package contract

import (
	"fmt"
	"strings"

	"git.ipao.vip/rogee/go-sip/contracts"
	"github.com/santhosh-tekuri/jsonschema/v6"
	"github.com/santhosh-tekuri/jsonschema/v6/kind"
)

// ValidationFailure retains original bytes for private evidence, never Error/log output.
type ValidationFailure struct {
	Surface  string
	Resource string
	Raw      []byte
	Reason   string
}

func (e *ValidationFailure) Error() string { return e.Surface + " validation failed: " + e.Reason }

func newValidationFailure(surface string, raw []byte, value any, cause error) error {
	// Discriminate the MQ branch only to explain an already proven validation failure.
	// This does not broaden acceptance or replace validation of the complete union.
	if surface == "mq" {
		if m, ok := value.(map[string]any); ok {
			p, _ := m["payload"].(map[string]any)
			if _, receipt := p["status"]; !receipt {
				names := map[string]string{"task.control": "mq-task-control-request.schema.json", "call.execute": "mq-call-execute-request.schema.json", "sip.config": "mq-sip-config.schema.json"}
				if name := names[fmt.Sprint(m["event_type"])]; name != "" {
					if s, err := contracts.CompileCurrent(name); err == nil {
						if detail := s.Validate(value); detail != nil {
							cause = detail
						}
					}
				}
			}
		}
	}
	var details []string
	var walk func(*jsonschema.ValidationError)
	walk = func(e *jsonschema.ValidationError) {
		if len(details) >= 32 {
			return
		}
		if len(e.Causes) > 0 {
			for _, c := range e.Causes {
				walk(c)
			}
			return
		}
		path := "/" + strings.Join(e.InstanceLocation, "/")
		if r, ok := e.ErrorKind.(*kind.Required); ok {
			for _, k := range r.Missing {
				details = append(details, strings.TrimSuffix(path, "/")+"/"+k+": required field missing")
			}
			return
		}
		details = append(details, path+": "+strings.Join(e.ErrorKind.KeywordPath(), "/"))
	}
	if e, ok := cause.(*jsonschema.ValidationError); ok {
		walk(e)
	}
	if len(details) == 0 {
		details = append(details, "structure does not match current Schema")
	}
	return &ValidationFailure{Surface: surface, Raw: append([]byte(nil), raw...), Reason: strings.Join(details, "; ")}
}