/**
 * Agent Router — spawn, stop, delete, list, get, resume, result, questions, output
 */

import { TRPCError } from '@trpc/server';
import { z } from 'zod';
import { tracked, type TrackedEnvelope } from '@trpc/server';
import path from 'path';
import fs from 'fs/promises';
import type { ProcedureBuilder } from '../trpc.js';
import type { TRPCContext } from '../context.js';
import type { AgentInfo, AgentResult, PendingQuestions } from '../../agent/types.js';
import type { AgentOutputEvent } from '../../events/types.js';
import { requireAgentManager, requireLogChunkRepository, requireTaskRepository, requireInitiativeRepository, requireConversationRepository } from './_helpers.js';

export type AgentRadarRow = {
  id: string;
  name: string;
  mode: string;
  status: string;
  initiativeId: string | null;
  initiativeName: string | null;
  taskId: string | null;
  taskName: string | null;
  createdAt: string;
  questionsCount: number;
  messagesCount: number;
  subagentsCount: number;
  compactionsCount: number;
};

export const spawnAgentInputSchema = z.object({
  name: z.string().min(1).optional(),
  taskId: z.string().min(1),
  prompt: z.string().min(1),
  cwd: z.string().optional(),
  mode: z.enum(['execute', 'discuss', 'plan', 'detail', 'refine']).optional(),
  provider: z.string().optional(),
  initiativeId: z.string().min(1).optional(),
});

export type SpawnAgentInput = z.infer<typeof spawnAgentInputSchema>;

export const agentIdentifierSchema = z.object({
  name: z.string().optional(),
  id: z.string().optional(),
}).refine(data => data.name || data.id, {
  message: 'Either name or id must be provided',
});

export type AgentIdentifier = z.infer<typeof agentIdentifierSchema>;

export const resumeAgentInputSchema = z.object({
  name: z.string().optional(),
  id: z.string().optional(),
  answers: z.record(z.string(), z.string()),
}).refine(data => data.name || data.id, {
  message: 'Either name or id must be provided',
});

export type ResumeAgentInput = z.infer<typeof resumeAgentInputSchema>;

async function resolveAgent(
  ctx: TRPCContext,
  input: { name?: string; id?: string }
): Promise<AgentInfo> {
  if (!ctx.agentManager) {
    throw new TRPCError({
      code: 'INTERNAL_SERVER_ERROR',
      message: 'Agent manager not available',
    });
  }

  const agent = input.name
    ? await ctx.agentManager.getByName(input.name)
    : await ctx.agentManager.get(input.id!);

  if (!agent) {
    throw new TRPCError({
      code: 'NOT_FOUND',
      message: `Agent '${input.name ?? input.id}' not found`,
    });
  }

  return agent;
}

export function agentProcedures(publicProcedure: ProcedureBuilder) {
  return {
    spawnAgent: publicProcedure
      .input(spawnAgentInputSchema)
      .mutation(async ({ ctx, input }) => {
        const agentManager = requireAgentManager(ctx);
        return agentManager.spawn({
          name: input.name,
          taskId: input.taskId,
          prompt: input.prompt,
          cwd: input.cwd,
          mode: input.mode,
          provider: input.provider,
          initiativeId: input.initiativeId,
        });
      }),

    stopAgent: publicProcedure
      .input(agentIdentifierSchema)
      .mutation(async ({ ctx, input }) => {
        const agentManager = requireAgentManager(ctx);
        const agent = await resolveAgent(ctx, input);
        await agentManager.stop(agent.id);
        return { success: true, name: agent.name };
      }),

    deleteAgent: publicProcedure
      .input(agentIdentifierSchema)
      .mutation(async ({ ctx, input }) => {
        const agentManager = requireAgentManager(ctx);
        const agent = await resolveAgent(ctx, input);
        await agentManager.delete(agent.id);
        return { success: true, name: agent.name };
      }),

    dismissAgent: publicProcedure
      .input(agentIdentifierSchema)
      .mutation(async ({ ctx, input }) => {
        const agentManager = requireAgentManager(ctx);
        const agent = await resolveAgent(ctx, input);
        await agentManager.dismiss(agent.id);
        return { success: true, name: agent.name };
      }),

