import { z } from 'zod';
import type { LlmClient } from '@/lib/ai/llm-client';
import { GeminiLlmClient } from '@/lib/ai/gemini-client';
import { clamp, nowIso, loadPhaseContainers, persistPhaseArtifacts } from '@/lib/server/projects';
import type { MvpPlan } from '@/lib/types/mvp';

const MvpPlanSchema = z.object({
  projectId: z.string(),
  coreFlows: z.array(z.string()).default([]),
  coreFeatures: z.array(z.string()).default([]),
  supportingFeatures: z.array(z.string()).default([]),
  outOfScope: z.array(z.string()).default([]),
  technicalTasks: z.array(z.string()).default([]),
  blockers: z.array(z.string()).default([]),
  overallConfidence: z.number().min(0).max(1),
});

export async function runMvpPlanning(projectId: string, llmClient?: LlmClient): Promise<MvpPlan> {
  const { phaseData } = await loadPhaseContainers(projectId);
  const canonical = phaseData.canonicalProductModel;
  if (!canonical) {
    throw new Error('Canonical product model missing. Run buildCanonicalProductModel first.');
  }

  const llm = llmClient ?? new GeminiLlmClient();
  const systemPrompt =
    'You are an expert SaaS product manager. Given the canonical product model, produce the smallest sellable MVP plan as strict JSON.';

  const plan = await llm.structuredCall<MvpPlan>({
    model: 'gemini',
    systemPrompt,
    messages: [
      {
        role: 'user',
        content: [
          'Canonical product model JSON:',
          '```json',
          JSON.stringify(canonical, null, 2),
          '```',
          'Respond ONLY with JSON that matches the required schema.',
        ].join('\n'),
      },
    ],
    schema: MvpPlanSchema,
    temperature: 0.2,
  });

  await persistPhaseArtifacts(projectId, (phaseData, phaseScores, phaseHistory) => {
    phaseData.mvpPlan = plan;
    phaseScores.mvp = {
      overallCompletion: clamp(plan.coreFeatures.length ? 0.8 : 0.5),
      overallConfidence: plan.overallConfidence,
      updatedAt: nowIso(),
    };
    phaseHistory.push({ phase: 'mvp', status: 'completed', timestamp: nowIso() });
    return { phaseData, phaseScores, phaseHistory, nextPhase: 'mvp_ready' };
  });

  return plan;
}