package fetcher

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

	"git.avsdev.uk/Go/job-search/internal/config"
	"git.avsdev.uk/Go/job-search/internal/findatender"
	"git.avsdev.uk/Go/job-search/internal/types"
	"git.avsdev.uk/Go/job-search/internal/util"
)

// runFindATender polls Find a Tender every configured interval until ctx
// is cancelled, passing what each run fetches to save.
func runFindATender(
	ctx context.Context,
	logger *slog.Logger,
	conf *config.JSCSourceFindATender,
	save saveFunc,
	since time.Time,
) error {
	if conf.APIRoot == "" {
		return errors.New("fetcher: sources.find_a_tender.api_root is not set")
	}

	worker := util.Worker{
		Logger:   tagged(logger),
		Name:     "FindATender",
		Interval: conf.Interval,
		Task: func(ctx context.Context, since time.Time) error {
			opportunities, err := fetchFindATender(ctx, logger, conf, since)
			if err != nil {
				return err
			}
			return save(ctx, logger, opportunities)
		},
	}
	return worker.Run(ctx, since)
}

// fetchFindATender fetches everything updated since since from Find a
// Tender. Finding nothing returns ErrNoNewReleases, so the worker still moves
// its checkpoint on.
func fetchFindATender(
	ctx context.Context,
	logger *slog.Logger,
	conf *config.JSCSourceFindATender,
	since time.Time,
) ([]*types.Opportunity, error) {
	opportunities, err := util.AwaitTask(
		ctx,
		func() ([]*types.Opportunity, error) {
			findATender := findatender.New(
				conf.APIRoot, findatender.WithLogger(logger),
			)
			defer findATender.Shutdown()
			return findATender.With(ctx).FetchAll(since, true)
		},
	)
	if errors.Is(err, findatender.ErrNoReleases) {
		return nil, ErrNoNewReleases
	}
	if err != nil {
		return nil, err
	}

	tagged(logger).Info("fetched opportunities", "count", len(opportunities))

	return opportunities, nil
}