    listAgents: publicProcedure
      .query(async ({ ctx }) => {
        const agentManager = requireAgentManager(ctx);
        return agentManager.list();
      }),

    getAgent: publicProcedure
      .input(agentIdentifierSchema)
      .query(async ({ ctx, input }) => {
        const agent = await resolveAgent(ctx, input);

        let taskName: string | null = null;
        let initiativeName: string | null = null;

        if (agent.taskId) {
          const taskRepo = requireTaskRepository(ctx);
          const task = await taskRepo.findById(agent.taskId);
          taskName = task?.name ?? null;
        }
        if (agent.initiativeId) {
          const initiativeRepo = requireInitiativeRepository(ctx);
          const initiative = await initiativeRepo.findById(agent.initiativeId);
          initiativeName = initiative?.name ?? null;
        }

        return { ...agent, taskName, initiativeName };
      }),

    getAgentByName: publicProcedure
      .input(z.object({ name: z.string().min(1) }))
      .query(async ({ ctx, input }) => {
        const agentManager = requireAgentManager(ctx);
        return agentManager.getByName(input.name);
      }),

    resumeAgent: publicProcedure
      .input(resumeAgentInputSchema)
      .mutation(async ({ ctx, input }) => {
        const agentManager = requireAgentManager(ctx);
        const agent = await resolveAgent(ctx, input);
        await agentManager.resume(agent.id, input.answers);
        return { success: true, name: agent.name };
      }),

    getAgentResult: publicProcedure
      .input(agentIdentifierSchema)
      .query(async ({ ctx, input }): Promise<AgentResult | null> => {
        const agentManager = requireAgentManager(ctx);
        const agent = await resolveAgent(ctx, input);
        return agentManager.getResult(agent.id);
      }),

    getAgentQuestions: publicProcedure
      .input(agentIdentifierSchema)
      .query(async ({ ctx, input }): Promise<PendingQuestions | null> => {
        const agentManager = requireAgentManager(ctx);
        const agent = await resolveAgent(ctx, input);
        return agentManager.getPendingQuestions(agent.id);
      }),

    listWaitingAgents: publicProcedure
      .query(async ({ ctx }) => {
        const agentManager = requireAgentManager(ctx);
        const allAgents = await agentManager.list();
        return allAgents.filter(agent => agent.status === 'waiting_for_input');
      }),

    getActiveRefineAgent: publicProcedure
      .input(z.object({ initiativeId: z.string().min(1) }))
      .query(async ({ ctx, input }): Promise<AgentInfo | null> => {
        const agentManager = requireAgentManager(ctx);
        const allAgents = await agentManager.list();
        // Surface discuss and refine agents — both work on initiative content
        const CONTENT_MODES = ['discuss', 'refine'];
        const candidates = allAgents
          .filter(
            (a) =>
              CONTENT_MODES.includes(a.mode) &&
              a.initiativeId === input.initiativeId &&
              ['running', 'waiting_for_input', 'idle', 'crashed'].includes(a.status) &&
              !a.userDismissedAt,
          )
          .sort(
            (a, b) =>
              new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime(),
          );
        return candidates[0] ?? null;
      }),

    getTaskAgent: publicProcedure
      .input(z.object({ taskId: z.string().min(1) }))
      .query(async ({ ctx, input }): Promise<AgentInfo | null> => {
        const agentManager = requireAgentManager(ctx);
        const all = await agentManager.list();
        const matches = all
          .filter(a => a.taskId === input.taskId)
          .sort((a, b) => new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime());
        return matches[0] ?? null;
      }),

    getActiveConflictAgent: publicProcedure
      .input(z.object({ initiativeId: z.string().min(1) }))
      .query(async ({ ctx, input }): Promise<AgentInfo | null> => {
        const agentManager = requireAgentManager(ctx);
        const allAgents = await agentManager.list();
        const candidates = allAgents
          .filter(
            (a) =>
              a.mode === 'execute' &&
              a.initiativeId === input.initiativeId &&
              a.name?.startsWith('conflict-') &&
              ['running', 'waiting_for_input', 'idle', 'crashed'].includes(a.status) &&
              !a.userDismissedAt,
          )
          .sort(
            (a, b) =>
              new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime(),
          );
        return candidates[0] ?? null;
      }),

