package deploy

import (
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"
)

// SSMDocumentFetchPlan mirrors the SSM run-command curl shard order.
type SSMDocumentFetchPlan struct {
	ManifestURL string
	ShardURLs   []string
	FallbackURL string
}

var ssmDocumentHTTPGet = defaultSSMDocumentHTTPGet

func defaultSSMDocumentHTTPGet(url string) ([]byte, error) {
	url = strings.TrimSpace(url)
	if url == "" {
		return nil, fmt.Errorf("empty url")
	}
	client := &http.Client{Timeout: 15 * time.Second}
	resp, err := client.Get(url)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("ssm fetch HTTP %d", resp.StatusCode)
	}
	return io.ReadAll(io.LimitReader(resp.Body, 8<<20))
}

func SetSSMDocumentHTTPGetForTest(fn func(string) ([]byte, error)) {
	if fn == nil {
		ssmDocumentHTTPGet = defaultSSMDocumentHTTPGet
		return
	}
	ssmDocumentHTTPGet = fn
}

// RunSSMDocumentFetch executes manifest → shards → fallback in order (mockable).
func RunSSMDocumentFetch(plan SSMDocumentFetchPlan) ([]string, error) {
	var fetched []string
	fetch := func(url string) error {
		url = strings.TrimSpace(url)
		if url == "" {
			return nil
		}
		if _, err := ssmDocumentHTTPGet(url); err != nil {
			return err
		}
		fetched = append(fetched, url)
		return nil
	}
	if err := fetch(plan.ManifestURL); err != nil {
		return fetched, fmt.Errorf("manifest: %w", err)
	}
	for _, u := range plan.ShardURLs {
		if err := fetch(u); err != nil {
			return fetched, fmt.Errorf("shard: %w", err)
		}
	}
	if err := fetch(plan.FallbackURL); err != nil {
		return fetched, fmt.Errorf("fallback: %w", err)
	}
	return fetched, nil
}