// Package api implements the HTTP REST API for the GoClaw Gateway.
package api

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

	"git.softuniq.eu/UniqAI/GoClaw/gateway/config"
	"git.softuniq.eu/UniqAI/GoClaw/gateway/internal/db"
	dockerclient "git.softuniq.eu/UniqAI/GoClaw/gateway/internal/docker"
	"git.softuniq.eu/UniqAI/GoClaw/gateway/internal/llm"
	"git.softuniq.eu/UniqAI/GoClaw/gateway/internal/orchestrator"
	"git.softuniq.eu/UniqAI/GoClaw/gateway/internal/tools"
)

// Handler holds all dependencies for HTTP handlers.
type Handler struct {
	cfg    *config.Config
	llm    *llm.Client
	orch   *orchestrator.Orchestrator
	db     *db.DB
	docker *dockerclient.DockerClient
}

func NewHandler(cfg *config.Config, llmClient *llm.Client, orch *orchestrator.Orchestrator, database *db.DB) *Handler {
	return &Handler{
		cfg:    cfg,
		llm:    llmClient,
		orch:   orch,
		db:     database,
		docker: dockerclient.NewDockerClient(),
	}
}

// ─── Health ───────────────────────────────────────────────────────────────────

// GET /health
func (h *Handler) Health(w http.ResponseWriter, r *http.Request) {
	ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
	defer cancel()

	ollamaOK, latency, _ := h.llm.Health(ctx)

	respond(w, http.StatusOK, map[string]any{
		"status":    "ok",
		"service":   "goclaw-gateway",
		"version":   "1.0.0",
		"timestamp": time.Now().UTC().Format(time.RFC3339),
		"ollama": map[string]any{
			"connected": ollamaOK,
			"latencyMs": latency,
		},
	})
}

// ─── Orchestrator ─────────────────────────────────────────────────────────────

// POST /api/orchestrator/chat
func (h *Handler) OrchestratorChat(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Messages []orchestrator.Message `json:"messages"`
		Model    string                 `json:"model,omitempty"`
		MaxIter  int                    `json:"maxIter,omitempty"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		respondError(w, http.StatusBadRequest, "invalid request body: "+err.Error())
		return
	}
	if len(req.Messages) == 0 {
		respondError(w, http.StatusBadRequest, "messages array is required")
		return
	}

	log.Printf("[API] POST /api/orchestrator/chat — messages=%d model=%q", len(req.Messages), req.Model)

	ctx, cancel := context.WithTimeout(r.Context(), time.Duration(h.cfg.RequestTimeoutSecs)*time.Second)
	defer cancel()

	result := h.orch.Chat(ctx, req.Messages, req.Model, req.MaxIter)
	respond(w, http.StatusOK, result)
}

// GET /api/orchestrator/config
func (h *Handler) OrchestratorConfig(w http.ResponseWriter, r *http.Request) {
	cfg := h.orch.GetConfig()
	respond(w, http.StatusOK, map[string]any{
		"id":                  cfg.ID,
		"name":                cfg.Name,
		"model":               cfg.Model,
		"temperature":         cfg.Temperature,
		"maxTokens":           cfg.MaxTokens,
		"allowedTools":        cfg.AllowedTools,
		"systemPromptPreview": truncate(cfg.SystemPrompt, 200),
	})
}

// ─── Agents ───────────────────────────────────────────────────────────────────

// GET /api/agents
func (h *Handler) ListAgents(w http.ResponseWriter, r *http.Request) {
	if h.db == nil {
		respond(w, http.StatusOK, map[string]any{"agents": []any{}, "note": "DB not connected"})
		return
	}
	agents, err := h.db.ListAgents()
	if err != nil {
		respondError(w, http.StatusInternalServerError, "failed to list agents: "+err.Error())
		return
	}
	respond(w, http.StatusOK, map[string]any{"agents": agents, "count": len(agents)})
}

// GET /api/agents/{id}
func (h *Handler) GetAgent(w http.ResponseWriter, r *http.Request) {
	idStr := r.PathValue("id")
	id, err := strconv.Atoi(idStr)
	if err != nil {
		respondError(w, http.StatusBadRequest, "invalid agent id")
		return
	}
	if h.db == nil {
		respondError(w, http.StatusServiceUnavailable, "DB not connected")
		return
	}
	agent, err := h.db.GetAgentByID(id)
	if err != nil {
		respondError(w, http.StatusNotFound, "agent not found")
		return
	}
	respond(w, http.StatusOK, agent)
}

