package domain

import (
	"errors"
	"slices"

	"git.cin.su/m/Assistant/contracts/work"
)

var ErrInvalidDevelopmentGate = errors.New("invalid governed self-development gate")

func AdvanceDevelopmentGate(current work.DevelopmentGate, next work.DevelopmentStage) (work.DevelopmentGate, error) {
	if err := ValidateDevelopmentGate(current); err != nil {
		return work.DevelopmentGate{}, err
	}
	if !validDevelopmentTransition(current.Stage, next) {
		return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
	}
	current.Stage = next
	switch next {
	case work.DevelopmentProposalCreated:
		if current.ProposalRef == "" {
			return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
		}
	case work.DevelopmentTaskAdmitted:
		if current.TaskPacketRef == "" {
			return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
		}
	case work.DevelopmentIsolated:
		if current.WorktreeRef == "" {
			return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
		}
	case work.DevelopmentVerified:
		if current.VerificationEvidence == "" || len(current.VerifierRunRefs) == 0 || len(current.ProducerRunRefs) == 0 || sameRuns(current.ProducerRunRefs, current.VerifierRunRefs) {
			return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
		}
	case work.DevelopmentCanary:
		if current.CanaryEvidence == "" {
			return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
		}
	case work.DevelopmentPromoted:
		if current.PromotionRef == "" {
			return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
		}
	case work.DevelopmentRolledBack:
		if current.RollbackRef == "" {
			return work.DevelopmentGate{}, ErrInvalidDevelopmentGate
		}
	}
	return current, nil
}

func ValidateDevelopmentGate(value work.DevelopmentGate) error {
	if value.ID == "" || len(value.EvidenceRefs) == 0 || !validDevelopmentStage(value.Stage) || duplicateStrings(value.EvidenceRefs) {
		return ErrInvalidDevelopmentGate
	}
	return nil
}

func validDevelopmentTransition(current, next work.DevelopmentStage) bool {
	if current == work.DevelopmentCanary && next == work.DevelopmentRolledBack {
		return true
	}
	if current == work.DevelopmentPromoted || current == work.DevelopmentRolledBack {
		return false
	}
	order := []work.DevelopmentStage{work.DevelopmentEvidenceCollected, work.DevelopmentProposalCreated, work.DevelopmentTaskAdmitted, work.DevelopmentIsolated, work.DevelopmentVerified, work.DevelopmentCanary, work.DevelopmentPromoted}
	index := func(value work.DevelopmentStage) int { return slices.Index(order, value) }
	return index(next) == index(current)+1
}

func validDevelopmentStage(value work.DevelopmentStage) bool {
	return slices.Contains([]work.DevelopmentStage{work.DevelopmentEvidenceCollected, work.DevelopmentProposalCreated, work.DevelopmentTaskAdmitted, work.DevelopmentIsolated, work.DevelopmentVerified, work.DevelopmentCanary, work.DevelopmentPromoted, work.DevelopmentRolledBack}, value)
}

func duplicateStrings(values []string) bool {
	seen := map[string]bool{}
	for _, value := range values {
		if value == "" || seen[value] {
			return true
		}
		seen[value] = true
	}
	return false
}

func sameRuns(left, right []work.AgentRunID) bool {
	if len(left) != len(right) {
		return false
	}
	for _, value := range left {
		if !slices.Contains(right, value) {
			return false
		}
	}
	return true
}