#!/usr/bin/env python3
"""Firm x year descriptor trends (B-gate diagnostic).

Plots per-firm yearly mean cosine, mean dHash, and HC-box hit share to test
whether Firms B/C/D show a 2020 structural break converging toward Firm A.
Read-only against the production DB.
"""
import sqlite3
import matplotlib.pyplot as plt

DB = '/Volumes/NV2/PDF-Processing/signature-analysis/signature_analysis.db'
FIRMS = [('勤業眾信聯合', 'Firm A (Deloitte)', '#d62728'),
         ('安侯建業聯合', 'Firm B (KPMG)', '#1f77b4'),
         ('資誠聯合', 'Firm C (PwC)', '#2ca02c'),
         ('安永聯合', 'Firm D (EY)', '#ff7f0e')]

conn = sqlite3.connect(f'file:{DB}?mode=ro', uri=True)
cur = conn.cursor()


def series(firm_zh):
    cur.execute("""
        SELECT CAST(substr(s.year_month,1,4) AS INT) AS yr,
               AVG(s.max_similarity_to_same_accountant),
               AVG(s.min_dhash_independent),
               AVG(CASE WHEN s.max_similarity_to_same_accountant>0.95
                         AND s.min_dhash_independent<=5 THEN 1.0 ELSE 0.0 END),
               COUNT(*)
        FROM signatures s JOIN accountants a ON s.assigned_accountant=a.name
        WHERE a.firm=? AND s.year_month IS NOT NULL
          AND s.max_similarity_to_same_accountant IS NOT NULL
          AND s.min_dhash_independent IS NOT NULL
        GROUP BY yr ORDER BY yr""", (firm_zh,))
    return cur.fetchall()


fig, axes = plt.subplots(1, 3, figsize=(16, 4.8))
for firm_zh, label, color in FIRMS:
    rows = series(firm_zh)
    yrs = [r[0] for r in rows]
    axes[0].plot(yrs, [r[1] for r in rows], 'o-', color=color, label=label)
    axes[1].plot(yrs, [r[2] for r in rows], 'o-', color=color, label=label)
    axes[2].plot(yrs, [r[3] for r in rows], 'o-', color=color, label=label)

for ax in axes:
    ax.axvline(2020, ls='--', color='grey', alpha=0.6)
    ax.text(2020.05, ax.get_ylim()[0], ' 2020', color='grey', fontsize=8, va='bottom')
    ax.set_xlabel('Fiscal year')
    ax.grid(alpha=0.3)
axes[0].set_title('Mean best-match cosine'); axes[0].axhline(0.95, ls=':', color='k', alpha=0.4)
axes[1].set_title('Mean independent-min dHash'); axes[1].axhline(5, ls=':', color='k', alpha=0.4)
axes[2].set_title('HC-box share (cos>0.95 & dHash$\\leq$5)')
axes[0].legend(fontsize=8, loc='lower right')
fig.suptitle('Big-4 descriptor trends 2013–2023 (2023 = partial, to Apr)  —  no 2020 break, no convergence to A',
             fontsize=11)
fig.tight_layout()
out = '/Volumes/NV2/pdf_recognize/signature_analysis/firm_year_trends.png'
fig.savefig(out, dpi=130, bbox_inches='tight')
print('saved', out)
conn.close()