<?php
/**
 * GlManager
 *
 * Owns all read/write operations on td_gl and td_gl_item.
 * Called by PostingEngine after building the journal lines.
 *
 * Lifecycle:
 *   post()    — first-time GL creation; throws if a record already exists.
 *   replace() — snapshot current lines into td_gl.history, then delete + re-insert.
 *   delete()  — create a reversal journal entry (debit/credit swapped), then mark the original
 *               source_type = 'voided' so it stays in the table for audit trail but is invisible
 *               to getBySource() lookups.
 */
class GlManager
{
    private PDO $pdo;
    private int $companyId;
    private ?PostingWindowGuard $postingWindowGuard;

    public function __construct(PDO $pdo, int $company_id, ?PostingWindowGuard $postingWindowGuard = null)
    {
        $this->pdo                = $pdo;
        $this->companyId          = $company_id;
        $this->postingWindowGuard = $postingWindowGuard;
    }

    // ── public ───────────────────────────────────────────────────────────────

    public function getBySource(string $source_type, int $source_id): ?array
    {
        $sth = $this->pdo->prepare(
            "SELECT * FROM td_gl
             WHERE company_id  = :cid
               AND source_type = :source_type
               AND source_id   = :source_id
             LIMIT 1"
        );
        $sth->execute([
            ':cid'         => $this->companyId,
            ':source_type' => $source_type,
            ':source_id'   => $source_id,
        ]);
        return $sth->fetch(PDO::FETCH_ASSOC) ?: null;
    }

    public function post(string $source_type, int $source_id, int $formula_id, string $period, array $lines, array $meta = []): void
    {
        $journal_date = $this->resolveJournalDate($meta['journal_date'] ?? null, $period);
        $this->assertPostingWindow($journal_date, 'GL posting');

        $now = date('Y-m-d H:i:s');
        $sth = $this->pdo->prepare(
            "INSERT INTO td_gl
                (company_id, source_type, source_id, reference, description, journal_date,
                 formula_id, period, current_version, history, created_at, updated_at)
             VALUES
                (:cid, :source_type, :source_id, :reference, :description, :journal_date,
                 :formula_id, :period, 1, '[]', :created_at, :updated_at)"
        );
        $sth->execute([
            ':cid'          => $this->companyId,
            ':source_type'  => $source_type,
            ':source_id'    => $source_id,
            ':reference'    => $meta['reference']    ?? '',
            ':description'  => $meta['description']  ?? '',
            ':journal_date' => $journal_date,
            ':formula_id'   => $formula_id,
            ':period'       => $period,
            ':created_at'   => $now,
            ':updated_at'   => $now,
        ]);
        $this->insertLines((int)$this->pdo->lastInsertId(), $lines);
        $this->upsertEtl($lines, $period);
    }

    public function replaceManual(int $gl_id, string $reference, string $description, string $journal_date, string $period, array $lines): void
    {
        $this->assertPostingWindow($journal_date, 'Manual journal');

        $now = date('Y-m-d H:i:s');

        $sth = $this->pdo->prepare(
            "SELECT id, current_version, formula_id, history
             FROM td_gl
             WHERE company_id = :cid AND id = :gl_id AND source_type = 'manual'
             FOR UPDATE"
        );
        $sth->execute([':cid' => $this->companyId, ':gl_id' => $gl_id]);
        $gl = $sth->fetch(PDO::FETCH_ASSOC);
        if (!$gl) throw new Exception("Manual GL entry #$gl_id not found.");

        $version = (int)$gl['current_version'];
        $history = json_decode($gl['history'], true) ?: [];

        $history[] = [
            'version'     => $version,
            'formula_id'  => 0,
            'replaced_at' => $now,
            'lines'       => $this->getLines($gl_id),
        ];

        $old_lines  = $history[count($history) - 1]['lines'];  // captured just above
        $old_period = $gl['period'];

        $this->pdo->prepare(
            "DELETE FROM td_gl_item WHERE company_id = :cid AND gl_id = :gl_id"
        )->execute([':cid' => $this->companyId, ':gl_id' => $gl_id]);

        $this->pdo->prepare(
            "UPDATE td_gl
             SET reference = :reference, description = :description,
                 journal_date = :journal_date, period = :period,
                 current_version = :current_version, history = :history,
                 updated_at = :updated_at
             WHERE id = :id"
        )->execute([
            ':reference'       => $reference,
            ':description'     => $description,
            ':journal_date'    => $journal_date,
            ':period'          => $period,
            ':current_version' => $version + 1,
            ':history'         => json_encode($history),
            ':updated_at'      => $now,
            ':id'              => $gl_id,
        ]);

