package web

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"strconv"
	"strings"
	"time"

	"gardomatic.kleiax.de/lib/client"
)

const maxJournalFormSize = 100 << 20

type journalForm struct {
	Title           string
	Body            string
	DateTime        string
	Keywords        string
	TagSuggestions  []string
	Attachments     []client.JournalAttachment
	LibraryImageIDs []int
	Errors          map[string]string
}

type gardenEntryView struct {
	entryType string
	path      string
}

var (
	journalEntryView  = gardenEntryView{entryType: client.JournalEntryTypeJournal, path: "journal"}
	pinboardEntryView = gardenEntryView{entryType: client.JournalEntryTypePinboard, path: "pinboard"}
)

func (app *application) journal(w http.ResponseWriter, r *http.Request) {
	app.gardenEntries(w, r, journalEntryView)
}

func (app *application) pinboard(w http.ResponseWriter, r *http.Request) {
	app.gardenEntries(w, r, pinboardEntryView)
}

func (app *application) gardenEntries(w http.ResponseWriter, r *http.Request, view gardenEntryView) {
	gardenID, err := app.readPathID(r, "gardenID")
	if err != nil {
		app.notFound(w)
		return
	}
	apiClient := client.FromContext(r.Context())
	garden, _, err := apiClient.Garden(r.Context(), gardenID)
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	entries, _, err := apiClient.JournalEntriesByType(r.Context(), gardenID, view.entryType)
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	data := app.newTemplateData(r)
	entries, data.Pagination = paginateCollection(r, entries)
	data.Garden, data.JournalEntries, data.ContentKind = &garden, entries, view.entryType
	app.render(w, http.StatusOK, "journal.tmpl", data)
}

func (app *application) journalCreate(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryCreate(w, r, journalEntryView)
}

func (app *application) pinboardCreate(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryCreate(w, r, pinboardEntryView)
}

func (app *application) gardenEntryCreate(w http.ResponseWriter, r *http.Request, view gardenEntryView) {
	form := journalForm{DateTime: time.Now().Format("2006-01-02T15:04"), Errors: map[string]string{}}
	app.loadJournalTagSuggestions(r, &form)
	app.renderJournalForm(w, r, form, http.StatusOK, 0, view)
}

func (app *application) journalEdit(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryEdit(w, r, journalEntryView)
}

func (app *application) pinboardEdit(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryEdit(w, r, pinboardEntryView)
}

func (app *application) gardenEntryEdit(w http.ResponseWriter, r *http.Request, view gardenEntryView) {
	gardenID, err := app.readPathID(r, "gardenID")
	if err != nil {
		app.notFound(w)
		return
	}
	entryID, err := app.readPathID(r, "entryID")
	if err != nil {
		app.notFound(w)
		return
	}
	entry, _, err := client.FromContext(r.Context()).JournalEntry(r.Context(), gardenID, entryID)
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	if entry.EntryType != view.entryType {
		app.notFound(w)
		return
	}
	form := journalForm{Title: entry.Title, Body: entry.Body, DateTime: entry.CreatedAt.In(time.Local).Format("2006-01-02T15:04"), Keywords: strings.Join(entry.Tags, ", "), Attachments: entry.Attachments, Errors: map[string]string{}}
	app.loadJournalTagSuggestions(r, &form)
	app.renderJournalForm(w, r, form, http.StatusOK, entryID, view)
}

func (app *application) journalSave(w http.ResponseWriter, r *http.Request) {
	app.gardenEntrySave(w, r, journalEntryView)
}

func (app *application) pinboardSave(w http.ResponseWriter, r *http.Request) {
	app.gardenEntrySave(w, r, pinboardEntryView)
}

