/**
 * Post-planning kickoff: plan is ready — implement (no full draft paste).
 */

import type { PlannerMode, PlannerReason } from "./run-planner.ts";

export function buildExecuteKickoffPrompt(input: {
  objective: string;
  planPath: string;
  evidencePath: string;
  plannerMode: PlannerMode;
  /** Why planning used this mode (B026 — never claim "unavailable" on timeout). */
  plannerReason?: PlannerReason;
}): string {
  const modeNote = describePlannerKickoffMode(input.plannerMode, input.plannerReason);

  return [
    "# Goal — execute",
    "",
    `**Objective:** ${input.objective}`,
    `**Plan (source of truth):** \`${input.planPath}\``,
    `**Evidence index:** \`${input.evidencePath}\``,
    "",
    modeNote,
    "",
    "## Do this now",
    `1. Read \`${input.planPath}\` fully.`,
    "2. If the plan is still a weak skeleton, expand it in place (outcome-based criteria, verification plan, task checklist) using codebase research — then continue.",
    "3. Implement against the plan. Flip task-checklist `- [ ]` → `- [x]` as you go.",
    `4. Maintain \`${input.evidencePath}\` (criterion → artifact paths).`,
    "5. **Required progress milestones** — call `update_goal({ message })` at least for: `researched`, `implementing`, `pre-complete` (optional mid-checklist notes too). Use `update_goal({ completed: true })` only when verification observations hold.",
    "6. `update_goal({ blocked_reason })` only after genuine stuckness.",
    "",
    "Goal state lives under `.pi/goal/` (session cwd / `PI_GOAL_ROOT` / `PI_GOAL_CWD`);",
    "the objective may require edits **outside** that directory — edit scope follows the objective, not the goal store.",
    "Read and rewrite the plan file on disk; do not paste the full draft back into the transcript.",
    "No test theater. Do not wait for the user to restate the goal.",
  ].join("\n");
}

/** Human-readable kickoff note; timeout never reaches kickoff (fail-CLOSED). */
export function describePlannerKickoffMode(
  mode: PlannerMode,
  reason?: PlannerReason,
): string {
  if (mode === "subagent") {
    return "A planner subagent researched the codebase and wrote the plan file.";
  }

  switch (reason) {
    case "ping_failed":
      return "A structural draft plan was written (pi-subagents ping failed). Review and tighten the plan before heavy implementation if needed.";
    case "no_bus":
      return "A structural draft plan was written (no event bus / pi.events). Review and tighten the plan before heavy implementation if needed.";
    case "agent_failed":
      return "A structural draft plan was written (planner subagent failed). Review and tighten the plan before heavy implementation if needed.";
    case "spawn_error":
      return "A structural draft plan was written (planner spawn error). Review and tighten the plan before heavy implementation if needed.";
    case "wait_timeout":
      // Should not appear on execute kickoff (planning fails closed); keep honest copy.
      return "Planning timed out waiting for the planner subagent. Resume after /goal resume only if a usable plan exists on disk; do not treat a skeleton as final criteria.";
    case "structural_fallback":
    case "ok":
    default:
      return "A structural draft plan was written (pi-subagents unavailable). Review and tighten the plan before heavy implementation if needed.";
  }
}