package main

import (
	"context"
	_ "embed"
	"errors"
	"io"
	"text/template"
	"time"
)

//go:embed report.tmpl
var reportTMPL string

func ReportSince(ctx context.Context, w io.Writer, s Storage, t time.Time) error {
	tmpl := template.New("report").Funcs(map[string]any{
		"time": func(foo string, args ...any) (any, error) {
			switch foo {
			case "Unix":
				seconds, _ := args[0].(uint64)
				return time.Unix(int64(seconds), 0), nil
			case "Time.Format":
				t, _ := args[1].(time.Time)
				return t.Format(args[0].(string)), nil
			}
			return nil, errors.New("not impl")
		},
		"null": func() any {
			return nil
		},
		"append": func(arr any, v any) (any, error) {
			if v == nil {
				return arr, nil
			}
			switch arr := arr.(type) {
			case []any:
				return append(arr, v), nil
			case nil:
				return []any{v}, nil
			}
			return nil, errors.New("unknown type in append")
		},
	})
	tmpl, err := tmpl.Parse(reportTMPL)
	if err != nil {
		return err
	}

	messages, err := s.MessagesSince(ctx, t)
	if err != nil {
		return err
	}

	threads, err := s.ThreadsSince(ctx, t)
	if err != nil {
		return err
	}

	eventNames, err := s.EventNamesSince(ctx, t)
	if err != nil {
		return err
	}

	events, err := s.EventsSince(ctx, t)
	if err != nil {
		return err
	}

	return tmpl.Execute(w, map[string]any{
		"since":      t.Format("2006-01-02"),
		"messages":   messages,
		"threads":    threads,
		"events":     events,
		"eventNames": eventNames,
	})
}