package api

import (
	"arimelody-web/controller"
	"arimelody-web/model"
	"arimelody-web/global"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"strings"
	"time"

	"golang.org/x/crypto/bcrypt"
)

func handleLogin() http.HandlerFunc {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.Method != http.MethodPost {
            http.NotFound(w, r)
            return
        }

        type LoginRequest struct {
            Username string `json:"username"`
            Password string `json:"password"`
        }

        credentials := LoginRequest{}
        err := json.NewDecoder(r.Body).Decode(&credentials)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        account, err := controller.GetAccount(global.DB, credentials.Username)
        if err != nil {
            if strings.Contains(err.Error(), "no rows") {
                http.Error(w, "Invalid username or password", http.StatusBadRequest)
                return
            }
            fmt.Fprintf(os.Stderr, "WARN: Failed to retrieve account: %s\n", err.Error())
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        err = bcrypt.CompareHashAndPassword(account.Password, []byte(credentials.Password))
        if err != nil {
            http.Error(w, "Invalid username or password", http.StatusBadRequest)
            return
        }

        // TODO: sessions and tokens

        w.WriteHeader(http.StatusOK)
        w.Write([]byte("Logged in successfully. TODO: Session tokens\n"))
    })
}

func handleAccountRegistration() http.HandlerFunc {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.Method != http.MethodPost {
            http.NotFound(w, r)
            return
        }

        type RegisterRequest struct {
            Username    string `json:"username"`
            Email       string `json:"email"`
            Password    string `json:"password"`
            Code        string `json:"code"`
        }

        credentials := RegisterRequest{}
        err := json.NewDecoder(r.Body).Decode(&credentials)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        // make sure code exists in DB
        invite := model.Invite{}
        err = global.DB.Get(&invite, "SELECT * FROM invite WHERE code=$1", credentials.Code)
        if err != nil {
            if strings.Contains(err.Error(), "no rows") {
                http.Error(w, "Invalid invite code", http.StatusBadRequest)
                return
            }
            fmt.Fprintf(os.Stderr, "WARN: Failed to retrieve invite: %s\n", err.Error())
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        if time.Now().After(invite.ExpiresAt) {
            http.Error(w, "Invalid invite code", http.StatusBadRequest)
            _, err = global.DB.Exec("DELETE FROM invite WHERE code=$1", credentials.Code)
            if err != nil { fmt.Fprintf(os.Stderr, "WARN: Failed to delete expired invite: %s\n", err.Error()) }
            return
        }

        hashedPassword, err := bcrypt.GenerateFromPassword([]byte(credentials.Password), bcrypt.DefaultCost)
        if err != nil {
            fmt.Fprintf(os.Stderr, "WARN: Failed to generate password hash: %s\n", err.Error())
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        account := model.Account{
            Username: credentials.Username,
            Password: hashedPassword,
            Email: credentials.Email,
            AvatarURL: "/img/default-avatar.png",
        }
        err = controller.CreateAccount(global.DB, &account)
        if err != nil {
            fmt.Fprintf(os.Stderr, "WARN: Failed to create account: %s\n", err.Error())
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        _, err = global.DB.Exec("DELETE FROM invite WHERE code=$1", credentials.Code)
        if err != nil { fmt.Fprintf(os.Stderr, "WARN: Failed to delete expired invite: %s\n", err.Error()) }

        w.WriteHeader(http.StatusCreated)
        w.Write([]byte("Account created successfully\n"))
    })
}

func handleDeleteAccount() http.HandlerFunc {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        if r.Method != http.MethodPost {
            http.NotFound(w, r)
            return
        }

        type LoginRequest struct {
            Username string `json:"username"`
            Password string `json:"password"`
        }

        credentials := LoginRequest{}
        err := json.NewDecoder(r.Body).Decode(&credentials)
        if err != nil {
            http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
            return
        }

        account, err := controller.GetAccount(global.DB, credentials.Username)
        if err != nil {
            if strings.Contains(err.Error(), "no rows") {
                http.Error(w, "Invalid username or password", http.StatusBadRequest)
                return
            }
            fmt.Fprintf(os.Stderr, "WARN: Failed to retrieve account: %s\n", err.Error())
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        err = bcrypt.CompareHashAndPassword(account.Password, []byte(credentials.Password))
        if err != nil {
            http.Error(w, "Invalid username or password", http.StatusBadRequest)
            return
        }

        err = controller.DeleteAccount(global.DB, account.ID)
        if err != nil {
            fmt.Fprintf(os.Stderr, "WARN: Failed to delete account: %s\n", err.Error())
            http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
            return
        }

        w.WriteHeader(http.StatusOK)
        w.Write([]byte("Account deleted successfully\n"))
    })
}