using Unitful
using DataFrames
using Plots
using UnitfulRecipes
using Roots
using CSV


# Tank https://www.amazon.com/Empire-Paintball-BASICS-Pressure-Compressed/dp/B07B6M48SR/
V = 90u"inch^3"
P0 = 4500.0u"psi"
Wtank = 2.3u"lb"
Pmax = 100u"psi"

Wsolenoid = 1.5u"kg"

# Params
d_nozzle = (1 // 16) * u"inch"
a_nozzle = (pi / 4) * d_nozzle^2
Poutmax = 800u"psi"

# Universal Stuff
P_amb = 1u"atm"
γ = 1.4
R = 287.05u"J/(kg * K)"
T = 300u"K"

# Setting up while loop
t = 1.0u"s"
P = P0 |> u"Pa"
M = V * (P / (R * T)) |> u"kg"
df = DataFrame(Thrust = 0.0u"N", Pressure = P, Time = t, Mass = M)
ts = 0.001u"s"
while M > 0.01u"kg"
    # while t < 30u"s"
    # Calculate what is leaving tank
    P = minimum([P, Pmax])
    ve = sqrt((2 * γ / (γ - 1)) * R * T * (1 - P_amb / P)^((γ - 1) / γ)) |> u"m/s"
    ρ = P / (R * T) |> u"kg/m^3"
    ṁ = ρ * a_nozzle * ve |> u"kg/s"

    Thrust = ṁ * ve + a_nozzle * (P - P_amb) |> u"N"

    # Calculate what is still in the tank
    M = M - ṁ * ts |> u"kg"
    P = (M * R * T) / V |> u"Pa"
    t = t + ts

    df_step = DataFrame(Thrust = Thrust, Pressure = P, Time = t, Mass = M)
    append!(df, df_step)
end
println("---------------------------\n\n\n\n")
println("Total Impulse: ", sum(df.Thrust) * ts)
println("Burn Time: ", t)
println("Mass Total: ", Wtank + Wsolenoid + maximum(df.Mass))

print(describe(df))
plot(df.Time, df.Thrust, title = "Thrust Over Time")
CSV.write("thrustdata.csv", df .|> ustrip)