// lib/services/projectService.ts
import db from "@/db/db";
import {
  fileSystemProjects,
  fileItems,
  projectMembers,
  fileActivityLogs,
  type FileSystemProject,
  type NewFileSystemProject,
} from "@/db/schema/fileSystem";
import { users } from "@/db/schema/users";
import { eq, and, or, inArray, gte, sql, not } from "drizzle-orm";

// 프로젝트 멤버 역할 타입
export type ProjectRole = "owner" | "admin" | "editor" | "viewer";

export class ProjectService {
  // 프로젝트 생성 (생성자가 자동으로 owner가 됨)
  async createProject(
    data: {
      name: string;
      description?: string;
      isPublic?: boolean;
    },
    userId: number
  ): Promise<FileSystemProject> {
    const [project] = await db.transaction(async (tx) => {
      // 1. 프로젝트 생성
      const [newProject] = await tx
        .insert(fileSystemProjects)
        .values({
          ...data,
          ownerId: userId,
        })
        .returning();

      // 2. 생성자를 owner로 프로젝트 멤버에 추가
      await tx.insert(projectMembers).values({
        projectId: newProject.id,
        userId: userId,
        role: "owner",
        addedBy: userId,
      });

      return [newProject];
    });

    return project;
  }

  // 프로젝트 Owner 확인
  async isProjectOwner(projectId: string, userId: number): Promise<boolean> {
    const project = await db.query.fileSystemProjects.findFirst({
      where: and(
        eq(fileSystemProjects.id, projectId),
        eq(fileSystemProjects.ownerId, userId)
      ),
    });

    return !!project;
  }

  // 프로젝트 접근 권한 확인
  async checkProjectAccess(
    projectId: string,
    userId: number,
    requiredRole?: ProjectRole
  ): Promise<{
    hasAccess: boolean;
    role?: ProjectRole;
    isOwner: boolean;
  }> {
    // 1. Owner 확인
    const project = await db.query.fileSystemProjects.findFirst({
      where: eq(fileSystemProjects.id, projectId),
    });

    if (!project) {
      return { hasAccess: false, isOwner: false };
    }

    const isOwner = project.ownerId === userId;
    
    // Owner는 모든 권한 보유
    if (isOwner) {
      return { hasAccess: true, role: "owner", isOwner: true };
    }

    // 2. 프로젝트 멤버 확인
    const member = await db.query.projectMembers.findFirst({
      where: and(
        eq(projectMembers.projectId, projectId),
        eq(projectMembers.userId, userId)
      ),
    });

    if (!member) {
      // 공개 프로젝트인 경우 viewer 권한
      if (project.isPublic) {
        return { 
          hasAccess: !requiredRole || requiredRole === "viewer",
          role: "viewer",
          isOwner: false 
        };
      }
      return { hasAccess: false, isOwner: false };
    }

    // 3. 역할 계층 확인
    const roleHierarchy: Record<ProjectRole, number> = {
      owner: 4,
      admin: 3,
      editor: 2,
      viewer: 1,
    };

    const hasRequiredRole = !requiredRole || 
      roleHierarchy[member.role] >= roleHierarchy[requiredRole];

    return {
      hasAccess: hasRequiredRole,
      role: member.role as ProjectRole,
      isOwner: false,
    };
  }

  // 프로젝트 멤버 추가 (Owner만 가능)
  async addProjectMember(
    projectId: string,
    newMemberId: number,
    role: ProjectRole,
    addedByUserId: number
  ): Promise<void> {
    // Owner 권한 확인
    const isOwner = await this.isProjectOwner(projectId, addedByUserId);
    
    if (!isOwner) {
      throw new Error("프로젝트 소유자만 멤버를 추가할 수 있습니다");
    }

    // Owner 역할은 양도를 통해서만 가능
    if (role === "owner") {
      throw new Error("Owner 역할은 직접 할당할 수 없습니다. transferOwnership을 사용하세요.");
    }

    await db.insert(projectMembers).values({
      projectId,
      userId: newMemberId,
      role,
      addedBy: addedByUserId,
    });
  }

  // 프로젝트 소유권 이전 (Owner만 가능)
  async transferOwnership(
    projectId: string,
    currentOwnerId: number,
    newOwnerId: number
  ): Promise<void> {
    await db.transaction(async (tx) => {
      // 1. 현재 Owner 확인
      const project = await tx.query.fileSystemProjects.findFirst({
        where: and(
          eq(fileSystemProjects.id, projectId),
          eq(fileSystemProjects.ownerId, currentOwnerId)
        ),
      });

      if (!project) {
        throw new Error("프로젝트 소유자만 소유권을 이전할 수 있습니다");
      }

      // 2. 프로젝트 owner 업데이트
      await tx
        .update(fileSystemProjects)
        .set({ ownerId: newOwnerId })
        .where(eq(fileSystemProjects.id, projectId));

