package game

import (
    "errors"
    "fmt"
    "localrepo/plugins/structs"
)

// TicTacToeRules implements GameRules for 3x3 Tic Tac Toe.
type TicTacToeRules struct{}

// -------------------------------
// GameRules Implementation
// -------------------------------

func (t *TicTacToeRules) MaxPlayers() int {
    return 2
}

// Assign player symbols: X and O
func (t *TicTacToeRules) AssignPlayerSymbols(players []*Player) {
    if len(players) < 2 {
        return
    }

    players[0].Metadata["symbol"] = "X"
    players[1].Metadata["symbol"] = "O"
}

// ValidateMove checks bounds and empty cell.
func (t *TicTacToeRules) ValidateMove(state *structs.MatchState, playerIdx int, payload MovePayload) bool {

    rowVal, ok1 := payload.Data["row"]
    colVal, ok2 := payload.Data["col"]

    if !ok1 || !ok2 {
        return false
    }

    row, ok3 := rowVal.(float64)
    col, ok4 := colVal.(float64)

    if !ok3 || !ok4 {
        return false
    }

    r := int(row)
    c := int(col)

    // bounds
    if !state.Board.InBounds(r, c) {
        return false
    }

    // empty?
    return state.Board.IsEmpty(r, c)
}

// ApplyMove writes X or O to the board.
func (t *TicTacToeRules) ApplyMove(state *structs.MatchState, playerIdx int, payload MovePayload) {

    symbol := state.Players[playerIdx].Metadata["symbol"]

    r := int(payload.Data["row"].(float64))
    c := int(payload.Data["col"].(float64))

    state.Board.Set(r, c, symbol)
}

// CheckGameOver determines win/draw state.
func (t *TicTacToeRules) CheckGameOver(state *structs.MatchState) (bool, int) {

    winnerSymbol := t.findWinner(state.Board)

    if winnerSymbol != "" {
        // find the player with this symbol
        for _, p := range state.Players {
            if p.Metadata["symbol"] == winnerSymbol {
                return true, p.Index
            }
        }
        return true, -1
    }

    if state.Board.Full() {
        return true, -1 // draw
    }

    return false, -1
}

// OnForfeit: whoever leaves loses instantly
func (t *TicTacToeRules) ForfeitWinner(state *structs.MatchState, leaverIndex int) int {

    // If player 0 leaves, player 1 wins.
    if leaverIndex == 0 && len(state.Players) > 1 {
        return 1
    }

    // If player 1 leaves, player 0 wins.
    if leaverIndex == 1 && len(state.Players) > 0 {
        return 0
    }

    // Otherwise draw.
    return -1
}

// -------------------------------
// Helper: winner detection
// -------------------------------

func (t *TicTacToeRules) findWinner(b *structs.Board) string {

    lines := [][][2]int{
        // rows
        {{0, 0}, {0, 1}, {0, 2}},
        {{1, 0}, {1, 1}, {1, 2}},
        {{2, 0}, {2, 1}, {2, 2}},
        // cols
        {{0, 0}, {1, 0}, {2, 0}},
        {{0, 1}, {1, 1}, {2, 1}},
        {{0, 2}, {1, 2}, {2, 2}},
        // diagonals
        {{0, 0}, {1, 1}, {2, 2}},
        {{0, 2}, {1, 1}, {2, 0}},
    }

    for _, line := range lines {
        r1, c1 := line[0][0], line[0][1]
        r2, c2 := line[1][0], line[1][1]
        r3, c3 := line[2][0], line[2][1]

        v1 := b.Get(r1, c1)
        if v1 != "" &&
            v1 == b.Get(r2, c2) &&
            v1 == b.Get(r3, c3) {
            return v1
        }
    }

    return ""
}