package contract

import (
	"time"
	"unicode/utf8"
)

// Cursor is an opaque repository-issued continuation token. Clients must not
// parse, increment, or reuse it for another run/filter. Empty starts a scan;
// an empty nextCursor ends it. An empty page with a cursor is not end-of-scan.
// Repositories validate token contents and query binding with ErrInvalidArgument.
type Cursor string

const (
	DefaultPageLimit = 100
	MaxPageLimit     = 500
)

type PageRequest struct {
	Cursor Cursor `json:"cursor,omitempty"`
	Limit  int    `json:"limit,omitempty"`
}

// Normalized must be called at both HTTP and repository boundaries. Limits
// outside the bounds are rejected, not silently truncated.
func (p PageRequest) Normalized() (PageRequest, error) {
	if p.Limit == 0 {
		p.Limit = DefaultPageLimit
	}
	if p.Limit < 1 || p.Limit > MaxPageLimit {
		return PageRequest{}, invalid("limit must be between 1 and %d", MaxPageLimit)
	}
	return p, nil
}

// Failure is the bounded public projection, not the replay payload. Legacy
// free-form failureType/message fields remain available in FailureRecord.
type Failure struct {
	TaskID        string        `json:"taskId"`
	CardID        int64         `json:"cardId"`
	ErrorCategory ErrorCategory `json:"errorCategory"`
	ErrorMessage  string        `json:"errorMessage"`
	FailedAt      time.Time     `json:"failedAt"`
	Round         int           `json:"round"`
}

func (f Failure) Validate() error {
	if f.TaskID == "" || f.Round < 0 || len(f.ErrorMessage) > MaxErrorMessageBytes || !utf8.ValidString(f.ErrorMessage) {
		return invalid("invalid failure summary")
	}
	return nil
}

type FailurePage struct {
	Items      []Failure `json:"items"`
	NextCursor Cursor    `json:"nextCursor"`
}

// FailureRecord preserves the existing persisted payload without changing
// review semantics or discarding fields needed to reconstruct replay tasks.
type FailureRecord struct {
	Version       int    `json:"version"`
	TaskID        string `json:"taskId"`
	OriginalRunID string `json:"originalRunId"`
	LatestRunID   string `json:"latestRunId"`
	QueryMonth    string `json:"queryMonth"`
	Operation     string `json:"operation"`
	CardID        int64  `json:"cardId"`
	ICCID         string `json:"iccid"`
	MSISDN        string `json:"msisdn"`
	IMSI          string `json:"imsi"`
	ChanKey       string `json:"chanKey"`
	TempKey       string `json:"tempKey"`
	// PackageCode is additive; older failure records decode it as empty.
	PackageCode   string    `json:"packageCode,omitempty"`
	Carrier       string    `json:"carrier"`
	FailureType   string    `json:"failureType"`
	Round         int       `json:"round"`
	Attempts      int       `json:"attempts"`
	Code          int       `json:"code"`
	ErrCode       string    `json:"errCode"`
	Message       string    `json:"message"`
	ReviewStatus  string    `json:"reviewStatus"`
	ReviewRemark  string    `json:"reviewRemark"`
	ReviewedBy    string    `json:"reviewedBy"`
	ReviewedAt    string    `json:"reviewedAt"`
	RetryCycle    int       `json:"retryCycle"`
	ReplayRunID   string    `json:"replayRunId"`
	FirstFailedAt time.Time `json:"firstFailedAt"`
	LastFailedAt  time.Time `json:"lastFailedAt"`
}

func (f FailureRecord) Summary() Failure {
	return Failure{
		TaskID: f.TaskID, CardID: f.CardID, ErrorCategory: NormalizeErrorCategory(f.FailureType),
		ErrorMessage: BoundedErrorMessage(f.Message), FailedAt: f.LastFailedAt, Round: f.Round,
	}
}

// FailureEntry carries an opaque version for conditional source cleanup. It
// must identify the precise record read, not just its reusable task ID.
type FailureEntry struct {
	Record  FailureRecord `json:"record"`
	Version string        `json:"-"`
}

type FailureRecordPage struct {
	Items      []FailureEntry `json:"items"`
	NextCursor Cursor         `json:"nextCursor"`
}

// Task keeps the existing queue member serialization. The scheduling score
// must never be part of the JSON member or producer retries lose idempotency.
type Task struct {
	TaskID     string `json:"taskId"`
	RunID      string `json:"runId"`
	Operation  string `json:"operation"`
	QueryMonth string `json:"queryMonth"`
	ChanKey    string `json:"chanKey"`
	TempKey    string `json:"tempKey"`
	Operator   int    `json:"operator,omitempty"`
	CardID     int64  `json:"cardId"`
	ICCID      string `json:"iccid"`
	MSISDN     string `json:"msisdn"`
	IMSI       string `json:"imsi"`
	// PackageCode is additive; older members decode it as empty.
	PackageCode   string `json:"packageCode,omitempty"`
	NextExecuteAt int64  `json:"-"`
}