package validate

import (
	"context"
	"fmt"
	"net/url"
	"strconv"
	"strings"

	"github.com/santhosh-tekuri/jsonschema/v6"
)

// These schema-bearing positions mirror the inherited subschema tables in
// jsonschema/v6 v6.0.2 draft.go. Annotation objects are deliberately excluded.
func checkSchemaLocations(ctx context.Context, compiler *jsonschema.Compiler, resourceURL string, document any, pointer string, compiled *jsonschema.Schema) error {
	if err := ctx.Err(); err != nil {
		return err
	}
	object, ok := document.(map[string]any)
	if !ok {
		return nil
	}
	version := compiled.DraftVersion
	mapKeys := []string{"definitions", "properties", "patternProperties", "dependencies"}
	singleKeys := []string{"not", "additionalProperties", "items", "additionalItems"}
	arrayKeys := []string{"allOf", "anyOf", "oneOf", "items"}
	if version >= 6 {
		singleKeys = append(singleKeys, "propertyNames", "contains")
	}
	if version >= 7 {
		singleKeys = append(singleKeys, "if", "then", "else")
	}
	if version >= 2019 {
		mapKeys = append(mapKeys, "$defs", "dependentSchemas")
		singleKeys = append(singleKeys, "unevaluatedProperties", "unevaluatedItems", "contentSchema")
	}
	if version >= 2020 {
		arrayKeys = append(arrayKeys, "prefixItems")
	}
	visit := func(value any, segments ...string) error {
		switch value.(type) {
		case map[string]any, bool:
		default:
			return nil
		}
		childPointer := pointer
		for _, segment := range segments {
			childPointer += "/" + strings.ReplaceAll(strings.ReplaceAll(segment, "~", "~0"), "/", "~1")
		}
		parsed, err := url.Parse(resourceURL)
		if err != nil {
			return err
		}
		parsed.Fragment = childPointer
		child, err := compileJSONSchema(ctx, parsed.String(), compiler.Compile)
		if err != nil {
			return fmt.Errorf("compile declared schema %q: %w", childPointer, err)
		}
		return checkSchemaLocations(ctx, compiler, resourceURL, value, childPointer, child)
	}
	for _, key := range mapKeys {
		entries, ok := object[key].(map[string]any)
		if !ok {
			continue
		}
		for name, value := range entries {
			if err := visit(value, key, name); err != nil {
				return err
			}
		}
	}
	for _, key := range singleKeys {
		if value, ok := object[key]; ok {
			if err := visit(value, key); err != nil {
				return err
			}
		}
	}
	for _, key := range arrayKeys {
		entries, ok := object[key].([]any)
		if !ok {
			continue
		}
		for i, value := range entries {
			if err := visit(value, key, strconv.Itoa(i)); err != nil {
				return err
			}
		}
	}
	return ctx.Err()
}