package store

import (
	"fmt"
	"path/filepath"
	"time"

	"github.com/google/uuid"
	"printer.backend/internal/model"
	"printer.backend/internal/paths"
)

// PrintJobStore persists print jobs as JSON files.
type PrintJobStore struct {
	dir string
}

// NewPrintJobStore creates a store under dir (default data/print_jobs).
func NewPrintJobStore(dir string) *PrintJobStore {
	if dir == "" {
		dir = paths.PrintJobsDir
	}
	return &PrintJobStore{dir: dir}
}

// List returns all print jobs sorted by creation time (newest first).
func (s *PrintJobStore) List() ([]model.PrintJob, error) {
	return listFromDir(s.dir,
		func(name string) bool { return filepath.Ext(name) == ".json" },
		"print jobs dir",
		func(j model.PrintJob) time.Time { return j.CreatedAt },
	)
}

// Get returns a print job by ID.
func (s *PrintJobStore) Get(id string) (model.PrintJob, error) {
	list, err := s.List()
	if err != nil {
		return model.PrintJob{}, err
	}
	j, err := findByID(list, id, func(j model.PrintJob) string { return j.ID })
	if err != nil {
		return model.PrintJob{}, fmt.Errorf("print job not found: %s", id)
	}
	if j.OrderIDs == nil {
		j.OrderIDs = []string{}
	}
	return j, nil
}

// Save writes a new print job and assigns an ID when empty.
func (s *PrintJobStore) Save(j model.PrintJob) (model.PrintJob, error) {
	if err := ensureDir(s.dir); err != nil {
		return model.PrintJob{}, err
	}
	if j.ID == "" {
		j.ID = uuid.NewString()
	}
	if j.OrderIDs == nil {
		j.OrderIDs = []string{}
	}
	now := stampNew(&j.CreatedAt)
	j.CreatedAt = now
	j.UpdatedAt = now

	path := filepath.Join(s.dir, j.ID+".json")
	if err := writeJSON(path, j); err != nil {
		return model.PrintJob{}, fmt.Errorf("write print job: %w", err)
	}
	return j, nil
}

// Update replaces an existing print job (preserves id and created_at).
func (s *PrintJobStore) Update(id string, j model.PrintJob) (model.PrintJob, error) {
	existing, err := s.Get(id)
	if err != nil {
		return model.PrintJob{}, err
	}
	j.ID = existing.ID
	j.CreatedAt = existing.CreatedAt
	j.UpdatedAt = time.Now().UTC()
	if j.OrderIDs == nil {
		j.OrderIDs = []string{}
	}

	path := filepath.Join(s.dir, id+".json")
	if err := writeJSON(path, j); err != nil {
		return model.PrintJob{}, fmt.Errorf("write print job: %w", err)
	}
	return j, nil
}

// Delete removes a print job by ID.
func (s *PrintJobStore) Delete(id string) error {
	path := filepath.Join(s.dir, id+".json")
	return removeFile(path, fmt.Sprintf("print job not found: %s", id))
}