      // 3. 프로젝트 멤버 역할 업데이트
      // 이전 owner를 admin으로 변경
      await tx
        .update(projectMembers)
        .set({ role: "admin" })
        .where(
          and(
            eq(projectMembers.projectId, projectId),
            eq(projectMembers.userId, currentOwnerId)
          )
        );

      // 새 owner를 owner 역할로 설정 (없으면 추가)
      await tx
        .insert(projectMembers)
        .values({
          projectId,
          userId: newOwnerId,
          role: "owner",
          addedBy: currentOwnerId,
        })
        .onConflictDoUpdate({
          target: [projectMembers.projectId, projectMembers.userId],
          set: { role: "owner", updatedAt: new Date() },
        });
    });
  }

  // 프로젝트 삭제 (Owner만 가능)
  async deleteProject(projectId: string, userId: number): Promise<void> {
    const isOwner = await this.isProjectOwner(projectId, userId);
    
    if (!isOwner) {
      throw new Error("프로젝트 소유자만 프로젝트를 삭제할 수 있습니다");
    }

    // 프로젝트 삭제 (cascade로 관련 파일, 멤버 등도 삭제됨)
    await db.delete(fileSystemProjects).where(eq(fileSystemProjects.id, projectId));
  }

  // 프로젝트 설정 변경 (Owner와 Admin만 가능)
  async updateProjectSettings(
    projectId: string,
    userId: number,
    settings: {
      name?: string;
      description?: string;
      isPublic?: boolean;
      externalAccessEnabled?: boolean;
    }
  ): Promise<void> {
    const access = await this.checkProjectAccess(projectId, userId, "admin");
    
    if (!access.hasAccess) {
      throw new Error("프로젝트 설정을 변경할 권한이 없습니다");
    }

    await db
      .update(fileSystemProjects)
      .set({
        ...settings,
        updatedAt: new Date(),
      })
      .where(eq(fileSystemProjects.id, projectId));
  }

  // 사용자의 프로젝트 목록 조회
  async getUserProjects(userId: number): Promise<{
    owned: FileSystemProject[];
    member: Array<FileSystemProject & { role: ProjectRole }>;
    public: FileSystemProject[];
  }> {
    // 1. 소유한 프로젝트
    const ownedProjects = await db.query.fileSystemProjects.findMany({
      where: eq(fileSystemProjects.ownerId, userId),
      orderBy: (fileSystemProjects, { desc }) => [desc(fileSystemProjects.createdAt)],
    });

    // 2. 멤버로 참여한 프로젝트
    const memberProjects = await db
      .select({
        project: fileSystemProjects,
        role: projectMembers.role,
      })
      .from(projectMembers)
      .innerJoin(fileSystemProjects, eq(fileSystemProjects.id, projectMembers.projectId))
      .where(
        and(
          eq(projectMembers.userId, userId),
          // Owner가 아닌 경우만 (중복 방지) - not 사용
          not(eq(fileSystemProjects.ownerId, userId))
        )
      );

    // 3. 공개 프로젝트 (참여하지 않은)
    const memberProjectIds = memberProjects.map(mp => mp.project.id);
    const ownedProjectIds = ownedProjects.map(p => p.id);
    const allUserProjectIds = [...memberProjectIds, ...ownedProjectIds];
    
    let publicProjects;
    if (allUserProjectIds.length > 0) {
      publicProjects = await db.query.fileSystemProjects.findMany({
        where: and(
          eq(fileSystemProjects.isPublic, true),
          not(eq(fileSystemProjects.ownerId, userId)),
          not(inArray(fileSystemProjects.id, allUserProjectIds))
        ),
        orderBy: (fileSystemProjects, { desc }) => [desc(fileSystemProjects.createdAt)],
      });
    } else {
      // 사용자가 참여한 프로젝트가 없는 경우
      publicProjects = await db.query.fileSystemProjects.findMany({
        where: and(
          eq(fileSystemProjects.isPublic, true),
          not(eq(fileSystemProjects.ownerId, userId))
        ),
        orderBy: (fileSystemProjects, { desc }) => [desc(fileSystemProjects.createdAt)],
      });
    }

    return {
      owned: ownedProjects,
      member: memberProjects.map(mp => ({
        ...mp.project,
        role: mp.role as ProjectRole,
      })),
      public: publicProjects,
    };
  }

