/**
 * Prompt Builder for Stateless Generation
 *
 * Builds system prompts and converts messages for the LLM.
 */

import type { StatelessChatRequest } from '@/lib/types/chat';
import type { AgentConfig } from '@/lib/orchestration/registry/types';
import type { WhiteboardActionRecord, AgentTurnSummary } from './types';
import { getActionDescriptions, getEffectiveActions } from './tool-schemas';
import { buildStateContext } from './summarizers/state-context';
import { buildVirtualWhiteboardContext } from './summarizers/whiteboard-ledger';
import { buildPeerContextSection } from './summarizers/peer-context';
import { buildPrompt, PROMPT_IDS } from '@/lib/prompts';

// ==================== Role Guidelines ====================

const ROLE_GUIDELINES: Record<string, string> = {
  teacher: `Your role in this classroom: LEAD TEACHER.
You are responsible for:
- Controlling the lesson flow, slides, and pacing
- Explaining concepts clearly with examples and analogies
- Asking questions to check understanding
- Using spotlight/laser to direct attention to slide elements
- Using the whiteboard for diagrams and formulas
You can use all available actions. Never announce your actions — just teach naturally.`,

  assistant: `Your role in this classroom: TEACHING ASSISTANT.
You are responsible for:
- Supporting the lead teacher by filling gaps and answering side questions
- Rephrasing explanations in simpler terms when students are confused
- Providing concrete examples and background context
- Using the whiteboard sparingly to supplement (not duplicate) the teacher's content
You play a supporting role — don't take over the lesson.`,

  student: `Your role in this classroom: STUDENT.
You are responsible for:
- Participating actively in discussions
- Asking questions, sharing observations, reacting to the lesson
- Keeping responses SHORT (1-2 sentences max)
- Only using the whiteboard when explicitly invited by the teacher
You are NOT a teacher — your responses should be much shorter than the teacher's.`,
};

// ==================== Types ====================

/**
 * Discussion context for agent-initiated discussions
 */
interface DiscussionContext {
  topic: string;
  prompt?: string;
}

// ==================== Per-variant string constants ====================

const FORMAT_EXAMPLE_SLIDE = `[{"type":"action","name":"spotlight","params":{"elementId":"img_1"}},{"type":"text","content":"Your natural speech to students"}]`;
const FORMAT_EXAMPLE_WB = `[{"type":"action","name":"wb_open","params":{}},{"type":"text","content":"Your natural speech to students"}]`;

const ORDERING_SLIDE = `- spotlight/laser actions should appear BEFORE the corresponding text object (point first, then speak)
- whiteboard actions can interleave WITH text objects (draw while speaking)`;
const ORDERING_WB = `- whiteboard actions can interleave WITH text objects (draw while speaking)`;

const SPOTLIGHT_EXAMPLES = `[{"type":"action","name":"spotlight","params":{"elementId":"img_1"}},{"type":"text","content":"Photosynthesis is the process by which plants convert light energy into chemical energy. Take a look at this diagram."},{"type":"text","content":"During this process, plants absorb carbon dioxide and water to produce glucose and oxygen."}]

[{"type":"action","name":"spotlight","params":{"elementId":"eq_1"}},{"type":"action","name":"laser","params":{"elementId":"eq_2"}},{"type":"text","content":"Compare these two equations — notice how the left side is endothermic while the right side is exothermic."}]

`;

const SLIDE_ACTION_GUIDELINES = `- spotlight: Use to focus attention on ONE key element. Don't overuse — max 1-2 per response.
- laser: Use to point at elements. Good for directing attention during explanations.
`;

const MUTUAL_EXCLUSION_NOTE = `- IMPORTANT — Whiteboard / Canvas mutual exclusion: The whiteboard and slide canvas are mutually exclusive. When the whiteboard is OPEN, the slide canvas is hidden — spotlight and laser actions targeting slide elements will have NO visible effect. If you need to use spotlight or laser, call wb_close first to reveal the slide canvas. Conversely, if the whiteboard is CLOSED, wb_draw_* actions still work (they implicitly open the whiteboard), but be aware that doing so hides the slide canvas.
- Prefer variety: mix spotlights, laser, and whiteboard for engaging teaching. Don't use the same action type repeatedly.`;

// ==================== Private helpers ====================

function buildStudentProfileSection(userProfile?: { nickname?: string; bio?: string }): string {
  if (!userProfile?.nickname && !userProfile?.bio) return '';
  return `\n# Student Profile
You are teaching ${userProfile.nickname || 'a student'}.${userProfile.bio ? `\nTheir background: ${userProfile.bio}` : ''}
Personalize your teaching based on their background when relevant. Address them by name naturally.\n`;
}

function buildLanguageConstraint(langDirective?: string): string {
  return langDirective ? `\n# Language (CRITICAL)\n${langDirective}\n` : '';
}

function buildDiscussionContextSection(
  discussionContext: DiscussionContext | undefined,
  agentResponses: AgentTurnSummary[] | undefined,
): string {
  if (!discussionContext) return '';
  if (agentResponses && agentResponses.length > 0) {
    return `

# Discussion Context
Topic: "${discussionContext.topic}"
${discussionContext.prompt ? `Guiding prompt: ${discussionContext.prompt}` : ''}

You are JOINING an ongoing discussion — do NOT re-introduce the topic or greet the students. The discussion has already started. Contribute your unique perspective, ask a follow-up question, or challenge an assumption made by a previous speaker.`;
  }
  return `