        $this->insertLines($gl_id, $lines);
        $this->upsertEtl($old_lines, $old_period, -1);
        $this->upsertEtl($lines, $period);
    }

    public function postManual(string $reference, string $description, string $journal_date, string $period, array $lines): int
    {
        $this->assertPostingWindow($journal_date, 'Manual journal');

        $now = date('Y-m-d H:i:s');
        $sth = $this->pdo->prepare(
            "INSERT INTO td_gl
                (company_id, source_type, source_id, reference, description, journal_date,
                 formula_id, period, current_version, history, created_at, updated_at)
             VALUES
                (:cid, 'manual', 0, :reference, :description, :journal_date,
                 0, :period, 1, '[]', :created_at, :updated_at)"
        );
        $sth->execute([
            ':cid'          => $this->companyId,
            ':reference'    => $reference,
            ':description'  => $description,
            ':journal_date' => $journal_date,
            ':period'       => $period,
            ':created_at'   => $now,
            ':updated_at'   => $now,
        ]);
        $gl_id = (int)$this->pdo->lastInsertId();
        $this->insertLines($gl_id, $lines);
        $this->upsertEtl($lines, $period);
        return $gl_id;
    }

    public function replace(string $source_type, int $source_id, int $formula_id, string $period, array $lines, array $meta = []): void
    {
        $now = date('Y-m-d H:i:s');

        $sth = $this->pdo->prepare(
            "SELECT id, current_version, formula_id, history, journal_date
             FROM td_gl
             WHERE company_id  = :cid
               AND source_type = :source_type
               AND source_id   = :source_id
             FOR UPDATE"
        );
        $sth->execute([
            ':cid'         => $this->companyId,
            ':source_type' => $source_type,
            ':source_id'   => $source_id,
        ]);
        $gl = $sth->fetch(PDO::FETCH_ASSOC);
        if (!$gl) throw new Exception("GL record not found for replace.");

        $journal_date = $this->resolveJournalDate($meta['journal_date'] ?? ($gl['journal_date'] ?? null), $period);
        $this->assertPostingWindow($journal_date, 'GL posting');

        $gl_id   = (int)$gl['id'];
        $version = (int)$gl['current_version'];
        $history = json_decode($gl['history'], true) ?: [];

        // Snapshot current lines into history
        $old_lines  = $this->getLines($gl_id);
        $old_period = $gl['period'];

        $history[] = [
            'version'     => $version,
            'formula_id'  => (int)$gl['formula_id'],
            'replaced_at' => $now,
            'lines'       => $old_lines,
        ];

        $this->pdo->prepare(
            "DELETE FROM td_gl_item WHERE company_id = :cid AND gl_id = :gl_id"
        )->execute([':cid' => $this->companyId, ':gl_id' => $gl_id]);

        $this->pdo->prepare(
            "UPDATE td_gl
             SET formula_id      = :formula_id,
                 journal_date    = :journal_date,
                 period          = :period,
                 current_version = :current_version,
                 history         = :history,
                 updated_at      = :updated_at
             WHERE id = :id"
        )->execute([
            ':formula_id'      => $formula_id,
            ':journal_date'    => $journal_date,
            ':period'          => $period,
            ':current_version' => $version + 1,
            ':history'         => json_encode($history),
            ':updated_at'      => $now,
            ':id'              => $gl_id,
        ]);

        $this->insertLines($gl_id, $lines);
        $this->upsertEtl($old_lines, $old_period, -1);
        $this->upsertEtl($lines, $period);
    }

    public function delete(string $source_type, int $source_id): void
    {
        $sth = $this->pdo->prepare(
            "SELECT id, reference, description, journal_date, period, formula_id
             FROM td_gl
             WHERE company_id  = :cid
               AND source_type = :source_type
               AND source_id   = :source_id
             LIMIT 1"
        );
        $sth->execute([
            ':cid'         => $this->companyId,
            ':source_type' => $source_type,
            ':source_id'   => $source_id,
        ]);
        $gl = $sth->fetch(PDO::FETCH_ASSOC);
        $gl_id = (int)($gl['id'] ?? 0);
        if (!$gl_id) return;

        $journal_date = $this->resolveJournalDate($gl['journal_date'] ?? null, (string)($gl['period'] ?? ''));
        $this->assertPostingWindow($journal_date, 'GL void');

