package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"path"
	"strconv"

	"hakurei.app/internal/info"
	"hakurei.app/internal/pkg"
	"hakurei.app/internal/rosa"
)

type InfoPayload struct {
	Count          int    `json:"count"`
	HakureiVersion string `json:"hakurei_version"`
}

func NewInfoPayload(index *PackageIndex) InfoPayload {
	count := len(index.sorts[0])
	return InfoPayload{
		Count:          count,
		HakureiVersion: info.Version(),
	}
}

func serveInfo(index *PackageIndex) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Header().Set("Content-Type", "text/json; charset=utf-8")
		w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
		WritePayload(w, NewInfoPayload(index))
	}
}

func serveStatus(index *PackageIndex) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		download := path.Dir(r.URL.Path) == "/status"
		if index == nil {
			http.Error(w, "index is nil", http.StatusInternalServerError)
			return
		}
		name := path.Base(r.URL.Path)
		p, ok := rosa.ResolveName(name)
		if !ok {
			http.NotFound(w, r)
			return
		}
		m := rosa.GetMetadata(p)
		pk, ok := index.names[m.Name]
		if !ok {
			http.NotFound(w, r)
			return
		}
		if len(pk.status) > 0 {
			if download {
				w.Header().Set("Content-Type", "application/octet-stream")
			} else {
				w.Header().Set("Content-Type", "text/plain; charset=utf-8")
			}
			if download {
				var version string
				if pk.Version != "\u0000" {
					version = pk.Version
				} else {
					version = "unknown"
				}
				w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s-%s-%s.log\"", pk.Name, version, pkg.Encode(pk.ident.Value())))
			}

			w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
			w.WriteHeader(http.StatusOK)
			_, err := io.Copy(w, bytes.NewReader(pk.status))
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
			}
		} else {
			http.NotFound(w, r)
		}
	}
}

type GetPayload struct {
	Count  int                 `json:"count"`
	Values []PackageIndexEntry `json:"values"`
}

func NewGetPayload(values []*PackageIndexEntry) GetPayload {
	count := len(values)
	v := make([]PackageIndexEntry, count)
	for i, _ := range values {
		v[i] = *values[i]
	}
	return GetPayload{
		Count:  count,
		Values: v,
	}
}

func serveGet(index *PackageIndex) func(http.ResponseWriter, *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		q := r.URL.Query()
		limit, err := strconv.Atoi(q.Get("limit"))
		if err != nil || limit > 100 || limit < 1 {
			http.Error(w, fmt.Sprintf("limit must be an integer between 1 and 100"), http.StatusBadRequest)
			return
		}
		i, err := strconv.Atoi(q.Get("index"))
		if err != nil || i >= len(index.sorts[0]) || i < 0 {
			http.Error(w, fmt.Sprintf("index must be an integer between 0 and %d", len(index.sorts[0])-1), http.StatusBadRequest)
			return
		}
		sort, err := strconv.Atoi(q.Get("sort"))
		if err != nil || sort >= len(index.sorts) || sort < 0 {
			http.Error(w, fmt.Sprintf("sort must be an integer between 0 and %d", len(index.sorts)-1), http.StatusBadRequest)
			return
		}
		values := index.sorts[sort][i:min(i+limit, len(index.sorts[sort]))]
		WritePayload(w, NewGetPayload(values))
	}
}

const ApiVersion = "v1"

func apiRoutes(mux *http.ServeMux, index *PackageIndex) {
	mux.HandleFunc(fmt.Sprintf("GET /api/%s/info", ApiVersion), serveInfo(index))
	mux.HandleFunc(fmt.Sprintf("GET /api/%s/get", ApiVersion), serveGet(index))
	mux.HandleFunc(fmt.Sprintf("GET /api/%s/status/", ApiVersion), serveStatus(index))
	mux.HandleFunc("GET /status/", serveStatus(index))
}

func WritePayload(w http.ResponseWriter, payload any) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
	w.Header().Set("Pragma", "no-cache")
	w.Header().Set("Expires", "0")
	err := json.NewEncoder(w).Encode(payload)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}