import { HttpService } from "@nestjs/axios";
import { Injectable, ServiceUnavailableException } from "@nestjs/common";
import type {
  AgentMessage,
  AgentMessageRole,
  AgentSession,
  AgentSessionList,
  AgentSessionStatus,
  IAgentProvider,
  InjectResult,
} from "@mosaic/shared";
import type { AgentProviderConfig } from "@prisma/client";
import { randomUUID } from "node:crypto";
import { EncryptionService } from "../../../security/encryption.service";
import { OpenClawSseBridge } from "./openclaw-sse.bridge";

const DEFAULT_SESSION_LIMIT = 50;
const DEFAULT_MESSAGE_LIMIT = 50;
const MAX_MESSAGE_LIMIT = 200;
const OPENCLAW_PROVIDER_TYPE = "openclaw";
const API_TOKEN_KEYS = ["apiToken", "token", "bearerToken"] as const;
const DISPLAY_NAME_KEYS = ["displayName", "label"] as const;

type JsonRecord = Record<string, unknown>;

interface HttpErrorWithResponse {
  response?: {
    status?: number;
  };
}

@Injectable()
export class OpenClawProvider implements IAgentProvider {
  readonly providerId: string;
  readonly providerType = OPENCLAW_PROVIDER_TYPE;
  readonly displayName: string;

  constructor(
    private readonly config: AgentProviderConfig,
    private readonly encryptionService: EncryptionService,
    private readonly httpService: HttpService,
    private readonly sseBridge: OpenClawSseBridge
  ) {
    this.providerId = this.config.name;
    this.displayName = this.resolveDisplayName();
  }

  validateBaseUrl(): void {
    void this.resolveBaseUrl();
  }

  validateToken(): void {
    void this.resolveApiToken();
  }

  async listSessions(cursor?: string, limit = DEFAULT_SESSION_LIMIT): Promise<AgentSessionList> {
    const safeLimit = this.normalizeLimit(limit, DEFAULT_SESSION_LIMIT);
    const params: Record<string, number | string> = { limit: safeLimit };
    if (typeof cursor === "string" && cursor.length > 0) {
      params.cursor = cursor;
    }

    try {
      const response = await this.httpService.axiosRef.get(this.buildUrl("/api/sessions"), {
        headers: this.authHeaders(),
        params,
      });

      const page = this.extractSessionPage(response.data);
      const sessions = page.records
        .map((record) => this.toAgentSession(record))
        .filter((session): session is AgentSession => session !== null);

      return {
        sessions,
        total: page.total ?? sessions.length,
        ...(page.cursor !== undefined ? { cursor: page.cursor } : {}),
      };
    } catch (error) {
      throw this.toServiceUnavailable("list sessions", error);
    }
  }

  async getSession(sessionId: string): Promise<AgentSession | null> {
    try {
      const response = await this.httpService.axiosRef.get(
        this.buildUrl(`/api/sessions/${encodeURIComponent(sessionId)}`),
        {
          headers: this.authHeaders(),
        }
      );

      const payload = this.unwrapContainer(response.data, ["session", "data"]);
      return this.toAgentSession(payload);
    } catch (error) {
      if (this.getHttpStatus(error) === 404) {
        return null;
      }

      throw this.toServiceUnavailable(`get session ${sessionId}`, error);
    }
  }

  async getMessages(
    sessionId: string,
    limit = DEFAULT_MESSAGE_LIMIT,
    before?: string
  ): Promise<AgentMessage[]> {
    const safeLimit = this.normalizeLimit(limit, DEFAULT_MESSAGE_LIMIT);
    const params: Record<string, number | string> = {
      sessionId,
      limit: safeLimit,
    };

    if (typeof before === "string" && before.length > 0) {
      params.before = before;
    }

    try {
      const response = await this.httpService.axiosRef.get(this.buildUrl("/api/messages"), {
        headers: this.authHeaders(),
        params,
      });

      return this.extractMessageRecords(response.data)
        .map((record) => this.toAgentMessage(record, sessionId))
        .filter((message): message is AgentMessage => message !== null);
    } catch (error) {
      throw this.toServiceUnavailable(`get messages for session ${sessionId}`, error);
    }
  }

