package custom_errors

import (
	"context"
	"fmt"
	"sync"

	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
)

type LoaderError struct {
	Batch models.Batch
	Msg   string
}

func (e *LoaderError) Error() string {
	return e.Msg
}

func LoaderErrorHandler(
	ctx context.Context,
	retryConfig config.RetryConfig,
	maxChunkErrors int,
	chErrorsIn <-chan LoaderError,
	chBatchesOut chan<- models.Batch,
	chJobErrorsOut chan<- JobError,
	wgActiveBatches *sync.WaitGroup,
) {
	definitiveErrors := 0

	for {
		if ctx.Err() != nil {
			return
		}

		select {
		case <-ctx.Done():
			return

		case err, ok := <-chErrorsIn:
			if !ok {
				return
			}

			if err.Batch.RetryCounter >= retryConfig.Attempts {
				wgActiveBatches.Done()
				definitiveErrors++
				jobError := JobError{
					ShouldCancelJob: false,
					Msg:             fmt.Sprintf("Batch %v reached max retries (%d)", err.Batch.Id, retryConfig.Attempts),
					Prev:            &err,
				}

				select {
				case chJobErrorsOut <- jobError:
				case <-ctx.Done():
					return
				}

				if maxChunkErrors > 0 && definitiveErrors >= maxChunkErrors {
					fatalError := JobError{
						ShouldCancelJob: true,
						Msg:             fmt.Sprintf("Chunk error limit reached (%d)", maxChunkErrors),
						Prev:            &err,
					}

					select {
					case chJobErrorsOut <- fatalError:
					case <-ctx.Done():
						return
					}
				}

				continue
			} else {
				jobError := JobError{
					ShouldCancelJob: false,
					Msg:             fmt.Sprintf("Temporal error in batch %v (retries: %d)", err.Batch.Id, err.Batch.RetryCounter),
					Prev:            &err,
				}

				select {
				case chJobErrorsOut <- jobError:
				case <-ctx.Done():
					return
				}
			}

			err.Batch.RetryCounter++
			delay := computeBackoffDelay(
				err.Batch.RetryCounter,
				retryConfig.BaseDelayMs,
				retryConfig.MaxDelayMs,
				retryConfig.MaxJitterMs,
			)

			requeueWithBackoff(ctx, delay, func() {
				select {
				case chBatchesOut <- err.Batch:
				case <-ctx.Done():
					return
				}
			})
		}
	}
}