/**
 * Feishu @bot trigger → AgentRun lifecycle (streaming).
 *
 * Sends a "processing" card immediately, patches it with text deltas + tool
 * status as the agent streams, then replaces it with a final status card on
 * completion. Throttled to ~1 patch/sec to avoid spamming the Feishu API.
 *
 * ADR-0001..0003, 0017: chat→project binding, permission gate, lock,
 * provider-bound session, transcript continuity, ADR-0003-authorized reads.
 */
import type { PrismaClient } from "@prisma/client";
import type { FastifyBaseLogger } from "fastify";
import { sendText, sendTextMessage, patchTextMessage, reactToMessage, downloadMessageFile, sendFile, type FeishuRuntime, type MessageReceiveEvent } from "./client.js";
import type { ModelRegistry } from "../agent/models.js";
import { runAgent, type ProjectContext } from "../agent/runner.js";
import { acquireLock, currentLockRunId, releaseLock } from "../lock.js";
import { canTriggerAgent, canTriggerRole } from "../permission.js";
import { transcriptPath } from "../agent/transcript.js";
import { writeAudit } from "../audit.js";

interface TriggerDeps {
  readonly prisma: PrismaClient;
  readonly models: ModelRegistry;
  readonly logger: FastifyBaseLogger;
}

/**
 * Build the message handler. Returns a function suitable for the lark
 * `im.message.receive_v1` event. The handler is async and long-running (the
 * agent run is the long leg); the lock guarantees one run per project at a time.
 */
export function makeTriggerHandler(deps: TriggerDeps) {
  return async (event: MessageReceiveEvent, rt: FeishuRuntime): Promise<void> => {
    const msg = event.message;
    const sender = event.sender;
    void sender; // sender→user mapping is OPEN (principal sub-typology)

    // Dedup: the lark ws client redelivers at-least-once. A duplicate event
    // would spawn a second AgentRun — the lock would refuse it, but a FAILED
    // run row + a busy reply would leak. Record the event_id up front; if it
    // already exists, this is a redelivery → stop.
    const eventId = event.header?.event_id;
    if (eventId !== undefined && eventId !== "") {
      const existing = await deps.prisma.feishuEventReceipt.findUnique({
        where: { eventId },
        select: { id: true },
      });
      if (existing !== null) {
        deps.logger.debug({ eventId }, "feishu trigger: duplicate event, skipping");
        return;
      }
      await deps.prisma.feishuEventReceipt.create({
        data: {
          eventId,
          eventType: event.header?.event_type ?? "im.message.receive_v1",
          messageId: msg.message_id,
        },
      });
    }

    // Only react to text, file, or image messages in group chats.
    if (msg.message_type !== "text" && msg.message_type !== "file" && msg.message_type !== "image") return;
    const chatId = msg.chat_id;
    if (chatId === "") return;

    // ADR-0001: resolve chat → project. Unknown chat ⇒ not a project group.
    const binding = await deps.prisma.projectGroupBinding.findUnique({
      where: { chatId },
      select: { projectId: true },
    });
    if (binding === null) {
      deps.logger.debug({ chatId }, "feishu trigger: chat not bound to any project");
      return;
    }
    const projectId = binding.projectId;
    // ADR-0004: triggerAgent requires edit on the project. principal=sender
 // open_id (sub-typology OPEN — pragmatic choice, see permission.ts).
    const senderOpenId = event.sender.sender_id.open_id ?? "";
    if (senderOpenId !== "") {
      const perm = await canTriggerAgent(deps.prisma, projectId, senderOpenId);
      if (!perm.allowed) {
        deps.logger.info({ projectId, senderOpenId, reason: perm.reason }, "feishu trigger: permission denied");
        await writeAudit(deps.prisma, { projectId, actorUserId: senderOpenId || undefined, action: "trigger.denied", metadata: { reason: perm.reason } });
        await sendText(rt, chatId, "无权限触发。");
        return;
      }
    }

