/**
 * Runner for built-in diagnostic skills.
 *
 * Fetches the skill by id, filters its steps for the target session's shell
 * family, executes each step sequentially via the bridge, and assembles a
 * single structured report with labels, stdout/stderr, and exit codes.
 */

import { getBuiltinSkill, filterStepsForShell, type SkillStep } from './builtinSkills';
import type { ToolDeps, ToolExecResult } from '../shared/toolExecutors';

interface RunOptions {
  chatSessionId?: string;
}

interface StepResult {
  label: string;
  command: string;
  stdout: string;
  stderr: string;
  exitCode: number | null;
  durationMs: number;
  ok: boolean;
}

export interface SkillRunReport {
  skill: string;
  sessionId: string;
  shellType?: string;
  os?: string;
  hostname?: string;
  startedAt: string;
  completedAt: string;
  durationMs: number;
  steps: StepResult[];
}

export async function executeSkillRun(
  deps: ToolDeps,
  args: Record<string, unknown>,
  options: RunOptions = {},
): Promise<ToolExecResult<SkillRunReport>> {
  const { bridge, context, permissionMode } = deps;
  const resolveContext = () => (typeof context === 'function' ? context() : context);
  const ctx = resolveContext();

  const sessionId = typeof args.sessionId === 'string' ? args.sessionId.trim() : '';
  const skillName = typeof args.skillName === 'string' ? args.skillName.trim() : '';

  if (!sessionId) {
    return { ok: false, error: 'Missing sessionId.' };
  }
  if (!skillName) {
    return { ok: false, error: 'Missing skillName.' };
  }

  if (permissionMode === 'observer') {
    return { ok: false, error: 'Observer mode: skill execution is disabled. Switch to Confirm or Auto mode.' };
  }

  // Validate session is in scope
  const session = ctx.sessions.find(s => s.sessionId === sessionId);
  if (!session) {
    return { ok: false, error: `Session "${sessionId}" is not in the current AI scope.` };
  }

  // Resolve skill
  const skill = getBuiltinSkill(skillName);
  if (!skill) {
    const available = Object.keys((await import('./builtinSkills')).BUILTIN_SKILLS).join(', ');
    return { ok: false, error: `Unknown skill "${skillName}". Available: ${available}` };
  }

  // Filter steps for this shell family
  const steps = filterStepsForShell(skill, session.shellType);
  if (steps.length === 0) {
    return {
      ok: false,
      error: `Skill "${skill.id}" has no steps for shell family "${session.shellType ?? 'unknown'}".`,
    };
  }

  // Run each step sequentially, capture everything
  const startedAt = new Date();
  const stepResults: StepResult[] = [];

  for (const step of steps) {
    const stepResult = await runStep(bridge, sessionId, step, options.chatSessionId);
    stepResults.push(stepResult);
  }

  const completedAt = new Date();
  const report: SkillRunReport = {
    skill: skill.id,
    sessionId,
    shellType: session.shellType,
    os: session.os,
    hostname: session.hostname,
    startedAt: startedAt.toISOString(),
    completedAt: completedAt.toISOString(),
    durationMs: completedAt.getTime() - startedAt.getTime(),
    steps: stepResults,
  };

  return { ok: true, data: report };
}

async function runStep(
  bridge: NonNullable<ToolDeps['bridge']>,
  sessionId: string,
  step: SkillStep,
  chatSessionId?: string,
): Promise<StepResult> {
  const t0 = Date.now();
  try {
    const result = await bridge.aiExec(sessionId, step.command, chatSessionId);
    const durationMs = Date.now() - t0;

    if (!result.ok && result.error) {
      return {
        label: step.label,
        command: step.command,
        stdout: result.stdout || '',
        stderr: `[exec error] ${result.error}`,
        exitCode: null,
        durationMs,
        ok: false,
      };
    }

    return {
      label: step.label,
      command: step.command,
      stdout: result.stdout || '',
      stderr: result.stderr || '',
      exitCode: result.exitCode ?? -1,
      durationMs,
      ok: (result.exitCode ?? 0) === 0,
    };
  } catch (err) {
    const durationMs = Date.now() - t0;
    return {
      label: step.label,
      command: step.command,
      stdout: '',
      stderr: `[exception] ${err instanceof Error ? err.message : String(err)}`,
      exitCode: null,
      durationMs,
      ok: false,
    };
  }
}