import { create } from "zustand";
import { subscribeWithSelector } from "zustand/middleware";
import type { DaemonClient } from "@server/client/daemon-client";
import type { useAudioPlayer } from "@/hooks/use-audio-player";
import type { AgentDirectoryEntry } from "@/types/agent-directory";
import type { StreamItem } from "@/types/stream";
import type { PendingPermission } from "@/types/shared";
import type { AgentLifecycleStatus } from "@server/shared/agent-lifecycle";
import type {
  AgentPermissionResponse,
  AgentPermissionRequest,
  AgentSessionConfig,
  AgentProvider,
  AgentMode,
  AgentCapabilityFlags,
  AgentModelDefinition,
  AgentUsage,
  AgentPersistenceHandle,
} from "@server/server/agent/agent-sdk-types";
import type {
  FileDownloadTokenResponse,
  GitSetupOptions,
  ProjectPlacementPayload,
} from "@server/shared/messages";
import { isPerfLoggingEnabled, measurePayload, perfLog } from "@/utils/perf";

// Re-export types that were in session-context
export type MessageEntry =
  | {
      type: "user";
      id: string;
      timestamp: number;
      message: string;
    }
  | {
      type: "assistant";
      id: string;
      timestamp: number;
      message: string;
    }
  | {
      type: "activity";
      id: string;
      timestamp: number;
      activityType: "system" | "info" | "success" | "error";
      message: string;
      metadata?: Record<string, unknown>;
    }
  | {
      type: "artifact";
      id: string;
      timestamp: number;
      artifactId: string;
      artifactType: string;
      title: string;
    }
  | {
      type: "tool_call";
      id: string;
      timestamp: number;
      toolName: string;
      args: unknown | null;
      result?: unknown | null;
      error?: unknown | null;
      status: "executing" | "completed" | "failed";
    };

export interface AgentRuntimeInfo {
  provider: AgentProvider;
  sessionId: string | null;
  model?: string | null;
  modeId?: string | null;
  extra?: Record<string, unknown>;
}

export interface Agent {
  serverId: string;
  id: string;
  provider: AgentProvider;
  status: AgentLifecycleStatus;
  createdAt: Date;
  updatedAt: Date;
  lastUserMessageAt: Date | null;
  lastActivityAt: Date;
  capabilities: AgentCapabilityFlags;
  currentModeId: string | null;
  availableModes: AgentMode[];
  pendingPermissions: AgentPermissionRequest[];
  persistence: AgentPersistenceHandle | null;
  runtimeInfo?: AgentRuntimeInfo;
  lastUsage?: AgentUsage;
  lastError?: string | null;
  title: string | null;
  cwd: string;
  model: string | null;
  thinkingOptionId?: string | null;
  requiresAttention?: boolean;
  attentionReason?: "finished" | "error" | "permission" | null;
  attentionTimestamp?: Date | null;
  archivedAt?: Date | null;
  labels: Record<string, string>;
  projectPlacement?: ProjectPlacementPayload | null;
}

export type ExplorerEntryKind = "file" | "directory";
export type ExplorerFileKind = "text" | "image" | "binary";
export type ExplorerEncoding = "utf-8" | "base64" | "none";

export interface ExplorerEntry {
  name: string;
  path: string;
  kind: ExplorerEntryKind;
  size: number;
  modifiedAt: string;
}

export interface ExplorerFile {
  path: string;
  kind: ExplorerFileKind;
  encoding: ExplorerEncoding;
  content?: string;
  mimeType?: string;
  size: number;
  modifiedAt: string;
}

interface ExplorerDirectory {
  path: string;
  entries: ExplorerEntry[];
}

interface ExplorerRequestState {
  path: string;
  mode: "list" | "file";
}

export interface AgentFileExplorerState {
  directories: Map<string, ExplorerDirectory>;
  files: Map<string, ExplorerFile>;
  isLoading: boolean;
  lastError: string | null;
  pendingRequest: ExplorerRequestState | null;
  currentPath: string;
  history: string[];
  lastVisitedPath: string;
  selectedEntryPath: string | null;
}

export interface DaemonConnectionSnapshot {
  isConnected: boolean;
  isConnecting: boolean;
  lastError: string | null;
}

export type DaemonServerInfo = {
  serverId: string;
  hostname: string | null;
};

