package template

import (
	"reflect"

	"git.warky.dev/wdevs/relspecgo/pkg/reflectutil"
)

// Get safely gets a value from a map by key
// Usage: {{ get .Metadata "key" }}
func Get(m interface{}, key interface{}) interface{} {
	return reflectutil.MapGet(m, key)
}

// GetOr safely gets a value from a map with a default fallback
// Usage: {{ getOr .Metadata "key" "default" }}
func GetOr(m interface{}, key interface{}, defaultValue interface{}) interface{} {
	result := Get(m, key)
	if result == nil {
		return defaultValue
	}
	return result
}

// GetPath safely gets a nested value using dot notation
// Usage: {{ getPath .Config "database.connection.host" }}
func GetPath(m interface{}, path string) interface{} {
	return reflectutil.GetNestedValue(m, path)
}

// GetPathOr safely gets a nested value with a default fallback
// Usage: {{ getPathOr .Config "database.connection.host" "localhost" }}
func GetPathOr(m interface{}, path string, defaultValue interface{}) interface{} {
	result := GetPath(m, path)
	if result == nil {
		return defaultValue
	}
	return result
}

// SafeIndex safely gets an element from a slice by index
// Usage: {{ safeIndex .Tables 0 }}
func SafeIndex(slice interface{}, index int) interface{} {
	return reflectutil.SliceIndex(slice, index)
}

// SafeIndexOr safely gets an element from a slice with a default fallback
// Usage: {{ safeIndexOr .Tables 0 "default" }}
func SafeIndexOr(slice interface{}, index int, defaultValue interface{}) interface{} {
	result := SafeIndex(slice, index)
	if result == nil {
		return defaultValue
	}
	return result
}

// Has checks if a key exists in a map
// Usage: {{ if has .Metadata "key" }}...{{ end }}
func Has(m interface{}, key interface{}) bool {
	v := reflect.ValueOf(m)

	// Dereference pointers
	for v.Kind() == reflect.Ptr {
		if v.IsNil() {
			return false
		}
		v = v.Elem()
	}

	if v.Kind() != reflect.Map {
		return false
	}

	keyVal := reflect.ValueOf(key)
	return v.MapIndex(keyVal).IsValid()
}

// HasPath checks if a nested path exists
// Usage: {{ if hasPath .Config "database.connection.host" }}...{{ end }}
func HasPath(m interface{}, path string) bool {
	return GetPath(m, path) != nil
}

// Keys returns all keys from a map
// Usage: {{ range keys .Metadata }}...{{ end }}
func Keys(m interface{}) []interface{} {
	return reflectutil.MapKeys(m)
}

// Values returns all values from a map
// Usage: {{ range values .Table.Columns }}...{{ end }}
func Values(m interface{}) []interface{} {
	return reflectutil.MapValues(m)
}

// Merge merges multiple maps into a new map
// Usage: {{ $merged := merge .Map1 .Map2 }}
func Merge(maps ...interface{}) map[interface{}]interface{} {
	result := make(map[interface{}]interface{})

	for _, m := range maps {
		v := reflect.ValueOf(m)

		// Dereference pointers
		for v.Kind() == reflect.Ptr {
			if v.IsNil() {
				continue
			}
			v = v.Elem()
		}

		if v.Kind() != reflect.Map {
			continue
		}

		iter := v.MapRange()
		for iter.Next() {
			result[iter.Key().Interface()] = iter.Value().Interface()
		}
	}

	return result
}

// Pick returns a new map with only the specified keys
// Usage: {{ $subset := pick .Metadata "name" "description" }}
func Pick(m interface{}, keys ...interface{}) map[interface{}]interface{} {
	result := make(map[interface{}]interface{})
	v := reflect.ValueOf(m)

	// Dereference pointers
	for v.Kind() == reflect.Ptr {
		if v.IsNil() {
			return result
		}
		v = v.Elem()
	}

	if v.Kind() != reflect.Map {
		return result
	}

	for _, key := range keys {
		keyVal := reflect.ValueOf(key)
		mapVal := v.MapIndex(keyVal)
		if mapVal.IsValid() {
			result[key] = mapVal.Interface()
		}
	}

	return result
}

// Omit returns a new map without the specified keys
// Usage: {{ $filtered := omit .Metadata "internal" "private" }}
func Omit(m interface{}, keys ...interface{}) map[interface{}]interface{} {
	result := make(map[interface{}]interface{})
	v := reflect.ValueOf(m)

	// Dereference pointers
	for v.Kind() == reflect.Ptr {
		if v.IsNil() {
			return result
		}
		v = v.Elem()
	}

	if v.Kind() != reflect.Map {
		return result
	}

	// Create a set of keys to omit
	omitSet := make(map[interface{}]bool)
	for _, key := range keys {
		omitSet[key] = true
	}

	// Add all keys that are not in the omit set
	iter := v.MapRange()
	for iter.Next() {
		key := iter.Key().Interface()
		if !omitSet[key] {
			result[key] = iter.Value().Interface()
		}
	}

	return result
}

// SliceContains checks if a slice contains a value
// Usage: {{ if sliceContains .Names "admin" }}...{{ end }}
func SliceContains(slice interface{}, value interface{}) bool {
	v := reflect.ValueOf(slice)
	v, ok := reflectutil.Deref(v)
	if !ok {
		return false
	}

	if v.Kind() != reflect.Slice && v.Kind() != reflect.Array {
		return false
	}

	for i := 0; i < v.Len(); i++ {
		if reflectutil.DeepEqual(v.Index(i).Interface(), value) {
			return true
		}
	}

	return false
}

// IndexOf returns the index of a value in a slice, or -1 if not found
// Usage: {{ $idx := indexOf .Names "admin" }}
func IndexOf(slice interface{}, value interface{}) int {
	v := reflect.ValueOf(slice)
	v, ok := reflectutil.Deref(v)
	if !ok {
		return -1
	}

	if v.Kind() != reflect.Slice && v.Kind() != reflect.Array {
		return -1
	}

	for i := 0; i < v.Len(); i++ {
		if reflectutil.DeepEqual(v.Index(i).Interface(), value) {
			return i
		}
	}

	return -1
}

// Pluck extracts a field from each element in a slice
// Usage: {{ $names := pluck .Tables "Name" }}
func Pluck(slice interface{}, field string) []interface{} {
	v := reflect.ValueOf(slice)

	// Dereference pointers
	for v.Kind() == reflect.Ptr {
		if v.IsNil() {
			return []interface{}{}
		}
		v = v.Elem()
	}

	if v.Kind() != reflect.Slice && v.Kind() != reflect.Array {
		return []interface{}{}
	}

	result := make([]interface{}, 0, v.Len())
	for i := 0; i < v.Len(); i++ {
		item := v.Index(i)

		// Dereference item pointers
		for item.Kind() == reflect.Ptr {
			if item.IsNil() {
				result = append(result, nil)
				continue
			}
			item = item.Elem()
		}

		switch item.Kind() {
		case reflect.Struct:
			fieldVal := item.FieldByName(field)
			if fieldVal.IsValid() {
				result = append(result, fieldVal.Interface())
			} else {
				result = append(result, nil)
			}

		case reflect.Map:
			keyVal := reflect.ValueOf(field)
			mapVal := item.MapIndex(keyVal)
			if mapVal.IsValid() {
				result = append(result, mapVal.Interface())
			} else {
				result = append(result, nil)
			}

		default:
			result = append(result, nil)
		}
	}

	return result
}