import 'reflect-metadata';
import {Expose, Transform, Type} from 'class-transformer';
import {JSONSchema} from 'class-validator-jsonschema';
import {
  IsNotEmpty,
  IsString,
  IsBoolean,
  IsNumber,
  IsOptional,
  IsMongoId,
  IsEnum,
  ValidateNested,
  IsObject,
  Min,
  IsArray,
  IsDate,
  IsInt,
  Max,
  ValidateIf,
  ArrayMinSize,
} from 'class-validator';
import {
  InactivityTrigger,
  MissedDeadlinesTrigger,
  PolicyViolationsTrigger,
  CustomTrigger,
} from '../../types.js';

// ============ Trigger Classes ============

export class InactivityTriggerDto implements InactivityTrigger {
  @Expose()
  @IsBoolean()
  enabled: boolean;

  @Expose()
  @IsNumber()
  @Min(1)
  thresholdDays: number;

  @Expose()
  @IsNumber()
  @Min(0)
  warningDays: number;
}

export class MissedDeadlinesTriggerDto implements MissedDeadlinesTrigger {
  @IsBoolean()
  @Expose()
  enabled: boolean;

  @IsNumber()
  @Expose()
  @Min(1)
  consecutiveMisses: number;

  @IsNumber()
  @Expose()
  @Min(0)
  warningAfterMisses: number;

  @ValidateIf(o => o.enabled)
  @ArrayMinSize(1, { message: 'At least one progress rule is required when missed deadlines trigger is enabled' })
  @IsArray()
  @ValidateNested({each: true})
  @Type(() => ProgressRuleDto)
  @Expose()
  progressRules?: ProgressRuleDto[];
}

export class ProgressRuleDto {
  @IsNumber()
  @Expose()
  @Min(1)
  timeframeDays: number;

  @IsNumber()
  @Expose()
  @Min(0)
  @Max(100)
  targetPercentage: number;
}

@Expose()
export class ViolationsDto {
  @IsArray()
  @IsString({each: true})
  @Expose()
  predefined: string[];

  @IsOptional()
  @IsArray()
  @IsString({each: true})
  @Expose()
  custom?: string[];
}

export class PolicyViolationsTriggerDto {
  @IsBoolean()
  @Expose()
  enabled: boolean;

  @ValidateNested()
  @Type(() => ViolationsDto)
  @Expose()
  violations: ViolationsDto;

  @IsNumber()
  @Expose()
  @Min(1)
  thresholdCount: number;
}

export class CustomTriggerDto implements CustomTrigger {
  @IsString()
  @Expose()
  type: string;

  @IsObject()
  @Expose()
  condition: Record<string, any>;

  @IsNumber()
  @Expose()
  threshold: number;
}
export class AnomalyDetectionTriggerDto {
  @IsBoolean()
  @Expose()
  enabled: boolean;

  @IsNumber()
  @Expose()
  @Min(0)
  thresholdScore: number;

  @IsOptional()
  @IsNumber()
  @Expose()
  @Min(0)
  warningScore?: number;
}

export class PolicyTriggersDto {
  @IsOptional()
  @ValidateNested()
  @Type(() => InactivityTriggerDto)
  @Expose()
  inactivity?: InactivityTriggerDto;

  @IsOptional()
  @ValidateNested()
  @Type(() => MissedDeadlinesTriggerDto)
  @Expose()
  missedDeadlines?: MissedDeadlinesTriggerDto;

  @IsOptional()
  @ValidateNested()
  @Type(() => PolicyViolationsTriggerDto)
  @Expose()
  policyViolations?: PolicyViolationsTriggerDto;

  @IsOptional()
  @ValidateNested()
  @Type(() => AnomalyDetectionTriggerDto)
  @Expose()
  anomalyDetection?: AnomalyDetectionTriggerDto;

  @IsOptional()
  @IsArray()
  @ValidateNested({each: true})
  @Type(() => CustomTriggerDto)
  @Expose()
  customTriggers?: CustomTriggerDto[];
}

export class PolicyActionsDto {
  @IsBoolean()
  @Expose()
  sendWarning: boolean;

