package handler

import (
	"encoding/json"
	"log/slog"
	"net/http"
	"strconv"
	"time"

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

type AgentRuntimeResponse struct {
	ID           string  `json:"id"`
	WorkspaceID  string  `json:"workspace_id"`
	DaemonID     *string `json:"daemon_id"`
	Name         string  `json:"name"`
	RuntimeMode  string  `json:"runtime_mode"`
	Provider     string  `json:"provider"`
	LaunchHeader string  `json:"launch_header"`
	Status       string  `json:"status"`
	DeviceInfo   string  `json:"device_info"`
	Metadata     any     `json:"metadata"`
	OwnerID      *string `json:"owner_id"`
	LastSeenAt   *string `json:"last_seen_at"`
	CreatedAt    string  `json:"created_at"`
	UpdatedAt    string  `json:"updated_at"`
}

func runtimeToResponse(rt db.AgentRuntime) AgentRuntimeResponse {
	var metadata any
	if rt.Metadata != nil {
		json.Unmarshal(rt.Metadata, &metadata)
	}
	if metadata == nil {
		metadata = map[string]any{}
	}

	return AgentRuntimeResponse{
		ID:           uuidToString(rt.ID),
		WorkspaceID:  uuidToString(rt.WorkspaceID),
		DaemonID:     textToPtr(rt.DaemonID),
		Name:         rt.Name,
		RuntimeMode:  rt.RuntimeMode,
		Provider:     rt.Provider,
		LaunchHeader: agent.LaunchHeader(rt.Provider),
		Status:       rt.Status,
		DeviceInfo:   rt.DeviceInfo,
		Metadata:     metadata,
		OwnerID:      uuidToPtr(rt.OwnerID),
		LastSeenAt:   timestampToPtr(rt.LastSeenAt),
		CreatedAt:    timestampToString(rt.CreatedAt),
		UpdatedAt:    timestampToString(rt.UpdatedAt),
	}
}

// ---------------------------------------------------------------------------
// Runtime Usage
// ---------------------------------------------------------------------------

type RuntimeUsageResponse struct {
	RuntimeID        string `json:"runtime_id"`
	Date             string `json:"date"`
	Provider         string `json:"provider"`
	Model            string `json:"model"`
	InputTokens      int64  `json:"input_tokens"`
	OutputTokens     int64  `json:"output_tokens"`
	CacheReadTokens  int64  `json:"cache_read_tokens"`
	CacheWriteTokens int64  `json:"cache_write_tokens"`
}

// GetRuntimeUsage returns daily token usage for a runtime, aggregated from
// per-task usage records captured by the daemon. This is scoped to
// Daemon-executed tasks only (i.e. excludes users' local CLI usage of the
// same tool).
func (h *Handler) GetRuntimeUsage(w http.ResponseWriter, r *http.Request) {
	runtimeID := chi.URLParam(r, "runtimeId")
	runtimeUUID, ok := parseUUIDOrBadRequest(w, runtimeID, "runtime_id")
	if !ok {
		return
	}

	rt, err := h.Queries.GetAgentRuntime(r.Context(), runtimeUUID)
	if err != nil {
		writeError(w, http.StatusNotFound, "runtime not found")
		return
	}

	if _, ok := h.requireWorkspaceMember(w, r, uuidToString(rt.WorkspaceID), "runtime not found"); !ok {
		return
	}

	since := parseSinceParam(r, 90)

	rows, err := h.Queries.ListRuntimeUsage(r.Context(), db.ListRuntimeUsageParams{
		RuntimeID: rt.ID,
		Since:     since,
	})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to list usage")
		return
	}

	resp := make([]RuntimeUsageResponse, len(rows))
	resolvedRuntimeID := uuidToString(rt.ID)
	for i, row := range rows {
		resp[i] = RuntimeUsageResponse{
			RuntimeID:        resolvedRuntimeID,
			Date:             row.Date.Time.Format("2006-01-02"),
			Provider:         row.Provider,
			Model:            row.Model,
			InputTokens:      row.InputTokens,
			OutputTokens:     row.OutputTokens,
			CacheReadTokens:  row.CacheReadTokens,
			CacheWriteTokens: row.CacheWriteTokens,
		}
	}

