import { createPiAgent, DEFAULT_LOCAL_MODEL_KEY, DEFAULT_MAX_NEW_TOKENS, LOCAL_MODELS } from "./piAgent.js";
import { PI_BUILTIN_TOOLS, PI_CLI_VERSION, PI_DEFAULT_TOOLS, PI_HELP_TEXT, PI_SLASH_COMMANDS, formatHotkeys } from "./piCliContract.js";

const ANSI_PATTERN = /\x1b\[[0-9;?]*[ -/]*[@-~]/g;

function stripAnsi(text) {
  return String(text).replace(ANSI_PATTERN, "");
}

function textFromContent(content) {
  if (typeof content === "string") return content;
  if (!Array.isArray(content)) return "";
  return content
    .filter((part) => part.type === "text")
    .map((part) => part.text)
    .join("\n");
}

function toolCallsFromMessage(message) {
  return Array.isArray(message.content) ? message.content.filter((part) => part.type === "toolCall") : [];
}

function formatToolCall(call) {
  const args = call.arguments || {};
  switch (call.name) {
    case "bash":
      return `$ ${args.command || ""}${args.timeout ? ` (timeout ${args.timeout}s)` : ""}`;
    case "write":
      return `write ${args.path || ""} (${String(args.content || "").length} bytes)`;
    case "read":
      return `read ${args.path || ""}${args.offset ? `:${args.offset}` : ""}${args.limit ? ` limit=${args.limit}` : ""}`;
    case "edit":
      return `edit ${args.path || ""} (${Array.isArray(args.edits) ? args.edits.length : 0} replacement(s))`;
    case "grep":
      return `grep ${args.pattern || ""} ${args.path || "."}`;
    case "find":
      return `find ${args.pattern || ""} ${args.path || "."}`;
    case "ls":
      return `ls ${args.path || "."}`;
    default:
      return `${call.name} ${JSON.stringify(args)}`;
  }
}

function modelLabel(mode) {
  if (mode === "mock") return "Deterministic test model";
  return LOCAL_MODELS[mode]?.id || LOCAL_MODELS[DEFAULT_LOCAL_MODEL_KEY].id;
}

function shortModelName(mode) {
  if (mode === "mock") return "mock";
  return LOCAL_MODELS[mode]?.name || LOCAL_MODELS[DEFAULT_LOCAL_MODEL_KEY].name;
}

export function createPiCli({ terminal, sandbox, nodes, params }) {
  let mode = "mock";
  let device = "wasm";
  let maxNewTokens = DEFAULT_MAX_NEW_TOKENS;
  let temperature = 0;
  let modelReady = false;
  let status = "Ready";
  let busy = false;
  let input = "";
  let renderedMessages = 0;
  let outputText = "";
  let sessionName = "untitled";
  let sessionId = crypto.randomUUID();
  let queuedLines = [];
  let agent = null;

  if (params.get("device")) device = params.get("device");
  if (params.get("tokens")) maxNewTokens = Number(params.get("tokens")) || DEFAULT_MAX_NEW_TOKENS;
  if (params.get("max_new_tokens")) maxNewTokens = Number(params.get("max_new_tokens")) || DEFAULT_MAX_NEW_TOKENS;
  if (LOCAL_MODELS[params.get("model")]) mode = params.get("model");
  if (LOCAL_MODELS[params.get("mode")]) mode = params.get("mode");
  if (params.get("mode") === "mock") mode = "mock";
  if (mode !== "mock" && !LOCAL_MODELS[mode]) mode = DEFAULT_LOCAL_MODEL_KEY;
  if (!navigator.gpu && device === "webgpu") device = "wasm";
  modelReady = mode === "mock";

  function write(text) {
    const value = String(text);
    outputText += stripAnsi(value).replace(/\r/g, "");
    if (outputText.length > 250000) outputText = outputText.slice(-200000);
    terminal.write(value);
  }

  function writeln(text = "") {
    write(`${text}\n`);
  }

  function setStatus(next) {
    status = next;
    nodes.status.textContent = next;
  }

  function setModelStatus(next) {
    nodes.modelStatus.textContent = next;
    nodes.modelLabel.textContent = modelLabel(mode);
  }

