package handler

import (
	"errors"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"

	"nex/backend/internal/config"
	appErrors "nex/backend/pkg/errors"
)

type SettingsHandler struct {
	runtimeCfg *config.Config
	mode       string
	editable   bool
	configPath string
}

func NewSettingsHandler(runtimeCfg *config.Config, mode string, editable bool, configPath string) *SettingsHandler {
	return &SettingsHandler{
		runtimeCfg: runtimeCfg,
		mode:       mode,
		editable:   editable,
		configPath: configPath,
	}
}

type serverConfigDTO struct {
	Port         int    `json:"port"`
	ReadTimeout  string `json:"read_timeout"`
	WriteTimeout string `json:"write_timeout"`
}

type databaseConfigDTO struct {
	Driver          string `json:"driver"`
	Path            string `json:"path"`
	Host            string `json:"host"`
	Port            int    `json:"port"`
	User            string `json:"user"`
	Password        string `json:"password"`
	DBName          string `json:"dbname"`
	MaxIdleConns    int    `json:"max_idle_conns"`
	MaxOpenConns    int    `json:"max_open_conns"`
	ConnMaxLifetime string `json:"conn_max_lifetime"`
}

type logConfigDTO struct {
	Level      string `json:"level"`
	Path       string `json:"path"`
	MaxSize    int    `json:"max_size"`
	MaxBackups int    `json:"max_backups"`
	MaxAge     int    `json:"max_age"`
	Compress   bool   `json:"compress"`
}

type startupSettingsDTO struct {
	Server   serverConfigDTO   `json:"server"`
	Database databaseConfigDTO `json:"database"`
	Log      logConfigDTO      `json:"log"`
}

type startupSettingsResponse struct {
	Mode            string             `json:"mode"`
	Editable        bool               `json:"editable"`
	ConfigPath      string             `json:"config_path"`
	RestartRequired bool               `json:"restart_required"`
	Config          startupSettingsDTO `json:"config"`
}

func configToDTO(cfg *config.Config) startupSettingsDTO {
	return startupSettingsDTO{
		Server: serverConfigDTO{
			Port:         cfg.Server.Port,
			ReadTimeout:  cfg.Server.ReadTimeout.String(),
			WriteTimeout: cfg.Server.WriteTimeout.String(),
		},
		Database: databaseConfigDTO{
			Driver:          cfg.Database.Driver,
			Path:            cfg.Database.Path,
			Host:            cfg.Database.Host,
			Port:            cfg.Database.Port,
			User:            cfg.Database.User,
			Password:        cfg.Database.Password,
			DBName:          cfg.Database.DBName,
			MaxIdleConns:    cfg.Database.MaxIdleConns,
			MaxOpenConns:    cfg.Database.MaxOpenConns,
			ConnMaxLifetime: cfg.Database.ConnMaxLifetime.String(),
		},
		Log: logConfigDTO{
			Level:      cfg.Log.Level,
			Path:       cfg.Log.Path,
			MaxSize:    cfg.Log.MaxSize,
			MaxBackups: cfg.Log.MaxBackups,
			MaxAge:     cfg.Log.MaxAge,
			Compress:   cfg.Log.Compress,
		},
	}
}

func dtoToConfig(dto startupSettingsDTO) (*config.Config, error) {
	readTimeout, err := time.ParseDuration(dto.Server.ReadTimeout)
	if err != nil {
		return nil, appErrors.WithMessage(appErrors.ErrInvalidRequest, "read_timeout 格式错误，例如 30s")
	}
	writeTimeout, err := time.ParseDuration(dto.Server.WriteTimeout)
	if err != nil {
		return nil, appErrors.WithMessage(appErrors.ErrInvalidRequest, "write_timeout 格式错误，例如 30s")
	}
	connMaxLifetime, err := time.ParseDuration(dto.Database.ConnMaxLifetime)
	if err != nil {
		return nil, appErrors.WithMessage(appErrors.ErrInvalidRequest, "conn_max_lifetime 格式错误，例如 1h")
	}

	return &config.Config{
		Server: config.ServerConfig{
			Port:         dto.Server.Port,
			ReadTimeout:  readTimeout,
			WriteTimeout: writeTimeout,
		},
		Database: config.DatabaseConfig{
			Driver:          dto.Database.Driver,
			Path:            dto.Database.Path,
			Host:            dto.Database.Host,
			Port:            dto.Database.Port,
			User:            dto.Database.User,
			Password:        dto.Database.Password,
			DBName:          dto.Database.DBName,
			MaxIdleConns:    dto.Database.MaxIdleConns,
			MaxOpenConns:    dto.Database.MaxOpenConns,
			ConnMaxLifetime: connMaxLifetime,
		},
		Log: config.LogConfig{
			Level:      dto.Log.Level,
			Path:       dto.Log.Path,
			MaxSize:    dto.Log.MaxSize,
			MaxBackups: dto.Log.MaxBackups,
			MaxAge:     dto.Log.MaxAge,
			Compress:   dto.Log.Compress,
		},
	}, nil
}

func (h *SettingsHandler) GetStartupSettings(c *gin.Context) {
	var cfg *config.Config
	var configPath string

	if h.mode == "desktop" {
		desktopCfg, err := config.LoadDesktopConfigAtPath(h.configPath)
		if err != nil {
			writeError(c, err)
			return
		}
		cfg = desktopCfg
		configPath = h.configPath
	} else {
		cfg = h.runtimeCfg
		configPath = h.configPath
	}

	c.JSON(http.StatusOK, startupSettingsResponse{
		Mode:            h.mode,
		Editable:        h.editable,
		ConfigPath:      configPath,
		RestartRequired: h.editable,
		Config:          configToDTO(cfg),
	})
}

func (h *SettingsHandler) SaveStartupSettings(c *gin.Context) {
	if !h.editable {
		c.JSON(http.StatusForbidden, gin.H{
			"error": "server 模式下不允许保存启动参数",
			"code":  "forbidden",
		})
		return
	}

	var req struct {
		Config startupSettingsDTO `json:"config"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{
			"error": "无效的请求格式",
		})
		return
	}

	cfg, err := dtoToConfig(req.Config)
	if err != nil {
		writeError(c, err)
		return
	}

	if err := cfg.Validate(); err != nil {
		writeError(c, err)
		return
	}

	if err := config.SaveConfigToPath(cfg, h.configPath); err != nil {
		if errors.Is(err, appErrors.ErrInvalidRequest) {
			writeError(c, err)
			return
		}
		writeError(c, appErrors.Wrap(appErrors.ErrInternal, err))
		return
	}

	savedCfg, err := config.LoadDesktopConfigAtPath(h.configPath)
	if err != nil {
		writeError(c, appErrors.Wrap(appErrors.ErrInternal, err))
		return
	}

	c.JSON(http.StatusOK, startupSettingsResponse{
		Mode:            h.mode,
		Editable:        h.editable,
		ConfigPath:      h.configPath,
		RestartRequired: true,
		Config:          configToDTO(savedCfg),
	})
}