// ─── Models ───────────────────────────────────────────────────────────────────

// GET /api/models
func (h *Handler) ListModels(w http.ResponseWriter, r *http.Request) {
	ctx, cancel := context.WithTimeout(r.Context(), 15*time.Second)
	defer cancel()

	models, err := h.llm.ListModels(ctx)
	if err != nil {
		respondError(w, http.StatusBadGateway, "failed to fetch models: "+err.Error())
		return
	}
	respond(w, http.StatusOK, models)
}

// ─── Tools ────────────────────────────────────────────────────────────────────

// GET /api/tools
func (h *Handler) ListTools(w http.ResponseWriter, r *http.Request) {
	toolDefs := tools.OrchestratorTools()
	respond(w, http.StatusOK, map[string]any{
		"tools": toolDefs,
		"count": len(toolDefs),
	})
}

// POST /api/tools/execute
func (h *Handler) ExecuteTool(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Name      string         `json:"name"`
		Arguments map[string]any `json:"arguments"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		respondError(w, http.StatusBadRequest, "invalid request body: "+err.Error())
		return
	}
	if req.Name == "" {
		respondError(w, http.StatusBadRequest, "tool name is required")
		return
	}

	argsJSON, _ := json.Marshal(req.Arguments)
	executor := tools.NewExecutor("/", nil)
	result := executor.Execute(r.Context(), req.Name, string(argsJSON))
	respond(w, http.StatusOK, map[string]any{"result": result})
}

// ─── Nodes ────────────────────────────────────────────────────────────────────

// NodeInfo is the unified node response sent to the frontend.
type NodeInfo struct {
	ID             string            `json:"id"`
	Hostname       string            `json:"hostname"`
	Role           string            `json:"role"`
	Status         string            `json:"status"`
	Availability   string            `json:"availability"`
	IP             string            `json:"ip"`
	OS             string            `json:"os"`
	Arch           string            `json:"arch"`
	CPUCores       int               `json:"cpuCores"`
	MemTotalMB     int64             `json:"memTotalMB"`
	DockerVersion  string            `json:"dockerVersion"`
	IsLeader       bool              `json:"isLeader"`
	ManagerAddr    string            `json:"managerAddr,omitempty"`
	Labels         map[string]string `json:"labels"`
	UpdatedAt      string            `json:"updatedAt"`
}

// ContainerInfo is a slim container summary per node.
type ContainerInfo struct {
	ID     string `json:"id"`
	Name   string `json:"name"`
	Image  string `json:"image"`
	State  string `json:"state"`
	Status string `json:"status"`
}

// GET /api/nodes
func (h *Handler) ListNodes(w http.ResponseWriter, r *http.Request) {
	// Check if Swarm is active
	swarmActive := h.docker.IsSwarmActive()

	if swarmActive {
		// Return real Swarm nodes
		nodes, err := h.docker.ListNodes()
		if err != nil {
			log.Printf("[API] ListNodes swarm error: %v — falling back to local info", err)
			h.listLocalNode(w, r)
			return
		}

		result := make([]NodeInfo, 0, len(nodes))
		for _, n := range nodes {
			info := NodeInfo{
				ID:            n.ID[:12],
				Hostname:      n.Description.Hostname,
				Role:          n.Spec.Role,
				Status:        n.Status.State,
				Availability:  n.Spec.Availability,
				IP:            n.Status.Addr,
				OS:            n.Description.Platform.OS,
				Arch:          n.Description.Platform.Architecture,
				CPUCores:      int(n.Description.Resources.NanoCPUs / 1e9),
				MemTotalMB:    n.Description.Resources.MemoryBytes / (1024 * 1024),
				DockerVersion: n.Description.Engine.EngineVersion,
				Labels:        n.Spec.Labels,
				UpdatedAt:     n.UpdatedAt.UTC().Format(time.RFC3339),
			}
			if n.ManagerStatus != nil {
				info.IsLeader = n.ManagerStatus.Leader
				info.ManagerAddr = n.ManagerStatus.Addr
			}
			if info.Labels == nil {
				info.Labels = map[string]string{}
			}
			result = append(result, info)
		}

		swarmInfo, _ := h.docker.GetSwarmInfo()
		managers, totalNodes := 0, len(result)
		if swarmInfo != nil {
			managers = swarmInfo.Swarm.Managers
			totalNodes = swarmInfo.Swarm.Nodes
		}

		respond(w, http.StatusOK, map[string]any{
			"nodes":       result,
			"count":       len(result),
			"swarmActive": true,
			"managers":    managers,
			"totalNodes":  totalNodes,
			"fetchedAt":   time.Now().UTC().Format(time.RFC3339),
		})
		return
	}