	writeJSON(w, http.StatusOK, resp)
}

// GetRuntimeTaskActivity returns hourly task activity distribution for a runtime.
func (h *Handler) GetRuntimeTaskActivity(w http.ResponseWriter, r *http.Request) {
	runtimeID := chi.URLParam(r, "runtimeId")
	runtimeUUID, ok := parseUUIDOrBadRequest(w, runtimeID, "runtime_id")
	if !ok {
		return
	}

	rt, err := h.Queries.GetAgentRuntime(r.Context(), runtimeUUID)
	if err != nil {
		writeError(w, http.StatusNotFound, "runtime not found")
		return
	}

	if _, ok := h.requireWorkspaceMember(w, r, uuidToString(rt.WorkspaceID), "runtime not found"); !ok {
		return
	}

	rows, err := h.Queries.GetRuntimeTaskHourlyActivity(r.Context(), rt.ID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to get task activity")
		return
	}

	type HourlyActivity struct {
		Hour  int `json:"hour"`
		Count int `json:"count"`
	}

	resp := make([]HourlyActivity, len(rows))
	for i, row := range rows {
		resp[i] = HourlyActivity{Hour: int(row.Hour), Count: int(row.Count)}
	}

	writeJSON(w, http.StatusOK, resp)
}

// RuntimeUsageByAgentResponse is one (agent, model) row of "Cost by agent".
// Model stays on the wire because cost is computed client-side from a model
// pricing table, intentionally not stored server-side so pricing changes
// don't require a back-fill. The client groups by agent_id and sums.
type RuntimeUsageByAgentResponse struct {
	AgentID          string `json:"agent_id"`
	Model            string `json:"model"`
	InputTokens      int64  `json:"input_tokens"`
	OutputTokens     int64  `json:"output_tokens"`
	CacheReadTokens  int64  `json:"cache_read_tokens"`
	CacheWriteTokens int64  `json:"cache_write_tokens"`
	TaskCount        int32  `json:"task_count"`
}

// GetRuntimeUsageByAgent returns per-agent token aggregates for a runtime
// since the cutoff window. Drives the runtime-detail "Cost by agent" tab.
func (h *Handler) GetRuntimeUsageByAgent(w http.ResponseWriter, r *http.Request) {
	runtimeID := chi.URLParam(r, "runtimeId")

	rt, err := h.Queries.GetAgentRuntime(r.Context(), parseUUID(runtimeID))
	if err != nil {
		writeError(w, http.StatusNotFound, "runtime not found")
		return
	}

	if _, ok := h.requireWorkspaceMember(w, r, uuidToString(rt.WorkspaceID), "runtime not found"); !ok {
		return
	}

	since := parseSinceParam(r, 30)

	rows, err := h.Queries.ListRuntimeUsageByAgent(r.Context(), db.ListRuntimeUsageByAgentParams{
		RuntimeID: parseUUID(runtimeID),
		Since:     since,
	})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to list usage by agent")
		return
	}

	resp := make([]RuntimeUsageByAgentResponse, len(rows))
	for i, row := range rows {
		resp[i] = RuntimeUsageByAgentResponse{
			AgentID:          uuidToString(row.AgentID),
			Model:            row.Model,
			InputTokens:      row.InputTokens,
			OutputTokens:     row.OutputTokens,
			CacheReadTokens:  row.CacheReadTokens,
			CacheWriteTokens: row.CacheWriteTokens,
			TaskCount:        row.TaskCount,
		}
	}

	writeJSON(w, http.StatusOK, resp)
}

// RuntimeUsageByHourResponse is one (hour, model) row. Hours with zero
// activity are omitted by the SQL — clients fill the gap to render a
// continuous 0..23 axis. Model is preserved for client-side cost math.
type RuntimeUsageByHourResponse struct {
	Hour             int    `json:"hour"`
	Model            string `json:"model"`
	InputTokens      int64  `json:"input_tokens"`
	OutputTokens     int64  `json:"output_tokens"`
	CacheReadTokens  int64  `json:"cache_read_tokens"`
	CacheWriteTokens int64  `json:"cache_write_tokens"`
	TaskCount        int32  `json:"task_count"`
}

