import QtQuick
import QtQuick.Layouts
import qs.Commons
import qs.Ui
import "Model.js" as Model

// Editor for one key. It edits a local draft and only writes to config.yaml when
// Save is pressed, so a half-typed command never reaches the running deck.
//
// Inputs are deliberately *not* two-way bound — neither the text fields nor the
// dropdowns. Typing into a QML TextField (or Ui/Dropdown selecting internally)
// writes the property directly and destroys any declarative binding on it, which
// would leave Revert unable to repaint the control. Instead the draft is the
// single source of truth: edit handlers push user input into it, and
// syncFields()/paramsSynced() push the draft back out whenever it changes
// underneath the user. Controls with focus (or an open popup) are skipped so a
// background poll can never move the cursor mid-keystroke.
Item {
  id: root

  property var service: null
  property var status: null
  property int keyIndex: -1
  property color foreground: Color.foreground
  property color accent: Color.accent
  property string fontFamily: Style.font.family

  signal closed()
  signal saved()

  readonly property color dim: Qt.darker(foreground, 1.55)

  readonly property var currentKey: {
    if (!status || keyIndex < 0) return null
    for (var i = 0; i < status.keys.length; i++) {
      if (Number(status.keys[i].index) === keyIndex) return status.keys[i]
    }
    return null
  }
  readonly property var original: Model.editorDraft(currentKey)
  readonly property bool isNew: currentKey === null

  // The working copy.
  property var draft: Model.editorDraft(null)

  // `touched` is set by user edits rather than derived from draft-vs-original.
  // A derived flag would be read by onCurrentKeyChanged while `original` was
  // still evaluating, which Qt reports as a binding loop.
  property bool touched: false
  readonly property bool dirty: touched && Model.draftDiffers(draft, original)
  readonly property bool usingModule: String(draft.module || "") !== ""

  // The parameter Repeater's model. Rebuilt ONLY when the parameter name set
  // changes (module/function switch), never on keystrokes or status polls —
  // a model whose identity churned with `draft` or `status` would destroy and
  // recreate the delegates, dropping focus after every typed character.
  property var paramNames: []

  // Fired when param VALUES in the draft changed underneath the delegates
  // (reset, module switch). Delegates re-pull their value unless focused.
  signal paramsSynced()

  onKeyIndexChanged: reset()

  // A background poll replaces the status object every few seconds. Adopt the
  // refreshed key only when the user has nothing in flight.
  //
  // The adoption is deferred: `currentKey` is evaluated lazily, so the first
  // read of `dirty` (via `original`) is what triggers this handler. Writing
  // `draft` synchronously here would invalidate `dirty` while it is still being
  // computed, which Qt reports as a binding loop. Qt.callLater moves the write
  // to after the current evaluation pass.
  onCurrentKeyChanged: if (!touched) Qt.callLater(adoptIfClean)

  Component.onCompleted: reset()

  // Escape closes the editor — it bubbles up here from whichever field has
  // focus, since QQC2 TextField doesn't consume it.
  Keys.onEscapePressed: closed()

  // The shipped-panel idiom for inline editors: focus a real control the moment
  // the editor appears (see network's password field). Landing focus on a plain
  // Item would leave typed keys dead and Tab navigation stranded.
  onVisibleChanged: if (visible) Qt.callLater(focusFirstField)

  function focusFirstField() {
    if (!visible) return
    commandField.forceActiveFocus()
  }

  function adoptIfClean() {
    if (!touched) reset()
  }

  function reset() {
    draft = Model.editorDraft(currentKey)
    touched = false
    rebuildParams()
    syncFields()
    paramsSynced()
  }

  function rebuildParams() {
    var rows = status ? Model.paramRows(status, draft.module, draft["function"], draft.params) : []
    var names = rows.map(function(row) { return { name: row.name, placeholder: row.placeholder } })
    // Identity guard: an unchanged name set must not touch the model, or the
    // Repeater rebuilds delegates for nothing.
    if (JSON.stringify(names) !== JSON.stringify(paramNames)) paramNames = names
  }

