//go:build ignore

// genlect generates the EF temporal Sunday lectionary from missalemeum
// (Divinum Officium data), keyed by lectio's computed temporal-day slug.
// One-time; requires network. Run from the repo root:
//   go run scripts/genlect.go
// Writes internal/caldata/tridentine-lectionary.ini.
package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"regexp"
	"sort"
	"strings"
	"time"

	"github.com/lukaszkasprzak/lectio/internal/caldata"
	"github.com/lukaszkasprzak/lectio/internal/calendar"
)

var citeRe = regexp.MustCompile(`\*([^*]+)\*`)

func fetchCitations(date string) (epistle, gospel string) {
	resp, err := http.Get("https://www.missalemeum.com/en/api/v5/proper/" + date)
	if err != nil {
		return
	}
	defer resp.Body.Close()
	var data []struct {
		Sections []struct {
			ID   string     `json:"id"`
			Body [][]string `json:"body"` // [[english, latin]]
		} `json:"sections"`
	}
	if json.NewDecoder(resp.Body).Decode(&data) != nil || len(data) == 0 {
		return
	}
	for _, s := range data[0].Sections {
		if len(s.Body) == 0 || len(s.Body[0]) == 0 {
			continue
		}
		m := citeRe.FindStringSubmatch(s.Body[0][0]) // english text carries *citation*
		if m == nil {
			continue
		}
		switch s.ID {
		case "Lectio":
			epistle = strings.TrimSpace(m[1])
		case "Evangelium":
			gospel = strings.TrimSpace(m[1])
		}
	}
	return
}

func main() {
	sel := calendar.DefaultSelection()
	sel.Form = "old"
	layers := []calendar.Layer{caldata.Tridentine()}
	lect := map[string][2]string{} // slug -> {epistle, gospel}

	start := time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC)
	end := time.Date(2028, 12, 31, 0, 0, 0, 0, time.UTC)
	for d := start; !d.After(end); d = d.AddDate(0, 0, 1) {
		if d.Weekday() != time.Sunday {
			continue
		}
		day := calendar.Compute(d, sel, layers)
		if day.Observed.Layer != "temporal" { // a feast won that Sunday -> its own propers
			continue
		}
		slug := day.Observed.Slug
		if _, ok := lect[slug]; ok {
			continue // one instance per slug
		}
		ep, gos := fetchCitations(d.Format("2006-01-02"))
		if ep == "" && gos == "" {
			continue
		}
		lect[slug] = [2]string{ep, gos}
		fmt.Fprintf(os.Stderr, "%s %-34s ep=%-22s go=%s\n", d.Format("2006-01-02"), slug, ep, gos)
	}

	slugs := make([]string, 0, len(lect))
	for s := range lect {
		slugs = append(slugs, s)
	}
	sort.Strings(slugs)
	var b strings.Builder
	b.WriteString("; EF (1962) temporal lectionary, keyed by lectio's computed temporal-day slug.\n")
	b.WriteString("; Generated from missalemeum (Divinum Officium). Epistle (first) + Gospel citations.\n")
	for _, s := range slugs {
		v := lect[s]
		fmt.Fprintf(&b, "\n[%s]\n", s)
		if v[0] != "" {
			fmt.Fprintf(&b, "first = %s\n", v[0])
		}
		if v[1] != "" {
			fmt.Fprintf(&b, "gospel = %s\n", v[1])
		}
	}
	if err := os.WriteFile("internal/caldata/tridentine-lectionary.ini", []byte(b.String()), 0o644); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
	fmt.Fprintf(os.Stderr, "wrote %d temporal entries\n", len(lect))
}