// Package tea reads the tea CLI config to find the Gitea login, and its token, for a given host.
//
// tea config typically lives at $HOME/.config/tea/config.yml. Older versions
// of tea (<v0.10) stored the token inline in the YAML; newer versions move
// tokens into a system keyring and only keep metadata in the file.
//
// We support the inline form here. If the token field is missing, callers
// fall back to the GITEA_TOKEN environment variable.
package tea

import (
	"errors"
	"fmt"
	"io/fs"
	"net/url"
	"os"
	"path/filepath"
	"strings"

	"gopkg.in/yaml.v3"
)

// TeaLogin represents a single login entry in tea config.yml.
type TeaLogin struct {
	Name    string `yaml:"name"`
	URL     string `yaml:"url"`
	Token   string `yaml:"token"`
	Default bool   `yaml:"default"`
}

// TeaConfig is the top-level structure of tea config.yml.
type TeaConfig struct {
	Logins []TeaLogin `yaml:"logins"`
}

// DefaultConfigPath returns the conventional path to tea's config.yml.
func DefaultConfigPath() (string, error) {
	home, err := os.UserHomeDir()
	if err != nil {
		return "", fmt.Errorf("解析 home 目录失败: %w", err)
	}
	return filepath.Join(home, ".config", "tea", "config.yml"), nil
}

// load reads and parses the tea config file at the given path.
func load(path string) (*TeaConfig, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("读取 tea config %s 失败: %w", path, err)
	}
	var cfg TeaConfig
	if err := yaml.Unmarshal(data, &cfg); err != nil {
		return nil, fmt.Errorf("解析 tea config %s 失败: %w", path, err)
	}
	return &cfg, nil
}

// LoginForHost returns the login in the tea config at `path` whose URL points at `host`, or `nil` when none does.
//
// Hosts are compared by hostname only, ignoring case, scheme, port and trailing slashes, so the host read from a git
// SSH remote still finds the login saved with the forge's web URL. When several logins point at `host`, the one marked
// `default` wins, because that is the identity the user picked; otherwise the first. A missing config file just means
// there is no login, so it returns `nil` rather than an error.
func LoginForHost(path, host string) (*TeaLogin, error) {
	cfg, err := load(path)
	if errors.Is(err, fs.ErrNotExist) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	want := strings.ToLower(host)
	var first *TeaLogin
	for i := range cfg.Logins {
		u, perr := url.Parse(strings.TrimSpace(cfg.Logins[i].URL))
		if perr != nil || strings.ToLower(u.Hostname()) != want {
			continue
		}
		if cfg.Logins[i].Default {
			return &cfg.Logins[i], nil
		}
		if first == nil {
			first = &cfg.Logins[i]
		}
	}
	return first, nil
}