  function setSandboxStatus(next) {
    nodes.sandboxStatus.textContent = next;
  }

  function createAgent() {
    const next = createPiAgent({
      sandbox,
      modelMode: () => mode,
      device: () => device,
      maxTokens: () => maxNewTokens,
      temperature: () => temperature,
      onModelStatus: setModelStatus,
    });
    next.subscribe((event) => {
      switch (event.type) {
        case "agent_start":
          setStatus("Agent running");
          break;
        case "tool_execution_start":
          writeln(`\x1b[2m[running ${event.toolName}]\x1b[22m`);
          break;
        case "message_end":
          renderNewMessages();
          break;
        case "agent_end":
          setStatus("Ready");
          break;
        default:
          break;
      }
    });
    return next;
  }

  function resetAgent() {
    agent?.abort();
    agent = createAgent();
    renderedMessages = 0;
  }

  async function bootSandbox({ quiet = false } = {}) {
    if (!quiet) writeln("\x1b[2mBooting WebContainer sandbox...\x1b[22m");
    await sandbox.boot();
    if (!quiet) writeln("\x1b[2mSandbox ready.\x1b[22m");
  }

  function showGate(message = "Ready.") {
    nodes.gateStatus.textContent = message;
    nodes.modelGate.classList.remove("hidden");
  }

  function hideGate() {
    nodes.modelGate.classList.add("hidden");
  }

  async function loadModel() {
    if (mode === "mock") {
      modelReady = true;
      setModelStatus("Deterministic test model");
      hideGate();
      return;
    }
    busy = true;
    setStatus("Loading model");
    nodes.gateStatus.textContent = "Booting sandbox...";
    writeln(`\x1b[2mPreparing ${modelLabel(mode)} on ${device}...\x1b[22m`);
    try {
      await bootSandbox({ quiet: true });
      nodes.gateStatus.textContent = "Downloading model...";
      await agent.preloadModel();
      modelReady = true;
      setModelStatus("Model ready");
      nodes.gateStatus.textContent = "Model ready.";
      hideGate();
      writeln("\x1b[32mModel ready.\x1b[0m");
    } catch (error) {
      const message = error.stack || error.message || String(error);
      setModelStatus("Model error");
      nodes.gateStatus.textContent = message;
      writeln(`\x1b[31m${message}\x1b[0m`);
    } finally {
      busy = false;
      setStatus("Ready");
      writePrompt();
    }
  }

  function writeStartup() {
    writeln(`pi - AI coding assistant with read, bash, edit, write tools`);
    writeln(`version ${PI_CLI_VERSION} | web terminal ${terminal.engine} | cwd /workspace`);
    writeln(`shortcuts: /hotkeys | /model | /settings | /session | /help`);
    writeln(`loaded AGENTS.md: none | prompt templates: none | skills: none | extensions: none`);
    writeln(`tools: ${PI_DEFAULT_TOOLS.join(", ")} (read-only extras available: grep, find, ls)`);
    if (!modelReady) {
      writeln(`model: ${modelLabel(mode)} is not downloaded. Use the setup dialog or /model mock.`);
    } else {
      writeln(`model: ${modelLabel(mode)}`);
    }
    writeln();
  }

  function footer() {
    return `cwd /workspace | session ${sessionName} | model ${shortModelName(mode)} | ${maxNewTokens} max tokens | ${status}`;
  }

  function writePrompt() {
    if (busy) return;
    writeln(`\x1b[2m${footer()}\x1b[22m`);
    write("> ");
    terminal.focus();
  }

  function renderNewMessages() {
    const messages = agent.state.messages;
    while (renderedMessages < messages.length) {
      const message = messages[renderedMessages];
      renderedMessages += 1;
      if (message.role === "user") continue;
      if (message.role === "toolResult") {
        const text = textFromContent(message.content);
        const label = message.isError ? `[tool error: ${message.toolName}]` : `[tool: ${message.toolName}]`;
        writeln(`\x1b[36m${label}\x1b[0m`);
        if (text) writeln(text);
        writeln();
        continue;
      }
      const toolCalls = toolCallsFromMessage(message);
      if (toolCalls.length > 0) {
        writeln("\x1b[35mUsing pi tools:\x1b[0m");
        for (const call of toolCalls) writeln(`  ${formatToolCall(call)}`);
        writeln();
        continue;
      }
      const text = textFromContent(message.content);
      if (text) {
        writeln("\x1b[32mpi\x1b[0m");
        writeln(text);
        writeln();
      }
    }
  }

