package requests

import (
	"encoding/base64"
	"errors"
	"fmt"
	"io"
	"log"
	"net/http"
	"strconv"
	"strings"

	"github.com/frc971/971-Robot-Code/scouting/db"
	"github.com/frc971/971-Robot-Code/scouting/scraping"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/error_response"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/refresh_match_list"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/refresh_match_list_response"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/request_all_matches"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/request_all_matches_response"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/request_data_scouting"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/request_data_scouting_response"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/request_matches_for_team"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/request_matches_for_team_response"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/submit_data_scouting"
	"github.com/frc971/971-Robot-Code/scouting/webserver/requests/messages/submit_data_scouting_response"
	"github.com/frc971/971-Robot-Code/scouting/webserver/server"
	flatbuffers "github.com/google/flatbuffers/go"
)

type SubmitDataScouting = submit_data_scouting.SubmitDataScouting
type SubmitDataScoutingResponseT = submit_data_scouting_response.SubmitDataScoutingResponseT
type RequestAllMatches = request_all_matches.RequestAllMatches
type RequestAllMatchesResponseT = request_all_matches_response.RequestAllMatchesResponseT
type RequestMatchesForTeam = request_matches_for_team.RequestMatchesForTeam
type RequestMatchesForTeamResponseT = request_matches_for_team_response.RequestMatchesForTeamResponseT
type RequestDataScouting = request_data_scouting.RequestDataScouting
type RequestDataScoutingResponseT = request_data_scouting_response.RequestDataScoutingResponseT
type RefreshMatchList = refresh_match_list.RefreshMatchList
type RefreshMatchListResponseT = refresh_match_list_response.RefreshMatchListResponseT

// The interface we expect the database abstraction to conform to.
// We use an interface here because it makes unit testing easier.
type Database interface {
	AddToMatch(db.Match) error
	AddToStats(db.Stats) error
	ReturnMatches() ([]db.Match, error)
	ReturnStats() ([]db.Stats, error)
	QueryMatches(int32) ([]db.Match, error)
	QueryStats(int) ([]db.Stats, error)
}

type ScrapeMatchList func(int32, string) ([]scraping.Match, error)

// Handles unknown requests. Just returns a 404.
func unknown(w http.ResponseWriter, req *http.Request) {
	w.WriteHeader(http.StatusNotFound)
}

func respondWithError(w http.ResponseWriter, statusCode int, errorMessage string) {
	builder := flatbuffers.NewBuilder(1024)
	builder.Finish((&error_response.ErrorResponseT{
		ErrorMessage: errorMessage,
	}).Pack(builder))
	w.WriteHeader(statusCode)
	w.Write(builder.FinishedBytes())
}

func respondNotImplemented(w http.ResponseWriter) {
	respondWithError(w, http.StatusNotImplemented, "")
}

// TODO(phil): Can we turn this into a generic?
func parseSubmitDataScouting(w http.ResponseWriter, buf []byte) (*SubmitDataScouting, bool) {
	success := true
	defer func() {
		if r := recover(); r != nil {
			respondWithError(w, http.StatusBadRequest, fmt.Sprintf("Failed to parse SubmitDataScouting: %v", r))
			success = false
		}
	}()
	result := submit_data_scouting.GetRootAsSubmitDataScouting(buf, 0)
	return result, success
}

// Parses the authorization information that the browser inserts into the
// headers.  The authorization follows this format:
//
//  req.Headers["Authorization"] = []string{"Basic <base64 encoded username:password>"}
func parseUsername(req *http.Request) string {
	auth, ok := req.Header["Authorization"]
	if !ok {
		return "unknown"
	}

	parts := strings.Split(auth[0], " ")
	if !(len(parts) == 2 && parts[0] == "Basic") {
		return "unknown"
	}

	info, err := base64.StdEncoding.DecodeString(parts[1])
	if err != nil {
		log.Println("ERROR: Failed to parse Basic authentication.")
		return "unknown"
	}

	loginParts := strings.Split(string(info), ":")
	if len(loginParts) != 2 {
		return "unknown"
	}
	return loginParts[0]
}

// Handles a SubmitDataScouting request.
type submitDataScoutingHandler struct {
	db Database
}

func (handler submitDataScoutingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	// Get the username of the person submitting the data.
	username := parseUsername(req)
	log.Println("Got data scouting data from", username)

	requestBytes, err := io.ReadAll(req.Body)
	if err != nil {
		respondWithError(w, http.StatusBadRequest, fmt.Sprint("Failed to read request bytes:", err))
		return
	}

	request, success := parseSubmitDataScouting(w, requestBytes)
	if !success {
		return
	}

	stats := db.Stats{
		TeamNumber:      request.Team(),
		MatchNumber:     request.Match(),
		ShotsMissedAuto: request.MissedShotsAuto(),
		UpperGoalAuto:   request.UpperGoalAuto(),
		LowerGoalAuto:   request.LowerGoalAuto(),
		ShotsMissed:     request.MissedShotsTele(),
		UpperGoalShots:  request.UpperGoalTele(),
		LowerGoalShots:  request.LowerGoalTele(),
		PlayedDefense:   request.DefenseRating(),
		Climbing:        request.Climbing(),
		CollectedBy:     username,
	}

	err = handler.db.AddToStats(stats)
	if err != nil {
		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Failed to submit datascouting data: ", err))
	}

	builder := flatbuffers.NewBuilder(50 * 1024)
	builder.Finish((&SubmitDataScoutingResponseT{}).Pack(builder))
	w.Write(builder.FinishedBytes())
}