// Per-session state
export interface SessionState {
  serverId: string;

  // Daemon client (immutable reference)
  client: DaemonClient | null;

  // Connection snapshot (mutable)
  connection: DaemonConnectionSnapshot;

  // Server metadata (from server_info handshake)
  serverInfo: DaemonServerInfo | null;

  // Audio player (immutable reference)
  audioPlayer: ReturnType<typeof useAudioPlayer> | null;

  // Hydration status
  hasHydratedAgents: boolean;

  // Audio state
  isPlayingAudio: boolean;

  // Focus
  focusedAgentId: string | null;

  // Messages
  messages: MessageEntry[];
  currentAssistantMessage: string;

  // Stream state (head/tail model)
  agentStreamTail: Map<string, StreamItem[]>;
  agentStreamHead: Map<string, StreamItem[]>;
  historySyncGeneration: number;
  agentHistorySyncGeneration: Map<string, number>;

  // Initializing agents (used for UI loading state)
  initializingAgents: Map<string, boolean>;

  // Agents
  agents: Map<string, Agent>;

  // Permissions
  pendingPermissions: Map<string, PendingPermission>;

  // File explorer
  fileExplorer: Map<string, AgentFileExplorerState>;

  // Queued messages
  queuedMessages: Map<string, Array<{ id: string; text: string; images?: Array<{ uri: string; mimeType: string }> }>>;
}

// Global store state
interface SessionStoreState {
  sessions: Record<string, SessionState>;

  // Agent activity timestamps (top-level, keyed by agentId to prevent cascade rerenders)
  agentLastActivity: Map<string, Date>;
}

// Action types
interface SessionStoreActions {
  // Session management
  initializeSession: (serverId: string, client: DaemonClient, audioPlayer: ReturnType<typeof useAudioPlayer>) => void;
  clearSession: (serverId: string) => void;
  getSession: (serverId: string) => SessionState | undefined;
  updateSessionClient: (serverId: string, client: DaemonClient) => void;
  updateSessionConnection: (serverId: string, connection: DaemonConnectionSnapshot) => void;
  updateSessionServerInfo: (serverId: string, info: DaemonServerInfo) => void;

  // Audio state
  setIsPlayingAudio: (serverId: string, playing: boolean) => void;

  // Focus
  setFocusedAgentId: (serverId: string, agentId: string | null) => void;

  // Messages
  setMessages: (serverId: string, messages: MessageEntry[] | ((prev: MessageEntry[]) => MessageEntry[])) => void;
  setCurrentAssistantMessage: (serverId: string, message: string | ((prev: string) => string)) => void;

  // Stream state (head/tail model)
  setAgentStreamTail: (serverId: string, state: Map<string, StreamItem[]> | ((prev: Map<string, StreamItem[]>) => Map<string, StreamItem[]>)) => void;
  setAgentStreamHead: (serverId: string, state: Map<string, StreamItem[]> | ((prev: Map<string, StreamItem[]>) => Map<string, StreamItem[]>)) => void;
  clearAgentStreamHead: (serverId: string, agentId: string) => void;
  bumpHistorySyncGeneration: (serverId: string) => void;
  markAgentHistorySynchronized: (serverId: string, agentId: string) => void;

  // Initializing agents
  setInitializingAgents: (serverId: string, state: Map<string, boolean> | ((prev: Map<string, boolean>) => Map<string, boolean>)) => void;

  // Agents
  setAgents: (serverId: string, agents: Map<string, Agent> | ((prev: Map<string, Agent>) => Map<string, Agent>)) => void;

  // Agent activity timestamps
  setAgentLastActivity: (agentId: string, timestamp: Date) => void;

  // Permissions
  setPendingPermissions: (serverId: string, perms: Map<string, PendingPermission> | ((prev: Map<string, PendingPermission>) => Map<string, PendingPermission>)) => void;