    let cleanPrompt: string | null = null;
    let downloadedFiles: string[] = [];
    if (msg.message_type === "text") {
      cleanPrompt = extractPrompt(msg);
    } else if (msg.message_type === "file" || msg.message_type === "image") {
      // Download the file/image to the workspace, build a prompt around it.
      const project = await deps.prisma.project.findUnique({
        where: { id: projectId },
        select: { workspaceDir: true },
      });
      if (project === null) return;
      try {
        const content = JSON.parse(msg.content) as { file_key?: string; image_key?: string };
        const key = content.file_key ?? content.image_key ?? "";
        if (key !== "") {
          const fileName = `${msg.message_type}-${Date.now()}.${msg.message_type === "image" ? "png" : "bin"}`;
          const savePath = `${project.workspaceDir}/.cph/inbox/${fileName}`;
          await downloadMessageFile(rt, msg.message_id, key, savePath);
          downloadedFiles.push(savePath);
          cleanPrompt = `用户发来一个文件: ${savePath}`;
        }
      } catch { return; }
    }
    if (cleanPrompt === null) return;
    // Slash commands: session management, not agent runs. These bypass the
    // lock — they don't create a run, so they can't conflict with one.
    if (cleanPrompt.startsWith("/")) {
      const cmd = cleanPrompt.split(/\s+/)[0];
      switch (cmd) {
        case "/new": {
          await deps.prisma.agentSession.updateMany({
            where: { projectId, archivedAt: null },
            data: { archivedAt: new Date() },
          });
          await sendText(rt, chatId, "已开新会话,下次 @bot 将从头开始。");
          return;
        }
        case "/resume": {
          const latest = await deps.prisma.agentSession.findFirst({
            where: { projectId, archivedAt: { not: null } },
            orderBy: { archivedAt: "desc" },
            select: { id: true },
          });
          if (latest === null) {
            await sendText(rt, chatId, "没有可恢复的会话。");
            return;
          }
          await deps.prisma.agentSession.update({
            where: { id: latest.id },
            data: { archivedAt: null },
          });
          await sendText(rt, chatId, "已恢复上一个会话。");
          return;
        }
        case "/reset": {
          await deps.prisma.agentSession.updateMany({
            where: { projectId, archivedAt: null },
            data: { archivedAt: new Date() },
          });
          await sendText(rt, chatId, "已重置,下次 @bot 将从头开始。");
          return;
        }
        default:
          break;
      }
    }

    // ADR-0002: if locked by another run, reply busy.
    const existing = await currentLockRunId(deps.prisma, projectId);
    if (existing !== null) {
      await sendText(rt, chatId, "项目正在处理中,请稍候。");
      return;
    }

    const project = await deps.prisma.project.findUnique({
      where: { id: projectId },
      select: { workspaceDir: true },
    });
    if (project === null) {
      deps.logger.error({ projectId }, "feishu trigger: project missing");
      return;
    }

    // ADR-0017: role-as-data. Parse a leading `/<role>` command; unknown
    // slashes are left as literal text (extractRole returns null). Falls back
    // to "draft" when no role is named — the registry degrades gracefully.
    const { roleId: parsedRole } = extractRole(cleanPrompt, deps.models);
    const roleId = parsedRole ?? "draft";
    // Per-role trigger gate (ADR-0017). Orthogonal to ADR-0004's
    // canTriggerAgent above: that checked "can trigger an agent at all";
    // this checks "can trigger *this* role". Unconfigured role ⇒ open.
    if (senderOpenId !== "") {
      const rolePerm = await canTriggerRole(deps.prisma, projectId, roleId, senderOpenId);
      if (!rolePerm.allowed) {
        deps.logger.info({ projectId, roleId, senderOpenId, reason: rolePerm.reason }, "feishu trigger: role permission denied");
        await writeAudit(deps.prisma, { projectId, actorUserId: senderOpenId || undefined, action: "trigger.role_denied", metadata: { roleId, reason: rolePerm.reason } });
        await sendText(rt, chatId, `无权限使用角色 ${roleId}。`);
        return;
      }
    }
    const role = deps.models.role(roleId);
    const model = deps.models.resolve(undefined, roleId);
    const providerId = "openrouter";
    // Per-role bundle (ADR-0017): systemPrompt seeds persona; tools whitelist
    // is enforced inside runAgent when it builds the SDK tools record. `tools:
    // undefined` means the full registered set (unrestricted role).
    const systemPrompt = role?.systemPrompt;

