-- 微信扫码授权服务 — 数据库结构（阶段 1）
-- 目标环境：MySQL 8.0
-- 执行方式：mysql -u root -p < sql/schema.sql

CREATE DATABASE IF NOT EXISTS `wechat_api`
  DEFAULT CHARACTER SET utf8mb4
  DEFAULT COLLATE utf8mb4_unicode_ci;

USE `wechat_api`;

-- ---------------------------------------------------------------------------
-- 5.1 users — 用户表
-- ---------------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS `users` (
  `id`               BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  `openid`           VARCHAR(64)     NOT NULL                COMMENT '微信 OpenID',
  `nickname`         VARCHAR(100)    DEFAULT NULL            COMMENT '昵称（可选）',
  `created_at`       DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '首次关注时间',
  `last_seen_at`     DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '最近活跃时间',
  `has_claimed_free` TINYINT         NOT NULL DEFAULT 0      COMMENT '是否已领过免费授权',
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_openid` (`openid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='用户表';

-- ---------------------------------------------------------------------------
-- 5.2 authorizations — 授权表
-- ---------------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS `authorizations` (
  `id`               BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  `user_id`          BIGINT UNSIGNED NOT NULL                COMMENT '外键 users.id',
  `type`             ENUM('time','points') NOT NULL          COMMENT '授权类型',
  `start_at`         DATETIME        DEFAULT NULL            COMMENT '时间授权开始',
  `end_at`           DATETIME        DEFAULT NULL            COMMENT '时间授权结束',
  `remaining_points` INT             NOT NULL DEFAULT 0      COMMENT '积分余额',
  `total_points`     INT             NOT NULL DEFAULT 0      COMMENT '积分总量',
  `source`           ENUM('free','purchase','admin') NOT NULL COMMENT '来源',
  `status`           ENUM('pending','active','expired','exhausted','cancelled')
                                     NOT NULL DEFAULT 'pending' COMMENT '状态',
  `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_user_status` (`user_id`, `status`),
  CONSTRAINT `fk_auth_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='授权表';

-- ---------------------------------------------------------------------------
-- 5.3 auth_scenes — 扫码场景表
-- ---------------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS `auth_scenes` (
  `id`            BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  `scene_str`     VARCHAR(128)    NOT NULL                   COMMENT '二维码场景值',
  `device_id`     VARCHAR(128)    DEFAULT NULL               COMMENT 'MFC 设备标识',
  `status`        ENUM('pending','scanned','authorized','expired')
                                  NOT NULL DEFAULT 'pending' COMMENT '场景状态',
  `user_id`       BIGINT UNSIGNED DEFAULT NULL               COMMENT '扫码用户',
  `created_at`    DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `expires_at`    DATETIME        NOT NULL                   COMMENT '过期时间，默认 300 秒',
  `authorized_at` DATETIME        DEFAULT NULL               COMMENT '授权完成时间',
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_scene_str` (`scene_str`),
  KEY `idx_scene_status` (`scene_str`, `status`),
  CONSTRAINT `fk_scene_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='扫码场景表';

-- ---------------------------------------------------------------------------
-- 5.4 usage_logs — 使用日志
-- ---------------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS `usage_logs` (
  `id`               BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  `user_id`          BIGINT UNSIGNED NOT NULL,
  `device_id`        VARCHAR(128)    DEFAULT NULL,
  `authorization_id` BIGINT UNSIGNED DEFAULT NULL            COMMENT '本次扣减的授权',
  `cost_type`        ENUM('time','points') NOT NULL,
  `cost_points`      INT             NOT NULL DEFAULT 0      COMMENT '时间授权为 0',
  `used_at`          DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `idx_user_time` (`user_id`, `used_at`),
  CONSTRAINT `fk_log_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_log_auth` FOREIGN KEY (`authorization_id`) REFERENCES `authorizations` (`id`) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='使用日志';

-- ---------------------------------------------------------------------------
-- sessions — 会话令牌表（需求 9：session_token 服务端存储，有效期 24 小时）
-- ---------------------------------------------------------------------------
CREATE TABLE IF NOT EXISTS `sessions` (
  `id`         BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  `token`      VARCHAR(64)     NOT NULL                      COMMENT '随机生成的会话令牌',
  `user_id`    BIGINT UNSIGNED NOT NULL,
  `device_id`  VARCHAR(128)    DEFAULT NULL                  COMMENT '签发时绑定的设备',
  `scene_id`   BIGINT UNSIGNED DEFAULT NULL                  COMMENT '签发来源场景',
  `created_at` DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `expires_at` DATETIME        NOT NULL                      COMMENT '过期时间，默认 24 小时',
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk_token` (`token`),
  KEY `idx_session_user` (`user_id`),
  KEY `idx_session_scene` (`scene_id`),
  CONSTRAINT `fk_session_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_session_scene` FOREIGN KEY (`scene_id`) REFERENCES `auth_scenes` (`id`) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='会话令牌表';