  async function runBashLine(command, sendToModel) {
    busy = true;
    setStatus("Running command");
    try {
      await bootSandbox({ quiet: true });
      writeln(`$ ${command}`);
      const result = await sandbox.bash(command, 120);
      if (result.output) writeln(result.output);
      writeln(`exit ${result.exitCode}`);
      if (sendToModel) {
        await promptAgent(`Command output from \`${command}\`:\n${result.output || "(no output)"}\nexit ${result.exitCode}`);
      }
    } catch (error) {
      writeln(`\x1b[31m${error.stack || error.message || String(error)}\x1b[0m`);
    } finally {
      busy = false;
      setStatus("Ready");
      if (!sendToModel) writePrompt();
    }
  }

  async function promptAgent(prompt) {
    if (mode !== "mock" && !modelReady) {
      writeln("Download the selected local model before sending, or use /model mock.");
      showGate("Download the selected model before sending, or use the test model.");
      writePrompt();
      return;
    }

    busy = true;
    setStatus("Agent running");
    try {
      await bootSandbox({ quiet: true });
      await agent.prompt(prompt);
    } catch (error) {
      writeln(`\x1b[31m${error.stack || error.message || String(error)}\x1b[0m`);
    } finally {
      busy = false;
      setStatus("Ready");
      const next = queuedLines.shift();
      if (next) {
        writeln(`\x1b[2m[dequeued] ${next}\x1b[22m`);
        await handleLine(next, { fromQueue: true });
      } else {
        writePrompt();
      }
    }
  }

  function printModels() {
    writeln("Available browser-local models:");
    for (const [key, value] of Object.entries(LOCAL_MODELS)) {
      writeln(`  ${key.padEnd(12)} ${value.id}`);
    }
    writeln("  mock         deterministic test model");
    writeln("Use /model <key> to switch. Non-mock models run in this browser through Transformers.js.");
  }

  function printSession() {
    writeln(`Session`);
    writeln(`  id: ${sessionId}`);
    writeln(`  name: ${sessionName}`);
    writeln(`  messages: ${agent.state.messages.length}`);
    writeln(`  cwd: /workspace`);
    writeln(`  storage: browser memory`);
  }

  async function handleSlash(line) {
    const [command, ...rest] = line.trim().split(/\s+/);
    const argText = rest.join(" ");
    switch (command) {
      case "/help":
        writeln(PI_HELP_TEXT);
        break;
      case "/hotkeys":
        writeln(formatHotkeys());
        break;
      case "/model":
        if (!argText) {
          printModels();
          break;
        }
        if (argText === "mock" || LOCAL_MODELS[argText]) {
          mode = argText;
          modelReady = mode === "mock";
          resetAgent();
          setModelStatus(modelReady ? "Deterministic test model" : "Model idle");
          writeln(`model: ${modelLabel(mode)}`);
          if (!modelReady) showGate("Download the selected model before sending.");
          else hideGate();
        } else {
          writeln(`Unknown model: ${argText}`);
          printModels();
        }
        break;
      case "/settings":
        if (argText.startsWith("device=")) {
          device = argText.slice("device=".length) || device;
          modelReady = mode === "mock";
          resetAgent();
        } else if (argText.startsWith("tokens=")) {
          maxNewTokens = Number(argText.slice("tokens=".length)) || maxNewTokens;
        } else if (argText.startsWith("temperature=")) {
          temperature = Number(argText.slice("temperature=".length)) || 0;
        }
        writeln(`Settings`);
        writeln(`  device: ${device}`);
        writeln(`  max tokens: ${maxNewTokens}`);
        writeln(`  temperature: ${temperature}`);
        writeln(`  transport: browser-local Transformers.js`);
        break;
      case "/session":
        printSession();
        break;
      case "/new":
        resetAgent();
        await sandbox.reset();
        sessionId = crypto.randomUUID();
        sessionName = "untitled";
        writeln("Started a new browser session and reset the WebContainer workspace.");
        break;
      case "/name":
        sessionName = argText || "untitled";
        writeln(`Session name: ${sessionName}`);
        break;
      case "/tools":
        writeln(`Default tools: ${PI_DEFAULT_TOOLS.join(", ")}`);
        writeln(`Built-in tools: ${PI_BUILTIN_TOOLS.join(", ")}`);
        break;
      case "/clear":
        terminal.clear();
        outputText = "";
        writeStartup();
        break;
      case "/login":
      case "/logout":
        writeln("This web port runs a local browser model, so provider login is not required. Use /model to switch local planners.");
        break;
      case "/resume":
      case "/tree":
      case "/fork":
      case "/clone":
      case "/compact":
      case "/copy":
      case "/export":
      case "/share":
      case "/reload":
      case "/changelog":
      case "/scoped-models":
        writeln(`${command} is recognized from Pi CLI. In this static browser build it is represented in-memory; full filesystem-backed session management is a follow-up target.`);
        break;
      case "/quit":
        writeln("Close this browser tab to quit the web terminal.");
        break;
      case "/commands":
        writeln(PI_SLASH_COMMANDS.join("\n"));
        break;
      default:
        writeln(`Unknown command: ${command}`);
        writeln("Type /help or /commands.");
        break;
    }
  }