  // File explorer
  setFileExplorer: (serverId: string, state: Map<string, AgentFileExplorerState> | ((prev: Map<string, AgentFileExplorerState>) => Map<string, AgentFileExplorerState>)) => void;

  // Queued messages
  setQueuedMessages: (serverId: string, value: Map<string, Array<{ id: string; text: string; images?: Array<{ uri: string; mimeType: string }> }>> | ((prev: Map<string, Array<{ id: string; text: string; images?: Array<{ uri: string; mimeType: string }> }>>) => Map<string, Array<{ id: string; text: string; images?: Array<{ uri: string; mimeType: string }> }>>)) => void;

  // Hydration
  setHasHydratedAgents: (serverId: string, hydrated: boolean) => void;

  // Agent directory (derived from agents)
  getAgentDirectory: (serverId: string) => AgentDirectoryEntry[] | undefined;
}

type SessionStore = SessionStoreState & SessionStoreActions;

const SESSION_STORE_LOG_TAG = "[SessionStore]";
let sessionStoreUpdateCount = 0;

function logSessionStoreUpdate(
  type: string,
  serverId: string,
  payload?: unknown
) {
  if (!isPerfLoggingEnabled()) {
    return;
  }
  sessionStoreUpdateCount += 1;
  const metrics = payload ? measurePayload(payload) : null;
  perfLog(SESSION_STORE_LOG_TAG, {
    event: type,
    serverId,
    updateCount: sessionStoreUpdateCount,
    payloadApproxBytes: metrics?.approxBytes ?? 0,
    payloadFieldCount: metrics?.fieldCount ?? 0,
    timestamp: Date.now(),
  });
}


function createDefaultConnectionSnapshot(client?: DaemonClient | null): DaemonConnectionSnapshot {
  if (!client) {
    return { isConnected: false, isConnecting: false, lastError: null };
  }
  const state = client.getConnectionState();
  return {
    isConnected: state.status === "connected",
    isConnecting: state.status === "connecting",
    lastError: state.status === "disconnected" ? state.reason ?? client.lastError ?? null : null,
  };
}

// Helper to create initial session state
function createInitialSessionState(serverId: string, client: DaemonClient, audioPlayer: ReturnType<typeof useAudioPlayer>): SessionState {
  return {
    serverId,
    client,
    connection: createDefaultConnectionSnapshot(client),
    serverInfo: null,
    audioPlayer,
    hasHydratedAgents: false,
    isPlayingAudio: false,
    focusedAgentId: null,
    messages: [],
    currentAssistantMessage: "",
    agentStreamTail: new Map(),
    agentStreamHead: new Map(),
    historySyncGeneration: 0,
    agentHistorySyncGeneration: new Map(),
    initializingAgents: new Map(),
    agents: new Map(),
    pendingPermissions: new Map(),
    fileExplorer: new Map(),
    queuedMessages: new Map(),
  };
}

export const useSessionStore = create<SessionStore>()(
  subscribeWithSelector((set, get) => ({
    sessions: {},
    agentLastActivity: new Map(),

    // Session management
    initializeSession: (serverId, client, audioPlayer) => {
      set((prev) => {
        if (prev.sessions[serverId]) {
          return prev;
        }
        logSessionStoreUpdate("initializeSession", serverId);
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: createInitialSessionState(serverId, client, audioPlayer),
          },
        };
      });
    },

    clearSession: (serverId) => {
      set((prev) => {
        if (!(serverId in prev.sessions)) {
          return prev;
        }
        logSessionStoreUpdate("clearSession", serverId);
        const nextSessions = { ...prev.sessions };
        delete nextSessions[serverId];
        return { ...prev, sessions: nextSessions };
      });
    },

    updateSessionClient: (serverId, client) => {
      set((prev) => {
        const session = prev.sessions[serverId];

        if (!session) {
          return prev;
        }

        if (session.client === client) {
          return prev;
        }

        logSessionStoreUpdate("updateSessionClient", serverId, {
          wasNull: session.client === null,
          isNowConnected: client.isConnected,
          isNowConnecting: client.isConnecting,
        });

