// This is all because I don't want to deal with double-escaping regex special
// characters in sh.
package main

import (
	"log"
	"os"
	"path/filepath"
	"regexp"
)

func mapSlice[A, B any](f func(A) B, a []A) []B {
	b := make([]B, len(a))
	for i := range b {
		b[i] = f(a[i])
	}
	return b
}

type Replacer struct {
	re          *regexp.Regexp
	replacement string
}

func compile(raw [2]string) Replacer {
	return Replacer{
		re:          regexp.MustCompile(raw[0]),
		replacement: raw[1],
	}
}

var replacers = mapSlice(compile, [][2]string{
	// Chapter titles
	{`CHAPTER [IVX]+\.` + "\n\n" + `(.*)\.`, `# $1`},

	// Section titles
	{`(?ms)SECTION [IVX]+\.\n\n_([^_]+)\._`, `## $1`},

	// Untitled sections
	{`SECTION [IVX]+\.`, `<h2></h2>`},

	// Em dashes
	{"--", "—"},

	// Left double typographical quote
	{`"(\w|_\w)`, `“$1`},

	// Right double typographical quote
	{`"`, `”`},

	// Footnote superscripts
	{`\[(\d+)\]`, `[^$1]`},

	// Left single typographical quote
	{`([^\pL])'(\pL|_)`, `$1‘$2`},
	{`(?m)^'`, `‘`},

	// Right single typographical quote
	{`'`, `’`},

	// Block quotes
	{`(?m)^ +(\S)`, `> $1`},
})

func run() error {
	paths, err := filepath.Glob("original/*.markdown")
	if err != nil {
		return err
	}
	for _, path := range paths {
		b, err := os.ReadFile(path)
		if err != nil {
			return err
		}
		var edited = b
		for _, r := range replacers {
			edited = r.re.ReplaceAll(edited, []byte(r.replacement))
		}
		outpath := filepath.Join("edited", filepath.Base(path))
		err = os.WriteFile(outpath, edited, 0666)
		if err != nil {
			return err
		}
	}
	return nil
}

func main() {
	err := run()
	if err != nil {
		log.Fatal(err)
	}
}