  // Push draft values into the controls. Focused fields and open popups are
  // left alone so a sync landing mid-interaction cannot fight the user.
  function syncFields() {
    if (!commandField.activeFocus) commandField.text = draft.command
    if (!labelField.activeFocus) labelField.text = draft.text
    if (!colorField.activeFocus) colorField.text = draft.textColor
    if (!moduleDropdown.popupOpen) moduleDropdown.value = draft.module
    if (!functionDropdown.popupOpen) functionDropdown.value = draft["function"]
    if (!iconDropdown.popupOpen) iconDropdown.value = draft.icon
  }

  function paramValueFor(name) {
    var value = draft.params ? draft.params[name] : undefined
    return (value === undefined || value === null) ? "" : String(value)
  }

  function setField(name, value) {
    if (String(draft[name] || "") === String(value)) return
    var next = Model.shallowCopy(draft)
    next.params = Model.shallowCopy(draft.params)
    next[name] = value
    // Switching or clearing the module invalidates the function and its params.
    if (name === "module") {
      next["function"] = ""
      next.params = {}
    }
    if (name === "function") next.params = {}
    draft = next
    touched = true
    if (name === "module" || name === "function") {
      rebuildParams()
      paramsSynced()
    }
    syncFields()
  }

  function setParam(name, value) {
    if (String(draft.params[name] || "") === String(value)) return
    var next = Model.shallowCopy(draft)
    next.params = Model.shallowCopy(draft.params)
    next.params[name] = value
    draft = next
    touched = true
  }

  function save() {
    if (!service) return
    service.saveKey(keyIndex, Model.editArguments(draft, original))
    touched = false
    saved()
  }

  function removeKey() {
    if (!service) return
    service.clearKey(keyIndex)
    touched = false
    closed()
  }

  implicitHeight: column.implicitHeight

  ColumnLayout {
    id: column
    anchors.left: parent.left
    anchors.right: parent.right
    spacing: Style.space(10)

    // ── header ───────────────────────────────────────────────────────────────
    RowLayout {
      Layout.fillWidth: true
      spacing: Style.space(8)

      Text {
        Layout.fillWidth: true
        text: (root.isNew ? "New key " : "Key ") + root.keyIndex
        color: root.foreground
        font.family: root.fontFamily
        font.pixelSize: Style.font.subtitle
      }

      PanelActionButton {
        iconText: "󰑓"
        tooltipText: "Revert changes"
        foreground: root.foreground
        fontFamily: root.fontFamily
        enabled: root.dirty
        opacity: enabled ? 1.0 : 0.35
        onClicked: root.reset()
      }

      PanelActionButton {
        iconText: "󰩹"
        tooltipText: "Delete this key"
        foreground: Color.urgent
        fontFamily: root.fontFamily
        enabled: !root.isNew
        opacity: enabled ? 1.0 : 0.35
        onClicked: root.removeKey()
      }

      PanelActionButton {
        iconText: "󰅖"
        tooltipText: "Close editor"
        foreground: root.foreground
        fontFamily: root.fontFamily
        onClicked: root.closed()
      }
    }

    // Parts of the key this editor doesn't cover are preserved on save (merge
    // semantics), but say so rather than leaving them invisible.
    Text {
      Layout.fillWidth: true
      visible: !!(root.currentKey && (root.currentKey.poll || root.currentKey.textCommand))
      text: "This key also has " +
            (root.currentKey && root.currentKey.poll ? "a poll block" : "live text") +
            " — saved edits keep it, but edit it in config.yaml"
      color: root.dim
      font.family: root.fontFamily
      font.pixelSize: Style.font.caption
      wrapMode: Text.WordWrap
    }

    // ── action: module function, or a plain shell command ────────────────────

    FieldLabel {
      text: "MODULE"
      visible: root.status && root.status.modules.length > 0
    }

    Dropdown {
      id: moduleDropdown
      Layout.fillWidth: true
      visible: root.status && root.status.modules.length > 0
      showLabel: false
      foreground: root.foreground
      accent: root.accent
      fontFamily: root.fontFamily
      options: root.status ? Model.moduleOptions(root.status) : []
      onChanged: function(v) { root.setField("module", v) }
    }

