import { promptUpload } from "./prompt_upload.js";
import { slugify } from "./utils.js";
import { HtmlExporter } from "./html_exporter.js";
import { KarlkoderCodec } from "./karlkoder_codec.js";

export class ProjectSaveHandler {
    constructor(editor, assetEditor, assetProvider, sessionSaveHandler, projectName) {
        this.editor = editor;
        this.assetEditor = assetEditor;
        this.sessionSaveHandler = sessionSaveHandler;

        this.htmlExporter = new HtmlExporter(assetProvider);

        this.projectName = projectName;

        this.fileHandles = {}; // Used for Chromium file picker
        this.saveName = null;
        this.isSaved = true;

        editor.addEventListener("change", () => {
            this.isSaved = false;
        });

        assetEditor.addChangeListener(() => {
            this.isSaved = false;
        });
    }

    async showLoadFilePrompt() {
        const files = await promptUpload(".karlkode", false);
        if (files.length === 0) {
            return;
        }

        if (files.length > 1) {
            throw new Error(
                `unreachable: something went wrong ! files.length > 1 : files.length = ${files.length}`,
            );
        }

        await this.loadFromFile(files[0]);
    }

    async loadFromFile(file) {
        if (
            !this.isSaved &&
            !confirm(
                "Your project has not been saved. Loading a new project will override your current one. Continue?",
            )
        ) {
            return;
        }

        const items = KarlkoderCodec.de(
            await fetch(URL.createObjectURL(file)).then((x) => x.bytes()),
        );

        const assets = items
            .filter((x) => x.tag === "asset")
            .map((x) => {
                delete x.tag;
                return x;
            });

        const code = items.find((x) => x.tag === "code");
        delete code.tag;

        await this.assetEditor.importAssets(
            assets.map(({ name, mime, content }) => {
                const file = new File([content], name, { type: mime });

                return { name, file };
            }),
        );

        const dec = new TextDecoder();
        this.sessionSaveHandler.saveEditorCode(dec.decode(code.content));
        this.sessionSaveHandler.saveProjectName(code.name);

        this.isSaved = true;
        this.fileHandles = {};
    }

    async saveFile() {
        const saved = await this.downloadFile(
            "project",
            this.getSaveFileName(),
            await KarlkoderCodec.en(
                this.projectName.value,
                this.editor.getValue(),
                await this.assetEditor.getAssets(),
            ),
            ".karlkode",
            "application/x-karlkode",
        );

        this.isSaved = saved;

        if (globalThis.chrome) {
            this.showSavedStatus(saved, saved ? "Saved" : "Not saved");
        }
    }

    async exportProject() {
        const html = await this.htmlExporter.export(this.projectName.value, this.editor.getValue());

        const exported = await this.downloadFile(
            "export",
            this.getSaveFileName(),
            html,
            ".html",
            "text/html",
        );

        if (globalThis.chrome) {
            this.showSavedStatus(exported, exported ? "Exported" : "Not exported");
        }
    }

    getSaveFileName() {
        if (this.saveName) {
            return this.saveName;
        }

        return slugify(this.projectName.value) || "project";
    }

    showSavedStatus(success, status) {
        const saveStatus = document.querySelector("#save-status");
        saveStatus.textContent = (success ? "✓ " : "× ") + status;
        saveStatus.style.backgroundColor = success ? "#43A047" : "#E53935";
        saveStatus.style.transition = "";
        saveStatus.style.opacity = 1;

        setTimeout(() => {
            saveStatus.style.transition = "opacity 1s ease-out";
            saveStatus.style.opacity = 0;
        }, 1500);
    }

    async downloadFile(id, name, content, extension, mime) {
        if ("showSaveFilePicker" in globalThis) {
            try {
                this.fileHandles[id] ??= await globalThis.showSaveFilePicker({
                    id: "karlkoder",
                    startIn: "documents",
                    suggestedName: name + extension,
                    types: [{
                        accept: {
                            [mime]: [extension],
                        },
                    }],
                });

                const stream = await this.fileHandles[id].createWritable();
                await stream.write(content);
                await stream.close();

                return true;
            } catch (e) {
                // Throws AbortError or NotAllowedError on cancel

                console.log("file picker error", e);

                this.fileHandles[id] = null; // Ask for new file handle next time

                return false;
            }
        }

        const filename = prompt("Filename?", name);
        if (!filename) {
            return false;
        }

        this.saveName = filename;

        const blob = new Blob([content], { type: mime });
        const url = URL.createObjectURL(blob);

        const element = document.createElement("a");

        element.href = url;
        element.download = filename.endsWith(extension) ? filename : filename + extension;
        element.style.display = "none";

        document.body.appendChild(element);

        element.click();

        document.body.removeChild(element);

        return true;
    }
}