package handlers

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

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

// FreeAgentsListPage renders the free agents tab of a season league page
func FreeAgentsListPage(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		seasonStr := r.PathValue("season_short_name")
		leagueStr := r.PathValue("league_short_name")

		var season *db.Season
		var league *db.League
		var freeAgents []*db.SeasonLeagueFreeAgent
		var availablePlayers []*db.Player

		if ok := conn.WithReadTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			var err error
			sl, err := db.GetSeasonLeague(ctx, tx, seasonStr, leagueStr)
			if err != nil {
				if db.IsBadRequest(err) {
					throw.NotFound(s, w, r, r.URL.Path)
					return false, nil
				}
				return false, errors.Wrap(err, "db.GetSeasonLeague")
			}
			season = sl.Season
			league = sl.League

			freeAgents, err = db.GetFreeAgentsForSeasonLeague(ctx, tx, season.ID, league.ID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetFreeAgentsForSeasonLeague")
			}

			availablePlayers, err = db.GetPlayersNotOnTeam(ctx, tx, season.ID, league.ID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetPlayersNotOnTeam")
			}

			// Filter out players already registered as free agents
			faMap := make(map[int]bool, len(freeAgents))
			for _, fa := range freeAgents {
				faMap[fa.PlayerID] = true
			}
			filtered := make([]*db.Player, 0, len(availablePlayers))
			for _, p := range availablePlayers {
				if !faMap[p.ID] {
					filtered = append(filtered, p)
				}
			}
			availablePlayers = filtered

			return true, nil
		}); !ok {
			return
		}

		if r.Method == "GET" {
			renderSafely(seasonsview.SeasonLeagueFreeAgentsPage(season, league, freeAgents, availablePlayers), s, r, w)
		} else {
			renderSafely(seasonsview.SeasonLeagueFreeAgents(season, league, freeAgents, availablePlayers), s, r, w)
		}
	})
}

// RegisterFreeAgent handles POST to register a player as a free agent
func RegisterFreeAgent(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		seasonStr := r.PathValue("season_short_name")
		leagueStr := r.PathValue("league_short_name")

		getter, ok := validation.ParseFormOrNotify(s, w, r)
		if !ok {
			respond.BadRequest(w, errors.New("failed to parse form"))
			return
		}

		playerID := getter.Int("player_id").Required().Value
		if !getter.ValidateAndNotify(s, w, r) {
			respond.BadRequest(w, errors.New("invalid form data"))
			return
		}

		if ok := conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			sl, err := db.GetSeasonLeague(ctx, tx, seasonStr, leagueStr)
			if err != nil {
				if db.IsBadRequest(err) {
					throw.NotFound(s, w, r, r.URL.Path)
					return false, nil
				}
				return false, errors.Wrap(err, "db.GetSeasonLeague")
			}

			// Verify player is not on a team in this season_league
			players, err := db.GetPlayersNotOnTeam(ctx, tx, sl.Season.ID, sl.League.ID)
			if err != nil {
				return false, errors.Wrap(err, "db.GetPlayersNotOnTeam")
			}
			playerFound := false
			for _, p := range players {
				if p.ID == playerID {
					playerFound = true
					break
				}
			}
			if !playerFound {
				notify.Warn(s, w, r, "Cannot Register", "Player is already on a team in this league.", nil)
				return false, nil
			}

			// Check if already registered
			isRegistered, err := db.IsFreeAgentRegistered(ctx, tx, sl.Season.ID, sl.League.ID, playerID)
			if err != nil {
				return false, errors.Wrap(err, "db.IsFreeAgentRegistered")
			}
			if isRegistered {
				notify.Warn(s, w, r, "Already Registered", "Player is already registered as a free agent.", nil)
				return false, nil
			}

			err = db.RegisterFreeAgent(ctx, tx, sl.Season.ID, sl.League.ID, playerID, db.NewAuditFromRequest(r))
			if err != nil {
				return false, errors.Wrap(err, "db.RegisterFreeAgent")
			}

			return true, nil
		}); !ok {
			return
		}

		notify.Success(s, w, r, "Free Agent Registered", "Player has been registered as a free agent.", nil)
		respond.HXRedirect(w, "/seasons/%s/leagues/%s/free-agents", seasonStr, leagueStr)
	})
}

// UnregisterFreeAgent handles POST to unregister a player as a free agent
func UnregisterFreeAgent(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		seasonStr := r.PathValue("season_short_name")
		leagueStr := r.PathValue("league_short_name")

		getter, ok := validation.ParseFormOrNotify(s, w, r)
		if !ok {
			respond.BadRequest(w, errors.New("failed to parse form"))
			return
		}

		playerID := getter.Int("player_id").Required().Value
		if !getter.ValidateAndNotify(s, w, r) {
			respond.BadRequest(w, errors.New("invalid form data"))
			return
		}

		if ok := conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			sl, err := db.GetSeasonLeague(ctx, tx, seasonStr, leagueStr)
			if err != nil {
				if db.IsBadRequest(err) {
					throw.NotFound(s, w, r, r.URL.Path)
					return false, nil
				}
				return false, errors.Wrap(err, "db.GetSeasonLeague")
			}

			err = db.UnregisterFreeAgent(ctx, tx, sl.Season.ID, sl.League.ID, playerID, db.NewAuditFromRequest(r))
			if err != nil {
				return false, errors.Wrap(err, "db.UnregisterFreeAgent")
			}

			return true, nil
		}); !ok {
			return
		}

		notify.Success(s, w, r, "Free Agent Removed", "Player has been unregistered as a free agent.", nil)
		respond.HXRedirect(w, "/seasons/%s/leagues/%s/free-agents", seasonStr, leagueStr)
	})
}

