pub struct AbsenceImpact {
  worker_id : String
  baseline_feasible : Bool
  absence_feasible : Bool
  baseline_score : Int
  absence_score : Int
  score_increase : Int
  baseline_coverage : Int
  absence_coverage : Int
  coverage_loss : Int
  newly_critical_shifts : Int
  severity : RiskLevel
} derive(Eq, Show, ToJson)

pub struct Assignment {
  worker_id : String
  shift_id : String
  locked : Bool
} derive(Eq, Show, ToJson)

pub struct AuditEvent {
  sequence : Int
  kind : AuditEventKind
  message : String
  worker_id : String?
  shift_id : String?
  score_before : Int?
  score_after : Int?
} derive(Eq, Show, ToJson)

pub(all) enum AuditEventKind {
  ProblemValidated
  CandidateConsidered
  CandidateRejected
  AssignmentAdded
  AssignmentMoved
  ImprovementAccepted
  CoverageChecked
  SolutionCompleted
} derive(Eq, Show, ToJson)

pub struct AuditTrail {
  events : Array[AuditEvent]
} derive(Eq, Show, ToJson)

pub struct AuditedSolution {
  solution : Solution
  audit : AuditTrail
} derive(Eq, Show, ToJson)

pub struct Candidate {
  worker_id : String
  shift_id : String
  delta : Int
  tie_breaker : Int
} derive(Eq, Show, ToJson)

pub struct CapacityRecommendation {
  code : String
  title : String
  detail : String
  priority : Int
  worker_id : String?
  shift_id : String?
  skill_id : String?
} derive(Eq, Show, ToJson)

pub struct CapacityReport {
  shifts : Array[ShiftCapacity]
  skills : Array[SkillCapacity]
  critical_shifts : Int
  critical_skills : Int
  total_required_slots : Int
  total_eligible_instances : Int
  resilience_score : Int
} derive(Eq, Show, ToJson)

pub struct ConstraintReport {
  violations : Array[ConstraintViolation]
  hard_count : Int
  soft_count : Int
} derive(Eq, Show, ToJson)

pub struct ConstraintViolation {
  kind : ViolationKind
  message : String
  worker_id : String?
  shift_id : String?
  hard : Bool
  magnitude : Int
} derive(Eq, Show, ToJson)

pub struct CsvIssue {
  source : String
  line : Int
  column : Int
  code : String
  message : String
} derive(Eq, Show, ToJson)

type DeterministicRandom

pub struct Diagnostic {
  code : String
  severity : DiagnosticSeverity
  message : String
  worker_id : String?
  shift_id : String?
} derive(Eq, Show, ToJson)

pub(all) enum DiagnosticSeverity {
  Info
  Warning
  Error
} derive(Eq, Show, ToJson)

pub struct Explanation {
  kind : ExplanationKind
  title : String
  detail : String
  worker_id : String?
  shift_id : String?
  priority : Int
} derive(Eq, Show, ToJson)

pub(all) enum ExplanationKind {
  AssignmentAccepted
  AssignmentRejected
  CoverageFailure
  SkillCoverageFailure
  WorkloadObservation
  PreferenceObservation
  ImprovementSuggestion
} derive(Eq, Show, ToJson)

pub struct FairnessWeights {
  workload : Int
  night : Int
  weekend : Int
  preference : Int
  understaffing : Int
  overtime : Int
} derive(Eq, Show, ToJson)

pub struct Minute {
  value_ : Int
} derive(Compare, Eq, Show, ToJson)

pub struct PlanningProblem {
  name : String
  workers : Array[Worker]
  skills : Array[Skill]
  shifts : Array[Shift]
  locked_assignments : Array[Assignment]
  weights : FairnessWeights
  seed : Int
} derive(Eq, Show, ToJson)

pub(all) enum PreferenceKind {
  Prefer
  Avoid
  Require
  Unavailable
} derive(Eq, Show, ToJson)

pub(all) enum ProblemParseResult {
  Parsed(PlanningProblem)
  ParseFailed(Array[CsvIssue])
} derive(Eq, Show, ToJson)

pub(all) enum RiskLevel {
  LowRisk
  ModerateRisk
  HighRisk
  CriticalRisk
} derive(Compare, Eq, Show, ToJson)

pub struct Schedule {
  assignments : Array[Assignment]
} derive(Eq, Show, ToJson)

pub struct ScheduleSummary {
  problem_name : String
  worker_count : Int
  shift_count : Int
  assignment_count : Int
  coverage_per_mille : Int
  workload_spread : Int
  night_spread : Int
  weekend_spread : Int
  feasible : Bool
  score : ScoreBreakdown
  workers : Array[WorkerSummary]
  shifts : Array[ShiftSummary]
} derive(Eq, Show, ToJson)

pub struct ScoreBreakdown {
  total : Int
  understaffing : Int
  skill_shortage : Int
  workload_imbalance : Int
  night_imbalance : Int
  weekend_imbalance : Int
  preference_cost : Int
  overtime_cost : Int
} derive(Eq, Show, ToJson)