        $original_lines = $this->getLines($gl_id);

        if (!empty($original_lines)) {
            $reversal_lines = array_map(fn($line) => [
                'account_code'  => $line['account_code'],
                'department_id' => (int)$line['department_id'],
                'debit'         => (float)$line['credit'],
                'credit'        => (float)$line['debit'],
                'description'   => 'VOID: ' . $line['description'],
            ], $original_lines);

            $now = date('Y-m-d H:i:s');
            $this->pdo->prepare(
                "INSERT INTO td_gl
                    (company_id, source_type, source_id, reference, description, journal_date,
                     formula_id, period, current_version, history, created_at, updated_at)
                 VALUES
                    (:cid, 'reversal', :source_id, :reference, :description, :journal_date,
                     :formula_id, :period, 1, '[]', :created_at, :updated_at)"
            )->execute([
                ':cid'          => $this->companyId,
                ':source_id'    => $gl_id,
                ':reference'    => 'VOID/' . ($gl['reference'] ?? ''),
                ':description'  => 'Void: ' . ($gl['description'] ?? ''),
                ':journal_date' => $journal_date,
                ':formula_id'   => (int)($gl['formula_id'] ?? 0),
                ':period'       => $gl['period'] ?? '',
                ':created_at'   => $now,
                ':updated_at'   => $now,
            ]);
            $reversal_gl_id = (int)$this->pdo->lastInsertId();
            $this->insertLines($reversal_gl_id, $reversal_lines);
            $this->upsertEtl($reversal_lines, $gl['period']);
        }

        // Mark original as voided — keeps audit trail; getBySource() won't match 'voided' source_type
        $this->pdo->prepare(
            "UPDATE td_gl SET source_type = 'voided', updated_at = NOW()
             WHERE id = :id AND company_id = :cid"
        )->execute([':id' => $gl_id, ':cid' => $this->companyId]);
    }

    // ── private ──────────────────────────────────────────────────────────────

    private function getLines(int $gl_id): array
    {
        $sth = $this->pdo->prepare(
            "SELECT account_code, department_id, debit, credit, description
             FROM td_gl_item
             WHERE company_id = :cid AND gl_id = :gl_id
             ORDER BY id ASC"
        );
        $sth->execute([':cid' => $this->companyId, ':gl_id' => $gl_id]);
        return $sth->fetchAll(PDO::FETCH_ASSOC);
    }

    private function assertPostingWindow(?string $journal_date, string $context): void
    {
        if ($this->postingWindowGuard) {
            $this->postingWindowGuard->assertOpenDate($journal_date, $context);
        }
    }

    private function resolveJournalDate(?string $journal_date, string $period): string
    {
        $journal_date = trim((string)$journal_date);
        if ($journal_date !== '') {
            return $journal_date;
        }

        $period = trim($period);
        return preg_match('/^\d{4}-\d{2}$/', $period) ? "{$period}-01" : '';
    }

    private function insertLines(int $gl_id, array $lines): void
    {
        $sth = $this->pdo->prepare(
            "INSERT INTO td_gl_item
                (company_id, gl_id, account_code, department_id, debit, credit, description)
             VALUES
                (:cid, :gl_id, :account_code, :dept_id, :debit, :credit, :description)"
        );
        foreach ($lines as $line) {
            $sth->execute([
                ':cid'          => $this->companyId,
                ':gl_id'        => $gl_id,
                ':account_code' => $line['account_code'],
                ':dept_id'      => (int)($line['department_id'] ?? 0),
                ':debit'        => (float)($line['debit'] ?? 0),
                ':credit'       => (float)($line['credit'] ?? 0),
                ':description'  => (string)($line['description'] ?? ''),
            ]);
        }
    }

    // sign=1 to add, sign=-1 to subtract (used when replacing old lines)
    private function upsertEtl(array $lines, string $period, int $sign = 1): void
    {
        if (empty($lines) || empty($period)) return;

        $sth = $this->pdo->prepare(
            "INSERT INTO etl_gl_summary
                (company_id, acc_code, period, debit, credit, count, updated_at)
             VALUES
                (:cid, :acc, :period, :debit, :credit, :cnt, NOW())
             ON DUPLICATE KEY UPDATE
                debit      = debit      + VALUES(debit),
                credit     = credit     + VALUES(credit),
                count      = count      + VALUES(count),
                updated_at = NOW()"
        );
        foreach ($lines as $line) {
            $sth->execute([
                ':cid'    => $this->companyId,
                ':acc'    => (int)($line['account_code'] ?? 0),
                ':period' => $period,
                ':debit'  => (float)($line['debit']  ?? 0) * $sign,
                ':credit' => (float)($line['credit'] ?? 0) * $sign,
                ':cnt'    => $sign,
            ]);
        }
    }
}