// NominateFreeAgentHandler handles POST to nominate a free agent for a fixture
func NominateFreeAgentHandler(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fixtureID, err := strconv.Atoi(r.PathValue("fixture_id"))
		if err != nil {
			throw.BadRequest(s, w, r, "Invalid fixture ID", err)
			return
		}

		getter, ok := validation.ParseFormOrNotify(s, w, r)
		if !ok {
			return
		}

		playerID := getter.Int("player_id").Required().Value
		teamID := getter.Int("team_id").Required().Value
		if !getter.ValidateAndNotify(s, w, r) {
			return
		}

		if ok := conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			// Verify fixture exists and user is a manager
			fixture, err := db.GetFixture(ctx, tx, fixtureID)
			if err != nil {
				if db.IsBadRequest(err) {
					respond.NotFound(w, errors.Wrap(err, "db.GetFixture"))
					return false, nil
				}
				return false, errors.Wrap(err, "db.GetFixture")
			}

			// Check if user can nominate: either a manager of the nominating team,
			// or has fixtures.manage permission (can nominate for either team)
			user := db.CurrentUser(ctx)
			canManage := contexts.Permissions(ctx).HasPermission(permissions.FixturesManage)
			if !canManage {
				canSchedule, userTeamID, err := fixture.CanSchedule(ctx, tx, user)
				if err != nil {
					return false, errors.Wrap(err, "fixture.CanSchedule")
				}
				if !canSchedule || userTeamID != teamID {
					throw.Forbidden(s, w, r, "You must be a manager of the nominating team", nil)
					return false, nil
				}
			}
			// Verify the team_id is actually one of the fixture's teams
			if teamID != fixture.HomeTeamID && teamID != fixture.AwayTeamID {
				throw.BadRequest(s, w, r, "Invalid team for this fixture", nil)
				return false, nil
			}

			// Verify player is a registered free agent in this season_league
			isRegistered, err := db.IsFreeAgentRegistered(ctx, tx, fixture.SeasonID, fixture.LeagueID, playerID)
			if err != nil {
				return false, errors.Wrap(err, "db.IsFreeAgentRegistered")
			}
			if !isRegistered {
				notify.Warn(s, w, r, "Not Registered", "Player is not a registered free agent in this league.", nil)
				return false, nil
			}

			err = db.NominateFreeAgent(ctx, tx, fixtureID, playerID, teamID, db.NewAuditFromRequest(r))
			if err != nil {
				if db.IsBadRequest(err) {
					notify.Warn(s, w, r, "Cannot Nominate", err.Error(), nil)
					return false, nil
				}
				return false, errors.Wrap(err, "db.NominateFreeAgent")
			}

			return true, nil
		}); !ok {
			return
		}

		notify.Success(s, w, r, "Free Agent Nominated", "Free agent has been nominated for this fixture.", nil)
		respond.HXRedirect(w, "/fixtures/%d", fixtureID)
	})
}

// RemoveFreeAgentNominationHandler handles POST to remove a free agent nomination
func RemoveFreeAgentNominationHandler(
	s *hws.Server,
	conn *db.DB,
) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fixtureID, err := strconv.Atoi(r.PathValue("fixture_id"))
		if err != nil {
			throw.BadRequest(s, w, r, "Invalid fixture ID", err)
			return
		}

		playerID, err := strconv.Atoi(r.PathValue("player_id"))
		if err != nil {
			throw.BadRequest(s, w, r, "Invalid player ID", err)
			return
		}

		if ok := conn.WithNotifyTx(s, w, r, func(ctx context.Context, tx bun.Tx) (bool, error) {
			// Check if user can remove: either has fixtures.manage permission,
			// or is a manager of the team that nominated the free agent
			canManage := contexts.Permissions(ctx).HasPermission(permissions.FixturesManage)
			if !canManage {
				fixture, err := db.GetFixture(ctx, tx, fixtureID)
				if err != nil {
					if db.IsBadRequest(err) {
						respond.NotFound(w, errors.Wrap(err, "db.GetFixture"))
						return false, nil
					}
					return false, errors.Wrap(err, "db.GetFixture")
				}
				user := db.CurrentUser(ctx)
				canSchedule, userTeamID, err := fixture.CanSchedule(ctx, tx, user)
				if err != nil {
					return false, errors.Wrap(err, "fixture.CanSchedule")
				}
				if !canSchedule {
					throw.Forbidden(s, w, r, "You must be a team manager to remove nominations", nil)
					return false, nil
				}
				// Verify the nomination belongs to the user's team
				nominations, err := db.GetNominatedFreeAgentsByTeam(ctx, tx, fixtureID, userTeamID)
				if err != nil {
					return false, errors.Wrap(err, "db.GetNominatedFreeAgentsByTeam")
				}
				found := false
				for _, n := range nominations {
					if n.PlayerID == playerID {
						found = true
						break
					}
				}
				if !found {
					throw.Forbidden(s, w, r, "You can only remove nominations made by your team", nil)
					return false, nil
				}
			}

			err := db.RemoveFreeAgentNomination(ctx, tx, fixtureID, playerID, db.NewAuditFromRequest(r))
			if err != nil {
				return false, errors.Wrap(err, "db.RemoveFreeAgentNomination")
			}
			return true, nil
		}); !ok {
			return
		}

		notify.Success(s, w, r, "Nomination Removed", "Free agent nomination has been removed.", nil)
		respond.HXRedirect(w, "/fixtures/%d", fixtureID)
	})
}