import QtQuick 2.2
import "PropfindParser.js" as Prop

// Minimal WebDAV client over XMLHttpRequest. One request at a time
// (busy flag); 30 s watchdog turns hangs into a failed() signal.
Item {
    id: dav

    property bool busy: false

    signal listReady(var entries)
    signal fileReady(string content)
    signal writeDone()
    signal deleteDone()
    signal connOk()
    signal failed(string message)

    property var currentXhr: null

    Timer {
        id: watchdog
        interval: 30000
        repeat: false
        onTriggered: {
            if (dav.currentXhr) {
                dav.currentXhr.abort()
                dav.currentXhr = null
            }
            dav.busy = false
            dav.failed(qsTr("Network timeout"))
        }
    }

    function authHeader() {
        var user = appSettings.username
        if (!user) return ""
        return "Basic " + Qt.btoa(user + ":" + appSettings.password)
    }

    function encodeRel(rel) {
        if (!rel) return rel
        var parts = rel.split("/")
        var out = []
        for (var i = 0; i < parts.length; i++) out.push(encodeURIComponent(parts[i]))
        return out.join("/")
    }

    function fullUrl(rel) {
        var base = String(appSettings.serverUrl).replace(/\s+$/, "")
        if (!base) return ""
        if (rel && rel !== "") {
            if (base.charAt(base.length - 1) !== "/") base += "/"
            base += encodeRel(rel)
        }
        return base
    }

    function request(method, url, body, onDone) {
        if (busy) {
            failed(qsTr("Request already in progress"))
            return
        }
        busy = true
        var xhr = new XMLHttpRequest()
        currentXhr = xhr
        xhr.open(method, url, true)
        var auth = authHeader()
        if (auth) xhr.setRequestHeader("Authorization", auth)
        if (method === "PROPFIND") xhr.setRequestHeader("Depth", "1")
        if (method === "PUT") xhr.setRequestHeader("Content-Type", "text/markdown; charset=utf-8")
        xhr.onreadystatechange = function () {
            if (xhr.readyState !== 4) return
            watchdog.stop()
            if (currentXhr === xhr) {
                currentXhr = null
                busy = false
                onDone(xhr)
            }
            // else: aborted by the watchdog — already signalled
        }
        xhr.send(body || "")
        watchdog.restart()
    }

    function listDir(relPath) {
        request("PROPFIND", fullUrl(relPath || ""), "", function (xhr) {
            if (xhr.status >= 200 && xhr.status < 300) {
                var entries = Prop.parse(xhr.responseText, appSettings.serverUrl)
                listReady(entries)
            } else {
                failed(statusMessage(xhr.status))
            }
        })
    }

    function readFile(relPath) {
        request("GET", fullUrl(relPath), "", function (xhr) {
            if (xhr.status >= 200 && xhr.status < 300) {
                fileReady(xhr.responseText)
            } else {
                failed(statusMessage(xhr.status))
            }
        })
    }

    function writeFile(relPath, content) {
        request("PUT", fullUrl(relPath), content, function (xhr) {
            if (xhr.status >= 200 && xhr.status < 300) {
                writeDone()
            } else {
                failed(statusMessage(xhr.status))
            }
        })
    }

    function deleteFile(relPath) {
        request("DELETE", fullUrl(relPath), "", function (xhr) {
            if (xhr.status >= 200 && xhr.status < 300) {
                deleteDone()
            } else {
                failed(statusMessage(xhr.status))
            }
        })
    }

    function testConnection() {
        request("PROPFIND", fullUrl(""), "", function (xhr) {
            if (xhr.status >= 200 && xhr.status < 300) {
                connOk()
            } else {
                failed(statusMessage(xhr.status))
            }
        })
    }

    function statusMessage(status) {
        if (status === 401) return qsTr("Invalid credentials (401)")
        if (status === 403) return qsTr("Access denied (403)")
        if (status === 404) return qsTr("Folder not found (404) — check the URL")
        if (status === 405) return qsTr("WebDAV not available (405) — the URL must point to a DAV folder")
        if (status === 0) return qsTr("Server unreachable")
        if (status >= 500) return qsTr("Server error (%1)").arg(status)
        return qsTr("HTTP error %1").arg(status)
    }
}