package handlers

import (
	"context"
	"fmt"
	"net/http"
	"strconv"

	"git.haelnorr.com/h/golib/hws"
	"git.haelnorr.com/h/oslstats/internal/db"
	"git.haelnorr.com/h/oslstats/internal/notify"
	"git.haelnorr.com/h/oslstats/internal/respond"
	"git.haelnorr.com/h/oslstats/internal/validation"
	"git.haelnorr.com/h/oslstats/internal/view/seasonsview"
	"github.com/pkg/errors"
	"github.com/uptrace/bun"
)

func GenerateFixtures(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		getter, ok := validation.ParseFormOrNotify(s, w, r)
		if !ok {
			return
		}
		seasonShortName := getter.String("season_short_name").TrimSpace().Required().Value
		leagueShortName := getter.String("league_short_name").TrimSpace().Required().Value
		round := getter.Int("round").Required().Value
		if !getter.ValidateAndNotify(s, w, r) {
			return
		}

		var season *db.Season
		var league *db.League
		var fixtures []*db.Fixture
		if ok := conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			_, err := db.NewRound(ctx, tx, seasonShortName, leagueShortName, round, db.NewAudit(r, nil))
			if err != nil {
				if db.IsBadRequest(err) {
					respond.BadRequest(w, errors.Wrap(err, "db.NewRound"))
					return false, nil
				}
				return false, errors.Wrap(err, "db.NewRound")
			}
			season, league, fixtures, err = db.GetFixtures(ctx, tx, seasonShortName, leagueShortName)
			if err != nil {
				return false, errors.Wrap(err, "db.GetFixtures")
			}
			return true, nil
		}); !ok {
			return
		}

		renderSafely(seasonsview.SeasonLeagueManageFixtures(season, league, fixtures), s, r, w)
	})
}

func UpdateFixtures(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		getter, ok := validation.ParseFormOrNotify(s, w, r)
		if !ok {
			return
		}
		seasonShortName := getter.String("season_short_name").TrimSpace().Required().Value
		leagueShortName := getter.String("league_short_name").TrimSpace().Required().Value
		allocations := getter.GetMaps("allocations")
		if !getter.ValidateAndNotify(s, w, r) {
			w.WriteHeader(http.StatusBadRequest)
			return
		}
		updates, err := mapUpdates(allocations)
		if err != nil {
			respond.BadRequest(w, errors.Wrap(err, "strconv.Atoi"))
			return
		}

		var fixtures []*db.Fixture

		if !conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			var err error
			_, _, fixtures, err = db.GetFixtures(ctx, tx, seasonShortName, leagueShortName)
			if err != nil {
				if db.IsBadRequest(err) {
					respond.BadRequest(w, errors.Wrap(err, "db.NewRound"))
					return false, nil
				}
				return false, errors.Wrap(err, "db.GetFixtures")
			}
			var valid bool
			fixtures, valid = updateFixtures(fixtures, updates)
			fmt.Println(len(fixtures))
			if !valid {
				notify.Warn(s, w, r, "Invalid game weeks", "A game week is missing or has no games", nil)
				return false, nil
			}
			err = db.UpdateFixtureGameWeeks(ctx, tx, fixtures, db.NewAudit(r, nil))
			if err != nil {
				if db.IsBadRequest(err) {
					respond.BadRequest(w, errors.Wrap(err, "db.UpdateFixtureGameWeeks"))
				}
				return false, errors.Wrap(err, "db.UpdateFixtureGameWeeks")
			}
			return true, nil
		}) {
			return
		}
		notify.Success(s, w, r, "Fixtures Updated", "Fixtures successfully updated", nil)
	})
}

func DeleteFixture(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fixtureIDstr := r.PathValue("fixture_id")
		fixtureID, err := strconv.Atoi(fixtureIDstr)
		if err != nil {
			respond.BadRequest(w, errors.Wrap(err, "strconv.Atoi"))
			return
		}
		if !conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			err := db.DeleteFixture(ctx, tx, fixtureID, db.NewAudit(r, nil))
			if err != nil {
				if db.IsBadRequest(err) {
					respond.NotFound(w, errors.Wrap(err, "db.DeleteFixture"))
					return false, nil
				}
				return false, errors.Wrap(err, "db.DeleteFixture")
			}
			return true, nil
		}) {
			return
		}
	})
}

func mapUpdates(allocations []map[string]string) (map[int]int, error) {
	updates := map[int]int{}
	for _, v := range allocations {
		id, err := strconv.Atoi(v["id"])
		if err != nil {
			return nil, errors.Wrap(err, "strconv.Atoi")
		}
		gameWeek, err := strconv.Atoi(v["game_week"])
		if err != nil {
			return nil, errors.Wrap(err, "strconv.Atoi")
		}
		updates[id] = gameWeek
	}
	return updates, nil
}

func updateFixtures(fixtures []*db.Fixture, updates map[int]int) ([]*db.Fixture, bool) {
	updated := []*db.Fixture{}
	gameWeeks := map[int]int{}
	for _, fixture := range fixtures {
		if gameWeek, exists := updates[fixture.ID]; exists {
			var newValue *int
			var oldValue int
			if fixture.GameWeek != nil {
				oldValue = *fixture.GameWeek
			} else {
				oldValue = 0
			}
			if gameWeek == 0 {
				newValue = nil
			} else {
				newValue = &gameWeek
			}
			if gameWeek != oldValue {
				fixture.GameWeek = newValue
				updated = append(updated, fixture)
			}
			// fuck i hate pointers sometimes
		}
		if fixture.GameWeek != nil {
			gameWeeks[*fixture.GameWeek]++
		}
	}
	for i := range len(gameWeeks) {
		count, exists := gameWeeks[i+1]
		if !exists || count < 1 {
			return nil, false
		}
	}
	return updated, true
}