        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: {
              ...session,
              client,
            },
          },
        };
      });
    },

    updateSessionConnection: (serverId, connection) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        if (
          session.connection.isConnected === connection.isConnected &&
          session.connection.isConnecting === connection.isConnecting &&
          session.connection.lastError === connection.lastError
        ) {
          return prev;
        }
        logSessionStoreUpdate("updateSessionConnection", serverId, connection);
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: {
              ...session,
              connection,
            },
          },
        };
      });
    },

    updateSessionServerInfo: (serverId, info) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }

        const nextHostname = info.hostname?.trim() || null;
        const prevHostname = session.serverInfo?.hostname?.trim() || null;

        if (session.serverInfo?.serverId === info.serverId && prevHostname === nextHostname) {
          return prev;
        }

        logSessionStoreUpdate("updateSessionServerInfo", serverId, {
          serverId: info.serverId,
          hostname: nextHostname,
        });

        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: {
              ...session,
              serverInfo: { serverId: info.serverId, hostname: nextHostname },
            },
          },
        };
      });
    },

    getSession: (serverId) => {
      return get().sessions[serverId];
    },

    // Audio state
    setIsPlayingAudio: (serverId, playing) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session || session.isPlayingAudio === playing) {
          return prev;
        }
        logSessionStoreUpdate("setIsPlayingAudio", serverId, { playing });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, isPlayingAudio: playing },
          },
        };
      });
    },

    // Focus
    setFocusedAgentId: (serverId, agentId) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session || session.focusedAgentId === agentId) {
          return prev;
        }
        logSessionStoreUpdate("setFocusedAgentId", serverId, { agentId });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, focusedAgentId: agentId },
          },
        };
      });
    },

    // Messages
    setMessages: (serverId, messages) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextMessages = typeof messages === "function" ? messages(session.messages) : messages;
        if (session.messages === nextMessages) {
          return prev;
        }
        logSessionStoreUpdate("setMessages", serverId, { count: nextMessages.length });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, messages: nextMessages },
          },
        };
      });
    },

    setCurrentAssistantMessage: (serverId, message) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextMessage = typeof message === "function" ? message(session.currentAssistantMessage) : message;
        if (session.currentAssistantMessage === nextMessage) {
          return prev;
        }
        logSessionStoreUpdate("setCurrentAssistantMessage", serverId, { length: nextMessage.length });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, currentAssistantMessage: nextMessage },
          },
        };
      });
    },

    // Stream state (head/tail model)
    setAgentStreamTail: (serverId, state) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextState = typeof state === "function" ? state(session.agentStreamTail) : state;
        if (session.agentStreamTail === nextState) {
          return prev;
        }
        logSessionStoreUpdate("setAgentStreamTail", serverId, { agentCount: nextState.size });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, agentStreamTail: nextState },
          },
        };
      });
    },

    setAgentStreamHead: (serverId, state) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextState = typeof state === "function" ? state(session.agentStreamHead) : state;
        if (session.agentStreamHead === nextState) {
          return prev;
        }
        logSessionStoreUpdate("setAgentStreamHead", serverId, { agentCount: nextState.size });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, agentStreamHead: nextState },
          },
        };
      });
    },

    clearAgentStreamHead: (serverId, agentId) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        if (!session.agentStreamHead.has(agentId)) {
          return prev;
        }
        const nextHead = new Map(session.agentStreamHead);
        nextHead.delete(agentId);
        logSessionStoreUpdate("clearAgentStreamHead", serverId, { agentId });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, agentStreamHead: nextHead },
          },
        };
      });
    },

    bumpHistorySyncGeneration: (serverId) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextGeneration = session.historySyncGeneration + 1;
        logSessionStoreUpdate("bumpHistorySyncGeneration", serverId, {
          generation: nextGeneration,
        });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: {
              ...session,
              historySyncGeneration: nextGeneration,
            },
          },
        };
      });
    },

    markAgentHistorySynchronized: (serverId, agentId) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const currentGeneration = session.historySyncGeneration;
        const previousGeneration = session.agentHistorySyncGeneration.get(agentId);
        if (previousGeneration === currentGeneration) {
          return prev;
        }
        const nextMap = new Map(session.agentHistorySyncGeneration);
        nextMap.set(agentId, currentGeneration);
        logSessionStoreUpdate("markAgentHistorySynchronized", serverId, {
          agentId,
          generation: currentGeneration,
        });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: {
              ...session,
              agentHistorySyncGeneration: nextMap,
            },
          },
        };
      });
    },

