// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package services

import (
	"context"
	"net/http"

	gitea "gitea.dev/sdk"
	"gitea.dev/tea/internal/transport"
)

// lookup repeats a read on the instance of the failed request apiErr, with its credential, to
// explain the failure. It returns the response status, or 0 when apiErr was not recorded from a
// request, the read got no response, or a successful response did not decode.
func lookup[T any](ctx context.Context, apiErr *transport.APIError, repository string, op repoOperation[T]) (T, int) {
	var zero T
	httpClient := apiErr.LookupClient()
	if httpClient == nil {
		return zero, 0
	}
	owner, repo, err := splitRepository(repository)
	if err != nil {
		return zero, 0
	}
	sdk, err := gitea.NewClient(apiErr.Instance, gitea.SetHTTPClient(httpClient), gitea.SetGiteaVersion(""))
	if err != nil {
		return zero, 0
	}
	result, resp, err := op(ctx, sdk, owner, repo)
	switch {
	case resp == nil || resp.Response == nil:
		return zero, 0
	case err == nil:
		return result, resp.StatusCode
	case resp.StatusCode >= 200 && resp.StatusCode < 300:
		return zero, 0
	}
	return zero, resp.StatusCode
}

// RepositoryState holds the repository facts that explain a failed request on it.
type RepositoryState struct {
	Empty, Issues, PullRequests, Wiki, Releases, Actions, Projects bool
}

// LookupRepository reads the state of repo for the failed request apiErr; see lookup for the status.
func LookupRepository(ctx context.Context, apiErr *transport.APIError, repo string) (RepositoryState, int) {
	item, status := lookup(ctx, apiErr, repo, func(ctx context.Context, c *gitea.Client, owner, name string) (*gitea.Repository, *gitea.Response, error) {
		return c.Repositories.GetRepo(ctx, owner, name)
	})
	if item == nil {
		return RepositoryState{}, status
	}
	return RepositoryState{
		Empty: item.Empty, Issues: item.HasIssues, PullRequests: item.HasPullRequests, Wiki: item.HasWiki,
		Releases: item.HasReleases, Actions: item.HasActions, Projects: item.HasProjects,
	}, status
}

// LookupIsIssue reports whether number names an issue rather than a pull request in repo, for the
// failed request apiErr.
func LookupIsIssue(ctx context.Context, apiErr *transport.APIError, repo string, number int64) bool {
	item, status := lookup(ctx, apiErr, repo, func(ctx context.Context, c *gitea.Client, owner, name string) (*gitea.Issue, *gitea.Response, error) {
		return c.Issues.GetIssue(ctx, owner, name, number)
	})
	return status == http.StatusOK && item != nil && item.PullRequest == nil
}

// LookupPullURL returns the web URL of the pull request from head into base in repo, for the failed
// request apiErr, or "".
func LookupPullURL(ctx context.Context, apiErr *transport.APIError, repo, base, head string) string {
	item, status := lookup(ctx, apiErr, repo, func(ctx context.Context, c *gitea.Client, owner, name string) (*gitea.PullRequest, *gitea.Response, error) {
		return c.PullRequests.GetPullRequestByBaseHead(ctx, owner, name, base, head)
	})
	if status != http.StatusOK || item == nil {
		return ""
	}
	return item.HTMLURL
}