function quoteToml(value) {
  return `"${String(value).replace(/\\/g, "\\\\").replace(/"/g, '\\"')}"`;
}

function json(value) {
  return JSON.stringify(value, null, 2);
}

function safeContextWindow(modelData) {
  return (
    modelData?.gguf?.context_length ??
    modelData?.config?.max_position_embeddings ??
    modelData?.transformersInfo?.max_position_embeddings ??
    128000
  );
}

function safeMaxTokens(modelData) {
  const contextWindow = safeContextWindow(modelData);
  return Math.min(Math.max(4096, Math.floor(contextWindow / 8)), 32768);
}

function agentDisplayName(modelData) {
  return modelData.repoId.split("/").pop() ?? modelData.repoId;
}

export const AGENTS = {
  pi: {
    apiFormats: ["openai-completions"]
  },
  openclaw: {
    apiFormats: ["openai-completions", "openai-responses", "anthropic-messages"]
  },
  opencode: {
    apiFormats: ["openai-completions"]
  },
  codex: {
    apiFormats: ["openai-responses"]
  },
  claude: {
    apiFormats: ["anthropic-messages"]
  }
};

export function assertAgentCompatibility(agent, runtime) {
  const descriptor = AGENTS[agent];
  if (!descriptor) {
    throw new Error(`Unknown agent "${agent}".`);
  }

  if (!descriptor.apiFormats.includes(runtime.apiFormat)) {
    throw new Error(
      [
        `Agent "${agent}" is incompatible with runtime "${runtime.key}".`,
        `Agent "${agent}" needs one of: ${descriptor.apiFormats.join(", ")}.`,
        `Runtime "${runtime.key}" exposes: ${runtime.apiFormat}.`
      ].join(" ")
    );
  }
}

function renderPiArtifacts({ baseUrl, servedModelId, modelData }) {
  const content = {
    providers: {
      "hf-local": {
        baseUrl,
        api: "openai-completions",
        apiKey: "none",
        models: [
          {
            id: servedModelId,
            contextWindow: safeContextWindow(modelData)
          }
        ]
      }
    }
  };

  return {
    files: [
      {
        name: "pi.models.json",
        targetPath: "~/.pi/agent/models.json",
        content: json(content)
      }
    ],
    cliCommands: []
  };
}

function renderOpenClawArtifacts({ baseUrl, servedModelId, modelData, runtime }) {
  const primaryRef = `hf-local/${servedModelId}`;
  const configFragment = {
    agents: {
      defaults: {
        model: {
          primary: primaryRef
        },
        models: {
          [primaryRef]: {
            alias: agentDisplayName(modelData)
          }
        }
      }
    },
    models: {
      mode: "merge",
      providers: {
        "hf-local": {
          baseUrl,
          apiKey: "none",
          api: runtime.apiFormat,
          models: [
            {
              id: servedModelId,
              name: agentDisplayName(modelData),
              reasoning: false,
              input: ["text"],
              cost: {
                input: 0,
                output: 0,
                cacheRead: 0,
                cacheWrite: 0
              },
              contextWindow: safeContextWindow(modelData),
              maxTokens: safeMaxTokens(modelData)
            }
          ]
        }
      }
    }
  };

  const cliCommands = [];

  if (runtime.apiFormat === "openai-completions") {
    const onboardCommand = [
      "openclaw onboard --non-interactive \\",
      "  --auth-choice custom-api-key \\",
      `  --custom-base-url "${baseUrl}" \\`,
      `  --custom-model-id "${servedModelId}" \\`,
      '  --custom-api-key "hf-local" \\',
      '  --secret-input-mode plaintext \\',
      '  --custom-compatibility openai \\',
      "  --accept-risk"
    ].join("\n");

    cliCommands.push({
      title: "openclaw onboard",
      content: onboardCommand
    });
  }

  return {
    files: [
      {
        name: "openclaw.config.json",
        targetPath: "merge into your OpenClaw config or agent models.json",
        content: json(configFragment)
      }
    ],
    cliCommands
  };
}

function renderOpenCodeArtifacts({ baseUrl, servedModelId, modelData }) {
  const contextWindow = safeContextWindow(modelData);
  const outputTokens = safeMaxTokens(modelData);
  const content = {
    $schema: "https://opencode.ai/config.json",
    provider: {
      "hf-local": {
        npm: "@ai-sdk/openai-compatible",
        name: "HF Local",
        options: {
          baseURL: baseUrl,
          apiKey: "none"
        },
        models: {
          [servedModelId]: {
            name: agentDisplayName(modelData),
            limit: {
              context: contextWindow,
              output: outputTokens
            }
          }
        }
      }
    },
    model: `hf-local/${servedModelId}`
  };

  return {
    files: [
      {
        name: "opencode.json",
        targetPath: "~/.config/opencode/opencode.json",
        content: json(content)
      }
    ],
    cliCommands: []
  };
}

function renderCodexArtifacts({ baseUrl, servedModelId }) {
  const content = [
    'model_provider = "hf_local"',
    `model = ${quoteToml(servedModelId)}`,
    "",
    "[model_providers.hf_local]",
    'name = "HF Local Responses"',
    `base_url = ${quoteToml(baseUrl)}`,
    'wire_api = "responses"',
    "requires_openai_auth = false",
    "supports_websockets = false"
  ].join("\n");

  return {
    files: [
      {
        name: "codex.config.toml",
        targetPath: "~/.codex/config.toml",
        content
      }
    ],
    cliCommands: []
  };
}

function renderClaudeArtifacts({ baseUrl, servedModelId }) {
  const content = {
    model: servedModelId,
    env: {
      ANTHROPIC_BASE_URL: baseUrl,
      ANTHROPIC_MODEL: servedModelId,
      ANTHROPIC_CUSTOM_MODEL_OPTION: servedModelId,
      ANTHROPIC_CUSTOM_MODEL_OPTION_NAME: "HF Local",
      ANTHROPIC_CUSTOM_MODEL_OPTION_DESCRIPTION: "Gateway-routed Hugging Face local model"
    }
  };

  return {
    files: [
      {
        name: "claude.settings.json",
        targetPath: "~/.claude/settings.json",
        content: json(content)
      }
    ],
    cliCommands: []
  };
}

export function buildAgentArtifacts({ agent, runtime, baseUrl, servedModelId, modelData }) {
  assertAgentCompatibility(agent, runtime);

  if (!baseUrl) {
    throw new Error(`Agent "${agent}" requires a base URL, but runtime "${runtime.key}" does not define one. Pass --base-url.`);
  }

  if (agent === "pi") {
    return renderPiArtifacts({ baseUrl, servedModelId, modelData });
  }
  if (agent === "openclaw") {
    return renderOpenClawArtifacts({ baseUrl, servedModelId, modelData, runtime });
  }
  if (agent === "opencode") {
    return renderOpenCodeArtifacts({ baseUrl, servedModelId, modelData });
  }
  if (agent === "codex") {
    return renderCodexArtifacts({ baseUrl, servedModelId });
  }
  if (agent === "claude") {
    return renderClaudeArtifacts({ baseUrl, servedModelId });
  }

  throw new Error(`Unknown agent "${agent}".`);
}