    getAgentOutput: publicProcedure
      .input(agentIdentifierSchema)
      .query(async ({ ctx, input }) => {
        const agent = await resolveAgent(ctx, input);
        const logChunkRepo = requireLogChunkRepository(ctx);

        const chunks = await logChunkRepo.findByAgentId(agent.id);
        return chunks.map(c => ({
          content: c.content,
          createdAt: c.createdAt.toISOString(),
        }));
      }),

    onAgentOutput: publicProcedure
      .input(z.object({ agentId: z.string().min(1) }))
      .subscription(async function* (opts): AsyncGenerator<TrackedEnvelope<{ agentId: string; data: string }>> {
        const { agentId } = opts.input;
        const signal = opts.signal ?? new AbortController().signal;
        const eventBus = opts.ctx.eventBus;

        let eventCounter = 0;
        const queue: string[] = [];
        let resolve: (() => void) | null = null;

        const handler = (event: AgentOutputEvent) => {
          if (event.payload.agentId !== agentId) return;
          queue.push(event.payload.data);
          if (resolve) {
            const r = resolve;
            resolve = null;
            r();
          }
        };

        eventBus.on('agent:output', handler);

        const cleanup = () => {
          eventBus.off('agent:output', handler);
          if (resolve) {
            const r = resolve;
            resolve = null;
            r();
          }
        };

        signal.addEventListener('abort', cleanup, { once: true });

        try {
          while (!signal.aborted) {
            while (queue.length > 0) {
              const data = queue.shift()!;
              const id = `${agentId}-live-${eventCounter++}`;
              yield tracked(id, { agentId, data });
            }

            if (!signal.aborted) {
              await new Promise<void>((r) => {
                resolve = r;
              });
            }
          }
        } finally {
          cleanup();
        }
      }),

    getAgentInputFiles: publicProcedure
      .input(z.object({ id: z.string().min(1) }))
      .output(z.object({
        files: z.array(z.object({
          name: z.string(),
          content: z.string(),
          sizeBytes: z.number(),
        })),
        reason: z.enum(['worktree_missing', 'input_dir_missing']).optional(),
      }))
      .query(async ({ ctx, input }) => {
        const agent = await resolveAgent(ctx, { id: input.id });

        const worktreeRoot = path.join(ctx.workspaceRoot!, 'agent-workdirs', agent.worktreeId);
        const inputDir = path.join(worktreeRoot, '.cw', 'input');

        // Check worktree root exists
        try {
          await fs.stat(worktreeRoot);
        } catch {
          return { files: [], reason: 'worktree_missing' as const };
        }

        // Check input dir exists
        try {
          await fs.stat(inputDir);
        } catch {
          return { files: [], reason: 'input_dir_missing' as const };
        }

        // Walk inputDir recursively
        const entries = await fs.readdir(inputDir, { recursive: true, withFileTypes: true });
        const MAX_SIZE = 500 * 1024;
        const results: Array<{ name: string; content: string; sizeBytes: number }> = [];

        for (const entry of entries) {
          if (!entry.isFile()) continue;
          // entry.parentPath is available in Node 20+
          const dir = (entry as any).parentPath ?? (entry as any).path;
          const fullPath = path.join(dir, entry.name);
          const relativeName = path.relative(inputDir, fullPath);

          try {
            // Binary detection: read first 512 bytes
            const fd = await fs.open(fullPath, 'r');
            const headerBuf = Buffer.alloc(512);
            const { bytesRead } = await fd.read(headerBuf, 0, 512, 0);
            await fd.close();
            if (headerBuf.slice(0, bytesRead).includes(0)) continue; // skip binary

            const raw = await fs.readFile(fullPath);
            const sizeBytes = raw.length;
            let content: string;
            if (sizeBytes > MAX_SIZE) {
              content = raw.slice(0, MAX_SIZE).toString('utf-8') + '\n\n[truncated — file exceeds 500 KB]';
            } else {
              content = raw.toString('utf-8');
            }
            results.push({ name: relativeName, content, sizeBytes });
          } catch {
            continue; // skip unreadable files
          }
        }

