// Package aioemodule is the HTTP surface of the Adaptive Intelligence Optimization Engine: outcome
// capture from every module, and the admin status and audit trail reads. The engine itself (the
// batch updater) lives in internal/aioe and never runs on a request path.
package aioemodule

import (
	"encoding/json"
	"time"

	"github.com/google/uuid"
	"github.com/shopspring/decimal"
)

// validModules and validEventTypes mirror the CHECK constraints on outcome_events exactly, so a bad
// payload fails fast with a clear 400 instead of a database error.
var validModules = map[string]bool{"screen": true, "match": true, "slate": true, "command": true}

var validEventTypes = map[string]bool{
	"screening_decision": true, "interview_result": true, "offer_result": true,
	"placement_result": true, "slate_result": true, "match_feedback": true,
}

// PostOutcomeRequest records one outcome event. SignalValue is a json number or numeric string in
// [-1, 1] (for example advance 1, hold 0, reject -1). RequirementID is optional; when present with
// a candidate subject the service denormalizes the served per dimension scores into the event
// metadata so the batch updater can consume outcome_events alone.
type PostOutcomeRequest struct {
	Module        string          `json:"module"`
	SubjectType   string          `json:"subjectType"`
	SubjectID     uuid.UUID       `json:"subjectId"`
	RequirementID *uuid.UUID      `json:"requirementId,omitempty"`
	EventType     string          `json:"eventType"`
	SignalValue   json.Number     `json:"signalValue"`
	ReasonCode    string          `json:"reasonCode"`
	OccurredAt    *time.Time      `json:"occurredAt,omitempty"`
	Metadata      json.RawMessage `json:"metadata,omitempty"`
}

// PostOutcomeResponse acknowledges the recorded event.
type PostOutcomeResponse struct {
	ID         uuid.UUID `json:"id"`
	OccurredAt time.Time `json:"occurredAt"`
}

// StatusResponse is the admin proof of life: how many outcomes the org has recorded, the last
// engine run, the active profile, and this month's adjustment count.
type StatusResponse struct {
	OutcomesRecorded     int64      `json:"outcomesRecorded"`
	LastRunAt            *time.Time `json:"lastRunAt,omitempty"`
	LastRunOutcomesSeen  *int       `json:"lastRunOutcomesSeen,omitempty"`
	LastRunProfilesMoved *int       `json:"lastRunProfilesMoved,omitempty"`
	ActiveProfileVersion string     `json:"activeProfileVersion"`
	AdjustmentsThisMonth int64      `json:"adjustmentsThisMonth"`
	UpdaterConfigured    bool       `json:"updaterConfigured"`
	// ShadowMode is true when the updater proposes candidate profiles a human must promote rather
	// than activating them automatically.
	ShadowMode bool `json:"shadowMode"`
	// PendingCandidateVersion is the profile version of a candidate awaiting promotion, or empty.
	PendingCandidateVersion string `json:"pendingCandidateVersion,omitempty"`
}

// AdjustmentView is one audit trail row for the admin history endpoint.
type AdjustmentView struct {
	Dimension       string    `json:"dimension"`
	OldValue        string    `json:"oldValue"`
	NewValue        string    `json:"newValue"`
	ProducedVersion int       `json:"producedVersion"`
	WindowStart     time.Time `json:"windowStart"`
	WindowEnd       time.Time `json:"windowEnd"`
	OutcomesUsed    int       `json:"outcomesUsed"`
	Rationale       string    `json:"rationale"`
	CreatedAt       time.Time `json:"createdAt"`
}

// parseSignal validates the signal into a decimal in [-1, 1].
func parseSignal(n json.Number) (decimal.Decimal, bool) {
	d, err := decimal.NewFromString(n.String())
	if err != nil {
		return decimal.Zero, false
	}
	one := decimal.NewFromInt(1)
	if d.GreaterThan(one) || d.LessThan(one.Neg()) {
		return decimal.Zero, false
	}
	return d, true
}