package server

import (
	"net/http"
	"strconv"

	"music-server/internal/backend"
	"music-server/internal/logging"

	"github.com/labstack/echo/v5"
	"go.uber.org/zap"
)

// StatisticsHandler handles statistics-related HTTP requests
type StatisticsHandler struct {
	statsBackend *backend.StatisticsHandler
}

// NewStatisticsHandler creates a new StatisticsHandler
func NewStatisticsHandler() *StatisticsHandler {
	return &StatisticsHandler{
		statsBackend: backend.NewStatisticsHandler(),
	}
}

// GetMostPlayedGames returns top N most played games with songs
// GET /api/v1/statistics/games/most-played
//
//	@Summary		Get most played games
//	@Description	Returns the top N most played games with their songs
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Param			limit	query	int	false	"Number of results (default: 10)"
//	@Success		200	{array}	backend.GameWithSongs
//	@Failure		400	{object}	map[string]string
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/games/most-played [get]
func (h *StatisticsHandler) GetMostPlayedGames(ctx *echo.Context) error {
	limit := 10 // default
	limitStr := ctx.QueryParam("limit")
	if limitStr != "" {
		var err error
		limit, err = strconv.Atoi(limitStr)
		if err != nil || limit <= 0 {
			return ctx.JSON(http.StatusBadRequest, map[string]string{"error": "Invalid limit parameter"})
		}
		// Cap at 100 for performance
		if limit > 100 {
			limit = 100
		}
	}
	
	games, err := h.statsBackend.GetMostPlayedGamesWithSongs(int32(limit))
	if err != nil {
		logging.GetLogger().Error("Failed to get most played games", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, games)
}

// GetLeastPlayedGames returns top N least played games with songs
// GET /api/v1/statistics/games/least-played
//
//	@Summary		Get least played games
//	@Description	Returns the top N least played games with their songs
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Param			limit	query	int	false	"Number of results (default: 10)"
//	@Success		200	{array}	backend.GameWithSongs
//	@Failure		400	{object}	map[string]string
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/games/least-played [get]
func (h *StatisticsHandler) GetLeastPlayedGames(ctx *echo.Context) error {
	limit := 10
	limitStr := ctx.QueryParam("limit")
	if limitStr != "" {
		var err error
		limit, err = strconv.Atoi(limitStr)
		if err != nil || limit <= 0 {
			return ctx.JSON(http.StatusBadRequest, map[string]string{"error": "Invalid limit parameter"})
		}
		if limit > 100 {
			limit = 100
		}
	}
	
	games, err := h.statsBackend.GetLeastPlayedGamesWithSongs(int32(limit))
	if err != nil {
		logging.GetLogger().Error("Failed to get least played games", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, games)
}

// GetMostPlayedSongs returns top N most played songs with game info
// GET /api/v1/statistics/songs/most-played
//
//	@Summary		Get most played songs
//	@Description	Returns the top N most played songs with their game info
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Param			limit	query	int	false	"Number of results (default: 10)"
//	@Success		200	{array}	backend.SongInfoForStats
//	@Failure		400	{object}	map[string]string
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/songs/most-played [get]
func (h *StatisticsHandler) GetMostPlayedSongs(ctx *echo.Context) error {
	limit := 10
	limitStr := ctx.QueryParam("limit")
	if limitStr != "" {
		var err error
		limit, err = strconv.Atoi(limitStr)
		if err != nil || limit <= 0 {
			return ctx.JSON(http.StatusBadRequest, map[string]string{"error": "Invalid limit parameter"})
		}
		if limit > 100 {
			limit = 100
		}
	}
	
	songs, err := h.statsBackend.GetMostPlayedSongsWithGame(int32(limit))
	if err != nil {
		logging.GetLogger().Error("Failed to get most played songs", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, songs)
}