  async function handleLine(line, { fromQueue = false } = {}) {
    const trimmed = line.trim();
    if (!trimmed) {
      writePrompt();
      return;
    }
    if (busy && !fromQueue) {
      queuedLines.push(line);
      writeln(`\x1b[2m[queued] ${line}\x1b[22m`);
      return;
    }
    if (trimmed.startsWith("/")) {
      await handleSlash(trimmed);
      writePrompt();
      return;
    }
    if (trimmed.startsWith("!!")) {
      await runBashLine(trimmed.slice(2).trim(), false);
      return;
    }
    if (trimmed.startsWith("!")) {
      await runBashLine(trimmed.slice(1).trim(), true);
      return;
    }
    await promptAgent(line);
  }

  function redrawInput(nextInput) {
    write("\r\x1b[2K> ");
    input = nextInput;
    write(input);
  }

  function handleData(data) {
    for (const char of data) {
      if (char === "\r") {
        const submitted = input;
        input = "";
        writeln();
        void handleLine(submitted);
      } else if (char === "\u007f") {
        if (input.length > 0) {
          input = input.slice(0, -1);
          write("\b \b");
        }
      } else if (char === "\x03") {
        if (busy) {
          agent.abort();
          writeln("^C");
          setStatus("Aborted");
        } else if (input) {
          redrawInput("");
        } else {
          writeln("^C");
          writeln("Use /quit or close this browser tab to exit.");
          writePrompt();
        }
      } else if (char === "\x1b") {
        if (busy) agent.abort();
      } else if (char >= " " && char !== "\x7f") {
        input += char;
        write(char);
      }
    }
  }

  nodes.confirmLoadModel.addEventListener("click", async () => {
    device = nodes.gateDevice.value;
    await loadModel();
  });
  nodes.useTestModel.addEventListener("click", () => {
    mode = "mock";
    modelReady = true;
    resetAgent();
    setModelStatus("Deterministic test model");
    hideGate();
    writeln("model: deterministic test model");
    writePrompt();
  });

  resetAgent();
  setStatus("Ready");
  setSandboxStatus("Not booted");
  setModelStatus(modelReady ? "Deterministic test model" : "Model idle");
  nodes.gateDevice.value = device;
  if (modelReady || params.get("setup") === "skip") hideGate();
  else showGate("Ready.");

  terminal.onData(handleData);
  writeStartup();
  writePrompt();

  return {
    loadModel,
    handleLine,
    get outputText() {
      return outputText;
    },
    get transcript() {
      return agent.state.messages
        .map((message) => {
          if (message.role === "toolResult") return `TOOL ${message.toolName}\n${textFromContent(message.content)}`;
          return `${message.role.toUpperCase()}\n${textFromContent(message.content)}`;
        })
        .join("\n\n");
    },
    get modelReady() {
      return modelReady;
    },
    get status() {
      return status;
    },
    get mode() {
      return mode;
    },
  };
}