func (app *application) gardenEntrySave(w http.ResponseWriter, r *http.Request, view gardenEntryView) {
	gardenID, err := app.readPathID(r, "gardenID")
	if err != nil {
		app.notFound(w)
		return
	}
	entryID := 0
	if id, readErr := app.readPathID(r, "entryID"); readErr == nil {
		entryID = id
	}
	r.Body = http.MaxBytesReader(w, r.Body, maxJournalFormSize)
	if err = r.ParseMultipartForm(16 << 20); err != nil {
		app.clientError(w, http.StatusRequestEntityTooLarge)
		return
	}
	form := journalForm{Title: strings.TrimSpace(r.FormValue("title")), Body: strings.TrimSpace(r.FormValue("body")), DateTime: r.FormValue("date_time"), Keywords: r.FormValue("keywords"), Errors: map[string]string{}}
	for _, value := range r.MultipartForm.Value["library_image_id"] {
		if id, parseErr := strconv.Atoi(value); parseErr == nil && id > 0 {
			form.LibraryImageIDs = append(form.LibraryImageIDs, id)
		}
	}
	if form.DateTime == "" {
		form.DateTime = time.Now().Format("2006-01-02T15:04")
	}
	app.loadJournalTagSuggestions(r, &form)
	if form.Title == "" && view.entryType == client.JournalEntryTypeJournal {
		form.Errors["title"] = "Ein Titel ist erforderlich."
	}
	if len(form.Body) > 100_000 {
		form.Errors["body"] = "Der Text darf höchstens 100.000 Zeichen enthalten."
	}
	createdAt, parseErr := time.ParseInLocation("2006-01-02T15:04", form.DateTime, time.Local)
	if parseErr != nil {
		form.Errors["date_time"] = "Bitte ein gültiges Datum und eine gültige Uhrzeit angeben."
	}
	apiClient := client.FromContext(r.Context())
	if entryID > 0 {
		if existing, _, getErr := apiClient.JournalEntry(r.Context(), gardenID, entryID); getErr == nil {
			if existing.EntryType != view.entryType {
				app.notFound(w)
				return
			}
			form.Attachments = existing.Attachments
		} else {
			app.handleAPIError(w, r, getErr)
			return
		}
	}
	if len(form.Errors) > 0 {
		app.renderJournalForm(w, r, form, http.StatusUnprocessableEntity, entryID, view)
		return
	}
	entryType := view.entryType
	input := client.JournalEntryInput{Title: &form.Title, Body: &form.Body, CreatedAt: &createdAt, Tags: parseKeywords(form.Keywords), EntryType: &entryType}
	var entry client.JournalEntry
	if entryID > 0 {
		entry, _, err = apiClient.UpdateJournalEntry(r.Context(), gardenID, entryID, input)
	} else {
		entry, _, err = apiClient.CreateJournalEntry(r.Context(), gardenID, input)
	}
	if err != nil {
		var apiError *client.APIError
		if errors.As(err, &apiError) && apiError.StatusCode == http.StatusUnprocessableEntity {
			form.Errors = apiError.Validation
			app.renderJournalForm(w, r, form, http.StatusUnprocessableEntity, entryID, view)
			return
		}
		app.handleAPIError(w, r, err)
		return
	}
	entryID = entry.ID
	for _, value := range r.MultipartForm.Value["remove_attachment"] {
		if id, parseErr := strconv.Atoi(value); parseErr == nil {
			_, _ = apiClient.DeleteJournalAttachment(r.Context(), gardenID, entryID, id)
		}
	}
	body := form.Body
	for index, header := range r.MultipartForm.File["embedded_images"] {
		attachment, uploadErr := app.uploadJournalFile(r, apiClient, gardenID, entryID, header)
		if uploadErr != nil {
			app.handleAPIError(w, r, uploadErr)
			return
		}
		url := webPath(view.path+".attachment", gardenID, entryID, attachment.ID)
		body = strings.ReplaceAll(body, fmt.Sprintf("/pending-journal-image/%d", index), url)
	}
	for _, header := range r.MultipartForm.File["attachments"] {
		if _, uploadErr := app.uploadJournalFile(r, apiClient, gardenID, entryID, header); uploadErr != nil {
			app.handleAPIError(w, r, uploadErr)
			return
		}
	}
	for _, imageID := range form.LibraryImageIDs {
		if _, _, attachErr := apiClient.AttachJournalLibraryImage(r.Context(), gardenID, entryID, imageID); attachErr != nil {
			app.handleAPIError(w, r, attachErr)
			return
		}
	}
	if body != form.Body {
		_, _, err = apiClient.UpdateJournalEntry(r.Context(), gardenID, entryID, client.JournalEntryInput{Body: &body})
	}
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	http.Redirect(w, r, webPath("garden."+view.path, gardenID), http.StatusSeeOther)
}

