package main

import (
    "fmt"
    "net/http"
    "strconv"

    "github.com/jinzhu/gorm"
    _ "github.com/jinzhu/gorm/dialects/sqlite"
    "github.com/labstack/echo"
)

type User struct {
    gorm.Model `json:"model"`
    Name       string `json:"name"`
    Email      string `json:"email"`
}

func handlerFunc(msg string) func(echo.Context) error {
    return func(c echo.Context) error {
        return c.String(http.StatusOK, msg)
    }
}

func allUsers(db *gorm.DB) func(echo.Context) error {
    return func(c echo.Context) error {
        var users []User
        db.Find(&users)
        fmt.Println("{}", users)

        return c.JSON(http.StatusOK, users)
    }
}

func newUser(db *gorm.DB) func(echo.Context) error {
    return func(c echo.Context) error {
        name := c.Param("name")
        email := c.Param("email")
        db.Create(&User{Name: name, Email: email})
        return c.String(http.StatusOK, name+" user successfully created")
    }
}

func deleteUser(db *gorm.DB) func(echo.Context) error {
    return func(c echo.Context) error {
        name := c.Param("name")

        var user User
        db.Where("name = ?", name).Find(&user)
        db.Delete(&user)

        return c.String(http.StatusOK, name+" user successfully deleted")
    }
}

func updateUser(db *gorm.DB) func(echo.Context) error {
    return func(c echo.Context) error {
        name := c.Param("name")
        email := c.Param("email")
        var user User
        db.Where("name=?", name).Find(&user)
        user.Email = email
        db.Save(&user)
        return c.String(http.StatusOK, name+" user successfully updated")
    }
}

func usersByPage(db *gorm.DB) func(echo.Context) error {
    return func(c echo.Context) error {
        limit, _ := strconv.Atoi(c.QueryParam("limit"))
        page, _ := strconv.Atoi(c.QueryParam("page"))
        var result []User
        db.Limit(limit).Offset(limit * (page - 1)).Find(&result)
        return c.JSON(http.StatusOK, result)
    }
}

func handleRequest(db *gorm.DB) {
    e := echo.New()

    e.GET("/users", allUsers(db))
    e.GET("/user", usersByPage(db))
    e.POST("/user/:name/:email", newUser(db))
    e.DELETE("/user/:name", deleteUser(db))
    e.PUT("/user/:name/:email", updateUser(db))

    e.Logger.Fatal(e.Start(":3000"))
}

func initialMigration(db *gorm.DB) {

    db.AutoMigrate(&User{})
}

func main() {
    fmt.Println("Go ORM tutorial")
    db, err := gorm.Open("sqlite3", "sqlite3gorm.db")
    if err != nil {
        fmt.Println(err.Error())
        panic("failed to connect database")
    }
    defer db.Close()
    initialMigration(db)
    handleRequest(db)
}