    FieldLabel { text: "FUNCTION"; visible: root.usingModule }

    Dropdown {
      id: functionDropdown
      Layout.fillWidth: true
      visible: root.usingModule
      showLabel: false
      foreground: root.foreground
      accent: root.accent
      fontFamily: root.fontFamily
      options: root.status ? Model.functionOptions(root.status, root.draft.module) : []
      onChanged: function(v) { root.setField("function", v) }
    }

    FieldLabel {
      text: "PARAMETERS"
      visible: root.usingModule && root.paramNames.length > 0
    }

    Repeater {
      model: root.usingModule ? root.paramNames : []

      RowLayout {
        id: paramRow
        required property var modelData
        Layout.fillWidth: true
        spacing: Style.space(8)

        Text {
          Layout.preferredWidth: Style.space(76)
          text: paramRow.modelData.name
          color: root.dim
          font.family: root.fontFamily
          font.pixelSize: Style.font.bodySmall
          elide: Text.ElideRight
        }

        TextField {
          id: paramField
          Layout.fillWidth: true
          foreground: root.foreground
          accent: root.accent
          placeholderText: paramRow.modelData.placeholder
          Component.onCompleted: text = root.paramValueFor(paramRow.modelData.name)
          onTextEdited: root.setParam(paramRow.modelData.name, text)
        }

        Connections {
          target: root
          function onParamsSynced() {
            if (!paramField.activeFocus) paramField.text = root.paramValueFor(paramRow.modelData.name)
          }
        }
      }
    }

    FieldLabel { text: root.usingModule ? "COMMAND — OVERRIDES THE MODULE" : "COMMAND" }

    TextField {
      id: commandField
      Layout.fillWidth: true
      foreground: root.foreground
      accent: root.accent
      placeholderText: "shell command to run on press"
      onTextEdited: root.setField("command", text)
    }

    PanelSeparator { Layout.fillWidth: true; foreground: root.foreground }

    // ── appearance ───────────────────────────────────────────────────────────

    FieldLabel { text: "ICON" }

    Dropdown {
      id: iconDropdown
      Layout.fillWidth: true
      showLabel: false
      foreground: root.foreground
      accent: root.accent
      fontFamily: root.fontFamily
      options: root.status ? Model.iconOptions(root.status) : []
      onChanged: function(v) { root.setField("icon", v) }
    }

    RowLayout {
      Layout.fillWidth: true
      spacing: Style.space(8)

      ColumnLayout {
        Layout.fillWidth: true
        spacing: Style.spacing.labelGap

        FieldLabel { text: "LABEL" }

        TextField {
          id: labelField
          Layout.fillWidth: true
          foreground: root.foreground
          accent: root.accent
          placeholderText: "text drawn on the key"
          onTextEdited: root.setField("text", text)
        }
      }

      ColumnLayout {
        Layout.preferredWidth: Style.space(104)
        spacing: Style.spacing.labelGap

        FieldLabel { text: "COLOUR" }

        TextField {
          id: colorField
          Layout.fillWidth: true
          foreground: root.foreground
          accent: root.accent
          placeholderText: "white"
          onTextEdited: root.setField("textColor", text)
        }
      }
    }

    // ── footer ───────────────────────────────────────────────────────────────

    RowLayout {
      Layout.fillWidth: true
      spacing: Style.space(8)

      Text {
        Layout.fillWidth: true
        text: root.dirty ? "Unsaved changes" : "Saved edits reload the deck immediately"
        color: root.dirty ? root.foreground : root.dim
        font.family: root.fontFamily
        font.pixelSize: Style.font.caption
        elide: Text.ElideRight
      }

      Button {
        text: "Save"
        foreground: root.foreground
        accent: root.accent
        fontFamily: root.fontFamily
        enabled: root.dirty
        opacity: enabled ? 1.0 : 0.4
        onClicked: root.save()
      }
    }
  }

  // FieldLabel is the small-caps heading above each control.
  component FieldLabel: PanelSectionHeader {
    Layout.fillWidth: true
    foreground: root.foreground
    fontFamily: root.fontFamily
  }
}