package devstar_devcontainer

import (
	"code.gitea.io/gitea/models/db"
	devstar_devcontainer_models "code.gitea.io/gitea/models/devstar_devcontainer"
	"code.gitea.io/gitea/modules/log"
	DevcontainersVO "code.gitea.io/gitea/routers/web/devcontainer/vo"
	"context"
	"fmt"
	"github.com/google/uuid"
	"regexp"
	"strings"
	"xorm.io/builder"
)

// GetRepoDevcontainerDetails 获取仓库对应 DevContainer 信息
func GetRepoDevcontainerDetails(ctx context.Context, opts *DevcontainersVO.RepoDevcontainerOptions) (DevcontainersVO.RepoDevContainerVO, error) {

	// 0. 构造异常返回时候的空数据
	resultRepoDevcontainerDetail := DevcontainersVO.RepoDevContainerVO{}

	// 1. 检查参数是否有效
	if opts == nil || opts.Actor == nil || opts.Repository == nil {
		return resultRepoDevcontainerDetail, devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
			Action:  "construct query condition for devContainer user list",
			Message: "invalid search condition",
		}
	}

	// 2. 查询数据库
	/*
		SELECT
			devstar_devcontainer.id                                   AS devcontainer_id,
			devstar_devcontainer.name                                 AS devcontainer_name,
			devstar_devcontainer.devcontainer_host                    AS devcontainer_host,
			devstar_devcontainer.devcontainer_port                    AS devcontainer_port,
			devstar_devcontainer.devcontainer_username                AS devcontainer_username,
			devstar_devcontainer.devcontainer_password                AS devcontainer_password,
			devstar_devcontainer.devcontainer_work_dir                AS devcontainer_work_dir,
			devstar_devcontainer.repo_id                              AS repo_id,
			repository.name                                           AS repo_name,
			repository.owner_name                                     AS repo_owner_name,
			repository.description                                    AS repo_description,
			CONCAT('/', repository.owner_name, '/', repository.name)  AS repo_link
		FROM devstar_devcontainer
		INNER JOIN repository on devstar_devcontainer.repo_id = repository.id
		WHERE
				devstar_devcontainer.user_id = #{opts.Actor.ID}
			AND
				devstar_devcontainer.repo_id = #{opts.Repository.ID};
	*/
	_, err := db.GetEngine(ctx).
		Table("devstar_devcontainer").
		Select(""+
			"devstar_devcontainer.id                                   AS devcontainer_id,"+
			"devstar_devcontainer.name                                 AS devcontainer_name,"+
			"devstar_devcontainer.devcontainer_host                    AS devcontainer_host,"+
			"devstar_devcontainer.devcontainer_port                    AS devcontainer_port,"+
			"devstar_devcontainer.devcontainer_username                AS devcontainer_username,"+
			"devstar_devcontainer.devcontainer_password                AS devcontainer_password,"+
			"devstar_devcontainer.devcontainer_work_dir                AS devcontainer_work_dir,"+
			"devstar_devcontainer.repo_id                              AS repo_id,"+
			"repository.name                                           AS repo_name,"+
			"repository.owner_name                                     AS repo_owner_name,"+
			"repository.description                                    AS repo_description,"+
			"CONCAT('/', repository.owner_name, '/', repository.name)  AS repo_link").
		Join("INNER", "repository", "devstar_devcontainer.repo_id = repository.id").
		Where("devstar_devcontainer.user_id = ? AND devstar_devcontainer.repo_id = ?", opts.Actor.ID, opts.Repository.ID).
		Get(&resultRepoDevcontainerDetail)

	// 3. 返回
	if err != nil {
		return resultRepoDevcontainerDetail, devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
			Action:  fmt.Sprintf("query devcontainer with repo '%v' and username '%v'", opts.Repository.Name, opts.Actor.Name),
			Message: err.Error(),
		}
	}
	return resultRepoDevcontainerDetail, nil
}

// CreateRepoDevcontainer 创建 DevContainer
/*
   必要假设：前置中间件已完成检查，确保数据有效：
   - 当前用户为已登录用户
   - 当前用户拥有 repo code写入权限
   - 数据库此前不存在 该用户在该repo创建的 Dev Container
*/
func CreateRepoDevcontainer(ctx context.Context, opts *DevcontainersVO.RepoDevcontainerOptions) error {
	// TODO: 调用 k8s client 创建
	// 目前只是 mock数据
	username := opts.Actor.Name
	repoName := opts.Repository.Name
	newDevcontainer := &devstar_devcontainer_models.DevstarDevcontainer{
		Name:                 getSanitizedDevcontainerName(username, repoName),
		DevcontainerHost:     "127.0.0.1",
		DevcontainerPort:     10086,
		DevcontainerUsername: "mock-username",
		DevcontainerPassword: "mock-password",
		DevcontainerWorkDir:  "~/workspace/",
		RepoId:               opts.Repository.ID,
		UserId:               opts.Actor.ID,
	}

