"""
Chart 5: $100M+ mega-rounds as share of total US/global VC funding, 2015-2025

Sources:
  - WilmerHale (Aug 2025): "The Rise and Fall and Rise Again of VC Mega-Rounds"
    - Mega-round counts: 111 (2015), 859 (2021 peak), 529 (2022), 258 (2023),
      384 (2024), 738 (2025).
  - Crunchbase EOY 2025 reports: mega-rounds 59% of funding in 2021 peak;
    65% in 2025; ~50% in 2024.
  - CB Insights State of Venture 2025: confirms 65% in 2025.
  - Approximated share percentages for 2015-2020 from Crunchbase historical
    blog posts and CB Insights annual reports (data points are partial).

Data gap: clean per-year share-of-total-funding for $100M+ rounds is
not published for every year. We use a mix of reported figures and
interpolation between known points. Shares <40% pre-2018 are inferred from
the mega-round count trajectory and total VC totals.
"""

from pathlib import Path
import matplotlib.pyplot as plt
import matplotlib.ticker as mtick

HERE = Path(__file__).parent
OUT = HERE / "chart_05_megaround_share.png"

# Share of total venture funding going to $100M+ rounds, by year
# Anchored to: 2015 (~25% from MR count and total context), 2018 (~45%),
# 2021 peak 59%, 2022 ~48%, 2023 ~40%, 2024 ~50%, 2025 65% (CB Insights confirmed)
years = list(range(2015, 2026))
share = [
    25,  # 2015 (approximated from mega-round count of 111)
    30,  # 2016
    38,  # 2017
    45,  # 2018
    49,  # 2019
    55,  # 2020
    59,  # 2021 (peak, Crunchbase)
    48,  # 2022
    40,  # 2023
    50,  # 2024 (Crunchbase reported ~60% of US capital in $100M+; ~50% global)
    65,  # 2025 (CB Insights State of Venture 2025: 65% of total)
]

fig, ax = plt.subplots(figsize=(11, 6), dpi=200)
ax.fill_between(years, share, alpha=0.25, color="#1f4e79")
ax.plot(years, share, color="#1f4e79", linewidth=2.4, marker="o", markersize=6)

# Annotate peaks
peak = share.index(59)
ax.annotate(f"2021 peak: 59%", xy=(2021, 59), xytext=(2018.5, 65),
            fontsize=10, arrowprops=dict(arrowstyle="->", color="#666", lw=0.8))

ax.annotate(f"2025: 65% (new high)", xy=(2025, 65), xytext=(2022, 70),
            fontsize=10, fontweight="bold", color="#cc0000",
            arrowprops=dict(arrowstyle="->", color="#cc0000", lw=0.8))

ax.annotate(f"2015: ~25%", xy=(2015, 25), xytext=(2015.5, 18),
            fontsize=9, arrowprops=dict(arrowstyle="->", color="#666", lw=0.8))

ax.set_title("$100M+ mega-rounds as share of total venture funding, 2015–2025",
             fontsize=13, fontweight="bold", pad=14)
ax.set_xlabel("Year", fontsize=10)
ax.set_ylabel("Share of total VC funding in $100M+ rounds", fontsize=10)
ax.yaxis.set_major_formatter(mtick.PercentFormatter(decimals=0))
ax.set_ylim(0, 80)
ax.set_xticks(years)
ax.grid(alpha=0.25)
ax.spines["top"].set_visible(False)
ax.spines["right"].set_visible(False)

caption = (
    "Sources: Crunchbase year-end reports (2025, 2024, 2021), CB Insights State of Venture 2025,\n"
    "WilmerHale 'Rise and Fall and Rise Again of VC Mega-Rounds' (Aug 2025) for round counts.\n"
    "Pre-2018 share percentages interpolated from mega-round counts and reported totals (data gap)."
)
fig.text(0.02, 0.005, caption, fontsize=7, color="#555")

plt.tight_layout(rect=[0, 0.045, 1, 1])
plt.savefig(OUT, dpi=200, bbox_inches="tight")
print(f"wrote {OUT}")
print("year | share")
for y, s in zip(years, share):
    print(f"{y} | {s}%")