// GetLeastPlayedSongs returns top N least played songs with game info
// GET /api/v1/statistics/songs/least-played
//
//	@Summary		Get least played songs
//	@Description	Returns the top N least played songs with their game info
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Param			limit	query	int	false	"Number of results (default: 10)"
//	@Success		200	{array}	backend.SongInfoForStats
//	@Failure		400	{object}	map[string]string
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/songs/least-played [get]
func (h *StatisticsHandler) GetLeastPlayedSongs(ctx *echo.Context) error {
	limit := 10
	limitStr := ctx.QueryParam("limit")
	if limitStr != "" {
		var err error
		limit, err = strconv.Atoi(limitStr)
		if err != nil || limit <= 0 {
			return ctx.JSON(http.StatusBadRequest, map[string]string{"error": "Invalid limit parameter"})
		}
		if limit > 100 {
			limit = 100
		}
	}
	
	songs, err := h.statsBackend.GetLeastPlayedSongsWithGame(int32(limit))
	if err != nil {
		logging.GetLogger().Error("Failed to get least played songs", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, songs)
}

// GetNeverPlayedGames returns games that have never been played
// GET /api/v1/statistics/games/never-played
//
//	@Summary		Get never played games
//	@Description	Returns all games that have never been played (times_played = 0)
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Success		200	{array}	backend.GameWithSongs
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/games/never-played [get]
func (h *StatisticsHandler) GetNeverPlayedGames(ctx *echo.Context) error {
	games, err := h.statsBackend.GetNeverPlayedGames()
	if err != nil {
		logging.GetLogger().Error("Failed to get never played games", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, games)
}

// GetLastPlayedGames returns most recently played games
// GET /api/v1/statistics/games/last-played
//
//	@Summary		Get last played games
//	@Description	Returns the most recently played games
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Param			limit	query	int	false	"Number of results (default: 10)"
//	@Success		200	{array}	backend.GameWithSongs
//	@Failure		400	{object}	map[string]string
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/games/last-played [get]
func (h *StatisticsHandler) GetLastPlayedGames(ctx *echo.Context) error {
	limit := 10
	limitStr := ctx.QueryParam("limit")
	if limitStr != "" {
		var err error
		limit, err = strconv.Atoi(limitStr)
		if err != nil || limit <= 0 {
			return ctx.JSON(http.StatusBadRequest, map[string]string{"error": "Invalid limit parameter"})
		}
		if limit > 100 {
			limit = 100
		}
	}
	
	games, err := h.statsBackend.GetLastPlayedGames(int32(limit))
	if err != nil {
		logging.GetLogger().Error("Failed to get last played games", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, games)
}

// GetOldestPlayedGames returns least recently played games
// GET /api/v1/statistics/games/oldest-played
//
//	@Summary		Get oldest played games
//	@Description	Returns the least recently played games (that have been played at least once)
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Param			limit	query	int	false	"Number of results (default: 10)"
//	@Success		200	{array}	backend.GameWithSongs
//	@Failure		400	{object}	map[string]string
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/games/oldest-played [get]
func (h *StatisticsHandler) GetOldestPlayedGames(ctx *echo.Context) error {
	limit := 10
	limitStr := ctx.QueryParam("limit")
	if limitStr != "" {
		var err error
		limit, err = strconv.Atoi(limitStr)
		if err != nil || limit <= 0 {
			return ctx.JSON(http.StatusBadRequest, map[string]string{"error": "Invalid limit parameter"})
		}
		if limit > 100 {
			limit = 100
		}
	}
	
	games, err := h.statsBackend.GetOldestPlayedGames(int32(limit))
	if err != nil {
		logging.GetLogger().Error("Failed to get oldest played games", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, games)
}

// GetStatisticsSummary returns overall statistics
// GET /api/v1/statistics/summary
//
//	@Summary		Get statistics summary
//	@Description	Returns overall statistics about the music library
//	@Tags			statistics
//	@Accept		json
//	@Produce		json
//	@Success		200	{object}	backend.StatisticsSummary
//	@Failure		500	{object}	map[string]string
//	@Router		/api/v1/statistics/summary [get]
func (h *StatisticsHandler) GetStatisticsSummary(ctx *echo.Context) error {
	summary, err := h.statsBackend.GetStatisticsSummary()
	if err != nil {
		logging.GetLogger().Error("Failed to get statistics summary", zap.String("error", err.Error()))
		return ctx.JSON(http.StatusInternalServerError, map[string]string{"error": "Failed to get statistics"})
	}
	return ctx.JSON(http.StatusOK, summary)
}