// GetRuntimeUsageByHour returns hourly (0..23) token aggregates for a
// runtime since the cutoff window. Drives the "By hour" tab.
func (h *Handler) GetRuntimeUsageByHour(w http.ResponseWriter, r *http.Request) {
	runtimeID := chi.URLParam(r, "runtimeId")

	rt, err := h.Queries.GetAgentRuntime(r.Context(), parseUUID(runtimeID))
	if err != nil {
		writeError(w, http.StatusNotFound, "runtime not found")
		return
	}

	if _, ok := h.requireWorkspaceMember(w, r, uuidToString(rt.WorkspaceID), "runtime not found"); !ok {
		return
	}

	since := parseSinceParam(r, 30)

	rows, err := h.Queries.GetRuntimeUsageByHour(r.Context(), db.GetRuntimeUsageByHourParams{
		RuntimeID: parseUUID(runtimeID),
		Since:     since,
	})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to get usage by hour")
		return
	}

	resp := make([]RuntimeUsageByHourResponse, len(rows))
	for i, row := range rows {
		resp[i] = RuntimeUsageByHourResponse{
			Hour:             int(row.Hour),
			Model:            row.Model,
			InputTokens:      row.InputTokens,
			OutputTokens:     row.OutputTokens,
			CacheReadTokens:  row.CacheReadTokens,
			CacheWriteTokens: row.CacheWriteTokens,
			TaskCount:        row.TaskCount,
		}
	}

	writeJSON(w, http.StatusOK, resp)
}

// GetWorkspaceUsageByDay returns daily token usage aggregated by model for the workspace.
func (h *Handler) GetWorkspaceUsageByDay(w http.ResponseWriter, r *http.Request) {
	workspaceID := h.resolveWorkspaceID(r)
	since := parseSinceParam(r, 30)

	rows, err := h.Queries.GetWorkspaceUsageByDay(r.Context(), db.GetWorkspaceUsageByDayParams{
		WorkspaceID: parseUUID(workspaceID),
		Since:       since,
	})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to get usage")
		return
	}

	type DailyUsageRow struct {
		Date                  string `json:"date"`
		Model                 string `json:"model"`
		TotalInputTokens      int64  `json:"total_input_tokens"`
		TotalOutputTokens     int64  `json:"total_output_tokens"`
		TotalCacheReadTokens  int64  `json:"total_cache_read_tokens"`
		TotalCacheWriteTokens int64  `json:"total_cache_write_tokens"`
		TaskCount             int32  `json:"task_count"`
	}

	resp := make([]DailyUsageRow, len(rows))
	for i, row := range rows {
		resp[i] = DailyUsageRow{
			Date:                  row.Date.Time.Format("2006-01-02"),
			Model:                 row.Model,
			TotalInputTokens:      row.TotalInputTokens,
			TotalOutputTokens:     row.TotalOutputTokens,
			TotalCacheReadTokens:  row.TotalCacheReadTokens,
			TotalCacheWriteTokens: row.TotalCacheWriteTokens,
			TaskCount:             row.TaskCount,
		}
	}

	writeJSON(w, http.StatusOK, resp)
}

// GetWorkspaceUsageSummary returns total token usage aggregated by model for the workspace.
func (h *Handler) GetWorkspaceUsageSummary(w http.ResponseWriter, r *http.Request) {
	workspaceID := h.resolveWorkspaceID(r)
	since := parseSinceParam(r, 30)

	rows, err := h.Queries.GetWorkspaceUsageSummary(r.Context(), db.GetWorkspaceUsageSummaryParams{
		WorkspaceID: parseUUID(workspaceID),
		Since:       since,
	})
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to get usage summary")
		return
	}

	type UsageSummaryRow struct {
		Model                 string `json:"model"`
		TotalInputTokens      int64  `json:"total_input_tokens"`
		TotalOutputTokens     int64  `json:"total_output_tokens"`
		TotalCacheReadTokens  int64  `json:"total_cache_read_tokens"`
		TotalCacheWriteTokens int64  `json:"total_cache_write_tokens"`
		TaskCount             int32  `json:"task_count"`
	}

