package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"slices"
	"time"

	"github.com/caarlos0/env/v11"
	"github.com/gin-gonic/gin"
)

func ping(c *gin.Context) {
	c.String(http.StatusOK, "Pong!")
}

func authMiddleware(appConfig *AppConfig) gin.HandlerFunc {
	return func(ctx *gin.Context) {
		if appConfig.Secret != "" {
			if ctx.Request.Header.Get("PQM_AUTH") != appConfig.Secret {
				ctx.Abort()
				ctx.String(http.StatusForbidden, "拜拜")
				return
			}
		}
		ctx.Next()
	}
}

type AppConfig struct {
	Secret   string `env:"PQM_SECRET"`
	DataPath string `env:"PQM_DATA_PATH" envDefault:"data.json"`
}

type PMemo struct {
	Content     string    `json:"content"`
	CreatedDate time.Time `json:"created_date"`
}

type PMemoFilter struct {
	Till time.Time `json:"till"`
}

type AppData struct {
	Memos []PMemo `json:"memos"`
}

func SaveData(appConfig *AppConfig, data *AppData) error {
	dat, err := json.Marshal(data)
	if err != nil {
		return err
	}

	err = os.WriteFile(appConfig.DataPath, dat, os.FileMode(0o666))
	if err != nil {
		return err
	}
	return nil
}

func LoadData(appConfig *AppConfig) AppData {
	var appData AppData

	dat, err := os.ReadFile(appConfig.DataPath)
	if err != nil {
		appData = AppData{Memos: []PMemo{}}
		SaveData(appConfig, &appData)
		return appData
	}

	err = json.Unmarshal(dat, &appData)
	if err != nil {
		appData = AppData{Memos: []PMemo{}}
	}

	return appData
}

func main() {
	var config AppConfig
	err := env.Parse(&config)
	if err != nil {
		fmt.Println("读取环境变量出错啦！")
		panic(err)
	}

	appData := LoadData(&config)

	r := gin.Default()
	r.Use(authMiddleware(&config))
	r.GET("/", func(ctx *gin.Context) {
		ping(ctx)
	})
	r.GET("/all", func(ctx *gin.Context) {
		ctx.AsciiJSON(http.StatusOK, appData)
	})
	r.PUT("/create", func(ctx *gin.Context) {
		var content string
		if err := ctx.BindPlain(&content); err != nil {
			ctx.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		memo := PMemo{
			Content:     content,
			CreatedDate: time.Now(),
		}
		appData.Memos = append(appData.Memos, memo)
		if err := SaveData(&config, &appData); err != nil {
			ctx.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		ctx.JSON(http.StatusOK, gin.H{"error": "ok", "data": memo})
	})
	r.DELETE("/all", func(ctx *gin.Context) {
		appData.Memos = []PMemo{}
		if err := SaveData(&config, &appData); err != nil {
			ctx.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		ctx.JSON(http.StatusOK, gin.H{"error": "ok"})
	})
	r.POST("/filtered", func(ctx *gin.Context) {
		var filter PMemoFilter
		if err := ctx.BindJSON(&filter); err != nil {
			ctx.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}

		memos := slices.Collect(func(yield func(PMemo) bool) {
			for _, memo := range appData.Memos {
				if filter.Till.After(memo.CreatedDate) {
					if !yield(memo) {
						return
					}
				}
			}
		})
		ctx.JSON(http.StatusOK, gin.H{"error": "ok", "data": gin.H{"memos": memos}})
	})
	r.DELETE("/filtered", func(ctx *gin.Context) {
		var filter PMemoFilter
		if err := ctx.BindJSON(&filter); err != nil {
			ctx.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}

		appData.Memos = slices.Collect(func(yield func(PMemo) bool) {
			for _, memo := range appData.Memos {
				if !filter.Till.After(memo.CreatedDate) {
					if !yield(memo) {
						return
					}
				}
			}
		})
		if err := SaveData(&config, &appData); err != nil {
			ctx.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		ctx.JSON(http.StatusOK, gin.H{"error": "ok", "data": appData})
	})

	r.Run()
}