package main

import (
	"context"
	"database/sql"
	"fmt"
	"iter"
	"os"
	"strings"
	"sync"

	_ "embed"

	_ "github.com/mattn/go-sqlite3"
	"github.com/uptrace/opentelemetry-go-extra/otelsql"
	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
	"go.sour.is/xt/internal/otel"
	"go.yarn.social/lextwt"
	"go.yarn.social/types"
	"golang.org/x/sync/errgroup"
)

func run(c *console) error {
	ctx, span := otel.Span(c.Context)
	defer span.End()

	a := c.Args()
	app := &appState{
		args:  a,
		feeds: sync.Map{},
		queue: FibHeap(func(a, b *Feed) bool {
			return a.LastScanOn.Time.Before(b.LastScanOn.Time)
		}),
	}

	// Setup DB
	err := func(ctx context.Context) error {
		ctx, span := otel.Span(ctx)
		defer span.End()

		db, err := app.DB()
		if err != nil {
			return err
		}
		defer db.Close()

		for _, stmt := range strings.Split(initSQL, ";") {
			_, err = db.ExecContext(ctx, stmt)
			if err != nil {
				return err
			}
		}

		return nil
	}(ctx)
	if err != nil {
		return err
	}

	// Seed File
	err = func(ctx context.Context) error {
		ctx, span := otel.Span(ctx)
		defer span.End()

		f, err := os.Open(a.baseFeed)
		if err != nil {
			return err
		}
		defer f.Close()

		twtfile, err := lextwt.ParseFile(f, &types.Twter{
			Nick: a.Nick,
			URI:  a.URI,
		})
		if err != nil {
			return fmt.Errorf("%w: %w", ErrParseFailed, err)
		}

		db, err := app.DB()
		if err != nil {
			return err
		}
		defer db.Close()

		return storeFeed(ctx, db, twtfile)
	}(ctx)
	if err != nil {
		return err
	}

	wg, ctx := errgroup.WithContext(ctx)
	c.Context = ctx

	wg.Go(func() error { return refreshLoop(c, app) })
	go httpServer(c, app)

	wg.Wait()
	return c.Context.Err()
}

type appState struct {
	args  args
	feeds sync.Map
	queue *fibHeap[Feed]
}

func (app *appState) DB() (*sql.DB, error) {
	// return sql.Open(app.args.dbtype, app.args.dbfile)

	return otelsql.Open(app.args.dbtype, app.args.dbfile,
		otelsql.WithAttributes(semconv.DBSystemSqlite),
		otelsql.WithDBName("mydb"))
}

func (app *appState) Feed(feedID string) *Feed {
	return nil
}

func (app *appState) Feeds() iter.Seq2[string, *Feed] {
	return func(yield func(string, *Feed) bool) {
		app.feeds.Range(func(k, v any) bool {
			key, _ := k.(string)
			value, ok := v.(*Feed)
			if !ok {
				return false
			}
			if !yield(key, value) {
				return false
			}
			return true
		})
	}
}