    // ADR-0017: provider+model-bound session. Reuse if one exists for this
    // (project, provider, model) triple; otherwise create.
    const existingSession = await deps.prisma.agentSession.findFirst({
      where: { projectId, provider: providerId, model, archivedAt: null },
      select: { id: true },
    });
    const session =
      existingSession !== null
        ? await deps.prisma.agentSession.update({
            where: { id: existingSession.id },
            data: { provider: providerId, model, updatedAt: new Date() },
            select: { id: true },
          })
        : await deps.prisma.agentSession.create({
            data: {
              projectId,
              provider: providerId,
              model,
              title: cleanPrompt.slice(0, 40) || null,
              metadata: {},
            },
            select: { id: true },
          });

    const run = await deps.prisma.agentRun.create({
      data: {
        projectId,
        sessionId: session.id,
        requestedByUserId: null, // sender→user mapping is OPEN (principal sub-typology)
        entrypoint: "FEISHU",
        status: "ACTIVE",
        prompt: cleanPrompt,
        model,
        provider: providerId,
        metadata: { roleId },
      },
      select: { id: true },
    });
    await writeAudit(deps.prisma, { runId: run.id, projectId, action: "run.created", metadata: { roleId, model, prompt: cleanPrompt.slice(0, 200) } });

    // ADR-0002: acquire the project lock for this run.
    try {
      await acquireLock(deps.prisma, projectId, run.id, null);
    } catch {
      await deps.prisma.agentRun.update({
        where: { id: run.id },
        data: { status: "FAILED", error: "lock race", finishedAt: new Date() },
      });
      await writeAudit(deps.prisma, { runId: run.id, projectId, action: "run.lock_race", metadata: {} });
      await sendText(rt, chatId, "项目正在处理中,请稍候。");
      return;
    }


    const projectCtx: ProjectContext = {
      projectId,
      boundChatId: chatId, // ADR-0003: Feishu reads stay in this chat
      workspaceDir: project.workspaceDir,
    };

    // Emoji reaction on the user's message (acknowledge receipt).
    await reactToMessage(rt, msg.message_id, "THUMBSUP");

    // Stream agent response as text-as-card messages — patchable, markdown,
    // no truncation. Lower throttle (400ms) for smoother streaming.
    let currentMsgId = await sendTextMessage(rt, chatId, "");
    let accText = "";
    let lastPatch = 0;
    const PATCH_INTERVAL = 400;
    const MAX_MSG_LEN = 4000;

    const flushText = async () => {
      const now = Date.now();
      if (now - lastPatch < PATCH_INTERVAL || currentMsgId === null) return;
      lastPatch = now;
      if (accText.length > MAX_MSG_LEN) {
        await patchTextMessage(rt, currentMsgId, accText.slice(0, MAX_MSG_LEN));
        accText = accText.slice(MAX_MSG_LEN);
        currentMsgId = await sendTextMessage(rt, chatId, accText);
      } else {
        await patchTextMessage(rt, currentMsgId, accText);
      }
    };

