package forge

import (
	"errors"
	"fmt"
	"os"
	"os/exec"
	"strings"

	"github.com/cruldra/superpowers-vscode/cli/internal/repo"
	"github.com/cruldra/superpowers-vscode/cli/internal/tea"
)

// Env is where [Open] gets credentials from; tests swap in canned answers, real runs use [SystemEnv].
type Env struct {
	// GitHubToken returns the token the GitHub CLI holds for `host`.
	GitHubToken func(host string) (string, error)
	// TeaLogin returns the tea login whose URL points at `host`, or `nil` when there is none.
	TeaLogin func(host string) (*tea.TeaLogin, error)
	// Getenv reads an environment variable.
	Getenv func(key string) string
}

// SystemEnv reads credentials from this machine: `gh auth token`, the tea config file and the process environment.
func SystemEnv() Env {
	return Env{
		GitHubToken: ghAuthToken,
		TeaLogin: func(host string) (*tea.TeaLogin, error) {
			path, err := tea.DefaultConfigPath()
			if err != nil {
				return nil, err
			}
			return tea.LoginForHost(path, host)
		},
		Getenv: os.Getenv,
	}
}

// ghAuthToken asks the GitHub CLI for the token it stores for `host`.
func ghAuthToken(host string) (string, error) {
	out, err := exec.Command("gh", "auth", "token", "--hostname", host).Output()
	if err != nil {
		var exitErr *exec.ExitError
		if errors.As(err, &exitErr) && len(exitErr.Stderr) > 0 {
			return "", fmt.Errorf("gh auth token --hostname %s 失败: %w: %s", host, err, strings.TrimSpace(string(exitErr.Stderr)))
		}
		return "", fmt.Errorf("gh auth token --hostname %s 失败: %w", host, err)
	}
	return string(out), nil
}

// Open connects to the repo at `o` on the forge its host names, picking credentials the way that forge expects.
//
// GitHub takes the token from `gh auth token`. Gitea needs a [tea.TeaLogin] for the same host and uses its URL as the API
// root and its token; `GITEA_TOKEN` only fills in when that login has no token, so the variable never reaches a host the
// user has not logged in to with tea.
func Open(o repo.Origin, env Env) (Forge, error) {
	if KindForHost(o.Host) == KindGitHub {
		token, err := env.GitHubToken(o.Host)
		if err != nil {
			return nil, fmt.Errorf("取 GitHub token 失败，请先运行 `gh auth login`: %w", err)
		}
		token = strings.TrimSpace(token)
		if token == "" {
			return nil, fmt.Errorf("gh 没有 %s 的 token，请先运行 `gh auth login`", o.Host)
		}
		return NewGitHub(GitHubAPIBaseURL, token, o.Owner, o.Repo), nil
	}
	login, err := env.TeaLogin(o.Host)
	if err != nil {
		return nil, err
	}
	if login == nil {
		return nil, fmt.Errorf("tea config 里没有 %s 的 login，spx 不会把 Gitea token 发给 tea 没登录过的 host；请先运行 `tea login add` 登录这个 host", o.Host)
	}
	token := login.Token
	if token == "" {
		token = env.Getenv("GITEA_TOKEN")
	}
	if token == "" {
		return nil, fmt.Errorf("tea config 里 %s 的 login %q 没有 token，GITEA_TOKEN 也没设置；请重新运行 `tea login add` 或设置 GITEA_TOKEN", o.Host, login.Name)
	}
	return NewGitea(login.URL, token, o.Owner, o.Repo), nil
}