tiki/task/validation.go

package task

import (
	"fmt"
	"strings"
	"time"

	"github.com/boolean-maybe/tiki/config"
)

// Priority validation constants
const (
	MinPriority     = 1
	MaxPriority     = 5
	DefaultPriority = 3 // Medium
)

// ValidateTitle returns an error message if the task title is invalid.
func ValidateTitle(t *Task) string {
	title := strings.TrimSpace(t.Title)
	if title == "" {
		return "title is required"
	}
	const maxTitleLength = 200
	if len(title) > maxTitleLength {
		return fmt.Sprintf("title exceeds maximum length of %d characters", maxTitleLength)
	}
	return ""
}

// ValidateStatus returns an error message if the task status is invalid.
func ValidateStatus(t *Task) string {
	if config.GetStatusRegistry().IsValid(string(t.Status)) {
		return ""
	}
	return fmt.Sprintf("invalid status value: %s", t.Status)
}

// ValidateType returns an error message if the task type is invalid.
func ValidateType(t *Task) string {
	if requireTypeRegistry().IsValid(t.Type) {
		return ""
	}
	return fmt.Sprintf("invalid type value: %s", t.Type)
}

// ValidatePriority returns an error message if the task priority is out of range.
func ValidatePriority(t *Task) string {
	if t.Priority < MinPriority || t.Priority > MaxPriority {
		return fmt.Sprintf("priority must be between %d and %d", MinPriority, MaxPriority)
	}
	return ""
}

// ValidatePoints returns an error message if story points are out of range.
func ValidatePoints(t *Task) string {
	if t.Points == 0 {
		return ""
	}
	const minPoints = 1
	maxPoints := config.GetMaxPoints()
	if t.Points < minPoints || t.Points > maxPoints {
		return fmt.Sprintf("story points must be between %d and %d", minPoints, maxPoints)
	}
	return ""
}

// ValidateDependsOn returns an error message if any dependency ID is malformed.
func ValidateDependsOn(t *Task) string {
	for _, dep := range t.DependsOn {
		if !IsValidTikiIDFormat(dep) {
			return fmt.Sprintf("invalid tiki ID format: %s (expected TIKI-XXXXXX)", dep)
		}
	}
	return ""
}

// ValidateDue returns an error message if the due date is not normalized to midnight UTC.
func ValidateDue(t *Task) string {
	if t.Due.IsZero() {
		return ""
	}
	if t.Due.Hour() != 0 || t.Due.Minute() != 0 || t.Due.Second() != 0 || t.Due.Nanosecond() != 0 || t.Due.Location() != time.UTC {
		return "due date must be normalized to midnight UTC (use date-only format)"
	}
	return ""
}

// ValidateRecurrence returns an error message if the recurrence pattern is invalid.
func ValidateRecurrence(t *Task) string {
	if t.Recurrence == RecurrenceNone {
		return ""
	}
	if !IsValidRecurrence(t.Recurrence) {
		return fmt.Sprintf("invalid recurrence pattern: %s", t.Recurrence)
	}
	return ""
}

// IsValidPriority checks if a priority value is within the valid range.
func IsValidPriority(priority int) bool {
	return priority >= MinPriority && priority <= MaxPriority
}

// IsValidPoints checks if a points value is within the valid range.
func IsValidPoints(points int) bool {
	if points == 0 {
		return true
	}
	if points < 0 {
		return false
	}
	return points <= config.GetMaxPoints()
}

// IsValidTikiIDFormat checks if a string matches the TIKI-XXXXXX format
// where X is an uppercase alphanumeric character.
func IsValidTikiIDFormat(id string) bool {
	if len(id) != 11 || id[:5] != "TIKI-" {
		return false
	}
	for _, c := range id[5:] {
		if (c < 'A' || c > 'Z') && (c < '0' || c > '9') {
			return false
		}
	}
	return true
}

// AllValidators returns the complete list of field validation functions.
// Each returns an error message (empty string = valid).
func AllValidators() []func(*Task) string {
	return []func(*Task) string{
		ValidateTitle,
		ValidateStatus,
		ValidateType,
		ValidatePriority,
		ValidatePoints,
		ValidateDependsOn,
		ValidateDue,
		ValidateRecurrence,
	}
}