        results.sort((a, b) => a.name.localeCompare(b.name));
        return { files: results };
      }),

    getAgentPrompt: publicProcedure
      .input(z.object({ id: z.string().min(1) }))
      .output(z.object({
        content: z.string().nullable(),
        reason: z.enum(['prompt_not_written']).optional(),
      }))
      .query(async ({ ctx, input }) => {
        const agent = await resolveAgent(ctx, { id: input.id });

        const MAX_BYTES = 1024 * 1024; // 1 MB

        function truncateIfNeeded(text: string): string {
          if (Buffer.byteLength(text, 'utf-8') > MAX_BYTES) {
            const buf = Buffer.from(text, 'utf-8');
            return buf.slice(0, MAX_BYTES).toString('utf-8') + '\n\n[truncated — prompt exceeds 1 MB]';
          }
          return text;
        }

        // Prefer DB-persisted prompt (durable even after log file cleanup)
        if (agent.prompt !== null) {
          return { content: truncateIfNeeded(agent.prompt) };
        }

        // Fall back to filesystem for agents spawned before DB persistence was added
        const promptPath = path.join(ctx.workspaceRoot!, '.cw', 'agent-logs', agent.name, 'PROMPT.md');

        let raw: string;
        try {
          raw = await fs.readFile(promptPath, 'utf-8');
        } catch (err: any) {
          if (err?.code === 'ENOENT') {
            return { content: null, reason: 'prompt_not_written' as const };
          }
          throw new TRPCError({
            code: 'INTERNAL_SERVER_ERROR',
            message: `Failed to read prompt file: ${String(err)}`,
          });
        }

        return { content: truncateIfNeeded(raw) };
      }),

    listForRadar: publicProcedure
      .input(z.object({
        timeRange: z.enum(['1h', '6h', '24h', '7d', 'all']).default('24h'),
        status: z.enum(['running', 'completed', 'crashed']).optional(),
        initiativeId: z.string().optional(),
        mode: z.enum(['execute', 'discuss', 'plan', 'detail', 'refine', 'chat', 'errand']).optional(),
      }))
      .query(async ({ ctx, input }): Promise<AgentRadarRow[]> => {
        const agentManager = requireAgentManager(ctx);
        const allAgents = await agentManager.list();

        // Compute cutoff
        const cutoffMap: Record<string, number> = {
          '1h': Date.now() - 3_600_000,
          '6h': Date.now() - 21_600_000,
          '24h': Date.now() - 86_400_000,
          '7d': Date.now() - 604_800_000,
        };
        const cutoff = input.timeRange !== 'all' ? cutoffMap[input.timeRange] : null;

        // Filter agents
        let filteredAgents = allAgents;
        if (cutoff !== null) {
          filteredAgents = filteredAgents.filter(a => a.createdAt.getTime() >= cutoff!);
        }
        if (input.status !== undefined) {
          const dbStatus = input.status === 'completed' ? 'stopped' : input.status;
          filteredAgents = filteredAgents.filter(a => a.status === dbStatus);
        }
        if (input.initiativeId !== undefined) {
          filteredAgents = filteredAgents.filter(a => a.initiativeId === input.initiativeId);
        }
        if (input.mode !== undefined) {
          filteredAgents = filteredAgents.filter(a => a.mode === input.mode);
        }

        const matchingIds = filteredAgents.map(a => a.id);

        // Batch fetch in parallel
        const logChunkRepo = requireLogChunkRepository(ctx);
        const conversationRepo = requireConversationRepository(ctx);
        const initiativeRepo = requireInitiativeRepository(ctx);
        const taskRepo = requireTaskRepository(ctx);

        // Collect unique taskIds and initiativeIds for batch lookup
        const uniqueTaskIds = [...new Set(filteredAgents.map(a => a.taskId).filter(Boolean) as string[])];
        const uniqueInitiativeIds = [...new Set(filteredAgents.map(a => a.initiativeId).filter(Boolean) as string[])];

        const [metrics, messageCounts, taskResults, initiativeResults] = await Promise.all([
          logChunkRepo.findMetricsByAgentIds(matchingIds),
          conversationRepo.countByFromAgentIds(matchingIds),
          Promise.all(uniqueTaskIds.map(id => taskRepo.findById(id))),
          Promise.all(uniqueInitiativeIds.map(id => initiativeRepo.findById(id))),
        ]);

