// Package database provides the persistence layer for kereru-forms.
//
// The Store interface deliberately hides SQL details so additional providers
// (PostgreSQL, MariaDB) can be added later without changing the API layer.
package database

import (
	"context"
	"encoding/json"
	"errors"
	"time"
)

// Common persistence errors.
var (
	ErrNotFound      = errors.New("not found")
	ErrConflict      = errors.New("conflict")
	ErrAccessCode    = errors.New("access code is not valid")
	ErrCodeAlreadyIn = errors.New("access code has already been used")
)

// QuestionOption is a selectable value for a select question.
type QuestionOption struct {
	Value string `json:"value"`
	Label string `json:"label"`
}

// Section groups questions within a form.
type Section struct {
	ID         string
	FormID     string
	Position   int
	Identifier string
	Title      *string
	Description *string
}

// Question is a single question belonging to a form version.
type Question struct {
	ID          string
	FormID      string
	SectionID   *string
	Position    int
	Key         string
	Label       string
	Description *string
	Type        string
	Required    bool
	Options     []QuestionOption
	MinValue    *float64
	MaxValue    *float64
	Placeholder *string
	Multiline   bool
}

// Form is a concrete version of a logical form.
type Form struct {
	ID                        string
	FormGroupID               string
	Version                   int
	Title                     string
	Description               *string
	Introduction              *string
	IsActive                  bool
	RequiresAccessCode        bool
	SignatureRequired         bool
	ExternalReferenceRequired bool
	ExternalReferenceLabel    *string
	LogoURL                   *string
	PDFURL                    *string
	CompanyName               *string
	ContactEmail              *string
	ContactPhone              *string
	ContactURL                *string
	CreatedAt                 time.Time
	UpdatedAt                 time.Time
	Questions                 []Question
	Sections                  []Section
}

// FormSummary is a lightweight form listing entry.
type FormSummary struct {
	ID                        string
	FormGroupID               string
	Version                   int
	Title                     string
	Description               *string
	LogoURL                   *string
	PDFURL                    *string
	ExternalReferenceRequired bool
	ExternalReferenceLabel    *string
	IsActive                  bool
	QuestionCount             int
	CreatedAt                 time.Time
	UpdatedAt                 time.Time
}

// Answer is a captured answer inside a submission.
type Answer struct {
	QuestionID  string
	QuestionKey string
	Value       json.RawMessage
}

// Signature is a captured digital signature.
type Signature struct {
	Type     string    `json:"type"`
	DataURL  string    `json:"dataUrl"`
	Name     string    `json:"name"`
	Title    *string   `json:"title,omitempty"`
	SignedAt time.Time `json:"signedAt"`
}

// Submission is a completed form response.
type Submission struct {
	ID                string
	FormID            string
	FormVersion       int
	UserID            string
	UserIDType        string
	SubmittedAt       time.Time
	IPAddress         *string
	UserAgent         *string
	Locale            *string
	Timezone          *string
	Place             *string
	Referer           *string
	ExternalReference *string
	Signature         *Signature
	OfflinePDFName    *string
	OfflinePDF        []byte
	Answers           []Answer
}

// SubmissionSummary is a lightweight submission listing entry.
type SubmissionSummary struct {
	ID                string
	FormID            string
	FormVersion       int
	UserID            string
	UserIDType        string
	ExternalReference *string
	SubmittedAt       time.Time
}

// AccessCode is a single-use code granting access to a form.
type AccessCode struct {
	ID        string
	FormID    string
	Code      string
	Used      bool
	UsedAt    *time.Time
	CreatedAt time.Time
}

// Store is the persistence contract used by the API layer.
type Store interface {
	Close() error

	CreateForm(ctx context.Context, form *Form) error
	UpdateForm(ctx context.Context, form *Form) error
	GetForm(ctx context.Context, id string) (*Form, error)
	ListForms(ctx context.Context, includeInactive bool) ([]FormSummary, error)
	SetFormActive(ctx context.Context, id string, active bool) error
	DeleteForm(ctx context.Context, id string) error

	CreateSubmission(ctx context.Context, submission *Submission, accessCode string) error
	GetSubmission(ctx context.Context, id string) (*Submission, error)
	GetSubmissionOfflinePDF(ctx context.Context, id string) ([]byte, string, error)
	ListSubmissions(ctx context.Context, formID string) ([]SubmissionSummary, error)

	CreateAccessCodes(ctx context.Context, codes []AccessCode) error
	ListAccessCodes(ctx context.Context, formID string) ([]AccessCode, error)

	Ping(ctx context.Context) error
}