package main

import (
        "context"
        "encoding/json"
        "fmt"
        "log"
        "net/http"
        "os"
        "strconv"
        "strings"

        "github.com/jackc/pgx/v5/pgxpool"
)

type CompetitionPostResults struct {
        SplatfestID uint32 `json:"splatfest_id"`
        Score       uint32 `json:"score"`
        TeamID      uint8  `json:"team_id"`
        TeamWin     uint8  `json:"team_win"`
        User        uint32 `json:"user"`
}

var db *pgxpool.Pool

func main() {
        var err error
        connStr := os.Getenv("DATABASE_URL")
        db, err = pgxpool.New(context.Background(), connStr)
        if err != nil {
                log.Fatalf("Unable to connect to database: %v\n", err)
        }
        defer db.Close()

        http.HandleFunc("/results/get", handleGetResults)
        http.HandleFunc("/results/votes", handleGetVotes)
        http.HandleFunc("/results/post", handlePostResults)

        log.Println("Server starting on :8000...")
        log.Fatal(http.ListenAndServe(":8000", nil))
}

// GET /results/get?splatfest_id=<id>
func handleGetResults(w http.ResponseWriter, r *http.Request) {
        festID := r.URL.Query().Get("splatfest_id")

        rows, err := db.Query(context.Background(),
                "SELECT splatfest_id, score, team_id, team_win, user_id FROM results WHERE splatfest_id = $1", festID)
        if err != nil {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
        }
        defer rows.Close()

        var results []CompetitionPostResults
        for rows.Next() {
                var res CompetitionPostResults
                err := rows.Scan(&res.SplatfestID, &res.Score, &res.TeamID, &res.TeamWin, &res.User)
                if err != nil {
                        continue
                }
                results = append(results, res)
        }

        w.Header().Set("Content-Type", "application/json")
        json.NewEncoder(w).Encode(results)
}

// GET /results/votes?splatfest_id=<id>
func handleGetVotes(w http.ResponseWriter, r *http.Request) {
        festID := r.URL.Query().Get("splatfest_id")

        rows, err := db.Query(context.Background(),
                "SELECT team_id, COUNT(user_id) FROM user_votes WHERE splatfest_id = $1 GROUP BY team_id ORDER BY team_id ASC", festID)
        if err != nil {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
        }
        defer rows.Close()

        // genuinely i can't be assed anymore
        voteCounts := make(map[uint8]uint32)
        maxID := 0
        for rows.Next() {
                var tid uint8
                var count uint32
                if err := rows.Scan(&tid, &count); err == nil {
                        voteCounts[tid] = count
                        if int(tid) > maxID {
                                maxID = int(tid)
                        }
                }
        }

        resultArr := make([]string, maxID+1)
        for i := 0; i <= maxID; i++ {
                resultArr[i] = strconv.FormatUint(uint64(voteCounts[uint8(i)]), 10)
        }

        fmt.Fprintf(w, "[%s]", strings.Join(resultArr, ","))
}

// POST /results/post
func handlePostResults(w http.ResponseWriter, r *http.Request) {
        var res CompetitionPostResults
        if err := json.NewDecoder(r.Body).Decode(&res); err != nil {
                http.Error(w, "Invalid JSON", http.StatusBadRequest)
                return
        }

        ctx := context.Background()
        tx, err := db.Begin(ctx)
        if err != nil {
                http.Error(w, "Transaction error", http.StatusInternalServerError)
                return
        }
        defer tx.Rollback(ctx)

        _, err = tx.Exec(ctx,
                "INSERT INTO results (splatfest_id, score, team_id, team_win, user_id) VALUES ($1, $2, $3, $4, $5)",
                res.SplatfestID, res.Score, res.TeamID, res.TeamWin, res.User)
        if err != nil {
                log.Printf("DB Error results: %v", err)
                return
        }

        _, err = tx.Exec(ctx,
                "INSERT INTO user_votes (user_id, splatfest_id, team_id) VALUES ($1, $2, $3) ON CONFLICT DO NOTHING",
                res.User, res.SplatfestID, res.TeamID)
        if err != nil {
                log.Printf("DB Error votes: %v", err)
                return
        }

        tx.Commit(ctx)
        w.WriteHeader(http.StatusOK)
}