        // Build lookup maps
        const taskMap = new Map(taskResults.filter(Boolean).map(t => [t!.id, t!.name]));
        const initiativeMap = new Map(initiativeResults.filter(Boolean).map(i => [i!.id, i!.name]));
        const messagesMap = new Map(messageCounts.map(m => [m.agentId, m.count]));
        const metricsMap = new Map(metrics.map(m => [m.agentId, m]));

        // Build result rows
        return filteredAgents.map(agent => {
          const agentMetrics = metricsMap.get(agent.id);
          const questionsCount = agentMetrics?.questionsCount ?? 0;
          const subagentsCount = agentMetrics?.subagentsCount ?? 0;
          const compactionsCount = agentMetrics?.compactionsCount ?? 0;

          return {
            id: agent.id,
            name: agent.name,
            mode: agent.mode,
            status: agent.status,
            initiativeId: agent.initiativeId,
            initiativeName: agent.initiativeId ? (initiativeMap.get(agent.initiativeId) ?? null) : null,
            taskId: agent.taskId,
            taskName: agent.taskId ? (taskMap.get(agent.taskId) ?? null) : null,
            createdAt: agent.createdAt.toISOString(),
            questionsCount,
            messagesCount: messagesMap.get(agent.id) ?? 0,
            subagentsCount,
            compactionsCount,
          };
        });
      }),

    getCompactionEvents: publicProcedure
      .input(z.object({ agentId: z.string().min(1) }))
      .query(async ({ ctx, input }) => {
        const logChunkRepo = requireLogChunkRepository(ctx);
        const chunks = await logChunkRepo.findByAgentId(input.agentId);
        const results: { timestamp: string; sessionNumber: number }[] = [];
        for (const chunk of chunks) {
          try {
            const parsed = JSON.parse(chunk.content);
            if (parsed.type === 'system' && parsed.subtype === 'init' && parsed.source === 'compact') {
              results.push({ timestamp: chunk.createdAt.toISOString(), sessionNumber: chunk.sessionNumber });
            }
          } catch { /* skip malformed */ }
          if (results.length >= 200) break;
        }
        return results;
      }),

    getSubagentSpawns: publicProcedure
      .input(z.object({ agentId: z.string().min(1) }))
      .query(async ({ ctx, input }) => {
        const logChunkRepo = requireLogChunkRepository(ctx);
        const chunks = await logChunkRepo.findByAgentId(input.agentId);
        const results: { timestamp: string; description: string; promptPreview: string; fullPrompt: string }[] = [];
        for (const chunk of chunks) {
          try {
            const parsed = JSON.parse(chunk.content);
            if (parsed.type === 'tool_use' && parsed.name === 'Agent') {
              const fullPrompt: string = parsed.input?.prompt ?? '';
              const description: string = parsed.input?.description ?? '';
              results.push({
                timestamp: chunk.createdAt.toISOString(),
                description,
                promptPreview: fullPrompt.slice(0, 200),
                fullPrompt,
              });
            }
          } catch { /* skip malformed */ }
          if (results.length >= 200) break;
        }
        return results;
      }),

    getQuestionsAsked: publicProcedure
      .input(z.object({ agentId: z.string().min(1) }))
      .query(async ({ ctx, input }) => {
        const logChunkRepo = requireLogChunkRepository(ctx);
        const chunks = await logChunkRepo.findByAgentId(input.agentId);
        type QuestionItem = { question: string; header: string; options: { label: string; description: string }[] };
        const results: { timestamp: string; questions: QuestionItem[] }[] = [];
        for (const chunk of chunks) {
          try {
            const parsed = JSON.parse(chunk.content);
            if (parsed.type === 'tool_use' && parsed.name === 'AskUserQuestion') {
              const questions: QuestionItem[] = parsed.input?.questions ?? [];
              results.push({ timestamp: chunk.createdAt.toISOString(), questions });
            }
          } catch { /* skip malformed */ }
          if (results.length >= 200) break;
        }
        return results;
      }),
  };
}