	// 在数据库事务中创建 Dev Container 分配资源，出错时自动回滚相对应数据库字段，保证数据一致
	dbTransactionErr := db.WithTx(ctx, func(ctx context.Context) error {
		rowsAffect, err := db.GetEngine(ctx).
			Table("devstar_devcontainer").
			Insert(newDevcontainer)

		if err != nil {
			return devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
				Action:  fmt.Sprintf("insert new DevContainer for user '%s' in repo '%s'", username, repoName),
				Message: err.Error(),
			}
		} else if rowsAffect == 0 {
			return devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
				Action:  fmt.Sprintf("insert new DevContainer for user '%s' in repo '%s'", username, repoName),
				Message: "expected 1 row to be inserted, but got 0",
			}
		}

		err = claimDevcontainerResource(newDevcontainer)
		if err != nil {
			return devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
				Action:  fmt.Sprintf("Failed to claim resource for Dev Container devstar_devcontainer.DevstarDevcontainer %v", newDevcontainer),
				Message: err.Error(),
			}
		}
		return nil
	})

	return dbTransactionErr
}

// DeleteRepoDevcontainer 按照 仓库 和/或 用户信息删除 DevContainer(s)
func DeleteRepoDevcontainer(ctx context.Context, opts *DevcontainersVO.RepoDevcontainerOptions) error {
	if ctx == nil || opts == nil || (opts.Actor == nil && opts.Repository == nil) {
		return devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
			Action:  "construct query parameters",
			Message: "Invalid parameters",
		}
	}

	// 1. 构造查询条件
	sqlDevcontainerCondition := builder.NewCond()
	if opts.Actor != nil {
		sqlDevcontainerCondition = sqlDevcontainerCondition.And(builder.Eq{"user_id": opts.Actor.ID})
	}
	if opts.Repository != nil {
		sqlDevcontainerCondition = sqlDevcontainerCondition.And(builder.Eq{"repo_id": opts.Repository.ID})
	}
	var devcontainersList []devstar_devcontainer_models.DevstarDevcontainer

	// 2. 开启事务：先获取 devcontainer列表，后删除
	dbTransactionErr := db.WithTx(ctx, func(ctx context.Context) error {
		var err error
		// 2.1 条件查询： user_id 和/或 repo_id
		err = db.GetEngine(ctx).
			Table("devstar_devcontainer").
			Where(sqlDevcontainerCondition).
			Find(&devcontainersList)
		if err != nil {
			return devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
				Action:  fmt.Sprintf("find devcontainer(s) with condition '%v'", sqlDevcontainerCondition),
				Message: err.Error(),
			}
		}

		// 2.2 条件删除： user_id 和/或 repo_id
		_, err = db.GetEngine(ctx).
			Table("devstar_devcontainer").
			Where(sqlDevcontainerCondition).
			Delete()
		if err != nil {
			return devstar_devcontainer_models.ErrFailedToOperateDevstarDevcontainerDB{
				Action:  fmt.Sprintf("MARK devcontainer(s) as DELETED with condition '%v'", sqlDevcontainerCondition),
				Message: err.Error(),
			}
		}

		return nil
	})

	if dbTransactionErr != nil {
		return dbTransactionErr
	}

	// 3. 后台启动一个goroutine慢慢回收 Dev Container 资源 (如果回收失败，将会产生孤儿 Dev Container，只能管理员手动识别、删除)
	go func() {
		_ = purgeDevcontainersResource(devcontainersList)
	}()

	return dbTransactionErr
}

// getSanitizedDevcontainerName 辅助获取当前用户在当前仓库创建的 devContainer名称
// DevContainer命名规则： 用户名、仓库名各由小于15位的小写字母和数字组成，中间使用'-'分隔，后面使用'-'分隔符拼接32位UUID小写字母数字字符串
func getSanitizedDevcontainerName(username, repoName string) string {
	regexpNonAlphaNum := regexp.MustCompile(`[^a-zA-Z0-9]`)
	sanitizedUsername := regexpNonAlphaNum.ReplaceAllString(username, "")
	sanitizedRepoName := regexpNonAlphaNum.ReplaceAllString(repoName, "")
	if len(sanitizedUsername) > 15 {
		sanitizedUsername = strings.ToLower(sanitizedUsername[:15])
	}
	if len(sanitizedRepoName) > 15 {
		sanitizedRepoName = strings.ToLower(sanitizedRepoName[:15])
	}
	newUUID, _ := uuid.NewUUID()
	uuidStr := newUUID.String()
	uuidStr = regexpNonAlphaNum.ReplaceAllString(uuidStr, "")
	return fmt.Sprintf("%s-%s-%s", sanitizedUsername, sanitizedRepoName, uuidStr)
}

// purgeDevcontainersResource 辅助函数，用于goroutine后台执行，回收DevContainer资源 // TODO
func purgeDevcontainersResource(devcontainersList []devstar_devcontainer_models.DevstarDevcontainer) error {
	for _, devContainer := range devcontainersList {
		log.Info("[Goroutine purgeDevcontainersResource]: 正在装模做样地回收资源： devstar_devcontainer_models.DevstarDevcontainer %v", devContainer)
	}
	return nil
}

// claimDevcontainerResource
func claimDevcontainerResource(newDevContainer *devstar_devcontainer_models.DevstarDevcontainer) error {
	log.Info("[claimDevcontainerResource]: 正在装模做样地分配资源： devstar_devcontainer_models.DevstarDevcontainer %v", newDevContainer)
	return nil
}