import type {
  AIProvider,
  AIProviderConfig,
  AIHealthResult,
  GenerateTextRequest,
  GenerateTextResponse,
} from "../types";
import { isModelAvailable, resolveModelName } from "../model-resolve";
import { redactError, redactUrl } from "../types";

export function createOllamaProvider(): AIProvider {
  return {
    type: "ollama",
    async healthCheck(config: AIProviderConfig): Promise<AIHealthResult> {
      const start = Date.now();
      try {
        const res = await fetch(`${config.baseUrl}/api/tags`, {
          signal: AbortSignal.timeout(5000),
        });
        const latencyMs = Date.now() - start;
        if (!res.ok) {
          return {
            status: "offline",
            provider: "ollama",
            model: config.model,
            latencyMs,
            lastSuccessAt: null,
            lastFailureAt: new Date().toISOString(),
            lastError: redactError(`HTTP ${res.status}`),
            baseUrlSafe: redactUrl(config.baseUrl),
            contextLength: null,
            memoryUsageMb: null,
            modelsAvailable: [],
          };
        }
        const data = await res.json();
        const models = (data.models ?? []).map(
          (m: { name: string }) => m.name
        );
        const modelReady = isModelAvailable(config.model, models);
        const resolvedModel = resolveModelName(config.model, models);
        return {
          status:
            models.length === 0
              ? "degraded"
              : modelReady || resolvedModel
                ? "online"
                : "degraded",
          provider: "ollama",
          model: resolvedModel ?? config.model,
          latencyMs,
          lastSuccessAt: new Date().toISOString(),
          lastFailureAt: modelReady ? null : new Date().toISOString(),
          lastError: modelReady
            ? null
            : models.length === 0
              ? "No models installed in Ollama"
              : `Model "${config.model}" not found. Available: ${models.slice(0, 5).join(", ")}`,
          baseUrlSafe: redactUrl(config.baseUrl),
          contextLength: null,
          memoryUsageMb: null,
          modelsAvailable: models,
        };
      } catch (e) {
        return {
          status: "offline",
          provider: "ollama",
          model: config.model,
          latencyMs: Date.now() - start,
          lastSuccessAt: null,
          lastFailureAt: new Date().toISOString(),
          lastError: redactError(e instanceof Error ? e.message : "Connection failed"),
          baseUrlSafe: redactUrl(config.baseUrl),
          contextLength: null,
          memoryUsageMb: null,
          modelsAvailable: [],
        };
      }
    },
    async listModels(config: AIProviderConfig) {
      const res = await fetch(`${config.baseUrl}/api/tags`, {
        signal: AbortSignal.timeout(5000),
      });
      if (!res.ok) return [];
      const data = await res.json();
      return (data.models ?? []).map((m: { name: string }) => m.name);
    },
    async generateText(
      config: AIProviderConfig,
      req: GenerateTextRequest
    ): Promise<GenerateTextResponse> {
      const start = Date.now();
      const requested = req.model || config.model;
      let model = requested;

      const tagsRes = await fetch(`${config.baseUrl}/api/tags`, {
        signal: AbortSignal.timeout(5000),
      });
      if (tagsRes.ok) {
        const tagsData = await tagsRes.json();
        const models = (tagsData.models ?? []).map(
          (m: { name: string }) => m.name as string
        );
        const resolved = resolveModelName(requested, models);
        if (resolved) {
          model = resolved;
        } else if (models.length === 0) {
          throw new Error(`Ollama error: no models installed`);
        }
        if (model !== requested) {
          console.error(
            `[adventureos-ai] ollama: resolved model "${requested}" -> "${model}"`
          );
        }
      }

      const res = await fetch(`${config.baseUrl}/api/generate`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          model,
          prompt: req.prompt,
          system: req.system,
          stream: false,
          format: req.format === "json" ? "json" : undefined,
          options: {
            temperature: req.temperature ?? config.temperature,
            num_predict: req.maxTokens ?? config.maxTokens,
          },
        }),
        signal: AbortSignal.timeout(req.timeoutMs ?? config.timeoutMs),
      });
      if (!res.ok) {
        const body = await res.text().catch(() => "");
        throw new Error(
          `Ollama error: HTTP ${res.status}${body ? ` — ${body.slice(0, 200)}` : ""}`
        );
      }
      const data = await res.json();
      return {
        text: data.response ?? "",
        model,
        latencyMs: Date.now() - start,
      };
    },
  };
}