	// Swarm not active — return local Docker host info
	h.listLocalNode(w, r)
}

// listLocalNode returns info about the current Docker host as a single "node".
func (h *Handler) listLocalNode(w http.ResponseWriter, r *http.Request) {
	info, err := h.docker.GetSwarmInfo()
	hostname := "localhost"
	if err == nil && info != nil {
		_ = info // use for future enrichment
	}

	// Get containers running on this host
	containers, _ := h.docker.ListContainers()
	containerInfos := make([]ContainerInfo, 0, len(containers))
	for _, c := range containers {
		name := c.ID[:12]
		if len(c.Names) > 0 {
			name = c.Names[0]
			if len(name) > 0 && name[0] == '/' {
				name = name[1:]
			}
		}
		containerInfos = append(containerInfos, ContainerInfo{
			ID:     c.ID[:12],
			Name:   name,
			Image:  c.Image,
			State:  c.State,
			Status: c.Status,
		})
	}

	node := NodeInfo{
		ID:           "local-01",
		Hostname:     hostname,
		Role:         "standalone",
		Status:       "ready",
		Availability: "active",
		IP:           "127.0.0.1",
		DockerVersion: "unknown",
		Labels:       map[string]string{},
		UpdatedAt:    time.Now().UTC().Format(time.RFC3339),
	}

	respond(w, http.StatusOK, map[string]any{
		"nodes":       []NodeInfo{node},
		"count":       1,
		"swarmActive": false,
		"containers":  containerInfos,
		"fetchedAt":   time.Now().UTC().Format(time.RFC3339),
	})
}

// GET /api/nodes/stats
// Returns live container stats (CPU%, RAM) for containers on this host.
func (h *Handler) NodeStats(w http.ResponseWriter, r *http.Request) {
	containers, err := h.docker.ListContainers()
	if err != nil {
		respondError(w, http.StatusInternalServerError, "failed to list containers: "+err.Error())
		return
	}

	type ContainerStat struct {
		ID       string  `json:"id"`
		Name     string  `json:"name"`
		CPUPct   float64 `json:"cpuPct"`
		MemUseMB float64 `json:"memUseMB"`
		MemLimMB float64 `json:"memLimMB"`
		MemPct   float64 `json:"memPct"`
	}

	stats := make([]ContainerStat, 0, len(containers))
	for _, c := range containers {
		s, err := h.docker.GetContainerStats(c.ID)
		if err != nil {
			continue
		}
		name := c.ID[:12]
		if len(c.Names) > 0 {
			name = c.Names[0]
			if len(name) > 0 && name[0] == '/' {
				name = name[1:]
			}
		}
		cpuPct := dockerclient.CalcCPUPercent(s)
		memUse := float64(s.MemoryStats.Usage) / (1024 * 1024)
		memLim := float64(s.MemoryStats.Limit) / (1024 * 1024)
		memPct := 0.0
		if memLim > 0 {
			memPct = (memUse / memLim) * 100
		}
		stats = append(stats, ContainerStat{
			ID:       c.ID[:12],
			Name:     name,
			CPUPct:   round2(cpuPct),
			MemUseMB: round2(memUse),
			MemLimMB: round2(memLim),
			MemPct:   round2(memPct),
		})
	}

	respond(w, http.StatusOK, map[string]any{
		"stats":     stats,
		"count":     len(stats),
		"fetchedAt": time.Now().UTC().Format(time.RFC3339),
	})
}

// ─── Helpers ──────────────────────────────────────────────────────────────────

func respond(w http.ResponseWriter, status int, data any) {
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("Access-Control-Allow-Origin", "*")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(data)
}

func respondError(w http.ResponseWriter, status int, msg string) {
	respond(w, status, map[string]any{"error": msg})
}

func truncate(s string, n int) string {
	if len(s) <= n {
		return s
	}
	return s[:n] + "..."
}

func round2(f float64) float64 {
	return float64(int(f*100)) / 100
}

func init() {
	_ = fmt.Sprintf // suppress unused import
}