func (app *application) uploadJournalFile(r *http.Request, apiClient *client.Client, gardenID, entryID int, header *multipart.FileHeader) (client.JournalAttachment, error) {
	file, err := header.Open()
	if err != nil {
		return client.JournalAttachment{}, err
	}
	defer file.Close()
	data, err := io.ReadAll(io.LimitReader(file, (25<<20)+1))
	if err != nil {
		return client.JournalAttachment{}, err
	}
	if len(data) > 25<<20 {
		return client.JournalAttachment{}, fmt.Errorf("anhang %q ist größer als 25 MB", header.Filename)
	}
	mediaType := strings.Split(header.Header.Get("Content-Type"), ";")[0]
	attachment, _, err := apiClient.UploadJournalAttachment(r.Context(), gardenID, entryID, header.Filename, mediaType, data)
	return attachment, err
}

func (app *application) journalDelete(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryDelete(w, r, journalEntryView)
}

func (app *application) pinboardDelete(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryDelete(w, r, pinboardEntryView)
}

func (app *application) gardenEntryDelete(w http.ResponseWriter, r *http.Request, view gardenEntryView) {
	gardenID, err := app.readPathID(r, "gardenID")
	if err != nil {
		app.notFound(w)
		return
	}
	entryID, err := app.readPathID(r, "entryID")
	if err != nil {
		app.notFound(w)
		return
	}
	apiClient := client.FromContext(r.Context())
	entry, _, err := apiClient.JournalEntry(r.Context(), gardenID, entryID)
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	if entry.EntryType != view.entryType {
		app.notFound(w)
		return
	}
	if _, err = apiClient.DeleteJournalEntry(r.Context(), gardenID, entryID); err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	http.Redirect(w, r, webPath("garden."+view.path, gardenID), http.StatusSeeOther)
}

func (app *application) journalAttachment(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryAttachment(w, r)
}

func (app *application) pinboardAttachment(w http.ResponseWriter, r *http.Request) {
	app.gardenEntryAttachment(w, r)
}

func (app *application) gardenEntryAttachment(w http.ResponseWriter, r *http.Request) {
	gardenID, err := app.readPathID(r, "gardenID")
	if err != nil {
		app.notFound(w)
		return
	}
	entryID, err := app.readPathID(r, "entryID")
	if err != nil {
		app.notFound(w)
		return
	}
	attachmentID, err := app.readPathID(r, "attachmentID")
	if err != nil {
		app.notFound(w)
		return
	}
	attachment, _, err := client.FromContext(r.Context()).JournalAttachment(r.Context(), gardenID, entryID, attachmentID)
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	w.Header().Set("Content-Type", attachment.MediaType)
	w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=%q", strings.ReplaceAll(attachment.FileName, "\"", "")))
	w.Header().Set("Cache-Control", "private, max-age=3600")
	http.ServeContent(w, r, attachment.FileName, attachment.CreatedAt, bytes.NewReader(attachment.Data))
}

func (app *application) renderJournalForm(w http.ResponseWriter, r *http.Request, form journalForm, status, entryID int, view gardenEntryView) {
	gardenID, err := app.readPathID(r, "gardenID")
	if err != nil {
		app.notFound(w)
		return
	}
	garden, _, err := client.FromContext(r.Context()).Garden(r.Context(), gardenID)
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	data := app.newTemplateData(r)
	data.Garden, data.Form, data.EntryID, data.UseJournalEditor, data.ContentKind = &garden, form, entryID, true, view.entryType
	data.Images, err = app.loadImageLibrary(r, gardenID)
	if err != nil {
		app.handleAPIError(w, r, err)
		return
	}
	app.render(w, status, "journal_form.tmpl", data)
}

func (app *application) loadJournalTagSuggestions(r *http.Request, form *journalForm) {
	gardenID, err := app.readPathID(r, "gardenID")
	if err != nil {
		return
	}
	if tags, _, tagErr := client.FromContext(r.Context()).GardenTags(r.Context(), gardenID); tagErr == nil {
		form.TagSuggestions = tags
	}
}