    runAgent({
      prompt: cleanPrompt,
      model,
      project: projectCtx,
      systemPrompt,
      runId: run.id,
      sessionId: session.id,
      prisma: deps.prisma,
      onStream: (event) => {
        if (event.type === "text-delta") {
          accText += event.text;
          void flushText();
        }
      },
    })
      .then(async (result) => {
        // Final flush: make sure the last message has complete text.
        if (currentMsgId !== null && accText.length > 0) {
          await patchTextMessage(rt, currentMsgId, accText);
        }
        await deps.prisma.agentRun.update({
          where: { id: run.id },
          data: {
            status: result.status === "completed" ? "COMPLETED" : result.status === "length" ? "TIMED_OUT" : "FAILED",
            inputTokens: result.usage.inputTokens,
            outputTokens: result.usage.outputTokens,
            error: result.error ?? null,
            finishedAt: new Date(),
          },
        });
        await writeAudit(deps.prisma, { runId: run.id, projectId, action: "run.finished", metadata: { status: result.status } });

        // Send any new files in build/ as file messages.
        const { readdir, stat } = await import("node:fs/promises");
        const { join } = await import("node:path");
        const buildDir = join(project.workspaceDir, "build");
        try {
          const entries = await readdir(buildDir);
          for (const entry of entries) {
            const fullPath = join(buildDir, entry);
            const s = await stat(fullPath);
            if (s.isFile() && s.mtimeMs > Date.now() - 5 * 60 * 1000) {
              // File created in the last 5 minutes — likely from this run.
              await sendFile(rt, chatId, fullPath, entry);
            }
          }
        } catch { /* no build/ dir — fine */ }
      })
      .catch(async (e) => {
        try {
          await deps.prisma.agentRun.update({
            where: { id: run.id },
            data: { status: "FAILED", error: String(e), finishedAt: new Date() },
          });
        } catch (updateErr) {
          deps.logger.warn({ runId: run.id, err: String(updateErr) }, "trigger: could not mark run FAILED");
        }
        await writeAudit(deps.prisma, { runId: run.id, projectId, action: "run.failed", metadata: { error: String(e) } });
        if (currentMsgId !== null && accText.length === 0) {
          await patchTextMessage(rt, currentMsgId, `⚠️ 处理出错: ${String(e)}`);
        }
      })
      .finally(async () => {
        await releaseLock(deps.prisma, run.id);
      });
  };
}


/**
 * Extract the prompt text from a text message, stripping @mentions.
 * Returns null if the message is empty after stripping or doesn't mention the bot.
 * Lark text content is JSON: `{"text":"@_user_1 do something"}`.
 */
export function extractPrompt(msg: MessageReceiveEvent["message"]): string | null {
  // Check for bot mention — mentions[].id.open_id should include the bot.
  // The dispatcher already routes only message events; we further require
  // that the bot is among the mentions (if no mentions, it's not @bot).
  const mentions = msg.mentions;
  if (mentions === undefined || mentions.length === 0) return null;

  try {
    const parsed = JSON.parse(msg.content) as { text?: string };
    const text = parsed.text;
    if (typeof text !== "string") return null;
    // Strip @mentions (@_user_1 etc.) and trim; remainder is the prompt.
    const stripped = text.replace(/@_\w+\s*/g, "").trim();
    return stripped === "" ? null : stripped;
  } catch {
    return null;
  }
}
/**
 * Parse a leading `/<role>` command from a prompt (e.g. `/draft 帮我写教案`).
 * Returns the role id and the remaining prompt with the command stripped.
 * Control commands already handled upstream (`/new`, `/resume`, `/reset`) are
 * ignored here — they never reach this function.
 *
 * Unknown `/foo` that isn't a registered role: returns `null` role and the
 * original prompt unchanged (the slash is treated as literal text). Role
 * resolution still happens via the registry's fallback.
 */
export function extractRole(
  prompt: string,
  registry: { role(id: string): unknown },
): { roleId: string | null; prompt: string } {
  const m = /^\/(\S+)\s*/.exec(prompt);
  if (m === null || m[1] === undefined) return { roleId: null, prompt };
  const roleId = m[1];
  if (registry.role(roleId) === undefined) {
    // Unknown slash command — leave the prompt as-is (no silent role switch).
    return { roleId: null, prompt };
  }
  return { roleId, prompt: prompt.slice(m[0].length) };
}