/**
 * OpenCode v2 Plugin: Auto-discover models from OpenAI-compatible endpoints.
 *
 * Config-driven: reads providers from opencode.jsonc (project or global).
 * For every provider whose `package` contains "openai-compatible" (and which
 * has opted in via `settings.discover_models === true`, or no opt-in flag set
 * for backward compat), fetches /models and registers them under that provider.
 * Creates the provider if it does not exist yet.
 */

import { Plugin, Model } from "@opencode/plugin";

function parseJsonc(text: string): any {
  try { return JSON.parse(text); } catch {}
  let s = text.replace(/\/\/.*$/gm, "").replace(/\/\*[\s\S]*?\*\//g, "");
  s = s.replace(/,\s*([}\]])/g, "$1");
  return JSON.parse(s);
}

function readConfigProviders(): Record<string, any> {
  const fs = require("node:fs");
  const path = require("node:path");
  const os = require("node:os");
  const candidates = [
    path.join(process.cwd(), "opencode.jsonc"),
    path.join(process.cwd(), "opencode.json"),
    path.join(os.homedir(), ".config", "opencode", "opencode.jsonc"),
  ];
  const merged: Record<string, any> = {};
  for (const c of candidates) {
    try {
      if (!fs.existsSync(c)) continue;
      const cfg = parseJsonc(fs.readFileSync(c, "utf8"));
      const provs = cfg?.providers || cfg?.provider;
      if (provs && typeof provs === "object") {
        for (const [k, v] of Object.entries(provs)) {
          if (!merged[k]) merged[k] = v;
        }
      }
    } catch {}
  }
  return merged;
}

interface Target { id: string; baseURL: string; apiKey: string; }

function isOpenAICompatible(pkg: unknown): boolean {
  return typeof pkg === "string" && pkg.toLowerCase().includes("openai-compatible");
}

function hasOptIn(settings: Record<string, unknown>): boolean {
  // backward compat: if no discover_models flag present, default to enabled
  if (settings.discover_models === undefined && settings.modelsDiscovery === undefined) return true;
  if (settings.discover_models === true) return true;
  const md = settings.modelsDiscovery;
  if (md && typeof md === "object" && (md as Record<string, unknown>).enabled === true) return true;
  if (settings.discover_models === false) return false;
  return false;
}

async function fetchModels(baseURL: string, apiKey: string): Promise<Model.Info[]> {
  const headers: Record<string, string> = { "Content-Type": "application/json" };
  if (apiKey) headers["Authorization"] = `Bearer ${apiKey}`;
  const res = await fetch(`${baseURL}/models`, { headers });
  if (!res.ok) throw new Error(`HTTP ${res.status} from ${baseURL}/models`);
  const json = await res.json();
  const rawModels = (json.data || []) as Array<Record<string, unknown>>;
  return rawModels.map((m) => {
    const modelId = typeof m.id === "string" ? m.id : String(m.id);
    const contextLength = typeof m.context_length === "number" ? m.context_length : 131072;
    const maxTokens = typeof m.max_tokens === "number" ? m.max_tokens : 32768;
    const inputMods = Array.isArray(m.input_modalities) ? (m.input_modalities as string[]) : ["text"];
    const outputMods = Array.isArray(m.output_modalities) ? (m.output_modalities as string[]) : ["text"];
    return {
      id: modelId, modelID: modelId, providerID: "", name: modelId,
      capabilities: { tools: true, input: inputMods, output: outputMods },
      variants: [], cost: [{ input: 0, output: 0, cache: { read: 0, write: 0 } }],
      limit: { context: contextLength, output: Math.min(maxTokens, contextLength) },
      time: { released: Math.floor(Date.now() / 1000) },
      status: "active" as const, enabled: true,
    } as unknown as Model.Info;
  });
}

export default Plugin.define({
  id: "opencode.openai-compatible-model-discovery",
  async setup(ctx) {
    const providers = readConfigProviders();
    console.error("[openai-discovery] config providers:", Object.keys(providers));
    const targets: Target[] = [];
    for (const [id, info] of Object.entries(providers)) {
      const p = info as Record<string, unknown>;
      if (!isOpenAICompatible(p.package)) continue;
      const settings = p.settings && typeof p.settings === "object" ? (p.settings as Record<string, unknown>) : {};
      if (!hasOptIn(settings)) continue;
      const baseURL = typeof settings.baseURL === "string" ? settings.baseURL : undefined;
      if (!baseURL) { console.warn(`[openai-discovery] Provider "${id}" has no settings.baseURL — skipping`); continue; }
      const apiKey = typeof settings.apiKey === "string" ? settings.apiKey : "";
      targets.push({ id, baseURL, apiKey });
    }
    if (targets.length === 0) {
      console.log("[openai-discovery] No opted-in openai-compatible providers found — nothing to do");
      return;
    }
    for (const target of targets) {
      try {
        const models = await fetchModels(target.baseURL, target.apiKey);
        for (const m of models) (m as { providerID: string }).providerID = target.id;
        await ctx.provider.transform((editor) => {
          const source = editor.get(target.id);
          if (source) {
            const existing = [...source.models.values()];
            const existingIDs = new Set(existing.map((model) => String(model.id)));
            const merged = [...existing, ...models.filter((m) => !existingIDs.has(String(m.id)))];
            editor.models.set(target.id, merged);
          } else {
            editor.add({ info: { id: target.id, name: target.id, activation: "enabled" as const, package: "aisdk:@ai-sdk/openai-compatible", settings: { baseURL: target.baseURL, apiKey: target.apiKey } } as never, models });
          }
        });
        console.log(`[openai-discovery] Registered ${models.length} models in provider "${target.id}"`);
      } catch (error) {
        console.error(`[openai-discovery] Failed to discover models for "${target.id}": ${error instanceof Error ? error.message : String(error)}`);
      }
    }
  },
});