// Package woodpecker activates a repository in Woodpecker CI by its forge
// remote id.
package woodpecker

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

// Client talks to one Woodpecker server.
type Client struct {
	BaseURL string
	Token   string
	HTTP    *http.Client
}

// New builds a Client with a bounded HTTP client.
func New(baseURL, token string) *Client {
	return &Client{
		BaseURL: strings.TrimSuffix(baseURL, "/"),
		Token:   token,
		HTTP:    &http.Client{Timeout: 30 * time.Second},
	}
}

// Repo is the subset of a Woodpecker repository record that matters here.
type Repo struct {
	ID       int64  `json:"id"`
	FullName string `json:"full_name"`
	Active   bool   `json:"active"`
}

// Enable activates the repository identified by its forge remote id. An
// already-active repository answers 409, which counts as success.
func (c *Client) Enable(ctx context.Context, forgeRemoteID int64) (Repo, error) {
	var out Repo
	path := "/api/repos?forge_remote_id=" + strconv.FormatInt(forgeRemoteID, 10)
	err := c.do(ctx, http.MethodPost, path, &out)
	var se *StatusError
	if errors.As(err, &se) && se.Status == http.StatusConflict {
		return out, nil
	}
	return out, err
}

// Lookup fetches a repository by "owner/name", used to confirm activation.
func (c *Client) Lookup(ctx context.Context, fullName string) (Repo, error) {
	var out Repo
	err := c.do(ctx, http.MethodGet, "/api/repos/lookup/"+fullName, &out)
	return out, err
}

// StatusError carries a non-2xx response.
type StatusError struct {
	Status int
	Path   string
	Body   string
}

func (e *StatusError) Error() string {
	msg := fmt.Sprintf("woodpecker %s: status %d", e.Path, e.Status)
	if e.Body != "" {
		msg += ": " + e.Body
	}
	return msg
}

func (c *Client) do(ctx context.Context, method, path string, out any) error {
	req, err := http.NewRequestWithContext(ctx, method, c.BaseURL+path, nil)
	if err != nil {
		return err
	}
	req.Header.Set("Accept", "application/json")
	if c.Token != "" {
		req.Header.Set("Authorization", "Bearer "+c.Token)
	}
	client := c.HTTP
	if client == nil {
		client = http.DefaultClient
	}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode < 200 || resp.StatusCode > 299 {
		snippet, _ := io.ReadAll(io.LimitReader(resp.Body, 512))
		return &StatusError{Status: resp.StatusCode, Path: path, Body: strings.TrimSpace(string(snippet))}
	}
	if out == nil {
		_, _ = io.Copy(io.Discard, resp.Body)
		return nil
	}
	return json.NewDecoder(resp.Body).Decode(out)
}