  @IsOptional()
  @IsString()
  @Expose()
  warningTemplate?: string;

  @IsOptional()
  @IsString()
  @Expose()
  ejectionTemplate?: string;

  @IsBoolean()
  @Expose()
  allowAppeal: boolean;

  @IsOptional()
  @IsNumber()
  @Min(1)
  @Expose()
  appealDeadlineDays?: number;

  @IsOptional()
  @IsObject()
  @Expose()
  autoReinstatementRules?: Record<string, any>;
}

// ============ Request DTOs ============

export class CreateEjectionPolicyBody {
  @JSONSchema({
    description: 'Policy name',
    example: 'Standard Inactivity Policy',
  })
  @IsNotEmpty()
  @IsString()
  name: string;

  @JSONSchema({
    description: 'Policy description',
  })
  @IsOptional()
  @IsString()
  description?: string;

  @JSONSchema({
    description: 'Course ID (required if scope is "course")',
  })
  @IsOptional()
  @IsMongoId()
  courseId?: string;

  @JSONSchema({
    description: 'Course Version ID (required if scope is "course")',
  })
  @IsOptional()
  @IsMongoId()
  courseVersionId?: string;

  @JSONSchema({
    description: 'Cohort ID (required for course-specific policies)',
  })
  @IsNotEmpty()
  @IsMongoId()
  cohortId: string;

  @JSONSchema({
    description: 'Trigger configuration',
  })
  @IsNotEmpty()
  @ValidateNested()
  @Type(() => PolicyTriggersDto)
  triggers: PolicyTriggersDto;

  @JSONSchema({
    description: 'Action configuration',
  })
  @IsNotEmpty()
  @ValidateNested()
  @Type(() => PolicyActionsDto)
  actions: PolicyActionsDto;
}

export class UpdateEjectionPolicyBody {
  @IsOptional()
  @IsString()
  name?: string;

  @IsOptional()
  @IsString()
  description?: string;

  @IsOptional()
  @IsBoolean()
  isActive?: boolean;

  @IsOptional()
  @ValidateNested()
  @Type(() => PolicyTriggersDto)
  triggers?: PolicyTriggersDto;

  @IsOptional()
  @ValidateNested()
  @Type(() => PolicyActionsDto)
  actions?: PolicyActionsDto;
}

// ============ Params ============

export class PolicyIdParams {
  @JSONSchema({
    description: 'Policy ID',
  })
  @IsMongoId()
  @IsNotEmpty()
  policyId: string;
}

export class CourseIdParams {
  @JSONSchema({
    description: 'Course ID',
  })
  @IsMongoId()
  @IsNotEmpty()
  courseId: string;
}

export class CourseVersionParams {
  @JSONSchema({
    description: 'Course ID',
  })
  @IsMongoId()
  @IsNotEmpty()
  courseId: string;

  @JSONSchema({
    description: 'Course Version ID',
  })
  @IsMongoId()
  @IsNotEmpty()
  courseVersionId: string;
}

// ============ Query Params ============

export class GetPoliciesQuery {
  @IsOptional()
  @IsMongoId()
  courseId?: string;

  @IsOptional()
  @IsMongoId()
  courseVersionId?: string;

  @IsOptional()
  @IsMongoId()
  @JSONSchema({type: 'string', description: 'Cohort ID filter'})
  cohortId?: string;

  @IsOptional()
  @IsBoolean()
  @Type(() => Boolean)
  active?: boolean;
}

@Expose()
export class EjectionPolicyResponse {
  @IsString()
  @Expose()
  @Transform(({value}) => value?.toString())
  @JSONSchema({
    description: 'Policy ID',
    example: '507f1f77bcf86cd799439011',
  })
  _id: string;

  @IsString()
  @Expose()
  @JSONSchema({
    description: 'Policy name',
    example: 'Platform Inactivity Policy',
  })
  name: string;

