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"
)

// ftsMockSource is the Source of the opportunities the mock source fetches.
const ftsMockSource = "FTSMock"

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

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

// fetchFTSMock fetches everything updated since since from the mock Find a
// Tender server. The mock serves the real API's format, so the converter
// marks the opportunities as Find a Tender's; their Source is set to
// ftsMockSource here instead. Finding nothing returns ErrNoNewReleases, so
// the worker still moves its checkpoint on.
func fetchFTSMock(
	ctx context.Context,
	logger *slog.Logger,
	conf *config.JSCSourceFTSMock,
	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
	}

	for _, opportunity := range opportunities {
		opportunity.Source = ftsMockSource
	}

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

	return opportunities, nil
}