// TODO(phil): Can we turn this into a generic?
func parseRequestAllMatches(w http.ResponseWriter, buf []byte) (*RequestAllMatches, bool) {
	success := true
	defer func() {
		if r := recover(); r != nil {
			respondWithError(w, http.StatusBadRequest, fmt.Sprintf("Failed to parse SubmitDataScouting: %v", r))
			success = false
		}
	}()
	result := request_all_matches.GetRootAsRequestAllMatches(buf, 0)
	return result, success
}

// Handles a RequestAllMaches request.
type requestAllMatchesHandler struct {
	db Database
}

func (handler requestAllMatchesHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	requestBytes, err := io.ReadAll(req.Body)
	if err != nil {
		respondWithError(w, http.StatusBadRequest, fmt.Sprint("Failed to read request bytes:", err))
		return
	}

	_, success := parseRequestAllMatches(w, requestBytes)
	if !success {
		return
	}

	matches, err := handler.db.ReturnMatches()
	if err != nil {
		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Failed to query database: ", err))
		return
	}

	var response RequestAllMatchesResponseT
	for _, match := range matches {
		response.MatchList = append(response.MatchList, &request_all_matches_response.MatchT{
			MatchNumber: match.MatchNumber,
			Round:       match.Round,
			CompLevel:   match.CompLevel,
			R1:          match.R1,
			R2:          match.R2,
			R3:          match.R3,
			B1:          match.B1,
			B2:          match.B2,
			B3:          match.B3,
		})
	}

	builder := flatbuffers.NewBuilder(50 * 1024)
	builder.Finish((&response).Pack(builder))
	w.Write(builder.FinishedBytes())
}

// TODO(phil): Can we turn this into a generic?
func parseRequestMatchesForTeam(w http.ResponseWriter, buf []byte) (*RequestMatchesForTeam, bool) {
	success := true
	defer func() {
		if r := recover(); r != nil {
			respondWithError(w, http.StatusBadRequest, fmt.Sprintf("Failed to parse SubmitDataScouting: %v", r))
			success = false
		}
	}()
	result := request_matches_for_team.GetRootAsRequestMatchesForTeam(buf, 0)
	return result, success
}

// Handles a RequestMatchesForTeam request.
type requestMatchesForTeamHandler struct {
	db Database
}

func (handler requestMatchesForTeamHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	requestBytes, err := io.ReadAll(req.Body)
	if err != nil {
		respondWithError(w, http.StatusBadRequest, fmt.Sprint("Failed to read request bytes:", err))
		return
	}

	request, success := parseRequestMatchesForTeam(w, requestBytes)
	if !success {
		return
	}

	matches, err := handler.db.QueryMatches(request.Team())
	if err != nil {
		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Faled to query database: ", err))
		return
	}

	var response RequestAllMatchesResponseT
	for _, match := range matches {
		response.MatchList = append(response.MatchList, &request_all_matches_response.MatchT{
			MatchNumber: match.MatchNumber,
			Round:       match.Round,
			CompLevel:   match.CompLevel,
			R1:          match.R1,
			R2:          match.R2,
			R3:          match.R3,
			B1:          match.B1,
			B2:          match.B2,
			B3:          match.B3,
		})
	}

	builder := flatbuffers.NewBuilder(50 * 1024)
	builder.Finish((&response).Pack(builder))
	w.Write(builder.FinishedBytes())
}

// TODO(phil): Can we turn this into a generic?
func parseRequestDataScouting(w http.ResponseWriter, buf []byte) (*RequestDataScouting, bool) {
	success := true
	defer func() {
		if r := recover(); r != nil {
			respondWithError(w, http.StatusBadRequest, fmt.Sprintf("Failed to parse SubmitDataScouting: %v", r))
			success = false
		}
	}()
	result := request_data_scouting.GetRootAsRequestDataScouting(buf, 0)
	return result, success
}

// Handles a RequestDataScouting request.
type requestDataScoutingHandler struct {
	db Database
}

func (handler requestDataScoutingHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	requestBytes, err := io.ReadAll(req.Body)
	if err != nil {
		respondWithError(w, http.StatusBadRequest, fmt.Sprint("Failed to read request bytes:", err))
		return
	}