pub struct SensitivityReport {
  impacts : Array[AbsenceImpact]
  critical_workers : Array[String]
  high_risk_workers : Array[String]
  most_critical_worker : String?
  worst_coverage_loss : Int
  worst_score_increase : Int
} derive(Eq, Show, ToJson)

pub struct Shift {
  id : String
  label : String
  range : TimeRange
  kind : ShiftKind
  required_workers : Int
  preferred_workers : Int
  requirements : Array[SkillRequirement]
  tags : Array[String]
  day_index : Int
  weekend : Bool
} derive(Eq, Show, ToJson)

pub struct ShiftCapacity {
  shift_id : String
  required_workers : Int
  available_workers : Int
  eligible_workers : Int
  capacity_margin : Int
  risk : RiskLevel
} derive(Eq, Show, ToJson)

pub(all) enum ShiftKind {
  Morning
  Day
  Evening
  Night
  OnCall
  Custom(String)
} derive(Eq, Show, ToJson)

pub struct ShiftPreference {
  shift_id : String
  kind : PreferenceKind
  weight : Int
} derive(Eq, Show, ToJson)

pub struct ShiftSummary {
  shift_id : String
  label : String
  assigned : Int
  required : Int
  qualified_requirements : Int
  total_requirements : Int
  covered : Bool
} derive(Eq, Show, ToJson)

pub struct Skill {
  id : String
  name : String
} derive(Eq, Show, ToJson)

pub struct SkillCapacity {
  skill_id : String
  required_slots : Int
  qualified_workers : Int
  qualification_instances : Int
  margin : Int
  risk : RiskLevel
} derive(Eq, Show, ToJson)

pub(all) enum SkillLevel {
  Beginner
  Qualified
  Advanced
  Expert
} derive(Compare, Eq, Show, ToJson)

pub struct SkillRequirement {
  skill_id : String
  minimum_level : SkillLevel
  count : Int
} derive(Eq, Show, ToJson)

pub struct Solution {
  schedule : Schedule
  score : ScoreBreakdown
  diagnostics : Array[Diagnostic]
  feasible : Bool
  stats : SolveStats
} derive(Eq, Show, ToJson)

pub struct SolutionComparison {
  left_score : Int
  right_score : Int
  score_delta : Int
  left_coverage : Int
  right_coverage : Int
  coverage_delta : Int
  left_workload_spread : Int
  right_workload_spread : Int
  workload_spread_delta : Int
  changed_assignments : Int
  recommendation : String
} derive(Eq, Show, ToJson)

pub struct SolveStats {
  explored_nodes : Int
  pruned_nodes : Int
  improvements : Int
  elapsed_steps : Int
} derive(Eq, Show, ToJson)

pub struct SolverConfig {
  max_iterations : Int
  candidate_limit : Int
  allow_partial : Bool
  improve : Bool
  seed : Int
} derive(Eq, Show, ToJson)

pub struct TimeRange {
  start : Minute
  end : Minute
} derive(Eq, Show, ToJson)

pub(all) enum ViolationKind {
  UnknownWorker
  UnknownShift
  DuplicateAssignment
  WorkerUnavailable
  ExplicitlyUnavailable
  MissingRequiredPreference
  OverlappingShift
  InsufficientRest
  WeeklyMinuteLimit
  ConsecutiveShiftLimit
  MissingSkill
  Understaffed
  SkillShortage
} derive(Eq, Show, ToJson)

pub struct Worker {
  id : String
  name : String
  skills : Array[WorkerSkill]
  availability : Array[TimeRange]
  preferences : Array[ShiftPreference]
  min_minutes : Int
  target_minutes : Int
  max_minutes : Int
  max_consecutive_shifts : Int
  min_rest_minutes : Int
} derive(Eq, Show, ToJson)

pub struct WorkerSkill {
  skill_id : String
  level : SkillLevel
} derive(Eq, Show, ToJson)

pub struct WorkerSummary {
  worker_id : String
  assigned_minutes : Int
  target_minutes : Int
  night_shifts : Int
  weekend_shifts : Int
  preference_cost : Int
} derive(Eq, Show, ToJson)

fn analyze_absence(problem : PlanningProblem, worker_id : String, config : SolverConfig) -> AbsenceImpact?

fn analyze_capacity(problem : PlanningProblem) -> CapacityReport

fn analyze_sensitivity(problem : PlanningProblem, config : SolverConfig) -> SensitivityReport

fn assignment_count_for_shift(schedule : Schedule, shift_id : String) -> Int

fn assignment_delta(problem : PlanningProblem, schedule : Schedule, worker_id : String, shift_id : String) -> Int

fn capacity_recommendations(problem : PlanningProblem, capacity : CapacityReport, sensitivity : SensitivityReport) -> Array[CapacityRecommendation]

fn check_candidate(problem : PlanningProblem, schedule : Schedule, worker_id : String, shift_id : String) -> ConstraintReport

fn clinic_scenario() -> PlanningProblem