# Discussion Context
You are initiating a discussion on the following topic: "${discussionContext.topic}"
${discussionContext.prompt ? `Guiding prompt: ${discussionContext.prompt}` : ''}

IMPORTANT: As you are starting this discussion, begin by introducing the topic naturally to the students. Engage them and invite their thoughts. Do not wait for user input - you speak first.`;
}

// ==================== System Prompt ====================

/**
 * Build system prompt for structured output generation
 *
 * @param agentConfig - The agent configuration
 * @param storeState - Current application state
 * @param discussionContext - Optional discussion context for agent-initiated discussions
 * @returns System prompt string
 */
export function buildStructuredPrompt(
  agentConfig: AgentConfig,
  storeState: StatelessChatRequest['storeState'],
  discussionContext?: DiscussionContext,
  whiteboardLedger?: WhiteboardActionRecord[],
  userProfile?: { nickname?: string; bio?: string },
  agentResponses?: AgentTurnSummary[],
): string {
  // Determine current scene type for action filtering
  const currentScene = storeState.currentSceneId
    ? storeState.scenes.find((s) => s.id === storeState.currentSceneId)
    : undefined;
  const sceneType = currentScene?.type;
  const effectiveActions = getEffectiveActions(agentConfig.allowedActions, sceneType);
  const hasSlideActions =
    effectiveActions.includes('spotlight') || effectiveActions.includes('laser');

  const vars = {
    agentName: agentConfig.name,
    persona: agentConfig.persona,
    roleGuideline: ROLE_GUIDELINES[agentConfig.role] || ROLE_GUIDELINES.student,
    studentProfileSection: buildStudentProfileSection(userProfile),
    peerContext: buildPeerContextSection(agentResponses, agentConfig.name),
    languageConstraint: buildLanguageConstraint(storeState.stage?.languageDirective),
    formatExample: hasSlideActions ? FORMAT_EXAMPLE_SLIDE : FORMAT_EXAMPLE_WB,
    orderingPrinciples: hasSlideActions ? ORDERING_SLIDE : ORDERING_WB,
    spotlightExamples: hasSlideActions ? SPOTLIGHT_EXAMPLES : '',
    actionDescriptions: getActionDescriptions(effectiveActions),
    slideActionGuidelines: hasSlideActions ? SLIDE_ACTION_GUIDELINES : '',
    mutualExclusionNote: hasSlideActions ? MUTUAL_EXCLUSION_NOTE : '',
    stateContext: buildStateContext(storeState),
    virtualWhiteboardContext: buildVirtualWhiteboardContext(storeState, whiteboardLedger),
    lengthGuidelines: buildLengthGuidelines(agentConfig.role),
    whiteboardGuidelines: buildWhiteboardGuidelines(agentConfig.role),
    discussionContextSection: buildDiscussionContextSection(discussionContext, agentResponses),
  };

  const prompt = buildPrompt(PROMPT_IDS.AGENT_SYSTEM, vars);
  if (!prompt) {
    throw new Error('agent-system template not found');
  }
  return prompt.system;
}

// ==================== Length Guidelines ====================

/**
 * Build role-aware length and style guidelines.
 *
 * All agents should be concise and conversational. Student agents must be
 * significantly shorter than teacher to avoid overshadowing the teacher's role.
 */
function buildLengthGuidelines(role: string): string {
  const common = `- Length targets count ONLY your speech text (type:"text" content). Actions (spotlight, whiteboard, etc.) do NOT count toward length. Use as many actions as needed — they don't make your speech "too long."
- Speak conversationally and naturally — this is a live classroom, not a textbook. Use oral language, not written prose.`;

  if (role === 'teacher') {
    return `- Keep your TOTAL speech text around 100 characters (across all text objects combined). Prefer 2-3 short sentences over one long paragraph.
${common}
- Prioritize inspiring students to THINK over explaining everything yourself. Ask questions, pose challenges, give hints — don't just lecture.
- When explaining, give the key insight in one crisp sentence, then pause or ask a question. Avoid exhaustive explanations.`;
  }

  if (role === 'assistant') {
    return `- Keep your TOTAL speech text around 80 characters. You are a supporting role — be brief.
${common}
- One key point per response. Don't repeat the teacher's full explanation — add a quick angle, example, or summary.`;
  }

  // Student roles — must be noticeably shorter than teacher
  return `- Keep your TOTAL speech text around 50 characters. 1-2 sentences max.
${common}
- You are a STUDENT, not a teacher. Your responses should be much shorter than the teacher's. If your response is as long as the teacher's, you are doing it wrong.
- Speak in quick, natural reactions: a question, a joke, a brief insight, a short observation. Not paragraphs.
- Inspire and provoke thought with punchy comments, not lengthy analysis.`;
}

// ==================== Whiteboard Guidelines ====================

/**
 * Build role-aware whiteboard guidelines.
 *
 * Content lives in markdown templates under lib/prompts/templates/agent-system-wb-<role>/
 * with the shared reference at lib/prompts/snippets/whiteboard-reference.md.
 */
function buildWhiteboardGuidelines(role: string): string {
  const templateId =
    role === 'teacher'
      ? PROMPT_IDS.AGENT_SYSTEM_WB_TEACHER
      : role === 'assistant'
        ? PROMPT_IDS.AGENT_SYSTEM_WB_ASSISTANT
        : PROMPT_IDS.AGENT_SYSTEM_WB_STUDENT;

  const prompt = buildPrompt(templateId, {});
  if (!prompt) {
    throw new Error(`${templateId} template not found`);
  }
  return prompt.system;
}