  @IsString()
  @IsOptional()
  @Expose()
  @JSONSchema({
    description: 'Policy description',
    example: 'Removes inactive users after 30 days',
  })
  description?: string;

  @IsString()
  @IsOptional()
  @Expose()
  @Transform(({value}) => value?.toString())
  @JSONSchema({
    description: 'Course ID (for course-specific policies)',
    example: '507f1f77bcf86cd799439011',
  })
  courseId?: string;

  @IsString()
  @IsOptional()
  @Expose()
  @Transform(({value}) => value?.toString())
  @JSONSchema({
    description: 'Course Version ID (for course-specific policies)',
    example: '507f1f77bcf86cd799439011',
  })
  courseVersionId?: string;

  @IsString()
  @IsOptional()
  @Expose()
  @Transform(({value}) => value?.toString())
  @JSONSchema({
    description: 'Cohort ID this policy applies to',
    example: '507f1f77bcf86cd799439011',
  })
  cohortId?: string;

  @IsBoolean()
  @Expose()
  @JSONSchema({
    description: 'Whether the policy is active',
    example: true,
  })
  isActive: boolean;

  @ValidateNested()
  @Type(() => PolicyTriggersDto)
  @Expose()
  @JSONSchema({
    description: 'Policy triggers',
  })
  triggers: PolicyTriggersDto;

  @ValidateNested()
  @Type(() => PolicyActionsDto)
  @Expose()
  @JSONSchema({
    description: 'Policy actions',
  })
  actions: PolicyActionsDto;

  @IsString()
  @Expose()
  @Transform(({value}) => value?.toString())
  @JSONSchema({
    description: 'User ID who created the policy',
    example: '507f1f77bcf86cd799439011',
  })
  createdBy: string;

  @IsDate()
  @Type(() => Date)
  @Expose()
  @JSONSchema({
    description: 'Creation timestamp',
    example: '2026-03-14T08:00:00.000Z',
  })
  createdAt: Date;

  @IsDate()
  @Type(() => Date)
  @Expose()
  @JSONSchema({
    description: 'Last update timestamp',
    example: '2026-03-14T08:00:00.000Z',
  })
  updatedAt: Date;

  @IsDate()
  @IsOptional()
  @Type(() => Date)
  @Expose()
  @JSONSchema({
    description: 'Deletion timestamp (if soft deleted)',
  })
  deletedAt?: Date;
}

@Expose()
export class PoliciesListResponse {
  @IsArray()
  @Expose()
  @ValidateNested({each: true})
  @Type(() => EjectionPolicyResponse)
  @JSONSchema({
    description: 'List of ejection policies',
  })
  policies: EjectionPolicyResponse[];

  @IsNumber()
  @Expose()
  @JSONSchema({
    description: 'Total number of policies',
  })
  total: number;

  @IsBoolean()
  @Expose()
  @JSONSchema({
    description: 'Tells if user is an admin',
  })
  isAdmin: boolean;
}

@Expose()
export class DeletePolicyResponse {
  @IsString()
  @Expose()
  @JSONSchema({
    description: 'Success message',
    example: 'Policy deleted successfully',
  })
  message: string;

  @IsString()
  @Expose()
  @JSONSchema({
    description: 'ID of the deleted policy',
    example: '507f1f77bcf86cd799439011',
  })
  policyId: string;
}
// ─── Params ───────────────────────────────────────────────────────────────────

export class EjectionStudentsParams {
  @IsMongoId()
  @IsNotEmpty()
  @JSONSchema({description: 'Course ID'})
  courseId: string;

  @IsMongoId()
  @IsNotEmpty()
  @JSONSchema({description: 'Course Version ID'})
  courseVersionId: string;

  @IsMongoId()
  @IsNotEmpty()
  @JSONSchema({description: 'Cohort ID'})
  cohortId: string;
}

// ─── Query ────────────────────────────────────────────────────────────────────

export class EjectionStudentsQuery {
  @IsOptional()
  @Type(() => Number)
  @IsInt()
  @Min(1)
  @JSONSchema({type: 'integer', minimum: 1})
  page: number = 1;