    // Initializing agents
    setInitializingAgents: (serverId, state) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextState = typeof state === "function" ? state(session.initializingAgents) : state;
        if (session.initializingAgents === nextState) {
          return prev;
        }
        logSessionStoreUpdate("setInitializingAgents", serverId, { count: nextState.size });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, initializingAgents: nextState },
          },
        };
      });
    },

    // Agents
    setAgents: (serverId, agents) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextAgents = typeof agents === "function" ? agents(session.agents) : agents;
        if (session.agents === nextAgents) {
          return prev;
        }
        logSessionStoreUpdate("setAgents", serverId, { count: nextAgents.size });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, agents: nextAgents },
          },
        };
      });
    },

    // Agent activity timestamps (top-level, does NOT mutate session object)
    setAgentLastActivity: (agentId, timestamp) => {
      set((prev) => {
        const currentTimestamp = prev.agentLastActivity.get(agentId);
        if (currentTimestamp && currentTimestamp.getTime() === timestamp.getTime()) {
          return prev;
        }
        const nextActivity = new Map(prev.agentLastActivity);
        nextActivity.set(agentId, timestamp);
        return {
          ...prev,
          agentLastActivity: nextActivity,
        };
      });
    },

    // Permissions
    setPendingPermissions: (serverId, perms) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextPerms = typeof perms === "function" ? perms(session.pendingPermissions) : perms;
        if (session.pendingPermissions === nextPerms) {
          return prev;
        }
        logSessionStoreUpdate("setPendingPermissions", serverId, { count: nextPerms.size });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, pendingPermissions: nextPerms },
          },
        };
      });
    },

    // File explorer
    setFileExplorer: (serverId, state) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextState = typeof state === "function" ? state(session.fileExplorer) : state;
        if (session.fileExplorer === nextState) {
          return prev;
        }
        logSessionStoreUpdate("setFileExplorer", serverId, { agentCount: nextState.size });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, fileExplorer: nextState },
          },
        };
      });
    },

    // Queued messages
    setQueuedMessages: (serverId, value) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session) {
          return prev;
        }
        const nextValue = typeof value === "function" ? value(session.queuedMessages) : value;
        if (session.queuedMessages === nextValue) {
          return prev;
        }
        logSessionStoreUpdate("setQueuedMessages", serverId, { agentCount: nextValue.size });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, queuedMessages: nextValue },
          },
        };
      });
    },

    // Hydration
    setHasHydratedAgents: (serverId, hydrated) => {
      set((prev) => {
        const session = prev.sessions[serverId];
        if (!session || session.hasHydratedAgents === hydrated) {
          return prev;
        }
        logSessionStoreUpdate("setHasHydratedAgents", serverId, { hydrated });
        return {
          ...prev,
          sessions: {
            ...prev.sessions,
            [serverId]: { ...session, hasHydratedAgents: hydrated },
          },
        };
      });
    },

    // Agent directory - derived from agents (computed on-demand)
    getAgentDirectory: (serverId) => {
      const state = get();
      const session = state.sessions[serverId];
      if (!session) {
        return undefined;
      }

      const entries: AgentDirectoryEntry[] = [];
      for (const agent of session.agents.values()) {
        // Get lastActivityAt from top-level slice, fallback to agent.lastActivityAt
        const lastActivityAt = state.agentLastActivity.get(agent.id) ?? agent.lastActivityAt;
        entries.push({
          id: agent.id,
          serverId,
          title: agent.title ?? null,
          status: agent.status,
          lastActivityAt,
          cwd: agent.cwd,
          provider: agent.provider,
          requiresAttention: agent.requiresAttention ?? false,
          attentionReason: agent.attentionReason ?? null,
          attentionTimestamp: agent.attentionTimestamp ?? null,
          labels: agent.labels,
        });
      }
      return entries;
    },
  }))
);