internal

type Codec interface {
	// Decode decodes a single JSON operation into an Op.
	Decode(operation Operation) (Op, error)
	// DecodeSlice decodes a slice of JSON operations into Ops.
	DecodeSlice(operations []Operation) ([]Op, error)
	// Encode encodes an Op into a JSON operation.
	Encode(op Op) (Operation, error)
	// EncodeSlice encodes a slice of Ops into JSON operations.
	EncodeSlice(ops []Op) ([]Operation, error)
}

type CompactOperation = []any

type CreateRegexMatcher func(pattern string, ignoreCase bool) RegexMatcher

type Document interface {
	~[]byte | ~string | map[string]any | any
}

type JSONPatchOptions struct {
	// CreateMatcher overrides regex compilation for pattern operations.
	CreateMatcher CreateRegexMatcher
}

type JSONPatchType string

type Op interface {
	// Op returns the operation type string (e.g. "add", "remove").
	Op() OpType
	// Code returns the numeric code for the operation.
	Code() int
	// Path returns the JSON Pointer path as a string slice.
	Path() []string
	// Apply applies the operation to the document, returning the result and any error.
	Apply(doc any) (OpResult[any], error)
	// ToJSON serializes the operation to standard JSON Patch format.
	ToJSON() (Operation, error)
	// ToCompact serializes the operation to compact array format.
	ToCompact() (CompactOperation, error)
	// Validate checks that the operation parameters are valid.
	Validate() error
}

type OpResult[T Document] struct {
	// Doc is the document after the operation completes.
	Doc T `json:"doc"`
	// Old is the previous value returned by operations that expose one.
	Old any `json:"old,omitempty"`
}

type OpType string

type Operation struct {
	// Op names the operation to apply.
	Op string `json:"op"`
	// Path is the target JSON Pointer.
	Path string `json:"path"`
	// Value holds the operation payload when the operation uses one.
	Value any `json:"value,omitempty"`
	// From is the source JSON Pointer for move and copy.
	From string `json:"from,omitempty"`

	// Inc is the numeric delta for inc. It is never omitted because 0 is valid.
	Inc float64 `json:"inc"`
	// Pos is the string or array position for operations that use one. It is never omitted because 0 is valid.
	Pos int `json:"pos"`
	// Str is the string operand for string-editing operations. It is never omitted because the empty string is valid.
	Str string `json:"str"`
	// Len is the requested length for operations that use one. It is never omitted because 0 is valid.
	Len int `json:"len"`

	// Not inverts supported predicate operations.
	Not bool `json:"not,omitempty"`
	// Type holds one JSON type name or a list of JSON type names.
	Type any `json:"type,omitempty"`
	// IgnoreCase makes string matching case-insensitive when supported.
	IgnoreCase bool `json:"ignore_case,omitempty"`
	// Apply contains nested predicate operations for and, or, and not.
	Apply []Operation `json:"apply,omitempty"`

	// Props supplies object properties for extend.
	Props map[string]any `json:"props,omitempty"`
	// DeleteNull removes properties whose incoming value is null during extend.
	DeleteNull bool `json:"deleteNull,omitempty"`
	// OldValue carries the expected previous value for operations that use it.
	OldValue any `json:"oldValue,omitempty"`
}

type Option func(*Options)

type Options struct {
	// Mutate enables in-place updates instead of cloning the input first.
	Mutate bool
	// CreateMatcher overrides regex compilation for pattern operations.
	CreateMatcher CreateRegexMatcher
}

type PatchResult[T Document] struct {
	// Doc is the final patched document.
	Doc T
	// Res contains the per-operation results in application order.
	Res []OpResult[T]
}

type PredicateOp interface {
	Op
	// Test evaluates the predicate against the document.
	Test(doc any) (bool, error)
	// Not reports whether the predicate is negated.
	Not() bool
}

type RegexMatcher func(value string) bool

type SecondOrderPredicateOp interface {
	PredicateOp
	// Ops returns the sub-predicate operations.
	Ops() []PredicateOp
}