-- 创建任务表
CREATE TABLE `tasks` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `title` VARCHAR(200) NOT NULL COMMENT '任务标题',
  `description` TEXT COMMENT '任务描述',
  `priority` ENUM('low', 'medium', 'high') DEFAULT 'medium' COMMENT '优先级',
  `status` ENUM('pending', 'ongoing', 'completed', 'expired') DEFAULT 'pending' COMMENT '任务状态',
  `creator_id` INT NOT NULL COMMENT '创建人ID',
  `deadline` DATETIME COMMENT '截止时间',
  `requirements` JSON COMMENT '任务要求配置',
  `progress` INT DEFAULT 0 COMMENT '完成进度(0-100)',
  `created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `is_deleted` BOOLEAN DEFAULT FALSE,
  INDEX `idx_status` (`status`),
  INDEX `idx_creator` (`creator_id`),
  INDEX `idx_deadline` (`deadline`),
  FOREIGN KEY (`creator_id`) REFERENCES `users`(`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='任务表';

-- 创建任务课程关联表
CREATE TABLE `task_courses` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `task_id` INT NOT NULL COMMENT '任务ID',
  `course_id` INT NOT NULL COMMENT '课程ID',
  `created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  UNIQUE KEY `uk_task_course` (`task_id`, `course_id`),
  FOREIGN KEY (`task_id`) REFERENCES `tasks`(`id`) ON DELETE CASCADE,
  FOREIGN KEY (`course_id`) REFERENCES `courses`(`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='任务课程关联表';

-- 创建任务分配表
CREATE TABLE `task_assignments` (
  `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `task_id` INT NOT NULL COMMENT '任务ID',
  `user_id` INT NOT NULL COMMENT '分配用户ID',
  `team_id` INT DEFAULT NULL COMMENT '团队ID（如果按团队分配）',
  `status` ENUM('not_started', 'in_progress', 'completed') DEFAULT 'not_started' COMMENT '完成状态',
  `progress` INT DEFAULT 0 COMMENT '个人完成进度(0-100)',
  `completed_at` DATETIME COMMENT '完成时间',
  `created_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  UNIQUE KEY `uk_task_user` (`task_id`, `user_id`),
  INDEX `idx_status` (`status`),
  FOREIGN KEY (`task_id`) REFERENCES `tasks`(`id`) ON DELETE CASCADE,
  FOREIGN KEY (`user_id`) REFERENCES `users`(`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='任务分配表';