/*!
 * SPDX-License-Identifier: AGPL-3.0-or-later
 * Copyright © 2026 Diego Lima Nogueira de Paula
 *
 * /graph-plan — PLAN phase: decompose epics, plan sprint, estimate.
 * No MCP dependency. Operates directly against SqliteStore.
 */

import type { SkillHandlerPort, SkillExecutionContext } from "../../tui/skill-handler-port.js";
import { fmtElapsed } from "../shared/handler-utils.js";
import { createLogger } from "../../core/utils/logger.js";

const _log = createLogger({ layer: "core", source: "graph-plan.ts" });

export class GraphPlanHandler implements SkillHandlerPort {
  async execute(args: string, ctx: SkillExecutionContext): Promise<string> {
    const { store, onProgress } = ctx;
    const startMs = Date.now();
    const lines: string[] = ["═ /graph-plan ═"];
    const doc = store.toGraphDocument();

    // Step 1: Find epics without tasks
    onProgress({ step: 1, total: 5, label: "Analisando epics...", elapsedMs: Date.now() - startMs, tokensUsed: 0 });
    const epics = doc.nodes.filter((n) => n.type === "epic" && n.status !== "done");
    const undecomposed = epics.filter((e) => !doc.nodes.some((n) => n.parentId === e.id));
    lines.push(`Epics: ${epics.length} · Sem tasks: ${undecomposed.length}`);

    for (const e of undecomposed.slice(0, 5)) {
      lines.push(`  ⚠ ${e.title} (${e.id}) — sem tasks filhas`);
    }

    // Step 2: Check for oversized tasks
    onProgress({ step: 2, total: 5, label: "Verificando sizing...", elapsedMs: Date.now() - startMs, tokensUsed: 0 });
    const tasks = doc.nodes.filter((n) => n.type === "task" || n.type === "subtask");
    const oversized = tasks.filter(
      (t) => (t.xpSize === "L" || t.xpSize === "XL") && !doc.nodes.some((n) => n.parentId === t.id),
    );
    lines.push(`Tasks: ${tasks.length} · Oversized (L/XL sem subtasks): ${oversized.length}`);

    // Step 3: Dependency check
    onProgress({ step: 3, total: 5, label: "Mapeando dependências...", elapsedMs: Date.now() - startMs, tokensUsed: 0 });
    const deps = doc.edges.filter((e) => e.relationType === "depends_on");
    const tasksWithDeps = new Set(deps.map((d) => d.from));
    lines.push(`Dependências: ${deps.length} aresta(s) · ${tasksWithDeps.size} task(s) com dependências`);

    // Step 4: Sprint planning
    onProgress({ step: 4, total: 5, label: "Planejando sprint...", elapsedMs: Date.now() - startMs, tokensUsed: 0 });
    const sprints = new Set(tasks.map((t) => t.sprint).filter(Boolean));
    const unassigned = tasks.filter((t) => !t.sprint && (t.status === "backlog" || t.status === "ready"));
    lines.push(`Sprints: ${sprints.size > 0 ? [...sprints].join(", ") : "nenhum"} · Não atribuídas: ${unassigned.length}`);

    // Estimate totals
    const estimated = tasks.filter((t) => t.estimateMinutes != null);
    const totalEstimate = estimated.reduce((acc, t) => acc + (t.estimateMinutes ?? 0), 0);
    lines.push(`Estimativa total: ${totalEstimate}min (${estimated.length}/${tasks.length} tasks estimadas)`);

    // Step 5: Recommendations
    onProgress({ step: 5, total: 5, label: "Recomendações...", elapsedMs: Date.now() - startMs, tokensUsed: 0 });
    if (undecomposed.length > 0) {
      lines.push("Recomendação: decomponha epics sem tasks com smart_decompose.");
    }
    if (oversized.length > 0) {
      lines.push("Recomendação: decomponha tasks L/XL em subtasks menores.");
    }
    if (unassigned.length > 0) {
      lines.push("Recomendação: atribua sprints às tasks não planejadas.");
    }

    lines.push(`═ ${fmtElapsed(Date.now() - startMs)} ═`);
    return lines.join("\n");
  }
}