package worker

import (
	"context"
	"fmt"
	"log/slog"
	"time"

	"git.toki-labs.com/toki/gito/services/core/internal/config"
	"git.toki-labs.com/toki/gito/services/core/internal/core"
)

type OperationPicker interface {
	PickQueuedOperation(ctx context.Context, now time.Time) (core.Operation, bool, error)
}

type Clock interface {
	Now() time.Time
}

type realClock struct{}

func (realClock) Now() time.Time {
	return time.Now()
}

type Runner struct {
	cfg    config.Config
	logger *slog.Logger
	picker OperationPicker
	clock  Clock
}

func NewRunner(cfg config.Config, logger *slog.Logger, picker OperationPicker, clock Clock) *Runner {
	if clock == nil {
		clock = realClock{}
	}
	return &Runner{
		cfg:    cfg,
		logger: logger,
		picker: picker,
		clock:  clock,
	}
}

func (r *Runner) Run() error {
	return r.RunOnce(context.Background())
}

func (r *Runner) RunOnce(ctx context.Context) error {
	if !r.cfg.WorkerEnabled {
		r.logger.Info("worker disabled")
		return nil
	}

	if r.picker == nil {
		r.logger.Warn("worker picker not configured")
		return nil
	}

	op, ok, err := r.picker.PickQueuedOperation(ctx, r.clock.Now())
	if err != nil {
		r.logger.Error("failed to pick operation", "error", err)
		return fmt.Errorf("pick operation: %w", err)
	}

	if !ok {
		r.logger.Debug("no pending operation found")
		return nil
	}

	r.logger.Info("picked operation", "operation_id", op.ID, "type", op.Type)
	return nil
}