package main

import (
	"fmt"
	"os"

	"git.cin.su/m/Assistant/contracts/capability"
	"git.cin.su/m/Assistant/contracts/identity"
)

// candidateReleaseContextFromRuntime accepts only deployment-owned metadata.
// It never derives a candidate slot from an HTTP request or notification body.
func candidateReleaseContextFromRuntime() (*capability.CandidateReleaseContext, error) {
	const prefix = "CANDIDATE_"
	release := os.Getenv(prefix + "RELEASE_SET_ID")
	if release == "" {
		return nil, nil
	}
	context := &capability.CandidateReleaseContext{
		ReleaseSetID:     release,
		Slot:             os.Getenv(prefix + "SLOT"),
		TaskID:           os.Getenv(prefix + "TASK_ID"),
		PrincipalID:      identity.PrincipalID(os.Getenv(prefix + "PRINCIPAL_ID")),
		CapabilityID:     capability.CapabilityID(os.Getenv(prefix + "CAPABILITY_ID")),
		ResourceScope:    os.Getenv(prefix + "RESOURCE_SCOPE"),
		Mode:             capability.CandidateBindingMode(os.Getenv(prefix + "BINDING_MODE")),
		TargetKind:       os.Getenv(prefix + "TARGET_KIND"),
		TargetRef:        os.Getenv(prefix + "TARGET_REF"),
		TargetDigest:     os.Getenv(prefix + "TARGET_DIGEST"),
		AuthorityGrantID: os.Getenv(prefix + "AUTHORITY_GRANT_ID"),
	}
	var revision int64
	if _, err := fmt.Sscan(os.Getenv(prefix+"TASK_REVISION"), &revision); err != nil {
		return nil, fmt.Errorf("candidate task revision: %w", err)
	}
	context.TaskRevision = revision
	if context.Slot == "" || context.TaskID == "" || context.TaskRevision < 1 || context.PrincipalID == "" || context.CapabilityID == "" || context.ResourceScope == "" || context.Mode == "" || context.TargetKind == "" || context.TargetRef == "" || context.TargetDigest == "" || context.AuthorityGrantID == "" {
		return nil, fmt.Errorf("incomplete candidate release metadata")
	}
	return context, nil
}