	_, success := parseRequestDataScouting(w, requestBytes)
	if !success {
		return
	}

	stats, err := handler.db.ReturnStats()
	if err != nil {
		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Faled to query database: ", err))
		return
	}

	var response RequestDataScoutingResponseT
	for _, stat := range stats {
		response.StatsList = append(response.StatsList, &request_data_scouting_response.StatsT{
			Team:            stat.TeamNumber,
			Match:           stat.MatchNumber,
			MissedShotsAuto: stat.ShotsMissedAuto,
			UpperGoalAuto:   stat.UpperGoalAuto,
			LowerGoalAuto:   stat.LowerGoalAuto,
			MissedShotsTele: stat.ShotsMissed,
			UpperGoalTele:   stat.UpperGoalShots,
			LowerGoalTele:   stat.LowerGoalShots,
			DefenseRating:   stat.PlayedDefense,
			Climbing:        stat.Climbing,
			CollectedBy:     stat.CollectedBy,
		})
	}

	builder := flatbuffers.NewBuilder(50 * 1024)
	builder.Finish((&response).Pack(builder))
	w.Write(builder.FinishedBytes())
}

// TODO(phil): Can we turn this into a generic?
func parseRefreshMatchList(w http.ResponseWriter, buf []byte) (*RefreshMatchList, bool) {
	success := true
	defer func() {
		if r := recover(); r != nil {
			respondWithError(w, http.StatusBadRequest, fmt.Sprintf("Failed to parse RefreshMatchList: %v", r))
			success = false
		}
	}()
	result := refresh_match_list.GetRootAsRefreshMatchList(buf, 0)
	return result, success
}

func parseTeamKey(teamKey string) (int, error) {
	// TBA prefixes teams with "frc". Not sure why. Get rid of that.
	teamKey = strings.TrimPrefix(teamKey, "frc")
	return strconv.Atoi(teamKey)
}

// Parses the alliance data from the specified match and returns the three red
// teams and the three blue teams.
func parseTeamKeys(match *scraping.Match) ([3]int32, [3]int32, error) {
	redKeys := match.Alliances.Red.TeamKeys
	blueKeys := match.Alliances.Blue.TeamKeys

	if len(redKeys) != 3 || len(blueKeys) != 3 {
		return [3]int32{}, [3]int32{}, errors.New(fmt.Sprintf(
			"Found %d red teams and %d blue teams.", len(redKeys), len(blueKeys)))
	}

	var red [3]int32
	for i, key := range redKeys {
		team, err := parseTeamKey(key)
		if err != nil {
			return [3]int32{}, [3]int32{}, errors.New(fmt.Sprintf(
				"Failed to parse red %d team '%s' as integer: %v", i+1, key, err))
		}
		red[i] = int32(team)
	}
	var blue [3]int32
	for i, key := range blueKeys {
		team, err := parseTeamKey(key)
		if err != nil {
			return [3]int32{}, [3]int32{}, errors.New(fmt.Sprintf(
				"Failed to parse blue %d team '%s' as integer: %v", i+1, key, err))
		}
		blue[i] = int32(team)
	}
	return red, blue, nil
}

type refreshMatchListHandler struct {
	db     Database
	scrape ScrapeMatchList
}

func (handler refreshMatchListHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	requestBytes, err := io.ReadAll(req.Body)
	if err != nil {
		respondWithError(w, http.StatusBadRequest, fmt.Sprint("Failed to read request bytes:", err))
		return
	}

	request, success := parseRefreshMatchList(w, requestBytes)
	if !success {
		return
	}

	matches, err := handler.scrape(request.Year(), string(request.EventCode()))
	if err != nil {
		respondWithError(w, http.StatusInternalServerError, fmt.Sprint("Faled to scrape match list: ", err))
		return
	}

	for _, match := range matches {
		// Make sure the data is valid.
		red, blue, err := parseTeamKeys(&match)
		if err != nil {
			respondWithError(w, http.StatusInternalServerError, fmt.Sprintf(
				"TheBlueAlliance data for match %d is malformed: %v", match.MatchNumber, err))
			return
		}
		// Add the match to the database.
		err = handler.db.AddToMatch(db.Match{
			MatchNumber: int32(match.MatchNumber),
			// TODO(phil): What does Round mean?
			Round:     1,
			CompLevel: match.CompLevel,
			R1:        red[0],
			R2:        red[1],
			R3:        red[2],
			B1:        blue[0],
			B2:        blue[1],
			B3:        blue[2],
		})
		if err != nil {
			respondWithError(w, http.StatusInternalServerError, fmt.Sprintf(
				"Failed to add match %d to the database: %v", match.MatchNumber, err))
			return
		}
	}

	var response RefreshMatchListResponseT
	builder := flatbuffers.NewBuilder(1024)
	builder.Finish((&response).Pack(builder))
	w.Write(builder.FinishedBytes())
}

func HandleRequests(db Database, scrape ScrapeMatchList, scoutingServer server.ScoutingServer) {
	scoutingServer.HandleFunc("/requests", unknown)
	scoutingServer.Handle("/requests/submit/data_scouting", submitDataScoutingHandler{db})
	scoutingServer.Handle("/requests/request/all_matches", requestAllMatchesHandler{db})
	scoutingServer.Handle("/requests/request/matches_for_team", requestMatchesForTeamHandler{db})
	scoutingServer.Handle("/requests/request/data_scouting", requestDataScoutingHandler{db})
	scoutingServer.Handle("/requests/refresh_match_list", refreshMatchListHandler{db, scrape})
}