package nodedispatch

import (
	"bytes"
	"context"
	"crypto/tls"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"
	"time"

	"evobgp/internal/store"
)

// Result is one speaker dispatch outcome for job meta.
type Result struct {
	SpeakerID         string `json:"speaker_id"`
	Endpoint          string `json:"endpoint,omitempty"`
	Status            string `json:"status"`
	AppliedRevisionID string `json:"applied_revision_id,omitempty"`
	Error             string `json:"error,omitempty"`
}

// Options configures Panel→Node HTTP dispatch.
type Options struct {
	HTTPClient   *http.Client
	Timeout      time.Duration
	MaxRetries   int
	InsecureTLS  bool
	RevisionID   string
}

func (o Options) client() *http.Client {
	if o.HTTPClient != nil {
		return o.HTTPClient
	}
	timeout := o.Timeout
	if timeout <= 0 {
		timeout = 30 * time.Second
	}
	tr := http.DefaultTransport.(*http.Transport).Clone()
	if o.InsecureTLS || strings.TrimSpace(os.Getenv("EVOBGP_NODE_DISPATCH_INSECURE_TLS")) == "1" {
		tr.TLSClientConfig = &tls.Config{InsecureSkipVerify: true} //nolint:gosec // dev/lab only via env
	}
	return &http.Client{Timeout: timeout, Transport: tr}
}

func (o Options) retries() int {
	if o.MaxRetries > 0 {
		return o.MaxRetries
	}
	return 3
}

// Enabled reports whether remote dispatch is turned on (EVOBGP_NODE_DISPATCH_ENABLED=1).
func Enabled() bool {
	return strings.TrimSpace(os.Getenv("EVOBGP_NODE_DISPATCH_ENABLED")) == "1"
}

// WakeSpeaker POSTs /v1/agent/sync to a replica agent (HTTPS via Traefik).
func WakeSpeaker(ctx context.Context, sp *store.Speaker, opts Options) Result {
	res := Result{SpeakerID: sp.ID}
	if sp == nil {
		res.Status = "error"
		res.Error = "nil speaker"
		return res
	}
	meta := store.ParseSpeakerMeta(sp.MetaJSON)
	url := store.AgentSyncURL(meta)
	if url == "" {
		res.Status = "skipped"
		res.Error = "agent_domain or agent_secret not configured"
		return res
	}
	res.Endpoint = url
	secret := strings.TrimSpace(meta.AgentSecret)
	if secret == "" {
		res.Status = "skipped"
		res.Error = "agent_secret missing"
		return res
	}

	body := map[string]string{}
	if rid := strings.TrimSpace(opts.RevisionID); rid != "" {
		body["revision_id"] = rid
	}
	raw, _ := json.Marshal(body)

	var lastErr error
	client := opts.client()
	for attempt := 0; attempt < opts.retries(); attempt++ {
		if attempt > 0 {
			select {
			case <-ctx.Done():
				res.Status = "error"
				res.Error = ctx.Err().Error()
				return res
			case <-time.After(time.Duration(attempt) * 2 * time.Second):
			}
		}
		req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(raw))
		if err != nil {
			lastErr = err
			continue
		}
		req.Header.Set("Authorization", "Bearer "+secret)
		req.Header.Set("Content-Type", "application/json")
		resp, err := client.Do(req)
		if err != nil {
			lastErr = err
			continue
		}
		b, _ := io.ReadAll(resp.Body)
		_ = resp.Body.Close()
		if resp.StatusCode >= 200 && resp.StatusCode < 300 {
			var out struct {
				AppliedRevisionID string `json:"applied_revision_id"`
			}
			_ = json.Unmarshal(b, &out)
			res.Status = "ok"
			res.AppliedRevisionID = strings.TrimSpace(out.AppliedRevisionID)
			if res.AppliedRevisionID == "" {
				res.AppliedRevisionID = strings.TrimSpace(opts.RevisionID)
			}
			return res
		}
		lastErr = fmt.Errorf("HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(b)))
	}
	res.Status = "error"
	if lastErr != nil {
		res.Error = lastErr.Error()
	}
	return res
}

// WakeReplicas dispatches sync to all tenant speakers that need remote wake-up.
func WakeReplicas(ctx context.Context, st store.Backend, tenantID, revisionID string, opts Options) []Result {
	if st == nil {
		return nil
	}
	opts.RevisionID = revisionID
	var out []Result
	for _, sp := range st.ListSpeakersForTenant(tenantID) {
		if sp == nil {
			continue
		}
		meta := store.ParseSpeakerMeta(sp.MetaJSON)
		if !store.SpeakerNeedsRemoteDispatch(sp.Role, meta) {
			continue
		}
		out = append(out, WakeSpeaker(ctx, sp, opts))
	}
	return out
}

// CheckHealth GETs /v1/agent/health for UI Connected/Offline status.
func CheckHealth(ctx context.Context, sp *store.Speaker, opts Options) (ok bool, detail string) {
	if sp == nil {
		return false, "nil speaker"
	}
	meta := store.ParseSpeakerMeta(sp.MetaJSON)
	url := store.AgentHealthURL(meta)
	if url == "" {
		return false, "agent_domain not configured"
	}
	secret := strings.TrimSpace(meta.AgentSecret)
	if secret == "" {
		return false, "agent_secret missing"
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return false, err.Error()
	}
	req.Header.Set("Authorization", "Bearer "+secret)
	resp, err := opts.client().Do(req)
	if err != nil {
		return false, err.Error()
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
		return true, "connected"
	}
	b, _ := io.ReadAll(resp.Body)
	return false, fmt.Sprintf("HTTP %d: %s", resp.StatusCode, strings.TrimSpace(string(b)))
}