import { Router, Request, Response } from 'express';
import {
  getSession,
  getTeams,
  getJurors,
  getScores,
  addScore,
  updateSession,
  getStore,
} from './store.js';
import { resolveConflict } from './conflict.js';
import { calculateAllResults, getCompletionStatus } from './aggregation.js';
import { broadcastUpdate } from './sse.js';
import { Score } from '../shared/types.js';

export const apiRouter = Router();
  // ─── Session Endpoints ───────────────────────────────────────────────

  apiRouter.get('/api/session', (_req: Request, res: Response) => {
    const session = getSession();
    res.json(session);
  });

  apiRouter.post('/api/session/start', (_req: Request, res: Response) => {
    const session = getSession();
    if (session.status === 'active') {
      res.status(400).json({ error: 'Session is already active' });
      return;
    }
    const updated = updateSession({
      status: 'active',
      startedAt: new Date().toISOString(),
    });
    res.json(updated);
  });

  apiRouter.post('/api/session/end', (_req: Request, res: Response) => {
    const session = getSession();
    if (session.status !== 'active') {
      res.status(400).json({ error: 'Session is not active' });
      return;
    }
    const updated = updateSession({
      status: 'ended',
      endedAt: new Date().toISOString(),
    });
    res.json(updated);
  });

  // ─── Team and Juror Endpoints ────────────────────────────────────────

  apiRouter.get('/api/teams', (_req: Request, res: Response) => {
    const teams = getTeams();
    res.json(teams);
  });

  apiRouter.get('/api/jurors', (_req: Request, res: Response) => {
    const jurors = getJurors();
    res.json(jurors);
  });

  // ─── Score Endpoints ─────────────────────────────────────────────────

  apiRouter.post('/api/scores', (req: Request, res: Response) => {
    const session = getSession();
    if (session.status !== 'active') {
      res.status(403).json({ error: 'Session is not active' });
      return;
    }

    const { jurorId, teamId, criterionId, value, force } = req.body;

    // Validate required fields
    if (!jurorId || !teamId || !criterionId || value === undefined) {
      res.status(400).json({ error: 'Missing required fields: jurorId, teamId, criterionId, value' });
      return;
    }

    // Validate value is within scale range
    const { scaleMin, scaleMax } = session.config;
    if (typeof value !== 'number' || value < scaleMin || value > scaleMax) {
      res.status(400).json({ error: `Value must be between ${scaleMin} and ${scaleMax}` });
      return;
    }

    // Validate jurorId exists
    const jurors = getJurors();
    if (!jurors.find((j) => j.id === jurorId)) {
      res.status(400).json({ error: `Unknown jurorId: ${jurorId}` });
      return;
    }

    // Validate teamId exists
    const teams = getTeams();
    if (!teams.find((t) => t.id === teamId)) {
      res.status(400).json({ error: `Unknown teamId: ${teamId}` });
      return;
    }

    // Validate criterionId exists
    const criteria = session.config.criteria;
    if (!criteria.find((c) => c.id === criterionId)) {
      res.status(400).json({ error: `Unknown criterionId: ${criterionId}` });
      return;
    }

    const incoming: Score = {
      jurorId,
      teamId,
      criterionId,
      value,
      updatedAt: new Date().toISOString(),
    };

    // Check for existing score and resolve conflict
    const existingScores = getScores();
    const existing = existingScores.find(
      (s) => s.jurorId === jurorId && s.teamId === teamId && s.criterionId === criterionId
    );

    const conflict = resolveConflict(incoming, existing, force);
    if (!conflict.accept) {
      res.status(409).json({ error: conflict.reason, existing });
      return;
    }

    addScore(incoming);
    broadcastUpdate();
    res.json(incoming);
  });

  apiRouter.get('/api/scores/:jurorId', (req: Request, res: Response) => {
    const { jurorId } = req.params;
    const scores = getScores();
    const jurorScores = scores.filter((s) => s.jurorId === jurorId);
    res.json(jurorScores);
  });

  apiRouter.get('/api/scores', (_req: Request, res: Response) => {
    const scores = getScores();
    res.json(scores);
  });

  // ─── Results and Progress Endpoints ──────────────────────────────────

  apiRouter.get('/api/results', (_req: Request, res: Response) => {
    const store = getStore();
    const criteriaCount = store.session.config.criteria.length;
    const results = calculateAllResults(store.scores, store.teams, criteriaCount, store.session.config.criteria);
    res.json(results);
  });

  apiRouter.get('/api/progress', (_req: Request, res: Response) => {
    const store = getStore();
    const criteriaCount = store.session.config.criteria.length;
    const progress: Record<string, { completed: number; total: number }> = {};

    for (const juror of store.jurors) {
      let completedTeams = 0;
      for (const team of store.teams) {
        const status = getCompletionStatus(juror.id, team.id, store.scores, criteriaCount);
        if (status === 'complete') {
          completedTeams++;
        }
      }
      progress[juror.id] = { completed: completedTeams, total: store.teams.length };
    }

    res.json(progress);
  });

  apiRouter.get('/api/export/csv', (_req: Request, res: Response) => {
    const store = getStore();
    const criteriaCount = store.session.config.criteria.length;
    const results = calculateAllResults(store.scores, store.teams, criteriaCount);

    // Build header row: Team, then for each juror: juror_criterion1, juror_criterion2, ..., then Total, Average, Rank
    const criteria = store.session.config.criteria;
    const headerParts = ['Team'];
    for (const juror of store.jurors) {
      for (const criterion of criteria) {
        headerParts.push(`${juror.name}_${criterion.nameDE}`);
      }
    }
    headerParts.push('Total', 'Average', 'Rank');

    const rows: string[] = [headerParts.join(',')];

    // One row per team (sorted by rank)
    for (const result of results) {
      const rowParts: string[] = [`"${result.teamName}"`];

      for (const juror of store.jurors) {
        for (const criterion of criteria) {
          const score = store.scores.find(
            (s) => s.jurorId === juror.id && s.teamId === result.teamId && s.criterionId === criterion.id
          );
          rowParts.push(score ? String(score.value) : '');
        }
      }

      rowParts.push(String(result.total), result.average.toFixed(2), String(result.rank));
      rows.push(rowParts.join(','));
    }

    const csv = rows.join('\n');
    res.setHeader('Content-Type', 'text/csv');
    res.setHeader('Content-Disposition', 'attachment; filename="jury-results.csv"');
    res.send(csv);
  });