-- Migration: create core community tables (communities, community_members, community_posts, community_comments)

CREATE TABLE `communities` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `course_id` int(11) NOT NULL,
  `cohort_id` int(11) DEFAULT NULL,
  `title` varchar(255) NOT NULL,
  `slug` varchar(255) NOT NULL,
  `description` text DEFAULT NULL,
  `visibility` enum('course','cohort','public') NOT NULL DEFAULT 'course',
  `status` enum('active','archived','hidden') NOT NULL DEFAULT 'active',
  `is_default` tinyint(1) NOT NULL DEFAULT 0,
  `created_by` int(11) NOT NULL,
  `created_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uniq_slug` (`slug`),
  KEY `idx_course_id` (`course_id`),
  KEY `idx_cohort_id` (`cohort_id`),
  KEY `idx_status` (`status`),
  KEY `idx_created_by` (`created_by`),
  CONSTRAINT `fk_communities_course_id` FOREIGN KEY (`course_id`) REFERENCES `courses` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_communities_cohort_id` FOREIGN KEY (`cohort_id`) REFERENCES `cohorts` (`id`) ON DELETE SET NULL,
  CONSTRAINT `fk_communities_created_by` FOREIGN KEY (`created_by`) REFERENCES `users` (`id`) ON DELETE RESTRICT
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE `community_members` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `community_id` int(11) NOT NULL,
  `user_id` int(11) NOT NULL,
  `role` enum('owner','moderator','member') NOT NULL DEFAULT 'member',
  `status` enum('active','banned','left') NOT NULL DEFAULT 'active',
  `joined_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uniq_member` (`community_id`,`user_id`),
  KEY `idx_user_id` (`user_id`),
  KEY `idx_status` (`status`),
  CONSTRAINT `fk_community_members_community_id` FOREIGN KEY (`community_id`) REFERENCES `communities` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_community_members_user_id` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE `community_posts` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `community_id` int(11) NOT NULL,
  `user_id` int(11) NOT NULL,
  `type` enum('discussion','project','assignment','announcement') NOT NULL DEFAULT 'discussion',
  `title` varchar(255) NOT NULL,
  `body` text NOT NULL,
  `attachments` json DEFAULT NULL,
  `related_course_id` int(11) DEFAULT NULL,
  `related_lesson_id` int(11) DEFAULT NULL,
  `status` enum('visible','hidden','deleted') NOT NULL DEFAULT 'visible',
  `is_pinned` tinyint(1) NOT NULL DEFAULT 0,
  `comment_count` int(11) NOT NULL DEFAULT 0,
  `created_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `idx_community_id` (`community_id`),
  KEY `idx_user_id` (`user_id`),
  KEY `idx_type` (`type`),
  KEY `idx_status_post` (`status`),
  KEY `idx_created_at_post` (`created_at`),
  KEY `idx_related_course_id` (`related_course_id`),
  KEY `idx_related_lesson_id` (`related_lesson_id`),
  CONSTRAINT `fk_community_posts_community_id` FOREIGN KEY (`community_id`) REFERENCES `communities` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_community_posts_user_id` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_community_posts_related_course_id` FOREIGN KEY (`related_course_id`) REFERENCES `courses` (`id`) ON DELETE SET NULL,
  CONSTRAINT `fk_community_posts_related_lesson_id` FOREIGN KEY (`related_lesson_id`) REFERENCES `course_lessons` (`id`) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE `community_comments` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `post_id` int(11) NOT NULL,
  `user_id` int(11) NOT NULL,
  `body` text NOT NULL,
  `parent_id` int(11) DEFAULT NULL,
  `status` enum('visible','hidden','deleted') NOT NULL DEFAULT 'visible',
  `created_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `idx_post_id` (`post_id`),
  KEY `idx_user_id_comment` (`user_id`),
  KEY `idx_parent_id` (`parent_id`),
  KEY `idx_status_comment` (`status`),
  CONSTRAINT `fk_community_comments_post_id` FOREIGN KEY (`post_id`) REFERENCES `community_posts` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_community_comments_user_id` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_community_comments_parent_id` FOREIGN KEY (`parent_id`) REFERENCES `community_comments` (`id`) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;