package config

import (
	"fmt"
	"os"
	"strings"

	"gopkg.in/yaml.v3"
)

// TeaLogin is one entry from a tea config.yml `logins:` list. Only the fields
// teabot needs are modelled; unknown keys are ignored by the YAML decoder.
type TeaLogin struct {
	Name    string `yaml:"name"`
	URL     string `yaml:"url"`
	Token   string `yaml:"token"`
	Default bool   `yaml:"default"`
	User    string `yaml:"user"`
}

// teaConfigFile mirrors the top level of tea's config.yml.
type teaConfigFile struct {
	Logins []TeaLogin `yaml:"logins"`
}

// ParseTeaConfig reads a tea config.yml and returns the login teabot should use.
// It prefers a login whose URL matches wantURL, then the default login, then the
// first login. This is the same file format as ~/.config/tea/config.yml.
func ParseTeaConfig(path, wantURL string) (TeaLogin, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		return TeaLogin{}, fmt.Errorf("reading tea config %s: %w", path, err)
	}
	var f teaConfigFile
	if err := yaml.Unmarshal(data, &f); err != nil {
		return TeaLogin{}, fmt.Errorf("parsing tea config %s: %w", path, err)
	}
	if len(f.Logins) == 0 {
		return TeaLogin{}, fmt.Errorf("tea config %s has no logins", path)
	}

	want := strings.TrimRight(wantURL, "/")
	var byURL, byDefault *TeaLogin
	for i := range f.Logins {
		l := &f.Logins[i]
		if want != "" && strings.TrimRight(l.URL, "/") == want && byURL == nil {
			byURL = l
		}
		if l.Default && byDefault == nil {
			byDefault = l
		}
	}
	switch {
	case byURL != nil:
		return *byURL, nil
	case byDefault != nil:
		return *byDefault, nil
	default:
		return f.Logins[0], nil
	}
}