	resp := make([]UsageSummaryRow, len(rows))
	for i, row := range rows {
		resp[i] = UsageSummaryRow{
			Model:                 row.Model,
			TotalInputTokens:      row.TotalInputTokens,
			TotalOutputTokens:     row.TotalOutputTokens,
			TotalCacheReadTokens:  row.TotalCacheReadTokens,
			TotalCacheWriteTokens: row.TotalCacheWriteTokens,
			TaskCount:             row.TaskCount,
		}
	}

	writeJSON(w, http.StatusOK, resp)
}

// parseSinceParam parses the "days" query parameter and returns a timestamptz.
func parseSinceParam(r *http.Request, defaultDays int) pgtype.Timestamptz {
	days := defaultDays
	if d := r.URL.Query().Get("days"); d != "" {
		if parsed, err := strconv.Atoi(d); err == nil && parsed > 0 && parsed <= 365 {
			days = parsed
		}
	}
	t := time.Now().AddDate(0, 0, -days)
	return pgtype.Timestamptz{Time: t, Valid: true}
}

func (h *Handler) ListAgentRuntimes(w http.ResponseWriter, r *http.Request) {
	workspaceID := h.resolveWorkspaceID(r)

	var runtimes []db.AgentRuntime
	var err error

	if ownerFilter := r.URL.Query().Get("owner"); ownerFilter == "me" {
		userID, ok := requireUserID(w, r)
		if !ok {
			return
		}
		runtimes, err = h.Queries.ListAgentRuntimesByOwner(r.Context(), db.ListAgentRuntimesByOwnerParams{
			WorkspaceID: parseUUID(workspaceID),
			OwnerID:     parseUUID(userID),
		})
	} else {
		runtimes, err = h.Queries.ListAgentRuntimes(r.Context(), parseUUID(workspaceID))
	}

	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to list runtimes")
		return
	}

	resp := make([]AgentRuntimeResponse, len(runtimes))
	for i, rt := range runtimes {
		resp[i] = runtimeToResponse(rt)
	}

	writeJSON(w, http.StatusOK, resp)
}

// DeleteAgentRuntime deletes a runtime after permission and dependency checks.
func (h *Handler) DeleteAgentRuntime(w http.ResponseWriter, r *http.Request) {
	runtimeID := chi.URLParam(r, "runtimeId")
	runtimeUUID, ok := parseUUIDOrBadRequest(w, runtimeID, "runtime_id")
	if !ok {
		return
	}

	rt, err := h.Queries.GetAgentRuntime(r.Context(), runtimeUUID)
	if err != nil {
		writeError(w, http.StatusNotFound, "runtime not found")
		return
	}

	wsID := uuidToString(rt.WorkspaceID)
	member, ok := h.requireWorkspaceMember(w, r, wsID, "runtime not found")
	if !ok {
		return
	}

	// Permission: owner/admin can delete any runtime; members can only delete their own.
	userID := uuidToString(member.UserID)
	isAdmin := roleAllowed(member.Role, "owner", "admin")
	isOwner := rt.OwnerID.Valid && uuidToString(rt.OwnerID) == userID
	if !isAdmin && !isOwner {
		writeError(w, http.StatusForbidden, "you can only delete your own runtimes")
		return
	}

	// Check if any active (non-archived) agents are bound to this runtime.
	activeCount, err := h.Queries.CountActiveAgentsByRuntime(r.Context(), rt.ID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to check runtime dependencies")
		return
	}
	if activeCount > 0 {
		writeError(w, http.StatusConflict, "cannot delete runtime: it has active agents bound to it. Archive or reassign the agents first.")
		return
	}

	// Remove archived agents so the FK constraint (ON DELETE RESTRICT) won't block deletion.
	if err := h.Queries.DeleteArchivedAgentsByRuntime(r.Context(), rt.ID); err != nil {
		writeError(w, http.StatusInternalServerError, "failed to clean up archived agents")
		return
	}

	if err := h.Queries.DeleteAgentRuntime(r.Context(), rt.ID); err != nil {
		writeError(w, http.StatusInternalServerError, "failed to delete runtime")
		return
	}

	slog.Info("runtime deleted", "runtime_id", uuidToString(rt.ID), "deleted_by", userID)

	// Notify frontend to refresh runtime list.
	h.publish(protocol.EventDaemonRegister, wsID, "member", userID, map[string]any{
		"action": "delete",
	})

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