package gitea

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"
)

// Repo represents a Gitea repository.
type Repo struct {
	ID            int64  `json:"id"`
	FullName      string `json:"full_name"`
	CloneURL      string `json:"clone_url"`
	DefaultBranch string `json:"default_branch"`
	Empty         bool   `json:"empty"`
	Archived      bool   `json:"archived"`
	UpdatedAt     string `json:"updated_at"`
}

// Client is a Gitea API client.
type Client struct {
	baseURL    string
	token      string
	httpClient *http.Client
}

// NewClient creates a new Gitea API client.
func NewClient(baseURL, token string) *Client {
	return &Client{
		baseURL: baseURL,
		token:   token,
		httpClient: &http.Client{
			Timeout: 30 * time.Second,
		},
	}
}

// ListAllRepos returns all repositories accessible to the authenticated user.
// It paginates through all results automatically.
func (c *Client) ListAllRepos() ([]Repo, error) {
	var allRepos []Repo
	page := 1
	limit := 50

	for {
		url := fmt.Sprintf("%s/api/v1/repos/search?page=%d&limit=%d",
			c.baseURL, page, limit)

		req, err := http.NewRequest("GET", url, nil)
		if err != nil {
			return nil, fmt.Errorf("creating request: %w", err)
		}
		req.Header.Set("Accept", "application/json")
		req.Header.Set("Authorization", "token "+c.token)

		resp, err := c.httpClient.Do(req)
		if err != nil {
			return nil, fmt.Errorf("fetching repos page %d: %w", page, err)
		}

		if resp.StatusCode != http.StatusOK {
			body, _ := io.ReadAll(resp.Body)
			resp.Body.Close()
			return nil, fmt.Errorf("gitea API returned %d: %s", resp.StatusCode, string(body))
		}

		var result struct {
			Data []Repo `json:"data"`
		}
		if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
			resp.Body.Close()
			return nil, fmt.Errorf("decoding response: %w", err)
		}
		resp.Body.Close()

		if len(result.Data) == 0 {
			break
		}

		allRepos = append(allRepos, result.Data...)

		if len(result.Data) < limit {
			break
		}
		page++
	}

	// Filter out empty repos
	filtered := make([]Repo, 0, len(allRepos))
	for _, r := range allRepos {
		if !r.Empty {
			filtered = append(filtered, r)
		}
	}

	return filtered, nil
}

// GetRepo returns a single repository by owner/name.
func (c *Client) GetRepo(fullName string) (*Repo, error) {
	url := fmt.Sprintf("%s/api/v1/repos/%s", c.baseURL, fullName)

	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, fmt.Errorf("creating request: %w", err)
	}
	req.Header.Set("Accept", "application/json")
	req.Header.Set("Authorization", "token "+c.token)

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("fetching repo %s: %w", fullName, err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("gitea API returned %d: %s", resp.StatusCode, string(body))
	}

	var repo Repo
	if err := json.NewDecoder(resp.Body).Decode(&repo); err != nil {
		return nil, fmt.Errorf("decoding response: %w", err)
	}

	return &repo, nil
}

// AuthenticatedCloneURL returns the clone URL with the token embedded for private repos.
func (c *Client) AuthenticatedCloneURL(repo Repo) string {
	// Insert token into https URL: https://token@host/path.git
	if len(c.baseURL) > 8 {
		return fmt.Sprintf("%s://%s@%s",
			c.baseURL[:5], // "https"
			c.token,
			repo.CloneURL[8:]) // strip "https://"
	}
	return repo.CloneURL
}