  async injectMessage(sessionId: string, content: string): Promise<InjectResult> {
    try {
      const response = await this.httpService.axiosRef.post(
        this.buildUrl(`/api/sessions/${encodeURIComponent(sessionId)}/inject`),
        { content },
        {
          headers: this.authHeaders(),
        }
      );

      const payload = this.isRecord(response.data) ? response.data : {};

      return {
        accepted: typeof payload.accepted === "boolean" ? payload.accepted : true,
        ...(this.readString(payload.messageId) !== undefined
          ? { messageId: this.readString(payload.messageId) }
          : {}),
      };
    } catch (error) {
      throw this.toServiceUnavailable(`inject message into session ${sessionId}`, error);
    }
  }

  async pauseSession(sessionId: string): Promise<void> {
    try {
      await this.httpService.axiosRef.post(
        this.buildUrl(`/api/sessions/${encodeURIComponent(sessionId)}/pause`),
        {},
        {
          headers: this.authHeaders(),
        }
      );
    } catch (error) {
      throw this.toServiceUnavailable(`pause session ${sessionId}`, error);
    }
  }

  async resumeSession(sessionId: string): Promise<void> {
    try {
      await this.httpService.axiosRef.post(
        this.buildUrl(`/api/sessions/${encodeURIComponent(sessionId)}/resume`),
        {},
        {
          headers: this.authHeaders(),
        }
      );
    } catch (error) {
      throw this.toServiceUnavailable(`resume session ${sessionId}`, error);
    }
  }

  async killSession(sessionId: string, force = true): Promise<void> {
    try {
      await this.httpService.axiosRef.post(
        this.buildUrl(`/api/sessions/${encodeURIComponent(sessionId)}/kill`),
        { force },
        {
          headers: this.authHeaders(),
        }
      );
    } catch (error) {
      throw this.toServiceUnavailable(`kill session ${sessionId}`, error);
    }
  }

  async *streamMessages(sessionId: string): AsyncIterable<AgentMessage> {
    try {
      yield* this.sseBridge.streamSession(this.resolveBaseUrl(), sessionId, this.authHeaders());
    } catch (error) {
      throw this.toServiceUnavailable(`stream messages for session ${sessionId}`, error);
    }
  }

  async isAvailable(): Promise<boolean> {
    try {
      this.validateBaseUrl();
      this.validateToken();

      await this.httpService.axiosRef.get(this.buildUrl("/api/sessions"), {
        headers: this.authHeaders(),
        params: { limit: 1 },
      });

      return true;
    } catch {
      return false;
    }
  }

  private extractSessionPage(payload: unknown): {
    records: unknown[];
    total?: number;
    cursor?: string;
  } {
    if (Array.isArray(payload)) {
      return {
        records: payload,
        total: payload.length,
      };
    }

    if (!this.isRecord(payload)) {
      return {
        records: [],
      };
    }

    let records: unknown[] = [];
    if (Array.isArray(payload.sessions)) {
      records = payload.sessions;
    } else if (Array.isArray(payload.items)) {
      records = payload.items;
    } else if (Array.isArray(payload.data)) {
      records = payload.data;
    }

    const total = typeof payload.total === "number" ? payload.total : undefined;
    const cursor = this.readString(payload.cursor) ?? this.readString(payload.nextCursor);

    return {
      records,
      total,
      ...(cursor !== undefined ? { cursor } : {}),
    };
  }

  private extractMessageRecords(payload: unknown): unknown[] {
    if (Array.isArray(payload)) {
      return payload;
    }

    if (!this.isRecord(payload)) {
      return [];
    }

    if (Array.isArray(payload.messages)) {
      return payload.messages;
    }

    if (Array.isArray(payload.items)) {
      return payload.items;
    }

    if (Array.isArray(payload.data)) {
      return payload.data;
    }

    return [];
  }

  private unwrapContainer(payload: unknown, keys: string[]): unknown {
    if (!this.isRecord(payload)) {
      return payload;
    }

    for (const key of keys) {
      if (key in payload) {
        return payload[key];
      }
    }

