class MultipleFilesWidget {
    constructor(div) {
        this.root = div
        this.fieldName = this.root.getAttribute('data-field')
        this.fileList = []
        this.element = {
            list: this.root.querySelector('.filewidget--list'),
            uploadButton: this.root.querySelector('.filewidget--input'),
            field: document.querySelector(`[name="${this.fieldName}"]`)
        }

        const self = this

        // Set up jquery-fileupload
        $(this.element.uploadButton).fileupload({
            dataType: 'json',
            paramName: 'file',
            done: function (e, data) {
                // process server response
                if (data.result.is_valid) {
                    self.fileFinished.bind(self)(data.result)
                } else {
                    self.fileFailed.bind(self)(data)
                }
            },
            add: function (e, data) {
                $.each(data.files, (index, file) => {
                    self.addFile.bind(self)(null, file.name, self.setFileInProgress.bind(self))
                })

                data.process().done(function () {
                    data.submit()
                })
            },
            progress: function(e, data) {
                console.log('progress event')
                console.log(e, data)
            }
        })

        // If there is something in the field, we need to restore our state
        if (this.element.field.value) {
            this.rebuildListFromField()
        }

        // Set up listening for restore
        this.element.field.addEventListener('change', evt => {
            this.rebuildListFromField()
        })
    }

    rebuildListFromField() {
        let idList = this.element.field.value.split(",")
        for (let id of idList) {
            this.addFile(id, `Saved upload (id ${id})`, this.setFileDone.bind(this))
        }
        this.viewFileList()
    }

    addFile(id, name, stateFunc) {
        let li = document.createElement('li')
        li.className = 'filewidget--file'
        li.innerHTML =
           `<i class='filewidget--file--icon'></i> <span class='filewidget--file--name'></span>
            <span class='filewidget--file--actions'></span>`

        let file = {
            root: li,
            element: {
                icon: li.querySelector('.filewidget--file--icon'),
                name: li.querySelector('.filewidget--file--name'),
                actions: li.querySelector('.filewidget--file--actions'),
            },
            name: name,
            id: id || null,
        }

        stateFunc(file)

        this.fileList.push(file)
        this.viewFileList()
    }

    removeFile(file) {
        // Remove file from display
        this.element.list.removeChild(file.root)

        // Remove file from fileList
        this.fileList = this.fileList.filter(cmpFile => cmpFile === file)
    }

    fileFinished(serverResponse) {
        // Using data, find the file
        let file = this.fileList.filter(file => file.name === serverResponse.name)[0]

        // Set the ID
        file.id = serverResponse.id

        // Set the file state now it's finished
        this.setFileDone(file)
        this.viewFileList()

        // Do this last tho
        this.updateFormField()
    }

    fileFailed(serverResponse) {
        let errors = Object.values(serverResponse.result.errors).join(' ')

        console.error('File upload failed: ' + errors)
        console.error(serverResponse)

        // Using data, find the file
        let file = this.fileList.filter(file => file.name === serverResponse.files[0].name)[0]

        // Set the file state now it's finished
        this.setFileFailed(file, errors)
        this.viewFileList()
    }

    //
    // Update the field that keeps track of file IDs
    //

    updateFormField() {
        let oldVal = this.element.field.value
        this.element.field.value = this.fileList.filter(f => f.id != null)
                                                .map(f => f.id)
                                                .toString()

        // Mark form as dirty
        if (this.element.field.value !== oldVal) {
            document.getElementById('case-study-form').dispatchEvent(new Event('dirty'))
        }
    }

    //
    // Manage the state of individual files in the widget
    //

    setFileState(file, state) {
        file.element.icon.classList = `filewidget--file--icon ${state.iconClassList}`
        file.element.name.innerText = state.fileName
        file.element.actions.innerHTML = state.actions || ''
    }

    setFileFailed(file, errors) {
        this.setFileState(file, {
            iconClassList: 'fa fa-exclamation-triangle',
            fileName: `FAILED: ${errors} ('${file.name}')`
        })
    }

    setFileInProgress(file) {
        this.setFileState(file, {
            iconClassList: 'fa fa-spinner fa-spin',
            fileName: `${file.name} (uploading...)`
        })
    }

    setFileDeletingInProgress(file) {
        this.setFileState(file, {
            iconClassList: 'fa fa-spinner fa-spin',
            fileName: `Deleting...`
        })
    }

    setFileDeletingFailed(file) {
        this.setFileState(file, {
            iconClassList: 'fa fa-exclamation-triangle',
            fileName: `${file.name} (delete failed!)`
        })
    }

    setFileDone(file) {
        this.setFileState(file, {
            iconClassList: 'fa fa-file-o',
            fileName: `${file.name}`,
            actions: '<a title="Remove"><i class="fa fa-times"></i></a>'
        })

        file.element.actions.querySelector('a').addEventListener('click', () => {
            this.setFileDeletingInProgress(file)

            return fetch(`/files/delete/${file.id}/`, {
                method: 'POST',
                credentials: "same-origin",
                headers: {
                    "X-CSRFToken": jQuery("[name=csrfmiddlewaretoken]").val(),
                }
            }).then(response => {
                if (response.ok) {
                    this.removeFile(file)
                } else {
                    this.setFileDeletingFailed(file)
                }
            })
        })
    }

    //
    // Redraw the file list
    //

    viewFileList() {
        for (let file of this.fileList) {
            // Check if it's appended to the list
            if (!this.element.list.contains(file.root)) {
                this.element.list.appendChild(file.root)
            }
        }
    }
}

$(function() {
    window.images = new MultipleFilesWidget(
        document.querySelector('[data-field=images_files]')
    )
    window.official_project_documents = new MultipleFilesWidget(
        document.querySelector('[data-field=official_project_documents_files]')
    )
    window.other_documents = new MultipleFilesWidget(
        document.querySelector('[data-field=other_documents_files]')
    )
    window.shapefiles = new MultipleFilesWidget(
        document.querySelector('[data-field=shapefiles_files]')
    )
})