package server

import (
	"net/http"

	"github.com/gin-gonic/gin"

	"scrabble/backend/internal/engine"
)

// The /api/v1/user/* endpoints require X-User-ID (RequireUserID middleware). The
// backend treats that header as the sole identity input.

// handleProfile returns the authenticated account's own profile.
func (s *Server) handleProfile(c *gin.Context) {
	uid, ok := userID(c)
	if !ok {
		abortBadRequest(c, "missing identity")
		return
	}
	acc, err := s.accounts.GetByID(c.Request.Context(), uid)
	if err != nil {
		s.abortErr(c, err)
		return
	}
	c.JSON(http.StatusOK, profileResponseFor(acc))
}

// submitPlayRequest places tiles in a direction on the player's turn. Each tile's Letter
// is a wire alphabet index (Stage 13); for a blank it is the designated letter's index.
type submitPlayRequest struct {
	Dir   string `json:"dir"`
	Tiles []struct {
		Row    int  `json:"row"`
		Col    int  `json:"col"`
		Letter int  `json:"letter"`
		Blank  bool `json:"blank"`
	} `json:"tiles"`
}

// tilesFromRequest maps a play/evaluate request's index-addressed tiles to engine tile
// records for the game's variant (Stage 13: a placed blank carries its designated letter's
// index with Blank set). An out-of-range index surfaces as engine.ErrIllegalPlay (HTTP 400).
func tilesFromRequest(variant engine.Variant, req submitPlayRequest) ([]engine.TileRecord, error) {
	tiles := make([]engine.TileRecord, 0, len(req.Tiles))
	for _, t := range req.Tiles {
		letter, err := engine.LetterForIndex(variant, t.Letter)
		if err != nil {
			return nil, err
		}
		tiles = append(tiles, engine.TileRecord{Row: t.Row, Col: t.Col, Letter: letter, Blank: t.Blank})
	}
	return tiles, nil
}

// handleSubmitPlay validates, scores and commits a placement.
func (s *Server) handleSubmitPlay(c *gin.Context) {
	uid, ok := userID(c)
	if !ok {
		abortBadRequest(c, "missing identity")
		return
	}
	gameID, ok := gameIDParam(c)
	if !ok {
		abortBadRequest(c, "invalid game id")
		return
	}
	var req submitPlayRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		abortBadRequest(c, "invalid request body")
		return
	}
	dir, ok := parseDirection(req.Dir)
	if !ok {
		abortBadRequest(c, "dir must be H or V")
		return
	}
	variant, err := s.games.GameVariant(c.Request.Context(), gameID)
	if err != nil {
		s.abortErr(c, err)
		return
	}
	tiles, err := tilesFromRequest(variant, req)
	if err != nil {
		s.abortErr(c, err)
		return
	}
	res, err := s.games.SubmitPlay(c.Request.Context(), gameID, uid, dir, tiles)
	if err != nil {
		s.abortErr(c, err)
		return
	}
	s.writeMoveResult(c, res)
}

// handleGameState returns the player's view of a game.
func (s *Server) handleGameState(c *gin.Context) {
	uid, ok := userID(c)
	if !ok {
		abortBadRequest(c, "missing identity")
		return
	}
	gameID, ok := gameIDParam(c)
	if !ok {
		abortBadRequest(c, "invalid game id")
		return
	}
	view, err := s.games.GameState(c.Request.Context(), gameID, uid)
	if err != nil {
		s.abortErr(c, err)
		return
	}
	dto, err := stateDTOFrom(view, c.Query("include_alphabet") == "true")
	if err != nil {
		s.abortErr(c, err)
		return
	}
	s.fillSeatNames(c.Request.Context(), &dto.Game, map[string]string{})
	c.JSON(http.StatusOK, dto)
}

// enqueueRequest joins the per-variant auto-match pool.
type enqueueRequest struct {
	Variant string `json:"variant"`
}

// handleEnqueue joins the auto-match pool for a variant.
func (s *Server) handleEnqueue(c *gin.Context) {
	uid, ok := userID(c)
	if !ok {
		abortBadRequest(c, "missing identity")
		return
	}
	var req enqueueRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		abortBadRequest(c, "invalid request body")
		return
	}
	variant, err := engine.ParseVariant(req.Variant)
	if err != nil {
		abortBadRequest(c, "unknown variant")
		return
	}
	res, err := s.matchmaker.Enqueue(c.Request.Context(), uid, variant)
	if err != nil {
		s.abortErr(c, err)
		return
	}
	dto := matchDTOFrom(res)
	if dto.Game != nil {
		s.fillSeatNames(c.Request.Context(), dto.Game, map[string]string{})
	}
	c.JSON(http.StatusOK, dto)
}

// handleCancel removes the caller from the auto-match pool (and drops any pending
// matched result), so a cancelled quick-match neither blocks a re-queue nor later
// surfaces a robot-substituted game the player abandoned. It is idempotent: cancelling
// when not queued is a no-op success.
func (s *Server) handleCancel(c *gin.Context) {
	uid, ok := userID(c)
	if !ok {
		abortBadRequest(c, "missing identity")
		return
	}
	s.matchmaker.Cancel(c.Request.Context(), uid)
	c.Status(http.StatusNoContent)
}

// handlePoll reports whether the caller has been paired since queueing.
func (s *Server) handlePoll(c *gin.Context) {
	uid, ok := userID(c)
	if !ok {
		abortBadRequest(c, "missing identity")
		return
	}
	res, err := s.matchmaker.Poll(c.Request.Context(), uid)
	if err != nil {
		s.abortErr(c, err)
		return
	}
	dto := matchDTOFrom(res)
	if dto.Game != nil {
		s.fillSeatNames(c.Request.Context(), dto.Game, map[string]string{})
	}
	c.JSON(http.StatusOK, dto)
}

// chatPostRequest posts a per-game chat message.
type chatPostRequest struct {
	Body string `json:"body"`
}

// handleChatPost stores a chat message from the authenticated player. The sender
// IP is taken from the gateway-forwarded X-Forwarded-For header.
func (s *Server) handleChatPost(c *gin.Context) {
	uid, ok := userID(c)
	if !ok {
		abortBadRequest(c, "missing identity")
		return
	}
	gameID, ok := gameIDParam(c)
	if !ok {
		abortBadRequest(c, "invalid game id")
		return
	}
	var req chatPostRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		abortBadRequest(c, "invalid request body")
		return
	}
	msg, err := s.social.PostMessage(c.Request.Context(), gameID, uid, req.Body, clientIP(c))
	if err != nil {
		s.abortErr(c, err)
		return
	}
	c.JSON(http.StatusOK, chatDTOFrom(msg))
}