    return payload;
  }

  private toAgentSession(record: unknown): AgentSession | null {
    if (!this.isRecord(record)) {
      return null;
    }

    const id =
      this.readString(record.id) ??
      this.readString(record.sessionId) ??
      this.readString(record.key);
    if (!id) {
      return null;
    }

    const createdAt = this.parseDate(record.createdAt ?? record.spawnedAt ?? record.startedAt);
    const updatedAt = this.parseDate(
      record.updatedAt ?? record.completedAt ?? record.lastActivityAt ?? record.endedAt,
      createdAt
    );

    const label =
      this.readString(record.label) ??
      this.readString(record.title) ??
      this.readString(record.name) ??
      undefined;

    const parentSessionId = this.readString(record.parentSessionId) ?? undefined;
    const metadata = this.toMetadata(record.metadata);

    return {
      id,
      providerId: this.providerId,
      providerType: this.providerType,
      ...(label !== undefined ? { label } : {}),
      status: this.toSessionStatus(this.readString(record.status)),
      ...(parentSessionId !== undefined ? { parentSessionId } : {}),
      createdAt,
      updatedAt,
      ...(metadata !== undefined ? { metadata } : {}),
    };
  }

  private toAgentMessage(value: unknown, fallbackSessionId?: string): AgentMessage | null {
    if (typeof value === "string") {
      const content = value.trim();
      if (content.length === 0 || fallbackSessionId === undefined) {
        return null;
      }

      return {
        id: randomUUID(),
        sessionId: fallbackSessionId,
        role: "assistant",
        content,
        timestamp: new Date(),
      };
    }

    let candidate: JsonRecord | null = null;

    if (this.isRecord(value) && this.isRecord(value.message)) {
      candidate = value.message;
    } else if (this.isRecord(value)) {
      candidate = value;
    }

    if (candidate === null) {
      return null;
    }

    const sessionId = this.readString(candidate.sessionId) ?? fallbackSessionId;
    if (!sessionId) {
      return null;
    }

    const content = this.extractMessageContent(
      candidate.content ?? candidate.text ?? candidate.message
    );
    if (content.length === 0) {
      return null;
    }

    const metadata = this.toMetadata(candidate.metadata);

    return {
      id: this.readString(candidate.id) ?? this.readString(candidate.messageId) ?? randomUUID(),
      sessionId,
      role: this.toMessageRole(this.readString(candidate.role) ?? this.readString(candidate.type)),
      content,
      timestamp: this.parseDate(candidate.timestamp ?? candidate.createdAt),
      ...(metadata !== undefined ? { metadata } : {}),
    };
  }

  private extractMessageContent(content: unknown): string {
    if (typeof content === "string") {
      return content.trim();
    }

    if (Array.isArray(content)) {
      const parts: string[] = [];

      for (const part of content) {
        if (typeof part === "string") {
          const trimmed = part.trim();
          if (trimmed.length > 0) {
            parts.push(trimmed);
          }
          continue;
        }

        if (!this.isRecord(part)) {
          continue;
        }

        const text = this.readString(part.text) ?? this.readString(part.content);
        if (text !== undefined && text.trim().length > 0) {
          parts.push(text.trim());
        }
      }

      return parts.join("\n\n").trim();
    }

    if (this.isRecord(content)) {
      const text = this.readString(content.text) ?? this.readString(content.content);
      return text?.trim() ?? "";
    }

    return "";
  }

  private toSessionStatus(status?: string): AgentSessionStatus {
    switch (status?.toLowerCase()) {
      case "active":
      case "running":
        return "active";
      case "paused":
        return "paused";
      case "completed":
      case "done":
      case "succeeded":
        return "completed";
      case "failed":
      case "error":
      case "killed":
      case "terminated":
      case "cancelled":
        return "failed";
      case "idle":
      case "pending":
      case "queued":
      default:
        return "idle";
    }
  }

  private toMessageRole(role?: string): AgentMessageRole {
    switch (role?.toLowerCase()) {
      case "assistant":
      case "agent":
        return "assistant";
      case "system":
        return "system";
      case "tool":
        return "tool";
      case "operator":
      case "user":
      default:
        return "user";
    }
  }

