package pdf

import (
	"embed"
	"fmt"
	"log/slog"
	"os"
	"path/filepath"
	"text/template"
	"time"

	"codeflow.dananglin.me.uk/apollo/spruce/internal/cv"
	tf "codeflow.dananglin.me.uk/apollo/spruce/internal/templatefuncs"
)

//go:embed templates/tex/*
var templates embed.FS

// tex generates the CV document as a Tex file.
func tex(input, tempDir string, historyLimit time.Time) (string, error) {
	slog.Info("Creating the Tex file.")

	data, err := cv.NewCVFromFile(input)
	if err != nil {
		return "", fmt.Errorf("unable to create a new CV value from %s; %w", input, err)
	}

	output := filepath.Join(tempDir, "cv.tex")

	file, err := os.Create(output)
	if err != nil {
		return "", fmt.Errorf("unable to create output file %s; %w", output, err)
	}
	defer file.Close()

	fmap := template.FuncMap{
		"notLastElement":   tf.NotLastElement,
		"join":             tf.JoinSentences,
		"durationToString": tf.FormatDuration,
		"withinTimePeriod": tf.WithinTimePeriod(historyLimit),
		"location":         tf.Location,
	}

	tmpl := template.Must(template.New("cv.tmpl.tex").
		Funcs(fmap).
		Delims("<<", ">>").
		ParseFS(templates, "templates/tex/*.tmpl.tex"),
	)

	if err = tmpl.Execute(file, data); err != nil {
		return "", fmt.Errorf("unable to execute the CV template. %w", err)
	}

	slog.Info("Tex file successfully created.", "filename", output)

	return output, nil
}