import { generateText } from 'ai';
import { createZhipu } from 'zhipu-ai-provider';

type AiWorkload = 'report' | 'extraction';
type AiProvider = 'zhipu';

type AiConfig = {
  provider: AiProvider;
  apiKey?: string;
  baseUrl: string;
  model: string;
  temperature: number;
};

type EnvSource = Record<string, string | undefined>;

type GetAiConfigOptions = {
  env?: EnvSource;
  warn?: (message: string) => void;
};

type AiGenerateInput = {
  model: unknown;
  system?: string;
  prompt: string;
  temperature: number;
  maxRetries?: number;
};

type AiGenerateOutput = {
  text: string;
};

type RunAiAnalysisOptions = GetAiConfigOptions & {
  workload?: AiWorkload;
  createModel?: (config: AiConfig) => unknown;
  generate?: (input: AiGenerateInput) => Promise<AiGenerateOutput>;
};

const CODING_API_BASE_URL = 'https://api.z.ai/api/coding/paas/v4';

let warnedIgnoredZhipuBaseUrl = false;

function envValue(name: string, env: EnvSource = process.env) {
  const value = env[name];
  if (!value) {
    return undefined;
  }

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

function parseTemperature(value: string | undefined) {
  const parsed = Number(value);
  if (!Number.isFinite(parsed)) {
    return 0.2;
  }

  return Math.min(Math.max(parsed, 0), 2);
}

function warnIgnoredZhipuBaseUrl(env: EnvSource, warn: (message: string) => void) {
  if (warnedIgnoredZhipuBaseUrl) {
    return;
  }

  const configuredBaseUrl = envValue('ZHIPU_BASE_URL', env);
  if (!configuredBaseUrl) {
    return;
  }

  warnedIgnoredZhipuBaseUrl = true;
  warn(
    `[AI SDK] ZHIPU_BASE_URL is ignored. The Coding API endpoint is hardcoded to ${CODING_API_BASE_URL}.`
  );
}

function defaultCreateModel(config: AiConfig) {
  const zhipu = createZhipu({
    apiKey: config.apiKey,
    baseURL: config.baseUrl
  });

  return zhipu(config.model);
}

async function defaultGenerate(input: AiGenerateInput): Promise<AiGenerateOutput> {
  const result = await generateText({
    model: input.model as never,
    system: input.system,
    prompt: input.prompt,
    temperature: input.temperature,
    maxRetries: input.maxRetries ?? 0
  });

  return { text: result.text };
}

export function getAiConfig(options?: GetAiConfigOptions) {
  return getReportAiConfig(options);
}

export function getReportAiConfig(options?: GetAiConfigOptions) {
  const env = options?.env ?? process.env;
  warnIgnoredZhipuBaseUrl(env, options?.warn ?? console.warn);

  return {
    provider: 'zhipu',
    apiKey: envValue('ZHIPU_API_KEY', env),
    baseUrl: CODING_API_BASE_URL,
    model: envValue('ZHIPU_MODEL', env) ?? 'glm-5',
    temperature: parseTemperature(envValue('AI_TEMPERATURE', env))
  } satisfies AiConfig;
}

export function getExtractionAiConfig(options?: GetAiConfigOptions) {
  return {
    ...getReportAiConfig(options),
    temperature: 0
  };
}

export function isAiConfigured(options?: GetAiConfigOptions) {
  const config = getReportAiConfig(options);
  return Boolean(config.apiKey);
}

export async function runAiAnalysis(prompt: string, systemPrompt?: string, options?: RunAiAnalysisOptions) {
  const workload = options?.workload ?? 'report';
  const config = workload === 'extraction'
    ? getExtractionAiConfig(options)
    : getReportAiConfig(options);

  if (!config.apiKey) {
    throw new Error('ZHIPU_API_KEY is required for AI workloads');
  }

  const createModel = options?.createModel ?? defaultCreateModel;
  const generate = options?.generate ?? defaultGenerate;
  const model = createModel(config);

  const result = await generate({
    model,
    system: systemPrompt,
    prompt,
    temperature: config.temperature,
    maxRetries: 0
  });

  const text = result.text.trim();
  if (!text) {
    throw new Error('AI SDK returned an empty response');
  }

  return {
    provider: config.provider,
    model: config.model,
    text
  };
}

export function __resetAiWarningsForTests() {
  warnedIgnoredZhipuBaseUrl = false;
}