  @IsOptional()
  @Type(() => Number)
  @IsInt()
  @Min(1)
  @JSONSchema({type: 'integer', minimum: 1})
  limit: number = 20;

  @IsOptional()
  @IsString()
  @JSONSchema({type: 'string', description: 'Search by name or email'})
  search?: string;

  @IsOptional()
  @IsString()
  @JSONSchema({type: 'string', description: 'Filter by status'})
  statusFilter?: 'all' | 'active' | 'ejected' = 'all';
}

// ─── Response ─────────────────────────────────────────────────────────────────

@Expose()
export class StudentEjectionHistoryEntry {
  @IsDate()
  @Type(() => Date)
  @Expose()
  ejectedAt: Date;

  @IsString()
  @Expose()
  ejectionReason: string;

  @IsString()
  @Expose()
  @Transform(({value}) => value?.toString())
  ejectedBy: string;

  @IsOptional()
  @IsString()
  @Expose()
  @JSONSchema({description: 'Display name of the user who ejected the learner'})
  ejectedByName?: string;

  @IsOptional()
  @IsString()
  @Expose()
  @Transform(({value}) => value?.toString())
  policyId?: string;

  @IsOptional()
  @IsDate()
  @Type(() => Date)
  @Expose()
  reinstatedAt?: Date;

  @IsOptional()
  @IsString()
  @Expose()
  @Transform(({value}) => value?.toString())
  reinstatedBy?: string;
}

@Expose()
export class EjectionStudentResponse {
  @IsString()
  @Expose()
  @Transform(({value}) => value?.toString())
  @JSONSchema({description: 'Enrollment ID'})
  enrollmentId: string;

  @IsString()
  @Expose()
  @Transform(({value}) => value?.toString())
  @JSONSchema({description: 'User ID'})
  userId: string;

  @IsString()
  @Expose()
  @JSONSchema({description: 'Full name'})
  name: string;

  @IsString()
  @Expose()
  @JSONSchema({description: 'Email'})
  email: string;

  @IsDate()
  @Type(() => Date)
  @Expose()
  @JSONSchema({description: 'Enrollment date'})
  enrollmentDate: Date;

  @IsNumber()
  @Expose()
  @JSONSchema({description: 'Course completion percentage'})
  percentCompleted: number;

  @IsBoolean()
  @Expose()
  @JSONSchema({description: 'Whether the student is currently ejected'})
  isEjected: boolean;

  @IsString()
  @Expose()
  @JSONSchema({
    description: 'Status: active | ejected | warning',
    enum: ['active', 'ejected', 'warning'],
  })
  ejectionStatus: 'active' | 'ejected' | 'warning';

  @IsOptional()
  @IsDate()
  @Type(() => Date)
  @Expose()
  @JSONSchema({description: 'Last time the student was active in the course'})
  lastActiveAt?: Date;

  @IsOptional()
  @IsInt()
  @Expose()
  @JSONSchema({
    description:
      'Days since last activity — used for inactivity trigger preview',
  })
  daysSinceLastActive?: number;

  @IsArray()
  @ValidateNested({each: true})
  @Type(() => StudentEjectionHistoryEntry)
  @Expose()
  @JSONSchema({description: 'Full ejection history for this student'})
  ejectionHistory: StudentEjectionHistoryEntry[];
}

@Expose()
export class EjectionStudentsListResponse {
  @IsArray()
  @ValidateNested({each: true})
  @Type(() => EjectionStudentResponse)
  @Expose()
  students: EjectionStudentResponse[];

  @IsArray()
  @ValidateNested({each: true})
  @Type(() => EjectionPolicyResponse)
  @Expose()
  @IsOptional()
  policies: EjectionPolicyResponse[];

  @IsInt()
  @Expose()
  totalDocuments: number;

  @IsInt()
  @Expose()
  totalPages: number;

  @IsInt()
  @Expose()
  currentPage: number;
}