package dnscfg

import (
	"fmt"
	"strings"
)

func NormalizeUpstreams(cfg Upstreams, defaults Upstreams, normalizeUpstream func(raw string, defaultPort string) string) Upstreams {
	if normalizeUpstream != nil {
		cfg.Default1 = normalizeUpstream(cfg.Default1, "53")
		cfg.Default2 = normalizeUpstream(cfg.Default2, "53")
		cfg.Meta1 = normalizeUpstream(cfg.Meta1, "53")
		cfg.Meta2 = normalizeUpstream(cfg.Meta2, "53")
	}

	if strings.TrimSpace(cfg.Default1) == "" {
		cfg.Default1 = defaults.Default1
	}
	if strings.TrimSpace(cfg.Default2) == "" {
		cfg.Default2 = defaults.Default2
	}
	if strings.TrimSpace(cfg.Meta1) == "" {
		cfg.Meta1 = defaults.Meta1
	}
	if strings.TrimSpace(cfg.Meta2) == "" {
		cfg.Meta2 = defaults.Meta2
	}
	return cfg
}

func ParseUpstreamsConf(content string, defaults Upstreams, normalizeUpstream func(raw string, defaultPort string) string) Upstreams {
	cfg := defaults
	for _, ln := range strings.Split(content, "\n") {
		s := strings.TrimSpace(ln)
		if s == "" || strings.HasPrefix(s, "#") {
			continue
		}
		parts := strings.Fields(s)
		if len(parts) < 2 {
			continue
		}
		key := strings.ToLower(strings.TrimSpace(parts[0]))
		vals := parts[1:]
		switch key {
		case "default":
			if len(vals) > 0 {
				cfg.Default1 = vals[0]
			}
			if len(vals) > 1 {
				cfg.Default2 = vals[1]
			}
		case "meta":
			if len(vals) > 0 {
				cfg.Meta1 = vals[0]
			}
			if len(vals) > 1 {
				cfg.Meta2 = vals[1]
			}
		}
	}
	return NormalizeUpstreams(cfg, defaults, normalizeUpstream)
}

func RenderUpstreamsConf(cfg Upstreams) string {
	return fmt.Sprintf(
		"default %s %s\nmeta %s %s\n",
		cfg.Default1, cfg.Default2, cfg.Meta1, cfg.Meta2,
	)
}