package handler

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	"github.com/go-chi/chi/v5"
	db "github.com/multica-ai/multica/server/pkg/db/generated"
	"github.com/multica-ai/multica/server/pkg/protocol"
)

// ---------------------------------------------------------------------------
// Daemon Registration & Heartbeat
// ---------------------------------------------------------------------------

type DaemonRegisterRequest struct {
	WorkspaceID string `json:"workspace_id"`
	DaemonID    string `json:"daemon_id"`
	DeviceName  string `json:"device_name"`
	Runtimes    []struct {
		Name    string `json:"name"`
		Type    string `json:"type"`
		Version string `json:"version"`
		Status  string `json:"status"`
	} `json:"runtimes"`
}

func (h *Handler) DaemonRegister(w http.ResponseWriter, r *http.Request) {
	var req DaemonRegisterRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	req.WorkspaceID = strings.TrimSpace(req.WorkspaceID)
	req.DaemonID = strings.TrimSpace(req.DaemonID)
	req.DeviceName = strings.TrimSpace(req.DeviceName)

	if req.DaemonID == "" {
		writeError(w, http.StatusBadRequest, "daemon_id is required")
		return
	}
	if req.WorkspaceID == "" {
		writeError(w, http.StatusBadRequest, "workspace_id is required")
		return
	}
	if len(req.Runtimes) == 0 {
		writeError(w, http.StatusBadRequest, "at least one runtime is required")
		return
	}
	if _, err := h.Queries.GetWorkspace(r.Context(), parseUUID(req.WorkspaceID)); err != nil {
		writeError(w, http.StatusNotFound, "workspace not found")
		return
	}

	resp := make([]AgentRuntimeResponse, 0, len(req.Runtimes))
	for _, runtime := range req.Runtimes {
		provider := strings.TrimSpace(runtime.Type)
		if provider == "" {
			provider = "unknown"
		}
		name := strings.TrimSpace(runtime.Name)
		if name == "" {
			name = provider
			if req.DeviceName != "" {
				name = fmt.Sprintf("%s (%s)", provider, req.DeviceName)
			}
		}
		deviceInfo := strings.TrimSpace(req.DeviceName)
		if runtime.Version != "" && deviceInfo != "" {
			deviceInfo = fmt.Sprintf("%s · %s", deviceInfo, runtime.Version)
		} else if runtime.Version != "" {
			deviceInfo = runtime.Version
		}
		status := "online"
		if runtime.Status == "offline" {
			status = "offline"
		}
		metadata, _ := json.Marshal(map[string]any{
			"version": runtime.Version,
		})

		registered, err := h.Queries.UpsertAgentRuntime(r.Context(), db.UpsertAgentRuntimeParams{
			WorkspaceID: parseUUID(req.WorkspaceID),
			DaemonID:    strToText(req.DaemonID),
			Name:        name,
			RuntimeMode: "local",
			Provider:    provider,
			Status:      status,
			DeviceInfo:  deviceInfo,
			Metadata:    metadata,
		})
		if err != nil {
			writeError(w, http.StatusInternalServerError, "failed to register runtime: "+err.Error())
			return
		}
		resp = append(resp, runtimeToResponse(registered))
	}

	h.publish(protocol.EventDaemonRegister, req.WorkspaceID, "system", "", map[string]any{
		"runtimes": resp,
	})

	writeJSON(w, http.StatusOK, map[string]any{"runtimes": resp})
}

type DaemonHeartbeatRequest struct {
	RuntimeID string `json:"runtime_id"`
}

func (h *Handler) DaemonHeartbeat(w http.ResponseWriter, r *http.Request) {
	var req DaemonHeartbeatRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	if req.RuntimeID == "" {
		writeError(w, http.StatusBadRequest, "runtime_id is required")
		return
	}

	_, err := h.Queries.UpdateAgentRuntimeHeartbeat(r.Context(), parseUUID(req.RuntimeID))
	if err != nil {
		writeError(w, http.StatusInternalServerError, "heartbeat failed")
		return
	}

	writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}

// ClaimTaskByRuntime atomically claims the next queued task for a runtime.
func (h *Handler) ClaimTaskByRuntime(w http.ResponseWriter, r *http.Request) {
	runtimeID := chi.URLParam(r, "runtimeId")

	task, err := h.TaskService.ClaimTaskForRuntime(r.Context(), parseUUID(runtimeID))
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to claim task: "+err.Error())
		return
	}

	if task == nil {
		writeJSON(w, http.StatusOK, map[string]any{"task": nil})
		return
	}

	writeJSON(w, http.StatusOK, map[string]any{"task": taskToResponse(*task)})
}

// ListPendingTasksByRuntime returns queued/dispatched tasks for a runtime.
func (h *Handler) ListPendingTasksByRuntime(w http.ResponseWriter, r *http.Request) {
	runtimeID := chi.URLParam(r, "runtimeId")

	tasks, err := h.Queries.ListPendingTasksByRuntime(r.Context(), parseUUID(runtimeID))
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to list pending tasks")
		return
	}

	resp := make([]AgentTaskResponse, len(tasks))
	for i, t := range tasks {
		resp[i] = taskToResponse(t)
	}

	writeJSON(w, http.StatusOK, resp)
}

// ---------------------------------------------------------------------------
// Task Lifecycle (called by daemon)
// ---------------------------------------------------------------------------

// StartTask marks a dispatched task as running.
func (h *Handler) StartTask(w http.ResponseWriter, r *http.Request) {
	taskID := chi.URLParam(r, "taskId")

	task, err := h.TaskService.StartTask(r.Context(), parseUUID(taskID))
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, taskToResponse(*task))
}

// ReportTaskProgress broadcasts a progress update.
type TaskProgressRequest struct {
	Summary string `json:"summary"`
	Step    int    `json:"step"`
	Total   int    `json:"total"`
}

func (h *Handler) ReportTaskProgress(w http.ResponseWriter, r *http.Request) {
	taskID := chi.URLParam(r, "taskId")

	var req TaskProgressRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	// Look up task to get workspace ID via the associated issue.
	workspaceID := ""
	task, err := h.Queries.GetAgentTask(r.Context(), parseUUID(taskID))
	if err == nil {
		if issue, err := h.Queries.GetIssue(r.Context(), task.IssueID); err == nil {
			workspaceID = uuidToString(issue.WorkspaceID)
		}
	}

	h.TaskService.ReportProgress(r.Context(), taskID, workspaceID, req.Summary, req.Step, req.Total)
	writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}

// CompleteTask marks a running task as completed.
type TaskCompleteRequest struct {
	PRURL  string `json:"pr_url"`
	Output string `json:"output"`
}

func (h *Handler) CompleteTask(w http.ResponseWriter, r *http.Request) {
	taskID := chi.URLParam(r, "taskId")

	var req TaskCompleteRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	result, _ := json.Marshal(req)
	task, err := h.TaskService.CompleteTask(r.Context(), parseUUID(taskID), result)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, taskToResponse(*task))
}

// FailTask marks a running task as failed.
type TaskFailRequest struct {
	Error string `json:"error"`
}

func (h *Handler) FailTask(w http.ResponseWriter, r *http.Request) {
	taskID := chi.URLParam(r, "taskId")

	var req TaskFailRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	task, err := h.TaskService.FailTask(r.Context(), parseUUID(taskID), req.Error)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}

	writeJSON(w, http.StatusOK, taskToResponse(*task))
}