package topdata

import (
	"fmt"
	"strings"
)

type familyIdentity struct {
	Parent string
	Child  string
}

type familyExpansionSource struct {
	Dataset   string
	Column    string
	Predicate string
}

type familyExpansionSpec struct {
	Family      string
	FamilyKey   string
	Template    string
	ChildSource familyExpansionSource
}

func splitFamilyExpansionIdentity(text string) familyIdentity {
	text = strings.TrimSpace(text)
	if text == "" {
		return familyIdentity{}
	}
	if idx := strings.Index(text, "_"); idx > 0 && idx < len(text)-1 {
		return familyIdentity{
			Parent: text[:idx],
			Child:  text[idx+1:],
		}
	}
	return familyIdentity{Parent: text}
}

func parseFamilyExpansionSource(raw any) (familyExpansionSource, error) {
	if raw == nil {
		return familyExpansionSource{}, fmt.Errorf("child_source is required")
	}
	obj, ok := raw.(map[string]any)
	if !ok {
		return familyExpansionSource{}, fmt.Errorf("child_source must be an object")
	}
	dataset, ok := obj["dataset"].(string)
	if !ok || strings.TrimSpace(dataset) == "" {
		return familyExpansionSource{}, fmt.Errorf("child_source.dataset must be a non-empty string")
	}
	source := familyExpansionSource{
		Dataset: strings.TrimSpace(dataset),
	}
	if column, ok := obj["column"].(string); ok && strings.TrimSpace(column) != "" {
		source.Column = strings.TrimSpace(column)
	}
	if predicate, ok := obj["predicate"].(string); ok && strings.TrimSpace(predicate) != "" {
		source.Predicate = strings.TrimSpace(predicate)
	}
	return source, nil
}

func parseFamilyExpansionSpec(path string, obj map[string]any) (familyExpansionSpec, error) {
	family, ok := obj["family"].(string)
	if !ok || strings.TrimSpace(family) == "" {
		return familyExpansionSpec{}, fmt.Errorf("generated file %s: family must be a non-empty string", path)
	}
	familyKey, ok := obj["family_key"].(string)
	if !ok || strings.TrimSpace(familyKey) == "" {
		return familyExpansionSpec{}, fmt.Errorf("generated file %s: family_key must be a non-empty string", path)
	}
	template, ok := obj["template"].(string)
	if !ok || strings.TrimSpace(template) == "" {
		return familyExpansionSpec{}, fmt.Errorf("generated file %s: template must be a non-empty string", path)
	}
	source, err := parseFamilyExpansionSource(obj["child_source"])
	if err != nil {
		return familyExpansionSpec{}, fmt.Errorf("generated file %s: %w", path, err)
	}
	return familyExpansionSpec{
		Family:      strings.TrimSpace(family),
		FamilyKey:   strings.TrimSpace(familyKey),
		Template:    strings.TrimSpace(template),
		ChildSource: source,
	}, nil
}

func familyMetadata(parent, child, source, template string) map[string]any {
	meta := map[string]any{
		"parent": strings.TrimSpace(parent),
	}
	if strings.TrimSpace(child) != "" {
		meta["child"] = strings.TrimSpace(child)
	}
	if strings.TrimSpace(source) != "" {
		meta["source"] = strings.TrimSpace(source)
	}
	if strings.TrimSpace(template) != "" {
		meta["template"] = strings.TrimSpace(template)
	}
	return map[string]any{"family": meta}
}

func parseFamilyMetadata(raw any) (map[string]any, error) {
	obj, ok := raw.(map[string]any)
	if !ok {
		return nil, fmt.Errorf("must be an object")
	}
	parent, ok := obj["parent"].(string)
	if !ok || strings.TrimSpace(parent) == "" {
		return nil, fmt.Errorf("parent must be a non-empty string")
	}
	meta := map[string]any{
		"parent": strings.TrimSpace(parent),
	}
	if child, ok := obj["child"].(string); ok && strings.TrimSpace(child) != "" {
		meta["child"] = strings.TrimSpace(child)
	}
	if source, ok := obj["source"].(string); ok && strings.TrimSpace(source) != "" {
		meta["source"] = strings.TrimSpace(source)
	}
	if template, ok := obj["template"].(string); ok && strings.TrimSpace(template) != "" {
		meta["template"] = strings.TrimSpace(template)
	}
	return meta, nil
}

func childTokenFromExpandedKey(key, parent string) string {
	key = strings.TrimSpace(key)
	key = strings.TrimPrefix(key, "feat:")
	if strings.HasPrefix(key, parent+"_") {
		return strings.TrimPrefix(key, parent+"_")
	}
	if strings.HasPrefix(key, parent) {
		return strings.TrimPrefix(key, parent)
	}
	return ""
}