/**
 * Drizzle Log Chunk Repository Adapter
 *
 * Implements LogChunkRepository interface using Drizzle ORM.
 */

import { eq, asc, max, inArray, sql } from 'drizzle-orm';
import { nanoid } from 'nanoid';
import type { DrizzleDatabase } from '../../index.js';
import { agentLogChunks, agentMetrics } from '../../schema.js';
import type { LogChunkRepository } from '../log-chunk-repository.js';

export class DrizzleLogChunkRepository implements LogChunkRepository {
  constructor(private db: DrizzleDatabase) {}

  async insertChunk(data: {
    agentId: string;
    agentName: string;
    sessionNumber: number;
    content: string;
  }): Promise<void> {
    // better-sqlite3 is synchronous — transaction callback must be sync, use .run() not await
    this.db.transaction((tx) => {
      // 1. Always insert the chunk row first
      tx.insert(agentLogChunks).values({
        id: nanoid(),
        agentId: data.agentId,
        agentName: data.agentName,
        sessionNumber: data.sessionNumber,
        content: data.content,
        createdAt: new Date(),
      }).run();

      // 2. Parse content and determine metric increments
      //    Wrap only the parse + upsert block — chunk insert is not rolled back on parse failure
      try {
        const parsed = JSON.parse(data.content);
        let deltaQuestions = 0;
        let deltaSubagents = 0;
        let deltaCompactions = 0;

        if (parsed.type === 'tool_use' && parsed.name === 'AskUserQuestion') {
          deltaQuestions = parsed.input?.questions?.length ?? 0;
        } else if (parsed.type === 'tool_use' && parsed.name === 'Agent') {
          deltaSubagents = 1;
        } else if (parsed.type === 'system' && parsed.subtype === 'init' && parsed.source === 'compact') {
          deltaCompactions = 1;
        }

        // 3. Only upsert if there is something to increment
        if (deltaQuestions > 0 || deltaSubagents > 0 || deltaCompactions > 0) {
          tx.insert(agentMetrics)
            .values({
              agentId: data.agentId,
              questionsCount: deltaQuestions,
              subagentsCount: deltaSubagents,
              compactionsCount: deltaCompactions,
              updatedAt: new Date(),
            })
            .onConflictDoUpdate({
              target: agentMetrics.agentId,
              set: {
                questionsCount: sql`${agentMetrics.questionsCount} + ${deltaQuestions}`,
                subagentsCount: sql`${agentMetrics.subagentsCount} + ${deltaSubagents}`,
                compactionsCount: sql`${agentMetrics.compactionsCount} + ${deltaCompactions}`,
                updatedAt: new Date(),
              },
            })
            .run();
        }
      } catch {
        // Malformed JSON — skip metric upsert, chunk insert already committed within transaction
      }
    });
  }

  async findByAgentId(agentId: string): Promise<{ content: string; sessionNumber: number; createdAt: Date }[]> {
    return this.db
      .select({
        content: agentLogChunks.content,
        sessionNumber: agentLogChunks.sessionNumber,
        createdAt: agentLogChunks.createdAt,
      })
      .from(agentLogChunks)
      .where(eq(agentLogChunks.agentId, agentId))
      .orderBy(asc(agentLogChunks.createdAt));
  }

  async findByAgentIds(agentIds: string[]): Promise<{ agentId: string; content: string; sessionNumber: number; createdAt: Date }[]> {
    if (agentIds.length === 0) return [];
    return this.db
      .select({
        agentId: agentLogChunks.agentId,
        content: agentLogChunks.content,
        sessionNumber: agentLogChunks.sessionNumber,
        createdAt: agentLogChunks.createdAt,
      })
      .from(agentLogChunks)
      .where(inArray(agentLogChunks.agentId, agentIds))
      .orderBy(asc(agentLogChunks.createdAt));
  }

  async deleteByAgentId(agentId: string): Promise<void> {
    await this.db
      .delete(agentLogChunks)
      .where(eq(agentLogChunks.agentId, agentId));
  }

  async getSessionCount(agentId: string): Promise<number> {
    const result = await this.db
      .select({ maxSession: max(agentLogChunks.sessionNumber) })
      .from(agentLogChunks)
      .where(eq(agentLogChunks.agentId, agentId));

    return result[0]?.maxSession ?? 0;
  }

  async findMetricsByAgentIds(agentIds: string[]): Promise<{
    agentId: string;
    questionsCount: number;
    subagentsCount: number;
    compactionsCount: number;
  }[]> {
    if (agentIds.length === 0) return [];
    return this.db
      .select({
        agentId: agentMetrics.agentId,
        questionsCount: agentMetrics.questionsCount,
        subagentsCount: agentMetrics.subagentsCount,
        compactionsCount: agentMetrics.compactionsCount,
      })
      .from(agentMetrics)
      .where(inArray(agentMetrics.agentId, agentIds));
  }
}