// Copyright 2022 wanderer <a_mirre at utb dot cz>
// SPDX-License-Identifier: GPL-3.0-or-later

package algo

import (
	"fmt"
	"log"
	"sync"
	"time"

	"git.dotya.ml/wanderer/math-optim/stats"
	"git.dotya.ml/wanderer/math-optim/util"
	"gonum.org/v1/gonum/floats"
	"gonum.org/v1/plot"
	"gonum.org/v1/plot/plotter"
	"gonum.org/v1/plot/plotutil"
	"gonum.org/v1/plot/vg"
)

const preferredFontStyle = "Mono"

// violating the limit of 30, TODO(me): split this up.
// nolint: gocognit
func plotAllDims(algoStats []stats.Stats, fPrefix, fExt string, wg *sync.WaitGroup) {
	defer wg.Done() // does this work with panic in the mix? TODO(me): find out.

	start := time.Now()
	pWidth := 13 * vg.Centimeter
	pHeight := 13 * vg.Centimeter

	plotter.DefaultFont.Typeface = preferredFontStyle
	plotter.DefaultLineStyle.Width = vg.Points(1.5)

	for _, s := range algoStats {
		p := plot.New()
		p.Title.Text = s.Algo + ", D=" + fmt.Sprint(s.Dimens) +
			", func=" + s.BenchFuncStats[0].BenchName +
			", G=" + fmt.Sprint(s.Generations) +
			", I=" + fmt.Sprint(s.Iterations)
		p.X.Label.Text = "Generations"
		p.X.Label.TextStyle.Font.Variant = preferredFontStyle
		p.X.Label.TextStyle.Font.Weight = 1 // Medium
		p.X.Tick.Label.Font.Variant = preferredFontStyle
		p.Y.Label.Text = "CF value"
		p.Y.Label.TextStyle.Font.Variant = preferredFontStyle
		p.Y.Label.TextStyle.Font.Weight = 1 // Medium
		p.Y.Tick.Label.Font.Variant = preferredFontStyle

		p.Title.TextStyle.Font.Size = 11.5
		p.Title.TextStyle.Font.Variant = "Sans"
		p.Title.TextStyle.Font.Weight = 2 // SemiBold
		p.Title.Padding = 5 * vg.Millimeter

		for _, dim := range s.BenchFuncStats {
			// infinite thanks to this SO comment for the interface "hack":
			//   https://stackoverflow.com/a/44872993
			lines := make([]interface{}, 0)

			for _, iter := range dim.Solution {
				// mark the end of the X axis with len(iter.Results).
				p.X.Max = float64(len(iter.Results))

				if floats.Min(iter.Results) < p.Y.Min {
					p.Y.Min = floats.Min(iter.Results)
				}

				if floats.Max(iter.Results) > p.Y.Max {
					p.Y.Max = floats.Max(iter.Results)
				}

				pts := make(plotter.XYs, len(iter.Results))

				// fill the plotter with datapoints.
				for k, res := range iter.Results {
					pts[k].X = float64(k)
					pts[k].Y = res
				}

				lines = append(lines, pts)
			}

			err := plotutil.AddLines(
				p,
				lines...,
			)
			if err != nil {
				// panic (don't panic, I know) instead of a hard exit.
				log.Panic(err)
			}

			if err := util.CreatePath(picPath); err != nil {
				log.Println(err)
			}

			filename := picPath +
				fPrefix + "-" +
				util.SanitiseFName(s.Algo) + "-" +
				util.SanitiseFName(dim.BenchName) + "-" +
				fmt.Sprint(s.Dimens) + "D-" +
				fmt.Sprint(s.Generations) + "G-" +
				fmt.Sprint(len(dim.Solution)) + "I"

			elapsed := time.Since(start)
			info := "saving img to file: " + filename + fExt +
				" [generated in " + fmt.Sprint(elapsed) + "]"

			if s.Algo == "Random Search" {
				printRandomSearch(info)
			} else {
				printSHC(info)
			}

			// Save the plot to a file using the above-constructed 'filename'.
			if err := p.Save(
				pWidth,
				pHeight,
				filename+fExt,
			); err != nil {
				panic(err)
			}
		}
	}
}