package gitea

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"
)

var ErrTokenNotConfigured = errors.New("gitea API token is not configured")

type Repository struct {
	ID            int64  `json:"id"`
	Owner         Owner  `json:"owner"`
	Name          string `json:"name"`
	FullName      string `json:"full_name"`
	CloneURL      string `json:"clone_url"`
	DefaultBranch string `json:"default_branch"`
}

type Owner struct {
	Login    string `json:"login"`
	Username string `json:"username"`
}

func (r Repository) OwnerName() string {
	if r.Owner.Login != "" {
		return r.Owner.Login
	}
	return r.Owner.Username
}

type Client struct {
	baseURL *url.URL
	token   string
	http    *http.Client
}

func NewClient(baseURL, token string) (*Client, error) {
	u, err := url.Parse(strings.TrimRight(baseURL, "/"))
	if err != nil || u.Scheme == "" || u.Host == "" {
		return nil, fmt.Errorf("invalid GITEA_BASE_URL %q", baseURL)
	}
	return &Client{baseURL: u, token: token, http: &http.Client{Timeout: 10 * time.Second}}, nil
}

func (c *Client) Repository(ctx context.Context, owner, name string) (Repository, error) {
	if c.token == "" {
		return Repository{}, ErrTokenNotConfigured
	}
	u := c.baseURL.JoinPath("api", "v1", "repos", owner, name)
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
	if err != nil {
		return Repository{}, err
	}
	req.Header.Set("Authorization", "token "+c.token)
	req.Header.Set("Accept", "application/json")

	resp, err := c.http.Do(req)
	if err != nil {
		return Repository{}, fmt.Errorf("request repository: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return Repository{}, fmt.Errorf("gitea repository lookup returned %s", resp.Status)
	}

	var repo Repository
	if err := json.NewDecoder(resp.Body).Decode(&repo); err != nil {
		return Repository{}, fmt.Errorf("decode repository: %w", err)
	}
	if repo.ID <= 0 || repo.OwnerName() == "" || repo.Name == "" {
		return Repository{}, errors.New("gitea returned an incomplete repository")
	}
	return repo, nil
}