  // 프로젝트 통계 (Owner용)
  async getProjectStats(projectId: string, userId: number) {
    const isOwner = await this.isProjectOwner(projectId, userId);
    
    if (!isOwner) {
      throw new Error("프로젝트 통계는 소유자만 볼 수 있습니다");
    }

    // 파일 통계
    const fileStats = await db
      .select({
        totalFiles: sql<number>`COUNT(*)`,
        totalSize: sql<number>`COALESCE(SUM(size), 0)`,
        publicFiles: sql<number>`COUNT(CASE WHEN category = 'public' THEN 1 END)`,
        restrictedFiles: sql<number>`COUNT(CASE WHEN category = 'restricted' THEN 1 END)`,
        confidentialFiles: sql<number>`COUNT(CASE WHEN category = 'confidential' THEN 1 END)`,
      })
      .from(fileItems)
      .where(eq(fileItems.projectId, projectId));

    // 멤버 통계
    const memberStats = await db
      .select({
        totalMembers: sql<number>`COUNT(*)`,
        admins: sql<number>`COUNT(CASE WHEN role = 'admin' THEN 1 END)`,
        editors: sql<number>`COUNT(CASE WHEN role = 'editor' THEN 1 END)`,
        viewers: sql<number>`COUNT(CASE WHEN role = 'viewer' THEN 1 END)`,
      })
      .from(projectMembers)
      .where(eq(projectMembers.projectId, projectId));

    // 활동 통계 (최근 30일)
    const activityStats = await db
      .select({
        totalViews: sql<number>`COUNT(CASE WHEN action = 'view' THEN 1 END)`,
        totalDownloads: sql<number>`COUNT(CASE WHEN action = 'download' THEN 1 END)`,
        totalUploads: sql<number>`COUNT(CASE WHEN action = 'upload' THEN 1 END)`,
        uniqueUsers: sql<number>`COUNT(DISTINCT user_id)`,
      })
      .from(fileActivityLogs)
      .where(
        and(
          eq(fileActivityLogs.projectId, projectId),
          gte(fileActivityLogs.createdAt, new Date(Date.now() - 30 * 24 * 60 * 60 * 1000))
        )
      );

    return {
      files: fileStats[0],
      members: memberStats[0],
      activity: activityStats[0],
    };
  }

  // 개별 프로젝트 정보 조회
  async getProject(projectId: string): Promise<FileSystemProject | null> {
    const project = await db.query.fileSystemProjects.findFirst({
      where: eq(fileSystemProjects.id, projectId),
      with: {
        owner: true,
      },
    });

    return project || null;
  }

  // 프로젝트 보관
  async archiveProject(projectId: string, userId: number): Promise<void> {
    const isOwner = await this.isProjectOwner(projectId, userId);
    
    if (!isOwner) {
      throw new Error("프로젝트 소유자만 보관할 수 있습니다");
    }

    // 프로젝트를 보관 상태로 변경
    await db
      .update(fileSystemProjects)
      .set({
        metadata: sql`jsonb_set(metadata, '{archived}', 'true')`,
        updatedAt: new Date(),
      })
      .where(eq(fileSystemProjects.id, projectId));
  }

  // 멤버 역할 업데이트
  async updateMemberRole(
    projectId: string,
    memberId: string,
    newRole: ProjectRole
  ): Promise<void> {
    // Owner 역할은 transferOwnership를 통해서만 가능
    if (newRole === 'owner') {
      throw new Error("Owner 역할은 소유권 이전을 통해서만 가능합니다");
    }

    await db
      .update(projectMembers)
      .set({
        role: newRole,
        updatedAt: new Date(),
      })
      .where(
        and(
          eq(projectMembers.projectId, projectId),
          eq(projectMembers.id, memberId)
        )
      );
  }

  // 프로젝트 멤버 제거
  async removeMember(projectId: string, memberId: string): Promise<void> {
    // Owner는 제거할 수 없음
    const member = await db.query.projectMembers.findFirst({
      where: and(
        eq(projectMembers.projectId, projectId),
        eq(projectMembers.id, memberId)
      ),
    });

    if (member?.role === 'owner') {
      throw new Error("Owner는 제거할 수 없습니다");
    }

    await db
      .delete(projectMembers)
      .where(
        and(
          eq(projectMembers.projectId, projectId),
          eq(projectMembers.id, memberId)
        )
      );
  }

  // 프로젝트 멤버 목록 조회
  async getProjectMembers(projectId: string): Promise<any[]> {
    const members = await db
      .select({
        id: projectMembers.id,
        userId: projectMembers.userId,
        role: projectMembers.role,
        addedAt: projectMembers.createdAt,
        user: {
          name: users.name,
          email: users.email,
          imageUrl: users.imageUrl,
          domain: users.domain,
        },
      })
      .from(projectMembers)
      .innerJoin(users, eq(users.id, projectMembers.userId))
      .where(eq(projectMembers.projectId, projectId))
      .orderBy(
        sql`CASE 
          WHEN ${projectMembers.role} = 'owner' THEN 1
          WHEN ${projectMembers.role} = 'admin' THEN 2
          WHEN ${projectMembers.role} = 'editor' THEN 3
          ELSE 4
        END`
      );

    return members;
  }
}