_fields_required CHECK (
    (content_type != 'video') OR
    (video_url IS NOT NULL AND video_duration_seconds IS NOT NULL)
  )
);

-- Índices
CREATE INDEX idx_lessons_module ON education.lessons(module_id);
CREATE INDEX idx_lessons_order ON education.lessons(module_id, display_order);
CREATE INDEX idx_lessons_type ON education.lessons(content_type);
CREATE INDEX idx_lessons_preview ON education.lessons(is_preview) WHERE is_preview = true;

-- Comentarios
COMMENT ON TABLE education.lessons IS 'Lecciones individuales dentro de módulos';
COMMENT ON COLUMN education.lessons.attachments IS 'Archivos adjuntos en formato JSON: [{name, url, type, size}]';
COMMENT ON COLUMN education.lessons.is_preview IS 'Puede verse sin enrollment (preview gratuito)';
COMMENT ON COLUMN education.lessons.is_mandatory IS 'Requerido para completar el curso';
COMMENT ON COLUMN education.lessons.xp_reward IS 'XP otorgado al completar la lección';