  private normalizeLimit(value: number, fallback: number): number {
    const normalized = Number.isFinite(value) ? Math.trunc(value) : fallback;
    if (normalized < 1) {
      return 1;
    }

    return Math.min(normalized, MAX_MESSAGE_LIMIT);
  }

  private parseDate(value: unknown, fallback = new Date()): Date {
    if (value instanceof Date) {
      return value;
    }

    if (typeof value === "string" || typeof value === "number") {
      const parsed = new Date(value);
      if (!Number.isNaN(parsed.getTime())) {
        return parsed;
      }
    }

    return fallback;
  }

  private toMetadata(value: unknown): Record<string, unknown> | undefined {
    if (this.isRecord(value)) {
      return value;
    }

    return undefined;
  }

  private resolveDisplayName(): string {
    const credentials = this.readCredentials();

    for (const key of DISPLAY_NAME_KEYS) {
      const value = this.readString(credentials[key]);
      if (value !== undefined) {
        return value;
      }
    }

    return this.config.name;
  }

  private resolveBaseUrl(): string {
    const configRecord = this.config as unknown as JsonRecord;
    const rawBaseUrl =
      this.readString(this.config.gatewayUrl) ?? this.readString(configRecord.baseUrl);

    if (rawBaseUrl === undefined) {
      throw new Error(`OpenClaw provider ${this.providerId} is missing gateway URL`);
    }

    try {
      const parsed = new URL(rawBaseUrl);
      return parsed.toString().replace(/\/$/u, "");
    } catch {
      throw new Error(`OpenClaw provider ${this.providerId} has invalid gateway URL`);
    }
  }

  private resolveApiToken(): string {
    const configRecord = this.config as unknown as JsonRecord;
    const credentials = this.readCredentials();

    const rawToken =
      this.readString(configRecord.apiToken) ??
      this.readString(configRecord.token) ??
      this.readString(configRecord.bearerToken) ??
      this.findFirstString(credentials, API_TOKEN_KEYS);

    if (rawToken === undefined) {
      throw new Error(`OpenClaw provider ${this.providerId} is missing apiToken credentials`);
    }

    try {
      return this.encryptionService.decryptIfNeeded(rawToken);
    } catch (error) {
      throw new Error(`Failed to decrypt API token: ${this.toErrorMessage(error)}`);
    }
  }

  private readCredentials(): JsonRecord {
    return this.isRecord(this.config.credentials) ? this.config.credentials : {};
  }

  private findFirstString(record: JsonRecord, keys: readonly string[]): string | undefined {
    for (const key of keys) {
      const value = this.readString(record[key]);
      if (value !== undefined) {
        return value;
      }
    }

    return undefined;
  }

  private authHeaders(extraHeaders: Record<string, string> = {}): Record<string, string> {
    return {
      Authorization: `Bearer ${this.resolveApiToken()}`,
      ...extraHeaders,
    };
  }

  private buildUrl(path: string): string {
    return new URL(path, `${this.resolveBaseUrl()}/`).toString();
  }

  private isRecord(value: unknown): value is JsonRecord {
    return typeof value === "object" && value !== null && !Array.isArray(value);
  }

  private readString(value: unknown): string | undefined {
    if (typeof value !== "string") {
      return undefined;
    }

    const trimmed = value.trim();
    return trimmed.length > 0 ? trimmed : undefined;
  }

  private getHttpStatus(error: unknown): number | undefined {
    if (typeof error !== "object" || error === null || !("response" in error)) {
      return undefined;
    }

    const response = (error as HttpErrorWithResponse).response;
    return typeof response?.status === "number" ? response.status : undefined;
  }

  private toServiceUnavailable(operation: string, error: unknown): ServiceUnavailableException {
    return new ServiceUnavailableException(
      `OpenClaw provider ${this.providerId} failed to ${operation}: ${this.toErrorMessage(error)}`
    );
  }

  private toErrorMessage(error: unknown): string {
    if (error instanceof Error) {
      return error.message;
    }

    return String(error);
  }
}